To Evaluate And Compare Effect Of Different Thickness Of Heat Cured Polymethyl Methacrylate Denture Base Resins Stored In Distil Water And Artificial Saliva At Different Time Intervals On Sorption And Linear Dimensional Change – An In-Vitro Study

To evaluate & compare effect of different thicknesses of heat cure polymethyl methacrylate denture base resin at different time intervals in distilled water, artificial saliva and its combination on sorption and linear dimensional change.- An in- vitro study. Materials & Method: This was an invitro study where a total of 176 samples of heat cured polymethyl methacrylate were made. 44 samples each of 1mm and 2mm rectangular slab and 44 samples of each 1 mm and 2mm circular discs were made. 11 samples were allocated to each group of 1mm and 2 mm samples and immersed in artificial saliva and distil water for 30 and 90 days. The rectangular slabs were used to test the linear dimensional change and the circular discs were used to test for sorption according to ADA specification number 12. Results: Unpaired T test was used to evaluate the values obtained in the study. It was observed that the linear dimensional change seen was statistically significant after immersing the 1mm (p = 0.013) and 2mm (p = 0.019) samples for 30 days in artificial saliva and distil water. No statistically significant change was seen in sorption over 30 and 90 days. Conclusion: The greatest change in linear dimensional change was observed after 30 days in artificial saliva and distil water. No significant changes were seen thereafter in linear dimensional change or sorption. Clinical significance: The thickness of the denture base material is an important factor for successful prosthesis. If the denture base is thin, it may fracture, may not tolerate occlusal forces. If it is thick it will be heavy to load the tissues, may absorb more liquid & shows linear dimensional changes & may not fit the tissues & disturbs the occlusion. Inspite of such an important factor thickness of the denture base is often neglected.