Stress free versus Hader bars for immediately loaded two-implant retained mandibular overdentures. A one-year randomized trial evaluating marginal bone loss and patient satisfaction

Objectives: The aim of this study was to compare marginal bone loss and patient satisfaction with stress free implant bar (SFI bar) and Hader bar used for immediately loaded two-implant retained mandibular overdentures
Material and methods: Ten edentulous patients with conventional mandibular dentures due to atrophied mandibular ridge were randomly assigned to 2 groups and received new conventional dentures. After 2-month adaptation period, 2 implants were inserted in the canine regions of the mandible using computer guided surgery and the flapless approach. Implants were connected with Hader bar (group 1) or SFI bar (group 2) and were loaded by mandibular overdentures within 3 days after implant placement. Marginal bone loss was evaluated at baseline, 6, and 12 months later using cone beam CT. Patient satisfaction with conventional dentures and implant overdentures was measured using questionnaire based on visual analogue scale (VAS)
Results: Marginal bone loss increased significantly from 6months to 12 months for both groups. Hader bar showed significant higher bone loss than SFI bar after 6 months (p=.001) and 12 months (p<.001). For both groups, implant overdentures recorded significant higher satisfaction for tested parameters (except ease of cleaning) compared to conventional dentures. SFI bar recorded significant higher satisfaction compared to natural dentition, satisfaction with retention, stability, ease of cleaning, ease of chewing than Hader bar.
Conclusion: Within the limitations of this study, SFI bar is a beneficial attachment for immediately loaded 2-implant retained overdenture was associated with reduced marginal bone loss and increased patient satisfaction compared to Hader bar.