Dentigerous cyst encloses the crown of the unerupted tooth and is the most common odontogenic cyst . Clinical manifestations of this cyst include swelling, teeth displacement and delayed eruption of a permanent tooth and usually occur in the second and third decades . Radiographically, the cyst appear as a well-defined unilocular radiolucency surrounding a crown of unerupted tooth . Different treatment options exist for these lesions. Removal of the cyst together with the affected tooth can be too aggressive and more conservative ones such as marsupialization could be selected to allow for the eruption of the teeth related to the cyst .
A 10-years-old boy was referred to the department of pediatric dentistry at Shahid Beheshti University of medical sciences with chief complaint of pain and slight swelling in the left side of mandibule for two weeks. Medical history was negative. Extraoral examination revealed slight facial asymmetry. Intraoral examination revealed a hard submucosal mass and bony expansion of the buccal cortical plate of the alveolar ridge on the left side of the mandible [ Fig. 1 ]. Radiographic examination including panoramic radiography and cone beam computed tomography (CBCT) showed a unilocular well-defined radiolucency associated with an unerupted mandibular left second premolar that displaced the unerupted second premolar to the lower border of mandible beginning from left first premolar to mesial root of permanent first molar [ Fig. 2 ].
A provisional diagnosis of dentigerous cyst was made on the basis of the clinical and radiographic findings. Considering the size of the cyst, marsupialization of the cystic cavity with preservation of permanent tooth was planned [ Fig. 3 ]. After signing informed consent, the patient was treated by extraction of the left mandibular first and second primary molars and marsupialization of the cystic cavity under local anesthesia.
During the surgical procedures a biopsy was made and the histopathological examination confirmed the clinical diagnosis of the inflammatory dentigerous cyst. Histopathologic examination showed cystic lesion lined by nonkeratinized stratified squamous epithelium. In connective tissue cyst wall scattered mixed inflammatory cells infiltration, russell bodies, hemorrhage,extravasated RBCs were seen [ Fig. 4 ].
An obturator was designed to maintain wound patency after marsupialization and was used for six weeks [ Fig. 5 ]. The obturator had a component that extended down into the cystic cavity through the top of alveolar crest and the component was shortened every two weeks as the cystic cavity volume was decreased.