Retention of Co-Cr bars supporting mandibular implant overdenture fabricated with two techniques.

OBJECTIVE: The goal of this study was to see how laser-sintered and regular cobalt-chromium bars affect how well they hold in place and how rough their surfaces are in lower jaw implant overdentures.

MATERIALS AND METHODS: This study utilized a completely edentulous mandible model that was fabricated from epoxy resin. Implants were imbedded in the canine region in the model, then implant abutment were screwed on each implant. Scan bodies were inserted, then scanning of the 3D model was done using a laboratory scanner. CO-CR bars were divided into: Group A: Twelve bars that were fabricated using the laser sintering method. Group B: twelve bars were designed using CAD/CAM for the fabrication of a wax model, and then the bar was fabricated using a conventional lost wax-casting technique. Each bar and implant were loaded with a conventional acrylic resin denture. A universal testing machine was used to apply tensile load. Surface roughness was estimated by using a digital microscope with digital software. The data was collected and analyzed using statistical analysis.

RESULTS: There was a significant difference between group A and group B regarding the technique of fabrication of the implant bar in both retention and surface roughness.

CONCLUSION: changing the technique for fabricating the implant bars has improved the retention and surface roughness of the implant-supported overdenture.