Objective To investigate the main distribution and composition of microorganisms in the therapy area at the department of oral medicine.

SETTING and MATERIALS:Research was carried out in the Department of Oral Biolo gy, and Department of Nuclear Medicine of Xijing Hospital, Fourth Military Medical University.

Department of Oral and Craniomaxillofacial Science, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine; Shanghai Key Laboratory of Stomatology.