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1
Hakestam, Ulf. "On the prosthodontic patient an investigation of factors influencing patient expectations and satisfaction with extensive prosthodontic care /." Malmö, Sweden : Dept. of Prosthetic Dentistry, Center for Oral Health Sciences, Lund University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/39608499.html.
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Cagidiaco, Edoardo Ferrari. "Periodontal evaluation of restorative and prosthodontic margins." Doctoral thesis, Università di Siena, 2021. http://hdl.handle.net/11365/1126080.
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Prosthodontic and periodontal correlation on teeth
In the daily dental practice 3 fundamental/empiric/clinical parameters have a role to establish the clinical success of prosthodontic treatment: function, aesthetic and longevity of the restorations. But, from a scientific point of view, how do we rate the success of the restorations?
When analyzing the existing literature, it can be noted that many authors focus their attention on the precision of the margin, to pursuit a small gap between the abutment and the crown, and to achieve the clinical success.
Christensen et al.1 and Mc Lean & Von Fraunhofer2 investigated the margins’ clinical acceptability by dentists and asked to measure the gap between the abutment and the crown to a number of practitioners: it was shown that a clinician can clinically appreciate a gap not lower than 120 microns using a sharp explorer. This result may end in a not sure and sufficient seal between the crown and abutment, and consequently leakage at the margins.
This finding is not in agreement with the existing data coming from an in vitro study in which the acceptable marginal gap is lower than 50 microns3 Sorensen3 reported that small defects less or equal then 0,050 mm were associated with significantly less fluid flow and bone loss than defects exceeding this value.
Martignoni4-5 reported that there are variable definitions regarding what constitutes a margin that cab ne clinically acceptable, and there is no definite threshold for the maximum marginal discrepancy that is clinically acceptable. Many authors accept the criteria established by McLean and Von Fraunhofer2, they completed a 5-year examination of 1000 restorations and concluded that 120 microns should be considered the maximum marginal gap.
The adaptation, the precision and the quality of the restoration margin can be of greater significance in terms of gingival health, than the position of the margin6.
According to Lang et al. 7 following the placement of restorations with overhanging margins, a subgingival flora was detected which closely resembled that of chronic periodontitis. Following the placement of the restorations with clinically perfect margins, a microflora characteristic for gingival health or initial gingivitis was observed.
In patients with suitable oral hygiene, tooth-supported and implant-supported crowns with intra-sulcular margins were not predisposed to unfavorable gingival and microbial responses8.
Even among patients receiving regular preventive dental care, subgingival margins are associated with unfavorable periodontal reactions9.
Ercoli and Caton10, in a systematic review, describe how placement of restoration margins within the junctional epithelium and supracrestal connective tissue attachment can be associated with gingival inflammation and, potentially, recession or periodontal pocket. The presence of fixed prostheses finish line within the gingival sulcus or wearing of partial, removable dental prostheses does not cause gingivitis if the patients are complaint with self-performed plaque control and periodic maintenance. Procedures adopted for the fabrication of dental restorations and fixed prostheses have the potential to cause traumatic loss of the periodontal supporting tissue. They concluded that restoration margins located within the gingival sulcus do not cause gingivitis if the patients are complaint with self-performed plaque control and periodic maintenance.
Tooth-supported and/or tooth-retained restorations and their design, fabrication, delivery, and materials, have often been associated with plaque retention and loss of attachment. Restoration margins placed within the junctional epithelium and supracrestal connective tissue attachment can be associated with inflammation and, potentially, recession. Factors related to the presence, design, fabrication, delivery and materials of tooth-supported prostheses seem to influence the periodontium, generally related to localized increase in plaque accumulation and, less often, to traumatic and allergic reactions to dental materials10.
Jansson showd that the influence of a marginal overhang on pocket depth and radiographic attachment decrease with increasing loss of periodontal attachment in periodontitis-prone patients, and the effect on pocket depth of a marginal overhang may act synergistically, potentiating the effect of poor oral hygiene11.
Subgingival restorations with their apical borders still located subgingivally after periodontal treatment should be regarded as a risk factor in the progression of periodontitis12. Consequently, placement of the restoration margin supragingivally is recommended, especially in periodontitis-prone patients with an insufficient plaque control12.
Dental restorations may be suggested as a risk indicator for periodontal disease and tooth loss. Routine SPT (Supportive Periodontal Therapy) was found to be associated with decrease in the prevalence of deep PPD over time, and it is of the utmost importance in maintaining periodontal health, especially adjacent to teeth with restorations. Finally, these findings may support the treatment of caries lesions and faulty restorations as part of a comprehensive cause-related therapy and should be followed by a regular maintenance program13.
The relationship between dental restorations and periodontal status has been examined for some time. Research has shown that overhanging dental restorations and subgingival margin placement play an important role providing an ecologic niche for periodontal pathogens14.
An overhanging dental restoration is primarily found in the class II restoration, since access for interdental finishing and polishing of the restoration, and cleansing is often difficult in these areas, even for patients with good oral hygiene. Many studies have shown that there is more periodontal attachment loss and inflammation associated with teeth with overhangs than those without. Presences of overhangs may cause an increase in plaque formation15-21 and a shift in the microbial composition from healthy flora to one characteristic of periodontal disease14.
The location of the gingival margin of a restoration is directly related to the health status of the adjacent periodontium8. Numerous studies8-12-25
have shown that subgingival margins are associated with more plaque, more severe gingival inflammation and deeper periodontal pockets than supragingival ones. In a 26-year prospective cohort study, Schatzle et al. 25 followed middle class Scandinavian men for a period of 26 years. Gingival index, and attachment level were compared between those who did and those who did not have restorative margins greater than 1mm from the gingival margin. After 10 years, the cumulative mean loss of attachment was 0.5 mm more for the group with subgingival margins. This was statistically significant. At each examination during 26 years of the study, the degree of inflammation in the gingival tissue adjacent to subgingival restorations was much greater than in the gingiva adjacent to supragingival margins. This is the first study to document a time sequence between the placement of subgingival margins and periodontal attachment loss, confirming that the subgingival placement of margins is detrimental to gingival and periodontal health.
Plaque at apical margin of a subgingival restoration will cause periodontal inflammation that may in turn destroy connective tissue and bone approximately, 1-2 mm away from inflamed area14.
Determination of the distance between the restorative margin and the alveolar crest is often done with bitewing radiographs; however, it is important to remember that a radiograph is a 2-dimensional representation of 3-dimensional anatomy and structure. Thus, clinical assessment and judgment are important adjuncts in determining if, and how much, bone should be removed to maintain adequate room for the dento-gingival supra crestal connective tissue height attachment14.
Although surface textures of restorative materials differ in their capacity to retain plaque26, all of them can be adequately maintained if they are correctly polished and accessible to patient care27. This includes underside of pontics. Composite resins are difficult to finish interproximally and may be more likely to show marginal defects than other materials28. As a result, they are more likely to harbor bacterial plaque29. Intra-subject comparisons of unilateral direct compositive “veneers” showed a statistically significant increase in plaque and gingival indices adjacent to the composites, 5-6 years after placement28. In addition, when a diastema is closed with composite, the restorations are often overcontoured in the cervical-interproximal area, leading to increased plaque retention28. As more plaque is retained, this could pose a significant problem for a patient with moderate to poor oral hygiene14.
For that, in absence of more specific prosthodontic parameters to evaluate the integration of crowns in to the periodontal environment, another way to determine the success and health of the restoration is to use the periodontal parameters such as: PPD (Periodontal Probing Depth) that is the measurement of the periodontal sulcus/pocket between the gingival margin and the bottom of the sulcus/pocket; REC (Recession) is the apical migration of the gingival margin measured with the distance between the gingival margin and the CEJ (Cement-Enamel Junction); PI (Plaque Index) the index records the presence of supragingival plaque; BOP (Bleeding On Probing) the presence or not of bleeding on surfaces of the teeth during the probing.
The aim of this study/thesis was to propose a clinical procedure to evaluate single unit restorations and their relations with periodontal tissues by a new clinical score: the FIT ( Functional Index for Teeth). FIT, that is a novel index for the assessment of the prosthetic results of lithium disilicate crowns, based on seven restorative-periodontal parameters, that evaluate crowns placed on natural abutments, and want to be a reliable and objective instrument in assessing single partial crown success and periodontal outcome as perceived by patients and dentists.
3
Allport, David M. "Evaluation of two reference planes to the horizon in the natural head position." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2565.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains vii, 35 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 29-30).
4
Salih, Mayson. "Disinfection Procedures: Effects on the dimensional accuracy of Gypsum casts." Thesis, University of the Western Cape, 2007. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_3067_1257931628.
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The aim of the study was to assess the dimensional accuracy of Gypsum models following chemical disinfection of the impressions and to compare it with the accuracy of gypsum models exposed to microwave irradiation disinfection. Results indicated that the dimensional accuracy of the gypsum models disinfected in a microwave oven did not differ significantly from models in the control group. Except for models produced from SS white (SS White group, England) impressions where models irradiated in microwave exhibit significant improvement in the dimensional accuracy when compared with control group...
5
Zeiaei-Nafchi, Saeid. "Dimensional changes of poysulfide [sic] impression materials over time." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1300.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains vii, 47 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 41-46).
6
Chan, Hung-chiu Kingsley. "Cast keepers for dental magnets : effects of laboratory procedures /." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31490335.
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7
Razek, Ammar A. Abdul. "Clinical Significance Of Severe Tooth Undercuts In Prosthodontics - A Quantitative Analysis." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/4951.
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Alsadon, Omar. "Evaluating PolyEtherKetoneKetone (PEKK) polymer used for fabricating fixed prosthodontics." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/17181/.
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Dental alloys, and later zirconia, have been used in dentistry as frameworks for many years in making crowns and bridges veneered with ceramic e.g. feldspathic porcelain. Such methods of restoring teeth have been extensively studied both in the laboratory and clinically. Although such substructures have excellent strength there remains a large properties mismatch between these materials and bone or dentine e.g. elasticity. Furthermore, other drawbacks have been documented such as possible allergies, colouring of alloy margins, veneer chipping and excessive wear to opposing natural dentition. Polyaryletherketone (PAEK) thermoplastic biomaterial polymers such as polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) have been successfully applied in different medical applications with the latter recently being introduced to dentistry as a restorative material. The material is called Pekkton® ivory (Cendres+Métaux, SA, Switzerland) and is proposed to be used for fabricating both monolithic and bi-layered structures veneered with indirect composite resin. The manufacturer recommends methods similar to well-established restorations such as alloy and ceramic based crowns which makes it a user friendly material for both dental clinics and laboratories. Furthermore, the material’s properties such as high strength, low elastic modulus close to that of dentine, high temperature, chemical, hydrolysis and wear resistance, makes it a promising material for the replacement of tooth material. There is little published data about this material and hence the aim of this research was to evaluate the manufacturing process, aesthetic properties, structural integrity and durability of bi-layered crowns made from PEKK based thermoplastic high performance polymer (Pekkton® ivory, Cendres+Métaux, SA) and veneered with indirect light cured composite (Vita VM LC, VITA Zahnfabrik H. Rauter GmbH & Co.KG, DE). The processing route for Pekkton® ivory is either via milling or hot-pressing and the procedures were compared. The polymer-based restoration was compared to equivalent zirconia and metal based bi-layered restoration systems veneered with either light cured composite resin or feldspathic porcelain. Optical properties of each crown system were compared using a UV and visible light spectrophotometer. Structural integrity was compared for each system by testing the fracture resistance of the crowns using a universal testing machine and durability was evaluated by testing the fatigue limit and fatigue life using a fatigue chewing apparatus. The research hypothesis is that the PEKK polymer as anunderlying substructure material will perform equivalently to metal and zirconia substructures when veneered with light cured composite in the aspects of optical properties, strength and durability. The outcome of the study established a pressing protocol for PEKK using a standard ceramic pressing furnace where the pressed samples showed no significant differences in the CIEL*a*b* colour values, hardness or biaxial flexural strength to those samples produced via milling. There was no significant optical difference between the systems compared, the study found no evidence of difference in the CIEL*a*b* colour value of PEKK, zirconia or metal based samples when veneered with the same composite veneer. However, zirconia based groups displayed greater translucency with the composite veneer and feldspathic porcelain veneer. The fracture resistance of the PEKK and metal composite veneered crowns showed to be comparable, whereas zirconia based crowns demonstrated significantly lower fracture resistance. The durability of the PEKK composite veneered crowns showed the highest fatigue limit in comparison to the zirconia and metal composite veneered crowns. Similarly they showed the highest survival rate in the fatigue life assessment under the same cyclic load. Furthermore, the fracture mode was significantly different than observed with the zirconia and metal based crowns. The conclusion was that this material is promising for use as a restorative material and that clinical evaluation should be undertaken.
