Biodegradation influence by S. mutans cariogenic biofilm in thephysico mechanical properties of Bulk Fill composites

Author(s)

Jessica Rodrigues Camassari

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2018-06-07

Examining board members

Andreia Bolzan de Paula; Giovana Spagnolo Albamonte de Araújo; Mário Alexandre Coelho Sinhoreti

• Advisor: Andreia Bolzan de Paula; Regina Maria Puppin Rontani

Abstract

The aim of this study was to evaluate the influence of biofilm by Streptococcus mutans on the roughness (Ra), gloss (GU), surface hardness (KHN) and flexural strength (FS) of high viscosity bulk fill composites. Methods: Filtek Bulk Fill (FBF), Tetric N Ceram (TNC), X-tra fil (XF) and Filtek Z350 (FZ- control) were used in this study. Ten discs of each composite were prepared with 5 mm diameter x 2 mm thickness for the Ra and KHN tests, and 10 discs with dimensions of 10 mm in diameter x 2 mm in thickness for the GU assay. For RF, 20 samples of each composite (10 for initial analysis and 10 for final analysis) were made with dimensions 25 mm long x 2 mm wide x 2 mm thick. After 24 hours of incubation at 37ºC, all samples were polished and submitted to the initial assays of Ra, GU, KNH and RF. All the samples were sterilized with ethylene oxide and subjected to degradation by S.mutans for 7 days and Ra, GU, KHN and RF reassessed. Three representative samples of each group were evaluated in Scanning Electron Microscope (SEM). After normality testing, data from Ra, GU and KHN were subjected to two-way ANOVA for repeated measures and the data from RF to ANOVA two factors and Tukey's test (p <0.05). For Ra there was a significant interaction between factors. Before the biodegradation, the XF (0.1251) presented higher values of Ra when compared to the other materials, which showed similar values. After biodegradation, XF (0.3100) presented higher values of Ra and FZ (0.1443) the smaller, while TNC and FBF were similar. iofilm increased of Ra in all materials. There was no interaction between the factors for GU. Higher GU values were observed for FZ (71.7 initial and 62.0 final) and FBF (69.0 initial and 64.6 final) and the lowest for TNC (61.4 initial 53.3, final) and XF (58.5 initial and 53.5 final), both before and after biodegradation. Degradation promoted a decrease in GU for all materials. There was significant interaction between the material x biodegradation factors in KHN values. Higher values were obtained by XF (151.7 and 106.0, respectively) and the lower values for TNC (62.2 and 51.8, respectively), both before and after biodegradation, while FBF and FZ were similar. Biodegradation reduced KHN in all materials. There was interaction between the factors in the RF values. Higher initial RF values were observed for FZ when compared to TNC. After biodegradation, XF presented higher values when compared to TNC and FBF. Biodegradation promoted reduction in RF values only for FZ. It was concluded that biodegradation negatively affected the surface properties of Bulk Fill composites; however, did not affect the flexural strength of these materials, unlike control composite (AU)

• FAPESP's process: 16/18720-8 - Biodegradation influence by s. mutans cariogenic biofilm in the physicomechanical properties of Bulk Fill composites
• Grantee: Jéssica Rodrigues Camassari
• Support Opportunities: Scholarships in Brazil - Master