Efficacy of 0.5M mannitol as an adjuvant to lidocaine and epinephrine for intra-oral nerve blocks - a split-mouth, randomized controlled trial

BACKGROUND: In dentistry operations, addition 0.5 M mannitol to lidocaine-epinephrine improves anesthesia efficacy. However, its effect on hemodynamic parameters and post-operative outcomes have not been evaluated. This study aimed to compare the efficacy, hemodynamic parameters, and post-operative outcomes of 2% lidocaine and 1:200,000 epinephrine, with or without 0.5 M mannitol, in intra-oral nerve blocks. MATERIALS AND METHODS: This prospective, randomized, controlled, triple-blind, split-mouth study included 25 patients who required intra-oral block for elective extraction of lower erupted teeth. The Test side (n = 25) received lidocaine-epinephrine-mannitol, while the Control side (n = 25) received lidocaine-epinephrine. The primary outcome measures were evaluated were onset and duration of anesthesia. The secondary outcome measures were pain (assessed with visual analogue scale [VAS] on day 0-3, and 7); hemodynamic parameters (including heart rate, systolic blood pressure [SBP], diastolic blood pressure [DBP], and oxygen saturation, assessed pre-, intra-, and post-operatively); and post-operative complications (swelling and trismus assessed on day 7). RESULTS: The Test side had a significantly early onset of action (p = 0.006) and delayed return of sensation (p = 0.001). On day 0, VAS score was significantly lower in the Test side (p = 0.017), with no difference at other intervals (p > 0.05). Post-operatively, mouth opening was significantly greater on the test side (p = 0.023), with no difference in post-operative swelling (p = 0.317). The control side had a significantly higher intra- (p = 0.018) and post-operative (p = 0.006) heart rate, with comparable SBP, DBP, and oxygen saturation. CONCLUSION: Lidocaine-epinephrine-mannitol formulation showed improved anesthetic efficacy, reduced pain on the day of procedure, stable hemodynamic parameters, and increased post-operative mouth opening. TRIAL REGISTRATION: CTRI/2022/10/046921 [Registered on: 31/10/2022].