The role of quantitative single photon emission computerized tomography (SPECT) in the osseous integration process of dental implants

Objective. To evaluate the integration process of endosseous dental implant s by using quantitative bone single photon emission computerized tomography (SPECT). Methods. Five consecutive patients receiving titanium implants (Astra Tech, Molndal, Sweden) in the normal edentulous jaw were evaluated by bone SPECT before loading and at regular intervals up to 5 months after loading. Oste oblastic activity at the implant site was compared with activity within the skull (reference) to calculate an osteoblastic activity index (Al). Results. A time activity curve obtained by plotting Al against time over 5 months showed 3 distinct phases of osteoblastic activity: (1) a rise in ost eoblastic activity, part of which may reflect postoperative changes, (2) ma ximum activity about 1 month after implant, and (3) a gradual falloff in th e Al, which returned to pre-implant levels at about 4 months. Conclusions. We conclude that this method offers a simple, reproducible, ob jective, and physiologic approach to studying the osseous integration proce ss that occurs after endosseous dental implants. In this small series of pa tients, this osseous integrative process appears to have become established approximately 4 months after loading. This method also has the capability of quantitating bone activity in absolute terms of mu Ci/gram (microcuries per gram) and can be useful when bone grafting and other surgical procedure s are involved.