9
Collin, Bagewitz Ingrid. "Prosthodontics, care utilization and oral health-related quality of life /." Malmö : Malmö högskola, 2007. http://dspace.mah.se/handle/2043/3896.
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Bagewitz, Ingrid Collin. "Prosthodontics, care utilization and oral health-related quality of life." Malmö [Sweden] : Malmö högskola, Dept. of Prosthetic Dentistry, Dept. of Oral Public Health, Faculty of Odontology, 2007. http://catalog.hathitrust.org/api/volumes/oclc/122895139.html.
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Begg, Tasneem. "Photoelastic stress patterns produced by the angled distal implants in the All-on-Four concept." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_3791_1254295343.
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The purpose of this study was to investigate the stress produced around the angled distal implants under simulated occlusal loading in the All-on-Fourª
concept by means of two-dimensional photoelastic stress models.
12
Smith, Christopher David. "Prosthodontic maintenance of implant-supported prostheses." Master's thesis, Faculty of Dentistry, 2001. http://hdl.handle.net/2123/4667.
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This work was digitised and made available on open access by the University of Sydney, Faculty of Dentistry and Sydney eScholarship . It may only be used for the purposes of research and study. Where possible, the Faculty will try to notify the author of this work. If you have any inquiries or issues regarding this work being made available please contact the Sydney eScholarship Repository Coordinator - ses@library.usyd.edu.au
13
陳鴻釗 and Hung-chiu Kingsley Chan. "Cast keepers for dental magnets: effects of laboratory procedures." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B45007706.
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Abu-Hammad, Osama Abdalla M. "The influence of some factors on compressive stress levels around dental implants." Thesis, University of Bristol, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337637.
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Bacchi, Ataís 1986. "Resin cements modified with thiourethane polymer additives = cement layer and bonding interface properties." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288589.
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Orientador: Rafael Leonardo Xediek ConsaniTexto em português e inglês
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-25T06:50:42Z (GMT). No. of bitstreams: 1 Bacchi_Atais_D.pdf: 1480731 bytes, checksum: de48bd5276e26a7e24f1506dd970897a (MD5) Previous issue date: 2014
Resumo: O objetivo neste estudo foi formular cimentos resinosos a partir de oligômeros tiouretanos, com o propósito de melhorar as propriedades mecânicas do material e minimizar a contração e a tensão de polimerização. Materiais fotopolimerizados e de ativação dupla foram avaliados. Dois oligômeros foram sintetizados ao combinar 1,6-hexanodiol-diisocianato (HDDI) (alifático) com pentaeritritol tetra-3-mercaptopropionato (PETMP) ou 1,3-bis(isocianato-1-metiletil) benzeno (BDI) (aromático) com trimetilol-tris-3-mercaptoproprianato (TMP), na proporção de 1:2 de isocianato e tiol, mantendo grupos tiol pendentes. Inicialmente, 10-30% em peso de ambos os tiouretanos foram adicionados à matriz orgânica formada por BisGMA-UDMA-TEGDMA (nas proporções 50-30-20%, em peso) para o cimento experimental fotopolimerizado. A este, 25% em peso de partículas inorgânicas foram adicionadas. Para o cimento de cura dual, composto pela mesma matriz orgânica e partículas de carga, e para dois materiais comerciais ¿ RelyX Veneer e RelyX Ultimate (3M Espe) - apenas a versão aromática em 10 e 20% em peso foi avaliada. Para todos os materiais, as propriedades mecânicas foram avaliadas através do teste de flexão por três pontos (ISO 4049) para a resistência à flexão (RF), módulo de elasticidade (E) e tenacidade (T). A tenacidade à fratura (KIc) foi avaliada em amostras entalhadas (ASTM Standard E399-90). A tensão de polimerização (TP) foi avaliada usando o aparelho Bioman. Os materiais fotopolimerizados foram avaliados quanto à contração de polimerização (CP) pelo método do disco aderido e a cinética de polimerização (grau de conversão (GC), taxa máxima de polimerização (Rpmax) e vitrificação) avaliadas por infravermelho. A união de uma cerâmica vítrea e um compósito restaurador indireto à dentina foi avaliada com o cimento comercial dual com 0, 10 e 20 % de tiouretano. Os resultados foram submetidos à Análise de Variância e teste de Tukey (?=5%). Quanto ao GC, ocorreu aumento pela utilização da versão alifática nos cimentos experimentais fotoativados; entretanto, a versão aromática não promoveu alteração relevante no GC final dos materiais. Rpmax foi menor nos grupos tiouretanos sendo também significantemente menor para os alifáticos quando comparados aos aromáticos. Apesar de os tiouretanos influenciarem a vitrificação (p=0,035) no cimento experimental, os resultados não foram conclusivos pela análise de Tukey. No cimento comercial foi observado aumento da vitrificação pelo uso do oligômero. Nos cimentos experimentais, RF aumentou com o oligômero aromático e 20% em peso do alifático nos cimentos fotopolimerizados; para E, a versão aromática no cimento com ativação dupla e 10% em peso no material fotopolimerizado causou aumento nos valores. Os materiais comerciais tiveram redução de E com 20% em peso de oligômero, decorrente da redução da proporção de carga inorgânica da matriz. Aumento significante em tenacidade ocorreu nos grupos alifáticos no material fotopolimerizado e para 20% em peso de aromático no cimento dual. K1c aumentou significativamente em ambos os materiais experimentais contendo tiouretano em ambas as concentrações, sendo mais pronunciada em alifáticos na versão fotopolimerizada. Ainda, KIc aumentou com 20% em peso do oligômero em materiais comerciais. A CP reduziu significantemente nos grupos tiouretanos, especialmente para o oligômero alifático no cimento experimental fotopolimerizado. A TP reduziu com os oligômeros de maneira mais acentuada para alifáticos no cimento experimental fotopolimerizado. O uso dos aromáticos em cimentos de ativação dupla também causou redução na TP, e quando com 20% em peso nos materiais comerciais. A modificação do cimento comercial de ativação dupla com 20% em peso do oligômero aromático aumentou a adesão do compósito indireto e da cerâmica vítrea à dentina coronária. Em geral, oligômeros tiouretanos melhoraram as propriedades dos cimentos resinosos avaliados
Abstract: The aim of this study was to formulate resin cements with thio-urethane oligomers to improve mechanical properties and minimize shortcomings related to the volumetric shrinkage and polymerization stress. Light- and dual-cured materials were evaluated. Oligomers were synthesized by combining 1,6-Hexanediol-diissocyante (aliphatic) with pentaerythritol tetra-3-mercaptopropionate (PETMP) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (aromatic) with trimethylol-tris-3-mercaptopropionate (TMP), at 1:2 isocyanate:thiol, leaving pendant thiols. Oligomers were added at 10-30wt% to BisGMA-UDMA-TEGDMA (5:3:2). 25wt% silanated inorganic fillers were added. The dual-cured cement, composed by the same organic matrix and filler particles, and for two commercial cements (RelyX Veneer e RelyX Ultimate; 3M Espe) were only evaluated with the addition of the aromatic version in 10 and 20 wt%. For all materials, the mechanical properties were evaluated by the three-point bending test (ISO 4049) for the flexural strength (FS) elastic modulus (E) and toughness (T). The fracture toughness was evaluated with notched specimens (ASTM Standard E399-90). The polymerization stress (PS) was evaluated in the Bioman. For the light-cured materials, the volumetric shrinkage (VS) was evaluated by the bonded-disc method and the polymerization kinetics ¿ degree of conversion (DC), maximum rate of polymerization (Rpmax) and vitrification ¿ evaluated by near-infrared (NIR). The bonding of a glass ceramic and an indirect composite to dentin were evaluated with the dual-cured commercial cement with 0, 10 and 20 wt% of thio-urethane. Data were analyzed with ANOVA and Tukey¿s test (?=5%). Regarding the DC, an increase was observed in the light-cured materials containing the aliphatic version. The aromatic oligomer did not promote relevant influence the materials. Rpmax was lower for thio-urethane groups being also significantly lower for the aliphatic group when compared to the aromatic. ANOVA has shown the thio-urethane influencing the vitrification (p=0.035) in the experimental cement, but the results were not conclusive by the Tukey¿s test. For the commercial cement, an increase in the vitrification was observed in the thio-urethane-modified group. For experimental cements, FS increased with the use of 10-30 wt% aromatic oligomer and with 20 wt% of aliphatic for light-cured cements. E was only higher for the aromatic version at 10 wt%. The commercial cements presented a reduction in E with 20 wt% of oligomer caused by the reduction in the filler proportion. A significant increase in T occurred in the aliphatic groups for the light-cured group and for 20 wt% of aromatic in the dual-cured cement. KIc significantly increased in both experimental materials formulated with thio-urethane for both concentrations, being more evident for the aliphatic group in the light-cured version. KIc also increased with the aromatic oligomer in commercial materials. The VS was significantly reduced in the thio-urethane groups, mainly for the aliphatic version in the light-cured cement. The PS decreased in the groups formulated with oligomers in the light-cured experimental materials, being also significant for aliphatics. The use of aromatic oligomer also reduced the PS when added to a 20 wt% proportion of organic matrix. The modification of a dual-cured commercial cement with 20wt% of aromatic oligomer led to an increase in the bond strength of an indirect composite and a glass ceramic to the coronal dentin. Thus, it can be concluded that thio-urethane oligomers improved the properties of resin cements
Doutorado
Protese Dental
Doutor em Clínica Odontológica
16
Näpänkangas, R. (Ritva). "Fixed metal ceramic prostheses:treatment need, complications and survival of conventional fixed prosthodontics." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514265408.
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Abstract
The aims of this study were to evaluate the treatment need of fixed
bridges according to the distribution of pontics in dentition in different
age groups, and to investigate the primary and late complications and
survival of the conventional fixed metal ceramic prostheses, as well as
patients' satisfaction with the prosthetic treatment.
The whole material consisted of the patients treated with fixed metal
ceramic prostheses by undergraduate students at the Institute of Dentistry
during the years 1984 - 1996. There were altogether 772 patients, 460
women (60 %) and 312 men (40 %). Their mean age was 47 years (23 - 81
years). Altogether 944 single metal ceramic crowns and 543 fixed bridges
(1374 abutments and 807 pontics) were prepared.
