An assessment on cross-sectional view of the mandible by linear tomogram of panorama

Hong, Soon Ki; Kim, Jae Duk

Abstract

PURPOSE: To evaluate the precision of measurements of distances and angle in the cross-sectional views of linear tomogram of panorama and to assess the technique for visualizing the mandibular canal.
METHODS
Ten dry mandibles were radiographically examined with 3 continuous cross-sectional views of linear tomogram of panorama and 4 continuous computed tomograms. The distance between the superior border of canal and alveolar crest and the bucco-lingual width of alveolar bone at the level of the superior border of canal and the angle between the two lines above were measured. Measurements were performed by radiologist and implantologist group and compared with measurements on computed radiograms of the same areas.
RESULTS
The measurements differences for the distance of alveolar bone height between in panorama and in CT showed 0.9mm+/-0.6mm by radiologists and 1.3mm+/-0.8mm by implantologists. There was no statistically significant difference between two groups' measurements. The differences in measurements for the distance of alveolar bone width between in panorama and in CT showed 0.5mm+/-0.8mm by radiologists and 2.5mm+/-1.4 mm by implantologists. There was significant difference (p<0.05) between two groups' measurements. The average bucco-lingual inclination of alveolar bone above mandibular canal was average 95.8degrees in CT. The difference of measurements between two groups was average 1+/-0.9degrees. Three cross-sectional views of panorama could show that the mandibular canal crosses antero-lingually and slopes inferiorly from the posterior segment of the mandible.
Conclusions
: The measurements in the linear tomogram of panorama by radiologists gave the accurate values of the distances and the angle compared with the values in computed tomograms.