Interface homogeneity of adhesively luted glass fiber posts

Objective The aim of this study was to light microscopically evaluate the homogeneity of the cement interface of an adhesively luted glass fiber post (GFP) by using a new cement application aid compared to a conventional post cementation method. Methods Twenty artificial root canals (n = 5) received GFP under the following experimental conditions: I = RelyX™ Unicem applied with a new application aid, II = RelyX™ Unicem, III = Panavia F 2.0 and IV = Variolink II (groups II–IV with conventional post cementation). From all specimens standardized photographs were taken perpendicularly to the post surface under a light-optical microscope from two opposite sides. The depicted cement interfaces were analysed using surface-analyzing software and related to the complete three-dimensional surface of the cement interface. Non-parametric tests were used to compare median values of the observed inhomogeneities (α = 5%). Results The median values (%) of inhomogeneities within the cement interface for the cervical, middle, and apical level of analysis were: I = 2, 2, 7; II = 15, 19, 24; III = 8, 16, 39; IV = 11, 16, 29. For the complete post length, median values (%) of inhomogeneities were: I = 4; II = 19; III = 20; IV = 18. Significance The conventional application technique for luting endodontic post results in a large number of voids and bubbles. The combination of a flexible root-canal-shaped application aid achieves a more homogenous cement interface for the self-adhesive luting material tested.