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Objective: This study evaluated Proanthocyanidin protective effect on dentin subjected to erosion and its inhibition on degradation of the demineralized organic matrix (DOM). Material and Methods: The tested groups were: G1 - 10% Proanthocyanidin gel (test group), G2 - 1.23% NaF (positive control 1), G3 - 0.012% Chlorhexidine (positive control 2) and G4 ­ Placebo (negative control with no active compound) and two methodologies were performed: contact profilometry and ICTP ELISA method. To quantify dentin wear, profilometry was performed. Data were submitted to Analysis of Variance followed by Fisher's LSD Test. To assess the collagen degradation, ICTP ELISA method was performed. Data were submitted to the Kruskal-Wallis followed by the Dunn ́s test. Simple linear regression and Pearson Correlation test were also performed (p<0.05). Results: The profilometry showed significantly lower wear of G1 when compared to other groups and G2, G3 and G4, which did not present significant difference among them. In the ICTP ELISA analysis, G1 and G4 did not show significant differences and the same happened between G2 and G3. However, G1 and G4 had lower values of collagen degradation compared to groups G2 and G3. Data showed that degraded DOM is a significant predictor to explain the values obtained through the ICTP ELISA. Conclusions: The results allow to verify that 10% proanthocyanidin provided less tooth wear and decreased degradation of the DOM, suggesting a good ability to prevent dentin erosion. The regression analysis also suggests that contact profilometry is a good strategy to quantify dentin wear (AU)

Objetivo: Este estudo avaliou o efeito protetor da proantocianidina na dentina submetida à erosão e sua inibição na degradação da matriz orgânica desmineralizada (MOD). Material e Métodos: Os grupos testados foram: G1 - gel de Proantocianidina 10% (grupo teste), G2 - NaF 1,23% (controle positivo 1), G3 - Clorexidina 0,012% (controle positivo 2) e G4 - Placebo (controle negativo sem princípio ativo) e duas metodologias foram realizadas: perfilometria de contato e método ICTP ELISA. Para quantificar o desgaste da dentina, a perfilometria foi realizada. Os dados foram submetidos à Análise de Variância seguida do Teste LSD de Fisher. Para avaliar a degradação do colágeno, foi realizado o método ICTP ELISA. Resultados: Os dados foram submetidos ao teste de Kruskal-Wallis seguido do teste de Dunn. Regressão linear simples e teste de correlação de Pearson também foram realizados (p<0,05). A perfilometria mostrou desgaste significativamente menor do G1 quando comparado aos outros grupos e G2, G3 e G4, que não apresentaram diferença significativa entre si. Na análise ICTP ELISA, G1 e G4 não apresentaram diferenças significativas e o mesmo ocorreu entre G2 e G3. No entanto, G1 e G4 apresentaram valores menores de degradação do colágeno em relação aos grupos G2 e G3. Os dados mostraram que a MOD degradada é um preditor significativo para explicar os valores obtidos pelo ICTP ELISA. Conclusão: Os resultados permitem verificar que a proantocianidina a 10% proporcionou menor desgaste dentário e diminuição da degradação da MOD, sugerindo uma boa capacidade de prevenir a erosão dentinária. Também sugere que a perfilometria de contato é uma boa estratégia para quantificar o desgaste da dentina (AU)

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PURPOSE: Concurrently with the growing interest in CAD-CAM systems, several new materials of different chemical nature have become available. As an alternative to ceramics, numerous polymer-based materials have recently been proposed for permanent prosthetic restorations. Aim of this study was to test the CAD-CAM polymer-based materials available on the market, comparing mean flexural strength, Weibull characteristic strength and Weibull modulus. METHODS: Seven types of polymer-based blocks were tested: Lava Ultimate, 3M; Brilliant Crios, Coltene; Cerasmart, GC; Block HC, Shofu; Katana Avencia, Noritake; Grandio Blocs, Voco; Tetric CAD, and Ivoclar-Vivadent. Specimens were cut out from blocks, finished, polished, and tested in a three-point bending test apparatus until failure (n=30). Flexural strength, Weibull characteristic strength, and Weibull modulus were calculated. Flexural strength data were statistically analyzed. ANOVA on Ranks was applied, followed by the Dunn's test for post hoc comparisons (P= 0.05). RESULTS: Flexural strength values (MPa) were measured (mean±standard deviation). Different letters in parentheses label statistically significant differences: Grandio Blocs 266±24(a), Brilliant Crios 259±21(ab); Tetric CAD 254±15(ab); Katana Avencia 241±29(bc); Cerasmart 221±24(cd); Lava Ultimate 196±23(de); Block HC 139±10(e). All the tested materials had flexural strengths greater than 100 MPa, thereby satisfying the requirements of ISO standards for polymer-based materials. For all the tested materials the Weibull characteristic strength was greater than 100 MPa. Weibull modulus ranged between 21.20 (Tetric CAD) and 9.09 (Katana Avencia). CLINICAL SIGNIFICANCE: Even though all the CAD-CAM polymer-based materials marketed in blocks tested in the present study satisfy the requirements of ISO standard for polymer-based materials, their flexural resistance differs significantly. The data presented in the study may be helpful to clinicians for selecting the most appropriate materials for each clinical case.

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