Bond strength durability to superficial and deep dentin with the use of dentin pretreatment with TiF4 or incorporated to the primer of a two-step self-etching adhesive system

Abstract

The aim of this study is to evaluate the long-term bond strength to superficial or deep dentin of dentin pretreatment with 2.5% or 4% titanium tetrafluoride (TiF4) or when incorporated into a primer of a two-step self-etching adhesive system (Clearfil SE Bond/ CL). Fifty sound third molars will be sectioned in their longa axis to obtain two slices of each tooth to be embedded and flattened to delimited two zones of equal distances: superficial dentin (SD) and deep dentin (DD). The slices will be separated into groups (n=10): CL; 2.5% TiF4 aqueous solution + CL; 4% TiF4 aqueous solution + CL; 2.5% TiF4 incorporated in CL primer; 4% TiF4 incorporated in CL primer. Five microcylindres will be placed on SD and DD, followed by photocuring of the adhesive system and filling with composite resin. After storage in distilled and deionized water at 370 C for 24 h or 180 days, microshear bond strength tests will be performed in an universal testing machine. The fracture mode will be evaluated in a stereoscopic loupe and surface micromorphological analysis will be performed by the use of SEM images to evaluate the amount and distribution of the dentin tubules. The statistical analysis will be executed according to the homogenous or not homogenous distribution by the use of parametric or non-parametric tests, respectively, adopting the significance level of 5%. (AU)