Does the aroma of a patient’s preferred dental topical anaesthetic affect anxiety, fear, and autonomic nervous system activity prior to dental local anaesthesia? A randomized trial

Abstract

Aromas are believed to have powerful effects on emotional states in humans. Treatment with dental local anaesthesia (DLA) is a mentally stressful and fearful experience for many patients. We investigated the effect of using a topical anaesthetic with a patient-preferred aroma prior to DLA on anxiety, fear, and autonomic nervous system activity (ANSA). Anxiety and fear were assessed in 68 healthy volunteers using both a modified Japanese translation of Spielberger's State–Trait Anxiety Inventory (STAI-s) and a visual analogue scale (VAS). ANSA was assessed by heart-rate variability (HRV) analysis, which yields normalized low-frequency (%LF) and high-frequency (%HF) components. These parameters were assessed at baseline and immediately prior to DLA. The volunteers randomly received either a topical anaesthetic without an aroma (non-aroma group) or one with a patient-selected aroma (aroma group) prior to DLA. The data were statistically analysed with two-way analysis of variance (ANOVA) and post hoc t-tests. The STAI-s scores in the non-aroma group prior to DLA were significantly higher than the baseline scores. In contrast, the STAI-s scores in the aroma group prior to DLA were not significantly higher than the baseline scores. On the other hand, the VAS scores in both the non-aroma group and the aroma group were significantly higher prior to DLA than the baseline scores. Patients do not experience increased anxiety when using dental topical anaesthetic with their preferred aroma prior to DLA.