Objective Throughout investigating imaging features of supernumerary teeth in the third molar region (ST-TMR), aims to conclude their radiographical characteristics. Methods In this study, 46 patients’ (55 teeth) X-ray materials (panoramic imagings or cone beam CT ) were collected and analysed, and investigated their location, morphology, size, whether or not concomitant lesions, etc.. Results The unilateral maxillary with single tooth is common (36/46), and those of the mandible, the bilateral and two teeth in the same area are rare. Twenty-one ST-TMRs’ cone beam CT show that impacted teeth are more (18/21); dismolars are more (9/21), others distribute in the lingual or buccal side, root or crown of third molar or shift to its mesial; 5 cases are close to the maxillary sinus floor, 1 case goes into pterygomaxillary joint; meanwhile its volume is smaller than that of the related third molar with different shape-forms, and the conical shape is common (13/21), others including nodular, similar premolar and similar molar; concomitant lesions include dentigerous cyst, anterior supernumerary teeth, adjacent teeth impacted, the change of periodontal bone, root resorption of adjacent teeth, adjacent teeth caries, other multiple impacted teeth, etc.. Conclusion The female is more than male in the incidence of ST-TMR, and the unilateral maxillary with single tooth is more common; cone beam CT can accurately evaluate the location, morphology, size, concomitant lesions of ST-TMR, etc., to provide the basis for clinical diagnosis and treatment.
