Microtensile Bond Strength to Enamel Affected by Hypoplastic Amelogenesis Imperfecta

Purpose: This study compared the microtensile bond strengths (μTBS) of two different self-etching (SE) and etchand- rinse (ER) adhesive systems to enamel affected by hypoplastic amelogenesis imperfecta (HPAI) and analyzed the enamel etching patterns created by the two adhesive systems using scanning electron microscopy (SEM). Materials and Methods: Sixteen extracted HPAI-affected molars were used for the bond strength tests and 2 molars were examined under SEM for etching patterns. The control groups consisted of 12 healthy third molars for μTBS tests and two molars for SEM. Mesial and distal surfaces of the teeth were slightly ground flat. The adhesive systems and composite resin were applied to the flat enamel surfaces according to the manufacturers' instructions. The tooth slabs containing composite resin material on their mesial and distal surfaces were cut in the mesio-distal direction with a slow-speed diamond saw. The slabs were cut again to obtain square, 1-mm-thick sticks. Finally, each stick was divided into halves and placed in the μTBS tester. Bond strength tests were performed at a speed of 0.5 mm/min. Data were analyzed with two-way ANOVA and Tukey's tests. Results: There was no significant difference between the bond strength values of ER and SE adhesives (p > 0.05). However, significant differences were found between HPAI and control groups (p 0.05). HPAI-affected enamel surfaces exhibited mild intra- and inter-prismatic enamel etching patterns after orthophosphoric acid application, while conditioning of HPAI-affected enamel with SE primer created a slightly rough and grooved surface. Conclusion: SE and ER adhesive systems provide similar bond strengths to HPAI-affected enamel surfaces. Keywords: Amelogenesis imperfecta, bond strength, microtensile, self-etch adhesive, etch-and-rinse adhesive