Dissertations / Theses on the topic 'Adhesive dentistry'

2012/2013
The subject of this thesis is the stability of the adhesive interface in dentistry. Success in adhesive dentistry means long lasting restorations. However, there is substantial evidence that this ideal objective is not achieved. Current research in this field aims at increasing the resin-dentin bond durability. This doctoral research examines the fundamental processes responsible for the aging mechanisms involved in the degradation of resin-bonded interfaces, as well as some potential approaches to prevent and counteract this degradation. Resin-dentin bond degradation is a complex process that is not completely understood, involving the hydrolysis of both the resin and the collagen component of the hybrid layer. The hydrophilic and acidic characteristics of current dentin adhesives have made hybrid layers highly prone to water sorption, which causes polymer degradation and results in decreased resin-dentin bond strength over time. These unstable polymers inside the hybrid layer may result in an incomplete encapsulation of collagen fibers, which become vulnerable to mechanical and hydrolytical fatigue, as well as degradation by host-derived proteases with collagenolytic activity. These enzymes, such as matrix metalloproteinases (MMPs) and cysteine cathepsins, have a crucial role in the degradation of type I collagen, the organic component of the hybrid layer. The first part of this thesis aims to review the current knowledge regarding adhesion to the tooth substrate (Chapter 1), focusing on the fundamental processes that are responsible for the degradation of the adhesive interface (Chapter 2). Since the permeability of adhesives to water is particularly evident in simplified adhesive formulations, the research activity was focused on self-etch and universal adhesive systems’ behavior. Thus, the research study reported in Chapter 3 showed that the bond strength and nanoleakage expression of two-step and one-step self-etch tested bonding systems were affected by storage for 6 month and 1 year in artificial saliva. Although it is generally accepted that the permeability of adhesives to water is particularly evident in simplified adhesive formulations, the stability over time was not related to the number of steps of bonding systems, but to their chemical formulations. The performance of a new universal (or multi-mode) adhesive system through storage in artificial saliva was also investigated. The original results presented in Chapter 4 found that improved bonding effectiveness of the tested universal adhesive system on dentin was obtained when the adhesive was applied with the self-etch approach. Indeed, the etch-and-rinse approaches tested (both on wet and dry dentin) resulted in immediate bond strength comparable to the self-etch mode but expedited long-term aging resulted in reduced bond strength and increased nanoleakage expression, irrespective of dentin wetness. Moreover, the results of the zymographic analysis showed evident changes in dentinal MMP-2 and -9 enzyme activities after the application of the tested adhesives, revealing differences in the extent of enzyme activation. These findings exhibit that the activation of endogenous MMPs is not related to the adhesive system or the strategy employed. Thus, regardless of the approach and the material used in bonding procedures, a stable and durable bond is not achieved. Therefore, experimental strategies that aim to enhance the adhesive interface, particularly improving the durability of the resin-dentin bond strength by inhibiting intrinsic collagenolytic activity and increasing the resistance of dentin collagen matrix to enzymatic degradation are needed. The last part of the thesis is focused on both the strategies to inhibit the proteolytic and collagenolytic activity of the endogenous proteases and the methods to increase the mechanical strength of collagen network and its resistance to enzymatic degradation (Chapter 5). Chlorhexidine (CHX) has been used as a non-specific MMP inhibitor to prevent degradation of hybrid layers. However, CHX is water-soluble and may leach out of hybrid layers, compromising its long-term anti-MMP effectiveness. An entirely different approach is to treat the acid-etched dentin containing activated matrix-bound MMPs with cross-linking agents that inactivate the catalytic site of proteases. In particular, the ability of a cross-linker agent, 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide (EDC), to prevent collagen degradation was evaluated under occlusal cycle loading. Previous research successfully utilized EDC to increase the durability of resin-dentin bonds by increasing the mechanical properties of the collagen matrix; however, the 1 to 4 hrs required for that procedure was clinically unacceptable. For this reason, the purpose of the last part of the research, presented in Chapter 6, was to evaluate the ability of 0.5 M EDC short-time (1 min) pre-treatment to improve the stability of demineralized dentin collagen matrices by quantifying the release of telopeptide fragments over time. The results showed that EDC application for 1 min may be a clinically relevant and effective means for stabilizing the collagen network not only by strengthening the fibrils, but also by reducing the enzymatic degradation rate. Thus, dentin collagen reinforcement and strengthening through EDC cross-linking might be of importance to improve the bond strength and structural integrity of the resin-dentin interface over time against the enzymatic and hydrolytic degradation.
La tesi qui presentata riguarda la stabilità dell'interfaccia adesiva in odontoiatria. Il successo delle moderne terapie conservative è rappresentato dalla longevità dei restauri adesivi. Tuttavia, vi è una sostanziale evidenza che questo obiettivo ideale non sia raggiunto. La stabilità dell’interfaccia adesiva dipende dalla formazione di uno strato ibrido, compatto e omogeneo, durante l’impregnazione del substrato dentinale da parte dei monomeri adesivi. Poiché lo strato ibrido rappresenta un’entità complessa, in cui interagiscono componenti biologiche diverse (matrice dentinale collagenica e cristalli d’idrossiapatite residui) e non (monomeri resinosi e solventi), i fenomeni d’invecchiamento interessano in maniera sinergica sia la porzione resinosa che quella dentale. L’articolato processo che porta alla degradazione dell’interfaccia adesiva coinvolge infatti la componente resinosa, attraverso l’idrolisi della resina negli spazi interfibrillari, e quella organica, attraverso la disorganizzazione delle fibre collagene dovuta ad un incompleto incapsulamento delle stesse, nonché alla degradazione da parte di proteasi intrinseche con attività collagenolitica. È stato dimostrato come questi enzimi, le metalloproteinasi della matrice (MMP) e le catepsine, abbiano un ruolo cruciale nella degradazione del collagene di tipo I, la principale componente organica dello strato ibrido. Inoltre le caratteristiche idrofile e acide degli attuali sistemi adesivi dentinali hanno reso lo strato ibrido molto suscettibile all'assorbimento di acqua, comportando, attraverso l’idrolisi, la degradazione dello stesso e andando così a contribuire ad una diminuzione della forza di legame nel tempo. Attualmente l’interesse della comunità scientifica mira ad aumentare la durata del legame adesivo con il substrato dentinale. Dopo un’attenta analisi delle attuali conoscenze riguardanti adesione al substrato dentale (Capitolo 1), la prima parte della tesi si propone di valutare i processi fondamentali che sono responsabili della degradazione dell'interfaccia adesiva (Capitolo 2). Poiché la permeabilità all’acqua degli adesivi è particolarmente evidente nelle formulazioni semplificate, l'attività di ricerca si è concentrata sull’analisi del comportamento dei sistemi adesivi self-etch e dei recenti sistemi adesivi universali. I risultati riportati nel Capitolo 3 ha dimostrato come la forza di legame e l’espressione del nanoleakage dei sistemi adesivi self-etch two-step e one-step testati sia negativamente influenzata dall’invecchiamento in saliva artificiale per 6 mesi e 1 anno. Sebbene sia generalmente accettato che la permeabilità degli adesivi all'acqua è particolarmente evidente in formulazioni di adesivi semplificati, la stabilità nel tempo non è stata correlata al numero di passaggi dei sistemi adesivi, bensì alle loro composizioni chimiche. Sono state in seguito analizzate anche le prestazioni di un nuovo sistema adesivo universale (o multimodale). I risultati presentati nel Capitolo 4 hanno stabilito una migliore efficienza adesiva del sistema universale, testato sul substrato dentinale, quando l'adesivo è stato applicato con l'approccio self-etch. Infatti, la tecnica etch-and-rinse, testata sia su dentina umida che secca, ha comportato una forza di adesione immediata paragonabile alla modalità self-etch, ma a tempi di invecchiamento incrementali si è evidenziata una diminuzione della forza di legame e una maggiore espressione del nanoleakage, a prescindere dalla condizione di umidità dentinale. Inoltre, i risultati dell'analisi zimografica hanno mostrato evidenti variazioni dell’attività enzimatica delle metalloproteinasi MMP-2 e -9 dopo l'applicazione degli adesivi testati. Questi risultati dimostrano come l'attivazione delle MMP endogene non sia correlata al sistema adesivo o alla strategia adottata. Ne evince che, indipendentemente dal metodo e dal materiale utilizzato nelle procedure adesive, non si è in grado di stabilire un legame affidabile e duraturo. Pertanto si avverte l’esigenza di strategie sperimentali che mirino a migliorare la stabilità dell’interfaccia adesiva, in particolare incrementando la durata della forza di legame in dentina inibendo l'attività collagenolitica intrinseca e aumentando la resistenza del collagene alla degradazione enzimatica. L'ultima parte della tesi è focalizzata quindi sulle strategie per inibire l'attività proteolitica e collagenolitica delle proteasi endogene e sui metodi per aumentare la resistenza meccanica del collagene alla degradazione enzimatica (Capitolo 5). Un potente agente antibatterico, la clorexidina (CHX), è stato usato come inibitore non specifico delle MMP al fine di impedire la degradazione dello strato ibrido. Tuttavia la CHX, essendo solubile in acqua, può dissolversi nello strato ibrido, compromettendo la sua efficacia anti-MMP a lungo termine. Un approccio completamente diverso è quello di trattare la dentina mordenzata con agenti cross-linker. In particolare, simulando il carico occlusale, è stata valutata la capacità di un agente cross-linker, l’1-etil-3-(3-dimetilammino-propil) carbodiimmide (EDC), per prevenire la degradazione del collagene. Precedenti ricerche hanno utilizzato con successo l’EDC con lo scopo di aumentare la durata dell’interfaccia adesiva, aumentando le proprietà meccaniche della matrice di collagene; tuttavia, il tempo necessario (da 1 a 4 ore) richiesto per tali procedure è clinicamente inaccettabile. Per questo motivo, lo scopo dell’ultima parte della ricerca, presentata nel Capitolo 6, è stato quello di valutare la capacità di 0,5 M EDC nel breve periodo di pretrattamento (1 min), andando a quantificare il rilascio di frammenti di telopeptidi di collagene nel corso del tempo. I risultati hanno dimostrato che l'applicazione di EDC per 1 min può essere un approccio clinicamente rilevante ed efficace nello stabilizzare il collagene, non solo rafforzando le fibrille, ma anche riducendo la velocità di degradazione enzimatica. Di conseguenza, l’utilizzo di questo cross-linker può garantire una valida strategia per migliorare la forza di legame e l'integrità strutturale dell'interfaccia adesiva nel tempo contro l’attività enzimatica intrinseca del collagene e la degradazione idrolitica.
XXVI Ciclo
1985

Objective: To assess the effects of ceramic opacity and thickness on delivered radiant exposure and degree of conversion and microhardness of the light-cured resin cement. Materials and Methods: IPS e-Max ceramic discs (Ivoclar Vivadent) were fabricated in 3 thicknesses (0.5, 1.0, and 1.5mm) and 4 opacities (HT, LT, MO, HO) (n=3/per group). Light-cured resin cement (Variolink Veneer Luting Cement - shade MVO, Ivoclar Vivadent) 50µm thick was cured through these ceramics disks using a quartz tungsten halogen curing light unit (Optilux 501, Kerr) with its radiant exposure measured by MARC from a fixed distance (1.5mm). Knoop microhardness was used to evaluate the bottom degree of cure and was correlated with the radiant exposure deliverd. Descriptive statistics were conducted. One- and two-way ANOVA with post-hoc Tukey's HSD test, Pearson correlation test, the simple linear regression analysis were used for the statistical analyses (alpha=0.05). Results: Significant interaction was found between ceramic thickness and opacity on radiant exposure (p=0.0078). Subsequent analyses demonstrated that there was a significant simple effect for opacity and for thickness on radiant exposure under different conditions of thickness and opacity. A significant relationship was found between resin cement microhardness and radiant exposure (p=0.0001) below 4.5 J/cm2. Moreover, the Pearson correlation coefficient of 0.93 indicated a strong correlation between the two variables below 4.5 J/cm2 of radiant exposure delivered. Conclusion: Ceramic opacity and thickness affect the polymerization of light-cured resin cements and need to be considered and compensated for when bonding indirect restorations. Based upon the findings of this preliminary study, the final study is ongoing.

