The effect of chronic periodontal disease on human jaw muscles: a pilot study using computed tomography

Patients with chronic periodontal disease sometimes complain of difficulty in masticating hard foods. Computed tomography (CT) was used to investigate the cross-sectional area (CSA) and density of the masseter and medial pterygoid muscles in a pilot study of 12 healthy female subjects aged 30-39 years. Six subjects (the 'diseased' group) had suffered from chronic periodontal disease and had, on average, 40% bone loss. Their disease had been treated by scaling and root planning and had remained clinically stable for at least 6 months before their inclusion in the study. The six age-matched 'control' subjects had no history of periodontal disease. All bone-loss measurements were evaluated as a percentage of root length. At defined scan planes, sections of both muscles were readily identified. Results from the 'diseased' group as compared with the 'control' group revealed that in the former the CSA of masseter and medial pterygoid was reduced significantly by 25% and 10%, respectively. There were no significant differences in the X-ray density of both muscles between the two groups, which indicated a similar fibro-fatty content. These findings indicate a reduction in the masticatory force that may be utilized by patients with reduced periodontal support and may help explain their masticatory difficulties.