Effect of bracket base design on shear bond strength to feldspathic porcelain

OBJECTIVES This study sought to assess the effect of bracket base design on the shear bond strength (SBS) of the bracket to feldspathic porcelain. MATERIALS AND METHODS This in vitro, experimental study was conducted on 40 porcelain-fused-to-metal restorations and four different bracket base designs were bonded to these specimens. The porcelain surfaces were etched, silanized, and bonded to brackets. Specimens were thermocycler, incubated for 24 h and were subjected to SBS. Data were analyzed using Shapiro-Wilk test, Levene's test, one-way ANOVA, and Tukey's honest significant difference test. Adhesive remnant index was calculated and compared using Fisher's exact test. RESULTS One-way ANOVA showed that the SBS values were significantly different among the four groups (P < 0.001). Groups 1, 2, and 4 were not significantly different, but group 3 had significantly lower SBS (P < 0.001). Fractures mostly occurred at the porcelain-adhesive interface in Groups 1 and 2 while in Groups 3 and 4, bracket-adhesive and mixed failures were more common. CONCLUSION The bracket base design significantly affects the SBS to feldspathic porcelain.