Differences in the factors associated with tongue pressure between children with class I and Class II malocclusions.

BACKGROUND: The relationship between tongue pressure and masticatory performance during the mixed dentition period in cases of Class II malocclusion has not been clarified. The aim of this study was to determine differences in tongue pressure-related factors, including maxillofacial morphology and masticatory performance, between Class I and Class II malocclusions during the mixed dentition period. METHODS: A total of 56 children with Class I malocclusion (12 boys, 16 girls) or Class II malocclusion (16 boys, 12 girls) with mixed dentition were included in the present study. Height, body weight, hand grip strength, maximum occlusal force, maximum tongue pressure, masticatory performance, and the number of decayed, missing, and filled teeth were measured in all participants. Their lateral cephalograms were also evaluated. The means of all measurements were compared between Class I and Class II malocclusions. Pearson's correlation coefficients were used to determine associations between maximum tongue pressure and other variables for each type of malocclusion. RESULTS: The maximum tongue pressure, hand grip strength, and maximum occlusal force in the Class II malocclusion group were significantly lower than those in the Class I malocclusion group (all, p < 0.05). The maximum tongue pressure was significantly positively correlated with hand grip strength, maximum occlusal force, masticatory performance, and SNB (sella, nasion, B point) angle in the Class I group (all, p < 0.05), and with height, body weight, and labial inclination of the central incisors in the Class II group (all, p < 0.05). CONCLUSIONS: The maxillofacial morphometric factors associated with tongue pressure were clearly different between cases of Class I and Class II malocclusion with mixed dentition. Masticatory performance and tongue pressure were significantly positively correlated in cases of Class I malocclusion, but not in cases of Class II malocclusion.

The factors related to decreases in masticatory performance and masticatory function until swallowing using gummy jelly in subjects aged 20-79 years.

BACKGROUND: There is growing international interest in the prevention of decreased oral function for managing oral health in older people. OBJECTIVE: The aims of the present study were to identify factors related to decreases in masticatory performance and masticatory function until swallowing in subjects aged 20-79 years old. METHODS: A total of 152 subjects, ranging in age from 20 to 79 years, were divided into six groups according to their chronological age: 20-29, 30-39, 40-49, 50-59, 60-69 and 70-79 years. Grip strength, maximum occlusal force, maximum tongue pressure, masticatory performance and swallowing threshold were measured in all subjects. Masticatory performance and swallowing threshold were determined according to the concentration of dissolved glucose obtained from gummy jellies; decreased masticatory performance and decreased swallowing threshold were defined as glucose concentrations in the lowest 20th percentile. A multivariate binary logistic regression analysis was used to identify factors associated with decreased masticatory performance and decreased swallowing threshold. A self-administered lifestyle questionnaire was also completed. RESULTS: Logistic regression analyses revealed that factors related to decreased masticatory performance included use of more than one kind of medicine for treating chronic diseases and removable denture use, while factors related to decreased swallowing threshold included eating between meals once or more per day, poorer mental health and decreased saliva flow. CONCLUSIONS: Different factors are related to decreased masticatory performance and decreased swallowing threshold, although both of these phenomena are closely associated with general health status.

Factors associated with masticatory performance and swallowing threshold according to dental formula development.

OBJECTIVE: The aims of the present study were to the determine changes in, and factors related to, masticatory performance and swallowing threshold according to dental formula development. METHODS: A total of 120 subjects, ranging in age from 4 to 19, and 21 to 29 years, were included in the present study. Grip strength and maximum occlusal force were measured in all subjects. Masticatory performance and swallowing threshold (including the number of chewing cycles and chewing time), were determined according to the concentration of dissolved glucose obtained from gummy jellies. The 12-item General Health Questionnaire (GHQ-12) was used to assess mental health status in participants 21 to 29 years of age. RESULTS: In the primary dentition, masticatory performance and glucose concentration before swallowing were the lowest in all dentition groups. Masticatory performance was the highest in subjects 21-29 years of age. In children with mixed and permanent dentition, glucose concentration levels before swallowing were similar to those in individuals aged 21-29 years. Multiple regression analysis revealed that maximum occlusal force was significantly and positively correlated with glucose concentration before swallowing in children, and the GHQ-12 score was significantly and negatively correlated with glucose concentration before swallowing in young adults. CONCLUSIONS: Changes in swallowing threshold did not coincide with masticatory performance according to dental formula stage. Maximum occlusal force was the variable most strongly associated with swallowing threshold in children, while in young adults, better mental health status was closely associated with a higher swallowing threshold.