A Comparison Study Of Digital Panoramic Radiography And Spiral CT For Interradicular Space Measurement

Objective:The purpose of this study is to evaluate the horizontal distortion and the vertical distortion of the digital panoramic radiography,and to compare the measurements between the digital panoramic radiography(DPR) and spiral CT(SCT) of the interradicular space of to provide preoperative guidance for placement of Miniscrews. Materials and Methods:In study one , 2 human skulls were examined with DPR,each marked with 16 metallic spheres . Horizontal and the vertical dimension of the metallic spheres were measured,then calculate the horizontal distortion and the vertical distortion in different areas of DPR . In study two, 6 volunteers with individual normal occlusion were examed with DPR and SCT. For each interradicular space of the premolar and molar regions, mesiodistal distances were measured at 2.5mm,5mm,7.5mm and 10 mm from the alveolar crest with DPR and SCT. Results:The vertical distortion in different areas of DPR demonstrated no statistically siginificant difference and the horizontal distortion do . The average of the vertical distortions is 21.61%±1.16, The average of the horizontal distortions is -4.9% of the interradicular spaces between the maxilla canine and first premolar,the maxilla first premolar and second premolar.It is 2.6% of the interradicular spaces between the maxilla second premolar and first molar. It is 6.1% of the interradicular spaces between the mandibular canine and first premolar,the first premolar and second premolar,second premolar and first molar. It is 10.3% of the interradicular spaces between the first molar and second molar of both maxilla and mandibular.In study two, the measurements of the interradicular spaces between the second premolar and first molar,the first molar and second molar of both maxilla and mandibular, which obtained by DPR and SCT showed non-significant statistically difference by Wilcoxon-test. Conclusion:The emendation of digital panoramic radiographs for interradicular space of molar region is helpful for implantation of miniscrew anchorage, but in premolar regions, SCT is available.