It can be concluded that the fixed bridges are most often prepared to
replace upper first premolars and lower first molars also in the future.
The most usual primary complications related to fixed bridges occurred
during preprosthetic endodontic treatment of abutment teeth and during the
preparation of the root canals. Previous restoration of the prepared tooth
does not have any marked effect on the prognosis of single crowns with
dowels, although anatomically complicated upper lateral incisors and upper
first premolars need special attention in the treatment planning. Patients
were satisfied with aesthetics and function of the fixed metal ceramic
prostheses. Late complications found in clinical examinations were few,
and the survival rate for the fixed metal ceramic bridge prostheses was
calculated to be 84 % after 10 years, long fixed bridges having a lower
survival than the shorter ones.
The treatment need for conventional fixed bridges seems to be highest
among patients over 50 years of age in the future. Age does not influence
the longevity of the fixed prostheses, but basic circumstances of the
mouth, especially low secretion of saliva affected by diseases and/or
medications and high scores of lactobacilli and streptococcus mutans of
the saliva seem to decrease the survival.
17
Alyassin, Waleed. "The influence of heat production relative to drill wear during osteotomy preparation by different implant drill systems a comparison study between ceramic and conventional implant drill systems /." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/11068.
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Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains vi, 41 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 37-41).
18
Almansour, Haitham. "The development of titanium/zirconia composites using powder metallurgy technology for fixed prosthodontics." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/8437/.
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Khan, Saadika B. "Mechanical and handling properties of light-cured acrylic resin custom tray material." Thesis, University of the Western Cape, 2007. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_4268_1227009157.
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Both light-cured (LC) and chemically-cured (CC) acrylic resin custom tray materials are used at the Oral Health Centre, Faculty of Dentistry, University of the Western Cape. At present, the CC acrylic is the standard for formal undergraduate teaching and training. The LC material is not part of routine didactic teaching as little evidence-based scientific information is available with regards to its properties and its usage in the clinical environment. Negative effects have caused researchers to focus on alternatives and to research for other materials with more advantageous properties. The objectives of this study was to determine the linear dimensional shrinkage and fracture toughness of light-cured acrylic custom tray materials and compare it to the chemically-cured type. Also to evaluate the acceptance of light-cured acrylic resin custom trays by undergraduate students.
20
Overturf, Jan Hendrik. "The effects of diferent reinforcements on the fracture toughness of provisional restorative materials." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2033_1254998751.
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One of the most critical aspects of successful crown and bridgework is temporary restorations. Failure of temporary restoratins often affects the patient's confidence and mau result in unscheduled appointments for repair. This study compared the the fracture toughness of two materials commonly used to fabricate provisional restorations, namely Coldpac, a polymethyl methacrylate and Protemp 3 Garant, a bis-acryl composite. It also compard the fracture toughness of the two materials when reinforced with stainless steel wire, glass fibers and polythylene fibers.
21
Mackie, Andrew, and n/a. "Mandibular two-implant overdentures : prosthodontic maintenance using different matrices with different loading strategies." University of Otago. School of Dentistry, 2007. http://adt.otago.ac.nz./public/adt-NZDU20071221.142609.
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Objective: To determine the long-term prosthodontic maintenance requirements of mandibular unsplinted, two-implant overdentures, using different attachment systems and loading protocols.
Materials and Methods: An original total of 106 participants were randomly allocated to one of four different implant systems (Brånemark, Steri-Oss, Straumann and Southern Implant systems). Three different loading strategies were used (2-weeks, 6-weeks and 12-weeks). A total of six different unsplinted attachment systems for mandibular two-implant overdentures were used with the four implant systems. These attachment systems included; the Brånemark gold matrix, Straumann gold matrix, Straumann titanium matrix, Southern Implants plastic matrix, Southern Implants palladium matrix and the Steri-Oss rubber matrix. Each matrix group was allocated to one or more loading strategies and data related to prosthodontic maintenance events was collected prospectively from overdenture insertion (baseline) to year eight, according to predefined categories. Data were analysed using SPSS, and levels of statistical significance were set at P < 0.05. To test for significance between multiple groups, ANOVA was used. Where a statistically significant difference existed, a one way ANOVA with Post Hoc tests was performed.
Results: A total of 90 participants from all matrix groups were followed for six-years and loading comparisons could only be made up to this time. The Southern palladium matrix was followed for only six-years therefore it could not be included in the eight year analysis. A total of 69 participants remained in the randomised controlled trial after eight years. Mandibular two-implant overdentures fitted with the Steri-Oss rubber matrix displayed the highest mean number of maintenance events at 32.2 (SD 14.5) followed by the Brånemark matrix group at 28.8 (SD 12.6), the Straumann titanium matrix group at 24.9 (SD 10.7) and the Straumann gold matrix group at 12.8 (SD 8.2), over an eight year period. The Southern plastic matrix group had the lowest average number of maintenance events (8.7 SD 4.2) over the eight-year period and this was significant compared with all other groups (P < 0.05). Over six years, there were no significant differences found between the number of prosthodontic maintenance events and the loading strategy used. On average, the Straumann gold matrix lasted for 3.9 (SD 2.1) years which was significantly longer than all other matrices (P < 0.05) over six years. The Southern palladium (3.1 SD 1.7), Brånemark gold (2.7 SD 1.5) and Southern plastic (2.5 SD 1.4) matrices all lasted significantly longer than the Straumann titanium (1.7 SD 0.8) and the Steri-Oss rubber (1.4 SD 0.7) matrices over six years.
Conclusions: Mandibular two-implant overdentures using the Southern Implants plastic cap required significantly less prosthodontic maintenance events compared with all other matrix groups. The Straumann gold matrix required significantly less prosthodontic maintenance compared with the Steri-Oss rubber matrix (P<0.05). The Straumann gold matrix also demonstrated the greatest longevity compared with all other matrices (P<0.05). There was no significant difference in the number of prosthodontic maintenance events of two-implant overdentures when loaded at 2, 6 or 12-weeks after implant placement. The prosthodontic maintenance requirements of unsplinted mandibular two-implant overdentures are dependant upon the attachment system chosen.
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Shaw, Andrew John. "The durability of indirect composite veneers : a clinical and laboratory study." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366546.
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Du, Toit Adriaan Claassen. "An oral pathological profile for the preprosthetic evaluation of edentulous patients in the Western Cape of South Africa and the implications for training." Thesis, Peninsula Technikon, 2003. http://hdl.handle.net/20.500.11838/1531.
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Thesis( Masters degree(Dental Technology))--Peninsula Technikon, Cape Town, 2003This study explored the oral pathological conditions and related normal aberrations found within an edentulous sample group of the Western Cape of South Africa. The initial literature review concentrated on similar epidemiological surveys from a national and international perspective, from which a research framework was formulated and then applied to the chosen sample size. Statistical analysis revealed the mean age of the sample group as 57,3 +1- 1 years and that the male, female ratio was 1:2.16. Results indicated that the percentage of healthy individuals were 78%. Normal aberrations such as mobile alveolar ridge (flabby ridge) (2,6%), oral mucosal pigmentation (1,9%), chronic cheek chewing (1 %), torus mandibularis and palatinus (0,5%) had the highest incidence. Twenty three percent exhibited some sort of oral pathological condition such as denture stomatitis (7%), ulcerations (5,2%), angular cheilitis (1,8%), white lesions (4,4%), and denture-related hyperplasia (1,9%) were the most prevalent. Systemic diseases were recorded in 38,2% of patients: hypertension (22,7%), heart disorders (6,6%), diabetes mellitus (6,5%) and asthma (4,4%) were the most common. Individuals that exhibited oral pathoses were found to be wearing older dentures than individuals who replace their dentures more regularly. No significant difference was found between the age of the denture and the age of the patient. The empirical investigation revealed that the number of prominent oral conditions was low for the Western Cape of South Africa and could perhaps be incorporated into an educational module for dental technologists. A better understanding of such oral pathological conditions may aid communication and patient service between the parties involved. The concept of a more collaborative approach between the dentist and the dental technologists was discussed. Reference is made to a community service model that focuses more specifically on the needs of the poorer edentulous individuals of the Western Cape.
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O'Sullivan, Dominic. "The effect of implant geometry upon the primary stability of dental implants." Thesis, University of Bristol, 2001. http://hdl.handle.net/1983/339010c1-63ee-4eb9-b03c-b3a2b9b89dbf.
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Fathalah, Ahmed A. A. "Microstructural Observations of Laser-Sintered Specimens for Prosthodontic Applications." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366286613.
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Coco, Suzanne Kemp. "A mechanical and histological study of functionally graded hydroxyapatite implant coatings." View the abstract Download the full-text PDF version, 2008. http://etd.utmem.edu/ABSTRACTS/2008-009-Coco-index.html.
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Thesis (M.S.)--University of Tennessee Health Science Center, 2008.Title from title page screen (viewed on June 10, 2008). Research advisor: Joo Leng Ong, Ph.D. Document formatted into pages (vi, 34 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 31-34).
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Ettinger, Ronald L. "Overdentures : a longitudinal perspective." Thesis, The University of Sydney, 1992. http://hdl.handle.net/2123/4645.
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Kelly, Philip G. "Long-term survival and cost-effectiveness of fixed prostheses in continuously attending patients at three private dental practices /." Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09DM/09dmk29.pdf.
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Hart, Jonathan Michael. "The influence of biofilm on the antifungal activity of amine oxide." View the abstract Download the full-text PDF version, 2009. http://etd.utmem.edu/ABSTRACTS/2009-015-Hart-index.htm.
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Thesis (M.S.)--University of Tennessee Health Science Center, 2009.Title from title page screen (viewed on August 11, 2009). Research advisor: Jegdish P. Babu, Ph.D. Document formatted into pages (ix, 32 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 28-31).
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Carneiro, Lorna Celia. "Surface characteristics and in vitro bio-acceptability of machined and cast pure titanium and titanium alloy." Thesis, Access to E-Thesis, 2003. http://upetd.up.ac.za/thesis/available/etd-09302005-135346/.
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Peçanha, Marcelo Massaroni. "Influência de diferentes tratamentos de superfícies e agentes de cimentação no processo de adesão de um sistema cerâmico à base de zircônia." Universidade de Taubaté, 2013. http://www.bdtd.unitau.br/tedesimplificado/tde_busca/arquivo.php?codArquivo=601.
