Effects of positioning upon the vertical dimension on cone beam computed tomography

Abstract

Aims: The present study was performed to investigate the effects of different positioning modalities on vertical dimensional measurements of potential implant sites in cone beam computed tomography (CBCT) images. Methods: Twenty-eight implant shaped stainless steel pins were placed in every tooth location in a dry skull and CBCT images of these pins were obtained with the skull in different positions in lateral and forward-backward planes. The following angles were used in both planes: –10°, –5°, 0°, +5° and +10°. The CBCT images were obtained with the Kodak 9000 CBCT imaging system (Carestream Health Inc, Rochester NY, USA). Panoramic slice views were used for measurement allowing all pins to be viewed on the same slice. The measurements of vertical dimensions of the pins were performed twice on the obtained images by the same observer according to tooth regions and the data was statistically analyzed. Results: Statistical analysis revealed that for forward-backward movements measurement differences were statistically significant in maxillary anterior, mandibular anterior and mandibular premolar regions and for lateral position changes statistically significant differences were observed in the maxillary premolar and maxillary molar regions for imaging modalities changing between the angles of –10° and +10°. Conclusion: Changing the skull position reduces the accuracy of vertical dimensions on CBCT scans. The results of the present study showed that skull movements between –10o and +10o effects the anterior regions significantly, but for other regions of the jaws the measurements are within a clinically acceptable range.