Introduction: Odontogenic keratocyst tumour (OKT) is a benign pathology. Affects more mandibule than maxilla. Usually asymptomatic, their finding is commonly radiographic. Two cases are described.

Case 1: Male with radiographic finding of extensive radiolucent lesion in the left upper premolars area. The Cone Beam confirms extensive osteolytic extending from right central incisor to distal of second premolar, occuping the sinus cavity and compromising the buccal bone plate. Incisional biopsy was performed, installs a decompression cannula indicated chlorhexidine rinse after every meal. Antibiotic therapy was prescribed.

Histopathology: OKT. Radiographic control showed reduction of the lesion. Enucleation and bone graft was performed.

Case 2: Extensive radiolucent lesion in left posterior mandibular body and ramus. ConeBeam evidenced mandibular body and ramus lesion that deform sigmoid notch.

Histopathology: Mandibular keratocyst. Decompression cannula and chlorhexidine. Radiographic control demonstrate the lesion regression. After two years a total lesion excision and residual particulated bone filler was performed.

Conclusions: The OKT is a lesion that presents significant important challenges in its management regarding conservative treatment, resection and monitoring. For treatment planning and monitoring of the lesion, the ConeBeam to measure real distances and three-dimensional reconstructions is the key to study the injury.