To evaluate the effects of decompression in treating large maxillary cystic lesions.

25 cases of large maxillary cystic lesions were performed decompression during Oct. 2007-Oct. 2014. According to the clinical and radiological examination, morphology of maxillary sinus and cyst cavity were observed.

12 cases of radicular cysts, 10 cases of dentigerous cysts, and 3 cases of keratocystic odontogenic tumor were diagnosed according to pathological examination. The appearance of the maxillary sinus were completely restored and the cyst disappeared totally in 7 cases after the first 3 months, and then after the next 9-12 months, the other 18 cases had the appearance of maxillary sinus completely or basically restored with a following enucleation of cysts. All patients were followed up for 1-5 years, and no recurrence was observed.

To treat large maxillary cystic lesions by decompression is effective to conserve the morphology and function of maxillary sinus, and it is a simple surgical approach with less damage and complications.