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1
Giertsen, Elin. "Clinical and microbiological aspects of Zn2+ and detergents related to dental plaque". Oslo, Norway : University of Oslo, 1990. http://catalog.hathitrust.org/api/volumes/oclc/22443983.html.
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2
Agnew, E. C. "The effects of casein on healing and plaque formation". Thesis, [Hong Kong] : University of Hong Kong, 1986. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1232629X.
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3
Mustow, R. E. "Aspects of dental plaque development in laboratory models". Thesis, University of Bristol, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379543.
Testo completo
4
Alsaif, Aysha S. Y. A. S. "Treatment of dental plaque biofilms using photodynamic therapy". Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/18523/.
Testo completoAbstract (sommario):
BACKGROUND: Photodynamic therapy (PDT) is a treatment modality involving a dye that is activated by exposure to light of a specific wavelength in the presence of oxygen to form oxygen species causing localised damage to microorganisms. AIM: To determine the most effective bactericidal incubation and irradiation times of erythrosine-based PDT, using a tungsten filament lamp, on in vivo- formed dental plaque biofilms. MATERIALS AND METHODS: The study was a two-phase randomised controlled study consisting of in-vitro and in-situ phases. Phase-1 aimed to determine the most appropriate incubation-time using erythrosine(220μM) based-PDT on lactobacillus species grown in-vitro. Phase-2 was conducted on 18-healthy adult participants wearing intraoral appliances with human enamel slabs to collect dental plaque samples in two separate periods for use in arm-1 and arm-2. For phase-2, accumulated dental plaque samples were tested under different experimental conditions; a) Control-1 (No erythrosine, no light); b) Control-2 (+Erythrosine, no light); c) Treatment-1 (+Erythrosine, +15min continuous light); d) Treatment-2 (+Erythrosine, +30sec light pulses for 5- times separated by 1min dark periods). Incubation-times of 15min and 2min were used in arm-1 and arm-2, respectively; as adapted from the previous pilot study and phase-1. Following treatment, percentage reduction of total bacterial counts were compared between the different groups. Additionally, Confocal Laser Scanning Microscopy(CLSM) was used to investigate the effect of PDT on in vivo-formed plaque biofilms. RESULTS: Significant reductions in the percentage of total bacterial counts (~93-95%) of in vivo-formed biofilms were found when using either 2min or 15min incubation-times and applying 15min continuous light. Whereas, when applying fractionated light, there was more cell death when 15min incubation-time was used (~91%) compared with the 2min incubation-time (~64%). CLSM results supported these findings. CONCLUSION: Improving the clinical usefulness of PDT by reducing its overall treatment time seems to be promising and effective in killing in vivo- formed dental plaque biofilms.
5
Reyes, Silveyra Lupita Jocelin. "Investigations on automated methods for dental plaque detection". Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3230/.
Testo completoAbstract (sommario):
This thesis investigated different quantitative methods for dental plaque detection using digital imaging. Firstly, based on a commercially available two-tone disclosing, the concentration of the dyes in the blue disclosing solution was calculated. This blue dye was used to disclose dental plaque accumulated on natural teeth and complete upper dentures (on two different backgrounds). Digital images were acquired under visible light, in the n-IR spectrum and with a narrow band-pass interference (NIB) filter tuned to the absorption spectrum of the blue dye. The results showed that disclosing dyes and disclosed dental plaque are transparent in the n-IR spectrum whilst the NIB filter maximised the contrast of dental plaque in the images when using the blue stain. A number of computerised segmentation methods were applied to these images showed automation of dental plaque detection to identify reliable methods to quantify plaque coverage. Although minor human intervention was still required in the segmentation process, the continuous development of new software promises that full automation in plaque quantification is almost a reality. Finally, analysis of the inter- and intra-examiner reliability of the commonly used Quigley and Hein index showed moderate reliability, highlighting the need for automated, quantitative and more reproducible methodology.
6
Owens, Gareth. "In vitro caries : dental plaque formation and acidogenicity". Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/15495/.
Testo completoAbstract (sommario):
Dental caries is a significant disease world-wide and although a massive reduction in prevalence has occurred over the past 50 years, incidents of this disease persist (particularly on the occlusal or aproximal surfaces and concerning younger demographics). The main reason for the observed reduction is exposure to fluoride either though water fluoridation and delivery by dentifrice. Environmental exposure reduces incidence by incorporation into the mineral phase of the hard tissue and, as a result, increases the resistance of the enamel mineral to acid-induced demineralisation. Several mechanisms have been proposed in an attempt to explain the caries-inhibiting effects of fluoride however its influence on the balance between de- and re-mineralisation episodes appears to be the principal route by which fluorides exert their effects. Efforts geared towards the continual improvement of fluoride delivery systems have also been successful to some extent and thus further exploration shows promise of improving the anticaries efficacy further. However, a complication is met in that, in vivo, multiple factors interrelated and consequently, differences in the consortia within natural oral biofilms combined with unavoidable inter-individual variations confound clinical investigations and make the distinction between relevant aspects of the process difficult. One possible alternative strategy is the development of in vitro biological models to simulate this process to a point of reflecting the in vivo situation whilst retaining control over the parameters which are known to be crucial to the progression of the disease. To this end, the Constant-Depth Film Fermenter (CDFF) has emerged as powerful tool to potentially meet the needs of current in vitro research. However, due to the lack of an inter-disciplinary approach to multi-faceted disease process, the full potential of the CDFF has not yet been reached. Therefore, the CDFF model was applied to study of anti-caries strategies which aimed to increase the persistence of the fluorides within natural microcosm biofilms. Enamel lesions were successfully produced within this system and, using a combination of both biological and non-biological demineralisations systems, the effects of anticaries agents (calcium and fluoride) were also investigated for their effects on lesion progression or reversal. Sodium fluoride (NaF; 300 ppm F-) exposures exhibited an ambiguous response on the microbial community although definite anticaries activity. Conversely, calcium lactate pre-rinses (Ca-lactate; 100 mM) appears to possess some inhibitory activity on the biofilms produced within the model whereas a less effective anticaries activity was observed in comparison to NaF exposures alone. Thus, further investigation of the effects of Ca-lactate should be pursued. Operation of the CDFF was also further developed to meet the needs of this study and analyses were performed on an integrative basis in order to capture the physiochemical events which take place during caries lesion formation. Microcosm plaques were shown to be highly diverse with respect to their community although homology was found on the bias of their ultimate definition, cariogenicity. The synthesis of inorganic mineral reservoirs within microcosm biofilms holds great potential for augmenting the physiology of the plaque and for increasing the efficacy of fluorides for prevention of enamel demineralisation. Microcosm biofilms may also have an adaptive capacity which could result in predicable response patterns. Ultimately, a holistic approach to the study of caries within a biological context provides greater insight into the caries process than approaches which lack specific interactions for the purposes of assigning direct relationships. With the successful development of a fully functional enamel caries model, the possibilities are endless.
7
Saunders, Kay Amanda. "Modelling dental plaque interactions of defined communities of oral organisms". Thesis, University of the West of England, Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283387.
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8
Gafan, Gavin Peter. "A community analysis of dental plaque in pre-pubertal children". Thesis, University College London (University of London), 2007. http://discovery.ucl.ac.uk/1445496/.
