Nontraumatic Implant Explantation: A Biomechanical and Biological Analysis in Sheep Tibia.

Preclinical research in a sheep tibia model has been conducted to evaluate the underlying mechanisms of the nontraumatic implant explantation of failed implants, which allow placing a new one in the bone bed. Twelve dental implants were placed in sheep diaphysis tibia and once osseointegrated they were explanted using a nontraumatic implant explantation approach. Implant osseointegration and explantation were monitored by means of frequency resonance, removal torque, and angle of rotation measurement. The host bone bed and the explanted implant surface were analyzed by conventional microscopy and scanning electron microscope. Results show that osseointegration was broken with an angular displacement of less than 20°. In this situation the implant returns to implant stability quotient values in the same range of their primary stability. Moreover, the explantation technique causes minimal damage to the surrounding bone structure and cellularity. This nontraumatic approach allows the straightforward replacement of failed implants and emerges as a promising strategy to resolve clinically challenging situations.