Torque-fitting and resonance frequency analyses of implants in conventional sockets versus controlled bone defects in vitro.

The primary stability of implants should be high on insertion into fresh extraction sockets. Torque-fitting and resonance frequency analyses (RFA) are used to assess primary implant anchorage and stability. The torque-fitting and RFA of implants placed in conventional surgical sockets and sockets with controlled coronal bone defects was compared. The possible relation between torque-fitting and RFA was explored. Ø 3.3 mm x 12 mm implants were placed in 16 sockets finalized with Ø 2.8mm surgical pilot drills in the right iliac crests of two fresh cadavers (control). In the test group, implants were placed into sockets prepared by Ø 2.8mm drill followed by Ø 4.2mm twist drills to a depth of 6mm to create circumferential controlled coronal bone defects (50% bone loss). Primary implant stability was assessed using insertion torque values (ITV) followed by RFA. Mean ITV and RFA measurements for test groups (7.83+/-0.91 N cm and 40.88+/-3.57) were significantly lower than controls (14.80+/-1 N cm and 66.31+/-0.9) (P<0.05). Reductions of ITV and RFA measurements in relation to bone defect were 47% and 38%. The existence of controlled bone defects eliminating contact coronally leads to decrease in torque-fitting and primary stability of implants. No relationship was observed between torque-fitting and RFA. Copyright 2009 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.