Testo completoAbstract (sommario):
Healthy children, aged between 5 and 9 years who had not taken antibiotics in the preceding three months were recruited. Plaque was sampled from the gingival crevice of either the lower left or lower right first permanent molar to estimate the prevalence of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Tannerella forsythensis which have been implicated as main etiological agents of periodontal disease. Analysis of plaque from subjects without gingivitis (n = 65) and those with gingivitis (n = 53) by PCR targeting of the 16S rRNA gene demonstrated negligible differences in the prevalence of these pathogens with the exception of T. forsythensis. This pathogen was detected more frequently in children with no gingivitis (P = 0.03). Community analysis of plaque was carried out to determine (i) any significant differences in the microbiota of both cohorts and (ii) if specific taxa influenced the prevalence of the three periodontal pathogens. Community analysis was attempted by using both culture dependent and culture independent techniques. The culture dependent technique involved community level physiological profiling (CLPP) and attempted to measure metabolic differences between cohorts. Preliminary studies demonstrated that this technique was not suitable for small sample volumes, such as plaque from single sites and was abandoned. The culture independent technique, denaturing gradient gel electrophoresis (DGGE), is a rapid and cost effective method for analysing bacterial communities. Statistical analysis of the DGGE data for both cohorts suggested that bacterial diversity was lower in subjects with gingivitis (P = 0.009). Logistic regression analysis of the DGGE banding patterns demonstrated that specific bands were significantly associated with gingival health and with gingivitis. Similarly, other bands were significantly associated with the prevalence of the three periodontal pathogens. These bands were excised and PCR-cloned. The 16S rRNA sequence data for these clones demonstrated that these DGGE bands were mixed with DNA of multiple taxa. Further attempts to separate individual excised bands over shorter denaturing gradients proved unsuccessful. This work has demonstrated that P. gingivalis, A. actinomycetemcomitans and T. forsythensis are present in the dental plaque of pre-pubertal children both with and without gingivitis. It has also provided valuable insights into the applications and limitations of fingerprinting techniques such as CLPP and DGGE.
9
Ramberg, Per. "Studies on d̲e̲ n̲o̲v̲o̲ plaque formation in man". Göteborg : Dept. of Periodontology, Faculty of Odontology, Göteborg University, 1995. http://books.google.com/books?id=Zko0AAAAIAAJ.
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10
Albert, Jeremy M. "Clinical evaluation of the Prophy-Jet in routine plaque debridement of orthodontic patients". [Gainesville, Fla.]: University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000627.
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11
Zaura, Egija. "Plaque stagnation sites and dental caries studies on dental biofilm and dentin demineralization in narrow grooves /". [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/86069.
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12
Hsu, Kuei-Ling C. "Variability of two sampling methods in plaque samples". Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008m/hsu.pdf.
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13
Eckley, Brett. "A microbiological and clinical assessment of orthodontic patients with poor oral hygiene". Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=79.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains ix, 108 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 63-67).
14
Abukhres, Omar Mohamed Omar. "Microaerophilic gram-negative rods in periodontal disease". Thesis, University of Glasgow, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320280.
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15
Jarrar, Ahmed Ali. "Comparison of an essential oil mouth rinse and chlorhexidine on 4-day interproximal plaque regrowth". Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1346_1210745930.
Testo completoAbstract (sommario):
Dental plaque is the most important etiological factor of periodontal diseases. Mechanical plaque control is the most effective way in preventing periodontal diseases. Chemical plaque control methods (such as mouthrinses) have been recommended to be used because of some drawbacks in the mechanical methods in some areas of the dentition (such as interproximal areas). But are these mouthrinses really effective in those areas? The aim of this study was to compare the effectiveness of Essential Oils mouthrinse (Listerine) on plaque formation in interproximal areas with Chlorhexidine and Sterile water.
16
Nguỹên, Thành Thi. "A three month study on the effect of chlorhexidine mouthrinse in the plaque control program of elderly patients in California". CSUSB ScholarWorks, 1987. https://scholarworks.lib.csusb.edu/etd-project/394.
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17
Kiklis, Zoe. "Chemical Dental Plaque Control: Chlorhexidine Tooth Staining and Efficacy of Common Whitening Procedures". Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/scripps_theses/336.
Testo completoAbstract (sommario):
Chlorhexidine mouth rinses remove dental plaque from teeth, preventing dental caries, dental decay, and more serious systemic infections. Tooth discoloration due to extrinsic staining is the most prominent side effect of regular chlorhexidine use. Decreasing the concentration of chlorhexidine reduces staining area and severity. Staining can also be prevented and treated by tooth bleaching, a common cosmetic dental procedure that diminishes extrinsic staining by oxidizing chromagens adsorbed onto the tooth surface. In the proposed trial, common bleaching agents will be investigated for their efficacies in preventing chlorhexidine staining. Results of the trial could further the development of a chlorhexidine mouth rinse that is suitable for long term use.
18
Claydon, Nicholas C. A. "Development and application of methods to study plaque control by dental health products". Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324269.
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19
Pang, Kam-man. "The bacteriology, structure and composition of black stains on human permanent teeth in Hong Kong". [Hong Kong] : The University of Hong Kong, 1995. http://sunzi.lib.hku.hk/HKUTO/record/B38627966.
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20
Dahmer, Heidi L. "The effects of toothbrush design on bacterial retention and viability a preliminary study /". Morgantown, W. Va. : [West Virginia University Libraries], 1998. http://etd.wvu.edu/templates/showETD.cfm?recnum=308.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 1998.Title from document title page. Document formatted into pages; contains vii, 72 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 56-58).
21
Tam, Oi-wo Joyce. "Therapeutic effects of 0.12% chlorhexidine digluconate (Peridex®) in subjects with untreated gingivitis and presence of abundant calculus". Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B16506911.
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22
Buchanan, Susan. "Effect Of Chemical Agents On Acid Production In, And The Microbial Content Of, Pits And Fissures". Thesis, The University of Sydney, 1988. http://hdl.handle.net/2123/4967.
Testo completoAbstract (sommario):
Master of Dental SurgeryThis 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
23
Buchanan, Susan. "Effect Of Chemical Agents On Acid Production In, And The Microbial Content Of, Pits And Fissures". University of Sydney, 1988. http://hdl.handle.net/2123/4967.
Testo completoAbstract (sommario):
Master of Dental SurgeryThis 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
24
Gholami, Babaahmady Kaboutar. "Variations in microflora of dental plaque at defined sub-site on approximal tooth surfaces". Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244676.
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25
Higham, S. M. "Studies in the relationship between pH, carbohydrate and nitrogen metabolism in human dental plaque". Thesis, University of Liverpool, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382064.
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26
Dodds, M. W. J. "Plaque metabolism, diet and fluoride in relation to the de- and remineralisation of dental enamel". Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381285.
Testo completo
27
Engström, Kristina. "Fluoride concentration in plaque and saliva and its effects on oral ecology after intake of fluoridated milk /". Umeå : Univ, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1542.
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28
Wallman, Catarina. "On mutans streptococci in margins of restorations". Göteborg, [Sweden] : Dept. of Cariology, Faculty of Odontology, Göteborg University, 1994. http://catalog.hathitrust.org/api/volumes/oclc/32080686.html.
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29
Song, Donna D. "The properties of the recombinant fructosyltransferase of streptococcus salivarius". Thesis, The University of Sydney, 1999. http://hdl.handle.net/2123/4937.
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30
Preston, Antony James. "The determination of dental plaque pH in the evaluation of dentrifice components in human subjects". Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283062.
Testo completo
31
Sadeq, Amal. "The effect of fixed orthodontic brackets on the bacterial composition of dental plaque in adolescents". Thesis, University of Liverpool, 2011. http://livrepository.liverpool.ac.uk/3997/.
