Five years follow-up of mandibular 2-implant overdentures on locator or ball abutments: Implant results, patient-related outcome, and prosthetic aftercare

Background: It is uncertain, which is the optimal attachment for a mandibular 2-implant overdenture (2IOD).

Purpose: To assess 5 years clinical implant outcome, prosthetic maintenance, cost, and PROMs of two cohorts receiving 2IOD on ball or stud abutments in a comparative study.

Materials and methods: Ninety edentulous individuals were treated with balls (n = 34) or locator (n = 56). Implant survival, bone-to-implant level, prosthetic outcome, technical maintenance, and OHIP-14 were assessed. Statistics to compare between baseline and 1/5 years and between groups were t-test or Mann-Whitney (P < .05); chi-square was adopted to analyze plaque and technical maintenance or interventions between groups.

Results: Five years implant survival was 98.7%, irrespective of attachment. Overall mean bone loss was 1.1 mm, probing pocket depth 1.92 mm, bleeding score 0.60, plaque score 1. Plaque accumulated more on locators (P = .023). OHIP-14 declined from 18.1 to 2.7 irrespective of attachment. Retention for balls was better (P < .005), locators required more maintenance (P < .001), caused by retention-adjustment (P < .001) or ulcers/pain (P = .014). Five years maintenance-cost was 11% of initial cost, irrespective of attachment.

Conclusions: Balls and locators yield stable 5-years implant outcome and improved Oral Health Related Quality of Life (OHRQoL). Locators required more maintenance and resulted in a lower retention. Maintenance costs are minimal but may affect OHRQoL at least for stud abutments.