Microshear bond strength of 2-step self-etching adhesives: effect of different treatments on dentin with different degrees of mineralization

• Grant number: 13/06386-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2013
• End date: July 31, 2014
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Edson Alves de Campos
• Grantee: Gabriela Ohata
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

The objective of this study is to evaluate the microshear bond strength of different 2-step self-etching adhesive systems, with different degrees of acidity, under different treatments: etching, laser, and diamond bur, in dentin with different degrees of mineralization. One hundred and twelve bovine incisors will be selected. The buccal surface will be abraded to expose the flat dentin surface. The teeth are randomly divided into two different groups according to the type of dentin: normal (N) (n = 54) and artificially hypermineralized (H) (n = 58). The teeth of group H will be submitted to artificial hypermineralization and, after this process, four teeth will be randomly selected and observed in a scanning electron microscope (SEM) to confirm the efficacy of the procedure. The teeth of each group will be randomly divided into two different subgroups, according to the adhesive system used: Clearfil SE Bond and AdheSE. For each adhesive system, in each condition of dentin (H and N), different dentin treatments will be evaluated: (1) conventional conditioning - application of the adhesive system according to recommendations of the manufacturer (control group), (2) conditioning of the dentin surface with Er, Cr: YSGG laser (Waterlase Millennium, Biolaser Technology, San Clement, CA, USA) + adhesive system according to recommendations of the manufacturer, (3) roughening of the dentin surface with a diamond bur + adhesive system according to recommendations of the manufacturer. Then transparent cylindrical tubes will be positioned on each dentin surface treated with adhesives tested and will be filled with composite resin (Z350 XT FiltekTM - 3M ESPE) and photoactivated for the 20s. After a storage period of 24 hours in water at 37 ° C, the specimens will be adapted to a device for micro shear bond strength testing machine with a load speed of 0.5 mm/min. Subsequently, the fracture pattern of each specimen will be determined. One sample from each group will be prepared in order to evaluate the morphology of the interface and/or appearance of tags resin by SEM. Differences between groups will be determined using appropriate statistical tests. (AU)