Intraoral vs. Extraoral Bitewing Radiography: Alveolar Bone Level Measurement Accuracy

Objectives: The objective of this study is to compare the dimensional accuracy of extraoral and intraoral bitewing radiographs acquired via the Sirona ortho xg-plus and the Gendex intraoral machines respectively to evaluate alveolar bone levels.
Methods: A pilot study was carried out to evaluate the dimensional accuracy of the two radiological examinations. Two pieces of gutta percha measuring approximately 7.0 mm and 14.5 mm were placed in a dry skull at the level of the alveolar crest, on the buccal aspect of the ridge, in the region of the left maxillary premolars and molars in vertical and horizontal inclinations, respectively.
For the intraoral bitewing radiography, the dry skull was exposed once via Gendex at 65 kVp, 7 mA, and 0.10 seconds for one left side bitewing. For the extraoral bitewing radiography, the dry skull was exposed once via Sirona at 64 kVp, 8 mA, and 8.7 seconds generating four bitewings that capture both the gutta percha on one of those bitewings. The length of guta percha in both intraoral and extraoral bitewing radiographs were measured using the measuring tool in the Emago software and compared to that of the real measurements.
Results: The horizontally placed gutta percha in the intraoral bitewing radiograph measured approximately 21.3 mm while the vertically placed gutta perch measured 10.7 mm. The respective measurements using the extraoral bitewing technique was approximately 15.8 mm for the horizontal and 8.0 mm for the vertical. The dimensional accuracy of the extraoral bitewing was more accurate at 91.8% and 87.5%, whereas the accuracies of the intraoral bitewing were 68.1% and 65.4%.
Conclusions: Within the limitations of this pilot study, it can be concluded that the dimensional accuracy of extraoral bitewing radiography is more accurate than that of the intraoral bitewing radiography. Additional trials will be performed to validate this finding.