Thermocycling Effect on Implant Supported Overdenture Using 3D printed Peek Bar following all-on-4 Concept: Randomized Trial-In vitro Study

Abstract

Objective: Stress analysis and retention evaluation of implant-retained mandibular complete overdenture with different clip materials and distributions. Methods: This in-vitro study was conducted over implants retained mandibular complete overdenture (all-on-4 concept) using BIOHPP bar attachments constructed using 3 D printing with different clip materials and distributions. This study consisted of 4 groups according to the type and distribution of clips: Group I: hard clips anteriorly and posteriorly, Group II: soft clips anteriorly and posteriorly, Group III: hard clips anteriorly and soft clips posteriorly, and Group IV: soft clips anteriorly and hard clips posteriorly. Stress analysis and retention were evaluated before and thermocycling afterward. Results: Comparison between stresses in each group before and after thermocycling in central and peripheral implants was performed, revealing stresses in all groups after thermocycling were significantly higher than before thermocycling as P < 0.05. Regarding retention, a comparison between all groups revealed a significant difference between them before and after thermocycling as P<0.05. Conclusion: There is no effect of clip material distribution regarding stress analysis and retention before and after thermocycling except stresses in central implant before thermocycling as soft clips anteriorly and hard clips posteriorly revealed significant lower stresses than hard clips anteriorly and soft clips posteriorly.