Abstract: PURPOSE: To explore the clinical effect of ultrasonic irrigation combined with chlorhexidine in root canal treatment of pulpitis. METHODS: A total of 120 patients with pulpitis treated with root canal therapy were randomly divided into a study group (n=60, 72 affected teeth) and a control group (n=60, 70 affected teeth). During root canal preparation, the study group was treated with chlorhexidine combined with ultrasonic irrigation, while the control group was treated with chlorhexidine conventional irrigation. The bacterial count and endotoxin content in the root canal before and after root canal preparation were compared between the two groups, as well as the endodontic inter-appointment pain (EIAP), lateral branch root canal filling rate, and degree of tooth pain after root canal treatment. The success rate of treatment was statistically analyzed after one-year follow-up. Statistical analysis was performed with SPSS 19.0 software package. RESULTS: After root canal preparation, the number of colonies in experimental group and control group was significantly decreased compared with that before root canal preparation(P<0.05), and the number of colonies in experimental group was significantly lower than that in control group(P<0.05). After root canal preparation, endotoxin levels in experimental group and control group were significantly lower than those before root canal preparation(P<0.05), and the level in experimental group was significantly lower than that in control group(P<0.05). The lateral branch root canal filling rate in the study group and the control group was 29.17% and 11.43%, respectively, with significant difference between the groups(P<0.05). The incidence of EIAP was 4.17% and 14.29%, respectively, with significant difference between the two groups(P<0.05). At 48 hours after surgery, the visual analogue score (VAS) of the study group and the control group was (2.74±0.61) and (3.29±0.68), respectively, which were significantly lower than at before surgery(P<0.05). There was a significant difference in VAS score between the two groups 48 hours after surgery(P<0.05). One week after surgery, the VAS score in the study group and the control group was (1.52±0.34) and (1.81±0.42), respectively, significantly lower than that before and 48 hours after surgery(P<0.05). There was a significant difference in VAS score between the two groups at one week after surgery (P<0.05). The successful rate of treatment in the control group was 84.62%, and 95.71% in the study group, with a significant difference between the two groups(P<0.05). CONCLUSIONS: The application of ultrasonic irrigation combined with chlorhexidine in the treatment of pulpitis root canals can help reduce the level of bacteria and endotoxin after root canal preparation, alleviate the degree of postoperative tooth pain, and improve the filling rate of lateral branch root canals, with superior curative effects.

Key words: Pulpitis, Root canal therapy, Ultrasonic washing, Chlorhexidine