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Objetivo: Avaliar a influência de diferentes tratamentos de superfície da zircônia na rugosidade superficial e na resistência de união utilizando diferentes agentes de cimentação, pré e pós-ciclagem térmica, bem como analisar a superfície de fratura. Metodologia: Foram elaborados três artigos científicos. No Capítulo 1, apresentou-se um estudo de revisão da literatura a respeito dos métodos de tratamento de superfície e os diferentes tipos de cimentos indicados para proporcionar união adesiva entre a zircônia e materiais resinosos. No Capítulo idade da superfície modificada e a resistência da união entre cerâmica e material resinoso. Os tratamentos de superfície analisados foram: jateamento com partículas de Al2O3 de 50μm, aplicação de primer contendo MDP, silicatização e silicatização associado a aplicação de primer contendo MDP, além da associação de dois tipos de cimentos resinosos, cimento resinoso modificado com monômeros fosfatados e cimento resinoso autoadesivo. Foi utilizado o teste de rugosidade e de microcisalhamento para verificar a alteração de superfície e a força de adesão proporcionada pelos grupos experimentais seguidas de análise do modo de falha para verificar as características da interface adesiva. No capítulo 3 foi realizado o mesmo delineamento do Capítulo 2, entretanto, foi associado o processo de ciclagem térmica para verificação do comportamento dos diferentes tratamentos de superfícies e materiais cimentantes, com intuito de simular parcialmente condições clínicas. Conclusões: Ambos os cimentos utilizados podem ser indicados para a cimentação adesiva da cerâmica a base de zircônia. Em relação aos cimentos resinosos modificados o tratamentos de superfície apresenta-se indispensável para possibilitar melhora na resistência de união. O tratamento com a cobertura de sílica associado ou não ao primer apresentou-se com melhores resultados. Em relação aos cimentos autoadesivos o tratamento de superfície não teve grande influência na resistência de união, porém melhores resultados foram obtidos nas superfícies tratadas com a cobertura de sílica. Após a ciclagem térmica foi observado que o cimento autoadesivo apresentou melhores valores de força de adesão em comparação ao cimento resinoso modificado, independente do tratamento de superfície realizado.Objective: To evaluate the influence of different surface treatments of zirconia in surface roughness and bond strength using different cementing agents, before and after thermal cycling as well as analyze the fracture surface. Methods: We developed three papers. In Chapter 1, presented a study of the review of the literature on the methods of surface treatment and different types of cements indicated for providing bonding between zirconia and resin materials. In Chapter 2, an experiment was designed to evaluate the influence of different types of surface treatment of ceramic and cement types on the surface roughness of the modified surface and the bond strength between compositive material and ceramics. The w yz w h A O3 50μ applying primer containing MDP, and silicatization associated with applying primer containing MDP. A resin cement modified with phosphate monomers and self-adhesive resin cement were also analyzed. Roughness and microshear test was used to verify the change of surface, and the adhesion strength provided by the experimental groups followed by analysis of the way to check the characteristics of the adhesive interface. The analyzed results were submitted to statistical analysis. In chapter 3 was used the same design done in Chapter 2, however, thermal cycling process was associated to verify the behavior of different surface treatments and materials with the aim of partially simulate clinical conditions. Conclusions: Both cements used might be indicated for the adhesive cementation of zirconia-based ceramics. Regarding resin cements modified the surface treatment has become indispensable to enable improvement in bond strength. Treatment with silica coverage with or without the primer presented with better results. Regarding the self-adhesive cement, surface treatment had no major influence on the bond strength but better results were obtained on surfaces treated with the coverage of silica. After thermocycling was observed that the self-adhesive cement had values better adhesion strength in comparison to the modified resin cement.
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Selecman, Audrey Marie. "Evaluation of osseointegration between two different modalities of hydroxyapatite implant surface coatings plasma sprayed HA coated implants and electrophoresis deposited nano HA coated implants /." View the abstract Download the full-text PDF version, 2007. http://etd.utmem.edu/ABSTRACTS/2007-008-Selecman-index.html.
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Thesis (M.S. )--University of Tennessee Health Science Center, 2007.Title from title page screen (June 30, 2008). Research advisor: Joo L. Ong, Ph.D. Document formatted into pages (vi, 47 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 41-46).
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Tieng, Chhnoeum Nitipun Jeeraphaet. "Effect of denture cleanser on the surface roughness and hardness of denture base materials /." Abstract Full Text (Mahidol member only), 2008. http://10.24.101.3/e-thesis/2551/cd424/4937437.pdf.
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Fecchio, Roberto Silveira. "Avaliação clínica de próteses dentárias metálicas em felídeos selvagens mantidos em cativeiro." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/10/10137/tde-20022017-100119/.
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Fraturas dentárias são enfermidades de alta prevalência entre os carnívoros selvagens, principalmente em animais cativos. Esse tipo de afecção é comum em grandes felídeos, cujos hábitos e aspectos biológicos contribuem para o traumatismo dentário. A superfície dental é capaz de suportar certo limite fisiológico de atrito e, caso esse limite seja superado, há desgaste excessivo das estruturas dentárias que pode evoluir para fratura. O tratamento preconizado envolve endodontia (tratamento de canal) e prostodontia (restauração coronal). Próteses unitárias são aquelas que restauram a coroa de um dente cuja estrutura fora parcial ou totalmente perdida. Foram cimentadas 19 (N=19) restaurações metálicas fundidas (RMF) com auxílio de cimento resinoso dual, dentre as quais, 14 (73%) mantiveram-se fixas ao dente e 5 (27%) foram perdidas, por um ou mais motivos. Em relação ao sexo, um animal era macho (11%) e os 8 demais eram fêmeas (89%). Dentre as perdas protéticas (5 = 100%), uma (20%) ocorreu em período inferior a um mês e 4 (80%) entre 9 e 14 meses. Destas, uma (20%) ocorreu em função de fratura do remanescente dentário e 4 (80%) não se sabe a causa da perda protética. Dentre as próteses mantidas (14 = 100%), um (7%) dos animais morreu durante o estudo e 13 (93%) mantem-se vivos e com as peças protéticas fixas aos dentes. Quando se trata de animais selvagens, devolver a função é o objetivo mais importante da restauração, objetivo principal deste estudoDental fractures are highly prevalent among wild carnivores, mainly in captive animals. This type of condition is common in large felids, whose habits and biological aspects contribute to dental trauma. The tooth surface is capable of supporting certain physiological limit of friction, and if this limit is exceeded, there is excessive wear of the dental structures that can lead to fracture. The recommended treatment involves endodontics (root canal treatment) and prosthodontics (coronal restoration). Unitary prostheses are those that restore the crown of a tooth which structure had been partially or completely lost. Among the 19 (N = 19) cemented prostheses in this study with dual ciment, 14 (73%) remained fixed to the tooth and 5 (27%) were lost for one or more reasons. Regarding sex, an animal was male (11%) and 8 others were females (89%). Among the prosthetic losses (5 = 100%), one (20%) occurred in less than one month and 4 (80%) between 9 and 14 months. Of these, one (20%) occurred in the remaining tooth fracture function and 4 (80%) the cause of prosthetic loss was not known. Among the retained prosthesis (14 = 100%), one (7%) of the animals died during the study and 13 (93%) are still alive and the prosthetic pieces still fixed to the teeth. When it comes to wildlife, return the function is the most important goal of the restoration, the main objective of this study
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Dias, José Manuel Carvalho. "Abordagem terapêutica do paciente bruxómano." Master's thesis, [s.n.], 2015. http://hdl.handle.net/10284/5138.
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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina DentáriaO bruxismo é uma atividade parafuncional, noturna ou diurna, caracterizada pelo ato, subconsciente e não funcional de apertar e ranger os dentes. Estima-se que a sua prevalência na população adulta ronde os 8-10%, sendo o bruxismo diurno o mais prevalente, comparativamente ao noturno e o género feminino o mais afetado por este tipo de bruxismo. O presente trabalho teve como propósito rever algumas das opções terapêuticas reabilitadoras, utilizadas nestes pacientes, e averiguar qual delas apresenta os melhores resultados clínicos, ao longo dos anos. Realizou-se uma pesquisa bibliográfica, onde se limitou o intervalo de tempo a artigos entre 2004 e 2014, tendo-se no entanto, recorrido a um artigo de 2002 e a uma tese de mestrado, que se revelaram pertinentes para a revisão em causa. Dos 36 artigos consultados, 18 correspondem a revisões bibliográficas, 18 a casos clínicos, uma tese de mestrado e 2 livros. A bibliografia revela-se inconclusiva quanto à melhor abordagem reabilitadora a seguir, focando-se nos riscos inerentes a cada reabilitação e cuidados a ter, em cada caso, mediante a opção selecionada. Sendo a escolha, principalmente baseada nas expectativas do paciente e condição económica. No entanto, sendo o bruxismo uma parafunção complexa multifatorial, parece unânime que a sua abordagem terapêutica necessite de uma equipa multidisciplinar, que permita não só a reabilitação da dentição desgastada, como uma abordagem direcionada para a diminuição dos estímulos desencadeantes, sinais e sintomas, permitindo uma maior longevidade das mesmas. No entanto, são necessários mais estudos, com desenhos e limites bem definidos, para que se consiga chegar a conclusões mais coerentes. Bruxism is a parafunctional activity which can occur during sleep as well as during wakefulness, characterized by unconscious and unfuntional teeth grinding or clenching. It’s estimated that its prevalence, in the general adult population, is about 8-10%, being the wakefulness bruxism the most prevalent and the female gender more affected. With this work we purpose to review some rehabilitative treatment options, used in these patients, and determine which had the best clinical results over the years. A literature search was performed and most of the papers selected were published between 2004- 2014, apart from one which was published before, but of additional value for our review. Of the 36 papers selected, 18 of them were review articles, 18 were clinical cases, one a master thesis and 2 books. The literature is inconclusive in determine which is the best rehabilitation option in this cases, being just stated the major risks and cautions we need to have in which of them. Moreover, the choice is mainly based on patients expectations and economic condition. As bruxism is a multifactorial parafuntional, with no specific treatment, is believed that is needed a multidisciplinary team for its management, so that the focus is not only in the type of rehabilitation but also in reduce the adverse effects of the habit. There is still insufficient evidence to support or refute a certain type of rehabilitation and treatment therefore, more studies are needed, with clear drawings and limits so that we can get more consistent and specific outcomes.
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Latief, Abduraghman. "Sorption and solubility of a denture base acrylic." Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/1533.
