Influence of surface pretreatment of fiber posts on cement delamination

The aim of the study is to evaluate the influence of post surface pretreatment on the delamination of different cements to a prefabricated fiber reinforced composite post(D.T. Light Post Illusion size 3) 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 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 (D.T. Light Post bur size 3) poly-oxy-methacrylate mold. The specimens were subjected to a three-point bending test recording the initial failure loads. Initial failure was defined as the load at the first dip in the stress-strain curve. 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. The pooled data of RelyX unicem (743±128 MPa) showed higher failure values than DC Core Automix (667±137 MPa). When comparing the pooled data of the experimental groups, silanization (711±144 MPa) produced significantly higher failure values than sandblasting (614±87 MPa) of the posts. With RelyX Unicem, none of the pretreatments showed significant differences. When using Panavia F2.0, silanization (735±51 MPa) resulted in higher failure values than sandblasting (600±118 MPa). When DC Core Automix was used, silanization (732±144 MPa) produced significantly higher failure values than the no pretreatment group (518±115 MPa) and the combined sandblasting and silanization group (560±223MPa).

Conclusions:

Within the limitations of this study it was shown that silanization of a fiber post results in a stronger bond with DC Core Automix compared to no pretreatment of the post. There is no beneficial effect on cement delamination of other pretreatment methods compared to no pretreatment of the post.