Evaluation of Physical Properties and Surface Degradation of Self-adhesive Resin Cements

Abstract

This study sought to evaluate the pH value, film thickness, filler particle percentage, and morphological changes of selfadhesive resin luting cements. Products tested were G-Cem, Maxcem, Smart Cem, and RelyX™ Unicem. Cement pH was measured with pH test paper. Filler particle percentage was calculated after cement samples were incinerated at 750℃. To test film thickness, mixed cements were placed between two glass plates and compressed using a loading device. For morphological changes, specimen surfaces were observed by SEM after treatment with various media. There were significant differences among the cement pH values measured at 20 seconds after light curing, and at 90 seconds and 48 hours after mixing. Filler particle percentage was directly proportional to film thickness. Degradation of cement surfaces was also detected after surface polishing and immersion in water, acetic acid, and acetone. In conclusion, significant differences were found in the surface properties of the materials tested, and these differences might lead to differences in their clinical performance.

Are self-adhesive resin cements a valid alternative to conventional resin cements? A laboratory study of the long-term bond strength

“…In this study, RXU revealed significantly less shrinkage strains when self-cured compared to dual-cured setting. In the study by Han [22] , the pH value for RXU was 7.0 48 hours after cementation, while GCM (pH 3.6) and SMC (pH 4.0) maintained in a significant lower pH level. Similar results have been shown in a study by Saskalauskaite [26].…”

“…At conventional resin cements during dentin pre-treatment the dentin tubules are opened and a hybrid layer with resin tags into the dentin can be observed [10] or the smear layer is merely altered and the intertubular collagen only mild demineralised by the bonding agent as in the control group PAN [10]. Measurements of pH values of RXU and GCM after light curing showed values of 5.0 or less [22]. Therefore this cements seem to have technically a potential of decalcification of the dentin.…”

“…In addition, pretreatment of the dentin facilitates to create a real hybrid layer which occurred with PAN but not with RXU [4]. Furthermore, differences in shrinkage behaviour [24], physical properties [25,26], pH values, and film thickness [22] of different self-adhesive resin cements were shown in a number of studies. In a study by Kitzmüller [24], shrinkage behaviour was depended on the temperature of the cement and the curing mode.…”

“…This can be explained by the differences of the self-adhesive resin cements concerning the viscosity or the weight percentage of cement particles. The study of Han [22] showed that there are significant differences in the particle content between GCM and RXU or SMC. An increase of particle content results in an increase of viscosity.…”

Durability of the adhesive cementation to the dentin substract

“…Acid materials retain some degree of hydrophilicity that leaves them prone to capture water, expand and degrade their structural matrices 14 . For cements RelyXUnicem and G-Cem, a work published by Han et al 15 confirm an increase in their pH within 48h following photoactivation.…”