Testo completoAbstract (sommario):
BACKGROUND: Demineralisation around orthodontic brackets is a considerable risk of orthodontic treatment. It can occur very early during treatment and involve a large number of teeth with aesthetic and dental health consequences. Early detection of demineralisation is very important in terms of treatment and prevention. The presence of bacteria is one of the requirements for demineralisation to take place and it is unclear whether the type of bacteria in the plaque or the quantity of certain types of bacteria are significant influences on demineralisation. AIM: To identify any general changes in the bacterial composition of dental plaque in adolescents undergoing fixed orthodontic appliance therapy. A secondary aim is to determine the incidence of white spot lesion development and if this was related to the identified red fluorescent plaque. STUDY DESIGN: Prospective longitudinal cohort study. METHODS: Fourteen 11 to 23 year old consecutive patients attending the Orthodontic Department of Liverpool University Dental Hospital were recruited for this study. ToothcareTM and QLF were used to identify red fluorescent plaque and enamel demineralisation on the labial surfaces of the anterior teeth before and after the placement of fixed orthodontic appliances. The bacterial composition of the red fluorescent supragingival plaque was determined by DNA extraction, polymerase chain reaction amplification of the 16r rRNA gene and denaturing gradient gel electrophoresis. 13 RESULTS: The incidence of white spot lesions was recorded as 4.2% of the total surfaces of the teeth included as detected with QLF, the development of white spot lesions was not associated with the presence of red fluorescent plaque. There were differences in the bacterial composition of red fluorescent supragingival plaque in terms of P. gingivalis, S. mutans and S. gordonii between different participants, although changes in the plaque composition between visits for the same participant was not significantly associated with the development of white spot lesions in adolescents. CONCLUSIONS: With the limitations of this study, the placement of fixed orthodontic brackets in adolescents does not significantly change the bacterial composition of red fluorescent supragingival plaque around the brackets and that the development of white spot lesions cannot be correlated to red fluorescent plaque alone.
32
Fernandes, Clarissa Pessoa. "Molecular analysis of oral bacteria in dental biofilm and atherosclerotic plaques of patients with vascular disease". Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9568.
Testo completoAbstract (sommario):
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorOver the past few years, the involvement between oral pathogens and vascular disease has been investigated, with growing attention to the pathogenesis and progression of atherosclerosis. Oral bacteria have been detected in atherosclerotic plaques at a variable frequency; however, the connection between oral health and vascular and oral bacterial profiles of these patients is not clearly established. The aim of this study was to evaluate the presence of oral bacteria DNA in the mouth and atherosclerotic plaques, in addition to assess the patientâs caries and periodontal disease history. Thirty samples of supragingival and subgingival plaque, saliva and atherosclerotic plaques of 13 patients with carotid stenosis or aortic aneurysm were evaluated, through Real Time Polymerase Chain Reaction, for the presence/absence of Streptococcus mutans, Prevotella intermedia, Porphyromonas gingivalis and Treponema denticola. For edentulous patients, the variables of supragingival and subgingival plaques were not considered. All patients were submitted to oral exams using the DMTF (decayed, missing and filled teeth) and PSR (Periodontal Screening and Recording) indexes for dental and periodontal evaluation, respectively, and histopathological analysis of the atherosclerotic plaques was performed. Most of the patients were edentulous (76.9%). Streptococcus mutans, Prevotella intermedia, Porphyromonas gingivalis and Treponema denticola were detected in 100.0%, 92.0%, 15.3% and 30.7% of the oral samples, respectively. Streptococcus mutans was the most prevalent targeted bacteria in atherosclerotic plaques (p<0,05), detected in 100% of the samples, followed by Prevotella intermedia (7.1%), and the vascular samples were negative for Porphyromonas gingivalis and Treponema denticola. There was a statistically significant difference (p<0,05) between the presence of Porphyromonas gingivalis and Treponema denticola in the oral cavity and vascular samples. In conclusion, Streptococcus mutans was found at a high frequency in oral and vascular samples, even in edentulous patients, and its presence in atherosclerotic plaques suggests the possible involvement of this bacteria with the disease progression.
Nos Ãltimos anos, a relaÃÃo entre patÃgenos orais e doenÃa vascular tem sido investigada, com crescente atenÃÃo para a etiopatogÃnese e progressÃo da aterosclerose. BactÃrias orais tÃm sido detectadas em placas aterosclerÃticas, com variÃvel frequÃncia, porÃm, a relaÃÃo entre saÃde bucal e perfis bacterianos vasculares e orais dos pacientes nÃo està claramente estabelecida. Foi objetivo deste estudo avaliar a presenÃa de DNA de bactÃrias orais na boca e placas aterosclerÃticas, alÃm de avaliar histÃrico de cÃrie e doenÃa periodontal dos pacientes. Trinta amostras de placa dental supragengival, subgengival, saliva, e placas aterosclerÃticas de 13 pacientes com estenose de carÃtida ou aneurisma de aorta foram avaliadas, atravÃs de ReaÃÃo em Cadeia da Polimerase em Tempo Real, para presenÃa/ausÃncia de Streptococcus mutans, Prevotella intermedia, Porphyromonas gingivalis e Treponema denticola. Para pacientes desdentados totais, nÃo foram consideradas as variÃveis de placa supragengival e subgengival. Todos os pacientes foram submetidos a exames de CPO-D (dentes permanentes cariados, perdidos e obturados) e PSR (registro periodontal simplificado) para avaliaÃÃo dentÃria e periodontal, respectivamente, bem como anÃlise histopatolÃgica das placas aterosclerÃticas. A maioria dos pacientes eram edÃntulos (76,9%). Streptococcus mutans, Prevotella intermedia, Porphyromonas gingivalis e Treponema denticola foram detectados em 100,0%, 92,0%, 15,3% e 30,7% das amostras orais, respectivamente. O micro-organismo mais prevalente em placas aterosclerÃticas foi o Streptococcus mutans (p<0,05), presente em 100,0% das amostras, seguido de Prevotella intermedia (7,1%), e as amostras vasculares foram negativas para Porphyromonas gingivalis e Treponema denticola. Observou-se diferenÃa estatisticamente significante (p<0,05) com relaÃÃo à presenÃa de Porphyromonas gingivalis e Treponema denticola em cavidade oral e amostra vascular. Em conclusÃo, Streptococcus mutans foi encontrado em alta frequÃncia em amostras orais e vasculares, mesmo de pacientes desdentados, e sua presenÃa em placas aterosclerÃticas sugere o possÃvel envolvimento desse patÃgeno na progressÃo da doenÃa.
33
Hale, John D. F., e n/a. "Small bacteriocins produced by Streptococcus mutans and Streptococcus sanguis". University of Otago. Department of Microbiology & Immunology, 2006. http://adt.otago.ac.nz./public/adt-NZDU20060905.144149.
Testo completoAbstract (sommario):
Dental caries is the most common bacterial disease of humans and occurs when oral bacteria produce acids, following their fermentation of dietary carbohydrates. This acid can then cause a localised demineralisation of the tooth surface. A group of seven species of bacteria, collectively known as the mutans streptococci, have been predominantly implicated in the onset of dental caries. In particular, Streptococcus mutans and Streptococcus sobrinus have been shown to be the main aetiological agents of this disease in humans. Most attempts to control the microbial component of caries target these bacteria.