Purpose: This study evaluated microleakage associated with cast restorations that were luted with a resin-modified glass ionomer cement (RelyX) following obturation of the dentinal tubules with either a desensitizing agent (Gluma Desensitizer) or an adhesive system (Scotchbond Multipurpose Dental Adhesive). The effect of acid etching on the removal of the smear layer and its influence on the extent of microleakage associated with the adhesive system was also evaluated. Materials and Methods: Extracted mandibular premolars (N = 48) were prepared for complete cast restorations and divided into 4 groups (N = 12). In group A ( control), neither a desensitizing agent or a component of the adhesive system was applied prior to luting. In group B, Gluma Desensitizer was used to obturate the dentinal tubules. In group C, Scotchbond Multipurpose Dental Adhesive System was applied to tooth preparations according to the manufacturer's instructions. Tooth preparations in group D received the same dentin surface treatment as in group C, but no acid etching was performed. Cast restorations in all 4 groups were then luted with the resin-modified glass ionomer luting cement RelyX. All specimens were subjected to thermocycling between 8° and 55°C for 500 cycles in water baths, placed in a solution of 0.5% basic fuchsin dye for 24 hours, and then sectioned twice longitudinally, once mesiodistally and then buccolingually. All specimens were examined at X30 magnification with a stereomicroscope equipped with a digital camera. Photographs of all sections were made and the extent of microleakage along the tooth-cement interface was measured in millimeters using an image analysis software. Microleakage was perceived to have occurred along a segment of the tooth-luting cement interface when dye penetration from that segment into the dentinal tubules was detected. One-way analysis of variance (α = 0.05) was performed to identify differences in mean microleakage among the luting groups, followed by Tukey's Honestly Significant Difference Test for pairwise comparisons. Results: Large standard deviations were found in all 4 groups. No statistically significant difference was found among the control (0.64 ± 0.50 mm), Gluma Desensitizer (0.42 ± 0.24 mm), and Scotchbond Multipurpose without etching (0.67 ± 0.40 mm) groups. However, a statistically significant difference was found between the Scotchbond Multipurpose with etching (1.51 ± 0.92 mm) group and each of the other groups. Conclusions: The large standard deviations obtained implied a marked amount of variability in microleakage within each group, which might be the result of the small sample size used. The increase in microleakage when 35% phosphoric acid was used prior to dentin bonding is difficult to explain. Within the limitations of the study, the results suggest that the use of a nonpolymerizing, resin-based (Gluma Desensitizer) material or a photopolymerizing, resin-based (Scotchbond Multipurpose) system without etching had no effect on microleakage under cast restorations luted with the resin-modified glass ionomer luting cement RelyX. The increase in microleakage when etching with 35% phosphoric acid was preformed might be explained by the phenomenon known as nanoleakage, but further investigation is recommended in this area.

Oral Biology
M.S.
Objectives: While bracket debonding has been explored through shear bond-strength tests with debonding linked to the type of material used, the technique of adhesive application, and contamination, the contribution of internal voids in orthodontic adhesives is unknown. Voids may result in fracture or bond-failure, either within the adhesive or at the tooth-adhesive-bracket interfaces. The aim of this thesis is to quantify the internal volumetric voids and bonding strength of three generations of bracket adhesives. Methods: Extracted third molars were bonded with three groups of orthodontic brackets including conventionally-pasted (CP), pre-coated (PC), or pre-coated flash-free (FF) (n=5 per group). The three-dimensional internal structure of the adhesive was evaluated with Micro Computed Tomography (micro-CT) using the Skyscan micro-CT (maximum resolution of 5 microns). Data from the micro-CT were analyzed with SkyScan software to perform 3D reconstructions, image processing, and qualitative and quantitative analysis of the adhesive’s structure. The amount of void was determined by measuring the percentage of voids at the bonded interfaces (Vint) and within the adhesive (Vbulk). The total amount of void was also calculated (Vtot= Vint+ Vbulk). Differences in void between the groups were assessed using one-way ANOVA with post-hoc Tukey tests (α=0.05). The bonding strength of the three adhesives systems was evaluated via shear bond strength tests. Results: Our void quantification results showed that FF brackets had a statistically higher (p0.05) for any the analyzed locations (Vint, Vbulk). Our results indicate the majority of voids were found at bonded interfaces (Vint) compared to within the bulk (Vbulk) for all three groups, with statistically significant (p<0.05) differences for CP and FF. Our bonding strength evaluation revealed the pre-coated group (PC) to have on average the highest bond strength compared to conventionally-pasted (CP) and pre-coated flash-free (FF) groups. Conclusions: The overall amount of void in the pre-coated flash-free adhesive brackets is significantly higher compared to conventionally-pasted and pre-coated groups. The majority of the void was identified to be located at the bonded interfaces (tooth/adhesive and bracket/adhesive) rather than within the bulk of the adhesive for all groups. Our bonding strength results indicate the pre-coated brackets to have the highest bond strength compared to pre-coated flash-free and conventionally-pasted. Our preliminary set of results indicate an inverse relationship between bonding strength and amount of void of brackets adhesives, with the pre-coated exhibiting the highest bond strength and least void. However, due to a limited sample size additional data are needed to validate these conclusions and find solid relationships between adhesive voids and bonding strength.
Temple University--Theses

The objective of this work was to develop a short-term, clinically simulative, biofilm-based aging/storage model for lab testing of newer dental adhesives in order to predict their long-term performance. To do this we tested the hypothesis that 15 days of biofilm challenge with cariogenic bacterial species, Streptococcus mutans (SM) and Streptococcus sobrinus (SS), would produce similar or a greater reduction in microtensile bond strength (μTBS) of dental adhesives as compared to a standard 6 months of water storage (WS). Thirty-one molars were flattened to dentin, restored using Optibond-FL adhesive and Z-100 dental composite, sectioned and trimmed into four dumbbell-shaped specimens and randomly distributed according to aging conditions (n=31): A) Water storage for 6 months, B) Water storage for 5.5 months + S. mutans-biofilm challenge for 15 days, C) S. mutans-biofilm challenge for 15 days and D) S. sobrinus-biofilm challenge for 15 days. Specimens were gripped centrally with respect to the test axis with a non-gluing passive gripping device. Microtensile bond strength testing was performed using a Zwick Material Testing Machine at a crosshead speed of 1 mm/min and failure modes were classified using light microscopy. Mixed model ANOVA and Weibull regression analysis revealed that the type of storage condition significantly affected the microtensile bond strength (p<0.0001). Mean microtensile bond strength observed within group A (49.69 ± 15.53MPa) was significantly higher than those in groups B (19.26 ± 6.26MPa), C (19.92 ± 5.86MPa) and D (23.58 ± 7.88MPa). Also, microtensile bond strength obtained with group D was significantly greater than that with groups B and C, while no difference was seen between the latter two groups. Chi-square statistical analysis indicated that specimens from groups B (74.2%), C (83.9%) and D (80.6%) were more likely to have cohesive failures in dentin than specimens from group A (54.8%). Within the limitations of the study, it can be concluded that 15 days of Streptococcus mutans- and Streptococcus sobrinus- based biofilm challenge produced more reduction in microtensile bond strength of dental adhesive than 6 months of water storage and appear to be a promising in vitro accelerated aging model.

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.

Syfte: Syftet med föreliggande in-vitro studie är att undersöka olika kompositbaserade reparationssystem och dess bindningsstyrka till porslin för metallkeramiska konstruktioner. Material och metod: Metallstavar tillverkades via CAD/CAM i CoCr (5.0x5.0x15.0mm) kortsidan förbehandlades genom sandblästring (aluminumoxid, 250 µm), ångblästring, oxidation, sandblästring och ångblästring. Fältspatporslin applicerades enligt följande: opak, dentin, emalj, till höjden av 1.2 ± 0.2 mm. Porslinsytorna slipades med sandpapper, 600-, 800-, 1200-kornstorlek kiselkarbid. Fem grupper (n=15) gav totalt 75 provkroppar. På vardera provkropp applicerades adhesiv samt kompositmaterial enligt fabrikanternas anvisningar (Kuraray, Kulzer, Voco, Ivoclar) inklusive kontrollgrupp som etsades med fluorvätesyra (Ultradent). Samtliga provkroppar termocyklades (5000 cykler, mellan 5°C och 55°C) före/efter applicering av kompositmaterial. Skjuvkraftstest utfördes på alla provkroppar med belastningshastighet 0.5 mm/min. Frakturanalys utfördes där brottytorna delades in i adhesiv-, kohesiv- eller mixfraktur. Resultaten analyserades med one-way ANOVA, Tukey´s test med signifikansnivån α=0.05. Resultat: Fluorvätesyra påvisade en signifikant högre bindningsstyrka 11.32 ± 4.28  MPa i jämförelse med övriga grupper (p<0.01). Övriga gruppers medelvärde var mellan 2.61 ± 1.36 till 3.96 ± 2.85 MPa. Det fanns ingen signifikant skillnad mellan de övriga grupperna. Samtliga grupper fick adhesiva frakturer, men Voco-gruppen uppvisade även mixfrakturer.  Slutsats: Samtliga reparationssystem visar på låg bindningsstyrka och baserat på resultaten kan det inte rekommenderas. Förbehandling av porslinsyta med fluorvätesyra i kombination med silan resulterar i högst bindningsstyrka till komposit. Värdet är trots allt lågt för en god långtidsprognos, men det enda som kan rekommenderas. Det faktum att fluorvätesyra har giftiga egenskaper vore det lämpligt att fortsätta utvecklingen av reparationssystem för att hitta ett lämpligt alternativ.
Purpose: The purpose of this study is to investigate different repair systems and their bond strength to porcelain for metal-ceramic constructions. Material and method: Metal were manufactured by CAD / CAM in CoCr (5.0x5.0x15.0mm), was pretreated with sandblasting (alumina, 250 µm), steam blasting, oxidation, sandblasting and steam blasting. Feldspar porcelain was applied according to the following steps: opaque, dentin, enamel, selfglaze to a final porcelain height of 1.2 ± 0.2 mm. The porcelain surfaces were groud with silicon carbide sandpaper, 600-, 800-, 1200-grain size. Five groups (n = 15) in a total of 75 specimens. Adhesives and composite materials were applied to each group according to the instructions of the various manufacturers  (Kuraray, Kulzer, Voco, Ivoclar, Ultradent, Etching with hydrofluoric acid). All specimens were thermocycled (5000 cycles) in two water baths between 5 ° C and 55 ° C before and after application of composite material. Shear bond strength test was performed on all specimens with a load speed of 0.5 mm / min and the bond strength was reported in MPa. Fracture analysis was performed where the fracture surfaces were divided into adhesive, cohesive or mixed fracture. The results were analyzed with one-way ANOVA, Tukey´s test with significance level α= 0.05. Result: The result clearly showed that hydrofluoric acid had a significantly higher bond strength of 11.32 ± 4.28 MPa compared to the other groups (p <0.01). The mean value of the other groups was between 2.61 ± 1.36 to 3.96 ± 2.85 MPa, with  no significant difference between the groups. All groups had adhesive fractures, but the Voco-group also showed mixed fractures. Conclusion: The study concludes that all repair systems have a low bond strength and based on the results can’t be recommended. Pretreatment of the porcelain surface with hydrofluoric acid in combination with silan results in the highest bond strength to composite, the bond strength is still too low for long-term use, but the only one that can be recommended. However hydrofluoric acid is highly toxic which require further research in the field in order to develop reparation systems with suitable properties.

