Purpose: This article provides preliminary clinical results on the Osseotite NT implant, which was developed to simplify surgical procedure and cover an extended range of indications. Placement characteristics of NT and standard Osseotite implants were also compared in an in vitro study. Materials and Methods: The in vitro placement characteristics of NT and standard Osseotite implants of 4.0 mm diameter and 8.5 to 15 mm in length were compared. In addition, a total of 182 NT implants (96 maxillary and 86 mandibular) were placed in 92 patients; of these, 87.9% were placed using a 1-stage technique. The implants were placed in healed sites (43.9%), fresh extraction sockets (37.4%), or recent extraction sites (2 months postextraction) (18.7%). Before restoration, healing times of 3 to 4 months in the mandible and 5 to 6 months in the maxilla were allowed. The entered implant length in the osteotomy site before contacting the bony walls (EILOS) was compared, as well as the number of turns and the time required to seat the implants. Cumulative survival rates (CSRs) were calculated for up to 18 months of follow-up after surgery. Results: The EILOS was between 47.3% and 57.6% of implant length for the NT implants; for the standard implants, it was between 12.0% and 21.2%. With the NT implants, the number of turns and the placement time were reduced by 61% to 64% and 61% to 65%, respectively. In the clinical study, 4 implants failed during the healing period; none failed after prosthesis placement. The CSR was 97.79% for implants placed into fresh or recent extraction sites; in healed sites, the CSR was 98.75%. The cumulative prosthetic success rate was 100%. Discussion: This new implant design is seated with special drills; the drilling sequence requires less time and less torque than that used for standard implants. The low failure rate after prosthetic loading was consistent with that observed for standard Osseotite implants. Conclusion: These preliminary data suggest that the NT implant can be predictable in healed sites and fresh or relatively recent extraction sockets.

This multicenter prospective clinical evaluation was undertaken to determine the therapeutic success and marginal bone level stability of 3is self-tapping and ICE implants after 3 years of prosthetic loading. Between July 1995 and June 1996, 189 completely or partially edentulous patients were treated with 614 machined-surface screw-type commercially pure titanium implants (self-tapping or ICE). Two hundred seventy-seven self-tapping implants were placed in 85 patients (average age of 56 years), and 337 ICE implants were placed in 104 patients (average age of 61 years). A total of 360 implants (58.6%) were placed in posterior segments. Easier placement was reported with the ICE implant in normal or dense bone. For the self-tapping implants, survival rates of 92.9% and 91.6% were noted after 1 and 3 years of prosthetic loading, respectively. Survival rates of 95.4% and 93.8% were obtained with the ICE implant for the same periods. Late failures (after loading) were more common than early failures (before loading) for both types of implants. The marginal bone level of 238 self-tapping implants (85.9%) and of 307 ICE implants (91%) was radiographically evaluated at 3 years. Marginal bone level was at the first thread for 95.1% of implants. A loss of marginal bone level of 2 to 4 threads was noted for 4.9% of the evaluated implants. No implant showed bone loss greater than the fourth thread. Overall survival rates of 94.3% and 92.9% were obtained after 1 and 3 years of prosthetic loading, respectively, for 596 and 588 implants. Keywords: bone density, clinical trials, dental implants, multicenter study, self-tapping dental implants