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Evaluation of Strength of Different Resin Materials Used in Evaluation of Strength of Different Resin Materials Used in Overdenture

Introduction: Finding a suitable material that could be used to restore relatively small inter-arch spaces in which reasonable aesthetics as well as good functional strength could be achieved is a difficult process that requires good understanding of the clinical situation and precise management. Historically Metal used to offer the smallest possible thickness with excellent strength but lacks resiliency with poor aesthetics. Aim of the study: This In-vitro study was conducted to compare two different aesthetic materials PEEK and ACETAL regarding their mechanical strength when used as Overdenture framework in a relatively small thickness. Material and Methods: 120 specimens were prepared according to the American Society for Testing and Materials (ASTM) International standards and divided into two main groups according to the material, group (A) PEEK samples and group (B) ACETAL samples. Each group of 60 specimens was subdivided into three different groups (I, II, III) according to three different thicknesses (1, 1.5 and 2 mm). Each group contains 20 identical samples, half of them were subjected to water absorption and the other half were left untouched. Then all specimens were loaded to failure in a Universal Testing Machine (UTM). Results: Data analyzed using Student’s t test for independent samples and showed that any increase in thickness lead to increase in the flexural strength which was proportioned in all Acetal samples in contrast to PEEK samples. All PEEK samples recorded significantly higher flexural strength values on every thickness than Acetal samples. Acetal samples with 2 mm of thickness did not offer enough strength as suggested by the international standards for polymer materials and ISO. Conclusions: The flexural strength of PEEK samples was 3 times higher than Acetal samples. Acetal thickness should be more than 2mm. water has a significant effect on the strength of Acetal materials