 The study was conducted as a prospective randomized comparative clinical study at the Department of Oral and Maxillofacial Surgery, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou and included 60 patients who needed surgical removal of a single impacted mandibular third molar under local anaesthesia. The study included 37 male and 13 female with age ranging from 20 to 40 years. Ethical approval was obtained from the Institutional Ethics Committee of Guanghua School of Stomatology, Sun Yat-sen University prior to the beginning of the study. The signed consent form obtained from all the patients after explaining the risks and benefits of the surgical procedure. 