Long-term degradation of resin-based cements in substances present in the oral environment: influence of activation mode

Eduardo Moreira da SILVA,Laiza Tatiana POSKUS,Jose Guilherme Antunes GUIMARAES,Cristiane Mariote AMARAL,Jaime Dutra NORONHA-FILHO

doi:10.1590/1679-775720130026

Eduardo Moreira da SILVA, Laiza Tatiana POSKUS + Show 3 more

Open Access

https://doi.org/10.1590/1679-775720130026

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Abstract

Indirect restorations in contact with free gingival margins or principally within the gingival sulcus, where the presence of organic acids produced by oral biofilm is higher, may present faster degradation of the resin-based cement pellicle.Objectives:To investigate the degradation of four resin-based cements: Rely X ARC (R), Variolink II (V), enforce (E) and All Cem (A), after immersion in distilled water (DW), lactic acid (LA) and artificial saliva (AS) and to analyze the influence of the activation mode on this response.Material and Methods:Two activation modes were evaluated: chemical (Ch) and dual (D). In the dual activation, a two-millimeter thick ceramic disk (IPS empress System) was interposed between the specimen and light-curing unit tip. Specimens were desiccated, immersed in distilled water, artificial saliva and lactic acid 0.1 M at 37ºC for 180 days, weighed daily for the first 7 days, and after 14, 21, 28, 90 and 180 days and were desiccated again. Sorption and solubility (µg/mm3) were calculated based on ISO 4049. The data were submitted to multifactor analysis of variance (MANOVA) and Tukey's HSD test for media comparisons (α=0.05).Results:Sorption was higher after immersion in LA (p<0.05) and increased significantly with time (p<0.05). Sorption was influenced by the activation mode: Ch>D (p<0.05). The lowest solubility was presented by R (p<0.05). Conclusions:Lactic acid increased the degradation of resin-based cements. Moreover, the physical component of activation, i.e., light-activation, contributed to a low degradation of resin-based cements.

Highlights

In state-of-the-art restorative dentistry, there has EHHQ D VLJQL¿FDQW LQFUHDVH LQ WKH GHYHORSPHQW DQG use of ceramic materials for esthetic restorations
Until now, little information has been available about resin-based cement degradation in the substances present in the oral environment18. ,Q WKLV ¿HOG VRPH SXEOLVKHG VWXGLHV KDYH VKRZQ that the durability of the bond between resin-based cements and dentin can be affected by water immersion and over the course of time7,13
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Summary

Introduction

In state-of-the-art restorative dentistry, there has EHHQ D VLJQL¿FDQW LQFUHDVH LQ WKH GHYHORSPHQW DQG use of ceramic materials for esthetic restorations. In indirect restorations in anterior teeth, the cervical margins of ceramic restorations are often located close to the free gingival margin or even within the gingival sulcus. Resin-based cements are basically constituted from photo-initiator substances, pigments, small DPRXQWV RI ¿OOHU SDUWLFOHV DQG PDLQO\ PHWKDFU\ODWH monomers such as Bis-GMA, UDMA and TEGDMA. Their polymerization mechanism involves a free radical polymerization reaction, which leads to a viscoelastic transformation into a rigid stage

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