The aim of this study was examining the impact of various telescopic crown attachment materials on implant-retained mandibular overdentures' retention.
Material and Methods: completely edentulous mandibular epoxy models were constructed; wherein various material combinations have been used for constructing telescopic attachments for two implants placed in the canine area. The traditional standardized method was used to fabricate thirty-three identical mandibular overdentures. Based on the material utilized in constructing the secondary coping, the study groups were divided into three categories: PEEK/PEEK, PEEK/ZrO2, and PEEK/CoCr. For each research group, primary PEEK copings were created. On a prefabricated abutment, primary copings were cemented in place. In the intended insertion path, secondary copings were positioned over the primary copings and then lifted up into the overdentures' intaglio surface. In order to assess each group's retention value, a vertical load of 100 N was adjusted in the universal testing machine. Insertion-removal cycles were applied repeatedly using a cyclic loading machine to simulate nearly 10 years of clinical use.
Results: The mean retention values for PEEK-PEEK, PEEK-ZrO2, and PEEK-CoCr groups varied from 2.19 to 1.16 N, 5.78 to 2.51 N, and 1.15 to 0.31 N, respectively. The retention varied statistically significantly throughout the study groups. PEEK/PEEK recorded the highest retention value, followed by PEEK/ZrO2 and PEEK/CoCr, respectively.
Conclusions: The telescopic crown materials have an impact on the retention forces, even in cases when the identical crown design is selected. Within the limitations of this investigation, the combination of PEEK-PEEK, followed by PEEK-ZrO2, demonstrated superior retention results.