Made available in DSpace on 2014-08-20T14:30:09Z (GMT). No. of bitstreams: 1 Dissertacao_joziane_luzia_dias_dame.pdf: 564053 bytes, checksum: dd7e96465f7bec29457bc90946463293 (MD5) Previous issue date: 2006-06-23 / Contamination while restoration procedures are carried out is mentioned in literature as a very frequent event, besides that, there are only a few papers which value this contamination influence in adhesion and possible decontamination methods to be carried out under such an occurrence. So, the aim of this study was to evaluate the influence of decontamination protocols upon dye leakage and push-out bond strength of a dentin adhesive system. It was used a hundred thirty five bovine incisors, which had their labial surface ground to obtain a flat dentine surface where standardized cylindrical cavities were made and they were divided in three groups: A) control without contamination (n = 15); B) contamination prior to the adhesive light activation (Adper Single Bond 2 3M ESPE) (n = 60) and C) contamination after the light activation (n = 60). After the contamination the cavities were divided (n = 15) according to the protocol used: 1) absorbent paper; 2) water; 3) conditioning with phosphoric acid or 4) sodium hypochlorite at 10%. The cavities were restored with the composite (Filtek Z250 3M ESPE), applied to only one increment. After 24 hours the restorations were polished and the specimens were subjected to thermal cycling (500 cycles/5o C a 55oC/30s). The exposure of the stained margins was done through the use of 2% methylene blue dye (pH = 7.0) and digital measurement of the restorations. The specimens cavity floor was ground, exposing the restoration, and they were submitted to the extrusion test (push out) in a universal testing machine. To statistics analysis it was used ANOVA according to two criteria (moment and protocol) and Tukey s test. In the marginal sealing evaluation there was significant statistics in the moment factor (p<0.001) and also in the interaction moment x protocol (p<0.008). The percentage average of stained margins found after light activation was statistically higher than the ones found prior to the light activation (p<0.001). In group B the conditioning protocol showed a percentage average of stained margins statistically higher than the water group (p<0.003), and the paper and hypochlorite groups demonstrated intermediate values. Comparing to group C protocols, it was not detected significant differences. Relating to the extrusion resistance, only the moment factor was statistically significant (p<0.001), while group B values were statistically higher (p<0.05) than the group C ones (5.32+3.03 and 3.4+1.92 MPa respectively). All protocols demonstrated resistance values similar to the control values. Higher resistance values were related to lower values of stained margins. It was concluded that blood contamination after light activation of the adhesive system had an adverse effect in the sealing ability of composite restorations and the different decontamination protocols generally produced similar results / A contaminação durante a realização de procedimentos restauradores é citada na literatura como um evento muito freqüente, apesar disso, poucos são os trabalhos que avaliam a influência desta contaminação na adesão e possíveis métodos de descontaminação a serem realizados frente a sua ocorrência. Assim, este trabalho teve como objetivo avaliar a influência dos métodos de descontaminação no selamento marginal e na resistência à extrusão de um sistema adesivo dentinário. Foram utilizados 135 incisivos bovinos, que tiveram a face vestibular desgastada expondo-se dentina, onde foram confeccionadas cavidades circulares padronizadas. Estas foram distribuídas em três grupos: A) controle, sem contaminação (n = 15); B) contaminação previamente à fotoativação do adesivo (Adper Single Bond 2 - 3M ESPE) (n = 60) e C) contaminação após a fotoativação (n = 60). Após a contaminação as cavidades foram divididas (n = 15) de acordo com o método utilizado: 1) papel absorvente; 2) água; 3) condicionamento com ácido fosfórico ou 4) hipoclorito de sódio a 10%. As cavidades foram restauradas com o compósito (Filtek Z250 - 3M ESPE), aplicando-se um único incremento. Após 24h as restaurações foram polidas e os espécimes submetidos à ciclagem térmica (500 ciclos/5°C a 55°C/30s). O selamento marginal foi avaliado utilizando-se o corante azul de metileno a 2% (pH = 7,0) seguido da digitalização das restaurações. Os espécimes foram desgastados pela face lingual expondo a restauração, e submetidos ao ensaio de extrusão (push out) em uma máquina de ensaios mecânicos. Para a análise estatística foram utilizados ANOVA segundo dois critérios (momento x método) e Teste de Tukey. Na avaliação do selamento marginal houve significância estatística para o fator momento (p<0,001) e também para interação momento X método (p=0,008). O nível médio de margens coradas encontradas após a fotoativação foi estatisticamente superior ao encontrado previamente a fotoativação (p<0,001). Dentro do Grupo B o método condicionamento demonstrou uma média de margens coradas estatisticamente superior ao grupo água (p<0,003), e os grupos papel e hipoclorito demonstraram valores intermediários. Para as comparações entre métodos dentro do Grupo C não foram detectadas diferenças significativas. Em relação à resistência à extrusão, apenas o fator momento demonstrou ser estatisticamente significante (p<0,001), sendo os valores do Grupo B estatisticamente superiores (p<0,05) aos do Grupo C (5,32±3,03 e 3,4±1,92 MPa respectivamente). Todos os métodos demonstraram valores de resistência similares ao controle. Maiores valores de resistência foram relacionados a menores valores de margens coradas. Concluiu-se que a contaminação com sangue após a fotoativação do sistema adesivo teve um efeito adverso na capacidade de selamento de restaurações de compósito e os diferentes métodos de descontaminação geralmente produziram resultados similares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate the effect of repolishing after bleaching on color stability and roughness of two composite resins aged in high staining beverage. Sixty-one disc-shaped specimens (8 mm diameter x 2 mm thickness) of each composite resin were fabricated (microhybrid vs. nanoparticle), then divided according to treatment: bleached or non-bleached. After bleaching phase, groups were subdivided according to surface treatment, repolished or unrepolished, using extrafine sandpaper discs and felt with diamond paste. A new subdivision was performed according to aging conditions: immersion in red wine 15 min/day or in artificial saliva 24 h/day during 30 days. Color (CIE L*a*b* system) and roughness (Ra) were assessed at baseline (P0), after bleaching procedures (P1), after surface treatment (P2) and after aging (P3). Color change (ΔE00) was calculated with CIEDE2000 formula. One specimen per group was removed from each study phase, in order to be analyzed in Scanning Electron Microscope (SEM). Statistical analysis was performed using repeated measures ANOVA and Tukey s test as post-hoc (significance level was set at 5%). Bleached repolished groups presented lower color alteration than the bleached unrepolished groups of both composite resins when aged in red wine. Repolishing (P1 vs. P2) promoted a decrease in roughness values of almost all groups. Nanoparticle resin presented greater ΔE00 values than microhybrid one when aged in red wine. SEM images reveled more porosities in bleached unrepolished groups. Therefore, repolishing immediately after bleaching improves color stability of composite resins when exposed to staining agents, and it is capable to improve smoothness. / Este trabalho avaliou o efeito do repolimento após clareamento na estabilidade de cor e na rugosidade de duas resinas compostas ao serem expostas à solução de alto potencial pigmentante. Foram confeccionados 61 corpos de prova em forma de disco (8 mm diâmetro x 2 mm espessura) de cada resina (microhíbrida vs. nanoparticulada), que foram divididos conforme tratamento recebido: clareados ou não clareados. Após, os grupos foram subdivididos de acordo com o tratamento de superfície, com repolimento ou sem repolimento, usando discos de lixa na granulação extrafina e feltro com pasta diamantada extrafina. Nova subdivisão foi realizada baseada no meio de armazenamento: 15 min/dia em vinho tinto ou 24 h/dia em saliva artificial durante 30 dias. Sucessivas leituras de cor e rugosidade (Ra) foram efetuadas após 24 h da confecção dos cps (P0), após tratamento clareador (P1), após tratamento de superfície (P2) e após imersão (P3). A alteração de cor (ΔE00) foi calculada pela equação CIEDE2000. Em cada fase do estudo, um corpo de prova de cada grupo foi removido e analisado por microscopia eletrônica de varredura (MEV). A análise estatística foi realizada pelo Teste de Análise de Variância para medidas repetidas seguido do Teste de Tukey como post-hoc (nível de significância de 5%). Os grupos clareados repolidos apresentaram menor alteração de cor que os grupos clareados não repolidos das duas resinas compostas quando imersas em vinho tinto. O repolimento (P2 vs. P1) promoveu diminuição dos valores de rugosidade de quase todos os grupos. A resina nanoparticulada apresentou valores maiores de alteração de cor que a resina microhíbrida nos grupos imersos em vinho. As imagens de MEV mostraram maior número de porosidades nos grupos clareados não repolidos. Portanto, o repolimento imediatamente após o clareamento aumenta a estabilidade de cor de resinas compostas quando há contato com agentes corantes, e também pode diminuir a rugosidade desses materiais.

