DOI: 10.1093/bjs/znad258.288 ISSN:

855 Mirror-Image Large Complex Odontomes

R Budhdeo, A Graham, M Harrison
  • Surgery



This report outlines a nine-year follow-up of two 10-year-old patients who attended the paediatric dental department reporting an absent mandibular first permanent molar (FPM). Both reported no pain, no familial history of hypodontia and no altered sensation in the inferior dental (ID) nerve distribution. Clinical examination revealed mandibular expansion in the unerupted tooth area.

Special Investigations

Panoramic jaw radiographs revealed extensive radio-opaque masses in the mandibular FPM area in both children, in mirror-image sites. Subsequent cone beam CT identified extensive displacement of the FPM with an associated large mixed radiopaque/radiolucent lesion in the body of mandible. Interestingly, the mandibular second permanent molar (SPM) was present in one case and absent in the other.


The provisional diagnosis for both cases was a complex odontome however, heavily calcified ameloblastic fibro-odontoma could not be excluded. Management involved surgical removal of the odontogenic tumour with FPM maintenance. Histopathology confirmed the diagnosis of a complex odontoma in both cases. On long-term review in both cases the FPM failed to erupt. Cystic follicular enlargement of the FPM in one case prevented eruption, and a coronectomy was performed in the other on the FPM apices were too close to the ID nerve to be extracted.


These cases highlight the importance of monitoring dental eruption patterns in childhood. Despite the mirror image diagnosis, multiple factors were considered when identifying treatment options for each individual patient. Aetiological questions regarding this particular odontogenic tumour type are raised by the presence or absence of the SPM.

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