Clinical efficacy of 1 and 2% solutions of lidocaine.

Both I and 2% lidocaine solutions were clinically evaluated for effectiveness in the induction of profound local anesthesia in adolescents. This effectiveness was measured by the ability to extract healthy premolars without discomfort. In a cross-arch design using paired premolars the double-blind administration of 1% lidocaine was found to be as effective as 2% lidocaine in induction of local anesthesia. Statistical analyses indicated that failures in mandibular teeth were associated with female patients. The results suggest that 1% lidocaine may be considered for selective use in the young child patient to reduce the possibility of local anesthesia toxicity. This approach may be important when lidocaine is used in conjunction with sedative agents in cases where multiple quadrants require therapy. There have been documented reports of convulsive episodes and death following the administration of excessive quantities of local anesthetic agents to children for dental procedures (California Board of Dental Examiners 1978; Sanders et al. 1979; Malamed 1980). The magnitude of overdosage in these cases implies a lack of appreciation of dosage guidelines as well as a failure to adjust dosage for body weight in small children. There is a need in pediatric dentistry for a local anesthetic agent with greater margin of safety than the currently employed 2% solution. Early attempts to evaluate lidocaine objectively as a dental anesthetic were performed by measuring tooth response to graded electrical stimulation. Studies by Bjorn (1946) and Brynolf (1947) demonstrated that painless tooth preparation may be accomplished in anesthetized teeth despite sensitivity to electric current. Bjorn and Huldt (1947) revealed that negative tooth response to electrical stimulation was achieved in 97.3% of cases anesthetized with 1% lidocaine and in 100% of cases anesthetized with 2% lidocaine when equipotent concentrations of epinephrine were employed. Historically, these findings appear to have paved the way for 2% lidocaine usage in dentistry. This small difference between the 1 and 2% concentrations, however, may not be significant clinically. Since toxicity increases commensurately with increasing concentration, a safer anesthetic technique for use in small children may be possible by employing a similar volume of a less concentrated solution. Although the concentrations of lidocaine recommended for most infiltrations and peripheral blocks for purposes of medical procedures in children range from 0.5 to 1% (Eather 1975), 2% solutions continue to be used for dental procedures despite little reported research to substantiate this concentration. The purpose of this pilot study was to evaluate the effectiveness of 1 and 2% lidocaine in obtaining local anesthesia for the extraction of healthy premolars in an adolescent patient population.