Severe unilateral pharyngeal weakness causes retention of the food bolus after swallowing in post-stroke individuals with dysphagia. Head rotation to the weak side can divert the bolus to the strong side.The effectiveness of head rotation on swallowing a liquid bolus has been reported. However, its effectiveness on pre-swallow bolus transport during eating food is still unknown. We examined the effects of head rotation on the passage side of bolus flow through the pharynx during eating two-phase food (containing solid food and liquid). Fifteen healthy subjects were imaged with video-endoscopy while eating a mixture of liquid and solid food. Head rotation angles were classified as no rotation, 30 degree and maximum rotations for both right and left sides. The side of pre-swallow bolus flow through the oropharynx during chewing was evaluated on digitized endoscopic images.
On the valleculae, the food tended to pass through the rotated side. In contrast, at the hypopharynx, the food tended to flow through the opposite side. Just before swallow initiation, in the valleculae, the food was mainly at the middle and rotated sides, but in contrast, in the hypopharynx, the food was more at the opposite side to head rotation. The percentage of subjects with food passage through the rotated side was not significantly different between with 30 degrees and maximum rotations.
We found that, with head rotation, the food flowed into the rotated side of the oropharynx and changed its direction to the opposite side at the level of the base of the epiglottis. This would be mainly caused by the contact between the epiglottis and the lateral pharyngeal wall at the rotated side. The head rotation would influence on pre-swallow food transport in the pharynx during eating.

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Nondestructive testing (NDT) is a wide group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing damage. However, no application of NDT to dental materials has been reported until now.
Oral dysfunction caused by denture problems not only inhibits the diet, but also reduces the QOL of the elderly. Quality control is also an important aspect of denture fabrication from the standpoint of providing dentures of acceptable clinical value and assuring the safety of products.
The purpose of this study was to present the first inner examination of resin artificial teeth using a new advanced-type OCT (Optical coherence tomography) scanner we have developed, and to discuss the application of our new OCT system for non-destructive inspection of resin artificial teeth.
Four commercial brands of acrylic resin artificial teeth were used for inspection by OCT, which provided clear images of all the artificial teeth examined. Internal structures, not visually detectable, inspection, can be clearly observed using this OCT system.
It is concluded that OCT can detect nonvisible internal structures of artificial teeth, a finding not reported to date. OCT may, therefore, be an appropriate method for detecting interior defects of artificial teeth nondestructively.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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