Randomised controlled trial of a microneedle patch with a topical anaesthetic for relieving the pain of dental injections.

Objectives: To determine whether a microneedle patch combined with 5% topical lidocaine reduces dental injection pain more than a patch without microneedles combined with 5% topical lidocaine.

Methods: This proof of principle randomised, two-treatment, double-blind, crossover split-unit design study in 16 healthy participants investigated levels of perceived pain from 3 increasing pain provoking challenges, when topical 5% lidocaine dental gel was applied to the oral mucosa with a microneedle patch and a patch with no microneedles, prior to infiltration with local anaesthesia on 2 visits. Pain was assessed by visual analogue scale (VAS) and 4-point verbal rating scale (VRS).

Results: 15 participants completed the study. Mean pain scores, lower at buccal sites, increased in both groups across challenges 1-3: Test palatal 5.1, 11.9, 26.8; buccal 0.7, 2.8, 18.3; Control palatal 12.3, 18.7, 39.5; buccal 4.0, 6.9, 30.6. The microneedle patch plus lidocaine significantly lowered VAS pain scores at both sites for all challenges, the biggest mean difference seen palatally after challenge 3 (12.7, p < 0.001). VRS pain scores were also significantly reduced for test compared to control for all 3 challenges (p = 0.014). Buccal scores favoured the microneedle patch, significantly for pain challenge 3 (p = 0.025). No adverse events occurred.

Conclusions: Prior oral application of a microneedle patch combined with 5% topical lidocaine gel reduced the pain experienced from dental infiltration. Microneedle patch use in the dental setting offers the prospect of improving degree and depth of anaesthesia from topically applied anaesthetic gel, without itself causing any pain.

Clinical Significance: Dental injections are associated with fear and anxiety. Application of a microneedle patch, combined with topical anaesthetic, to the oral mucosa prior to delivery of the injection reduces the pain from this dental procedure. This novel technique may allay patients' apprehension of local anaesthesia and improve quality of life outcomes.