Purpose:evaluate three-dimensional marginal bone loss around implants supporting metal ceramic and metal acrylic screw retained hybrid prosthesis for rehabilitation of atrophied mandible using (CBCT) after one year.
Materials and methods: Ten completely edentulous patients with mandibular ridge atrophy were randomly assigned into 2 groups; Group I; included 5 patients who received Metal ceramic screw retained hybrid prosthesis, Group II; included 5 patients who received Metal acrylic screw retained hybrid prosthesis. All patients then received 4 implants in the inter-foraminal area of the mandible using the flapless surgical approach. After osteointegration, implants were loaded by the prostheses with a distal cantilever not exceed 1.5 antro-posterior spread. Vertical and horizontal bone resorption was assessed at mesial, distal, buccal and lingual aspect of anterior and posterior implants using (CBCT) at time of prosthesis insertion (baseline), 6 months and one year later.
Results: After 6 and 12 months, metal ceramic prosthesis showed significant higher vertical and horizontal bone resorption than metal acrylic prosthesis for anterior and posterior implants. Posterior implants showed significant higher vertical and horizontal bone resorption than anterior implants for metal ceramic group only and no difference in bone loss between anterior and posterior implants in metal acrylic group was noted. For both groups and implant positions, vertical and horizontal bone resorption at 12 months significantly increased compared to 6 months
Conclusion: metal acrylic cantilevered prosthesis for screw retained hybrid restoration of edentulous atrophied mandible may be recommended than metal ceramic prosthesis