Introduction: A critical issue and concern that has been documented in dentistry is the complexity of bonding to dentin, a fact that has been referred to as a less reliable technique due to the intrinsic characteristics of the dentin substrate. Effectiveness on dentin bonding is a clinical important approach for indirect bonded restorations in order to achieve a good adhesion that can surpass the test of time. Long-term clinical trials have shown that indirect bonded restorations have an increased risk of failure when using dentin as the major substrate. Consequently, an effort should be made to improve techniques and materials utilized in dentin bonding to make restorations more predictable and durable. Among these efforts, Immediate Dentin Sealing (IDS) a concept introduced in the late nineties-had demonstrated outstanding in vitro outcomes when tested on dentin in the field of adhesive dentistry. Even though there is moderate evidence in support of the utilization of IDS over the conventional (DDS) approach, few studies have really emphasized on the correct utilization of IDS on indirect bonded restorations. The purpose of this study was to evaluate and compare the microtensile bond strength of coronal dentin following the application of two different techniques (IDS versus conventional) and two different dentin bonding systems (4 th and 5th generation), when using indirect bonded restorations. Methods: After Institutional Review Board (IRB) approval, extracted sound human third molars were collected. Occlusal dentinal area was used for testing. Specimens were divided into 4 groups (n=20). Group 1: IDS using a 4th generation dentin bonding system (DBS); Group 2: IDS using a 5th generation DBS; Group 3: Conventional (DDS) using a 4 th generation DBS; and Group 4: DDS using a 5th generation DBS. All specimens were restored using a light-cure indirect micro ceramic/composite restorative material and stored on moist environment for 24 hours before testing. Each tooth was sectioned perpendicular to the bonding interface 1 x 1 x 10 mm beams. Specimens were subjected to microtensile bond strength test (μTBS). Statistical analysis was done using ANOVA comparing technique and bonding system. Results: For bonding techniques, the conventional technique exhibited lower strength than IDS, this difference being statistically significant (p = 0.0100). When bonding systems were compared 4th generation (Optibond FL) and 5th generation (Optibond Solo Plus), the higher mean was found with the 5th generation which was statistically significant (p =0.0121). In the conventional group when 4th generation and 5th generation are compared, the bond strength in the 5th generation was higher with this difference being statistically significant (p = 0.0024). In the IDS group, the bond strength was higher again in the 5th generation, however this difference was not statistically significant (p = 0.18). The results of two-way ANOVA for bonding system and technique, and interaction showed significant main effect for technique (p = 0.007) and dentin bonding system (p = 0.010). No significant interaction effect was found for dentin bonding system by technique (p = 0.797). Conclusions: The immediate dentin sealing IDS performed better than the conventional. The 5th generation bonding system performed better than the 4th generation bonding system. Restorative approach or technique immediate dentin sealing IDS versus conventional will increase significantly the bond strength of the dentin to indirect composite restorations of the tested adhesive systems.

December 2011. A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Introduction: The purpose of this study is to compare the shear bond strengths (SBSs) of two new commercial adhesive systems to a conventional multistep bonding system incorporating a 35% phosphoric acid gel. In addition, the amount of adhesive remaining on each tooth following debonding will be analyzed and compared using the adhesive remnant index (ARI). Methods: 88 human premolar teeth chosen from the Nova Southeastern tooth databank were randomly divided into four groups. Group I (control group): Transbond XT primer and adhesive (35% phosphoric acid), Group II: iBond Total Etch system with iBond 35 gel (35% phosphoric acid), Group III: iBond Total Etch system with iBond 20 gel (20% phosphoric acid). Group IV: iBond Self Etch. A scanning electron microscope (SEM) was utilized to qualitatively examine the enamel surface of one randomly selected tooth per group immediately after etching, leaving 21 teeth per group available for the debonding procedure (n=21). Following bonding of the stainless steel brackets (3M Unitek, Monrovia, CA), the teeth were stored in water at 37°C ± 2°C for forty-eight hours. A universal testing machine (Instron, Canton, MA) was then used to determine the shear bond strength of each bracket. Additionally, the amount of adhesive remaining on each tooth following debonding was recorded using 10x light microscopy. Results: A 1-way ANOVA revealed that no statistical differences in bond strength were found between the four groups. SBS values of groups I (11.7 ± 3.9), II (11.6 ± 4.6), III (10.3 ± 4.1), and IV (10.8 ± 3.9) demonstrated mean SBSs considered adequate. The iBond Total Etch (20%) and iBond Total Etch (35%) groups were more likely to have an ARI score of 2-3 than the control group (Transbond XT). No significant differences were found between iBond Self Etch and the control group. Conclusion: The SBS's of all three groups, as compared to the control group, were adequate. The iBond Total Etch system, whether used with iBond 20 gel or iBond 35 gel, had more adhesive remaining on the tooth surface after debonding. Standardization amongst shear bond strength studies is significantly needed in the near future in order to accurately compare findings.

Background . Little is known about the long-term clinical bonding effectiveness of the Fiber-reinforced composite (FRC) posts cemented with self-etch adhesive systems. Bond stability and longevity of the cemented post are adversely affected by physical and chemical factors over time, such as expansion and contraction stresses caused by thermal changes and occlusal load. This clinical condition can be simulated in vitro by thermocyclic loading; and bonding effectiveness can be evaluated by applying the micropush out test. Therefore, more in vitro studies are needed to evaluate the bond strength of the fiber posts cemented with different resin cement systems after simulating the artificial aging induced by thermocycling. The aim of this study was to compare the microtensile bond strength of two different resin cement systems (total etch, and self-etch resin cement system) used for cementation of fiber reinforced composite posts in three different aging periods using thermocycling. Methods . Following IRB approval, sixty freshly extracted bicuspid single rooted natural teeth were endodontically treated, and the post-spaces were prepared to receive a fiber-post cemented with either a total etch resin cement (Rely-X Ultimate) or with a self-etch resin cement (Rely-X Unicem). No thermocycling, 20,000 and 40,000 cycles was used to age the specimens. Teeth were randomly allocated into six different groups: G1 - Control: Rely-X Ultimate cement with no thermocycling. G2: Rely-X Ultimate cement with 20,000 thermocycling. G3: Rely-X Ultimate cement with 40,000 thermocycling. G4: Rely-X Unicem cement. G5: Rely-X Unicem cement. G6: Rely-X Unicem cement. Microtensile bond strength determined using a micropush out test on a universal testing machine (MTS). Additionally, the failure mode of each specimen was observed under a stereomicroscope (Olympus) at 40x magnification. Finally, one representative sample was randomly selected from each of the five failure modes for scanning electron microscope (SEM) examination of the surface morphology in order to obtain SEM images of the failure patterns at 29-70x magnifications. Statistical analysis: Nested general linear and generalized linear model was created to look for statistical significance. Level of significance was set at P < 0.05. Results . No significant differences were found on the bond strength between the two types of resin cement systems (total etch and self-etch). Regarding the thermocycling effect, the bond strengths of the group of 40,000 cycles was significantly lower than the 20,000 cycle group. In addition, the bond strengths of the specimens collected from the coronal third of the root were significantly lower than the specimens from the apical third. A Fisher's Exact test was applied to evaluate the failure mode differences, and showed statistically significant differences between the groups. Conclusions . The bond strength to the root canal dentin did not vary with the type of resin cement systems (total-etch vs self-etch). The microtensile bond strength values of FRC posts were significantly affected by increasing the thermocycling, and were significantly different among the different longitudinal levels of the root canal.

Introduction: Orthodontic treatment may cause an increased accumulation of cariogenic bacteria. An orthodontic resin with antibacterial properties may inhibit bacterial growth around the brackets. The aims of this in-vitro study were to compare the antibacterial and mechanical properties of the newly introduced orthodontic resin containing selenium with a standard resin and a resin modified glass ionomer (RMGI). Methods: Three orthodontic materials were tested (SeLECTDefense; TransbondXT, Fuji Ortho-LC). The antibacterial properties of these materials were evaluated by studying the bacterial growth in liquid media (BG) and agar diffusion (AD) tests. In the BG testing, 100 adhesive discs (3mmx2mm) were created of each material. Five discs were then placed into each vial containing 0.5ml of brain-heart-infusion broth and 2.5µl of streptococcus mutans (MS)(n=20). Following incubation (37°C, 24hours), the vials were placed in a Spectrophotomoter (Genesys 20) at 600 nm to determine bacterial growth by measuring the optical density (OD). In the AG testing, agar plates were inoculated with 100µl of MS in brain heart infusion agar. Fifteen adhesive discs (6mmx2mm) of each material were prepared and placed into groups of five on 3 agar plates. Following incubation (37°C, 48 hours), the agar plates were visually inspected for zones of bacterial inhibition. The mechanical properties were evaluated using shear bond strength testing (SBS) and an adhesive remnant index scoring (ARI). Sixty human premolars were randomly assorted into groups of 20 for each material (n=20). The brackets were bonded following the manufacturers' instructions. Debonding was performed using a universal testing device (Instron)(crossheadspeed 5mm/min). The mode of failure was evaluated using a stereomicroscope (OlympusSZX7) and scored 0-to-3 for remaining adhesive on enamel. Results were statistically analyzed using Welsch's ANOVA, One way ANOVA, Tukey's Kramer and Tukey's HSD tests. Results: In BG, the resin containing selenium (SD) promoted more bacterial growth (OD=0.427) compared to the standard resin (XT) (OD= 0.222) and RMGI (OD=0.275). In AD, no zones of inhibition were observed which means that no antibacterial agent was released from any of the orthodontic adhesives. In SBS, SD (11.63±2.07MPa) showed statistically lower bond strength than XT (15.16±4.68MPa) but both resins were in the clinically acceptable range. RMGI (6.03±3.95MPa) showed a statistically lower bond strength at a clinically unacceptable degree. Debonding was mostly at the bracket-adhesive interface for SD (ARI=2&3) meaning that most of the adhesive remained on the enamel. In XT and RMGI groups, debonding occurred mostly at the adhesive-enamel interfaces (ARI=0&1). Conclusion: Within the limitations of this in vitro study, the resin containing selenium did not show any favorable antibacterial properties in comparison to the other materials. None of the materials, including fluoride-releasing RMGI, caused bacterial inhibition in their surroundings. The resin containing selenium showed clinically acceptable but statistically lower bond strength as compared to standard resin but its mode of failure was more favorable because most of the adhesive remained on enamel.

