Method: In a retrospective assessment we reviewed all patients who had presented for insertion of a palatal implant between January 2003 and December 2007 at the University Hospital Mainz. In all patients orthodontic treatment required a stationary anchorage. On the basis of lateral radiographs, the bone base was evaluated as follows: a) sufficient (bone height > 4mm in the implant axis), b) ambiguous or c) insufficient (bone height < 4mm in the implant axis). In group a) the surgical insertion procedure was performed without further radiological investigation whereas group c) required other types of anchorage. In cases of an ambiguous bone situation (group b), further diagnostic procedures (CT/DVT) were performed.
Results: During the observation period, 105 patients aged 12 to 63 years were investigated. Fourteen patients decided not to undergo the treatment for financial reasons. In 89 patients (97.8%) the lateral radiographs showed sufficient bone in the vertical aspect. In all of these cases, the presence of adequate bone was confirmed intraoperatively. As a result, primary stability of the implants could be achieved. Further investigations were performed in 2 patients (2.2%) of group B (one CT, 1 DVT). Eventually one patient had insufficient bone whereas the second had sufficient bone.
Conclusions: Lateral radiographs permit correct and reliable evaluation of the quantity of vertical bone in preoperative diagnosis of palatal implants. Only the presence of a borderline quantity of bone is an indication for CT or DVT.