Preventive and therapeutic effects of semiconductor laser on pain in root canal treatment

This study aimed to evaluate the preventive and therapeutic effects of semiconductor laser on postoperative pain in root canal treatment and to compare the clinical efficacy of different laser application methods.

A total of 202 patients requiring root canal treatment at our hospital's dental department from January to December 2024 were selected and randomly divided into experimental and Control groups using a random number table. The Control group received conventional root canal treatment (58 cases); the experimental group received 810 nm semiconductor laser-assisted treatment based on conventional root canal therapy and was further divided into three subgroups according to different laser application methods: laser-activated irrigation group (LAI group, 48 cases), low-level laser therapy group (LLLT group, 48 cases), and combined application group (Combined group, 48 cases). The LAI group used laser as a root canal irrigation activation system; the LLLT group applied laser irradiation to the buccal and palatal mucosa externally; the Combined group applied both methods simultaneously. All patients received root canal treatment completed in a single visit, and 197 patients completed the 14-day follow-up. Visual Analogue Scale (VAS) was used to assess the patients' pain levels at 1, 2, 3, 7, and 14 days after the procedure, and the use of analgesics was recorded.

Within 14 days after treatment, there were statistically significant differences in the mean VAS scores among the four groups (P < 0.05). The Control group had the highest pain scores, while the Combined group had the lowest. On the first day after treatment, the VAS scores of all experimental subgroups were significantly lower than the Control group (P < 0.001), with the LLLT group showing the best immediate pain relief effect. On days 2-3 after treatment, there was no significant difference in pain scores between the LAI and LLLT groups, but both were better than the Control group (P < 0.001). On day 7 after treatment, the Combined group had the most long-lasting analgesic effect, showing a significant difference compared to the Control group. By day 14, the differences among groups were no longer statistically significant (P > 0.05). Regarding analgesic use, the experimental groups required significantly less medication than the Control group (P < 0.001), with the Combined group using the least (0.53 ± 0.74 tablets). Moreover, multivariate analysis found that the size of periapical lesions, preoperative pain level, and laser treatment protocol were the main factors affecting postoperative pain.

Semiconductor laser can effectively reduce postoperative pain after root canal treatment and improve patient comfort. The combined application of laser-activated irrigation and low-level laser therapy techniques is the optimal pain prevention and control protocol, which can continuously provide analgesic effects for 14 days after treatment. As an adjunctive treatment, semiconductor laser effectively reduces discomfort in root canal treatment by enhancing root canal disinfection and promoting inflammatory tissue repair. This study provides scientific evidence for the rational application of semiconductor laser in clinical root canal treatment, which is of great significance for improving the success rate and patient satisfaction of root canal treatment.