The effect of clip material on the retention of implant retained mandibular overdenture: randomized clinical study

Abstract Aim To evaluate the retention of implant retained mandibular overdenture with polyether-ether-ketone (PEEK) bar using either ready-made nylon clips or custom-made PEEK clips over a one-year randomized clinical study. Materials and methods Twenty completely edentulous patients received two implants inserted bilaterally in the canine-premolar region. A milled PEEK bar was screwed to the multiunit abutment screwed to the implants. Patients were divided equally into two groups ( n = 10) according to clip material; group1: ready-made nylon clip and group 2; PEEK clip (Pressed BioHPP®). Clips were picked up into the fitting surface of the overdenture. Retention force was measured at insertion, three months, six months and one year using universal testing machine. Data were analysed using two-way repeated measure ANOVA followed by Bonferroni post-hoc tests ( p ≤ 0.5). Results Retention values between nylon clip group and PEEK group revealed non-statistically significant difference at insertion (28.98 N ± 3.40 and 28.38 N ± 4.80 respectively), three months (30.93 N ± 3.52 and 30.43 N ± 4.7 respectively), six months (30.63 N ± 3.50 and 30.48 N ± 4.63 respectively) and one year (27.13 N ± 3.38 and 27.69 N ± 4.41 respectively). Conclusion PEEK clips used for retention of PEEK bar-implant retained mandibular overdentures showed comparable retention values to nylon clips up to one year.