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% tif4. 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 oneway anova and tukey test. results: oneway anova test demonstrated that pretreatment of dentin with a bromelain enzyme, tif4 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.