The past 50 years has provided considerable information about the pathogenesis of dental caries, the likely route and time of transmission of cariogenic bacteria to susceptible hosts and possible ways of either treating or controlling the onset of this disease. In regards to the latter, many techniques (such as the use of tooth brushes, mouth washes, dental floss and tooth paste) for the control of plaque build-up exist and the examples listed are generally part of a daily routine. However, these techniques need to be applied regularly, and as such only highly-motivated individuals generally experience improved oral health. Therefore, the search for more effective less labour-intensive approaches continues. One area of research is into the potential application of small ribosomally-synthesised antimicrobial peptides, known as bacteriocins. Bacteriocins generally inhibit closely-related species that occupy the same ecological niche. Their relatively-specific targeting, plus the fact that many are remarkably heat and chemically-stable molecules, makes them excellent candidates for possible anti-caries applications.
Numerous bacteriocins produced by the lactic acid bacteria have now been identified. Most can be broadly categorised into one of four main classes, of which Class I, the lantibiotics and Class II, the small (<10 kDa) non-modified peptides, contain the most examples. Many screens for anti-mutans streptococcal (MS) bacteriocins have been carried out and it appears that the best source of anti-MS bacteriocins are the mutans streptococci themselves. Research in this laboratory has identified examples of anti-mutans streptococcal bacteriocins produced by both mutans streptococci and non-mutans streptococci. The present study investigated the anti-MS inhibitors produced by two streptococcal strains, S. mutans N and Streptococcus sanguis K11. During the course of this study a third strain, S. mutans UA159, was also studied for its bacteriocinogenic properties.
Although S. sanguis K11 produces anti-mutans streptococcal inhibitory activity, this appears only effective against Streptococcus rattus. In addition however, the inhibitory activity of this strain is also directed against all tested strains of Streptococcus agalactiae and ca. 50% of Streptococcus pyogenes. In the present study a 5069 Da novel inhibitory agent (sanguicin K11) was characterised and shown responsible for this unusual inhibitory spectrum. Through reverse genetics the sanK11 locus was identified and shown to encode a Class II type bacteriocin, the first shown to be produced by S. sanguis. Following screens of additional S. sanguis, sanK11 was shown to be present only in strains producing the same type of inhibitory pattern (P-type) as strain K11. The cysteine residues at positions 7 and 38 of the sanguicin K11 propeptide were shown to form a disulphide bridge essential for sanguicin K11 inhibitory activity.
S. mutans N and eight other S. mutans strains have been found to have what appears to be the same inhibitory spectrum, which includes members of the mutans streptococci and several other oral streptococcal species. One strain (UA140) of the eight has previously been shown to produce the lantibiotic mutacin I and the non-lantibiotic mutacin IV. S. mutans N was known to produce the non-lantibiotic mutacin N. The current study set out to investigate how two strains, apparently producing completely different bacteriocins could have the same inhibitory spectrum. Reverse genetics identified the mutacin N structural gene (mutN) and mutagenesis studies showed that this bacteriocin was responsible only for the inhibitory activity against mutans streptococci. Further sequencing around the mutN locus identified a second bacteriocin-like locus (mutO) adjacent to mutN. mutO was also identified to have anti-mutans streptococcal inhibitory activity and because of the close proximity of mutO and mutN and given the homology they share with other known two-peptide bacteriocins it seemed probable that mutacins O and N are components of a new member of this special class of bacteriocins (Class IIb, the two peptide bacteriocins) in which the optimal inhibitory activity is dependent on the co-operative activity of the two peptides.
Further investigations of strain N examined the expression of mutacins O and N. During a search for a suitable heterologous non-mutacinogenic S. mutans strain to act as an expression host, the genome reference strain, S. mutans UA159 was given consideration. However, contrary to previous reports, this strain was found to exhibit bacteriocin-like inhibitory activity. During a follow-up investigation, strain UA159 was found to inhibit 84 strains representing 11 different species of bacteria, but no inhibition of mutans streptococci was detected. The locus (nlmAB) encoding the two-peptide bacteriocin mutacin IV was identified within the UA159 genome. Using genetic dissection of nlmA and nlmB, the contribution of each peptide was examined and it was found that only the NlmA* propeptide appears to be active, raising doubts as to whether mutacin IV is a bona fide two-peptide bacteriocin. Deletion of the entire nlmAB locus created a mutant strain that exhibited a loss of inhibitory activity against the same 64 strains as was found for the nlmA mutant. A BLASTP search for the consensus leader sequence that precedes the propeptide of Class II bacteriocins, identified ORFs encoding 9 more putative bacteriocin-like peptides. Further genetic dissection identified the SMU.1914c locus as being responsible for the inhibitory activity against a further 15 strains not already sensitive to mutacin IV. SMU.1914c was renamed mutacin V. However, it appears that another as yet unidentified mutacin(s) is also produced by strain UA159 given that three indicator strains still remained sensitive to a double mutant [UA[Delta](1914/NlmAB)] in which both the mutacin IV and putative mutacin V loci were inactivated.
Export of Class II bacteriocins has been found to occur by either a SEC-dependent system or via a dedicated peptide ATP Binding Cassette (ABC) transporter. Three potential ABC transporter ORFs were identified in S. mutans UA159. Two (comA and cslA) had the characteristic accessory factor ORF (comB and cslB respectively) located adjacent to the main ABC transporter ORF, while the third ORF763 appeared to lack this. Mutagenesis of each of these five ORFS was carried out and confirmed cslAB to be the ABC transporter involved in the export of the competence stimulating factor, while the function of ORF763 could not be established in this study. Mutagenesis of either comA or comB resulted in a complete cessation of bacteriocin production by the respective mutant strains. Historically, comA and comB is the nomenclature used for loci encoding the exporter of the competence inducing factors in streptococci. In light of this new information, comA and comB were renamed nlmT and nlmE respectively, to account for the newly defined role of this ABC transporter.
The present study investigated four bacteriocins two of which (sanguicin K11 and mutacin ON) appear to have some potential for application to anti-caries control, and the others (mutacins IV and V) being shown to be produced by the genome reference strain (UA159). All three mutacins were shown to be exported from their respective producer cells by the NlmTE ABC transporter, while sanguicin K11 is predicted to be exported by a peptide ABC transporter located adjacent to sanK11.
Bacteriocins may yet provide a novel alternative for the treatment and control of dental caries. In their favour is that fact that they have relatively narrow defined inhibitory spectra and thus are unlikely to produce widespread changes to plaque ecosystems. Potential uses include as topical agents where bacteriocin preparations could be incorporated into dentrifices such as toothpastes or mouthwashes. Alternatively, streptococci producing anti-mutans streptococcal bacteriocins could be implanted into the oral cavity in strain replacement therapy strategies. There are pros and cons to each technique and the most effective anti-caries control appears more likely to result from "cocktail therapy" where bacteriocins are combined with a number of other anti-mutans streptococcal agents to achieve long-lasting protection against mutans streptococcus proliferation.
34
Tam, Oi-wo Joyce, e 譚愛和. "Therapeutic effects of 0.12% chlorhexidine digluconate (Peridex®) in subjects with untreated gingivitis and presence of abundant calculus". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31953992.
Testo completo
35
Kharel, Aayush Theerathavaj Srithavaj. "Effect of sodium bicarbonate rinses on dental plaque pH and selective oral micro-organisms in radiated head and neck cancer patients /". Abstract, 2008. http://mulinet3.li.mahidol.ac.th/thesis/2551/cd415/4838052.pdf.
Testo completo
36
Scourfield, Melanie A. "An investigation into the structure and function on model dental plaque communities using a laboratory film fermenter". Thesis, Cardiff University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337309.