Este trabalho teve o objetivo de avaliar a resistência adesiva de sistemas adesivos baseados no condicionamento prévio com ácido fosfórico (etch-and-rinse) e auto-condicionantes (de um e dois passos) ao substrato dental, submetido a diferentes condições de irradiação com laser de Er,Cr:YSGG. Amostras de esmalte e dentina foram obtidas do terço médio da face vestibular de 216 incisivos bovinos, divididos aleatoriamente em 18 grupos (n=12), de acordo com o substrato, (esmalte e dentina), sistema adesivo (etch-and-rinse, auto-condicionante de um passo e auto-condicionante de dois passos) e condições de irradiação (sem irradiação ? controle, irradiado com refrigeração ar-água e irradiado sem refrigeração ar-água). Em seguida foi realizada inclusão e polimento, sob refrigeração, com lixas de carbeto de silício de granulação decrescente 180, 320, 400 e 600 (por um minuto para padronização da camada de esfregaço). Para os grupos irradiados com laser de Er,Cr:YSGG (?=2,79 ?m, taxa de repetição de 20 Hz), com densidade de energia de 2,8 J/cm2, 12,5 mJ por pulso, potência média de 0,25W, com a ponta S75 de diâmetro de 750 ?m a 1 mm da superfície do substrato. A condição de refrigeração da irradiação foi realizada com 11 mL/min. Os corpos-de-prova foram confeccionados com a resina composta Filtek Z250, em forma de cone invertido para realização do teste de resistência adesiva. Após 24 h de armazenagem em água destilada a 37ºC, fez-se o ensaio de tração a 0,5 mm/min. Os dados foram comparados estatisticamente pelo método de ANOVA com significância de 5%. Os resultados obtidos mostraram que para o tecido esmalte foi observada diferença estatisticamente significante para os fatores adesivo e condições de irradiação empregadas, sem significância para a interação entre os fatores. A resistência de união do sistema adesivo auto-condicionante de dois passos e do sistema adesivo etch-and-rinse apresentam desempenho semelhante, sendo superiores ao sistema adesivo auto-condicionante de passo único. Ainda para esmalte, o efeito das condições de irradiação mostrou que os grupos sem irradiação com laser de Er,Cr:YSGG apresentaram maior resistência adesiva do que os grupos irradiados com refrigeração e sem refrigeração. Para o substrato dentina, houve diferença estatisticamente significante para os fatores de variação principais: sistemas adesivos, condição de irradiação com laser de Er,Cr:YSGG e para a interação adesivo X condição de irradiação. Quanto à comparação entre os sistemas adesivos testados na condição sem irradiação, os sistemas adesivos auto-condicionantes, de dois passos e o de um passo, não foram estatisticamente diferentes entre si, porém ambos forneceram resultados de resistência adesiva estatisticamente menores do que o sistema adesivo etch-and-rinse. Para as condições de irradiação com laser de Er,Cr:YSGG, com refrigeração e sem refrigeração, obteve-se valores de resistência adesiva maiores para o sistema auto-condicionante de dois passos do que para os demais sistemas. Deste modo, conclui-se que a irradiação com laser de Er,Cr:YSGG reduz a adesão ao esmalte independentemente do sistema adesivo utilizado e da condição de irradiação. Adicionalmente, observa-se que a irradiação de dentina com laser de Er,Cr:YSGG somente não altera a resistência adesiva do sistema auto-condicionante de dois passos, sendo deletéria aos demais adesivos testados.
The aim of this study was to assess the bond strength to dental substrate of adhesives based on previous etching with phosphoric acid (etch-and-rinse) and self-etching (one- and two-step) under different conditions of Er,Cr:YSGG laser irradiation. Enamel and dentin samples were obtained from the middle third of the buccal face of 216 bovine incisors, randomly divided in 18 groups (n=12), according to the substrate (enamel and dentin), adhesive system (etch-and-rinse, one-step self-etching and two-step self-etching) and irradiation condition (without irradiation ? control, irradiated with cooling, and irradiated without cooling). Next, the samples were included and polished, under cooling, with silicone carbide abrasive papers of decreasing grit #180, 320, 400 and 600 (for one minute to standardize the smear layer). For the irradiated groups with Er,Cr:YSGG laser, an energy density of 2.8 J/cm2, 12.5 mJ per pulse, mean power of 0.25W was selected. During laser irradiation, cooling was performed with 11 mL/min. Inverted cone-shaped test specimens were built-up with resin composite Filtek Z250, for performing the bond strength test. After 24 h storage in distilled water at 37ºC, the tensile test was performed at 0.5 mm/min. The results obtained show, for enamel, statistically significant difference for the factors adhesive and irradiation conditions used, without significance for the interaction among the factors. The bond strength of the 2-step self-etching and the etch-and-rinse adhesive system presented similar performance, being superior to that of one-step self-etching system. For enamel, the effect of the irradiation conditions showed that the groups without Er,Cr:YSGG laser irradiation presented higher bond strength than the groups irradiated with and without cooling. For the dentin substrate there was statistically significant difference for the main variation factors: adhesive systems, condition of Er,Cr:YSGG laser irradiation and for the interaction adhesive X irradiation condition. As regards the comparison among the adhesive systems tested under the condition without irradiation, the one-step and two-step self-etching adhesive systems did not differ statistically between them, but both provided statistically lower bond strength results than the etch-and-rinse adhesive system. For the condition of Er,Cr:YSGG laser irradiation with and without cooling, higher bond strength values were obtained for the two-step self-etching system than for the other systems. Therefore, it was concluded that Er,Cr:YSGG laser irradiation reduces the bond strength to enamel irrespective of the adhesive system used and the irradiation condition. Furthermore, it was observed that dentin irradiated with Er,Cr:YSGG laser did not alter the bond strength of the two-step adhesive system only, and it was deleterious to the other adhesives tested.

Oral Biology
M.S.
Objective: Prior to the advent of bonded orthodontic appliances each tooth was fitted with a band made from stainless steel. Traditionally they were cemented to the tooth with a zinc phosphate cement. This acted more as a luting agent then adding to the actual adherence of the band to the tooth. In addition, often times the cement would wash out and upon the band removal white spot lesions and or carious lesions were present. The development of glass monomer cements had a traumatic improvement over both the adhesion to the tooth and a diminishing of white spot lesions in part due to the release of fluoride. Since the advent of the acid-etch technique and the bonding of orthodontic brackets directly to the enamel various bonding adhesives were developed. The first and most popular bonding resins were chemical curing bonding systems. The general class of self-adhesive and/or self-etching orthodontic adhesives are of several types, including resin-modified cements, such as resin-modified glass ionomer cements, that exhibit self-adhesive properties to enamel, as well as self-etching primers that combine the conditioning and priming agents into one acidic, polymerizable composition for application to the tooth surface, and do not require separate etching and rinsing steps. Not only do resin modified glass ionomers have the benefit of chemically bonding to a clean and un-etched enamel surface, but these self-adhesive cements also release significant and continuous levels of fluoride ion. Recently investigators have explored adding antimicrobial agents in addition to fluoride in orthodontic adhesives. One such approach has been the addition of ZnO powder, a known compound with anti-microbial properties, to an orthodontic resin modified glass ionomer adhesive. It should also be noted that zinc ions and compounds have been shown to positively influence enamel remineralization and enhance apatite formation. The objective of this research is to evaluate the effect of the addition of an antimicrobial agent, zinc oxide powder, on selected mechanical properties of a resin modified glass ionomer orthodontic adhesive. Methods: A resin modified glass ionomer (Fuji Ortho LC), in its two-component, powder/liquid format were utilized in this study. Control specimens, according to manufacturer's directions for use, were prepared for both diametral tensile and microhardness testing with be prepared. Using the powder component provided in the marketed product; powder blends containing both 10 and 20 percent Zinc Oxide (by weight) will be added to the RMGI powder, and thoroughly mixed and blended to create a uniform powder blend. The mechanical testing will be performed on 8-10 disc specimens, approximately 6.2 mm diameter by 3.1 mm in height, using a standardized mixing and molds for each material. The specimens will be tested using the Instron 5569 testing machine at a crosshead speed of 0.75 mm/minute for DTS until failure occurs. Data was recorded in Newton’s (N) force. The microhardness testing was performed on 12 disc specimens, approximately 6.2 mm diameter by 3.1 mm in height, using a standardized mixing and molds for each material. A CSM microindentation testing device was used to measure theVickers microhardness. The surface morphological evaluation of the specimens both control and experimental will be examined at 50 X magnification for comparison of surface characteristics and morphology. One-way ANOVA for comparison of time- and material-specific mean Vickers microhardness values and post hoc pair-wise comparisons was employed to assess statistically significant differences in the mean values (p<0.05). Results: The diametral tensile strength test of all specimens including the modified control and experimental showed incremental decreases in the DTS as compared to the control mixed as per the manufacturer’s specifications. The Vickers values illustrated minimal variation of Vickers microhardness for the control and experimental group. The surface morphological evaluation illustrated various differences between the control, modified control and the Zinc Oxide formulations. Conclusions: Alterations in the liquid powder ration of the orthodontic resin modified glass ionomer adhesive resulted in a reduction of the DTS. The addition of both 10% and 20% zinc oxide powder also resulted in a significant reduction of the DTS as compared to the manufacturers mix proportions of liquid and powder. The Vickers microhardness did not illustrate a significant alteration in any of the specimens. The addition of both 10% and 20% zinc oxide powder to the mixture reduced the modulus and stiffness as compared to both of the control groups. Lastly, the morphology of the experimental samples with the zinc oxide showed a more irregular surface at the fracture site.
Temple University--Theses

The effect of phosphate functionality and dentin surface state on adhesion to dentin was investigated in a series of experiments. In all cases, variable effects were evaluated by measuring the strength of adhesion promoted by either of two priming agents, (PENTA, or DIPENTA), or their combination, to different surface conditions of dentin. The main difference between primers is the presence of a phosphate functionality in PENTA. These experiments demonstrated that the phosphate-containing primer promotes significantly greater adhesion compared to the non-phosphate containing primer for all surface states studied. They further showed that on demineralized dentin, strong adhesion for PENTA may be due to phosphate interaction with collagen and the mineral aptatite of unaltered dentin. Finally, phosphate bonds to either intact or demineralized dentin were relatively stable in the presence of water. We conclude that for the adhesion promoter studied, the interaction of a phosphate functionality with organic and inorganic components of dentin promotes a strong and durable adhesive joint.

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP; Faculdade de Odontologia, Universidade de Sao Paulo, Sao Paulo

Over 200 million dental restorations are performed each year in America. A dental restoration require a strong bonding of restoration to tooth structure and relies on the dental adhesive to create this mechanical and chemical bonding. Dental adhesion or bonding is the process of forming an adhesive joint between the composite and tooth substrate: dentin or enamel. Clinical problems such as microleakage at the restoration tooth interface, influx of fluids, or bacteria growth at the cavity wall can be prevented with adhesives that obtain a more intimate bonding. Longevity of the restoration can be enhanced by the adhesive that creates the tight bonding to reduce problems such as postoperative sensitivity, marginal staining, and recurrent caries. The goal of this research project is to investigate the influence of active scrubbing application as compared to passive non-scrubbing application of the etchant component in 4th generation etch-and-rinse adhesive systems. Shear bond stresses have been measured and compared between application techniques. Verification of resin infiltration depth with each etchant application has been examined with scanning electron microscopy by mounting the etched and bonded enamel surface of the tooth in epoxy and slicing the tooth longitudinally producing a transverse, depth-wise view. Results from this study have clarified the role of resin tag formation as well as tooth morphology during an active acid etchant application for dental restoration.

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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Thesis (Ph.D.)--Tufts University, 1999.
Submitted to the Dept. of Mechanical Engineering. Includes bibliographical references (leaves 110-113). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

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Os adesivos a base de cianoacrilato são utilizados em cirurgia oral e maxilofacial para fechamento de feridas cirúrgicas, comunicação buco-sinusal, reparo de fissura labial e osteosíntese do esqueleto craniofacial. O objetivo deste trabalho foi comparar três métodos de fixação (etil-cianoacrilato, n-butil-cianoacrilato ou parafuso de titânio) do enxerto ósseo autógeno (EOA) em bloco. Foram realizadas ostectomias bilaterais na região parietal em trinta coelhos com uma trefina de 6mm para obtenção do EOA. Os EOA em bloco obtidos foram fixados com etil-cianoacrilato (Grupo I), n-butil-cianoacrilato (Grupo II) ou parafuso de titânio (Grupo III). Os animais foram sacrificados nos períodos de cinco, quinze, trinta, sessenta e cento e vinte dias, sendo obtidas amostras da região do EOA. As peças foram processadas em laboratório de acordo com o método histotécnico de rotina e coradas com hematoxilina e eosina. Os eventos histológicos avaliados foram: infiltrado inflamatório, reabsorção do adesivo e neoformação e reabsorção óssea. Os resultados dos eventos celulares foram submetidos ao teste de Kruskal-Wallis, seguido pelo teste de Dunn para determinar as diferenças entre os grupos (p < 0.05). A análise qualitativa ordinal mostrou a presença de infiltrado inflamatório e reabsorção óssea mais significativos nos grupos I e II, principalmente nos períodos iniciais. O infiltrado inflamatório observado no grupo controle foi discreto (p<0.05). O processo de reabsorção do adesivo foi semelhante, não havendo diferença estatística (p>0.05). No período de 120 dias, foi possível observar adesivo na interface EOA-leito receptor. A neoformação óssea foi mais intensa no grupo controle e no período de 120 dias, o EOA em bloco...
Cyanoacrylates are used in oral and maxillofacial surgery for closure of surgical wounds, oroantral communication, cleft lip repair, and osteosynthesis of the craniofacial skeleton. The aim of this study was compare three fixation methods (ethyl-cyanoacrylate, n-butyl cyanoacrylate or titanium screw) of autogenous onlay bone graft (AOBG). Bilateral ostectomies were made in the parietal region in thirty rabbits using a 6-mm-diameter trephine. The AOBG was fixed with ethyl-cyanoacrylate (Group I), n-butyl cyanoacrylate (Group II) or titanium screw (Group III - control). The animals were sacrificed at five, fifteen, thirty, sixty, and one hundred and twenty days, and the samples were obtained from AOBG region. The processing was done in accordance with the method histotechnical and stained with hematoxylin and eosin. The evaluated histological events were: inflammatory infiltrate, adhesive resorption and bone formation and bone resorption. The results of cellular events were subjected to the Kruskal-Wallis test followed by Dunn's test to determine differences between groups (p <0.05). The qualitative numerical analysis showed the presence of inflammatory infiltrate and significant bone resorption in groups I and II, especially in the early periods. The inflammatory infiltrate seen in the control group was discrete (p <0.05). The adhesive reabsorption process was similar, with no statistical difference (p> 0.05). After 120 days, we observed residual adhesive between AOBG ...

