Male patient, 17 years old, referred to the Maxillofacial Surgery Service of the University of Talca, for presenting a lesion at the level of the right mandibular angle, revealed in a cervical lateral teleradiography control, following a car accident.
The patient reported no personal or family history. History of smoking, alcohol and drugs were negative, as were any medication intake or drug allergies. The general physical examination was not compromised. No aesthetic or functional alterations were observed on extraoral clinical examination. Intraoral palpation revealed a slight increase in volume in the posterior area of the mandibular vestibule.
In the conventional radiological study an extensive unilocular image of mixed density was observed, with radiopaque predominance, surrounded by a radiolucent band with net corticalised limits located in the area of tooth 48, partially overprojected in the roots of tooth 47 with bulging of the bony slabs and with rejection of tooth 48 towards the distal and cephalic region. The mandibular canal was displaced towards the basilar edge in the segment corresponding to the mandibular body and rejected distally in the ascending branch.
The study was complemented with a computed axial tomography scan showing a hyperdense lesion, with clear and corticalised limits, with widening of the bony tables. Its dimensions were: antero-posterior 25.9 mm, vestibulo-palatine 21 mm and 28.3 mm in greatest cephalo-caudal diameter.
The acquisition of the images was processed with Dentascan® software, obtaining axial, panorex and transversal reconstructions of the area of interest, which confirmed the proximity to the mandibular canal, as well as the involvement of both tables.
The differential diagnosis for this case was immature complex odontoma, ameloblastic fibroodontoma, calcifying epithelial odontogenic tumour and calcifying epithelial odontogenic cyst.
After the radiological study, an incisional biopsy was performed under local anaesthesia, which included both soft and hard tissues, showing calcified dentine-type tissue, with areas of minor calcification and lax fibrous connective tissue that resembled the stellate reticulum of the dental organ. The periphery showed fibrous connective tissue and some small areas showing epithelium of odontogenic origin with the presence of peripheral cylindrical cells of the ameloblast type. The sample was irregular and showed no denticle structure. Accordingly, the histological diagnosis was a lesion compatible with an odontoma in formation with the presence of ameloblastic changes.
Enucleation of the lesion was performed under general anaesthesia, using an extraoral approach at the level of the right mandibular angle to facilitate modelling and subsequent placement of a rigid osteosynthesis. In this way the affected area was accessed, finding a very diminished vestibular table, which was removed to make way for the exposure and complete elimination of the lesion, concluding with a curettage of the surgical bed. The remnant of healthy bone tissue was very poor, so the placement of a 2.4 reconstruction plate at the level of the mandibular angle and body was planned to provide greater strength and prevent a pathological fracture. Immediate grafting was not planned due to the possibility of recurrence.
Histopathological examination of the operative specimen revealed a greater amount of ameloblastic tissue and a diagnosis of ameloblastic fibroodontoma was made.
Healing went smoothly. Although this lesion has a low recurrence rate, the patient is monitored regularly and there have been no signs of recurrence to date.
