Objectives: To examine oral and maxillofacial lesions other than those related to the chief complaint in panoramic radiographs taken at the department of paediatric dentistry at our hospital.

Methods: We retrospectively reviewed all 1092 patients who had visited the department of paediatric dentistry at our hospital and had a panoramic radiograph taken between August 1999 and October 2004. The following information was obtained from the patients' files and panoramic radiographs: gender, age, chief complaints and the presence or absence of lesions.

Results: Lesions were observed in 140 of the 1092 panoramic radiographs (12.8%). Among the 140 patients discovered to have lesions in the panoramic radiographs, 66 (47.1%, or 6.05% of the entire group of 1092 patients) had different lesions from those underlying the chief complaint. These 66 patients ages ranged from 3 years to 14 years and the lesions involved 39 (59.1%) missing teeth, 20 (30.3%) mesiodentes, 4 supernumerary teeth, 1 odontoma, 1 radicular cyst and 1 impacted tooth. The missing teeth were observed in the central and lateral incisor, canine, and first and second premolar positions of both jaws, especially in the lower lateral incisor and upper central incisor positions.

Conclusions: We were able to detect incidental lesions at a rate of 6.05% (66 of 1092 patients) and at a relatively early age (mean 6.8 years) in the present study. Early treatment of these lesions could avoid maxillofacial deformity and other complications.