Original Research Article Effect of Radiotherapy on Flexural Strength of Luting Cementsan In Vitro Study

Aim - The aim of this study was to evaluate changes in the flexural strength of luting cements due to radiotherapy. Methodology- 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 included 30 specimens made of zinc phosphate cement, Group B included 30 specimens fabricated using glass ionomer luting cement, and Group C consisted of 30 specimen’s fabricated using resin luting cement. Once the specimens were set, they were stored in distilled water between the experiments. After 24 hours, 15 from each group of the mentioned cements were subjected to irradiation fractionally 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. All the specimens were subjected to 3 point bend test on universal testing machine for checking flexural strength. Statistics- Kruskal Wallis Test followed by Mann Whitney test as post hoc analysis 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 glass ionomer luting cement (Group-B), showed a slight decrease in flexural strength. The resin luting cement (Group-C) showed slight increase in flexural strength. Conclusion- Among all the groups, the resin luting cement showed a slight increase in flexural strength when compared to the other luting cement groups after fractional irradiation