Correction of Magnification Errors in Inferior Alveolar Canal Localization Using a Buccal Grid with Intraoral Periapical Radiographs: An In vitro Study

Objective: Accurate localization of the inferior alveolar canal (IAC) is crucial for determining implant length for mandibular dental rehabilitation. Intraoral periapical radiographs (IOPARs) offer a cost-effective alternative to Cone-beam computed tomographys that are the gold standard; however, they are prone to magnification and distortion errors which impact treatment planning. This study aimed to assess whether using a standardized grid with IOPARs improves measurement accuracy in locating the IAC. Methodology: An in vitro study was conducted using 15 dry human mandibles (30 samples). IOPARs of the first or second molars were taken bilaterally using a standardized 1 mm × 1 mm metal grid attached to the buccal surface, and based on the magnification of the grid, a derived length (DL) to the IAC was noted. The mandibles were then sectioned in the coronal plane to obtain direct anatomical measurements of the IAC position from the crest. The error in the radiographical length and the DL compared to anatomical length was measured and compared to check accuracy. Results: The mean radiographic error was 1.56 ± 0.27 mm (10.83%), whereas the mean derived error was significantly lower at 0.44 ± 0.14 mm (3.07%). There was a 71.81% reduction in measurement error and the difference was statistically significant ( P < 0.05). Conclusion: The modified use of a standardized grid with IOPARs significantly improves accuracy in localizing the IAC by reducing radiographic magnification errors as opposed to the conventional method of placing the grid on the film.