Bonding to Sclerotic Dentin: Effect of Bur Roughening and EDTA

Objectives: The objectives of this study was to evaluate the influence of the bur roughening and EDTA conditioning of bovine sclerotic dentine on the micro-tensile bond strength (m-TBS) of two self-etch adhesive systems. Materials and methods: Eighty bovine incisors were divided into 16 groups (n = 5) according to the combination of 1) surface treatment: no treatment [NT]; roughening with a coarse-grit [grain size of 151μm], medium-grit [grain size of 91μm], fine-grit [grain size of 46 μm] diamond burs 2) Conditioning with distilled water [DW] and EDTA and 3) Adhesive system (Clearfil SE Bond (Kuraray) [CSE] and Adper SE Plus (3MESPE) [ADSE]). The exposed surfaces were firstly roughned with one of the above burs, followed by conditioning with DW or EDTA for 2 min. Then, the adhesives were applied according the manufacturer's directions. After the restoration with composite resin, specimens were stored in distilled water (24 h/37°C) before being perpendicularly cut with a low-speed diamond saw to obtain bonded resin-dentin beams with a cross-sectional area of 0.8 mm². The bonded sticks were tested in tensile stress at 0.5 mm/min. Data was submitted to a three-way ANOVA and Tukey's test (alfa=0.05). Results: The results (MPa) are summarized in the table below. Only the main factors Adhesive system and EDTA treatment were significant (p<0.05). Higher mTBS values were observed for CSE and after EDTA treatment, regardless the other experimental conditions.

Conclusion: Roughening the sclerotic dentin with Diamond burs did not affect the overall MTBS, however the conditioning with EDTA seems to improve the mTBS of self-etch adhesives to sclerotic dentin.