Implant Success in Sinus-Lifted Maxillae and Native Bone: A 3-year Clinical and Computerized Tomographic Follow-up

Purpose: The present study was a 3-year follow-up evaluation of implant clinical success and radio-graphic bone remodeling in sinus floors elevated with different autogenous bone-grafting procedures and in similar native bone regions. Materials and Methods: This retrospective chart review examined consecutive edentulous patients with severe jaw atrophy treated between 2000 and 2002 via sinus lift, when needed, and implant insertion. Implants in sinus lift areas were divided into four groups by graft source (iliac crest, chin area) and technique (bone block, particulate). Implants positioned in native areas beneath the sinus floor served as controls. The cumulative success rate (CSR) and success rate (SR) were calculated, and linear measurements of bone remodeling around implants were assessed on computerized tomographic scans. Results were statistically compared with the Wilcoxon signed rank test. Results: Twenty-eight patients were treated in the posterior maxilla via insertion of 70 screw-type, root-form, rough implants in 39 sinus-lifted areas. All surgical procedures were uneventful. Twenty-four implants were positioned in native areas beneath the sinus floor. The implant CSR was 95.8% in native areas (one failure/24 implants), 85% in sinuses lifted with particulate chin bone (three failures/20 implants), and 100% in the other three groups (eight in particulate iliac crest, 20 in chin block, and 22 in iliac crest block). Computerized tomographic scans revealed that bone remodeling around apices caused implants to bulge into the sinuses in both particulate bone graft groups. Crestal remodeling around implant necks was similar for all groups. Conclusions: The use of particulate chin bone grafts in sinus lift procedures does not seem to yield optimal outcomes. Milled iliac crest and chin bone tends to remodel around the implant apices, leading to bulging within the sinuses. Grafting sinuses with either chin or iliac crest bone blocks yields the highest implant success rates and stable sinus floors. Keywords: atrophic maxilla, autogenous bone graft, dental implants, osseointegration, sinus lift