Effect of Denture Base Material on the Peri-implant Stresses of Implant Supported Overdenture: An In Vitro Study

Purpose: The purpose of this study was to evaluate the effect of denture base material on the peri-implant stresses of overdentures held in place by inclined and straight implants during axial dislodgments. Materials and methods: Four heat-polymerized polymethylmethacrylate (PMMA) resin edentulous mandibular overdenture models were divided with respect to their denture base material and angulation of the implants in bilateral canine region in all four groups: group I (model with two parallel implant-supported PMMA overdentures), group II (model with two parallel implant-supported thermoplastic nylon overdentures), group III (master model with two inclined implant-supported PMMA overdentures) and group IV (master model with two inclined implant-supported nylon overdentures). All overdentures were secured with a ball and socket attachment and connected with strain gauges placed around implants. The stresses were measured under a 100N compressive load using an eight-channel strainometer linked to a universal testing machine. Student <i>t</i>-test was done for comparison between two study groups, and a one-way analysis of variance (ANOVA) was used for comparison of stresses at different implant sites in each group. Results: Straight implants experience higher levels of stresses in PMMA overdenture (group I) than nylon overdenture (group II) at all sides, and the difference was statistically significant. Inclined implants experience higher levels of stresses in PMMA overdenture (group III) than nylon overdenture (group IV) at all sides, and the difference was statistically significant at all sides except mesial side (<i>p</i> = 0.145). Inclined implants (group III) experience higher levels of stresses than straight implants (group I) at all sides with both PMMA and nylon overdentures. Conclusion: Peri-implant stresses were more with PMMA overdentures compared to nylon overdentures on both straight and inclined implants. Nylon overdentures with straight or inclined implants can be given as it generates less stresses compared to PMMA overdentures. How to cite this article: Bassiouny HM, Atito EM, Badr WE, <i>et al.</i> Effect of Denture Base Material on the Peri-implant Stresses of Implant Supported Overdenture: An <i>In Vitro</i> Study. Int J Prosthodont Restor Dent 2024;14(3):135–139.