Use of a Dental Vibration Tool to Reduce Pain From Digital Blocks: A Randomized Controlled Trial

The infiltration of local anesthetic is consistently described as painful by patients. Vibration anesthesia has been studied in the dental literature as a promising tool to alleviate the pain from dental nerve blocks. Many of these studies used a specific device, the DentalVibe. To date, there have not been any studies applying this technology to digital blocks of the hand in human subjects. We hypothesized that the use of microvibratory stimulation during digital blocks of the hand would decrease pain reported by patients.

This was a randomized controlled trial of consenting adult emergency department patients who received digital block anesthesia for hand digit therapy when study authors were present. The study period was 24 months at an academic emergency department. A sample size of 50 injections (25 subjects) was necessary for a power of 80% to detect a mean difference of 2 (SD, 2.5) on the pain scale. A 2-sided dorsal injection approach was used for digital blocks. Subjects were randomized to either intervention (vibration) for the first injection or sham (device off). Both intervention and sham were held in place for 5 seconds prior to and during injection. Subjects were given 2 mL of 1% lidocaine and asked to rate the injection pain on a 1- to 10-point scale. This process was then repeated. Mean pain scores were compared using paired t tests. Our primary outcome was the difference in mean injection pain score between sham versus intervention groups.

There were 25 patients in the study group (mean age, 35.52 years [range, 18-58 years]; 8 females; 11 non-Hispanic white). The mean injection pain score in the sham group was 4.28 (95% confidence interval [CI], 3.14-5.42), and in the intervention group, the mean pain score was 2.52 (95% CI, 1.62-3.42). For the primary outcome, the mean injection pain score difference between the sham and intervention groups across all subjects was 1.76 (95% CI, 0.49-3.03; P = 0.009). The mean injection pain score differences were similar across groups: females versus males (0.24; 95% CI, -2.31 to 2.79; P = 0.85), non-Hispanic whites versus other races (0.76; 95% CI, -1.78 to 3.29; P = 0.54), intervention first versus sham first (-0.43; 95% CI, -3.25 to 2.40; P = 0.75).

Our results show a statistically significant difference in mean injection pain score during digital block of the hand when the DentalVibe device is used for vibration anesthesia. Larger studies are warranted to confirm our findings.