The influence of bis-EMA content on the leachability of dental composite resins

Abstract

Objective: Composite resin based materials (CRM) are widely used in dentistry for its aesthetics and ability to preserve tooth structure. The main ingredients are monomers that during polymerization undergo crosslinking to form the resin matrix, bonding the material together. However, not all the monomers will react during polymerization, and remain in the matrix as free residual compounds that can elute. This is of clinical importance as monomers and their degradation products are known to cause allergic reactions, and there are concerns regarding the potential toxic effects of these eluted compounds. The objective of this study was to investigate how different ratios of bis-GMA versus bis-EMA relative to each other would influence the leakage of TEGDMA from the composite. Materials and methods: Storage solutions of experimental composites with known concentrations of bis-EMA, bis- GMA, TEGDMA and UDMA were used, with storage time 24 h, 7 days and 30 days. Three randomly collected solution samples from each group (n=36) and time interval was chosen. The analysis was performed by using GC-MS. Results: TEGDMA was detected in all samples. The results showed a trend where the group containing the most bis-EMA eluted less than the groups containing bis-GMA at the time intervals studied. Conclusions: Within the limitations of the present study the following conclusions were drawn: A trend was shown toward less leakage from the composite containing the most bis-EMA compared with the composites containing bis-GMA at the time intervals studied. The null hypothesis was therefore considered as rejected. Leakage of TEGDMA was found for all composites tested, however the quantification was uncertain. More research on the subject is needed to determine if there is a significant difference.