Orientador: Eduardo Hochuli Vieira
Banca: Roberta Okamoto
Banca: Idelmo Rangel Garcia Júnior
Banca: Eduardo Sanches Gonçales
Banca: Cássio Edvard Sverzut
Resumo: Os adesivos a base de cianoacrilato são utilizados em cirurgia oral e maxilofacial para fechamento de feridas cirúrgicas, comunicação buco-sinusal, reparo de fissura labial e osteosíntese do esqueleto craniofacial. O objetivo deste trabalho foi comparar três métodos de fixação (etil-cianoacrilato, n-butil-cianoacrilato ou parafuso de titânio) do enxerto ósseo autógeno (EOA) em bloco. Foram realizadas ostectomias bilaterais na região parietal em trinta coelhos com uma trefina de 6mm para obtenção do EOA. Os EOA em bloco obtidos foram fixados com etil-cianoacrilato (Grupo I), n-butil-cianoacrilato (Grupo II) ou parafuso de titânio (Grupo III). Os animais foram sacrificados nos períodos de cinco, quinze, trinta, sessenta e cento e vinte dias, sendo obtidas amostras da região do EOA. As peças foram processadas em laboratório de acordo com o método histotécnico de rotina e coradas com hematoxilina e eosina. Os eventos histológicos avaliados foram: infiltrado inflamatório, reabsorção do adesivo e neoformação e reabsorção óssea. Os resultados dos eventos celulares foram submetidos ao teste de Kruskal-Wallis, seguido pelo teste de Dunn para determinar as diferenças entre os grupos (p < 0.05). A análise qualitativa ordinal mostrou a presença de infiltrado inflamatório e reabsorção óssea mais significativos nos grupos I e II, principalmente nos períodos iniciais. O infiltrado inflamatório observado no grupo controle foi discreto (p<0.05). O processo de reabsorção do adesivo foi semelhante, não havendo diferença estatística (p>0.05). No período de 120 dias, foi possível observar adesivo na interface EOA-leito receptor. A neoformação óssea foi mais intensa no grupo controle e no período de 120 dias, o EOA em bloco...
Abstract: Cyanoacrylates are used in oral and maxillofacial surgery for closure of surgical wounds, oroantral communication, cleft lip repair, and osteosynthesis of the craniofacial skeleton. The aim of this study was compare three fixation methods (ethyl-cyanoacrylate, n-butyl cyanoacrylate or titanium screw) of autogenous onlay bone graft (AOBG). Bilateral ostectomies were made in the parietal region in thirty rabbits using a 6-mm-diameter trephine. The AOBG was fixed with ethyl-cyanoacrylate (Group I), n-butyl cyanoacrylate (Group II) or titanium screw (Group III - control). The animals were sacrificed at five, fifteen, thirty, sixty, and one hundred and twenty days, and the samples were obtained from AOBG region. The processing was done in accordance with the method histotechnical and stained with hematoxylin and eosin. The evaluated histological events were: inflammatory infiltrate, adhesive resorption and bone formation and bone resorption. The results of cellular events were subjected to the Kruskal-Wallis test followed by Dunn's test to determine differences between groups (p <0.05). The qualitative numerical analysis showed the presence of inflammatory infiltrate and significant bone resorption in groups I and II, especially in the early periods. The inflammatory infiltrate seen in the control group was discrete (p <0.05). The adhesive reabsorption process was similar, with no statistical difference (p> 0.05). After 120 days, we observed residual adhesive between AOBG ...
Doutor

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Orientador: Giselle Maria Marchi Baron
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Atualmente no mercado, muitos são os aparelhos utilizados para fotoativação das restaurações em resina composta. Uma polimerização adequada é essencial para obtenção de restaurações com propriedades físico-mecânicas ideais e resistentes aos desafios encontrados no meio bucal. Os objetivos deste estudo foram avaliar a influência do tipo de fonte fotoativadora e meios de envelhecimento sobre a propriedade de dureza Knoop e integridade marginal de restaurações em resina composta. Cavidades proximais (4,5x6,0x1,5mm) com margem cervical em dentina foram confeccionadas em uma das faces proximais de 240 incisivos bovinos. Estes dentes foram divididos em 6 grupos (n=40) conforme o meio de envelhecimento a ser empregado após restauração: C ? sem envelhecimento (controle); TC ? envelhecimento térmico (1000 ciclos: 5±2C / 55±2Coo); CM ? envelhecimento mecânico (200.000 ciclos: 75N / 2Hz ); CM/TC ? associação de envelhecimento mecânico e térmico; 1A ? estocagem por 1 ano em solução de Hank; e CM/TC/1A ? associação de envelhecimento mecânico, térmico e estocagem por 1 ano em solução de Hank. Posteriormente, os dentes foram sub-divididos em 4 grupos (n=10) de acordo com aparelho fotoativador utilizado: HAL ? Lâmpada Halógena ? Optilux 501 (Demetron); LED ? LED azul ? Elipar FreeLight 2 (3M ESPE); LAS ? Laser de Argônio ? AccCure 3000 (LaserMed) e PAC ? Arco de Plasma de Xenônio ? Apollo 95E Elite (DMD) . O tempo de foto-emissão foi calculado para cada aparelho, para que a densidade de energia emitida fosse de 6,04J/cm2. As restaurações foram realizadas utilizando o sistema adesivo Single Bond (3M ESPE) e a resina composta microhíbrida Filtek Z250 (3M ESPE) em 3 incrementos. Após 24h, realizou-se o acabamento e polimento das restaurações. Moldes em silicone de adição Aquasil ULV (Dentsply DeTrey) foram realizados antes e depois das restaurações serem submetidas aos meios de envelhecimento para obtenção de réplicas em resina epóxica para análise do tamanho (µm) e presença (%) de fenda na margem cervical através de microscopia eletrônica de varredura (500-1000x). Os dados foram registrados e submetidos à análise de variância em parcela subdividida e teste não paramétrico para dados pareados. Em seguida, os dentes foram segmentados com disco diamantado sob refrigeração para obtenção de fatias. Nestas fatias foi realizada a análise de microdureza Knoop (25g; 20s) em profundidade, nos seguintes terços da restauração: (C) cervical, (M) médio e (O) ?oclusal?. Os dados obtidos foram submetidos à análise de variância em parcela sub-subdividida. Não houve diferença entre as fontes de luz quanto aos valores de dureza das restaurações, sendo que, em relação à profundidade de polimerização, temos que O>M>C (ANOVA/Tukey; ?=5%). Antes do envelhecimento, não houve diferença entre as fontes de luz em relação ao tamanho e porcentagem de fendas. Após envelhecimento, houve aumento significativo no tamanho e porcentagem de fendas (Wilcoxon das ordens assinaladas; Teste t de Student). PAC e LAS apresentaram maior porcentagem de fendas que HAL; e PAC maior tamanho de fendas que LED e HAL (ANOVA/Tukey; ?=5%). Nenhuma fonte de luz foi capaz de polimerizar, com a mesma proporção, as diferentes profundidades das restaurações em resina composta e manter a qualidade do selamento marginal em dentina após os meios de envelhecimento
Abstract: At present, many light curing devices used in composite restorations are available in the market. Sufficient polymerization is crucial in order to obtain restorations with proper physical and mechanical properties, and resistance against oral environment challenges. The aims of the present study were to evaluate the influence of photo-curing devices and aging types on Knoop microhardness and marginal integrity of composite resin restorations. Proximal cavities (4.5x6.0x1.5mm) with cervical margin in dentin were prepared in 240 bovine incisors. These teeth were allocated into 6 groups (n=40) according to the type of aging applied after composite built up: C ? no aging (control); TC ? thermal aging (1000 cycles: 5±2C/55±2Coo); CM ? mechanical aging (200,000 cycles: 75N/2Hz ); CM/TC ? association between mechanical and thermal aging; 1A ? one year storage in Hank solution and CM/TC/1A ? association of mechanical and thermal aging with one year of storage in Hank solution. Further, the teeth were subdivided in 4 groups (n=10), according to the unit used for light curing: HAL ? Halogen Lamp ? Optilux 501 (Demetron); LED ? Blue LED? Elipar FreeLight 2 (3M ESPE); LAS ? Argon Laser ? AccCure 3000 (LaserMed) and PAC ? Xenon Plasma Arc ? Apollo 95E Elite (DMD) . The time of light emission was calculated for each device, so that the energy density was 6,04J/cm2. The adhesive system Single Bond (3M ESPE) and the composite resin Filtek Z250 (3M ESPE) were used for the restorations. The composite resin was applied in 3 increments of 2mm each. After 24h, restorations were finished and polished. Aquasil ULV (Dentsply DeTrey) addition silicone impressions were taken from the restorations before and after each type of aging, so that epoxy resin replicas could be obtained for marginal gap evaluation at SEM (500-1000x) in terms of length (µm) and incidence (%). The data were registered and submitted to repeated variance analysis and non parametric test. Then, teeth were cut in slabs with a diamond disc under water cooling. The slab was used for Knoop microhardness test (25g; 20s) in depth, related to the following restorations thirds: (C) cervical, (M) middle and (O) oclusal. The data were submitted to repeated variance analysis. Microhardness results did not show any difference among the photo-curing devices, however, it was dependent on the cavity depth: O>M>C (Repeated measures ANOVA/Tukey; alfa=5%). Prior to aging, there was no difference among curing light sources related to gaps length and incidence. Following aging, there was significant increase on gaps length and incidence (Wilcoxon signed rank; Student?s t). PAC and LAS showed gap percentage higher than HAL; also, PAC presented gap length greater than HAL and LED (ANOVA/Tukey; alfa=5%). None of the curing light sources was able to polymerize with the same proportion the different depths of composite restorations, as well as, to maintain the quality of marginal sealing in dentin after aging
Mestrado
Dentística
Mestre em Clínica Odontológica

