Breathing Biofeedback During Dental Surgery (Wong 2025)

What was investigated?

Researchers at the University of Hong Kong investigated whether real-time breathing biofeedback can reduce anxiety and physiological stress responses in patients during tooth extraction under local anesthesia. The central question was whether situational anxiety during the dental procedure can be measurably influenced through visual feedback of one’s own breathing parameters in real time. This is one of the first randomized controlled trials on the use of breathing biofeedback in dentistry.

Methods

62 patients were randomized and 60 completed the study (30 per group). Included were adults (18+) requiring non-surgical tooth extraction under local anesthesia. Measurements were taken preoperatively, perioperatively, and postoperatively. The biofeedback group received real-time feedback of their breathing parameters through Epson Moverio BT-30C smart glasses, where a color-coded symbol indicated breathing coherence (Red = incoherent breathing, Green = deep, coherent breathing). The control group wore identical hardware but received no feedback on the glasses. Measurement instruments included respiratory rate and amplitude, pulse rate, and validated anxiety scales (VAS, STAI, MDAS, DFS).

Results

The researchers found the following statistically significant differences in favor of the biofeedback group:

During the procedure (perioperative):

• Significantly lower respiratory rate (mean difference: -2.75 breaths/min; p = 0.03)
• Higher breathing regularity (+5.63 percentage points; p = 0.035)
• Higher respiratory amplitude (+48.83 units; p = 0.005)

After the procedure (postoperative):

• Greater decrease in pulse rate (-3.61 bpm; p = 0.030)
• Significantly lower STAI-State anxiety scores (situational anxiety; p = 0.015)
• Significantly lower VAS anxiety scores immediately after the procedure (p = 0.002)

No significant differences were found for the dental-specific long-term anxiety measures MDAS and DFS. The authors interpret this by noting that deeply rooted dental anxiety (as a stable personality trait) is not substantially changed by a single biofeedback session — the intervention showed its effect specifically on situational anxiety during the procedure.

Significance

This study is the only published randomized controlled trial (RCT) to date in which the eSense Respiration was used as the primary measurement instrument in a clinical intervention study. It demonstrates the practical applicability of the sensor under real clinical conditions — in the treatment chair of a dental practice, with patients under acute stress, during a medical procedure.

The significant reduction in situational anxiety (STAI-State, VAS) and the improved respiratory parameters demonstrate that real-time breathing biofeedback with the eSense Respiration has a demonstrable effect on perioperative stress physiology. The study appeared in 2025 in the International Dental Journal, an internationally recognized dental medicine journal.