Brushing effect on retentive force and surface roughness of three overdenture attachment patrices: An in vitro study.

Purpose: To investigate the brushing effect on retentive force and surface roughness of titanium, coated titanium, and zirconia patrices in implant-retained overdenture attachments.

Materials and methods: Patrices in three denture attachments (titanium [Mini Ball], coated titanium [LOCATOR], and zirconia [Zeramex Docklocs]) were embedded in resin blocks and brushed for 50,000, 100,000, and 150,000 cycles with toothpaste slurry. The retentive force and surface roughness of both the occlusal and lateral surfaces of each patrix were measured and averaged. Data were analyzed using the 2-way repeated measures ANOVA (α = 0.05).

Results: Significant interactions between attachments and brushing cycles were found for both retentive force and surface roughness (p < 0.001). Zeramex Docklocs exhibited the highest retentive force, while Mini Ball exhibited the lowest. After 150,000 cycles, the retentive force in Mini Ball and LOCATOR was similar (p = 1.00), while Zeramex Docklocs increased significantly (p < 0.001). Zeramex Docklocs had the lowest occlusal surface roughness (p < 0.001), while Mini Ball had the lowest lateral surface roughness (p < 0.001). After 150,000 cycles, the surface roughness on the occlusal surface of Mini Ball decreased (p < 0.001), that of LOCATOR increased (p < 0.001), and Zeramex Docklocs showed no change (p = 1.00). In contrast, the surface roughness on the lateral surface of Mini Ball showed no change (p = 0.139), that of LOCATOR decreased (p < 0.001), and Zeramex Docklocs increased (p = 0.023).

Conclusions: The patrices in each tested denture attachment could provide retention and maintain surface characteristics after stimulated brushing for up to 150,000 cycles.