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Thesis submitted in fulfilment of the requirements for the degree
Master of Technology: Dental Technology
in the Faculty of Health and Wellness Sciences
at the Cape Peninsula University of Technology, 2012Statement of problem It is well documented that water sorption and water solubility by auto-polymerizing resins have a negative impact on their physical properties and may lead to harmful tissue reactions. The presence of residual monomer is often identified as the main cause for adverse tissue reactions. To optimize the polymerization reaction, the use of the proper powder/liquid ratio is recommended in the fabrication of a dental appliance. It is also recommended that a dental appliance should be soaked in water for at least 24 hours before delivery to a patient, in order to reduce the possible adverse effect. For auto-polymerizing resins, associated with higher residual monomer levels than heat-cured resins, soaking the appliance at elevated temperatures (65ºC for 60 minutes), would reduce the residual monomer content more efficiently than at room temperature. This requires additional processing conditions from the technician or dentist. Changing the powder/liquid ratios, deliberately or not, may modify the residual monomer content of the final product. A relationship exists between the levels of residual monomer and water sorption. Also, residual monomer leaching into the oral fluids may lead to adverse effects such as, oral tissue irritation or a delayed hypersensitivity reaction. Aim of the study The aim of this study was to evaluate the effect of different powder/liquid ratios and different water temperatures on the levels of sorption and solubility of an auto-polymerizing resin material used for denture bases. The null-hypothesis tested was that there is no difference in sorption and solubility among groups of specimens made from an auto-polymerizing resin material soaked in water at different temperatures and/or fabricated with different powder/liquid ratios. Material and methods Specimens were made from cold-cure pour-type denture base resin (Type 2, Class 2) using different powder/liquid ratios and soaked at different soaking temperatures. One group of specimens fabricated with the manufacturer’s recommended powder/liquid ratio and soaked in water at 37ºC, served as the control group for both experiments. Custom-made stainless steel moulds were used to fabricate resin disks, with a diameter of 50mm and a thickness of 0.5mm. For the temperature-controlled experiment, identical specimens were prepared and stored in distilled water at 37ºC; 45ºC; 55ºC and 67ºC. For the ratio-controlled experiment, the ratios were increased incrementally for each group, starting with a 10% increase, followed by a 15%; 20% and 25% increase in monomer. Water sorption and solubility were tested in accordance with ISO Standard 1567 (1999). Specimens were weighed before and after water immersion, and desiccation. Water sorption and solubility were calculated using the difference in wet and dry mass and the volume of the specimens. The water sorption and solubility results were analyzed by means of analysis of variance. For multiple comparisons, Bonferroni simultaneous confidence intervals (α=0.05) were applied. Results For the ratio-controlled experiment, water sorption mean values varied from 24.148 μg/mm3 to 25.1333 μg/mm3. Statistically significant differences in mean values were found between the following groups: 0%-10%; 0%-15%; 0%-25%; 10%-20%; 15%-20% and 20%-25% ratio groups (P<.0001). Water solubility mean values varied from 0.616μg/mm3 to 0.932μg/mm3. Statistically significant differences in mean values were found between the following groups: 0%-15%; 0%-20%; 0%-25% and 10%-25% and 20%-25% ratio groups (P<.0001). For the temperature-controlled experiment, water sorption mean values varied from 24.185μg/mm3 to 26.434μg/mm3. Statistically significant differences in mean values were found between the following groups: 37ºC-45ºC; 37ºC-55ºC; 37ºC-67ºC; 45ºC-67ºC and 55ºC-67ºC temperature-controlled experiments (P<.0001). Water solubility mean values, for the same experimental groups, varied from 0.616μg/mm3 to 2.752μg/mm3. Statistically significant differences in mean values were found among all the 6 pairs of groups (P<.0001). Despite statistical differences, the water sorption and water solubility values of the tested resin for both experiments and all groups were within the ISO Standard 1567 (1999) specification limits. Conclusion For the ratio-controlled experiment, there was an inverse relationship between the mean sorption and solubility values with an increase in liquid in the mixture: low water sorption levels are associated with high solubility levels. The lower water sorption and higher solubility results for more fluid mixtures could be related to initial and residual high monomer content characteristic of auto-polymerizing materials. These higher levels of free monomer are consequently released upon immersion in water; hence the higher water solubility levels. For the temperature-controlled experiment, a higher soaking temperature resulted in an increase in water solubility levels. The higher solubility levels could be attributed to the higher soaking temperatures causing higher or faster monomer diffusion from the resin material. Except for the 67ºC group, sorption is also lower with higher temperatures. It may be assumed that an additional polymerization process takes place and a subsequent more inaccessible polymer matrix is produced. For the 67ºC group, thermal expansion may explain the higher sorption level. Clinical Implications In terms of the sorption and solubility results, this auto-polymerizing pour-type resin may be used as a denture base resin. Even though statistical differences were demonstrated, the material satisfies the ISO 1567 (1999) requirements not only for auto-polymerizing but also for heat-polymerizing resins. Therefore, within limits, the mixture may be prepared more fluidly in order to improve flow of the material, without negatively affecting its sorption and solubility properties. Because solubility is higher at higher soaking temperatures, this property can be used to minimize monomer content of the appliance. Therefore, it is recommended that the dental appliance be soaked in warm water, below 67ºC, prior to delivery to the patient.
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Aziz, Aziz Ghanim Aziz. "The effect of Artificial Aging (LTD) on the mechanical and optical properties of conventional and translucent zirconia for fixed prosthodontics." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20790/.
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In the last two decades, zirconia has been of a great interest to dentists due to its superb mechanical and optical properties. At first, the use of zirconia was limited to fabrication of cores replacing the metal in crown construction. Nowadays, there is an increase in the trend of using monolithic ‘full contour’ translucent zirconia to overcome the problem of chipping of porcelain veneers and to overcome the limitation of using lithium disilicate in long span replacement. This has brought zirconia in direct contact with saliva and oral fluids and introduced the possibility of the material undergoing low temperature degradation. This study aimed to investigate the effect of accelerated hydrothermal aging on the mechanical and optical properties of two conventional core and two full contour translucent zirconia materials, expected to be used by 90% of zirconia manufacturers globally. Hydrothermal aging was carried out using an autoclave to simulate in vivo aging, using a specific protocol proposed by ISO 13356:2015 mimicking 15- 20 years of clinical service of the material. Each of the four materials were tested before and after aging, including structural analysis which was carried out using XRD, SEM, FIB-SEM and AFM. Mechanical property investigations were carried out by measuring BFS and Vickers hardness. Optical properties were thoroughly investigated through measuring a range of translucency parameters and changes in colour before and after aging. The results of this study showed that conventional core materials were less affected by hydrothermal aging in comparison to full contour translucent zirconia in terms of optical properties. All of the used materials showed clear colour changes after aging, however none of them showed significant changes in the mechanical properties even with more than 20% of t →m phase transformation in one of the translucent zirconia materials. Within the limitation of this in vitro study, it can be concluded that full contour translucent zirconia can be used clinically with no concern about its mechanical and optical properties, however, further studies on the perception and acceptability for changes in the optical properties would be highly recommended.
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Beavers, Charles M. "Restorative Characteristics of Intrapulpally Cracked Teeth." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3713.
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Cracked teeth have long presented a diagnostic challenge. Previous investigators have considered possible predictive factors, many of which revolve around the tooth’s restorative characteristics. Few have investigated the restorative status of teeth with cracks extending into the pulp chamber. The purpose of this investigation was to determine the prevalence of the different types of restorations present in intrapulpally cracked teeth and determine any other restorative factors that may aid in predicting the presence or extent of an intrapulpal crack. Intrapulpally cracked molars requiring endodontic therapy at the VCU Graduate Endodontic Practice were included in this study. For each tooth, the type of restorative material present and surfaces involved were recorded. The Restoration Volume Proportion (RVP) was calculated to accurately quantify the size of the restoration present. Pulpal and periapical diagnoses, and intrapulpal crack classification were also recorded. Chi squared analysis and logistic regression were used to determine any significant associations. This study included 43 teeth. The study population was 65% female and the average age was 56. Of the various restoration types evaluated, 73% of teeth presented with amalgams, 12% with composites. Class I restorations were 61% of the sample. The most frequently occurring restoration size by volume was a “small” restoration. The most commonly involved teeth were the maxillary 1st molar and mandibular 2nd molar. A significant association was found between restoration size and crack classification suggesting that teeth with larger restorations had a higher incidence of coronal cracks while those with smaller restorations had a higher incidence of radicular cracks. Restoration classification and pulpal walls involved were also significantly associated suggesting that Class II restorations were most frequently associated with cracks involving a single pulpal wall while Class I restorations were evenly associated with one and two wall cracks. Other significant associations were found between tooth type and pulpal walls involved and between restoration surfaces and pulpal wall classification. This study found several significant associations between restoration characteristics and intrapulpal cracks. Further research may continue to reveal how a tooth’s restorative status may influence its risk for the presence of an intrapulpal crack.
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Shahani, Purnima Joan. "THE BOND STRENGTH OF ADHESIVE RESIN CEMENT: TIME DIFFERENTIAL BETWEEN CEMENTATION AND FINISHING OF CAST DOWEL-CORES." VCU Scholars Compass, 2003. http://scholarscompass.vcu.edu/etd/1149.
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THE BOND STREGTH OF ADHESIVE RESIN CEMENT: TIME DIFFERENTIAL BETWEEN CEMENTATION AND FINISHING OF CAST DOWEL-CORES By Purnima Joan Shahani, D.D.S., M.S.A Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University.Virginia Commonwealth University, 2003Major Director: Peter C. Moon, M.S., PhDDirector of VCU Dental Biomaterials LaboratoryThis study compared the retention of cast dowel-cores cemented with Panavia® 21 subjected to immediate versus delayed high-speed finishing. Conventionally, finishing is delayed for 24 hours to one week to allow for optimal setting and ultimate strength of the cement. Forty-five recently extracted human maxillary canines were used. Teeth were divided among 3 groups: a control group (n=15, no finishing), an immediate finishing group (n=15, high-speed cutting of the cores performed five minutes after cementation) and a delayed finishing group (n=15, high-speed finishing performed 48 hours post-cementation). Tensile load to failure was applied using an Instron® at a crosshead speed of 0.05 inches/minute. A statistical test of equivalence was performed. The average retention force associated with failure after immediate finishing was not found to be inferior to delayed finishing failure force. In fact, post-hoc comparisons indicated that immediate finishing has statistically significant greater mean retentive force when compared to this force for delayed finishing at p = 0.00001.
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Brandt, Paul Dieter. "Shear bond strength, microleakage and anti-bacterial properties of self-etching bonding systems." Diss., Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-02182010-110040/.
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Garaicoa, Pazmino Jorge Luis. "Minimal inhibitory concentration of antimicrobial and antifungal agents in denture adhesive material against Candida albicans." Thesis, University of Iowa, 2014. https://ir.uiowa.edu/etd/1458.
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Approximately 26% of the U.S. population between the ages of 65 and 74 years are completely edentulous. Of the different proposed predictors and risk factors, low income and education levels have the highest correlation with tooth loss. While the incidence of complete edentulism in the United States has progressively declined over the past decade, the continued growth of the population strongly suggests that edentulism prevalence will likely remain constant or increase over the next few decades. In patients wearing complete prosthetic appliances, several post-treatment complications may arise, including denture associated Candida species infections and mucosal stomatitis. These type of fungal infections are associated with patient-reported symptoms (e.g. pain or discomfort) and may impede normal oral function. In this study the activity of 11 (antimicrobial and/or antifungal) agents in a dental adhesive carrier against two strains of C. albicans was assessed. In conventional minimal inhibitory concentration (MIC) assays, C. albicans were resistant to histatin 5 and lactoferricin B, yet very susceptible to SMAP28; susceptible to long chain bases sphingosine, dihydrosphingosine, and phytosphingosine; and susceptible to anti-fungal agents amphotericin B, chlorhexidine dihydrochloride, chlorhexidine gluconate, fluconazole, and nystatin. However, in 1% dental adhesive (final concentration) C. albicans were resistant to histatin 5, lactoferricin B, SMAP28, sphingosine, dihydrosphingosine, and phytosphingosine suggesting that the components in denture adhesive may inactivate local innate immune factors in the oral cavity possibly predisposing users to fungal infections in relation to their dental prostheses. In MIC assays in 1% dental adhesive (final concentration) C. albicans were susceptible (p value < 0.05) to amphotericin B, chlorhexidine, dihydrochloride, chlorhexidine gluconate, fluconazole, and nystatin strongly suggesting that these anti-fungal agents could be candidates for inclusion in denture adhesive formulations, and also be used as a prescribed topical treatment in individuals with fungal infections of the oral mucosa.
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Camargo, Sergio Luiz da Silveira. "Análise biomecânica de resistência à fratura em dentes caninos artificiais de cães, com restauração metálica fundida e retentores intrarradiculares retos e curvos com núcleo - Estudo comparativo com análise por elementos finitos." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/10/10137/tde-24052016-092307/.