Orientador: Flávio Henrique Baggio Aguiar / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T02:52:29Z (GMT). No. of bitstreams: 1 Theobaldo_JessicaDias_M.pdf: 1963787 bytes, checksum: cb1d935e6d8c39551ed0eb14ebf3065f (MD5) Previous issue date: 2015 / Resumo: Este estudo avaliou o efeito da fumaça do cigarro nas propriedades físico-químicas da estrutura dental e na resistência de união à resina composta utilizando diferentes sistemas adesivos, em dois estudos. O objetivo do Estudo 1 foi avaliar a influência da exposição à fumaça (20 cigarros/dia, durante 5 dias) e da ciclagem de pH (8 dias) na composição química e na dureza superficial e sub-superficial do esmalte dental. Foram utilizados 40 fragmentos dentais bovinos (esmalte e dentina), divididos em 4 grupos (n=10): Controle¿ sem nenhum tratamento; CS- exposição à fumaça de cigarro; PC- ciclagem de pH; e CS-PC¿ exposição à fumaça e ciclagem de pH. Após os tratamentos, as amostras foram submetidas à análise de Microfluorescência por Rx, Fluorescência por Rx e análise de microdureza superficial e sub-superficial. Os dados foram submetidos à análise estatística ANOVA e teste de Tukey, além do Teste de Fisher para análise de Microfluorescência por Rx (?<0,05). Na microfluorescência, observou-se uma maior quantidade dos elementos Cádmio e Níquel, e traços de Chumbo e Arsênio para CS e CS-PC. A microdureza superficial e sub-superficial de esmalte foi maior para o grupo CS diferindo estatisticamente do grupo controle. Para os grupos submetidos à ciclagem de pH, houve menor microdureza, sem diferença entre amostras expostas ou não à fumaça de cigarro, e estas diferiram dos grupos Controle e CS. No Estudo 2, analisou-se resistência adesiva de restaurações realizadas com diferentes sistemas adesivos, através do teste de microcisalhamento em esmalte e dentina, sendo o esmalte submetido ou não à exposição à fumaça de cigarro. Utilizou-se 80 fragmentos dentais bovinos, divididos em 8 grupos (n=10), de acordo com o tipo de adesivo [SBMP- Scotchbond¿ Multi-uso (3M ESPE), SB- Single Bond 2 (3M ESPE); CSEB- Clearfil SE Bond (Kuraray) e SBU- Single Bond Universal (3M ESPE)] e a exposição à fumaça (sem exposição; exposição), previamente à realização da restauração com resina [Filtek Z350XT flow (3M ESPE)]. Após o microcisalhamento em esmalte, o mesmo foi desgastado até exposição da dentina, e o procedimento restaurador foi repetido. Para esmalte, não houve diferença em relação à exposição ou não à fumaça de cigarro (p=0,1397), somente entre os sistemas adesivos (p<0,001). CSEB e SBU apresentaram os maiores valores de resistência de união, mas ambos diferiram do SB, que apresentou os menores valores. SBMP apresentou valores intermediários. Para dentina, os grupos submetidos à fumaça de cigarro obtiveram valores de resistência de união menores que os não expostos (p<0,001). Para os grupos não expostos à fumaça de cigarro, CSEB apresentou os maiores valores diferindo do SBMP. SB e SBU apresentaram valores intermediários. Para os grupos expostos à fumaça de cigarro, SBU apresentou os maiores valores diferindo de SB e CSEB. SBMP apresentou valores intermediários. Conclui-se que a exposição à fumaça de cigarro permitiu a incorporação de metais pesados na estrutura dental, aumentou a microdureza do esmalte sem promover efeito no processo de desenvolvimento da cárie in vitro, e a fumaça de cigarro diminui a resistência de união adesiva para alguns sistemas adesivos em dentina, mas não em esmalte / Abstract: This study evaluated the effect of cigarette smoke on physico-chemical properties of enamel and dentin and bond strength to resin composite using different adhesive systems. For this, it was divided into two studies. Study 1 evaluated the influence of exposure to smoke (20 cigarettes per day for 5 days) and pH cycling (8 day cycle) in the chemical composition and surface and cross-sectional microhardness of dental substrate. 