Tightening of healing abutments: influence of torque on bacterial proliferation risk, an in vitro investigation

Abstract

AbstractGap at the implant-healing abutment junction can increase the risk of bacterial proliferation. In this study, we determined the leakage at the microgap, and we evaluated hand screwing among clinicians.The torques tested with nitrogen gas flow were 10, 15, 20, and 30 N cm, and 54 clinicians were asked to torque down a healing abutment as for a surgical procedure.There were no significant differences between 10 and 15 N cm, with a total lack of tightness. For 20 and 30 N cm, there was a notable decrease in leakage. The torque achieved by hand was <10 N cm for 61.7% of the clinicians, between 10 and 15 N cm for 29.1%, between 15 and 20 N cm for 8.0%, and between 20 and 25 N cm for 1.2%.There was a significant difference related to the strength of tightening. Under the conditions of our experiment, the gap of connection was reduced with a torque of ≥20 N cm. Only a small portion of the clinicians could obtain these values by hand. Therefore, a dynamometrical manual wrench should be used to minimize the gap during the osseointegration period.