Testo completo
37
Smith, Richard N. "The development of a novel method for the measurement of dental plaque area and gingival inflammation". Thesis, University of Sheffield, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412145.
Testo completo
38
Chong, Adeline Yang Li. "The effects of chlorhexidine containing toothpastes and tea tree oil containing mouthwashes on plaque and gingival inflammation : a thesis submitted in partial fulfilment for the degree of Masters [sic] of Dental Surgery (Periodontics)". Title page, contents and summary only, 1999. http://web4.library.adelaide.edu.au/theses/09DM/09dmc548.pdf.
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39
Francisco, Silvana Boldrini. "Estudo in situ da relação entre a frequencia de exposição a sacarose, carie em esmalte dental humano e contagem de estreptococos do "grupo mutans" na placa dental". [s.n.], 1995. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289263.
Testo completoAbstract (sommario):
Orientador: Jaime A. CuryDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-07-20T23:52:17Z (GMT). No. of bitstreams: 1 Francisco_SilvanaBoldrini_M.pdf: 3138517 bytes, checksum: a1bb2ce7be4f4878c9a338e809913f4b (MD5) Previous issue date: 1995
Resumo: As relações quantitativas entre frequência do consumo de sacarose, cárie dental e contagem de Estreptococos do "grupo mutans" não estão bem estabelecidos. Assim, foi realizado um estudo in situ utilizando-se um delineamento experimental do tipo cnlzado (4x4) em 04 etapas de 28 dias. doze voluntários usando dispositivos intra-orais palatinos, contendo 04 blocos de esmalte dental humano (3x3 mm), participaram desta pesquisa. Os voluntários gotejaram sobre os blocos dentais solução de sacarose a 20% na freqüência de 0 (zero) a 8x/dia. Os blocos dentais estavam protegidos por uma tela plástica e os voluntários utilizaram para sua higiene bucal dentifrício não fluoretado, mas a água consumida pelos mesmos era fluoretada (0.70 ppm). Após cada etapa a placa dental formada sobre os blocos foi coletada, pesada, homogeneizada e analisada em termos de contagem de Estreptococos do "grupo mutans" (UFC/mg) usando meio seletivo SB20. Os blocos dentais limpos, embutidos, seccionados e polidos para a determinação da dureza Knoop (KHN) do esmalte. Foram feitas indentações a 10 'mu'm de superfície utilizando microdurômetro SHIMADZU HM 2000 e carga de 25 g por 30 segundos. Os resultados microbiológicos observados em termos de média + desvio padrão da média de UFC/mg foram respectivamente em relação a exposição a sacarose de 0 (zero), 2, 4, 8x/dia: 26,72 '+ ou ¿' 13,36A; 46,72 '+ ou ¿' 30,81A; 102,44 '+ ou ¿' 53,34A e 52,18 '+ ou ¿' 21;48A, sendo que médias seguidas de mesma letra não diferem estatisticamente a nível de 5%. Quanto a dureza do esmalte diferenças significativas (p<0,05) com relação a área total só foram observadas quando a exposição a sacarose 8x/dia, resultado este semelhante quando se analisa a cada distância da superfície dental. Conclui-se que perdas de mineral só foram significativas quando da exposição a sacarose 8x/dia, não havendo entretanto relação com a contagem de Estreptococos do "grupo mutans"
Abstract: The quantitative relationship among frequency of sucrose intake, dental caries and S. mutans counts are not well established. Therefore, it was performed an in situ study utilizing an experimental design of the crossover type (4x4) in four phases of 28 days. Twelve volunteers using intra-oral palatal appliances, containing 4 blocks of human dental enamel (3x3 mm) participated in this research. The volunteers dropped on the dental blocks, 20% sucrose solution in a frequency from 0 (zero) to 8x/day. The dental blocks were protected by a plastic cover and the volunteers used for their bucal hygiene, non fluoridated dentifrice, but the water consumed by them was fluoridated (0.70 ppm). After each phase, the dental plaque formed on the blocks was collected, weighed, homogenized and assessed for S. mutans count (CFU/mg) using selective media. The dental blocks were clean, embedded, cut and polished to the Knoop hardness determination (KHN) of the enamel. It was done indentations at 10 'mu¿m of the surface using SHIMADZU H 2000 microhardness tester and 25 g load for 30 sec. The microbiological results in average '+ or ¿' standard deviation of the media of CFU/mg were, respectively in relation to the sucrose exposure of 0 (zero), 2, 4, 8x/day: 26.72 '+ or ¿'13.36A; 46.72 '+ or ¿' 30.81A; 102.44 '+ or ¿'53.34A and 52.18 '+ or - ' 21.48A . The media followed by the same letter are not statistically different at the 5% level. In the enamel hardness test, significative differences (p<0.05) in relation to the total area only were observed when the sucrose exposure was 8x/day, similar results were obtained when we assessed at each distance the dental surface. We can conclude that mineral loss only was significative when the sucrose exposure was 8x/day, although there was not a relationship to the S. mutans counts
Mestrado
Biologia e Patologia Buco-Dental
Mestre em Odontologia
40
Tenuta, Livia Maria Andaló 1976. "Concentração e cinetica de calcio, fosforo inorganico e fluoreto no fluido do biofilme dental formado na presença de sacarose". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289306.
Testo completoAbstract (sommario):
Orientador: Jaime Aparecido CuryTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-05T09:01:43Z (GMT). No. of bitstreams: 1 Tenuta_LiviaMariaAndalo_D.pdf: 3073546 bytes, checksum: e24c70c215a3d40daed4235833fee35c (MD5) Previous issue date: 2005
Resumo: O biofilme dental formado na presença de sacarose apresenta matriz com alta concentração de polissacarídeos extracelulares (PEC) insolúveis e baixa concentração de cálcio (Ca), fósforo inorgânico (Pi) e fluoreto (F). O objetivo deste estudo foi avaliar a concentração desses íons no fluido do biofilme, onde ocorrem as trocas iônicas entre o biofilme e o mineral do dente, bem como sua cinética após a ingestão de açúcar ou após a interrupção dos desafios cariogênicos. Dezesseis voluntários utilizaram em 3 fases cruzadas de 15 dias, um dispositivo palatino contendo 8 blocos de esmalte humano, que foram expostos 8 vezes ao dia a água destilada deionizada (ADD), solução de glicose a 10% + frutose a 10% (GF) ou solução de sacarose a 20% (S). Após 14 dias os tratamentos com ADD ou os carboidratos foram invertidos. As variáveis analisadas foram acidogenicidade do biofilme (pH), Ca, Pi e F no fluido e no biofilme total (após 10 h de jejum, 5 min após desafio acidogênico por solução de glicose a 20% ou após a inversão dos tratamentos), e PEC insolúveis e polissacarídeos intracelulares (IP) no biofilme total. O pH do biofilme em repouso foi significativamente menor e a concentração de IP significativamente maior (p<0,05) para os grupos GF e S em comparação com o grupo ADD. Após o desafio cariogênico, uma diminuição significante (p<0,05) no pH foi observada para todos os grupos, sem diferença entre o pH5min para os grupos GF e S (p>0,05). As concentrações de Ca, Pi e F no biofilme total foram menores para os grupos GF e S do que para o grupo ADD (p<0,05), mas esse efeito não foi observado no fluido. Após o desafio cariogênico, Ca aumentou e Pi diminuiu significativamente no fluido (p<0,05), mas o F não se alterou (p>0,05). Ca, Pi e F no biofilme total aumentaram significativamente 24 h após a suspensão do tratamento com GF (p<0,05), e o mesmo efeito foi observado para o Ca após a suspensão do tratamento S, mas essas alterações não foram observadas no fluido (p>0,05). A concentração de PEC insolúveis foi significativamente maior para o grupo S em relação aos demais grupos (p<0,05). Os resultados sugerem que as mudanças induzidas pela sacarose ou seus monossacarídeos constituintes no biofilme total não se refletem no fluido do biofilme
