Inhibition Layers by Radical Polymerized Luting Materials

Objectives: The inhibition layer of luting materials is in general an underestimated topic in the field of dentistry. In this study, different luting materials was compared in order to emphasize the importance for the use of an inhibition avoiding gel which is essential for a long term stability of the margins.

Objective: Comparison of the inhibition layer of Variolink-Esthetic (VAE-Ivoclarvivadent), Variolink-II (VII-Ivoclarvivadent), Multilink-Automix (MLA-Ivoclarvivadent), RelyX-Ultimate (RXL-3M/ESPE), RelyX-Unicem-2 (RXU-3M/ESPE), Calibra-Ceram (CAC-Dentsply), Nexus3 (NXU-Kerr) and Maxcem-Elite (MCE-Kerr) at the more important self-curing mode.
Methods: On a glass plate 0.10g of luting material was applied within two metal foils with a thickness of 0.08mm. The metal foils were used as a spacer. A drop of glycerine gel was applied to one side of the luting material. With a second glass plate the sample was covered and loaded with 120g for 30minutes at the self-curing mode. The barrier within the luting material, glycerine gel as well as air was evaluated using an optical microscope. In addition, the inhibition layer could be successfully measured (n=5) at the airside and statistically analyzed (ANOVA, Tukey's, p<0.05).
Results: The inhibition layer with more than 200µm showed to be significantly higher than it is described in the literature with only showing approximate 100µm. In general, all luting materials showed a similar inhibition layer. No statistical difference could be detected.
Conclusions: The inhibition layer for all luting materials showed to be highly similar. There was no dependent relationship observed between the different initiator systems by the different products as long as there is a radical polymerisable system applied. Of high interest is that the inhibition layer for the self-curing mode showed to be much higher than described in the current literature.