Orientador: Mario Fernando de Goes
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Na tentativa de prolongar a durabilidade da união resina-dentina, a clorexidina aparece como uma alternativa para preservar a integridade do componente colágeno não envolvido pela camada híbrida. O presente estudo teve como objetivo avaliar o efeito da clorexidina na interação entre o adesivo autocondicionante de dois frascos Adper SE Plus (3M ESPE) e a dentina nas variáveis: a) resistência de união (RU) após 1 dia, 3 meses e 6 meses de armazenamento em água, e b) padrão de fratura. Foram obtidos oito terceiros molares humanos recém extraídos e livres de cárie. O esmalte oclusal e a raiz foram removidos para obter um bloco de dentina de 4mm de espessura com uma superfície plana em dentina média. Cada bloco foi cortado longitudinalmente em duas metades resultando em oito hemiblocos para cada um dos Grupos Controle (C) e Experimental (CHX). Para o Grupo Controle, o Adper SE Plus foi aplicado seguindo as instruções do fabricante: 1 - aplicação do Líquido A, 2 - aplicação ativa do Líquido B por 20s, 3 - leve jato de ar comprimido durante 10s, 4 - aplicação de uma segunda camada de Líquido B, 5 - leve jato de ar comprimido. O adesivo foi fotoativado durante 10s usando a unidade de luz visível Elipar Freelight 2 (3M ESPE) com intensidade de 900 mW/cm2. Para o Grupo Experimental, foi realizado o mesmo procedimento substituindo o Líquido A por uma solução aquosa de digluconato de clorexidina a 2% em peso. Foram construídos blocos de resina composta Filtek Z250 (3M ESPE) sobre a dentina em seis incrementos de 1mm sendo fotoativados durante 20s cada. Depois de 24 horas de armazenamento em água destilada a 37°C, os hemiblocos restaurados foram seccionados perpendiculares à região adesiva nos sentidos mesiodistal e bucolingual e obtidos de 8 a 10 palitos de 0,9mm2 (±0,2mm2), os quais foram divididos aleatoriamente em três grupos de 2 a 4 palitos cada e avaliados após 1 dia, 3 meses e 6 meses de armazenamento em água destilada a 37°C. Para o teste de microtração cada palito foi submetido à tração sob velocidade de 0,5mm/min em uma máquina de ensaios universais. Os valores de RU foram submetidos à Análise de Variância de dois fatores para medidas repetidas (?=0,05), e os padrões de fratura classificados em Microscópio Eletrônico de Varredura. O Grupo Controle apresentou valores de RU estatisticamente não diferentes entre si após 1 dia, 3 meses e 6 meses de armazenamento (46,43±11,46 MPa; 50,02±13,84 MPa; 45,18±17,92 MPa, respectivamente). Os valores de RU do Grupo Experimental também resultaram estatisticamente não diferentes entre si nos mesmos tempos de armazenamento (37,22±10,45 MPa; 47,29±12,67 MPa; 40,22±10,01 MPa, respectivamente). Não houve diferença estatística nos valores de RU entre os Grupos Controle e Experimental. Houve predominância de padrões de fraturas coesiva no adesivo, e mista coesiva no adesivo e na resina composta em ambos os grupos e em todos os tempos de armazenamento. Dentro das condições deste estudo, conclui-se que a RU à dentina do Adper SE Plus não diminuiu com o tempo, e não foi negativamente afetada pela clorexidina a 2%
Abstract: In the search for durability of resin-dentin bond, chlorhexidine appears as an alternative to preserve integrity of collagen component not involved by the hybrid layer. This study aimed to evaluate the effect of chlorhexidine in the interaction between two-bottle self-etching adhesive Adper SE Plus (3M ESPE) and dentin, in terms of bond strength (BS) after 1 day, 3 months and 6 months of water storage, and fracture mode analysis. Eight fresh caries-free human third molars were obtained. The occlusal enamel and roots were removed to obtain a 4mm-thick dentin block with a flat surface in middle dentin. Each dentin block was cut longitudinally into halves resulting in eight hemi-blocks for each of the Control (C) and Experimental (CHX) Groups. For the Control Group, Adper SE Plus was applied following the manufacturer's instructions: 1 - application of Liquid A, 2 - active application of Liquid B for 20s, 3 - gentle compressed air stream for 10s, 4 - application of a second layer of Liquid B, 5 - gentle compressed air stream. The adhesive was light cured for 10s using light unit Elipar Freelight 2 (3M ESPE) with a minimum intensity of 900 mW/cm2. For the Experimental Group, it was performed the same procedure replacing the Liquid A with a solution of 2 wt% chlorhexidine digluconate. Resin composite build-ups were constructed with Filtek Z250 resin composite (3M ESPE) in six increments of 1mm and were light cured for 20s each. After 24 hours storage in distilled water at 37°C, restored hemi-blocks were sectioned perpendicular to the adhesive region in mesiodistal and buccolingual directions and were obtained 8 to 10 beams of 0.9mm2 (±0.2mm2), which were randomly divided into three groups of 2 to 4 beams and evaluated after 1 day, 3 months and 6 months of storage in distilled water at 37°C. For the microtensile test, each beam was tested on tensile until failure at a crosshead speed of 0.5mm/min in a universal testing machine. The BS values were subjected to two-way repeated measures ANOVA (?=0.05), and fracture mode classified in Scanning Electron Microscope. The Control Group had BS values not statistically different from each other after 1 day, 3 months and 6 months of storage (46,43±11,46 MPa; 50,02±13,84 MPa; 45,18±17,92 MPa, respectively). The BS in the Experimental Group also resulted not statistically different from each other at the same times of storage (37,22±10,45 MPa; 47,29±12,67 MPa; 40,22±10,01 MPa, respectively). There was no statistical difference in BS values between Control and Experimental Groups. There was a predominance of cohesive failure within adhesive resin, and mixed cohesive failure within adhesive resin and resin composite in both groups at all storage times. Under the conditions of this study, it can be concluded that BS of Adper SE Plus to dentin did not diminish with time, and was not adversely affected by 2% chlorhexidine
Mestrado
Materiais Dentarios
Mestre em Materiais Dentários

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

Orientadores: Luiz Andre Freire Pimenta, Roger William Fernandes Moreira
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste estudo in vitro foi determinar a durabilidade da interface adesiva emdentina normal (DN) ou afetada por cárie (DAC) promovida por um sistema adesivo simplificado convencional (AdperScotchbond1/ SB)e dois sistemas autocondicionantes de dois passos(Clearfil Protect Bond / PBe AdheSE/ AD), após24 horas(24h)ou 6 meses(6me)de imersão em água.Para o teste de microtração,90 molares humanos cariados foram selecionados. A superfície dentinária foi exposta através de seccionamento com disco duplo diamantado e polimento com lixas de carbeto de silício, deixando uma área central de DAC. Osdentes foram aleatoriamente divididos em 3 grupos para que recebessem a aplicação de um dos 3 sistemas adesivos, de acordo com a recomendação dos fabricantes.Blocos de compósito Tetric Ceram com altura de 4 mm foram incrementalmente confeccionados,e após 24 h de armazenagem em água destilada a 37 oC, os dentes foram seriadamente seccionados em fatias de 1,0mm de espessura paralelas ao longo eixo dental.Em seguida,dispositivos em forma de ampulheta foram confeccionados com pontas diamantadas de granulação fina em alta rotação,com área adesiva final de aproximadamente1,0 mm2, que continham DN ou DAC. Os espécimes foram armazenados em água destilada por 24h ou 6me. Decorrido este período, os espécimes foram fixados individualmente em um dispositivo de microtração (Bencor-T),acoplado em máquina de ensaio universal (Instron), para teste à 0,5 mm/min.Após o teste, a porção dentinária dos espécimes fraturados foi avaliada em um microdurômetro do tipo Knoope também observadas em microscópio eletrônico de varredura(MEV). As médias de resistência de união foram submetidos aos testes de análise de variância (ANOVA 3 fatores),StudentNewmanKeulse t de Student(p < 0,05). Cinqüenta e quatro molares cariados adicionais foram preparados da mesma maneira supradescrita. Após 24 h de armazenagem em água destilada a 37 oC,os dentes foram seccionados em fatiasde 1,0mm de espessura paralelas ao longo eixo dental. As atias foram também armazenadas em água destilada por24h ou'6me. Os espécimes de nanoinfiltração foram imersos em solução e nitrato de prata amoniacal por 24 h, lavados abundantemente imerso sem solução foto reveladora por 8 h, sobre luz fluorescente. Após o tempo de armazenagem, fatias foram recobertas com carbono para observação em MEV. Já os espécimes de tricrômico de Masson foram manualmente polidos até que apresentassem espessura média de 3 - 5 µm, paraquefos sem corado sde acordo com as indicações da técnica histológica e visualizados em microscópio óptico. Os valores médios de microtração(MPa),foram:DN/SB/24h=42,63; DN/PB/24h= 39,18; DN/AD/24h= 28,19; DN/SB/6me= 38,43; DN/PB/6me= 39,49;DN/AD/6me=27,90;DAC/SB/24h=34,49;DAC/PB/24h=28,68;DAC/AD/24h=24,20;DAC/SB/6me= 27,76;DAC/PB/6me=24,48;DAC/AD/6me=17,24.Tantoem DNquantoem DAC,após 24h ou 6me de imersão,os sistemas SB e PB apresentaram os maiores valores de resistência de união. De uma maneira geral, maiores valores de união foram obtido sem DN, comparado à DAC.Os sistemas adesivos autocondicionantes apresentaram maior estabilidade após 6 me de armazenamento
Abstract: The purpose of this study was to investigate the durability of resin-dentin bonds to sound (SD) and caries-affected dentin(CAD)using an total-etch(Adper Scotchbon1d/ SB)or two self-etch bonding systems(Clearfil Protect Bond/ PBandAdheSE/ AD)bonding agents,after24 hours(24h)or 6 months(6mt)of storage in water.For the microtensile bond strength (Thepurposeof thisstudywasto investigatethedurabilityof resin-dentinbondstosound(SD)and caries-affected dentin(CAD)using an total-etch(AdperScotchbon1d/ SB)or two self-etch bonding systems(ClearfilProtectBond/ PBandAdheSE/ AD)bonding agents,after24hours(24h)or 6 months(6mt)of storage in water.For the microtensile bond strength(jJTBSe) valuation 90 extracted carious human molars were ground flat oclusally with wets and(SiC)papers,leaving a central region of CAD dentin surrounded by ND.The teeth were randomly assigned into three groups,according to he bonding system used. All bonding systems were applied according to manufactures instructions. Resin composite (TetricCeram) build-ups were made incrementally. After storage in distilled water at 37°C for 24 h, teeth were erially sectioned into1.0mms labs,and trimmed to yield a 1.0mm2 bonded area that contained either NDor CAD.Experimental hlourglas specimens were stored in water for 6 mt. Specimens that had been store din water for 24 hwere use das controls.Specimens were individually attached to a microtensile device(Bencor-T) which was coupled to an Instron machine and tested at a crosshead speed of 0.5 mm/min.The dentin surfaces of the fractured specimens were evaluated using Knoop microhardness test and observed by scanning electron microscopy( SEM).Data were analyzed by ANOVA,Student Newman Keulsandt Student multiple comparison tests (p < 0.05). Additional 54 extracted carious human molars were prepared for nanoleakage and Masson'strichrom evaluation as described above. After storage in distilled water at 37°Cfor24h, teeth were serially sectioned into1.0mm slabs that contained NDor CAD.Slabs were store dinwater for 24 h or 6 mt.The specimens for nanoleakage were immersed in ammoniacal silver nitrate for 24 h, rinsed thoroughly and placed in photo developing solution for 8 h under fluorescent light. Slabs weres putter-coated with carbon and observed under SEM.Trichrome specimens were manually polished to 3 - 5 µm thin sections of the adhesive/denti interface and stained with the histologica dyes.Stained thin sections from each prepared tooth were imaged with optical microscopy. The µTBS mean values obtained(MPa)were:ND/SB/24h4=2.63;ND/PB/24h= 39.18; ND/AD/24h=28.19; ND/SB/6mt=38.43; ND/PB/6mt=39.49; ND/AD/6mt=27.90; CAD/SB/24h3=4.49;CAD/PB/24h2=8.68;CAD/AD/24h2=4.20;CAD/SB/6m2t=7.76;CAD/PB/6mt= 24.48;CAD/AD/6mt= 17.24.SBandPB presented the higher µTBS values,irrespective of dentin type.Regarding bond strengths obtained with all bonding systems evaluated, it could be always observed higher mean values for ND.Self-etching bonding agents presented a higher stability after 6 mt water immersion
Doutorado
Dentística
Doutor em Clínica Odontológica

