The Effect of Insertion Torque on the Clinical Outcome of Single Implants: A Randomized Clinical Trial

Background: The insertion torque value has been extensively used as an indicator for implant primary stability, which is considered a determining parameter for the implants success. Purpose: The primary goal of the present randomized clinical trial was to evaluate and compare the clinical outcome for implants placed with high insertion torque (between 50Ncm and 100Ncm) and regular insertion torque (within 50Ncm) in healed ridges. Materials and Methods: Partially edentulous patients, missing one or more mandibular or maxillary teeth, having an adequate amount of bone, requiring implant placement, were randomized to receive Blossom CT implants with regular insertion torque (<50Ncm) or CT implants with high insertion torque (≥50Ncm). Implants were left to heal submerged for 3 months. Implants were restored with individualized abutments and cemented metal-ceramic crowns. Acquired measurements were: insertion torque values (IT), thickness of buccal bone plate after implant osteotomy preparation (BBT), marginal bone level (MBL), and facial soft tissue level (FST). All patients were followed 12 months after implant placement. Results: One hundred sixteen implants were placed in one hundred sixteen patients and enrolled for the study. Fifty-eight implants were randomly allocated in regular-IT and high-IT groups with a mean insertion torque ranging from 20Ncm to 50Ncm and from 50Ncm to 100Ncm, respectively. Three implants failed, and another five implants showed at the 12-month evaluation a marginal bone loss (ΔMBL) greater than 1.5mm, being considered unsuccessful. Conclusions: The findings suggested that implants inserted with high-IT (≥50Ncm) in healed bone ridges showed more peri-implant bone remodeling and buccal soft tissue recession than implants inserted with a regular-IT (<50Ncm). Moreover, sites with a thick buccal bone wall (≥1mm) - after implant osteotomy site preparation - seemed to be less prone to buccal soft tissue recession after 12 months than sites with a thin buccal bone wall (<1mm).