Digital Versus Conventional Techniques for Construction of Mandibular Implant Retained Overdenture

Abstract Background: This study aimed to evaluate two different construction techniques (conventional and 3D-printed techniques) for two implant-retained complete mandibular overdentures regarding mechanical wear of the occlusal surface using 3D digital analysis andocclusion force distribution using the digital occlusal analysis system (Occlusense). Methods: Twenty patients were selected for this study from the prosthetic department, Faculty of Dentistry, Mansoura University. The sample size was determined based on the results of previous clinical trial with (effect size = 1.1, α = 0.05, β =0.90). The calculated sample was 20. The power analysis was performed with the aid of computer software (G*power 3.1.5, Heinrich-Heine-Universität Düsseldorf, Germany). Balanced randomization was used to equally assigned patients to one of two groups using to ensure comparability between groups. The participants were randomly assigned into two groups using random numbers generated in an Excel spreadsheet.Each patient received two implants in the mandibular canine areas with locator attachments to retain the overdentures. According to the overdenture construction technique, all patients were classified into two equal groups: the conventional heat polymerized overdenture group and the 3D-printed overdenture group. The mandibular overdentures were compared and evaluated immediately and after 12 months of insertion regarding mechanical wear of the occlusal surface using 3D digital analysis and occlusal force distribution using a digital occlusal analysis system (Occlusense). Results: 3d printed group showed significantly higher occlusal surface wear than conventional group after twelve months (T12) with a p value ≤ 0.05. 3d printed group showed significantly more occlusal force distribution than conventional group with a p value ≤ 0.05. Also, there was a significant difference in occlusal force distribution with advance of time for each group, with a p value ≤0.05 level of a significance. Conclusion: Within the limitations of this study, it was shown that implant overdentures constructed by conventional techniques show superior results regarding mechanical wear of the occlusal surface compared to 3D-printing techniques. However, 3D-printing techniques offer a promising result compared to conventional techniques for the construction of implant overdentures regarding occlusal force distribution. Trial registration: The study was approved by the local ethical committee of the Faculty of Dentistry, Mansoura University (No. A02060922) and retrospectively registered at ClinicalTrials.gov (ClinicalTrials.gov Identifier: NCT06139003 ) (16/11/2023).