40 bovine dental fragments (enamel and dentin) were allocated into 4 groups (n=10): Control- without any treatment, CS- exposure to cigarette smoke, PC- pH cycling and CS-PC- exposure to smoke and pH cycling. After that, samples are subjected to X¿Ray Microfluorescence, X¿Ray Fluorescence and surface and cross-sectional microhardness. It was possible to observe a high amount of Cd and Pb and a low amount of Ni and As in dental structure. The enamel surface and cross-section microhardness means of CS was statistically higher than the control group. The samples exposed to pH cycling (PC and CS-PC) showed lower surface microhardness means than the groups not exposed to the cycling (CS and Control), did not differ them. Study 2 evaluated the bond strength of composite resin restorations in teeth submitted or not to exposure to cigarette smoke. The bond strength was be evaluated in both enamel and dentin tissue. A total of 80 bovine dental fragments will be used. The fragments are divided into 8 groups (n=10), according to the type of adhesive (Scotchbond ¿ Multi-Purpose - 3M ESPE; Single Bond 2 - 3M ESPE; Clearfil SE Bond ¿ Kuraray; Single Bond Universal - 3M ESPE) and exposure to smoke (no exposure; exposure for 5 days, using 1 pack per day) previously to restoration with composite resin [Filtek Z250 (3M ESPE)]. After microshear enamel, it has been worn to exposed dentin and the restorative procedure was repeated. Data were statistically analyzed using ANOVA and Tukey test (p <0.05). For enamel, there was no difference in relation to exposure or not to cigarette smoke (p=0.1397), however, there were differences among the adhesive systems (p<0.001). CSEB showed higher values and did not differ from SBU, but both were statistically different from SB. The SBMP showed intermediate values while SB demonstrated lower values. For dentin, specimens subjected to cigarette smoke obtained bond strength values smaller to those not exposed to smoke (p<0.001). For the groups without exposure to cigarett smoke, CSEB showed higher values, differing from SBMP (lower values). SB and SBU showed intermediary values. For the groups with exposure to cigarett, SBU showed higher values differing from adhesives SB and CSEB that showed the lower. The adhesive SBMP showed intermediate value. It is possible to conclude that the exposure to cigarette smoke promoted heavy metal contamination both in surface and in depth, the smoke exposure increased the enamel microhardness without promoting an effect on the development of caries in vitro and the exposure of the tooth structure to cigarette smoke influence on the bonding strength of some adhesive on dentin, but not in enamel / Mestrado / Dentística / Mestra em Clínica Odontológica

Orientadores: Luís Roberto Marcondes Martins, Regina Maria Puppin Rontani / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-27T11:06:52Z (GMT). No. of bitstreams: 1 OliveiraJunior_CarlosdaCunha_D.pdf: 1940639 bytes, checksum: dd88a15626c32be08decb32f8ccbf98d (MD5) Previous issue date: 2015 / Resumo: O objetivo do estudo é avaliar in vitro o efeito da ciclagem termo mecânica na resistência de união push out e adaptação marginal em dentina. Para isso, foram confeccionados 60 blocos de dentina bovina, com dimensões 4mmX4mmX2mm e restaurados com diferentes sistemas adesivos: Single Bonde (SB - 3M), Clearfil SE Bond (CB) e Clearfil SE Protect (CP) (Kuraray). Foram feitas cavidades de 2 mm de diâmetro no centro dos blocos, que foram restaurados com compósito resinoso Z350 cor A3,5, e depois de armazenados em 100% de umidade. Foram polidos com discos Sof-lex da série laranja em sequência decrescente de abrasividade. Em seguida, 30 blocos foram aleatorizados para o grupo controle e os outros 30 foram imersos em fucsina 0,5% por 24h, em seguida, imersos em água por 4h e o excesso de fucsina removido. Foram, então, fotografados para o registro de possíveis fendas formadas. Em seguida, estes blocos foram submetidos à ciclagem mecânica (100.000 ciclos) e térmica (1.000 ciclos). Após o processo de fadiga termomecânica, os blocos foram novamente imersos em fuccina e novas imagens foram registradas. Estas foram analisadas através do software Image J, no qual se registrou o percentual de fendas antes e depois da ciclagem termomecânica pela equação: %fenda = l/lt x 100, onde l é o perímetro da fenda e lt é o perímetro da restauração total. Logo depois, os blocos foram levados ao testes de push out, onde se registrou a resistência de união dos sistemas adesivos estudados que foi comparada com o grupo controle. Os dados foram submetidos ao teste estatístico não paramétrico Kruskal-Wallis e Dunn, por meio do teste de Mann-Whitney para os valores de resitência push out e a análise de percentagem de fendas antes e depois da ciclagem termomecânica se deu pela ANOVA 2 fatores. Os resultados não mostraram diferença estatisticamente significativa entre os grupos no