Objective To compare the clinical efficacy of the infiltration anesthesia with primacaine and the nerve blocking anesthesia with lidocaine for microport extraction of impacted lower third molar. Methods 104 chosen patients had both sides of impacted lower third molars extracted in this study. Patients were given local anesthesia with either primacaine or lidocaine randomly at each side, and then underwent microport extraction. Clinical factors including effective proportion（EP）, effecting time point（ETP）, visual analogue scale of pain（VASp）, alteration of systolic pressures（ ASP） and analgesia duration（AD） were evaluated statistically by means of paired t-test. Results The EP of experimental group was higher than the control group（P=0.024）. The ETP of soft tissue and alveoli-dental pulp was （1.04±0.21）, （2.44±2.60）min in the experimental group, and much earlier than that of the control group（P=0.002, P=0.032）. The VASp and ASP of experimental group were lower than the control group（P=0.041, P=0.018）. AD was （103.6±35.5）min, and higher than the control group（P=0.04）. Conclusion The infiltration anesthesia with primacaine has been proven to be a easier, reliable and quick-acting method. We suggest it an alternative method replacing the 2% lidocaine blocking during microport extraction of impacted lower third molar.