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Os cães, por fatores diversos, acabam por apresentar dentes fraturados com ou sem exposição de polpa. Estas fraturas basicamente são identificadas como fraturas recuperáveis não complicadas, recuperáveis complicadas ou irrecuperáveis. As fraturas recuperáveis (localizadas apenas no esmalte e dentina) são tratadas com dentística restauradora. As recuperáveis complicadas (com lesões em esmalte, dentina e exposição do canal radicular) passam por tratamento endodôntico, podendo ser seguidas de restaurações metálicas. Os dentes mais comumente acometidos são os dentes caninos, superiores ou inferiores. Este trabalho em dentes artificiais simulando considerável destruição de sua porção coronal objetivou testar, após a adaptação da restauração metálica fundida, a resistência às fraturas no dente canino. Os dentes artificiais foram padronizados com uma técnica de replicação de raízes artificiais em molde de resina acrílica quimicamente ativada. Oitenta réplicas iguais de resina composta fotopolimerizável, padronizadas em tamanho e forma, foram construídas a partir desta técnica. Antes da reconstrução protética, aplicou-se o tratamento endodôntico, desobturação, preparo do canal radicular e moldagem. Proteticamente, um pino intrarradicular reto e outro curvo, ambos com núcleo para sustentar a coroa metálica fundida foram cimentados na porção coronal de cada raiz-réplica. Os núcleos e coroa metálica foram ambos ferulados ou estojados. Avaliou-se os dois tipos de restauração com pino intrarradicular curvos ou retos cimentados com cimento de fosfato de zinco ou resinoso para identificar o melhor conjunto restaurador. Os testes de resistência biomecânica de 80 raízes-réplicas foram divididos em 4 grupos com 20 corpos de prova para cada um dos grupos. Grupo 1: das raízes-réplicas com pino intrarradicular curvo cimentados com cimento resinoso. Grupo 2: das raízes-réplicas com pino intrarradicular curvo cimentados com cimento de fosfato de zinco. Grupo 3: das raízes-réplicas com pino intrarradicular reto cimentados com cimento resinoso. Grupo 4: das raízes-réplicas com pino intrarradicular reto cimentados com cimento de fosfato de zinco. Estes grupos foram submetidos a teste de força com pré-carga de 1,5 N, com velocidade de avanço constante de 0,05 mm por minuto em ponto pré- determinado (mésio-lateral vestibularizada) até ocorrência de fratura do conjunto ou parte dele em uma Máquina Universal Kratos. Com a avaliação biomecânica e estudo estatístico de Kruskall-Wallis, identificou-se que os dados obtidos não seguiram distribuição normal. Esta diferença mostrou-se com o p<0,05 na interpretação do teste. No caso de dados não paramétricos o post-hoc do Kruskal-Wallis foi o teste de U de Mann-Withney. Paralelamente, um estudo com análise de elementos finitos comparou os resultados obtidos. Não houve diferença significativa sobre o tipo de cimento utilizado ou que favorecesse o uso do pino reto ou do pino curvo, recaindo a escolha para o operador decidir de acordo com a melhor indicação para cada caso clínicoThe dogs, by various factors, present fractured teeth with or without pulp exposure. These fractures are basically identified as recoverable fractures not complicated, recoverable complicated or unrecoverable. Recoverable fractures (located just on enamel and dentin) are treated with restorative dentistry. The complicated recoverable (with lesions in enamel, dentin and exposure of the root canal) need to undergo endodontic treatment, and may be followed by metallic restorations. The teeth most commonly affected are the canine teeth, upper or lower. This work on artificial teeth simulating considerable destruction of their coronal portions aimed to test, after the adaptation of the cast metal restoration, the fractures in the canine teeth. Artificial teeth were standardized with an artificial root replication technique in acrylic chemically activated resin impression. Eighty equal photopolimerized composite resin replicas, standardized in size and shape, were built with this technique. Before the prosthetic reconstruction, endodontic treatment, desobturation, root canal preparation and molding were done. Protetically an intrarradicular straight pin and another curved one, both to sustain core fused metal crown were cemented over the crown of each root replica. The cores and metal crown were both belted or sheathed. It was evaluated the two types of restorations with intrarradicular curved or straight pin cemented with zinc phosphate cement or resin to identify the best restorative set. The biomechanical resistance tests applied over the 80 replica roots were divided into 4 groups with 20 samples for each of the groups. Group1: roots with intrarradicular curved pin replicas cemented with resin cement. Group 2: roots with intrarradicular curved pin replicas cemented with zinc phosphate cement. Group 3: roots intrarradicular straight pin replicas cemented with resin cement. Group 4: roots intrarradicular straight pin replicas cemented with zinc phosphate cement. These groups were submitted to the test of strength with 1.5 N preload force, with constant speed rate of 0.05 mm per minute in a predetermined point (mesio-vestibular) until occurrence of fracture of the whole set or part of it in a Universal Machine Kratos. The Biomechanical evaluation and statistical study of Kruskall-Wallis, identified that the data obtained did not follow normal distribution. That difference showed up with the p < 0.05 in the interpretation of the test. In the case of parametric data post-hoc Kruskal-Wallis test of U of Mann-Whitney. At the same time, a study with finite element analysis compared the results obtained. There was no significant difference on the type of cement used or favoring the use of straight or curved intrarradicular pin, therefore it is up to the surgeon to decide according to the best indication for each clinical case
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Pinheiro, Juliana Barchelli. "Identificação da microbiota de próteses bucomaxilofaciais e tecidos adjacentes e avaliação da efetividade antimicrobiana de diferentes protocolos de higiene e de seus efeitos sobre propriedades de dois silicones." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/58/58131/tde-07122015-092654/.
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O objetivo do presente estudo foi identificar, clinicamente, os micro-organismos presentes em próteses e tecidos adjacentes, avaliar laboratorialmente a ação antimicrobiana de diferentes protocolos de higiene sobre os principais micro-organismos identificados e, ainda, avaliar a influência dos protocolos de higiene na alteração de cor, dureza Shore A, rugosidade superficial e absorção de líquidos, de um novo silicone (Bio-Skin), em comparação ao MDX 4-4210. Para identificação dos micro-organismos, 43 indivíduos portadores de próteses maxilofaciais foram submetidos à colheita do biofilme na região da prótese e tecidos adjacentes e 38 espécies alvos de micro-organismos foram pesquisadas por meio do método de hibridação de DNA Checkerboard. A análise da ação antimicrobiana foi conduzida por meio da formação de biofilmes específicos de 6 espécies selecionadas. 288 espécimes pigmentados com pó de maquiagem foram confeccionados com cada material, e distribuídos em grupos para imersão em gluconato de clorexidina a 0,12%, Ricinus communis a 10%, e escovação com sabão neutro. Como controle, um grupo foi imerso em água. Para análise da influência dos protocolos de higienização nas propriedades dos silicones, 120 corpos de prova circulares de cada material foram confeccionados (n=10): sem pigmentação (GC: controle), com pó de maquiagem (GP), opacificador (GO) ou opacificador + pó de maquiagem (GPO), para então serem submetidos à higienização: EA (imersão em água destilada + escovação com sabão neutro controle), ERc10% (imersão em solução de Ricinus communis 10% + escovação com sabão neutro) e ECl0,12% (imersão em gluconato de clorexidina 0,12% + escovação com sabão neutro). O período de higienização simulou um ano de uso clínico. As variáveis de resposta quantitativas foram mensuradas imediatamente após a obtenção dos espécimes e após a aplicação dos protocolos de higiene e a variação obtida foi utilizada na análise estatística. Para análise da ação antimicrobiana dos protocolos de higiene e para alteração de cor, dureza Shore A e rugosidade superficial, realizou-se Análise de variância e Teste Complementar de Tukey para comparação das médias. Para a absorção de líquidos, aplicou-se o Teste de Kruskal-Wallis. Para comparação da contagem de micro-organismos presentes nas próteses e tecidos adjacentes empregou-se o Teste de Wilcoxon (Signed-rank Test). Para análise dos dados obtidos pela contagem de UFC, para análise da ação antimicrobiana dos protocolos de higiene, empregou-se Two-way ANOVA e Teste Complementar de Tukey. Todas as análises foram conduzidas com nível de significância 5%. O método de hibridação de DNA Checkerboard indicou a presença das 38 espécies nas próteses e tecidos adjacentes e foram selecionados os seguintes micro-organismos: C. glabrata, S. aureus, S. mutans, E. coli, E. faecalis e P. aeruginosa. Para a análise antimicrobiana, o gluconato de clorexidina a 0,12% foi o mais eficaz, seguido pela escovação mecânica, contra as 6 espécies. A alteração de cor não foi influenciada pelos protocolos de higiene e a menor alteração foi encontrada com o silicone Bio-Skin dos grupos GP e GPO. O silicone MDX apresentou menor variação de dureza Shore A em função do protocolo de higiene ECl0,12%, enquanto a dureza do Bio-Skin não foi influenciada pelos protocolos de higiene. A variação da dureza entre os dois silicones foi diferente somente quando submetidos ao protocolo ERc10%. Para a rugosidade superficial, o silicone MDX apresentou a menor variação de rugosidade. A porcentagem de absorção de líquidos do silicone MDX 4-4210 não foi influenciada pela pigmentação ou protocolos de higienização. Para o Bio-Skin, a porcentagem de absorção foi maior nos grupos GC e GO quando submetidos ao protocolo EA. Nota-se que houve uma interação entre pigmento e protocolo de higiene, onde para o silicone MDX, a absorção foi maior quando submetidos ao protocolo ECl0,12% e para o Bio-Skin, houve uma maior porcentagem de absorção nos grupo GC e GO associados à escovação e imersão em água e nos grupos GP e GPO associado ao protocolo ECl0,12%. Conclui-se que tanto as próteses quanto os tecidos adjacentes apresentam grande quantidade de micro-organismos colonizadores e que cuidados diários de higiene são essenciais. Os protocolos de imersão em gluconato de clorexidina a 0,12% e de escovação mecânica com sabão neutro possuem efetividade antimicrobiana sobre os principais micro-organismos comumente presentes em próteses e tecidos e o silicone MDX 4-4210 apresentou menor contagem de UFC quando comparado ao Bio-Skin. Ambos os materiais apresentaram variações em função das diferentes pigmentações e protocolos de higiene, entretanto, as mesmas foram discretas e dentro de padrões clínicos aceitáveis. As menores alterações foram observadas quando os materiais foram expostos aos protocolos de imersão em gluconato de clorexidina a 0,12% e escovação com sabão neutro.The aim of this study was to identify clinically the microorganisms present in prostheses and adjacent tissues, evaluated laboratory antimicrobial action of different hygiene protocols on the main identified microorganisms and also evaluate the influence of hygiene protocols in color change, Shore A hardness, surface roughness and absorption of liquids, a new silicon (Bio-Skin) compared to the MDX 4-4210. For identification of microorganisms, 43 individuals with maxillofacial prostheses were submitted to harvesting the biofilm on the prosthesis and adjacent tissues and 38 targets species were surveyed through the Checkerboard DNA-DNA Hybridization method. The analysis of antimicrobial activity was conducted by formation of specific biofilm in six selected species. 288 specimens with pigmented makeup powder were fabricated with each material, and divided into groups for immersion in 0.12% chlorhexidine gluconate, Ricinus communis 10%, and brushing with neutral soap. As a control, one group was immersed in water. To analyze the influence of hygiene protocols on the properties of silicones, 120 circular specimens of each material were prepared (n = 10): no pigmentation (CG: control), with makeup powder (GP), opacifier (GO) or opacifier + makeup powder (GPO), and then be submitted to cleaning: EA (immersion in distilled + brushing water with mild soap - control), ERc10% (immersion in Ricinus solution communis 10% + brushing with mild soap) and ECl0 12% (immersion in chlorhexidine gluconate 0.12% + brushing with neutral soap). The hygiene period simulated one year of clinical use. The quantitative response variables were measured immediately after obtaining the specimens and after the application of hygiene protocols and the variation obtained was used in the statistical analysis. For analysis of antimicrobial hygiene protocols and color change, Shore A hardness and surface roughness, there was analysis of variance and Tukey Supplementary test for comparison of averages. For the absorbing liquid, we applied the Kruskal-Wallis test. For comparing the count microorganisms present in prostheses and adjacents tissues we used the Wilcoxon test (Signed-rank Test). To analyze the data obtained by CFU counts for analysis of antimicrobial hygiene protocols, we used two-way ANOVA and Tukey Complementary Test. All analyzes were conducted with significance level of 5%. The method of Checkerboard DNA-DNA Hybridization indicated the presence of 38 species in the prosthesis and adjacent tissue and the following microorganisms were selected: C. glabrata, S. aureus, S. mutans, E. coli, E. faecalis and P. aeruginosa. For antimicrobial analysis, 0.12% chlorhexidine gluconate was the most effective, followed by mechanical brushing, against six species. The color change was not influenced by hygiene protocols and the slightest change was found with the Bio-Skin silicone GP and GPO groups. Silicone MDX showed less variation in Shore A hardness according to the maintenance protocol ECl0,12%, while the hardness of Bio-Skin was not influenced by hygiene protocols. The variation in hardness between the two silicones were different only when subjected to ERc10% protocol. To the surface roughness, the MDX silicone showed the smallest variation of roughness. The percentage of absorption for the MDX 4-4210 silicone was not influenced by the pigment and sanitization protocols. For the Bio-Skin, the percentage of absorption was higher in GC and GO groups when subjected to EA protocol. Note that there was an interaction between pigment and maintenance protocol, where for silicone MDX, absorption was greater when subjected to ECl0,12% protocol and Bio-Skin, there was a greater percentage absorption in the GC group and GO associated with brushing and immersion in water and GP groups and GPO associated with ECl0,12% protocol. It was concluded that both prosthesis as adjacent tissues exhibit great amount of microoorganisms colonizing and that daily hygiene are essential. The immersion in chlorhexidine gluconate 0.12% and mechanical brushing protocols with neutral soap have antimicrobial activity on the main microorganisms commonly present in prosthetics and tissue and silicone MDX 4-4210 had lower CFU counts compared to Bio Skin. Both materials showed variations due to different pigmentations and hygiene protocols, however, they were discreet and within acceptable clinical standards. Minor changes were observed when the materials were exposed to immersion protocols chlorhexidine gluconate 0.12% and brushing with neutral soap.
