Immediate/early function with tapered implants supporting maxillary and mandibular posterior fixed partial dentures: preliminary results of a prospective multicenter study.

Statement Of Problem: While immediate loading in the interforaminal area of the mandible is a documented procedure, there are limited scientific data for immediate/early loading in premolar and molar areas where less bone density is often found and functional loading is high.

Purpose: The purpose of this study was to evaluate if there is a difference between immediate and early loading in premolar and molar areas of the mandible and maxilla and compare data to historic data.

Material And Methods: Fifty-one patients received 120 tapered implants in premolar and molar areas of the mandible and maxilla, for a total of 54 short-span (2 to 4 units) fixed partial dentures. Patients with noncontrolled diseases, periodontal pathology, bruxism, and heavy smokers (more than 10 cigarettes a day) were excluded. Patients were divided into 2 groups, with placement of provisional fixed partial prostheses occurring within 24 hours (n=33) or 6 weeks (n=21) after implant surgery. The provisional prostheses had narrow, flat occlusal surfaces to reduce lateral contacts. Surgery was performed with flap elevation, a surgical guide was used, and sites with bone with lower density were underprepared. Implant insertion torque values were between 35 and 45 Ncm. After 6 months, definitive metal-ceramic prostheses were placed. Patients were monitored clinically and radiographically for marginal bone remodeling at baseline, and 3, 6, and 12 months after loading. All patients were followed for 1 year. Data were analyzed with descriptive statistics.

Results: No implant failure occurred. Mean marginal bone resorption (SD) was 1.24 (0.88) mm for the immediate loading group and 1.19 (1.01) mm for the early loading group after 1 year.

Conclusions: The preliminary results demonstrate that if accurate surgical and prosthetic protocols are followed, immediate and early function are predictable and safe approaches even in premolar and molar areas with low bone density.