Influence of surface pretreatment of fiber posts on cement delamination

Objectives. To evaluate the influence of post surface pretreatment on the delamination strength of different cements from a prefabricated FRC post tested in a three-point bending test. Methods. Three cements were tested; RelyX Unicem, DC Core Automix, and Panavia F2.0. Per cement, 40 posts (D.T. Light Post Illusion size 3) were divided into four groups; no pretreatment (control), sandblasting, silanization, and sandblasting followed by silanization. A cement layer was applied to the posts using a standardized poly-oxy-methacrylate mold. The specimens were subjected to a three-point bending test recording the initial and catastrophic failure loads. Two-way ANOVA and Tukey post-hoc tests were used to analyze the differences between the variables. Results. At the initial failure load, all specimens demonstrated delamination of the cement layer, therefore initial failure load was defined as delamination strength. With RelyX Unicem, none of the pretreatments showed significant differences. When using Panavia F2.0, silanization (735 +/- 51MPa) resulted in higher initial failure values than sandblasting (600 +/- 118MPa). When DC Core Automix was used, silanization (732 +/- 144MPa) produced significantly higher initial failure values than the no pretreatment group (518 +/- 115MPa) and the combined sandblasting and silanization group (560 +/- 223MPa). Two failure types were observed; cohesive and adhesive failure. In the silanization groups, more cohesive failures were observed for all cements tested. Significance. Especially when non self-adhesivecements are used, silanization of fiber posts has a beneficial effect on cement delamination strength and failure type. (C) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.