Do length and gauge of dental needle affect success in performing an inferior alveolar nerve block during extraction of adult mandibular molars? A prospective, randomized observer-blind, clinical trial.

Abstract

Association between length and gauge of dental needle and success rate and pain perception during an inferior alveolar nerve block (IANB) has not been investigated using a randomized clinical trial (RCT). This RCT aimed to compare the success rate of IANB and perceived pain using 27- or 30-gauge needles for the extraction of adult mandibular molars. A prospective RCT was conducted on two hundred and twelve adult patients requiring extraction of mandibular molars using standard methods as described by Malamed with 1.8ml of 2% lidocaine with 1:80,000 adrenaline. One hundred six patients received IANB using 27-gauge needles (32mm × 0.2mm) and one hundred six patients received IANB using 30-gauge needles (25mm × 0.15mm). Predictor variables were 27-gauge and short and 30-gauge. Outcome variables were the success rate of IANB and pain perception during injection using a visual analogue scale. There was a highly significantly increase in the success of IANB using 27-gauge needle (95.28%) versus 30-gauge needle (41.51%) (P = 0.001). There was a significant increase in pain perception for patients who received IANB by shorter and thinner needle (30-gauge) when compared to the long and thicker needle (27-gauge). This RCT demonstrated that 27-gauge needle seems to be associated with a higher success rate of IANB and lower pain perception during injection when compared to 30-gauge needle in the extraction of adult mandibular molars when compared to 30-gauge needles. For adult patients, when thickness of soft tissue to be penetrated is essential to achieve bony contact, long or large gauge dental needle is preferred to get a higher success rate of IANB with less pain perception during injection.