Effect Of Radiotherapy On Modulus Of Elasticity Of Luting Cements- An In Vitro Study

Abstract

Aim- The aim of the study was to evaluate changes in modulus of elasticity of luting cements due to radiotherapy. Materials and Methods- Total of 90 rectangular specimens of 25×2×2 mm dimension were fabricated by utilizing the putty consistency polyvinyl siloxane rubber mould. They were grouped based on their type. Group A had 30 specimens made of zinc phosphate luting cement, Group B had 30 specimens fabricated using glass ionomer luting cement, and Group C had 30 specimens fabricated using resin luting cement. After 24 hours of storing the specimens in distil water, 15 from each group of the mentioned cements were subjected to fractional irradiation upto 60 Gy by a Cobalt-60 external beam machine. Remaining specimens from each group were used as controls. After radiotherapy, the specimens were stored in distil water for 24 hours until performing the 3 point bend test. Flexural strength values were obtained, using which modulus of elasticity of each specimen was assessed. Statistical Examination- Kruskal Wallis Test followed by Mann Whitney test was used to compare the mean values of different parameters between three groups of Irradiated and controlled samples. The level of significance was set at P<0.05. Results- After exposure to fractional irradiation for 4 weeks, in the zinc phosphate luting cement (Group-A) and resin luting cement (Group-C) showed a increase in modulus of elasticity. The glass ionomer luting cement (Group-B), showed decrease in modulus of elasticity. Conclusion- Among all, resin and zinc phosphate luting cement showed increase in flexural strength when compared to glass ionomer cement after fractional irradiation.