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Objective: The objectives of this study were 1) to evaluate the effect of enamel deproteinization on the shear bond strength(SBS) of orthodontic brackets bonded with a resin modified glass-ionomer (RMGI) adhesive and a composite resin, 2) to determine the mode of bond failure according to the adhesive remnant index (ARI) and 3) to evaluate the effect of these adhesives in the prevention of white spot lesions (WSLs). Background: WSLs are a concern for orthodontic patients. RMGI orthodontic adhesives are capable of absorbing fluoride from the oral environment and releasing it continuously over time, however, they are not frequently used as they exhibit low SBS. Techniques such as non-invasive enamel deproteinization with 5.25% sodium hypochlorite prior to acid etching rid the surface of organic components and have the potential to enhance the etching pattern. Methods: Eighty-eight extracted bovine incisors were randomly divided into two groups. 48 incisors in group (A) underwent SBS testing, through debonding of brackets with the Universal Testing Machine and subsequent measurement of the ARI. 40 incisors in group (B) underwent demineralization testing by measuring the depth of WSLs formed after exposure to an acidic challenge for 96 hours. In groups A and B, the teeth were divided to have brackets bonded with GC Fuji ORTHO™ LC adhesive or Transbond™ XT adhesive and a self-etching primer. Each adhesive group had an experimental group receiving the intervention of enamel deproteinization prior to etching and bonding and a control group. Results: The highest mean SBS was observed in the Transbond™ XT control group (12.48 ± 6.23 MPa) and the lowest mean SBS was observed in the Fuji ORTHO™ experimental group (5.49 ± 2.97 MPa). ANOVA and Post-Hoc Tukey tests revealed statistically significant differences (p<0.05) in the SBS of both Fuji ORTHO™ groups compared to the Transbond™ XT control group. A significantly greater percentage of Transbond™ XT control teeth had an ARI score of 0 and a greater percentage of Fuji ORTHO™ experimental teeth had an ARI score of 3. The Transbond™ XT experimental group had the largest average demineralization lesions (62.97 ± 10.95 micrometers). The smallest lesion depths were found in the Fuji ORTHO™ groups, with an average of 7.74 micrometers in the experimental group and 6.57 micrometers in the control group. ANOVA and Post-Hoc Tukey tests revealed significant differences (p<0.001) in the depth of white spot lesions when comparing both composite resin groups to each other, and when each glass ionomer group was compared to each composite resin group. Conclusions: Enamel deproteinization did not increase the SBS of orthodontic brackets bonded with either Fuji ORTHO™ adhesive or Transbond™ XT adhesive. However, according to the ARI, more bond failures occurred at the bracket-adhesive interface in the Fuji ORTHO™ experimental group. Also, both Fuji ORTHO™ adhesive groups showed greater protection against enamel demineralization, when compared to the Transbond™ XT adhesive groups.

Orientador: Flavio Henrique Baggio Aguiar
Dissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste trabalho foi investigar, in vitro, o efeito da aplicação de uma pasta contendo fosfopeptídeo de caseína - fosfato de cálcio amorfo (CPP-ACP) (MI Paste - MI) previamente ao protocolo adesivo na resistência da união de um selante resinoso de fóssulas e fissuras ao esmalte dental humano. Foram utilizados 98 espécimes de esmalte proximal de terceiros molares totalmente erupcionados, divididos em 14 grupos experimentais (n=7): G1/G8- condicionamento ácido (CA) (Scotchbond Etchant), sem a aplicação de sistema adesivo; G2/G9- CA + resina hidrófoba de um sistema adesivo convencional de três passos (Scotchbond Multipurpose Plus); G3/G10- CA + sistema adesivo convencional de dois passos (Single Bond 2); G4/G11 - CA + sistema adesivo autocondicionante de passo único (Clearfil S3 Bond); G5/G12- CA + sistema adesivo autocondicionante de dois passos (Clearfil SE Bond); G6/G13- sistema adesivo autocondicionante de dois passos; G7/G14- adesivo autocondicionante de passo único. MI foi aplicada previamente ao protocolo adesivo apenas nos grupos de G1 a G7. Após selamento das superfícies (FluroShield), foram confeccionados blocos retangulares (palitos) (~0,7mm2 de área seccional) para o ensaio de microtração. O teste foi efetuado imediatamente após confecção das amostras por meio da Máquina de Ensaio Universal, na velocidade de 0,5 mm/min. Após, o padrão de fratura foi analisado por meio de Microscopia Eletrônica de Varredura (MEV). Os valores de resistência da união foram analisados por meio de ANOVA dois fatores com parcela subdividida. A aplicação da pasta contendo CPP-ACP previamente aos sistemas adesivos convencionais e àqueles autocondicionantes sem condicionamento ácido prévio aumentou os valores de resistência da união. Houve predomínio de fraturas mistas nos grupos que receberam MI Paste, ao passo que, naqueles em que não se aplicou MI Paste a maior prevalência foi de fraturas adesivas. O contato do esmalte com CPP-ACP anteriormente à aplicação dos sistemas adesivos é um método eficaz para aumentar a resistência de união entre esmalte e selantes de fóssulas e fissuras.
Abstract: This study evaluated the effect of applying a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) containing paste (MI Paste - MI) previously to adhesive procedures on the microtensile bond strength of a pit and fissure sealant to human enamel in vitro. Ninety eight fragments were obtained from proximal surfaces of totally erupted third molars. Specimens were divided into 14 experimental groups (n=7): G1/G8- phosphoric acid conditioning (PA) (Scotchbond Etchant) and no adhesive system; G2/G9- PA + hydrophobic resin of a three step adhesive system (Scotchbond Multipurpose Plus); G3/G10- PA + etch-and-rinse two-step adhesive system (Single Bond2); G4/G11- PA + all-in-one adhesive (Clearfil S3-Bond); G5/G12- PA + two-step self-etching adhesive system (Clearfil SE-Bond); G6/G13- all-in-one adhesive; G7/G14- two-step self-etching adhesive system. MI was applied on the enamel before adhesive strategies only for groups from G1 to G7. After sealing (FluroShield), beams with approximately 0.7 mm2 of sectional area were cut for microtensile test, which was executed trough a universal test machine at a speed of 0.5 mm/min. Fractured specimens were analyzed by scanning electronic microscopy to determine failure modes. Bond strength data was statistically analyzed by two-way ANOVA with subparcels. Groups which MI was applied on the enamel followed by sealant bonding with etching-and-rinse and self-etching adhesives without additional enamel acid etching presented higher means than other which MI was not applied. Higher frequency of cohesive failures was observed for groups with MI, while adhesive fractures were more prevalent in groups without MI. Applying a CPP-ACP containing paste before adhesive systems to the enamel is an effective method to increase bond strength of the sealant tested.
Mestrado
Dentística
Mestre em Clínica Odontológica

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

The purpose of this study was to evaluate effect of final rinse of ethanol on bond strength in teeth obturated with Gutta Percha (GP)/AH Plus® or Resilon/Epiphany®SE™. Thirty-two extracted human anterior teeth were shaped to size 30, 0.06 taper and subjected to an identical irrigation protocol. Specimens were randomly divided into eight groups according to final irrigating solution (saline, 70%, 95%, 100% ethanol) and obturation material. Two millimeter thick slices were obtained by sectioning each obturated root. Bond strength was determined using micropush-out assay. Data was analyzed using Student’s t-test. Obturation with GP/AH Plus® formed a statistically significant stronger bond than Resilon/Epiphany®SE™. A final rinse with ethanol (irrespective of ethanol concentration) did not enhance push-out bond strength with GP/AH Plus®. Push-out bond strength of Resilon/Epiphany®SE™ decreases with increased ethanol concentration with Resilon/Epiphany®SE™. Among Resilon/Epiphany®SE™ groups, 70% ethanol resulted in strongest bond strength.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The aim of this study was to evaluate the adhesive characteristics of two kinds of geopolymers (G1 and G2) among five well known cements used in Dentistry: two conventional self-cure cements zinc phosphate (FZ), glass ionomer (IV) and three resin -based cements, one of them with light cure RelyX Veneer (RV) whereas the other two are dual cements RelyX ARC (RA) and RelyX U200 (RU), which is a self-adhesive product. Before the execution of the experiments themselves, forty-five non-carious molars were selected for afterwards analysis. The teeth were sectioned along the cervical line, and the crown was split along the mesial-distal line, creating 90 halves of teeth crowns. Each one was placed inside of the lumen of a segment of a regular 25mm PVC pipe. Once that was done, self-cure acrylic resin was poured into the pipes until the full submersion of the half crowns. Each block was transversally sliced, creating specimens in the shape of 2 mm thick discs. Thereupon, conic cavities were drilled into the dentin using a diamond bur. Ten samples were used for each cement and each geopolymer was used in twenty samples. These materials were inserted into these cavities, avoiding their overfill. Randomized 24h storage under relative wetness and room temperature for the selfcure cements and one sample of each geopolymer (G1u and G2u) was set. As a matter of comparison, other ten samples of the geopolymer (G1s and G2s) were stocked in a dry room, for the same period of time, so that it could be possible to analyze its adhesion without the wetness influence. Afterwards, the push-out experiments were made in a universal testing machine. The results were made under the ANOVA and Tukey tests, which showed that the best adhesive strength were showed by G2S and followed by G1S. Among the resin cements, RV obtained the best performance. G1u and G2u showed the lowest adhesive levels, without any relevant statistical differences between them. The conclusion is that the geological cements mechanical characteristics are promising, although they re very susceptible to wetness. The rational application of geopolymers in Dentistry must face an correction of is hidrosolubility, so that its clinical usage can reach a good effectiveness.
O objetivo deste trabalho foi avaliar as características adesivas de dois tipos de geopolímero (G1 e G2) frente a cinco cimentos odontológicos de uso consagrado: dois convencionais fosfato de zinco (FZ), ionômero de vidro (IV) e três resinosos, sendo um deles fotopolimerizável Relyx Veneer® (RV) , e os demais, dual - Relyx ARC® (RA) e Relyx U200® (RU), este último, autocondicionante. Previamente à execução dos ensaios, quarenta e cinco molares hígidos foram selecionados para estudo. Os elementos dentários foram seccionados na linha cervical, e a coroa foi dividida no sentido mésio-distal, gerando noventa hemi-coroas, que foram posicionadas na luz de um cano de PVC de 25mm de diâmetro. Nesse momento, elas foram incluídas em resina acrílica auto-polimerizável. Cada artefato foi desgastado, gerando um corpo de prova em forma de disco com 2mm de espessura. Em seguida, foram feitos preparos cavitários cônicos em dentina. Para cada cimento comercial, dez amostras foram utilizadas, e para os geopolímeros, vinte. Os compostos foram inseridos nesses preparos, evitando-se o extravasamento. Arbitrou-se um tempo de estocagem de 24 horas em condições de umidade relativa em temperatura ambiente para os cimentos comerciais e uma amostra de cada geopolímero (G1u e G2u). Para efeitos comparativos, outras dez amostras de cada geopolímero (G1s e G2s) foram armazenadas em ambiente seco durante o mesmo período, de modo a se conhecer suas adesões sem influência da umidade. A partir daí, foram executados ensaios de push-out em uma máquina universal. Os resultados foram submetidos aos testes de ANOVA e Tukey, que mostraram que as melhores resistências adesivas foram apresentadas por G2s, seguida por G1s. Dentre os cimentos convencionais, RV teve o melhor desempenho. G1u e G2u mostraram os níveis de adesão mais baixos, não tendo diferenças estatísticas entre si. Conclui-se que as características mecânicas dos cimentos geológicos se mostraram promissores, apesar de bastante susceptíveis à ação da umidade. O uso odontológico mais racional dos geopolímeros deve passar pela correção de seu caráter hidrossolúvel, de modo a se alcançar uma aplicabilidade clínica mais efetiva.

