Clinical outcomes of dental implants placed with varying insertion torques: a 3-year prospective analysis

This prospective study evaluated the short- and long-term outcomes of dental implants over a 36-month follow-up according to the achieved insertion torque values.

Patients requiring a single implant were recruited and classified by insertion torque (IT): low (10-29 Ncm), regular (30-50 Ncm), high (51-100 Ncm), and very high (> 100 Ncm). Outcomes assessed over 36 months included implant survival, success, marginal bone loss (MBL), and postoperative pain (POP), measured with a 10-cm VAS immediately after surgery, and at 24 hours, day 2, day 4, week 1, week 2, and week 3. Survival was analyzed using Kaplan-Meier estimates and Cox regression, and multivariate models were applied to identify predictors of MBL and POP.

A total of 230 patients were included. At week 3, the POP in the very high-IT group (3.08 ± 2.77) was significantly higher than other groups (0.08 ± 0.55, P .001). A total of 15 implants failed in the first 2 months. The overall survival rate after 36 months was 78.1% for the very high-IT group and 97.9% for the regular-IT group. The survival rate was also reduced in patients who smoked compared with nonsmokers (78.1% and 98.3%, respectively). Significant failure predictors included: high IT (HR = 5.24), smoking (HR = 13.96), and maxillary placement (HR = 9.03). The multivariate analysis revealed significantly increased MBL associated with four key factors: high IT (> 100 Ncm), type I bone density, smoking status, and anterior maxillary placement (P .001).

IT exceeding 100 Ncm was associated with increased POP, greater MBL, and reduced implant survival rates. The combination of high IT creating excessive interfacial stresses in dense (type I) bone, compounded by smoking-impaired healing and the thin cortical bone of the anterior maxilla, resulted in significantly greater MBL.