Comparison of Retention Between Different Duplication Techniques: Conventional Versus CAD/CAM: A Within Subject Controlled Clinical Trial

This study aimed to compare retention and occlusal force distribution between conventional and two three-dimensional (3D) printed computer-aided design and computer-aided manufacturing (CAD/CAM) duplication techniques for refitted maxillary complete dentures. Twenty completely edentulous individuals with preexisting complete dentures participated in this within-subject controlled clinical trial. Dentures were duplicated using three methods: Group I (conventional duplication), Group II (3D printing to create a separate base made of pink polymethyl methacrylate (PMMA) and teeth made of tooth-colored PMMA teeth), and Group III (3D printing of a single unit denture with a veneered base made of pink photo-curable resin). Occlusal force distribution was measured for the reference denture before duplication. Retention and occlusal force distribution were measured at the time of denture insertion. A one-way analysis of variance (ANOVA) was used for group comparisons, and Bonferroni's post hoc test was utilized for multiple comparisons. The highest mean retention was observed in Group II (36.53±3.75), followed by Group III (35.01±3.41) and Group I (27.95±4.32) with a statistically significant difference between Group I and the other two Groups. For occlusal force distribution, the highest mean difference was recorded in Group I (14.35±3.25), followed by Group II (7.60±1.84) and Group III (3.82±0.91) in comparison to the reference denture with a statistically significant difference (P=0.001). Within the study's limitations, 3D-printed dentures showed superior retention and more balanced occlusal force distribution compared to conventional methods. These findings imply that 3D printing technology may improve prosthodontics' ability to construct duplicate dentures.