Polymerizing depth of colorless light-cured resin for abutment built up

Objectives: Recently in case of abutment built up for root treated tooth composite resin is increasingly applied. Chemical-cured composite resin used to be applied for abutment built up; however, lately light-cured composite resin and light and chemical-cured composite resin are begun to apply. When light-cured composite resin was applied for abutment built up, it must be taken into consideration that non-polymerizing layer remains in the internal part of resin. The purpose of this study is to investigate the influence of color in light-cured composite resin on the polymerizing depth.

Methods: As experimental materials, Unifil Flow A2 (UFA2), Unifil Flow A3 (UFA3), Solodex A2B (SA2B), DC Core Automix Dentin (DCD), Unifil Core (UC) and prototype colorless light-cured composite resin (PT) were used. The polymerizing depth of each resin was measured based on ISO standard 4049:2000. Each resin was filled into the column shaped metallic mold with a diameter of 4.0 mm and 15.0 mm deep. The specimens were polymerized with 40 sec light irradiation using light curing apparatus. After light irradiation, the specimen was taken out from the metallic mold and non-polymerizing layer of the specimen was removed with ethanol gauze, then the height of the polymerized specimen was measured with a micrometer. Specimens were prepared five pieces of each experimental resin respectively. The data was analyzed using one-way ANOVA in combination of Tukey's multiple comparison tests.

Results: The polymerizing depth of DCD was 2.37±0.18 mm that showed shallowest value among six experimental resins, while that of PT was 9.69±0.22 mm that showed deepest value among six experimental resins. The polymerizing depth of PT was significantly higher than that of the other five resins.

Conclusion: From the mentioned above, it was suggested that the polymerizing depth of the prototype colorless photo-cured resin was deep compared to the other photo-cured resin.