Efficacy of liposome-encapsulated mepivacaine for infiltrative anesthesia in volunteers

This blinded crossover study evaluated the efficacy and pain sensitivity evoked by a previously reported liposome-encapsulated mepivacaine formulation (). Thirty healthy volunteers received an intraoral injection (1.8?mL), at four different sessions, of the following formulations: 2% mepivacaine with 1:100,000 epinephrine (MVC_2%EPI), 3% mepivacaine (MVC_3%), and 2 and 3% liposome-encapsulated mepivacaine (MVC_2%LUV and MVC_3%LUV). Latency period and duration of anesthesia were assessed by an electrical pulp tester and injection discomfort by a visual analog scale (VAS). Data were analyzed with Tukey-Kramer and Friedman tests (P?P?>?0.05). The duration of anesthesia after the injection of MVC_3%LUV was higher than the one obtained after the infiltration of MVC_2%LUV and of MVC_3% (P?3% did not differ from the one obtained with MVC_2%LUV (P?>?0.05). MVC_3%LUV showed lower VAS median values than MVC_2%EPI (P?3%. MVC_2%LUV was able to produce a similar duration of anesthesia as the 3% commercial formulation, despite the 50% decrease in the anesthetic concentration. Thus, the encapsulation of mepivacaine increased the duration of anesthesia and reduced the injection discomfort caused by vasoconstrictor-associated formulations in healthy volunteers.