Effect of selective dentin etching on bond strength durability of dental restorations using universal adhesives

• Grant number: 22/15686-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2023
• End date: June 30, 2024
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Anderson Catelan
• Grantee: Pedro Henrique Faneco Garroti
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Aim: To evaluate the effect of selective dentin etching on the durability of bond strength of resin composite restorations using different universal adhesive systems, before and after thermal cycling. Material and method: The buccal surface of forty-eight bovine incisors will be ground to expose the middle dentin, then the teeth will be divided (n = 8) according to selective dentin etching (no and yes), adhesive composition [with 2-hydroxyethyl methacrylate (HEMA) and Bisphenol A (BPA): Single Bond Universal (3M), BPA-free: Scotchbond Universal Plus (3M), and BPA and HEMA-free: Prime&Bond universal (Dentsply Sirona) and Zipbond Universal (SDI Ltd.)] and evaluation period (24 h and after thermal cycling). In self-etching mode, two layers of universal adhesives will be actively applied for 20 s, excess adhesive will be removed and light curing will be performed. Selective dentin etching will be performed with 35% phosphoric acid for 3 s, followed by washing, drying maintaining dentin moisture, and application of adhesive as previously described. Then a rectangular block (3.5 x 4.8 mm and 3 mm of thickness) of composite will be made in a single increment. Light curing of materials will be carried out for the time recommended by the manufacturers with a polywave LED at an irradiance of 1,000 mW/cm2. Specimens will be cut into 1 x 1 mm beams, and half of the sticks will be evaluated after 24 h or 20,000 thermal cycles (5 and 55ºC, residence time of 30 s). Bond strength by the microtensile test will be obtained using a semi-universal testing machine. Method of analysis of the results: Data obtained will be tabulated, analyzed, and submitted to the most appropriate statistical tests, adopting a significance level of 5%. Expected results: Selective dentin etching for 3 s with phosphoric acid is expected to increase and maintain stable bond strength of the adhesive restoration to the tooth.