Comparison of peri-implant bone level in mandibular implant overdenture retained by locator attachment with varying retentive insert materials: A retrospective study

Aim: To compare the effect of nylon versus polyetheretherketone (PEEK) retentive insert of locator attachments on peri-implant bone loss in mandibular implant overdenture. Materials and methods: Completely edentulous patients, with two implants locator attachment for mandibular overdenture were recalled for this study. Patients were divided into two groups: Group I: overdenture retained by locator attachment using nylon retentive male insert, and Group II: overdenture retained by locator attachment with PEEK retentive male insert. Digital periapical radiographs were conducted to capture images of dental implants using a long-cone paralleling technique. Images taken immediately (baseline) and 24 months after loading were used for this study to measure the vertical bone loss (VBL) and horizontal bone loss (HBL). It was considered statistically significant when P value was less than 0.05. Results: Twenty-four dental implants were placed in twelve patients aged between 52 and 65 years, comprising 7 men and 5 women. There were no instances of implant loss in either group from the time of placement through prosthetic delivery up to the two-year follow-up period. Group I recorded significant lower VBL than Group II after 24 months of loading (P < 0.05). On the other hand, there was no significant differences in HBL between the two groups (P > 0.05). Conclusion: Implant overdentures retained by PEEK insert did cause more peri-implant bone loss when compared to those retained with nylon inserts; however further studies are needed to validate these results.