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.

OBJECTIVE

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.

MATERIAL AND METHOD

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 1.8 ml of 2% lidocaine with 1:80,000 adrenaline. One hundred six patients received IANB using 27-gauge needles (32 mm × 0.2 mm) and one hundred six patients received IANB using 30-gauge needles (25 mm × 0.15 mm). 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.

RESULTS

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).

CONCLUSION

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.

CLINICAL RELEVANCE

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.