Purpose: Compare three-dimensional marginal bone loss around implants supporting fixed metal-ceramic prosthesis and implant overdentures in patients with mandibular edentulous ridges.
Materials and methods: Twelve completely edentulous patients were randomly assigned into two groups; 1) Group A (fixed prosthesis); patients received 6 implants (4 in the interforaminal area, and 2 posterior to the mental foramina) and fixed full arch screw-retained porcelain fused to metal restoration, 2) Group B (overdenture prosthesis); patients received four implants in the interforaminal area and the implants were connected to overdentures with locator attachments. For each participant, Three-Dimensional bone loss was measured at mesial, distal, buccal and lingual surface of each implants using (CBCT) which was made at time of prosthesis insertion, 1year, and 3years after insertion


Results: For all implant surfaces except lingual, overdenture group showed significantly higher marginal bone loss than fixed prosthesis after one years and 3 years. For fixed prosthesis group,

Highest bone resorption after one and 3 years was observed in the lingual site and the lowest marginal bone loss was observed at buccal site. For overdenture group, the highest bone loss observed at the buccal site, and the lowest one loss was observed at lingual site (after 1year) and distal site (after 3years). For both groups, bone loss after 3 years was significantly higher than after one year.
Conclusion: Within the limits of this randomized controlled study, fixed prosthesis was associated with reduced Three-Dimensional marginal bone loss compared to overdentures prosthesis after one and three years of prosthesis insertion.