A prospective, randomized single-blind evaluation of effect of injection speed on anesthetic efficacy of inferior alveolar nerve block in patients with symptomatic irreversible pulpitis.

INTRODUCTION

Speed of injection may affect the solution spread in the pterygomandibular space. It was hypothesized that speed of injection will affect the anesthetic efficacy of inferior alveolar nerve block (IANB) in patients with symptomatic irreversible pulpitis.

METHODS

Fifty-nine adult volunteers who were actively experiencing pain participated in this prospective, randomized, single-blind study. The patients were divided into 2 groups on a random basis and received either slow or rapid IANB with 3.6 mL of 2% lidocaine with 1:200,000 epinephrine. Endodontic access preparation was initiated after 15 minutes of the initial IANB. Pain during treatment was recorded by using the Heft-Parker visual analogue scale. The primary outcome measure, and the definition of success, was the ability to undertake pulp access and canal instrumentation with no or mild pain (Heft-Parker visual analog scale score < 55 mm). Secondary outcome measure was the solution deposition pain. Statistical analysis was performed by using Mann-Whitney U test and χ(2) test.

RESULTS

Slow and rapid injections gave 43% and 51% success rates, respectively. The difference was statistically insignificant. Slow injections produced less solution deposition pain than rapid injections.

CONCLUSIONS

Rate of injection has no effect on anesthetic success of IANB, but slow injections were more comfortable than rapid injections.