Dexmedetomidine Enhances the Pulpal Anesthetic Effect of Lidocaine: A Pilot Study

Dexmedetomidine hydrochloride (DEX) demonstrates analgesic, sedative, and hypotensive effects. DEX may also enhance the effect of local anesthetics used in the oral cavity, although this has not been well established in combination with lidocaine. We conducted a single-blind crossover study in 8 healthy volunteers to investigate whether DEX enhances the anesthetic effect of lidocaine in the oral cavity. DEX or DEX + lidocaine was injected into the labial gingiva corresponding to the root apex of the maxillary left central incisor and into the buccal gingiva corresponding to the root apex of the mandibular right first molar. Pain threshold, blood pressure, pulse rate, oxygen saturation, and bispectral index were measured 5 minutes after treatment and at 10-minute intervals for 60 minutes. DEX + lidocaine caused pulpal anesthesia in more subjects than lidocaine alone; this difference was significant for both central incisors and first molars up to 40 minutes after treatment. Following DEX + lidocaine treatment, blood pressure and bispectral index were significantly reduced at several time points, and pulse rate significantly reduced at all time points. Neither treatment caused changes in oxygen saturation. In conclusion, administering DEX with lidocaine for dental local anesthesia caused sedation and enhanced local anesthesia compared to lidocaine alone.