Longitudinal analysis on the effect of insertion torque on delayed single implants: A 3-year randomized clinical study.

Background: Implant stability is commonly related to insertion torque. Recently, it has been suggested that higher insertion torque may lead to greater bone resorption.

Purpose: The aim of the present randomized clinical study was to evaluate the role of different insertion torque values in terms of implant success, marginal bone loss, and facial soft tissues recession.

Materials And Methods: Patients requiring a single dental implant were recruited and randomized to receive one of two implants with the same macro-geometry but different cutting designs. First group consists of a 90 degrees cutting groove know as self-tapping implant, and the second group known as Blossom™ cutting groove. (Intra-Lock, Boca Raton, Florida). The insertion torque (IT) was assessed and two groups followed: high-IT (≥50 Ncm) group and regular-IT (<50 Ncm) group. After 3 months, all the implants were restored. At baseline, buccal bone thickness (BBT) was recorded. During the 3-year survey, the following outcomes had been registered: implant failures and success, radiographic marginal bone level around dental implant (MBL) and facial soft tissue level (FSTL).

Results: A hundred and sixteen implants were placed in healed sites. The overall survival rate after 3 years was 96.5%. The Cumulative Success Rate was 91.3% for the High IT group and 98.2% for the Regular IT group. The mean marginal bone loss and facial soft tissue recession, at a 3-year evaluation, were significantly greater for the High-IT group and in the mandible than that reached in the Regular-IT group and in the maxilla.

Conclusion: Present findings showed that implants placed with higher insertion torque in mandible led to greater bone resorption and mucosal recession than that registered for implants placed with a regular IT. Moreover, sites with a thick buccal bone wall (≥1 mm) showed smaller recession at the facial soft tissue level after 3 years.