percentual de fendas formadas antes e após a ciclagem termomecânica, mas o grupo ciclado mostrou diferença estatística com o grupo controle, o grupo CP não foi estatisticamente diferente do CB e SB, por outro lado, CB e SB foi estatisticamente diferente. Estes achados sugerem que a ciclagem termomecânica diminuiu significativamente os valores de resistência de união push-out / Abstract: The objective of study to evaluate in vitro the effect of mechanical term cycling on the bond strength push out and marginal adaptation in dentin. For this, were made 60 bovine dentin blocks with dimensions 4mmX4mmX2mm and restored with different adhesive systems: Single Bonde (SB - 3M), Clearfil SE Bond (CB) and Clearfil SE Protect (CP) (Kuraray). 2 mm diameter wells were made in the center of the blocks that have been restored with composite resin Z350 A3,5 color and then stored in 100% humidity. They were polished with Sof-Lex discs orange series in decreasing abrasiveness sequence. Then 30 blocks were randomized to the control group and others 30 were immersed in 0.5% fuchsin for 24 hours, then immersed in water for 4 hours and the fuchsin excess removed. They were photographed to record possible gaps formed. Then these blocks were submitted to mechanical (100,000 cycles) and thermal (1,000 cycles) cycling. After the process of thermomechanical fatigue, the blocks were immersed in fuchsin and new images were recorded. They were analyzed using Image J software, on which registered the percentage of gaps before and after the thermomechanical cycling by the equation: % gap = l / l x 100, where L is the perimeter of the gap and Lt is the total perimeter of the restoration. After, the blocks were taken to push out test where the registered the bond strength of adhesive systems was compared with the control group. Data were subjected to statistical nonparametric Kruskal-Wallis and Dunn, using the Mann-Whitney test for bond strenght to push out, and the analysis values of the percentage of gap before and after the thermomechanical cycling was submited for ANOVA 2way. The results showed no statistically significant difference between groups in the percentage of gap formed before and after thermomechanical cycling, but cycling group showed statistical difference with the control group, the CP group was not statistically different from the CB and SB on the other hand, CB and SB were statistically different. These findings suggest that the thermomechanical cycling decreased the bond strength values push out / Doutorado / Materiais Dentarios / Doutor em Materiais Dentários

Objetivo: Comparar in vitro la microdureza superficial de dos resinas convencionales con dos resinas Bulk Fill precalentadas. Materiales y Métodos: La muestra estuvo conformada por 112 discos de resina compuesta. Se utilizaron 2 marcas de resinas convencionales (Te-Econom Plus® y Filtek™Z350XT) y Bulk Fill (Tetric® N- Ceram Bulk Fill y Filtek™ Bulk Fill). Se formaron 2 grupos (control y precalentadas) por cada marca de resina compuesta. El grupo control se realizó de acuerdo con las indicaciones del fabricante y el grupo precalentadas se expuso a 40°C a través de la máquina AR HEAT/15 min. Se evaluó la microdureza superficial a través de un Microdurómetro Electrónico punta Vickers (carga: 0.4903 N/10 s.). Los datos fueron analizados mediante estadística descriptiva (media ± desviación estándar) y la comparación de variables, se realizó mediante las pruebas de t de Student, Wilcoxon y U de Mann Whitney. Resultados: Los valores de microdureza superficial (media±d.e.) fueron: 15.33±3.10 en la resina Te-Econom Plus®, 18.80±0.80 en la resina Tetric® N- Ceram Bulk Fill, 38.12±1.49 en la resina Filtek™Z350XT y 28.80±0.80 en la resina Filtek™ Bulk Fill. Se encontraron diferencias significativas entre las resinas Bulk Fill y sus correspondientes resinas convencionales (p<0.0001y p=0.0002). Conclusión: Al comparar in vitro la microdureza superficial de dos resinas convencionales y dos resinas Bulk Fill precalentadas a 40ºC, se demostró que las resinas tipo convencional 3M ESPE® y Bulk Fill Ivoclar Vivandent® presentaron mayor microdureza superficial. Asimismo, el precalentamiento a 40ºC aumentó la microdureza superficial de las resinas evaluadas a excepción de las resinas Filtek™ Bulk Fill. Esta técnica favorece a la dureza del material restaurador según la composición de cada resina. / Aim:  To compare in vitro the superficial microhardness of two conventional composite resins with two preheated Bulk Fill composite resins.   