Khyber Medical University Journal (Sep 2022)
EFFECT OF IMMERSION AND INCORPORATION OF POLYVINYL CHLORIDE ON THE FLEXURE STRENGTH AND MICRO HARDNESS OF POLY METHYLACRYLATE DENTURE BASE RESIN
Abstract
OBJECTIVE: To find the effect of artificial saliva, water and different percentages of polyvinyl chloride (PVC) on the flexural strength and microhardness of heat cure polymethylmethacrylate (HC-PMMA) denture base resin. METHODS: An in-vitro study conducted, from April-December, 2020, at the MRL University of Peshawar and Interdisciplinary Research Centre in Biomedical Materials (COMSATS) Lahore. Total of 100 specimens for five groups (n=20) denoted by A, B, C, D and E containing 0%, 5%, 10%, 15% and 20% PVC in HC-PMMA respectively were fabricated to test flexural strength. Each group was divided into two subgroups depending on immersion medium containing ten specimens each. Three-point bending test was used to determine flexural strength. Microhardness was determined using thirty (n=30) specimens through Vickers hardness tester. Statistical analysis was performed by using one way ANOVA and post hoc Tukey test. P-value <0.05 was considered as significant. RESULTS: After immersion in water, one way ANOVA showed significant effect on flexural strength and Post-hoc Tukey’s test showed significant difference between group C and E (p<0.001) and, D and E (p< 0.001). Microhardness of A was significantly different from E after immersion in water (p<.05). Similarly, after immersion in artificial saliva, one way ANOVA showed statistically significant effect on microhardness (p< 0 .01) and Post-hoc Tukey’s test showed significant difference between group C and E (p<0.01) and, A and C (p<0.01). CONCLUSION: Flexural strength of HC-PMMA impregnated with 20% PVC increased after immersion in water, similarly, HC-PMMA containing 10% PVC shows increased microhardness after immersion in artificial saliva.
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