Effect of contamination by hemostatic agents and cleanup of contaminated cavities on the bond strength between composites and tooth structure

• Grant number: 11/20735-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2012
• End date: December 31, 2012
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: César Rogerio Pucci
• Grantee: Mirella Anjos de Sousa
• Host Institution: Faculdade de Odontologia (FOSJC). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

This study aims to evaluate the interference in the bond strength between dentin and composite resin restoration, of contamination by hemostatic agents, and cleaning agents, based on the push-out test. 84 bovine incisors will be selected and cut by a plane parallel to the long axis of the tooth, separating the buccal and lingual faces. Then be worn on the buccal to the exposure of the dentin. In the central block of dentin standard 2mm thick, is made a conical cavity with the aid of a diamond tip # 3131, engaged in preparations for normalizing machine. The specimens will be divided into four groups (n = 12) and all the wells will be held for the etching according to the manufacturer's instructions. Group 1 (control - no contamination, only acid etching and composite resin restoration in accordance with the manufacturer's instructions), Group 2 (ViscoStat contamination), Group 3 (Hemosthasegel contamination), Group 4 (Hemostop contamination). Groups 2, 3, and 4 will be subdivided into two subgroups according to the cleaning protocol adopted. Subgroup A - no cleaning agent, only contamination subgroup B - cleaning with chlorhexidine 0,2%. In all wells restorative procedure will be standardized: the bonding Adper Single Bond 2 will be applied according to the manufacturer's instructions and composite Z350 XT will be inserted into a single increment. The samples will then be submitted to the protocol of aging by a thermomechanical cycler. Bond strength is determined using the push-out test using the Instron universal testing machine, with a compressive loading speed of 0.5 mm/min until the displacement of the restoration. During the push-out test, the dentin block will always remain with the smallest diameter of the cavity side up, in contact with the tip of universal testing. The results will be evaluated by the resistance values obtained in MPa. These values of the push-out test will be submitted to descriptive and inferential statistical analysis using ANOVA and Tukey tests with a significance level of 5%. Data from the stereoscopic patterns of fracture will be submitted to the Kruskal-Wallis.(AU)