Materials and Methods: The sample consisted of 112 composite resin discs. Two brands of conventional composite resins (Te-Econom Plus® and Filtek™Z350XT) and Bulk Fill composite resins (Tetric® N- Ceram Bulk Fill and Filtek™ Bulk Fill) were used. Two groups (control and preheated) were made for each composite resin brand. The control group was carried out in accordance with the manufacturer’s instructions and the preheated group was exposed to 40°C heat using an AR HEAT/15min machine. The superficial microhardness was evaluated using a microhardness tester and a Vickers diamond indenter (Electronic Microdurometer - load: 0.4903 N/10 s.). The data was analyzed using descriptive statistics (mean, ±standard deviation) and the variables comparison was performed using Mann Whitney's Student, Wilcoxon, and U t-tests.   Results: The superficial microhardness values (mean ±sd.) were: 15.33±3.10 for Te-Econom Plus® and 8.80±0.80 for Tetric® N- Ceram Bulk Fill; (p<001). For Filtek™Z350XT the value was 38.12±1.49 and for Filtek™ Bulk Fill; (p<0.01) it was 28.80±0.80. The microhardness of all resins increased after preheating when compared with the control group, except for the Filtek Bulk resin.   Conclusion: Comparing in vitro the superficial microhardness of two conventional resins and two Bulk Fill type resins preheated to 40ºC, it was observed that conventional 3M ESPE® resin and Bulk Fill Ivoclar Vivandent® resin presented higher superficial microhardness. It was concluded that preheating to 40ºC increases the superficial microhardness of the composite resins evaluated, except for the Filtek™ Bulk Fill. This procedure improves the hardness of the restorative material in accordance with the composition of each composite resin. / Tesis

Indiana University-Purdue University Indianapolis (IUPUI) / The general aim of this study was to investigate the influence of the localized irradiance beam profiles from multiple light-emitting-diode (LED) light-curing units (LCUs) on the polymerization pattern within a resin-matrix composite (RMC). Irradiance beam profiles were generated from one quartz-tungsten-halogen and various single and multiple emission peak LED LCUs using a camera-based beam profiler system combined with LCU power measurements obtained using an integrating sphere/spectrometer assembly. The influence of distance on irradiance, radiant exposure (RE) and degree of conversion (DC) on the top and bottom surfaces of a RMC increment, using various LCUs, at two clinically relevant distances was investigated. Molar absorptivity of the photoinitiators present in the nano-hybrid RMC (Tetric EvoCeram bleaching shade-XL) assessed was using UV-spectrophotometry. The correlation among irradiance, RE and DC was explored. A mapping approach was used to investigate DC, microhardness and cross-link density (CLD) within 5×5×2 mm specimens at various depths; top, 0.5, 0.7, 0.9, 1.1, 1.3,1.5 mm and bottom. The localized irradiance correlation with its corresponding DC, microhardness and CLD was explored, and localized DC correlation with microhardness was assessed. The DC was measured using micro-Raman spectroscopy, and CLD was assessed by an ethanol-softening method (%KHN reduction) using an automated microhardness tester. Molar absorptivity of diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide was 20-fold higher than camphorquinone. Non-uniform LCU beam profiles caused localized polymerization discrepancies that were significant at specific depths and points within the specimens with respect to DC, microhardness and CLD, which did not follow a specific pattern regardless of the LCU or curing distance assessed. A moderate correlation was displayed among irradiance, RE and DC. The localized irradiance from the LCUs was weakly correlated with the corresponding DC, microhardness and CLD on the top surface of a RMC at both curing distances. The localized microhardness was moderately correlated with DC. In conclusion, polymerization within the RMC investigated was non-uniform and did not reflect the LCU irradiance pattern at the area assessed. Also, a mapping approach within the specimens provided a detailed polymerization pattern assessment occurring within a RMC increment. Therefore, the LCUs explored may potentially increase the risk of RMC fracture.

