Effect of natural agents on the bond strenght between dentin/adhesive on eroded substrate

Abstract

The aim of this study is to evaluate the effect of Bromelain and Propolis extract, on the bond strength (BS) of the adhesive to artificially eroded dentin. For that, sound human molar teeth will be selected, which the roots will be embedded in acrylic resin in PVC tubes with the occlusal surfaces parallel to the horizontal plan. The occlusal surfaces will be flattened. Each teeth will have its superficial dentin area isolated with composite resin and used as control. The unprotected half will be submitted to the erosive challenge for 10 days with a 0,05M citric acid solution (pH 2.3, Anhydrous citric acid; Merck, Darmstadt, Germany) six times per day for 5 minutes under agitation (Go Shaker SK - O180 - Pro, Scilogex, Rocky Hill, CT, USA). On every cycle the samples will be stored in a remineralizing solution for 60 minutes (1,5 mM CaCl2, 0,9mM NaH2PO4, e 0,15 M KCl - pH 7). Teeth will be randomly separated in 3 groups, according to the surface treatment to which the substrates will be submitted: Control group - Adhesive; Group Br - 10% bromelain extract; Group Pr - Propolis extract. After the dentin treatment the samples will be restored and cut in sticks (0,9mm2), and then will be stored in artificial saliva at 37ºC for 24 hours and 6 months. After the storage period, the sticks will be submitted to the microtensile bond strength test (0.5 mm/min) until fracture. The fracture patterns will be observed with a digital microscope (VH-M100, Keyence) and the adhesive interface with scanning electron microscopy (SEM). The bond strength values will be analyzed with the most appropriate statistical test. (AU)