PEEK vs Metal Bar Attachments

This randomized, parallel-group clinical trial evaluates the clinical performance of CAD/CAM-fabricated PEEK bars compared with traditional metal bars for retaining mandibular single overdentures supported by two implants. The study includes 20 fully edentulous mandibular patients aged 40-70 years who report functional difficulties with a single lower denture. All participants undergo placement of two dental implants in the mandibular canine regions using a two-stage surgical protocol. After osseointegration, patients are randomly assigned to one of two groups: PEEK bar group: overdentures retained using a digitally designed and milled PEEK bar. Metal bar group: overdentures retained using a conventional metal alloy bar. The scientific rationale for evaluating PEEK is based on its lower elastic modulus, which may allow more favorable stress distribution to peri-implant bone compared with the higher stiffness of metal bars. This biomechanical difference may influence implant survival, marginal bone remodeling, and perceived comfort. Clinical outcomes are assessed at insertion and at 3, 6, 9, and 12 months. Marginal bone loss is measured radiographically using standardized periapical images. Patient-reported satisfaction is captured using a validated Visual Analogue Scale across major functional domains. The statistical approach uses Aligned Rank Transform ANOVA due to non-normal data distribution, with Tukey post-hoc testing for pairwise comparison. This trial contributes new data on material selection for bar attachments in implant-retained mandibular overdentures. The findings suggest that PEEK bars may offer biomechanical advantages by reducing bone loss while maintaining patient satisfaction comparable to metal bars. Further long-term studies with larger sample sizes are recommended to validate these results and support broader clinical adoption.