Purpose: This study aims to investigate the relationship between masticatory function and dysphagia in patients with myotonic dystrophy (MyD).
Methods: Eighteen MyD patients with an average age of 54.1 years (SD, 5.7 years) were enrolled as subjects of this study. They were divided into 2 groups: a non-dysphagia group (12 patients) that consumed ordinary rice along with an ordinary supplementary diet and a dysphagia group (6 patients) that consumed semisolid rice along with a chopped supplementary diet. The maximum bite force, activity in the temporal and masseter muscles during 1 chewing cycle, number of food items that were considered as easy to chew, and occlusal contact area were investigated, and the proportion of patients with anterior open bite was analyzed. The results obtained were compared between the groups.
Results: The maximum bite force in the dysphagia group was statistically much smaller than that in the non-dysphagia group (P=0.024). On the other hand, the masticatory muscle activity in the dysphagia group was statistically much greater than that in the non-dysphagia group (P=0.048). The proportion of patients with anterior open bite in the dysphagia group was higher than that in the non-dysphagia group.
Conclusion: These results suggest that the bite force and anterior open bite might influence dysphagia in MyD patients; however, this remains a speculation. It is necessary to consider masticatory disturbances in MyD patients with dysphagia.