Indiana University-Purdue University Indianapolis (IUPUI) / Objectives: Repair of crown margins may extend the functional life of existing crowns. However, the longevity of such treatment is unknown. This study determined the survival time of crown margin repairs (CMR) with glass-ionomer (GI) and resin-modified glass-ionomer cements. Methods: We queried axiUm (Exan Group, Coquitlam, BC, Canada) database for permanent teeth that underwent CMR in the Graduate Operative Dentistry Clinic, Indiana University School of Dentistry (IUSD), Indianapolis, Ind., USA, from January 1, 2006 through January 1, 2018. Since there is no CDT code for the CMR procedure, CDT codes for resin-composite and GI restorations (D23XX) were queried; these patients also had treatment notes that indicated CMR. The final data set included patient ID, birth date, gender, dates of treatments, CDT codes, tooth type, tooth surface and existing findings. Two examiners developed guidelines for record review and manually reviewed the clinical notes of patient records to confirm CMR. Only records that were confirmed with the presence of CMR were retained in the final dataset for survival analysis. Survival time was calculated by Kaplan-Meier statistics and a Cox Proportional Hazards model was performed to assess the influence of selected variables (p < 0.05). Results: 214 teeth (115 patients) with CMR were evaluated. Patient average age was 69.4  11.7 years old. Posterior teeth accounted for 78.5 percent (n = 168) of teeth treated. CMRs using GI had a projected 5-year survival rate of 62.9 percent (K-M Analysis) and an 8.9 percent annual failure rate. Cox Proportional Hazards Regression analysis revealed that none of the factors examined (age, gender, tooth type) affected time to failure. Conclusion: CMRs may extend the longevity of crowns with defective margins. Larger EHR studies or case control studies are needed to investigate other variables, such as the caries risk status or the severity of defects that may affect the survival rate of CMRs.

Indiana University-Purdue University Indianapolis (IUPUI) / Objectives: A new technology has been introduced into the field of dental resin composites that professes to enhance light-curing efficiency. Rapid amplified photopolymerization (RAP) initiator technology has not yet been fully compared with resin composites with conventional initiators such as camphorquinone (CQ). The purpose of this study was to compare and contrast the effects of this novel technology (RAP) on properties of two light-cured resin composites. Flowable (EFQ) and microfilled (ESQ) experimental composites were fabricated and supplied from Tokuyama Dental with (w/RAP) and without RAP (w/o RAP). The flexural strength (MPa) and flexural modulus (MPa) were obtained using a three-point bending apparatus (Sintech Renew 1123, Instron Engineering Corp., Canton, MA). Polymerization stress curves were created using a tensometer (American Dental Association Health Foundation, NIST, Gaithersburg, MD) which were then used to calculate the maximum stress rate. Finally, the degree of conversion was measured using infrared spectroscopy (Jassco FT-IR spectrometer, Model: 4100, Jasco Corporation, Tokyo, Japan). When evaluating the flexural strength, the peak stress for EFQ w/RAP was significantly higher than EFQ w/o RAP (p = 0.0001). This was statistically not significant for the ESQ group, even though ESQ w/RAP did have a higher peak stress then ESQ w/o RAP (p = 0.28). The interaction between resin type and RAP was not significant when evaluating the flexural modulus (p = 0.21). Formulations with RAP had a significantly higher flexural modulus then w/o RAP (p = 0.0001). Experimental resins with RAP had significantly higher maximum stress rates than those w/o RAP when evaluating polymerization stress (p = 0.0001). Finally, groups w/ RAP appeared to have a higher degree of conversion than groups without (p = 0.0057). This study showed that the experimental composites with RAP had greater mechanical properties than those without. Unfortunately, the increase in polymerization stress causes concern clinically due to the chance of leakage at the restoration/tooth interface. One of the main potential disadvantages of this new RAP technology is an increase in the polymerization stress. Deciding if this amount of polymerization stress is clinically acceptable is yet to be accomplished.

