ABSTRACT
The aims of the present study were to evaluate whether there are significant differences in masticatory performance by gender and dental stage. We also determined the factors directly associated with the masticatory performance in children, and those directly associated with masticatory performance in young adults. The study included 180 subjects, ranging in age from 6 to 12 years or 20 to 33 years. The subjects were divided into three groups according to the Hellman developmental stage (III A, III B, or VA); the groups were the subdivided according to gender. The body mass index (BMI), maximum tongue pressure, and sum of decayed, missing, and filled teeth (DMFT) were determined in all subjects. To investigate masticatory performance, the total number and maximum projected area of chewed particles of the jelly materials were measured. Masticatory performance had the highest values at Stage VA in both males and females. Regarding the maximum tongue pressure in females, Stage III B had the highest value of all stages. Multiple regression analysis showed that masticatory performance was associated with DMFT index, maximum tongue pressure, and BMI in children. Among young adults, masticatory performance was associated with DMFT index and maximum tongue pressure. Better masticatory performance is directly associated with better dental status, a higher BMI, and tongue pressure in schoolchildren. Additionally, masticatory performance was well-correlated with tongue pressure in young adults, although maximum tongue pressure reached its peak before Stage VA in females. We suggest that females need training with respect to tongue pressure, by the mixed dentition stage.
ABSTRACT
OBJECTIVES: We examined the effects of a low-calcium diet and altered diet hardness on bone architecture and metabolism in the maxilla and mandible. MATERIALS AND METHODS: Male rats (n=48, 3 weeks old) were divided into six groups. In total, 24 rats were given a normal-calcium diet and the others were given a low-calcium diet. Each group was then divided into three subgroups, which were fed a 'hardÌ diet for 8 weeks, a 'softÌ die for 8 weeks, or switched from the soft diet after 4 weeks to the hard diet for 4 weeks. The bone architecture was analyzed using cephalometry and micro-computed tomography, in addition, the bone metabolism was analyzed using serum bone markers and bone histomorphometry in the maxilla and mandible. Moreover, the bone formation patterns were evaluated using histopathologically in the midpalatal suture. RESULTS: The low-calcium diet affected bone architecture by increasing bone turnover and the soft diet affected bone architecture mainly by increasing bone resorption. The soft diet changed the chondrocyte cell layers into fibrous connective tissues in the midpalatal suture. At 4 weeks after the return to a hard diet from a soft diet, recovery of the deterioration in bone architectures was seen in the maxilla and mandible. CONCLUSIONS: We demonstrated that mastication with a hard diet is effective for recovering the collapsed equilibrium of jaw bone turnover and the deteriorating jaw bone architectures due to the poor masticatory function during the growing period.