Abstract: Dental biofilm formed in presence of sucrose presents in its matrix high concentration of insoluble extracellular polysaccharides (EPS) and low concentration of calcium (Ca), inorganic phosphorus (Pi) and fluoride (F). However, in the fluid of the biofilm formed in presence of sucrose, either the concentration of these ions or their mobilization soon after sugar ingestion or time after the interruption of sugar exposure are unknown. Sixteen volunteers wore, for 3 crossover phases of 15 days, a palatal appliance with 8 enamel blocks, which were exposed 8 times/day to deionized water (DW), 10% glucose + 10% fructose (GF) or 20% sucrose (S) solutions. After 14 days, treatments with DW or the carbohydrates were inverted. Variables analyzed were biofilm acidogenicity (pH), Ca, Pi and F, in the fluid and in whole biofilm (after 10-h fasting, 5 min after an acidogenic challenge by 20% glucose, or after inversion of treatments), and insoluble EPS and intracellular polysaccharides (IP) in whole biofilm. Resting biofilm pH was significantly lower and IP was significantly higher (p<0.05) for GF and S groups in comparison with DW group. After the sugar challenge a significant decrease (p<0.05) in pH was observed for all groups, without significant differences between GF and S groups in the pH5min (p>0.05). Ca, Pi and F in the whole biofilm were lower in the groups GF and S than in DW (p<0.05) but this effect was not observed in the fluid. After the cariogenic challenge, Ca in the fluid increased and Pi decreased significantly (p<0.05), but F did not change (p>0.05). Ca, Pi and F in whole biofilm increased significantly 24 h after suspending the GF treatment, and Ca increased after suspending the S treatment (p<0.05), but this was not observed in the fluid (p>0.05). The insoluble EPS were significantly higher in the group S than in groups GF and DW (p<0.05). The findings suggest that the changes induced by sucrose or its component monosaccharides in the whole biofilm do not reflect in the biofilm fluid
Doutorado
Cariologia
Doutor em Odontologia
41
彭錦文 e Kam-man Pang. "The bacteriology, structure and composition of black stains on human permanent teeth in Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B38627966.
Testo completo
42
McInnes, James Christopher. "Low-frequency acoustic energy, cavitation, and their effects on bacteria /". Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/8041.
Testo completo
43
Deacon, Paul Robert. "The preparation, characterisation and anti-bacterial activity of orally-viable tin(II) salts". Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240664.
Testo completo
44
Lif, Holgerson Pernilla. "Xylitol and its effect on oral ecology : clinical studies in children and adolescents". Doctoral thesis, Umeå : Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-986.
Testo completo
45
Aires, Carolina Patricia. "Efeito in vitro e in situ do amido e sua combinação com sacarose na composição do biofilme e na desmineralização in situ da dentina radicular". [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289310.
Testo completoAbstract (sommario):
Orientadores: Jaime Aparecido Cury, Hyun KooTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-10T06:35:17Z (GMT). No. of bitstreams: 1 Aires_CarolinaPatricia_D.pdf: 3028727 bytes, checksum: 2801d7baaa2bd663ff7b8748629b5d05 (MD5) Previous issue date: 2008
Resumo: Sacarose é o mais cariogênico dos carboidratos da dieta e há evidências que sua cariogenicidade aumenta quando associada ao amido. Isso seria explicado pelas mudanças na matriz do biofilme formado, pois de acordo com estudo in vitro um ¿novo¿ polissacarídeo extracelular (EPS) é sintetizado pela glicosiltransferase (GTF) B de S. mutans a partir de sacarose e hidrolisados do amido. Entretanto, isso precisa ser confirmado em biofilmes, pois o efeito desse ¿novo¿ polissacarídeo pode não ser evidenciado quando da ação simultânea das diferentes GTFs de S. mutans e de outras bactérias. Em acréscimo, a maior cariogenicidade da associação amido-sacarose é conhecida para o esmalte, mas não para dentina. Na realidade, não há evidência nem mesmo se amido isoladamente seria cariogênico para dentina e cárie radicular é uma preocupação atual considerando o declínio de cárie, maior retenção de dentes e o aumento da expectativa de vida das populações. Assim, o objetivo da presente tese foi estudar a influência da associação amido-sacarose em biofilmes in vitro e in situ. In vitro, biofilmes de S. mutans foram formados sobre discos de hidroxiapatita na presença de amido, sacarose ou associações. In situ, a cariogenicidade da associação amido-sacarose foi testada através de um estudo cruzado e em cada fase blocos de dentina radicular foram submetidos extraoralmente a tratamentos com soluções de amido, sacarose ou suas combinações. Os biofilmes formados in vitro e in situ foram analisados quanto às suas composições bioquímicas e microbiológicas, enquanto que cárie dentinária foi avaliada somente in situ. O biofilme de S. mutans formado in vitro na presença da associação amido-sacarose mostrou composição distinta em EPS em relação àquele formado na presença dos açúcares isolados, porém o mesmo não foi evidenciado in situ. Quanto à expressão dos genes gtfBCD, resultados preliminares promissores foram encontrados mas aparentemente distintos para as condições in vitro e in situ. Amido se mostrou levemente cariogênico para dentina em comparação com sacarose, mas a associação amido-sacarose não foi mais cariogênica que sacarose isolada. Conclui-se que embora haja evidências que a associação amido-sacarose possa aumentar a cariogenicidade do biofilme formado, isso não foi confirmado in situ para dentina radicular, pois a associação não se mostrou mais cariogênica que sacarose isolada
Abstract: Sucrose is the most cariogenic of the dietary carbohydrates but there is evidence that its cariogenicity is enhanced when used in combination with starch. This could be explained by changes in biofilm matrix, since an in vitro study showed that a novel extracellular polysaccharide (EPS) is synthesized by glicosiltransferase (GTF) B of S. mutans in presence of sucrose and starch hydrolysates. However, this should be confirmed in biofilms since the effect of this novel polysaccharide could not be evidenced when different GTFs from S. mutans and from other bacteria are synthesized simultaneously. In addition, the cariogenicity of starch-sucrose combination is well established for enamel but not for dentine. Also, evidence is still lacking on the cariogenicity of starch for root dentine, and root caries is a current concern considering the decline of caries, higher tooth retention and the increase of the life expectancy for populations. Thus, the aim of this study was to evaluate the influence of starch, sucrose and their combinations in in vitro and in situ biofilms. In vitro, S. mutans biofilms were formed on hydroxyapatite discs in presence of starch, sucrose or their combination. In situ, the cariogenicity of starch-sucrose association was tested by a crossover study and during each phase root dentine slabs were submitted extraorally to solutions of starch, sucrose or starch-sucrose association. In vitro and in situ biofilms were analyzed for biochemical and microbiological composition, and root dentine caries was evaluated in situ. In vitro biofilms formed in presence of starch-sucrose association showed distinct EPS composition in relation to those formed in the presence of isolated sugars, but the same trend was not evidenced in situ. In relation to gtfBCD expression, promising preliminary results were found, but they were distinct for in vitro and in situ studies. Starch was moderately cariogenic for dentine in comparison to sucrose but starch-sucrose association was not more cariogenic than sucrose alone. In conclusion, although starch-sucrose association could enhance the cariogenicity of the biofilm formed, this trend was not confirmed in situ for root dentine since the association was not more cariogenic than sucrose alone
Doutorado
Cariologia
Doutor em Odontologia
46
Oliveira, Francisco Artur Forte. "Molecular analysis of oral bacteria in dental plaque, saliva and cardiac valve of patients with cardiovascular disease". Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9733.
