Assessment of proximity of impacted mandibular third molar roots to the mandibular canal using intra oral periapical radiography and cone-beam computerized tomography: A comparative study

Objective: To assess the reliability of fi ve intra oral periapical radiography (IOPAR) radiographic signs, and to compare the reliability of IOPAR with that of cone-beam computerized tomography (CBCT) for determining the proximity of impacted mandibular third molar and mandibular canal. Methods: The present study consisted of 50 subjects, in age group of 18-30 years with impacted mandibular third molar visiting the department, Oxford Dental College and Hospital, Bengaluru. Relationship of impacted mandibular third molar with the mandibular canal was assessed using IOPAR signs and CBCT fi ndings. The 5 radiographic signs i.e. darkening of roots, diversion of canal, narrowing of canal, presence of cortication, and interruption of white line seen on IOPAR, were correlated for the proximity and involvement with CBCT fi ndings for the same. Results: In this study only 4% (2) subjects showed absence of corticalization on CBCT compared to diff erent radiographic (IOPAR) signs in all subjects. Among these two subjects diagnosed with an absence of corticalization, 50% (1) presented with a radiographic sign of darkening of roots and both i.e. 100% (2) presented interruption of white lines on IOPAR the mean and SD values of distance from mandibular third molar root to mandibular canal were 2.25 and 1.48 respectively in CBCT. Conclusion: This study showed the poor reliability of radiographic signs of IOPAR predicting the proximity of mandibular third molar root with mandibular canal related to CBCT fi nding. This creates the controversy and questions regarding the radiographic signs of IOPAR reliability with CBCT fi ndings that was found far more precise and accurate as per for future prospects.