Inclusion Criteria:  -Medical records of patients who were diagnosed with multicystic ameloblastoma (MA) or unicystic ameloblastoma (UA) by routine pathology were collected from January 2010 to December 2017 in Ninth People's Hospital of Shanghai JiaoTong University Medical College.  Exclusion Criteria:  followed up less than 3 years For FDSC group, fenestration decompression failed recurrent ameloblastoma received other type of surgery;