Effectiveness of Buffered Lidocaine With Sodium Bicarbonate Versus Conventional Lidocaine as Local Anesthetic Solutions for Pain Management in Pediatric Dentistry: A Randomized, Split-Mouth, Crossover, Double-Blind Clinical Trial

Abstract

OBJECTIVES: Managing injection pain is critical for pediatric patient cooperation. The clinical benefit of using 7.5 sodium bicarbonate-buffered lidocaine, compared to its unbuffered counterpart, has not been extensively studied in children using a controlled split-mouth design. Hence, this clinical trial aimed to compare the pain control efficacy of buffered versus conventional lidocaine in pediatric dentistry, assessing pain during injection, anesthetic depth, and anesthetic onset. MATERIAL AND METHODS: A randomized, split-mouth, crossover, double-blind clinical trial was conducted involving 53 healthy children referred to the Kerman Dental School. Children requiring local anesthesia for the same dental procedure on two molars of the same name in one jaw were randomly assigned to Group 1 (first session: conventional 2 lidocaine; second session: buffered 2 lidocaine with 7.5 sodium bicarbonate) and Group 2 (reverse sequence). The two sessions were separated by a 1‑week washout period. Pain during injection was assessed using the SEM (Sound, Eye, Motor) scale and the FPS-R (Facial Pain Scale-Revised), and pulse rate changes were monitored. The SEM scale also assessed both the anesthetic onset and depth. RESULTS: Buffered lidocaine resulted in significantly lower SEM scores during injection (a 17 reduction; Exp(beta) = 1.17, 95 CI 1.10, 1.23, p < 0.001) and faster anesthetic onset (a 6% improvement; Exp(beta) = 1.06, 95% CI 1.01, 1.11, p = 0.011) compared with conventional lidocaine. These improvements did not extend to subjective pain scores (FPS‑R), where no significant difference was observed. Pulse rate increased similarly after the injection of either local anesthetic formulation, with no treatment‑dependent hemodynamic effect. CONCLUSIONS: The administration of buffered lidocaine with 7.5% sodium bicarbonate significantly improved objective behavioral outcomes, as evidenced by lower SEM scores and a quicker onset, compared to conventional lidocaine. While these findings did not extend to subjective pain scores, the reduction in physical distress behaviors advocates for its clinical use in pediatric dental procedures. TRIAL REGISTRATION: IRCT20241119063775N1.