Effect of termocycling and polymerization delay of glass ionomer linning on the adhesive interface dentin/resin

• Grant number: 08/02747-8
• Support Opportunities: Regular Research Grants
• Start date: November 01, 2008
• End date: October 31, 2010
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Maria Teresa Atta
• Grantee: Maria Teresa Atta
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

The aim of this study is to analyze the influence of glass-ionomer cement as a liner on the adhesive interface dentin/resin, evaluating the effect of polymerization delay time of resin-modified glass-ionomer cement (RMGIC) and thermocycling aging. Occlusal cavities will be done in ninety humans extracted molars, divided in two experiments: Experiment A (thermocycling aging) and Experiment B (polimerization delay time of RMGIC). The experiment A will be subdivided into 6 groups: (A1 and A4) no linning, (A2 and A5) glass-ionomer cement (CGI) (Ketac Molar Easymix) and (A3 and A6) RMGIC (Vitrebond). The Experiment B will be subdivided into 3 groups: (B1) linning polymerized for 40s (Vitrebond), (B2) linning not polymerized and (B3) linning with 10s polymerization delay time. Resin composite (Filtek Z250) will be placed after adhesive system Adper Single Bond 2 application, which would have been mixed with fluorescent reagent (Rhodamine B) for confocal microscope analysis. After that, the specimens of the groups A1, 2, 3 and B will be stored in destilled water at 37°C, while the specimens of the groups A4, 5, 6 will be thermocycled into 2 baths (5ºC - 55ºC) of 30s each in 10.000 cycles. After this period, tooth will be sectionated in 0,8mm slices. One slice of each tooth will be randomly selected for analyzis in Confocal Microscopy. The other ones will be sectionated in sticks, which will be submitted to microtensile test. The results will be analyzed by ANOVA 5% and Tukey test. (AU)