Success of Dental Implants Placed Without Primary Stability: A Retrospective Study in a Private Practice :

This retrospective study evaluated the success rates of dental implants placed without primary stability in a private practice setting, utilizing three contemporary implant systems (Neodent GM Helix, Biotem AR, MegaGen AnyOne) and stability-oriented protocols.

Records from 63 patients receiving 97 implants (Neodent GM Helix, n=35; Biotem AR, n=39; MegaGen AnyOne, n=23; 76 in maxilla, 21 in mandible) placed between January 2021 and September 2024 in Qazvin, Iran, were reviewed. Absence of primary stability was defined as insertion torque 10 N·cm and/or intraoperative spinning. Immediate placements (n=23) received grafting; all implants were submerged, uncovered at approximately 3 months, and loaded at approximately 4 months. Success was assessed using modified Albrektsson/Buser criteria. Statistical analysis included Wilson 95% confidence intervals and Fisher's exact or χ² tests.

Overall success rate was 95.9% (93/97; 95% CI 89.9-98.4%). Success rate by system was 97.1 % (34/35) for Neodent, 94.9% (37/39) for Biotem, 95.7% (22/23) for MegaGen with no significant difference among the systems (P=0.91). Immediate placements achieved a 100% success rate (23 out of 23 implants), compared to 94.6% for delayed placements (70 out of 74 implants), with no significant difference (P=0.58). Success rates were 96.1% in the maxilla (73 out of 76 implants) and 95.2% in the mandible (20 out of 21 implants), with no significant difference (P=1.00). Four early failures occurred (≤4 weeks), all in delayed placements; no late failures were observed. Systemic conditions (diabetes, hypertension, hypothyroidism) did not increase failure rates (P=0.61). All implant failures occurred in posterior regions and delayed timing of placement, while anterior and immediately placed implants achieved 100% success.

In carefully selected cases employing atraumatic techniques, socket grafting and sealing for immediate sites, and conservative loading protocols, implants placed without primary stability demonstrated clinically acceptable success rates comparable to private practice benchmarks. Nonetheless, the absence of mechanical primary stability remains a risk factor, particularly in the posterior maxilla or type IV bone; these findings do not advocate replacing primary stability. Prospective, multicenter studies with standardized Implant Stability Quotient (ISQ) monitoring are recommended.