Posterior superior alveolar nerve blocks: a randomised controlled, double blind trial

Local anesthesia has been a boon for dentistry to allay the most common fear of pain among dental patients. Several techniques to achieve anesthesia for posterior maxillae have been advocated albeit with minor differences. We compared two techniques of posterior superior alveolar nerve block (PSANB), the one claimed to be "most accurate" to the one "most commonly used."

This study was conducted to assess and compare the efficacy as well as complications of "the straight needle technique" to that of "the bent needle technique" for PSANB.

We conducted a prospective, randomised, double blind study on 120 patients divided into two groups, using a 26-gauge, 38 mm long needle with 2 ml of 2 % lignocaine hydrochloride with 1:200,000 adrenaline solution. Objective symptoms were evaluated by a single investigator. Cold test using ice was used to evaluate the status of pulpal anesthesia. Data thus obtained was subjected to statistical analysis.

Out of the 120 blocks, 19 blocks failed. Statistical analysis found straight needle technique to be more successful than the bent needle technique (p = 0.002). Both the techniques were equally effective for the first molar region on both right and left side (p = 0.66 on right side and p = 0.20 on left side). However, in the second and third molar region technique A was more effective than B (p = 0.01) on right side only. On Left side, both techniques were equally effective (p = 0.08). Sensitivity of the cold test was 82 % which is quite high but the specificity was 68 % which seems to be falling in the above average range only. Positive predictive value of 75 and negative predictive value of 76 was observed. We did not encounter any complications in this study.

To the best of our knowledge, this is the first randomised controlled clinical study on PSANB techniques. This study suggests that the PSANB using the straight needle technique as advocated by Malamed [1] can be routinely and safely used to achieve anesthesia in the maxillary molar region and to great efficacy, with normal precautions.