Osseointegration of dental implants without primary stability: an experimental study in sheep

Abstract

Background and objective: Primary implant stability is considered necessary forachieving and maintaining osseointegration. This experimental study aimed to evaluate theoutcome of implants without primary stability, clinically and radiographically.Methods: Two adult sheep (3-4 years of age), 70 kg in weight, were included in the study.After sedation and local anesthesia, the lateral side of the basal bone of mandible isexposed by a single long incision. The implant bed performed in the inferior border of thebasal bone of mandible drilling to 5 mm in diameter and 10 mm in length. Five implantswere inserted into the basal bone of mandible for each side (right and left), but the sizes ofinserted implant was 3.8 mm in diameter and 10 mm in length, after 4 months the 2 sheepwere sacrificed and the universal torque ratchet was used to measure the stability of theimplant by a counter torque 30 N/cm test. Cone Beam Tomography (CBCT) was used toevaluate the implants radiographically.Results: Nineteen (from 20) implants successfully tolerated a 30 N/cm countertorque testcomprising (95%). Only one implant failed to osseointegrate (5%). During the healingperiod, no any adverse clinical signs reported.Conclusion: Dental implants may have a chance to osseointegrate even in the lack ofprimary stability.