Experimental procedure in which an implant is subjected to unscrewing to determine the relative strength of attachment between the implant and bone. It is usually done on a comparative basis between differing implant surface topographies or roughness. It is assumed that the reverse torque value (RTV) will increase as the process of osseointegration progresses. RTT of implants to a torque of 20 Ncm has also been described as a method for determining the success of machined surfaced, threaded implants in clinical situations.