Comparison of Bromelain Enzyme, Sodium Hypochlorite, and Titanium Tetrafluoride on Shear Bond Strength of Restorative Composite to Dentin: An in vitro Study

STATEMENT OF THE PROBLEM: Sufficient bond strength of composite restoration leads to its durability and survival; therefore, preparation of dentin surface for higher bond strength is essential. PURPOSE: Our aim is to assess the deproteinizing effect of 3% bromelain enzyme and compare it to 4% titanium tetrafluoride (TiF4) and 5% sodium hypochlorite (NaOCl) regarding the shear bond strength (SBS) of composite resin to dentin. MATERIALS AND METHOD: In this experimental study, 40 intact extracted human maxillary premolars were selected, and the occlusal surfaces of the teeth were sectioned at a depth of 2 mm from dentinoenamel junction. The teeth were divided into 4 groups (n=10). In Group 1, the teeth were etched with 37% phosphoric acid gel. In Group 2, the teeth were etched and deproteinized with 5% NaOCl. In Group 3, the teeth were etched and deproteinized with 4% TiF(4). In Group 4, the teeth were etched and deproteinized with 3% bromelain enzyme. In each specimen, composites with 3 mm diameter and 2 mm height were prepared and cured. The test specimens were then stored in distilled water at room temperature for 7 days before conducting the SBS test (MPa). By universal testing machine at a crosshead speed of 1 mm/min, the results were analyzed using one-way ANOVA and Tukey test. RESULTS: One-way ANOVA test demonstrated that pretreatment of dentin with a bromelain enzyme, TiF(4) solution, or NaOCl was not statistically different regarding SBS to dentin (p= 0.790). CONCLUSION: 3% bromelain enzyme can be as effective as TiF4 and NaOCl and phosphoric acid 37% in terms of the SBS of composite resin to dentin.