Indiana University-Purdue University Indianapolis (IUPUI) / A provisional restoration must fulfill biologic, mechanical, and esthetic requirements. These prostheses should provide comfort, pulp protection, positional stability, occlusal function, hygiene access, esthetics, strength and retention. Methyl-methacrylate acrylic has assumed many appli¬cations in the field of restorative dentistry. However, the material still has deficiencies, such as polymerization shrinkage, pulpal damage associated with exothermic polymerization and susceptibility to fracture. Bis-GMA composites, Bis-acryl composites and visible light-cured urethane dimethacrylate resins have been developed to address these issues. The purpose of this study was to compare the mechanical properties of provisional restorations made from composite resins (Protemp Plus, Luxatemp Solar, Radica, Protemp Crown) to those made of the traditional methacrylate resins (Jet, Snap, High Impact). Six groups of samples, two groups from methacrylate and four groups from composite based materials, were fabricated. Samples from each group were evaluated for microhardness (n=10), flexural strength and flexural modulus (n=20) according to ISO 4049, and fracture toughness (n=20) according to ISO 13586. From each of the six groups, ten samples were tested for flexural strength, flexural modulus and fracture toughness and 5 samples were tested for microhardness. These tests were done after storing at 37°C in a distilled water solution for 7 days followed by thermal cycling (2500 cycles, 5-55°C, 45 s. dwell). Identical sets of samples from each group were used as controls; these were tested after storing for 24 hours in dry conditions. The results were analyzed by two-way ANOVA with material type and aging conditions as the two main variables. Significance level was set at p=0.05. For flexural strength and flexural modules, the higher values were obtained for Radica. Protemp plus (7 days) and Radica (24h) had the highest fracture toughness value. Protemp crown showed the highest surface hardness. The mechanical properties of composite resin were superior.

Syftet med den här systematiska litteraturöversikten var att ta reda på om vitala tänder restaurerade med kompositmaterial har högre risk för att utveckla endodontiska komplikationer över tid såsom apikal parodontit eller smärta i jämförelse med tänder som restaurerats med andra dentala fyllningsmaterial som amalgam. Komposit används ofta som ett fyllningsmaterial och även om man studerat kompositers påverkan på t.ex. pulpaceller och funnit att det inte är helt oskadligt är det oklart om materialet faktiskt påverkar pulpan och leder till endodontiska komplikationer. Genomförandet av systematiska litteraturöversikten omfattade (i) formulering av frågeställning, (ii) konstruktion och genomförande av litteratursökning med (iii) tolkning och värdering av den identifierade litteraturen. Den initiala sökningen i databasen PubMed gav 938 publikationer som granskades oberoende av tre personer. Efter ytterligare sökningar kvarstod totalt tio studier som inkluderades i den systematiska litteraturöversikten. Alla inkluderade studier bedömdes ha ett lågt bevisvärde vilket ledde till att ingen konklusion med evidensgrad kunde ges. De inkluderade studierna rapporterar få, om ens några, endodontiska komplikationer och få eller inga skillnader rapporterades vid tänder restaurerade med komposit jämfört med amalgam. Fler väl genomförda studier med ett stort antal patienter krävs för att svara på frågan om tänder restaurerade med kompositmaterial har högre risk för att utveckla endodontiska komplikationer i jämförelse med andra dentala fyllningsmaterial.