463 - The diagnostic value of orthopantomograms in detecting resorption of lateral incisors associated with ectopic canines

C Hershaw N Mhani A Brown
Presented by: Catherine Hershaw
Royal Gwent Hospital

Introduction Orthopantomograms (OPGs) have traditionally been used as a diagnostic tool for root resorption in cases involving impacted canines. However, the introduction of cone-beam computed tomography (CBCT) represented a paradigm shift in dental & maxillofacial imaging. CBCT imaging is capable of providing accurate, submillimetre-resolution images that enable three-dimensional visualisation of the anatomy. Studies have shown OPG radiographs to have limitations when evaluating root fractures, periapical pathology & orthodontic root shortening. In our units, 40% of patients referred to secondary care present with ectopic canines. CBCT is undertaken in 54% of these cases. We evaluate the diagnostic value of OPG radiographs in diagnosing resorption, measured against CBCT as a gold standard, confirmatory tool. Method Forty consecutive patients with impacted canines between January 2018 & December 2019 were selected. A consultant orthodontist examined the OPG in isolation to detect the presence & extent of resorption of lateral incisors. The CBCT report was used to confirm the presence & extent of pathology. Results Nineteen maxillary right canines, eighteen maxillary left canines, one mandibular right canine & two mandibular left canines were assessed. Impactions were more prevalent in the maxilla (92.5%) with higher predilection towards females (65%). OPGs were found to have a sensitivity of 77.3% & a specificity of 11.1% & an accuracy value of 47.5%. Positive & negative predictive values were found to be 51.5% & 28.6% respectively. The extent of root resorption was correctly estimated from the OPG in only 16% of cases, with overestimation & underestimation occurring in equal proportion (42%). Conclusion This study demonstrates limitations of plain film radiographs & the merits of using CBCT in the accurate diagnosis of resorption of incisors. It also establishes the basis for future, larger scale studies where outcomes can be generalisable at a population level.
Consent Statement: There are no details on individual patients reported within the abstract.

Poster