Assessment of Enamel Bond Strength of Hypoplastic Primary Teeth

Purpose: The purpose of this study was to compare the enamel bond strength of hypoplastic and healthy primary teeth. Methods: Twenty-five hypoplastic teeth (experimental group) and 25 healthy primary teeth (control group) were selected and conditioned with 35 percent orthophosphoric acid before a two-layer adhesive system (Single Bond) was applied. Composite resin (Filtek 2350) was inserted in a single application, two-mm high and one-mm in diameter, and then light-cured for 20 seconds. After being stored in distilled water for 24 hours, the specimens were submitted to a shear bond strength test. Fractures were analyzed under a stereomicroscope. Results: No significant differences in bond strength were observed between the experimental group (70.27 +/- 20.40 MPa) and control group (67.84 +/- 23.37 MPa; P>0.05). However, adhesive fractures were more frequently observed in healthy teeth (72 percent) while hypoplastic teeth presented mixed fractures (60 percent) and enamel cohesive fractures (36 percent). Conclusions: The shear bond strength of the enamel of hypoplastic primary teeth was similar to that of healthy teeth. However, distinct characteristics were observed in the dental samples following fracture.