Incidental cone-beam computed tomography diagnosis of pre-eruptive intracoronal resorption in an impacted maxillary third molar: a case report

Pre-eruptive intracoronal resorption (PEIR) is an odontoclast-mediated process that develops in the coronal dentine of an unerupted tooth, beneath radiographically intact enamel. Because it causes no symptoms, it is usually detected incidentally on radiographic examination. Although classically reported in children and adolescents, recent cone-beam computed tomography (CBCT) studies of impacted and unerupted teeth show that its prevalence rises with age, so the lesion may also be encountered in older adults. A 57-year-old woman was referred for CBCT as part of comprehensive dental rehabilitation, with no clinical suspicion of resorptive disease. An unusual shaped impacted maxillary right third molar was first noted on her existing panoramic radiograph but could not be characterised further because of anatomical overlap and projection distortion. Two oral and maxillofacial radiologists then independently reviewed the entire CBCT volume plane by plane, beyond the endodontic and implant questions that had prompted the scan, and identified a mixed-density defect within the coronal dentine beneath a radiographically intact enamel cap, with no communication with the pulp. Multiplanar reconstruction localised the defect and mapped its three-dimensional extent, supporting a radiographic diagnosis of PEIR. Because the tooth had been asymptomatic for decades and extraction of a deeply impacted molar would carry appreciable surgical morbidity, it was managed conservatively; follow-up was based on symptom reporting and low-dose two-dimensional imaging rather than repeat CBCT. Histopathological confirmation was therefore not obtained. CBCT clarified a PEIR lesion that panoramic imaging had left ambiguous. Because reviewing the whole imaging volume is a professional obligation in every examination, the case illustrates how a clinically silent incidental finding can be identified and then managed through a patient-centred assessment of benefits and harms.