A New Resin Composition for Sealing Dental Composite

Objectives:Previous studies have shown that resin composites are susceptible to staining in various media. Staining susceptibility of resin composites is attributed to their degree of water sorption and hydrophilicity of the resin matrix. Extra water sorption may also decrease the life of resin composites by expanding and plasticizing the resin component, hydrolyzing the silane and causing micro-crack formation. A way to prevent water sorption is to apply a glazing system . The Aim of the study was to develop a glazing system that protects the composite resin from water sorption by using more hydrophobic resins.

Materials and Methods: A derivative of Bis-GMA was synthesized by replacing the hydroxyl groups with methoxy groups. The new resin, Bis GMA , UDMA and EBPADMA were used as base resins and mixed with TEGDMA, camphorquinone and DMAEMA to make finishing glazing systems. Twenty five resin samples were prepared according to ADA #27 specification. Samples were randomly divided in 5 groups and each group was coated with one glazing systems or no glaze. Sorption and solubility tests were done according to ADA #27 and results were analyzed using one way ANOVA.

Results: Significant differences were detected among groups both for water sorption (p=0.005) and water solubility (p<0.001). Methoxy BisGMA + TEGDMA (13.4 µg/mm3) showed the least and BisGMA+TEGDMA (16.871 µg/mm3) the most water sorption. Regarding water solubility BisGMA+TEGDMA (7.8 µg/mm3) and UDMA + TEGDMA showed the most solubility.

Conclusion: The New Methoxy Bis-GMA is very promising to be used as a main resin for composite surface sealants or glazing systems. Improvements are needed to replace the diluting resin.