Can Scent Ease Anxiety at the Dentist?

Could an orange or forest-like scent in a dental waiting room ease anxiety before treatment? The AROMA_dent study, published in 2024, diffused essential oils in four Berlin dental practices and examined patients’ anxiety and pain.

Of 515 participants, 486 who completed the primary assessment were analyzed. Overall, mean anxiety was lower in the scented conditions, but the difference was not statistically clear. The authors highlighted possible benefits for some patient groups and the atmosphere of dental practices. Let us examine which findings underpin that optimism.

Do individual essential oils and blends differ?

The study aimed to determine whether diffusing essential oils in dental practices affected immediate anxiety or pain during treatment. It also tested whether blends outperformed individual oils and whether forest-associated scents differed from citrus-associated scents.

The four scents were orange, Swiss pine, a citrus-centered blend called “Good Mood,” and a forest-themed blend called “Forest Walk.” These were compared with a control condition without scent diffusion. The expectation that forest scents would be calming was itself treated as a hypothesis to test.

Conditions changed by practice-week, not by individual patient

Each practice switched scent conditions weekly in a randomized order. Patients experienced whichever condition was assigned to the week of their appointment. Since patients attending the same practice in the same week experienced the same scent, this was not a trial independently randomizing each patient. Randomizing groups in this way is called a cluster-randomized trial.

Scents were diffused in both waiting and treatment rooms. Although the abstract and some other passages label the control “water,” the detailed methods state that all devices were switched off during control weeks. This article follows that methods description in referring to a condition without scent diffusion.

The analysis included 95 patients in the control condition, 72 with orange, 110 with Good Mood, 100 with Swiss pine, and 109 with Forest Walk. The researchers used a cover story to conceal the main focus on scent, but could not completely hide whether a scent was present.

The main measure was state anxiety before treatment: how anxious a person felt at that moment. Patients completed the STAI-S questionnaire after arriving and being exposed to scent, with exposure before completion assumed to be about 10–20 minutes. This compared scores from patients attending under different conditions rather than measuring changes in the same patients before and after smelling the scent.

No clear anxiety reduction was demonstrated across all 486 patients

Mean state-anxiety scores were 40.7 in the control condition and 38.4 across the four scented conditions. Although the scented conditions were 2.3 points lower, p = 0.080 did not reach statistical significance. The standardized effect size was d = 0.21.

This means that the study did not establish a clear overall anxiety reduction with these methods and participants. A lower average alone does not prove an effect; conversely, failure to establish a difference does not show that every scent is ineffective in every situation.

Neither the hypothesis that blends outperform single oils nor the hypothesis that forest-associated scents outperform citrus-associated scents received statistical support. Pain during treatment also showed no clear difference. This trial therefore provides no basis for choosing a blend because it supposedly works more strongly, or a forest scent because it is supposedly better suited to dental anxiety.

How should the difference observed in women be interpreted?

The researchers conducted additional analyses by factors such as sex and general tendency toward anxiety. In a post-hoc analysis restricted to 296 women, state anxiety was lower in scented conditions, with p = 0.044. The authors emphasized this and results among people with higher trait anxiety as possibilities for future research.

However, the result in women came from an exploratory analysis after considering the overall findings. Examining many different subdivisions increases opportunities for chance differences. A difference in women but not in men does not by itself establish that effects differ by sex. It would be premature to say that scent reliably works for women or to present this result alone as the study’s overall conclusion.

For participants with higher trait anxiety, reported counts and means also differ between the abstract and the main text or tables. These figures should therefore not be adopted as definitive effect estimates, but treated as clues to test in a subsequent trial with a prespecified target population.

The challenges of studying real dental practices

The study aimed to recruit 750 participants, with 705 evaluable patients, but analyzed 486. The authors explain that staff shortages and reduced attendance during an infectious-disease outbreak hampered recruitment, reducing statistical power to detect differences. Insufficient numbers alone, however, do not establish that recruiting more participants would have revealed an effect.

There were only four practices, and room size, ventilation, and waiting times varied. FFP2 masks were mandatory during the study. Actual scent intensity and exposure duration likely differed between participants. Conducting research in real clinical settings was a strength, but also made scent delivery difficult to standardize.

Individual preferences were not incorporated into the conditions. The same forest scent might evoke pleasant memories for one person and be disliked by another. The study also could not distinguish effects of the oils themselves from effects of masking characteristic dental-practice odors. The authors see a need to examine such individual differences and psychological experiences more closely.

Questions remain about atmosphere and safety

Staff reported impressions such as an improved practice atmosphere and pleasant citrus scents. Drawing partly on these observations, the authors discussed scent as one possible component of a broader approach to anxiety. However, staff impressions are a different kind of information from questionnaire comparisons. They are not objective confirmation of a change in atmosphere or an effect on patients.

Although the paper reports no adverse events associated with essential-oil diffusion, its table of staff observations includes accounts of people finding the scent too strong or associating forest scents with headaches. Differences in reporting methods and the nature of these records mean that the findings cannot establish safety for everyone. Future tests should assess reactions in people who dislike the scents as well as those who find them pleasant.

The study received funding, oils, and equipment from PRIMAVERA, and equipment from HAAL ROSA. The paper states that neither company participated in study design, conduct, data interpretation, or writing.

Summary

In this analysis of 486 patients at four dental practices, mean anxiety was slightly lower in scented conditions, but the overall difference was not statistically clear. The findings also did not support superiority of blends or forest-associated scents, or pain reduction.

The authors identified scope to investigate scent and anxiety further, based on additional analyses in women and other groups and staff observations. Further work needs to consider actual scent exposure in practices, patients’ preferences and memories, and effects on people who dislike the scents. Scent may have a place in clinical environments, but this study did not show that it can replace established treatment for dental anxiety or pain.

References
Authors: Judith Czakert, Farid I. Kandil, Hiba Boujnah, Pantea Tavakolian, Sarah B. Blakeslee, Wiebke Stritter, Henrik Dommisch, Georg Seifert
Article: Scenting serenity: influence of essential-oil vaporization on dental anxiety – a cluster-randomized, controlled, single-blinded study (AROMA_dent)
Journal: Scientific Reports 14, 14143 (2024)
DOI: 10.1038/s41598-024-63657-w
Full original article: Scientific Reports article page / Open PDF at the German National Library
Rights: The original article is published under CC BY 4.0.