Efeito das variações de pH e do ácido gástrico na superfície de resinas compostas de incremento único

• Autor(a) principal: Somacal, Deise Caren
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/7896
• topic: Resinas Compostas; Desmineralização do Dente; Remineralização Dentaria; Escovação Dentária; Propriedades de Superfície; Aderência Bacteriana; Ácido Gástrico; CIENCIAS DA SAUDE::ODONTOLOGIA

(Artigo 1 Efeito das variações do pH na superfície de resinas compostas de incremento único) Aim: To evaluate, in vitro, quantitatively and qualitatively, the effect of pH variations on surface roughness (Ra) and bacterial adhesion (Cn) of Bulk-Fill composite resins followed by simulated toothbrushing. Materials and Methods: Thirty samples of each composite resin were obtained: G1 (control): Z250; G2: Filtek Bulk-Fill (FTK); G3: Tetric N Ceram Bulk-Fill (TTC); G4: Aura Bulk-Fill (AUR). After 24 h, the samples were polished and then alternated by DES/RE solutions for 15 cycles of 24 h each at 37°C. Then, the samples were submitted to simulated toothbrushing. The Ra and Cn measurements were quantitatively analyzed in three stages: after polishing (Ra0 and Cn0), after pH cycles (Ra1 and Cn1) and after simulated toothbrushing (Ra2 and Cn2). Measurements on new samples submitted only to simulated toothbrushing were also performed (Ra* and Cn*). The Ra values were submitted to two-way ANOVA, followed by the Tukey’s test (α=0.05). The Kruskal-Wallis test followed by multiple comparisons was applied for Cn analysis. Surface topography and bacterial adhesion were observed by Scanning Electron Microscopy (SEM). Results: Z250, FTK and TTC showed no significant change in Ra regardless of the treatment performed, except for AUR which obtained superior Ra at Ra2 (p <0.05). In the bacterial count, FTK differed from the others in Cn0 and Cn1. In Cn2 there was no difference between the composite resins. Only after Cn*, the Z250 differed from all other materials. SEM images showed cracking and exposure of fillers in Ra1, with detachment of the exposed fillers. Microcavities were observed in all composite resins in Ra2. Bacterial adhesion occurred in all composite resins regardless of the treatment. There was greater bacterial adhesion in Cn1 for Z250 and FTK. Conclusion: The pH cycles did not alter the Ra of composite resins Z250, FTK, TTC and AUR. Simulated toothbrushing after pH cycles caused Ra increase only for AUR, and reduced bacterial adhesion in Z250 and FTK composite resins. There was degradation of the surface of all composite resins, as well as bacterial adhesion. (Artigo 2 Effect of gastric acid on the surface of bulk-fill composite resins) Aim: To evaluate, in vitro, quantitatively and qualitatively, the effect of gastric acid on surface roughness and bacterial adhesion in Bulk-Fill composite resins followed by simulated toothbrushing. Materials and Methods: 30 samples of each Bulk-Fill composite resin were obtained: G1 (control): Z250; G2: Filtek Bulk- Fill (FTK); G3: Tetric N-Ceram Bulk-Fill (TTC); G4: Aura Bulk-Fill (AUR). The samples were polished after 24 h and immersed in 10 ml of gastric acid for 24 h at 37°C. Following, the samples were submitted to simulated toothbrushing. Ra and Cn were obtained in three different stages: initial (Ra0 and Cn0), after gastric acid (Ra1 and Cn1) and after gastric acid and simulated toothbrushing (Ra2 and Cn2). Additional samples were submitted to the simulated toothbrushing test only and received the same measurements (Ra* and Cn*).Two-way ANOVA was used to evaluate Ra, followed by the Tukey test. Regarding the Cn analysis, the Kruskal-Wallis test was used, followed by multiple comparisons. The significance level was of 5%. Results: Z250 and FTK had a significant increase in surface roughness in Ra1. In Ra2, the four composite resins did not significantly differ from Ra0, but there was a significant reduction of the means in Ra2 of Z250 and FTK compared to Ra1. For Cn, Z250 and FTK allowed an increased biofilm accumulation in comparison with TTC and AUR. SEM images showed crack formation and exposure of fillers in Ra1, occurring detachment of the exposed fillers. Microcavities were observed in all composite resins in Ra2. Bacterial adhesion occurred in all composite resins regardless of the treatment. There was higher bacterial adhesion in Cn1, followed by reduction of bacterial adhesion in Cn2 for all tested materials, except for AUR. Conclusion: Gastric acid increased the surface roughness of Z250 and FTK composite resins, as well as promoted higher bacterial accumulation compared to TTC and AUR composite resins. There was degradation of the surface of all composite resins, as well as bacterial adhesion.