Effect of intrapulpal cryoanesthesia on intraoperative pain during root canal treatment in mandibular molars: a double blinded randomized control trial

To evaluate the impact of cooling the anesthetic solution prior to administering intra-pulpal anesthesia on the severity of intraoperative pain during root canal treatment in mandibular molars with symptomatic irreversible pulpitis and symptomatic apical periodontitis. Forty patients with mandibular molars diagnosed with symptomatic irreversible pulpitis and symptomatic apical periodontitis received root canal treatment by a single operator following a standardized technique. Patients received an intra-pulpal injection of 2% lidocaine with 1:100,000 epinephrine and were randomly and equally assigned to two groups based on the temperature of the cartridge. The room-temperature group received a cartridge that was kept at 25-26 °C while for the cryoanesthesia group, the cartridge was cooled to a temperature of 4-5 °C. The HP-VAS scale was used to evaluate the patients' preoperative, intraoperative pre-injection, and intraoperative post-injection pain scores. The success rate was calculated by the lack of additional anesthesia following the intra-pulpal injection. Pain scores were statistically analyzed at a significance level of 0.05. Both the cryoanesthesia and the room-temperature groups were effective in significantly reducing the severity of intraoperative pain, where p < 0.001 for both groups. The cryoanesthesia group showed a 100% success rate compared to 80% for the room-temperature group without a statistically significant difference (p = 0.106). The difference in pain score reduction in both groups, however, was statistically significant (p < 0.001). Cryoanesthesia yielded more profound pulpal anesthesia compared to the room temperature intra-pulpal injection.