| Summary: | 碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 94 === The purpose of this study was to evaluate the soft food mixing efficiency by using a newly developed standardized test food. And evaluate the relationship between the soft food mixing efficiency, jaw motion and dental occlusal morphology.
Twenty six young adults (thirteen male and thirteen female) were included in this study. All subjects had Angle’s Class I complete dentition, no dental defect or periodontal disease, no denture restoration other than single crowns and no TM joint or masticatory muscle disorders. The test food was a chewing gum block containing hydroxylapatite (HA) particles. All subjects sat in the chair without head rest, and chewed with their preferred side teeth under a constant rhythm (60Hz). Sessions of 5, 10, 15, 20, 25 and 30 chewing strokes was performed randomly. After each chewing, the HA homogeneity within the gum bolus was calculated and defined as mixing efficiency. The chewing movement of 30 chewing strokes was recorded with sironathograph (BioPAK JT3 system). Also, for the observation of occlusal contact area effects on the soft food mixing efficiency, stone model of the functional side first molar was obtained and sectioned. The occlusal cut-surface area (OCA) of preferred side was measured.
It was found that, the HA homogeneity within the chewed gum bolus was increased as chewing stroke numbers increased. The HA homogeneity stopped to increase after 25 chews.
The influence of the jaw movement recording system on chewing efficiency was found more evident in female subjects.
There was significantly wider lateral displacement in male subjects (p < 0.05). Also, the maximum velocity to the working side and fontal chewing cycle horizontal displacement were significantly larger in male subjects (p < 0.05). The jaw motion parameters, including 3 dimensional displacements (vertical, anteroposterior and left-right), 3 dimensional maximum opening and closing velocity were decreased as chewing processing, except the maximum velocity to the balancing side. Also the sagittal chewing cycle horizontal displacement was decreased as chewing processing.
There were no significant correlations between fontal chewing cycle parameters (including frontal cycle displacement, frontal cycle angle and frontal cycle width) and OCA (R2 < 0.05, p > 0.05).
Under the design of this study (using the arbitrary rhythm: 60Hz), the range of jaw motion (vertical, anteroposterior and left-right displacement) were larger, the soft food mixing efficiency were better. For soft food mixing efficiency, the chewing cycle horizontal width was much important than chewing cycle angle (eigenvector: F-C-W = 0.23, F-C-A = 0.14; S-C-W = 0.18, S-C-A = 0.10). The jaw motion difference between male and female subjects was the key factor to make differnet mixing efficiency. Compared with other parameters, the OCA had smaller effect to soft food mixing efficiency.
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