Effects of inhalation sedation with nitrous oxide on intraoral senses

Objective The dental treatment such as local anesthetic injections are a common source of anxiety and fear during dental procedures. One of the causes of these anxiety and fear are regarded as taste and tactile sensory input. The purpose of this study was to investigate the effects of inhalation sedation with nitrous oxide (IS–N2O) on intraoral taste and tactile sensory input in human. Materials and methods We performed taste testing using electrogustometry and the filter paper disc test in the proglossis region, and precise tactile function testing using the Semmes-Weinstein monofilaments (SWM) test was performed on the mandibular incisor interdental gingival papilla of healthy male and female volunteers. Results On electrogustometry, the 50% IS-N2O threshold was significantly higher than those of other conditions (vs. room air [RA], 100% O2, Recovery, vs. 30% IS-N2O). In the filter paper disc test, the 30%/50% IS-N2O thresholds were significantly higher than those of other conditions (vs. RA, 100% O2, Recovery) for all tastes. However, no significant difference in the recognition threshold was noted between 30% IS-N2O and 50% IS-N2O. In the SWM test, the 30%/50% IS-N2O thresholds were significantly higher than those of other conditions (vs. RA, 100% O2, Recovery), but the 50% IS-N2O threshold was higher than the 30% IS-N2O threshold. Conclusion IS-N2O inhibit the input of taste and tactile sensations and may be an effective tool for patients undergoing dental procedures.