Evaluation of Polymerization Shrinkage and Depth of Cure of Silorane Based Composite Resin and Methacrylate Based Composite Resin (Comparative Study)

Abstract

Background and objectives: composite constitutes the majority of the direct tooth colored restorations that replace the biological tissue. The major drawbacks of composite resins are related to polymerization shrinkage. This study aimed to compare the polymerization shrinkage and depth of cure between different types of composite resins. Materials and methods: fifteen premolar teeth for each group were collected and cavities prepared on the buccal surface to the depth of 1.5 mm with 3 mm using a diamond cylindrical bur with water coolant. Then each fifteen cavities were filled with one type of composite resin according to the manufacturing instructions. After that specimens were stored in deionized water for one week. Subsequently, the marginal gaps were observed and measured by using a light microscope with a reticular measuring ocular. For the depth of cure Fifteen samples for each group were prepared using metal molds with 6 mm thickness and 4 mm in diameter The composite materials were light cured, then the specimen removed from the mold and the uncured material gently removed with the plastic spatula, the height of cured material was measured with a micrometer and the values were divided by 2, this value was recorded as a depth of cure. Results: The descriptive statistics for the degree of polymerization shrinkage among three groups cleared that the P90 showed the lowest value for polymerization shrinkage with significant difference among three groups. For the depth of cure, it was clear that the Sigma methacrylate based composite resin showed the highest value with significant difference among three groups. Conclusion: Silorane based composite resin produced less polymerization shrinkage in comparison with methacrylate composites resin. The Depth of cure of Sigma methacrylate based composite resin is more in comparison silorane based composite resin.