TRANSMISSION ELECTRON AND HIGH-VOLTAGE ELECTRON-MICROSCOPY OF OSTEOCYTE CELLULAR PROCESSES EXTENDING TO THE DENTAL IMPLANT SURFACE

Examination of the morphology of osteocytes within the bone supporting endosteal dental implants was performed using conventional transmissi on and high-voltage transmission electron microscopy (HVEM). The in vi vo dog model used 72 implants inserted into the premolar region of 18 experimental animals. Forty-eight implants in 12 dogs were used as ant erior abutments for fixed bridges for periods up to 12 months. The min eralized matrix of the supporting bone was either directly apposed to the implant surface or was separated from the implant by a narrow regi on of unmineralized matrix. Osteocytes were routinely observed to be c losely associated with the bone-implant interface, as well as at a dis tance from the implant. Osteocytes were found to extend cellular proce sses directly to the implant surface through canaliculi. The osteocyte processes contained microfilaments. The three-dimensional capabilitie s of HVEM elucidated the nature of these cell processes at the point o f exit from the osteocyte, as the processes extended through the miner alized matrix, and as the processes terminated at the implant interfac e. This report suggests that avenues of communication may exist betwee n the implant and the osseous cells, providing intriguing hypotheses r egarding biomechanical forces and osteogenesis at the implant interfac e. Furthermore, an electron-dense deposit was observed upon the inner confines of the canalicular wall, upon the outer aspects of the osteoc yte lacuna, and upon the outer aspect of the bone interfacing the impl ant. (C) 1994 John Wiley and Sons, Inc.