RESUMEN
Dentigerous cysts are benign odontogenic cysts that are associated with the crowns of permanent teeth. They are developmental epithelial-lined lesions which are formed from fluid accumulation in the space between the reduced enamel epithelium and the surface of crown. This may occure due to the obstructin of venous return caused by tooth impaction. The most prevalent location of dentigerous cysts are the third molar of mandible. While the single dentigerous cysts are the second most common odontogenic cysts following the radicular cysts of jaw, multiple cysts are observed in patients with some conditions such as mucopolysaccharidosis type IV, basal cell nevus syndrome, and cleidocranial dysplasia. They occur in young patients in the second or third decades of life, but it is a rare occurrence for children. A sixteen-year-old girl with painful swelling in the right mandible visited to our department. All routine laboratory test results were within normal limits. However, we were able to diagnose that she had facial asymmetry. Computed tomography showed a well-defined soft tissue mass obliterating right mandible ramus with an impacted tooth. We performed total enucleation of cyst and molar tooth. The pathology revealed a non-keratinized squamous epithelial lined cyst associated with an undamaged tooth.