In vitro evaluation of horizontal implant micromovement in bone specimen with contact endoscopy

Primary stability of dental implants is mandatory for their osseointegration. A method is described that allows objective measurements of implant displacement in bone sites during lateral loading. Ten samples of bovine bone (2 cm x 2 cm) with bone type II, III, and IV according to Lekholm and Zarb were used for the experiment. Ten Semados dental implants of 15-mm length and 3.75-mm diameter were placed. All implants were loaded with lateral forces of 5, 10, 20, and 30 N through 8-mm abutments for 2 seconds each. Lateral displacement was observed by means of contact endoscopy. Micromovement was detected with the help of a transmitter strip attached to the abutment. Endoscopic images were processed digitally and microdisplacement was calculated relative to the reference body (microscrew) placed adjacent to the implant. Micromovement observed varied with the force applied. Lateral force of 5 N resulted in a mean displacement of 39 microm; for 30 N, the mean displacement was 157 microm. Bone type also influenced the amount of movement. Contact endoscopy represents a new method for direct observation of implant movement relative to the bone surface in vitro. In combination with support immersion technique, contact endoscopy could be used as an office procedure to evaluate intraoperatively implant stability during functional loading.