Frequency of non carious triangular shaped radiolucensies on bitewing radiographs

Introduction: The assessment of bitewing radiographs requires knowledge of radiographic anatomy and pathology and the various phenomena which produce deceptive radiolucent area that closely mimic carious lesion and may lead to false positive diagnosis. In this study we assessed the frequency of the "Non-carious triangular shaped radiolucency" phenomenon which appears in the mesial surfaces of upper primary and first permanent molars on bitewing radiographs due to the anatomical characteristics of the rhomb-shaped from an occlusal point of view, in particular the crown's receding mesial surface from the mesiobuccal towards the distopalatal side that produces a prominent palatal cusp whose mesial edge superposes the crown in the radiographic image, and the mesiodistal width is significantly smaller at the cervical neck than it is at the crown. These two characteristics produce a triangular shaped radiolucency that mimics carious lesion. Methods: A retrospective study that includes 210 bitewings radiographs of 105 children, average age 6.4 years. Results: The Non-carious triangular shaped radiolucency is a phenomenon that can be observed on the mesial surfaces, non of the distal surfaces displayed it. It was most frequently present on upper second primary molars (32.7%), 23.4% of the upper first primary molars and 4.1% of the upper first permanent molars. Conclusions: In the mesial surface of upper primary and permanent molars where the frequency of the Non-carious triangular shaped radiolucency was fairly high. Due to its high occurrence in the bitewing radiographs which constitute an important method of caries detection, dentists should be aware of this phenomenon, to prevent unnecessary treatment after false positive diagnosis.