The effect of oral analgesic premedication on the success rate of inferior alveolar nerve block for teeth with irreversible pulpitis: A randomized clinical trial

Objective: This study aimed to evaluate the effect of different premedication protocols on the success rate of the inferior alveolar nerve block (IANB) technique in mandibular molars with irreversible pulpitis.Methods: Two hundred and ten participants were randomly assigned into three groups (n=۷۰) and received one of the following premedications ۳۰ minutes before IANB injection: dexamethasone, pharmapain (containing acetaminophen, ibuprofen, and caffeine), and a placebo lactose capsule. Pain severity was evaluated with the Heft–Parker visual analog scale (VAS) before and ۱۵ minutes after the injection, during dentin removal, and when inserting files into the root canal. The IANB injection was considered successful if VAS values after ۱۵ minutes implied no pain or mild pain.Results:  IANB success rates were comparable in the dexamethasone (۵۱.۴%), pharmapain (۵۵.۷%), and placebo (۴۱.۴%) groups (P=۰.۲۲۲). Pain severity at baseline, ۱۵ minutes post-injection, and during dentin removal was comparable among the groups (P>۰.۰۵). However, when inserting endodontic files, the mean pain severity in the pharmapain group was significantly higher than the dexamethasone group (۱۰.۲۷ ± ۱.۷۱ versus ۷.۳۸ ± ۲.۲۴; P=۰.۰۰۲). No significant difference was observed between the placebo with any of the study groups (P>۰.۰۵).Conclusions: Premedication with pharmapain (an anti-inflammatory agent) or dexamethasone (a corticosteroid) does not enhance the success rate of the IANB technique in mandibular molars with irreversible pulpitis compared to placebo. However, the use of dexamethasone was significantly more effective than pharmapain in reducing pain severity at inserting endodontic files.