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.
Incidence of anesthesia in the central incisor. The graph depicts the percentage of subjects with no response to electric pulp tester (EPT) at the maximum setting for the 2 anesthetic formulations. The dotted line represents dexmedetomidine hydrochloride + lidocaine (DL) and the solid line represents lidocaine (L) alone.
Incidence of anesthesia in the first molar. The graph depicts the percentage of subjects with no response to electric pulp tester (EPT) at the maximum setting for the 2 anesthetic formulations. The dotted line represents dexmedetomidine hydrochloride + lidocaine (DL) and the solid line represents lidocaine (L) alone.
Change in blood pressure caused by the 2 anesthetic formulations. There was a decrease in systolic and diastolic blood pressure when dexmedetomidine hydrochloride + lidocaine (DL) was administered. The lower set of lines represents diastolic blood pressure, whereas the upper set represents systolic blood pressure. The dotted line represents DL and the solid line represents lidocaine (L) alone. * indicates p < .05.
Change in heart rate caused by the 2 anesthetic formulations. The heart rate in subjects administered dexmedetomidine hydrochloride + lidocaine (DL) was significantly decreased as compared to that in subjects administered only lidocaine (L). The dotted line represents DL and the solid line represents L alone. * indicates p < .05.
Change in bispectral index (BIS) values caused by the 2 anesthetic formulations. BIS significantly decreased in subjects administered dexmedetomidine hydrochloride + lidocaine (DL) compared to that in subjects administered lidocaine (L) alone. The dotted line represents DL and the solid line represents L alone. * indicates p < .05.
Contributor Notes