Resin bonding to root dentin: Influence of the alveolar bone level and thickness of the cement layer

Abstract

Aim: Aim of the present study was to evaluate the influence of the alveolar bone level and thickness of the cement layer on the push-out bond strength of fiber posts luted to root dentin. Methods: We prepared post spaces in 60 bovine roots (16 mm), embedded in acrylic resin to simulate different scenarios of alveolar bone resorption. They were divided into six groups (N.=10), according to the factors alveolar bone level (14,10, and 7 mm) and cement thickness (post no. 3/control and post no. 1/thicker cement layer): G14P3-14-mm root + post n. 3; G10P3-10-mm root + post n. 3; G7P3-7-mm root + post n. 3; G14P1-14-mm root + post n. 1; G10P1-10-mm root + post n. 1; and G7P1-7-mm root + post n. 1. The fiber posts (White Post DC, FGM) were luted, and composite cores were made. Each specimen was subjected to mechanical cycling, and four slices were obtained from each root specimen and subjected to pushout testing in a universal testing machine. The data (MPa) were analyzed by ANOVA (two way) and Tukey's test (5%). Results: The factor cement thickness (P=0.0057) significantly influenced bond strength, but the factor alveolar bone level (P=0.0605) did not. The thicker cement layer/post n. 3 presented bond strength values higher than those with cement layer/post n.l. Conclusion: Bond strength was not influenced by different scenarios of alveolar bone resorption, although higher bond strength values were found for thinner cement layers.