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Garis, David, and Christoffer Johansson. "Difference in Heat Generation Comparing “Grinding” and “Cutting” Single Crown Preparation Technique." Thesis, Umeå universitet, Institutionen för odontologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-154236.
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The main purpose of this study was to examine the difference in intrapulpal temperature (IPT) comparing a “grinding” and a “cutting” technique during single crown preparation. The difference in preparation time between the two techniques was also examined. A thermocouple was placed in the pulp chamber of 20 extracted human permanent molar teeth. The teeth were placed in a silicone model. The model was immersed in a thermostatically controlled water bath with a temperature of 37 degrees centigrade (°C), and with a water level reaching the cementoenamel junction at the teeth. For both preparation techniques an electric handpiece (NSK Ti-Max Ti85L 1:5) was used. A diamond bur was used for the “grinding” and a carbide bur for the “cutting” technique. The IPT during preparation was measured with a K-thermocouple connected to Testo 176 T4 temperature data logger. There was a significant difference in IPT rise between the two techniques for preparing the teeth. The “cutting” technique showed a higher mean temperature, 31.9 °C, compared to the “grinding”, 29.5 °C (p<0.05). Neither reached the critical value of 5.5 °C IPT increase. The “grinding” technique averaged a longer preparation time of 106 seconds per tooth than the “cutting” technique (p<0.05). Our study shows that the “cutting” technique results in a higher mean temperature but that both preparation techniques can be considered as safe in regard to IPT during single crown preparation as long as sufficient water cooling is applied.
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Pihlaja, J. (Juha). "Treatment outcome of zirconia single crowns and fixed dental prostheses." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526212029.
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Abstract Metal ceramic restorations have been used in fixed prosthodontics since the 1950s, but the lack of aesthetics, the inclination to use metal-free materials, possible allergic reactions to metals, and the high cost of high noble alloys have increased the use of all-ceramic materials. The ongoing development of ceramic materials led to the introduction of zirconia to fixed prosthodontics over a decade ago. The mechanical properties of zirconia have proven to be excellent, but the clinical outcome of conventional fixed zirconia restorations over the long term is unclear. This retrospective clinical study evaluated two- to seven-year outcomes, early complications during prosthetic treatment and short-term failures during the first year of use of zirconia single crowns and fixed dental prostheses (FDPs). The usefulness and durability of zirconia single crowns in abutment teeth of partial removable dental prostheses (RDPs) was also evaluated. The material consisted of 173 patients treated with zirconia single crowns or FDPs by undergraduate dental students between 2007 and 2010. Of these patients 94 were women and 79 men (mean age 55 years, range 18–79 years). Altogether 268 zirconia single crowns (mean 3 crowns, range 1–12 crowns per patient) had been fabricated for 88 patients and 120 zirconia FDPs (range 3–12 units, mean 4.5 units) for 102 patients. Seventeen patients had received both crown(s) and FDP(s). The results show that zirconia single crowns and FDPs are a suitable treatment alternative in fixed prosthodontics. Early complications during prosthetic treatment and short-term failures during the first year of use were few. The survival rate of the zirconia single crowns after 3.9 years (2–6 years) was 89% and the success rate was 80%. The survival rate of zirconia FDPs after 4.9 years (3–7 years) was 100% and the success rate was 89%. Zirconia single crowns perform well as abutment teeth of partial RDPs with a metal framework, but fractures in the veneering porcelain remain a problemTiivistelmä Metallokeraamisia rakenteita on käytetty kiinteässä protetiikassa 1950-luvulta lähtien, mutta puutteet estetiikassa, pyrkimys metallittomiin materiaaleihin, mahdolliset allergiset reaktiot ja jalojen metallien korkea hinta ovat lisänneet kokokeraamisten materiaalien käyttöä. Kokokeraamisten materiaalien kehitystyö on tuonut zirkonian kiinteän protetiikan materiaaliksi. Zirkonian mekaaniset ominaisuudet ovat osoittautuneet erinomaisiksi, mutta hammaskantoisten kiinteiden zirkonia-runkoisten proteesien kliiniset pitkäaikaistulokset puuttuvat. Tämän retrospektiivisen kliinisen tutkimuksen tarkoituksena oli selvittää zirkonia-runkoisten yksittäisten kruunujen ja zirkonia-runkoisten siltojen menestymistä 2–7 vuoden aikavälillä sekä kartoittaa niiden valmistuksen aikaiset ongelmat ja varhaiset epäonnistumiset ensimmäisen vuoden aikana. Lisäksi tutkittiin zirkonia-runkoisten yksittäisten kruunujen käyttökelpoisuutta ja kestävyyttä metallirunkoisten rankaproteesien tukihampaina. Materiaali koostui 173 potilaasta, joille hammaslääketieteen opiskelijat olivat tehneet zirkonia-runkoisia yksittäisiä kruunuja tai zirkonia-runkoisia siltoja vuosina 2007–2010. Potilaista 94 oli naisia ja 79 miehiä (keski-ikä 55 vuotta, jakauma 18–79 vuotta). Kaiken kaikkiaan 268 zirkonia-kruunua (keskimäärin 3 kruunua, jakauma 1–12 kruunua potilasta kohti) oli valmistettu 88 potilaalle ja 120 siltaa (keskimäärin 4,5 yksikköä, jakauma 4,5 yksikköä) 102 potilaalle. Seitsemälletoista potilaalle oli tehty sekä kruunuja että siltoja. Tulokset osoittavat, että zirkonia-runkoiset kruunut ja sillat ovat käyttökelpoisia kiinteässä protetiikassa. Valmistuksenaikaiset ongelmat ja varhaiset epäonnistumiset ovat vähäisiä. Yksittäisten kruunujen selviytymisprosentti 3,9 vuoden jälkeen (2–6 vuotta) oli 89 % ja onnistumis-prosentti 80 %. Siltojen selviytymisprosentti 4,9 vuoden jälkeen (3–7 vuotta) oli 100 % ja onnistumisprosentti 89 %. Zirkonia-runkoiset kruunut toimivat hyvin rankojen tukihampaina, mutta niiden ongelmana ovat päällepolttoposliinin lohkeamat
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Morandini, William José. "Percepção de desfechos relacionados à prótese dentária em indivíduos desdentados." Universidade Federal de Goiás, 2006. http://repositorio.bc.ufg.br/tede/handle/tede/8106.
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Self-perception of potential outcomes of prosthodontic treatment, including benefits, risks and consequences of not replacement of missing teeth, were studied in edentulous patients. Initially, using a qualitative approach, it was developed a instrument containing 41 affirmatives that comprise a scale and sub-scales that measure subject’s perception score in a 5-point Likert-type scale (1=strongly disagree; 2=disagree; 3=neutral; 4=agree; 5=strongly agree). Subsequently 126 partially or totally edentulous subjects were interviewed. Mean age was 51.8-years (SD=12.3), 74% female. Cronbach’s alfa coefficient of scale and sub-scale ranged from 0.70 and 0.90. Influence of age, gender and clinical variables were tested using analysis of variance and independent t-test. Sum of scores for each subject ranged from 123 to 198, mean score was 173.8 (SD=14.8). Subjects tended to agree with the proposed affirmatives (scores 4 and 5). Considering the total scale, lower scores were obtained by younger (p=0.033), male (p=0.019) and subjects with a single missing tooth (p=0.004). Using sub-scale of benefits, with single missing teeth subjects ranked lower scores (p=0.021). No variables showed significant relationship with perception scores using risks sub-scale. When considering sub-scale that measures perception of consequences of not replacement, lower scores were obtained by males (p=0.033), single missing tooth (p=0.018) and non wearers of prosthodontics (p=0.000). It was concluded that perception of potential outcomes of prosthodontic treatment was influenced by clinical variables. Older subjects, female, subjects with grater number of missing teeth and that have been previously treated have greater perception of benefits and risks of prosthodontic treatment.
Foi avaliada em indivíduos desdentados a percepção de desfechos potenciais relacionados a benefícios e riscos do tratamento e conseqüências do não tratamento protético. Inicialmente foi desenvolvido um instrumento com 41 afirmativas que compuseram as escalas e sub-escalas com categorias ordinais tipo-Likert de 5 pontos (1=discordo totalmente; 2=discordo; 3=neutro; 4=concordo; 5=concordo totalmente). A seguir foram entrevistados 126 indivíduos desdentados parciais ou totais, usuários ou não de prótese, idade média de 51,8 anos (DP=12,3), sendo 74% do sexo feminino. O coeficiente alfa de Cronbach da escala e sub-escalas variou entre 0,70 e 0,90. A influência da idade, sexo e dados clínicos foram avaliados através de análise de variância e teste t não pareado. A soma dos escores dos 41 itens para cada indivíduo variou entre 123 e 198, média de 173,8 (DP=14,8), com valor mínimo de 41 e valor máximo de 205. A proximidade da soma dos escores com valores máximos indicou tendência dos indivíduos em concordar com as afirmativas da escala (escores 4 e 5). Na escala total os menores escores foram para indivíduos jovens (p=0,033), do sexo masculino (p=0,019) e com espaços protéticos unitários (p=0,004). Na sub-escala de benefícios os menores escores foram para os desdentados unitários (p=0,021). Nenhumas das variáveis foram significativas para a sub-escala de riscos. Na sub-escala de conseqüências da não reposição, os menores escores foram para os homens (p=0,033), desdentados unitários (p=0,018) e não usuários de prótese (p=0,00). A percepção individual dos desfechos do tratamento protético foi influenciada por variáveis clínicas, sendo mais alta em indivíduos com maior idade, mulheres, maior número de dentes perdidos e usuários de prótese.
