- 期刊
Effect of Anti-rotational Design and Counter-torque Device on Peri-implant Bone Stress During and After Preload-A Preliminary Results
摘要
Purpose: Tightening an abutment screw (preload) may cause implant deformation and induce peri-implant bone strain. Preload may also transmit the torque to the peri-implant bone. This study's aims were to evaluate whether an anti-rotational design at abutment-implant interface and the application of a counter-torque device during preload would affect the transmission of torque and the development of peri-implant bone strain. Materials and Methods: A MirusCone abutment (MC) with an anti-rotational abutment-implant design and its con guration counterpart, without an anti-rotational design, Multiunit abutment (MU) were used for testing. The abutment screw of each type was tightened, with or without the counter-torque device application (wct and woct, respectively), by an electronic torque controller with 20 N-cm torque. During preload, the torque transmitted to implant-bone interface was measured by a torque gauge grasping the implant replicas (Nobel Biocare) for each group (MCwct, MCwoct, MUwct, MUwoct). The strain on the implant replica resulted from the clamping force of preload was measured from a snacked delta rosette strain gauge bonded on an implant replica embedded in an epoxy resin block. The outputs from the strain gauge were analyzed with Spike 2 software. The magnitude (μ) and direction of maximum principle strain (MPS) were calculated according to the formula provided by the manufacturer. Results: Application of a counter-torque device diminished about 90% of the torque transmitted to the torque gauge in both MC and MU abutments. There was no significant difference in the torque transmitted between MC and MU abutments. There is no significant difference in MPS magnitude among the groups after the preload, I.E. MCwoct: -242.48 μє, MCwct: -231.71 μє, MUwoct: -215.95 μє, MUwct: -221.00 μє. The direction of MPS was parallel to the long axis of the implant replica in all groups.