Does Sleep Bruxism Enlarge Occlusal Contact Area in Adolescents?

Objectives: Sleep bruxism may have destructive effect on oral function. It is difficult to evaluate the prevalence of this nocturnal oral habit. Since one of the typical signs of sleep bruxism is excessive attrition, wideness of occlusal contact area could provide information for the assessment of sleep bruxism. Thus, the purpose of this research is to investigate the relationship between awareness of sleep bruxism and occlusal contact area in adolescents.
Methods: Thirty-two dental students (20 males and 12 females, 23.0±1.7 years old) belonging to Tokushima University, School of Dentistry participated in this research as subjects. None had full veneer restoration, malocclusion, and missing teeth except for the third molar. Occlusal registration record at maximum intercuspation was taken with blue silicone impression material and the width of the occlusal contact area was evaluated using BITEEYE BE-I (GC Corp., Tokyo, Japan). Questionnaire survey involving six questions on awareness of sleep bruxism was performed and severity of sleep bruxism in each subject was scored. Six months after the first investigation, the same procedure was performed for all subjects and average values in each investigation were used for analysis.
Results: Average occlusal contacts area was 29.6mm² for male and 21.7mm² for female subjects. A significant difference was found between male and female subjects in the width of the area (p=0.0307, Mann-Whitney U test), but the bruxism scores did not exhibit any gender difference. Correlation analysis between occlusal contact area and bruxism score exhibited significant positive correlation in female subjects (P=0.0408, Spearman's rank correlation coefficient), while no correlation was seen in the male subjects.
Conclusions: Results of this study indicate that large occlusal contact area in female adolescents may cause higher risk of sleep bruxism.