Future Dental Journal


Purpose: To compare different retentive cap material used in LOCATOR attachments, namely the nylon retentive cap versus PEEK retentive caps, and measure the loss of retention over a period of two years, through 2880 cycles of insertion and removal. Materials and methods: Two implants 3.8mm x 10.5mm were inserted into a clear epoxy resin cast, through a surgical guide, with the implants being 23mm apart. Two LOCATOR attachments with 5 mm gingival height were screwed to the implants, custom made nylon caps were fabricated as an exact replica of the PEEK retentive caps, then two dentures were constructed and pick up were done with both retentive cap materials. A hook was attached to the geometric center of both dentures, and measurement of the retentive forces was accomplished with a universal testing machine, and the data was recorded and analyzed. Results: The amount of retention achieved from PEEK retentive caps was twice that of the nylon retentive caps, indicating high statistical significance (p < 0.001) of the effect of the material and remained so throughout the repeated cycles with (p < 0.001), however both caps showed similar rate of retention loss throughout the study, but the amount of wear was statistically higher in the PEEK group throughout the cycles, except after 2880 cycles. Conclusion: PEEK showed higher retentive properties throughout the cycles, but both materials showed similar rate of retention loss.