Research summary · Field experiment · 2010
Orange and apple scents in large dental clinics: no effect on anxiety
When researchers repeated the orange-scent studies in three large dental clinics in the Netherlands, and added an apple scent, neither scent changed patients’ anxiety, mood or pain while they waited. Most patients did not notice anything different about the smell of the room.
Reviewed by Simon Faure-Field · 8 October 2026 · Checked against the full text
Part of our evidence review: Does scent reduce anxiety in dental and medical waiting rooms?
At a glance
Key findings
- 219patients aged 18 to 81 in three large dental clinics.
- No effectof orange or apple scent on anxiety, mood or pain.
- 4.7 / 9average perceived scent strength, set with pilot patients.
The study
Citation and study details
Citation: Toet, A., Smeets, M. A. M., van Dijk, E., Dijkstra, D., & van den Reijen, L. (2010). Effects of pleasant ambient fragrances on dental fear: Comparing apples and oranges. Chemosensory Perception, 3(3), 182–189.
Read the original: doi.org/10.1007/s12078-010-9078-9
- Study typeField experimentIndependent replication
- Sample219 dental patients117 men, 102 women, aged 18–81
- SettingThree large dental clinicsRotterdam area, 70–80 patients a day each
- Evidence gradeA: direct field evidenceReal patients before real treatment
Method
What the researchers did
The researchers repeated the earlier orange-scent design in large clinics, and added apple as a second pleasant scent.
The study ran in the waiting rooms of three large dental clinics in the Rotterdam area, each seeing 70 to 80 patients a day. Each waiting room had orange scent, apple scent and no scent on different days over three weeks, in counterbalanced order. In total, 81 patients waited with orange, 69 with apple and the rest with no scent.
Two hidden electric dispensers in each waiting room nebulised the oil for 10 seconds every 2 minutes, starting about half an hour before the first patients arrived; in the control condition they nebulised water. Before the study, the researchers adjusted the dispensers until pilot patients rated the scent at a moderate strength, averaging 4.7 on a 9-point scale. Patients then completed a Dutch version of the State-Trait Anxiety Inventory, a short Profile of Mood States and a pain rating.
Results
What they found
Neither scent made any measurable difference, and the effect sizes were very small.
There was no significant difference in anxiety, mood or pain between patients who waited with orange, with apple or with no scent. The authors note that the effects were not only non-significant but also very small.
The result held across the three clinics and across the treatment patients were expecting, from check-ups to root canal treatment. Women were in a more positive mood than men overall, but scent made no difference for either.
Most patients did not rate the smell of the waiting room as different from other waiting rooms they had been in, which the authors read as the scent not being consciously noticed.
Limitations
Limitations
A clear null result, but at a deliberately moderate scent strength in busy clinics.
The scent was set at a moderate strength, and most patients did not consciously notice it. A stronger, more noticeable scent might have produced a different result. Patients in the apple group were younger on average than those in the no-scent group, although the authors controlled for age in their analysis.
The authors suggest two explanations: citrus scents can be stimulating as well as calming, and the two effects may cancel out; and the constant coming and going in a large clinic may itself distract patients, leaving less anxiety for a scent to reduce.
A note on the evidence
How strong is this evidence?
Strong as a counterweight: a careful, independent replication that found nothing.
This is the main independent test of the earlier orange-scent findings, and it was larger than the first of them. Its null result does not show that scent never helps in dental settings, but it does show the effect is not automatic: the setting, the scent and whether patients notice it all appear to matter.
For commercial spaces
What it means for commercial spaces
For a large, busy clinic, this study is a caution against assuming a fruity scent will calm patients. If a practice wants to use scent for comfort, the evidence from smaller practices favours a calming scent such as lavender over citrus, at a strength patients can actually notice. Practices should treat the result as a reason to test and ask patients, not as a reason to assume either success or failure.
Scent Swirl supplies ambient scenting for dental practices. See how scenting works in dental clinics →
How to cite this summary
Scent Swirl. (2026). Summary of Toet et al. (2010), Effects of pleasant ambient fragrances on dental fear: Comparing apples and oranges. Scent Research Library. https://scentswirl.com/research/toet-2010-orange-apple-dental-anxiety/ (last reviewed 8 October 2026 by Simon Faure-Field).
This summary has been checked against the full paper. If you spot an error or know of a study we should add, we would like to hear from you.
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