Pulpal anesthesia dependent on epinephrine dose in 2% lidocaine. A randomized controlled double-blind crossover study

We studied the discrepancy in the results published on the dependence of the duration of pulpal nerve anesthesia on the concentration of epinephrine in 2% lidocaine. The increase in pain threshold of the pulpal nerve was measured before and after injection of lidocaine alone and lidocaine with epinephrine concentrations of 1:200,000, 1:100,000, or 1:50,000 into the mucobuccal aspect adjacent to the apex of the maxillary right incisor. The study was done in a random manner with a double-blind crossover design. The pulpal nerve was stimulated with negative rectangular electrical pulses of up to -167 V with 100 Hz and a pulse width of 0.6 msec. The results show a relationship between the 1:200,000 and 1:100,000 epinephrine concentrations and the success and duration of anesthesia. The onset of anesthesia was independent of the catecholamine content of the solution.