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Jacobs, Nicholas R. "Displacement of Screw-Retained Single Crowns into New Generation Narrow Diameter Implants with Conical and Conical/Hex Internal Connections and their Performance when Cyclically Loaded." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1566144926275455.
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Schleider, David Mark. "Effect of Storage Temperatures of Panavia F on the Retention of Prefabricated Dowels." VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd_retro/78.
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Statement of Problem. Resin-based cements have become increasingly more popular for the cementation of prefabricated endodontic dowels due to their superior retention. The manufacturer of Panavia F 2.0 suggests that the product be stored under refrigerated conditions while not in use, however, there is no literature to support such a rationale. It is possible that these storage/use temperature cycling events may have a deleterious effect on the retention of prefabricated endodontic dowels. Purpose. The purpose of this in-vitro study was to investigate the retention of Panavia F 2.0 used to lute prefabricated endodontic dowels after the Panavia F 2.0 system has been kept under different storage conditions. Material and Methods. Sixty-four extracted human central incisors were selected to undergo root canal therapy and dowel retention testing. Four separate Panavia F 2.0 cement systems were placed under 4 different storage conditions for a period of 6 months, until retention testing was initiated. In the first group, the Panavia F 2.0 was stored under the manufacturer's suggested refrigerated conditions, at a constant temperature of 40°F. In the second group, the Panavia F 2.0 was stored under a constant 90°F temperature. In the third group, the Panavia F 2.0 was stored under room temperature conditions of 70°F. The fourth group attempted to mimic clinical usage conditions with the Panavia F 2.0 being cycled from refrigeration at 40°F for 22 hours/day to 2 hours/day of room temperature at 70°F 5 days per week for the duration of the 6-month storage condition period. Results. Stress values were analyzed using 1-way ANOVA. A Tukey's HSD multiple comparison analysis of the dowel retention strengths indicated that the group stored at 90°F resulted in the lowest retention. This group was significantly lower than all other groups' retention strength (p Conclusions. Within the limitations of this study, the storage of Panavia F 2.0 at either room temperature or cycling between refrigeration and room temperature yields similar dowel retention values. However, the storage of Panavia F 2.0 at temperatures of 90°F for prolonged periods causes poor dowel retention. Clinical Implications The results of this study do not support the necessity of storing Panavia F 2.0 under refrigerated conditions between clinical uses, if used within six months. However, the storage of the Panavia F 2.0 cementation system at temperatures of 90°F for prolonged periods will affect dowel retention and is therefore not advisable.
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Aroso, Ribeiro Carlos Manuel. "Retención y desgaste de tres sistemas de "attachment" para prótesis totales mandibulares sobre implantes - Estudio in Vitro." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/401680.
Full textAbstract:
Mandibular overdentures retained by two implants are recognised as the first option for treating patients without teeth, as stated by the McGill University (Canada) in its consensus statement in 2002 and the British Society to the prosthodontics study, in your consensus statement of York, published in 2009. Compared to conventional full prosthesis, they provide greater satisfaction for the patient, greater chewing ability and preservation of the residual crest height.
Purpose: This in vitro study was investigated and compare the durability and retention capacity of 3 types of attachments. Our working hypothesis states that there is no significant retention loss in different systems "attachments" tested and used in implant supported overdentures over the time and no wear in the metal components that`s requiring replacement during the same period.
Materials and Methods: Three commercially available attachments were investigated:(Clix®: Preat Corporation, Santa Ynez, CA, United States; Dalbo-Plus®: Cendres+ Métaux, Biel/Bienne, Switzerland; Locator®: Zest Anchors,Inc ,Escondido, United States), 3 different abutments inclinations (0°, 10° and 20°) . The 72 attachments were placed in acrylic resin form and they were then subjected to mechanical testing (5400 cycles of insertion and removal) over the respective ball or Locator abutments immersed in artificial saliva at pH7 and 37°C, and retention values recorded at eight different times (at the beginning, one month, six months, a year, two years, three years, four years and five years).
Results: The results revealed that there were significant differences in the average values of insertion/removal force due to the angulation (F (2, 48) =343619, p<0.05) and the type of attachment (F (7, 48) = 23.220, p < 0.05). An analysis of the results showed that the retention average (insertion and removal) for attachments was always more in inclination of 0° than inclination of 20°.
Conclusions: All attachments were tested lose the maximum value of retention force. The abutment inclination influences the intrinsic strength value of each attachment and have effect on its durability over the period of time.Las sobredentaduras mandibulares retenidas por dos implantes son reconocidas como la primera opción de tratamiento para pacientes edéntulos, tal como recoge la Universidad McGill (Canadá) en su declaración de consenso publicada en 2002 y la sociedad británica para el estudio de la odontología protésica, en su declaración de consenso de York, publicada en 2009. Al compararlas con prótesis completas convencionales, proporcionan una mayor satisfacción del paciente, una mayor capacidad masticatoria y una preservación de altura de la cresta residual. El objetivo de este trabajo es evaluar la durabilidad y capacidad de retención de attachments a largo del tiempo en inclinación de 0°, 10° e 20° y en saliva artificial a 37°C.El diseño experimental tomó en cuenta la existencia de 3 tipos distintos de sistemas de attachments (Clix®: Preat Corporation, Santa Ynez, CA, United States; Dalbo-Plus®: Cendres+ Métaux, Biel/Bienne, Suiza; Locator®: Zest Anchors,Inc ,Escondido, United States), 3 inclinaciones diferentes y uno tipo de saliva artificial ( pH 7). Los 72 attachments fueron testados en una máquina de ensayo de fatiga durante 5400 ciclos (cinco años) y se registraron los valores de retención en ocho momentos diferentes (inicio, un mes, seis meses, un año, dos años, tres años, cuatro años, cinco años).El análisis de los resultados demostró que la media de retención (inserción y desinserción) de los attachments fue siempre mayor en inclinación de 0° do que en inclinación de 20°. Todos los attachments del estudio han perdido valor máximo de retención.La inclinación influye en el valor de la fuerza intrínseca de cada attachment y tiene influencia en su durabilidad a lo largo del tiempo.
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Abreu, Ricardo Teixeira. "Analise tridimensional da distribuição de tensões na estrutura do sistema barra/clips e interface osso/implante em função do tipo de material da barra e do desajuste vertical aos implantes." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289908.
Full textAbstract:
Orientador: Marcelo Ferraz MesquitaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Este trabalho verificou tridimensionalmente a distribuição de tensões na estrutura e interface osso/implante do sistema barra/clips sobre dois implantes osseointegrados quando influenciada pelo tipo de material da barra (Liga de Au tipo III, liga de AgPd, liga de CoCr e Ti cp) e por diferentes níveis de desajuste vertical da barra a um dos implantes (5Xm, 25Xm, 50Xm, 100Xm, 200Xm e 300Xm) utilizando a metodologia através dos elementos finitos. Com o uso do programa Rhinoceros® 3.0 (NURBS Modeling for Windows, EUA), foram modelados digitalmente dois implantes Máster Screw (Conexão, Brasil) de 10 mm de comprimento, 3,75 mm de diametro de rosca e 4,1 mm de plataforma; um sistema barra/clips com dois UCLAs sem anti-rotacional (Conexão, Brasil); e uma região anterior de mandíbula com severa reabsorção óssea. O conjunto modelado foi exportado para o programa NEiNastran® 9.0 (Noran Engineering Inc., EUA) onde foram realizadas as simulações mecânicas com carregamento de 20 N/cm durante o aperto dos parafusos de retenção da barra. Os resultados obtidos foram avaliados de forma qualitativa através do gradiente de cores das tensões de von Mises e quantitativamente através do registro de três nos que apresentaram maiores níveis de tensão, localizados na barra metálica (no 470), osso cortical (no 5581) e osso medular (no 10683). Na analise qualitativa foi possível observar uma redução de tensão localizada na porção mesial da região cervical, com aumento equivalente de tensão na porção distal da região cervical do osso cortical, osso medular e barra. Na analise quantitativa os maiores e menores níveis de tensão registrados no no 470 foram 1186 MPa no desajuste de 300Xm para a liga de CoCr e 03 MPa no desajuste de 5Xm para a liga de Au tipo III. Para o no 5581, foram registrados 255 MPa no desajuste de 5Xm para a liga de Au tipo III e 225 MPa no desajuste de 300Xm para a liga de CoCr. O no 10683 registrou 215 MPa no desajuste de 300Xm para a liga de CoCr e 201 MPa no desajuste de 5Xm para a liga de Au tipo III. Foi possível concluir que o modulo de elasticidade do material da barra e o desajuste influenciaram de forma significativa as tensões registradas na barra, sem, no entanto, apresentar grande influencia na tensão gerada na interface osso/implante
Abstract: This study evaluated the 3d stress distribution around a bar/clips overdenture system on two osseointegrated implants when influenced by bar material (type III Au alloy, AgPd alloy, cp Ti and CoCr alloy) and different vertical misfit to one of the implants (5Xm, 25Xm, 50Xm, 100Xm, 200Xm e 300Xm) using finite element methodology. Using Rhinoceros® 3.0 software (NURBS Modeling for Windows, EUA), there were digitally made two Master Screw implants (Conexao, Brazil) of 10 mm width, 3.75 mm thread diameter and 4.1 mm fit platform; a bar/clips overdenture system with two UCLAs (Conexao, Brazil); and an anterior part of a severed reabsorbed jaw. The modeled set was then exported to NEiNastran® 9.0 software (Noran Engineering Inc., EUA) where the mechanic simulations were made with the screw tightened to a torque of 20 N/cm. The obtained data were evaluated by qualitative and quantitative means. The qualitative analysis was evaluated by color scale given by the program. At this analysis waspossible to observe a stress reduction at the mesial portion of the cervical region, with equivalent raising stress of the distal portion of this same region, spongy bone and overdenture bar. The quantitative analysis was measured by von Mises stress registered on three knots that showed most stress on qualitative analysis. The three knots were located at the overdenture bar (knot 470), cortical bone (knot 5581) and spongy bone (knot 10683). The greatest and smallest stress levels recorded on knot 470 were 1186 MPa at 300Xm misfit for CoCr alloy and 03 MPa at 5Xm misfit for Au type III alloy. At knot 5581, there were registered 255 MPa at 5Xm for Au type III alloy and 225 MPa at 300Xm for CoCr alloy. The 10683 knot registered 215 MPa at 300Xm for CoCr alloy and 201 MPa at 5Xm for Au type III alloy. The elastic module of the overdenture bar and misfit influenced the stress distribution at the overdenture bar itself, although it did not have great influence at the bone/implant interface
Doutorado
Protese Dental
Doutor em Clínica Odontológica