Evaluation of Shear Bond Strength of Incremental Layer of Self-etch Self-adhesive Novel Flowable Composite after Salivary Contamination: An In-vitro Study

Abstract

Introduction: Contamination of composite restoration during incremental placement leads to decrease in the incremental bond strength. Adhesive application on freshly contaminated resin surface increases the bond strength but is a complex and time-consuming procedure. Recently composite systems combining etchant, bonding agent and flowable composite into a single component have been introduced to simplify bonding and save time. In this study incremental layer shear bond strength is utilised to assess bond stability at resin-resin interface after salivary contamination. Aim: To evaluate shear bond strength of incremental layer of self-etch self-adhesive novel flowable composite after salivary contamination. Materials and Methods: The present in-vitro experimental study included 55 acrylic resin cylinders (2×2.5 cm) with square shaped cavity (5×5 mm, thickness 2 mm) restored with DMGTM Constic flowable composite that were randomly divided into five groups with eleven specimens per group. Group I: No salivary contamination, Group II: Salivary contamination followed by air drying, Group III: Salivary contamination followed by rinsing and air drying. Group II and III were subdivided into subgroup a: application and brushing of 0.5 mm of Constic followed by light curing and filling of rest of mold by Constic, subgroup b: direct application of 2 mm of Constic. Shear bond strength between increments of composite was determined by universal testing machine. Data were analysed using One-way ANOVA test and Independent t-test. Level of significance was kept at 5%. Results: Incremental shear bond strength (MPa) was highest for group I (12.09±1.99) followed by group IIIa (10.21±3.49), group IIa (10.08±3.21), group IIb (7.59±2.31) and lowest for group IIIb (7.35±3.06). Conclusion: Active application of self-etch self-adhesive flowable composite successfully restores the incremental shear bond strength after salivary contamination.

Keywords

• adhesive
• bond stability
• resin-resin interface
• saliva