A Study of Anesthesia

A painful truth in dentistry today is that for most dental procedures, local anesthesia is truly effective only when injected. The insertion of the needle and the injection of the anesthetic fluid itself can cause discomfort, and for decades dentists have been using topical anesthesia to reduce this. They have also tried to use finer-gauge needles in the belief that they cause less pain. As topical anesthesia can be useful for minimizing the pain associated with needle insertion, it has not been proven to address the pain of the actual injection of the solution. 

A recent study in Anesthesia Progress examined the effectiveness of topical anesthesia in reducing pain associated with needle insertion separately from the pain associated with injection of the anesthetic. Results were investigated after different intervals (2, 5, and 10 minutes) to determine the time for optimal efficacy of the topical anesthetic. In a double-blind, placebo-controlled study, re­sponses from 85 people showed that the topical anesthetic was statistically and significantly more effective compared to the placebo for reducing the pain caused by needle insertion alone at all time points. Yet it had no effect on perceived pain intensity associated with injection of the local anesthetic solution at any of the time intervals. At all time lengths, patients reported the same degree of pain from anesthetic solution injections in topically anesthetize and placebo locations. Therefore, the minimum 2-minute periods appear to be sufficient for the topical anesthetic application, since a 5- or 10-minute delay has no added benefit in reducing the pain of needle insertion. The reported pain intensity levels were not associated with differences in the subjects’ age, gender, weight, or heart rate.