Testo completoAbstract (sommario):
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoCoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Over the past few years, there has been increasing evidence of the effect of the oral health over the general health of individuals, supported by a series of biological and epidemiological studies that show a relation between the mouth and many diseases, including cardiovascular diseases. Structural deficiencies and functional abnormalities of heart valves represent an important cause of cardiovascular morbidity and mortality in Brazil, and a few defects have been recently associated with infectious agents. The aim of this study was to identify cariogenic and periodontopathogenic bacteria in dental plaque, saliva and heart valves, without clinical endocarditis, of patients with heart valve diseases, and correlate these findings with the oral health status of the patients. Oral exams using the DMTF (decayed, missing and filled teeth) and PSR (Periodontal Screening and Recording) indexes to evaluate caries and periodontal disease, respectively, were performed. Samples of supragingival and subgingival dental plaque, saliva and cardiac valves were evaluated, through Real Time Polymerase Chain Reaction, for the presence of DNA of Streptococcus mutans (S. mutans), Prevotella intermedia (P. intermedia), Porphyromonas gingivalis (P. gingivalis) and Treponema denticola (T. denticola). A total of 114 samples were collected from 42 patients with a mean age of 55.6 Â 13.8 years. The average number of missing teeth due to caries was 23.52 Â 9.41 teeth per patient, and according to the highest score of periodontal disease observed for each patient, excluding edentulous patients (44.0%), periodontal pockets over 4mm (43.4%) and dental calculus (34.7%) were detected in a higher number of patients. The molecular analysis of the oral samples revealed high frequency of S. mutans and P. intermedia in supragingival dental plaques, subgingival dental plaques and saliva of dentate and edentulous patients (variation 60.0% - 100.0%), while P. gingivalis and T. denticola were detected in a smaller number of oral samples (variation 17.6% - 64.0%). The microorganism most frequently detected in heart valve samples was the S. mutans (89.3%), followed by P. intermedia (19.1%), P. gingivalis (4.2%) e T. denticola (2.1%). Significant difference was observed between the frequency of P. intermedia, P. gingivalis and T. denticola in the heart valve and dental plaque, as oposed to S. mutans. The identification of oral bacteria, especially S. mutans, in heart valves of patients with a previous history of dental caries and gingivitis/periodontitis suggests the possible involvement of these pathogens in the etiopathogenesis of heart valve diseases.
Atualmente, cada vez mais se tem evidÃncias do efeito da condiÃÃo oral na saÃde geral dos indivÃduos, atravÃs de uma sÃrie de estudos epidemiolÃgicos e biolÃgicos que mostram uma relaÃÃo entre a boca e diversas doenÃas, incluindo as doenÃas cardiovasculares. Desordens estruturais e nas funÃÃes das vÃlvulas cardÃacas representam uma importante causa de morbidade e mortalidade cardiovascular no Brasil, sendo alguns processos, como a estenose aÃrtica degenerativa, mais recentemente associados a agentes infecciosos. O objetivo desta pesquisa foi identificar bactÃrias cariogÃnicas e periodontopatogÃnicas na placa dental, saliva e vÃlvulas cardÃacas, sem endocardite clÃnica, de pacientes com doenÃa valvar, correlacionando esses achados à condiÃÃo bucal dos indivÃduos. AvaliaÃÃo, quanto Ãs doenÃas cÃrie e periodontal, foi realizada, atravÃs dos Ãndices CPO-D (Dentes Permanentes Cariados, Perdidos e Obturados) e PSR (Registro Periodontal Simplificado), respectivamente. Amostras de placa dental supragengival, subgengival, saliva e vÃlvula cardÃaca foram coletadas para investigaÃÃo da presenÃa de DNA, atravÃs de PCR (ReaÃÃo em Cadeia de Polimerase) em tempo real, de Streptococcus mutans (S. mutans), Prevotella intermedia (P. intermedia), Porphyromonas gingivalis (P. gingivalis) e Treponema denticola (T. denticola). Um total de 114 amostras foi coletado de 42 pacientes com mÃdia de idade de 55.6  13.8 anos. A mÃdia de dentes perdidos devido à cÃrie, por paciente, foi em torno de 23.52  9.41 e, segundo o maior grau de doenÃa periodontal observado no indivÃduo, excluindo-se os pacientes desdentados totais (44.0%), bolsa superior a 4 mm (43.4%) e o cÃlculo dental (34.7%) esteve presente em um maior nÃmero de pacientes. A anÃlise molecular das amostras bucais revelou alta frequÃncia de S. mutans e P. intermedia nas placas supragengival, subgengival e saliva de pacientes dentados e desdentados (variando entre 60.0% e 100.0%), enquanto que P. gingivalis e T. denticola estiveram presentes em menor nÃmero de amostras bucais (variando entre 17.6% e 64.0%). O micro-organismo mais frequentemente encontrado nas amostras valvares foi o S. mutans (89.3%), seguido da P. intermedia (19.1%), P. gingivalis (4.2%) e T. denticola (2.1%). DiferenÃa significativa foi encontrada entre a presenÃa de P. intermedia, P. gingivalis e T. denticola na vÃlvula e na placa dental, diferentemente do S. mutans. A identificaÃÃo de bactÃrias orais, principalmente S. mutans, em vÃlvulas cardÃacas de pacientes com elevada experiÃncia prÃvia de cÃrie e ocorrÃncia de gengivite/periodontite, sugere o possÃvel envolvimento desses patÃgenos nas doenÃas valvares.
47
Kum, John Minwoo. "QUANTITATIVE ANALYSIS OF AGGREGATIBACTER ACTINOMYCETEMCOMITANS IN DENTAL PLAQUE SAMPLES OF MOROCCAN SCHOOL CHILDREN WITH AND WITHOUT PERIODONTITIS". Master's thesis, Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/552380.
Testo completoAbstract (sommario):
Oral BiologyM.S.
Objectives: Microbial infection and the host response to the infection play a significant role in the etiology of periodontal diseases. Previous studies reported a relatively high prevalence of periodontitis among adolescents in Morocco. The importance of the composition of subgingival plaque and the presence and proportion of Aggregatibacter actinomycetemcomitans to the total plaque bacteria in the pathogenesis of periodontitis is not well understood. The purpose of this study is to compare the relative abundance of A. actinomycetemcomitans in subgingival dental plaque from young Moroccans with aggressive periodontitis, chronic periodontitis, and those without periodontitis, and to construct a multivariable model to investigate the effect of demographic attributes of age, gender and relative ratio of A. actinomycetemcomitans in dental plaque with periodontal disease status. Methods: Sample population includes 984 subjects, aging from 12-20 years old, who were surveyed and examined for periodontal disease status. 82 subjects were selected consisting of 26% aggressive periodontitis, 12% chronic periodontitis, and 62% without periodontitis. Subgingival plaque was collected from these 82 subjects. Whole DNA was extracted and purified, and real-time PCR was used employing a primer for eubacteria, and specific primer for A. actinomycetemcomitans. PCR assays confirmed the amplification and quantification of DNA of total bacterial and A. actinomycetemcomitans. Results: 73% of the subjects harbored A. actinomycetemcomitans: 63% in aggressive periodontitis, 90% in chronic periodontitis, and 73% in controls. The percentage A. actinomycetemcomitans to total bacterial load increased with age, was similar among males and females, and was somewhat higher in persons with periodontitis than the controls. Using a logistic regression analysis that included age, gender and A. actinomycetemcomitans ratio showed that only age is significantly correlated with the diagnosis of periodontitis in this population. Conclusions: A. actinomycetemcomitans is prevalent among this young Moroccan group and is somewhat more prevalent in subjects with periodontitis than the controls. However, the presence and ratio of this species to the total bacteria in subgingival plaque explained only a small proportion of the variance in periodontitis in this group.
