Effect of dentifrice with high concentration of fluoride under remineralization and bond strength of glass ionomer cement on dental substrates with artificial caries.

Author(s)

Diego Felipe Mardegan Gonçalves

• Document type: Master's Dissertation
• Press: Araçatuba. 2021-10-06.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2021-07-08
• Advisor: Ticiane Cestari Fagundes

Abstract

The aim of the present study was to evaluate the influence of different dentifrices on surface hardness and cross-sectional hardness, wear profile on enamel, as well as on the bond strength of high viscosity glass ionomer cements (HV-GIC) to dentin, after to produce artificial caries, pH cycling and brushing. Eighty bovine teeth were used, divided into enamel and dentin blocks. The enamel specimens were polished and selected according to microhardness. Then, half of each enamel block was covered with resistant acid varnish. Dentin specimens were embedded in acrylic resin and flattened. The artificial caries protocol was carried out through enamel demineralization cycles (n= 20), and the dentin (n= 40) was immersed in demineralizing solution. Twenty dentin specimens were not subjected to artificial caries, being the control group. All blocks were subjected to pH cycling and brushing for 7 days according to each dentifrice: Colgate Total 12 1450 ppm F (CT) and Clinpro 5000 ppm F + TCP (CL). Then, the protected enamel surfaces were exposed for the analysis of surface hardness, cross sectional hardness and profilometry. Scanning electron microscopy was performed in three representative blocks of each group. The dentin specimens were subdivided according to restorative material: HV-GIC Ketac Molar (KM), and hybrid GIC Equia Forte (EF). Then, the specimens were stored under relative humidity for 24 hours and prepared for the micro-shear test. The data were submitted to normality test, one-way analysis of variance (ANOVA) to assess mineral recovery and wear, two-way repeated measures ANOVA to assess surface and cross-sectional hardness, and three-way ANOVA to analyze the bond strength. Tukey post-test was used for multiple comparisons, with a significance level of 5%. It was observed a partial recovery of superficial microhardness, regardless of the dentifrice. Cross sectional hardness data showed that CL obtained values below CT up to 90 micrometers (m) on the test side. CT dentifrice presented greater wear when compared to CL. In dentin, when the dentifrices were compared within each GIC, CT showed greater adhesive resistance for both materials. A comparison between GICs within the same dentifrice showed superior adhesive resistance for KM when compared to EF in dentin treated with CL. It was concluded that the dentifrice with the highest fluoride concentration promoted less cross-sectional hardness in the enamel and the conventional dentifrice resulted in greater surface wear. On the dentin, the dentifrice with the highest fluoride concentration decreased the adhesive strength of glass ionomer cements. (AU)

• FAPESP's process: 19/13326-8 - Effect of dentifrice with high concentration of fluoride under remineralization and bond strength of glass ionomer cement on dental substrates with artificial caries
• Grantee: Diego Felipe Mardegan Gonçalves
• Support Opportunities: Scholarships in Brazil - Master