2011 Volume 3 Issue 2 Pages 144-153
Purpose: The present study aimed to evaluate the discomfort of mouth guards (MGs) by using two objective physiological measures.
Methods: Fifteen healthy male students (age, 19-28 years) participated. We recorded salivary activity of α-amylase (enzyme activity) and heart rate variability by measuring of R-R intervals. Subjective questionnaire assessments for their comfort were also measured by visual analog scale method. Each parameter was recorded while subjects wore large, middle, or small MGs. The large MG was the covered palate type. We cut along the 4-mm outer cervical line to make the medium MG, and along the cervical line to make the small MG. The three sets of parameters were assessed on consecutive 2 days. Salivary α-amylase was measured four times for each MG type: immediately before inserting the MG, 3 min after insertion, immediately after removal, and 3 min after removal. Heart rate variabilities [HF: high-frequency component, LF (low-frequency component)/(HF+LF) × 100] were measured during two periods for each MG type: 90 sec period immediately before insertion and 60 sec period during wear. After removing each MG, participants answered a questionnaire consisting of five items: ease of breathing, dry mouth, sensation of a foreign object, usability during sports and tongue sensation.
Results: Salivary α-amylase levels increased significantly with all types of MG, particularly for the large MG during the wear and immediately after removal. In HF, there was no significant differences between pre-insertion and insertion for any MGs. However, LF/(HF+LF) × 100 increased while participants wore any MGs. Especially, it for large MG was significantly higher than those for other two MGs. The questionnaires showed significant differences among the MG types. In particular, the large MG was more uncomfortable than the other two.
Conclusion: Our results suggest that small and middle MGs are more comfortable than large ones.