Orientador: Mario Fernando de Goes
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: A proposta deste estudo foi avaliar a resistência de união ao cisalhamento de onze sistemas adesivos disponíveis comercialmente sobre a superfície do esmalte e dentina, utilizando também, microscópio eletrônico de varredura para a observação do tipo de falha ocorrida na interface dente-compósito. Foram utilizados 176 dentes humanos constituídos por grupos dos pré-molares e molares, cujas raízes foram seccionadas e as coroas dentárias remanescentes incluídas com resina acrílica ativada quimicamente em tubos de PVc. A face vestibular foi desgastada com lixas d'água de granulação número 180 e 400, respectivamente, até conseguir uma área plana de 5 mm de diâmetro na superfície do esmalte ou dentina. Após a preparação das superfícies dentárias, uma fita adesiva circular com um orifício central de 4 mm de diâmetro foi aderida sobre a superfície do esmalte ou dentina, com a finalidade de delimitar a área onde se efetuaria a união adesivo-material restaurador. A área delimitada para a união (esmalte ou dentina) foi tratada com um dos seguintes sistemas adesivos: Scotchbond Multi-Purpose e Scotchbond 2 (3M Dental), Optibond e XR Bonding (Kerr), All Bond 2 (Bisco), Denthesive II (Kulzer), Syntac (Vivadent), Multi Bond Alpha (DFL), Heliobond (Vivadent), Pro-bond e Prisma Universal Bond 3 (Caulk / Dentsply). Durante a utilização de cada sistema adesivo, as instruções dos respectivos fabricantes foram rigorosamente seguidas. O compósito restaurador utilizado foi aquele indicado por cada fabricante para cada sistema adesivo, excessão feita aos materiais Multi Bond Alpha e All Bond 2, que utilizaram o compósito restaurador Z 100 (3M Dental). Em seguida, cada compósito restaurador, foi inserido com o auxílio de uma matriz de aço inoxidável (4 mm de diâmetro or 5 mm de altura), em três camadas, cada uma polimerizada durante 40 segundos. Os corpos de prova foram armazenados a 37 'GRAUS'C e 100% de umidade relativa durante 24 horas e submetidos ao ensaio de resistência ao cisalhamento em máquina de ensaio universal Otto Wolpert Werke, a uma velocidade de 6 mm/min. Após a fratura, as superfícies das amostras em esmalte ou dentina de cada grupo de material, foram revestidas com ouro-paládio sob alto vácuo para observação em microscopia eletrônica de varredura. A análise de variância e o teste de Tukey, ao nível de 5% de significância, mostraram que a média de resistência ao cisalhamento na superfície do esmalte para o produto Optibond (14,21 MPa) foi significativamente superior do que os demais produtos testados. Em seguida, vieram os produtos Scotchbond Multi-Purpose (10,49 MPa), All Bond 2 (10,44 MPa) e Syntac (10,42 MPa) que foram estatisticamente iguais entre si, 8 inferiores ao produto Optibond e superiores aos demais produtos. Logo após, vieram os produtos Pró-Bond (8,11 MPa), Multi Bond Alpha (8,00 MPa), Denthesive II (7,89 MPa) e XR Bonding (7,37 MPa) que foram estatisticamente iguais entre si e superiores aos produtos Scotchbond 2 (6,25 MPa), Prisma Universal Bond 3 (6,23 MPa) e Heliobond (5,12 MPa) que foram iguais entre si. Os produtos XR Bonding, Scotchbond 2 e Prisma Universal Bond 3, foram estatisticamente iguais entre si. Em dentina, a análise de variância e o teste de Tukey, ao nível de 5% de significância, mostraram que os produtos Optibond (6,17 MPa), Scotchbond Multi-Purpose (6,06 MPa) e All Bond 2 (5,39 MPa) foram estatisticamente iguais entre si e superiores aos demais produtos, excessão para o produto All Bond 2 em relação aos produtos Denthesive II, Syntac e Pro-Bond, cujas médias foram estatisticamente iguais entre si. Os produtos Denthesive 11 (4,30 MPa), Syntac (4,29 MPa), Pro-Bond (4,04 MPa), Prisma Universal Bond 3 (3,59 MPa), XR Bonding (3,44 MPa), Scotchbond 2 (3,39 MPa) e Multi Bond Alpha (3,38 MPa) obtiveram médias estatisticamente semelhantes entre si e superiores ao material Heliobond (1,40 MPa), que foi inferior a todos os produtos testados. As fotomicrografias das regiões de fratura para as amostras em esmalte, mostraram que a falha mais comumente observada em todos os grupos, foi a falha do tipo coesiva no adesivo. Já nas amostras em dentina, pudemos observar falhas do tipo coesivano adesivo para os produtos de quarta geração, e do tipo adesiva na interface dentinacompósito para os produtos de terceira geração e para o material Heliobond, de primeira geração
Abstract: The purpose of this study was to evaluate the shear bond strength from eleven adhesive systems commercially available on enamel and dentin surface, also using, scanning electron microscopy to observe the ailure type occured in tooth/composite interface. One hundred seventy-six extracted human permanent molar and premolar teeth were mounted in phenolic rings with cold-cure acrylic resin and the facial surfaces were ground wet in a polishing block on a polishing machine on 180 - followed by 400 - grit silicon carbide paper. Adhesive tape with a circular hole, 4 mm in diameter, was placed on the ground enamel and dentin surfaces to delineate the bonding areas. The delianeated area was treated with one of following adhesive systems: Scotchbond Multi-Purpose and Scotchbond 2 (3M Dental), Optibond and XR Bonding (Kerr), All Bond 2 (Bisco), Denthesive II (Kulzer), Syntac (Vivadent), Multi Bond Alpha (DFL), Heliobond (Vivadent), Pro-bond and Prisma Universal Bond 3 (Caulk / Dentsply). During the utilisation of each adhesive system, the manufacturer's instructions were followed. The composite resin used was that indicated for each manufacturer to each adhesive system, exception to Multi Bond Alpha and All Bond 2 materials, that used the Z-100 composite resin (3M). Next, each composite resin, was inserted in a split metal mold in three increments. Each increment was compressed firmly and exposed to visible ligth for 40 seconds. The specimens were stored in distilled water at 37 'DEGREE' C for 24 hours and the shear bond strengths were determined by using an Otto Wolpert Werke universal testing machine operated at a cross-head speed of 6 mm/min. After the failure, representative specimens from each group were examined by scanning electron microscopy. In enamel, ANOVA and Tukey's test, at 5% significance level, showed that the product Optibond (14,21 MPa) was superior statistically in relation to other products. Next, came the Scotchbond Multi-Purpose (10,49 MPa), All Bond 2 (10,44 MPa) and Syntac (10,42 MPa) that were statistically equal between themselves and superior in relation to the other products. After, came the products Pro-Bond (8,11 MPa), Multi Bond Alpha (8,00 MPa), Denthesive II (7,89 MPa) and XR Bonding (7,37 MPa) that were statistically equal between themselves and superior to the products Scotchbond 2 (6,25 MPa), Prisma Universal Bond 3 (6,23 MPa) and Heliobond (5,12 MPa), that were equal between. In dentin, ANOVA and Tukey's test, at 5% significance level, showed that the MPa) were statistically equal between themselves and superior in relation to the other products. Next, carne the products Denthesive II (4,30 MPa), Syntac (4,29 MPa), Pro-Bond (4,04 MPa), Prisma Universal Bond 3 (3,59 MPa), XR Bonding (3,44 MPa), Scotchbond 2 products Optibond (6,17 MPa), Scotchbond Multi-Purpose (6,06 MPa), All Bond 2 (5,39 themselves. The products Xr Bonding, Scotchbond 2 and Prisma Universal Bond 3, were statistically equal between themselves. "third and first generation" products type was the coesive one in adhesive. Now, in dentin samples, coesive failure occured in adhesive to "fourth generation" producd, and adhesive failure at dentin/composite interface to Electronmicrographs of enamel surfaces showed that the most common failure products. The products All Bond 2, Denthesive II, Syntac and Pro-Bond, were statistically equal between themselves (3,39 MPa) and Multi Bond Alpha (3,38 MPa), that were statistically equal between themselves and superior to the product Heliobond (1,40 MPa), that was inferior to all products. The products All Bond 2, Denthesive II, Syntac and Pro-Bond, were statistically equal between themselves. Electronmicrographs of enamel surfaces showed that the most common failure type was the coesive one in adhesive. Now, in dentin samples, coesive failure occured in adhesive to "fourth generation" producd, and adhesive failure at dentin/composite interface to "third and first generation" products
Mestrado
Materiais Dentarios
Mestre em Odontologia

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Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia)
IPEN/D-MPLO
Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry. Objectives: To determine the amount of initial fluoride release from four orthodontic bonding systems over a period of four weeks, and then to subject these materials to an external source of fluoride for recharge in order to measure the amount of fluoride re-release over another four-week interval. Additionally the surface morphology of these materials was analyzed under the scanning electron microscope in order to identify microscopic changes in the materials that may have occurred during the experiment. Methods: Four orthodontic adhesives: Fuji Ortho LC (GC America, Alsip, IL), Transbond XT (3M Unitek, Monrovia, CA), Illuminate Light Cure (Ortho Organizers, Carlsbad, CA), and Opal Seal with Opal Bond MV (Ultradent, South Jordan, UT), n=120 (30/material) were tested for fluoride release at 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. Samples (10/subgroup/material) were then recharged with an external source of fluoride (toothpaste, foam, or varnish), and retested for fluoride re-release at 1 hour, 24 hours, 3 days, 1 week, 2 weeks, 3 weeks and 4 weeks. The scanning electron microscope was utilized in order to assess each material's surface morphology before testing and after completion of the experiment (n=16). Descriptive statistics, means and standard deviations were calculated for all four materials and their subgroups at each time interval. A mixed model two-way ANOVA was run, using a level of significance of 0.05. Bonferroni multiple comparison tests were conducted using if groups were found to be statistically significantly different. To determine significant differences between fluoride release and re-release for each recharge subgroup within each material group, paired t-tests were performed for the time intervals of 24 hours, 2 weeks, and 4 weeks. For the paired t-tests, the level of significance used was 0.02 to allow for Bonferroni correction. Results: During the initial 24 hours the fluoride measurements (in mg/L or ppm) were as follows: Fuji 9.78±0.65, Illuminate 7.83±1.49, Opal 0.05±0.02, and Transbond 0.01±0.0. At the initial four weeks time point, the readings were as follows: Fuji 6.68±0.79, Illuminate 3.82±1.84, Opal 0.06±0.01, and Transbond 0.01±0.01. The greatest fluoride release came from the varnish subgroups from each of the materials at 2 weeks post re-charge: Fuji 9.16±1.53, Illuminate 7.5±3.1 (tied with foam subgroup 7.5±4.4), Opal 5.3±2.45, and Transbond 3.75±1.67. The greatest fluoride measurement for each material at the final week post-recharge was: Fuji varnish subgroup 8.3±3.58, Illuminate foam subgroup 6.5±3.5, Opal varnish subgroup 2.50±1.1, and Transbond varnish subgroup 1.72±1.82. SEM results showed an observable difference between the materials pre-experiment and post-experiment at a magnification of 50X and 500X. The Fuji foam and paste subgroups displayed surface crackling patterns at both magnifications when compared to the control and varnish samples. The Illuminate control, foam, and paste specimens all had a roughened grainy appearance, while the varnish specimen seemed to be smoothed over by the varnish material. The Transbond samples appeared to have observable differences in surface morphology at 50X, but not at 500X. The Opal paste and foam specimens appeared to have a smoother surface than both the control and the varnish samples. Conclusions: There were significant differences in release and re-release of fluoride among all four adhesives at different time intervals over a period of eight weeks. Significant increase in fluoride re-release was seen for all three of the recharge subgroups for both Opal and Transbond at each time interval. A significant increase in fluoride re-release for the Illuminate group was mainly observed at the end of second and fourth week. Though no significant increase in fluoride re-release was observed, Fuji released highest amount of fluoride during release and re-release, at all different time intervals. Fluoride varnish was the superior recharge material, as it provided the greatest fluoride measurements, followed by foam and toothpaste. There were observable changes in the surface morphology of the materials pre-experiment and post-experiment at a magnification of 50X and 500X, which may have an affect on the fluoride releasing capabilities of the materials.