Temple University--Theses
48
Oliveby, Anette. "Studies on the kinetics of fluoride in human saliva and its effects on plaque acidogenicity". Stockholm : Kongl. Carolinska Medico Chirurgiska Institutet, 1991. http://catalog.hathitrust.org/api/volumes/oclc/24041830.html.
Testo completo
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Matthews, Chad Robert. "Host Bacterial Interactions During Early Plaque Formation in Current and Never Smokers". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274112198.
Testo completo
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Arthur, Rodrigo Alex. "Avaliação de caracteristicas fenotipicas de cariogenicidade de genotipos de Strptococcus Mutans isolados de biofilme dental". [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/290570.
Testo completoAbstract (sommario):
Orientadores: Cinthia Pereira Machado Tabchoury, Renata de Oliveira Mattos-GranerTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Os estreptococos do grupo mutans, em especial Streptococcus mutans, são considerados como um dos principais microrganismos relacionados à doença cárie dental. Clinicamente, esses microrganismos estão presentes na cavidade bucal na forma de diferentes genótipos, que podem apresentar diferentes características fenotípicas. Nesse sentido, foi avaliada diversidade genotípica de S. mutans em biofilme dental formado in vivo ou in situ durante 3 dias sob condições controladas de exposição à sacarose, o mais cariogênico dos carboidratos, e os seus monossacarídeos constituintes (glicose e frutose). Diferentes genótipos de S. mutans foram encontrados nessas distintas condições, entretanto, não foi observada seleção de genótipos nos biofilmes dentais formados. Além disso, as características fenotípicas de virulência desses genótipos não foram avaliadas. Sendo assim, seria importante avaliar nesses genótipos previamente isolados de biofilme dental formado in vivo e in situ, na presença ou ausência de sacarose, as características fenotípicas de cariogenicidade relacionadas à aciduricidade e à acidogenicidade, visando investigar a relação entre um alto desafio cariogênico (exposição frequente à sacarose e acúmulo de biofilme) e a virulência de S. mutans. Tanto naqueles genótipos previamente isolados de biofilme dental formado in vivo, quanto naqueles isolados de biofilme dental formado in situ, a aciduricidade foi avaliada em relação à análise da viabilidade celular em condições ácidas e em relação à atividade da bomba F-ATPase, e a acidogenicidade foi avaliada em relação à análise da curva de queda de pH devido metabolização de glicose. Além disso, oito genótipos previamente isolados do biofilme dental formado in situ durante 3 dias foram submetidos a um crescimento na forma de biofilme in vitro, condição na qual foram avaliadas a acidogenicidade, a habilidade do genótipos em sintetizar polissacarídeos extracelulares e o potencial desses genótipos para desmineralizar o esmalte dental. Em relação aos genótipos isolados de biofilme dental formado in vivo, aqueles isolados de biofilme formado na presença de sacarose foram mais ácido-tolerantes, tanto em pH 5,0 ou 2,8, e mais acidogênicos, uma vez que apresentaram menores valores de pH final durante a análise da curva de queda de pH e também maior velocidade na produção de ácidos nos primeiros 15 minutos de metabolização da glicose, que aqueles encontrados em biofilme formado na sua ausência de sacarose. Além disso, não foram encontradas diferenças expressivas na atividade da bomba F-ATPase entre essas duas condições distintas. Comportamento semelhante também foi observado para genótipos previamente isolados de biofilme dental formado in situ, com maior aciduricidade e acidogenicidade para aqueles genótipos isolados de biofilme formado na presença de sacarose. No modelo de biofilme in vitro não foram encontradas diferenças nem na acidogenicidade nem na habilidade dos genótipos de produzirem polissacarídeos extracelulares. Entretanto, os genótipos apresentaram potenciais cariogênicos distintos, não havendo relação entre o potencial cariogênico desses genótipos e a condição na qual esses genótipos foram isolados (presença ou ausência de um alto desafio cariogênico). Os resultados sugerem que as freqüentes quedas de pH decorrentes da exposição à sacarose parecem tornar os genótipos mais de S. mutans mais virulentos. Além disso, genótipos distintos de S. mutans podem apresentar diferentes potenciais cariogênicos.
Abstract: Mutans streptococci, mainly Streptococcus mutans, are considered as the main microorganisms related to dental caries. These microorganisms are present in oral cavity as distinct genotypes, which may show distinct phenotypic traits. In this context, it was evaluated the S. mutans genotypic diversity in dental biofilm formed in vivo and in situ during 3 days under controlled exposure to sucrose, the most carigenic carbohydrate, and its monosaccharides constituents (glucose and fructose). Distinct S. mutans genotypes were found under these before mentioned conditions, but no selection of them was found in dental biofilms formed. Moreover, the virulence phenotypic traits of these genotypes were not evaluated. Thus, it would be important to evaluate in these genotypes previously isolated from dental biofilm formed in vivo and in situ in the presence or absence of sucrose, the phenotypic traits of cariogenicity related to aciduricity and acidogenicity in order to investigate the relationship between a high cariogenic challenge (frequent exposure to sucrose and biofilm accumulation) and their virulence. Either in those genotypes isolated from in vivo dental biofilms, or in those isolated from in situ dental biofilms, the acidogenicity trait was evaluated through counts of viable cells in acid conditions and F-ATPase activity, and the acidogenicity trait was evaluated through the ability to lower the pH due to glycolysis. Besides, eight genotypes previously isolated from in situ dental biofilms formed during three days were grown as in vitro biofilms, and these genotypes were evaluated regarding their acidogenicity, cariogenic potential and ability to synthesize extracellular polysaccharides. In relation to genotypes isolated from in vivo biofilms, those isolated from biofilms formed in the presence of sucrose were more acid-tolerant, either at pH 5.0 or at pH 2.8, and more acidogenic, since they showed lower values of final pH during the evaluation of the curve of pH fall and also higher ability to produce acids in the first 15 minutes of glucose fermentation, than genotypes isolated from in vivo biofilms formed in the absence of sucrose. Besides, no expressive differences regarding F-ATPase activity between these two distinct conditions were found. Genotypes found only in the presence of sucrose were more acidogenic than those found only in the absence of this carbohydrate. Similar data were found for genotypes isolated from in situ dental biofilms formed in the presence of sucrose, which were more aciduric and more acidogenic than genotypes isolated from biofilms formed in the absence of this carbohydrate. In in vitro biofilm model, no differences either in the acidogenicity or in the ability of genotypes to synthesize extracellular polyssacharide were found. However, the S. mutans genotypes showed distinct cariogenic potential, independent of the fact that these genotypes had been isolated in the presence or absence of a high cariogenic challenge. The results suggest that frequent pH fall due to sucrose exposure may select more virulent S. mutans genotypes. Besides, distinct S. mutans genotypes may show distinct cariogenic potential.
Doutorado
Cariologia
Doutor em Odontologia