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Biomedical subjects

S Y Chuang

Publications and source records attributed to S Y Chuang.

7 recordsLinked to original sources
PubMed2005

Condylar resorption during active orthodontic treatment and subsequent therapy: report of a special case dealing with iatrogenic TMD possibly related to orthodontic treatment.

A 28-year-old female underwent orthodontic treatment for approximately 22 months. During the later stages of this treatment, the patient reported right shoulder and neck-muscle pain. In addition, temporomandibular joint disorder (TMD) with a 'clicking' sound during mastication commenced 5 months prior to treatment completion. Specific medication to deal with these symptoms was suggested by medical specialists, as were some stress-relief methods, although the pain still progressed, and subsequent clinical and radiographical examinations were undertaken by another orthodontist. Right mandibular condylar resorption was observed from both the panorex and temporomandibular joint (TMJ) radiographs. No clinical signs of rheumatic disease were observed, although bruxism was noted. Following the termination of the orthodontic treatment by the second practitioner, the patient was treated with splint therapy 1 month subsequent to which, the previous symptoms of pain in the shoulder and neck, and the clicking sound during mastication had subsided. During the 14-month period of splint therapy and follow-up, new bone growth in the right condyle was observed from radiographs.

Adult↗
PubMed2002

Experimental verification of the effects of optical wavelength on the amplitude of laser generated ultrasound in polymer-matrix composites.

Laser ultrasound is now integrated into the manufacturing process of some of the most modern aircraft for the inspection of composite parts. Unfortunately, for some material and process combinations, laser-ultrasound suffers from a lack of sensitivity. In laser-ultrasound generation, optical penetration depth plays a very important role. It was shown that changing the generation wavelength from the 10.6 microm of the CO2 laser to the 3-4 microm range can significantly improve generation efficiency. In this paper, ultrasonic displacements are compared to measurements of optical penetration depth in different polymer-matrix composites. Ultrasonic waves were generated using an optical parametric oscillator operating in the 3.0-3.5 microm band and optical penetration depth spectra were evaluated using quantitative photoacoustic spectroscopy. The relative amplitudes of the generated ultrasonic waves track closely the optical penetration depth spectra. These results experimentally demonstrate the importance of optical penetration in the laser-ultrasound generation process.

Journal Article↗
PubMed2000

Craniofacial growth changes of Mongolian children with normal occlusion from 8 to 12 years.

The purpose of this study is to quantify the changes of craniofacial skeleton in Mongolian children born in Taiwan. They had normal occlusion and pleasing profiles, received no previous orthodontic treatment, and were aged 8 to 12 years. The subjects included 24 boys and 24 girls from whom lateral cephalograms were taken for the study. After measurements and statistical analysis, the findings in this investigation indicated the following: 1. Although the growth of the mandible showed forward and upward rotation, the growth pattern of craniofacial portion from ages 8 to 12 was stable with no significant difference in angular measurements. Nevertheless, there were significant differences in linear measurements. The linear dimensions exhibited a gradual increase with age for both boys and girls. This fact should be considered in the diagnosis and treatment plan for young patients under 12 years old with anteroposterior discrepancies. 2. There was a considerable degree of sexual dimorphism with boys showing greater angles in the maxilla-mandibular relationship and greater late skeletal and dental changes. Most of the changes in various parameters occurred earlier in girls, and in boys these changes were distributed more evenly over the entire period of study.

Child↗
PubMed1998

Osteoid osteoma in the talar neck: a report of two cases.

This article describes two cases of juxta-articular osteoid osteoma of talar neck. Both patients were initially treated as having ankle sprains or arthritis before diagnosis of osteoid osteoma. A high index of suspicion and appropriate imaging studies are important to make an early diagnosis of this disorder. Once diagnosis is confirmed, en bloc resection and autogenous bone graft can cure the disorder.

Adolescent↗
PubMed1995

[The relationship between masticatory function and craniofacial morphology].

In 1960, the functional matrix hypothesis was first articulated by Moss. Although many investigators agreed that there were genetic influences on craniofacial growth, the functional demands of matrices are more significant in determining craniofacial morphology during growth. Therefore, during postnatal growth, an intimate functional relationship exits between the jaw muscles and the bones to which they are attached. The most recent findings suggest that the morphological changes can be observed not only in areas adjacent to muscle insertion but also in growth sites affecting the rotational growth pattern of the cranium. If this is true, the reduced functional demands on the masticatory muscles may cause some changes of craniofacial growth. To test this hypothesis, a longitudinal study by means of cephalometric analysis to observe the changed masticatory function induced by a diet of physically soft food on the craniofacial morphology in the growing rabbits was conducted. One group of rabbits was fed with a soft diet, while another group received a standard laboratory diet and served as the control group. These animals had been weaned at the start of the experiment (1 month of age), and the experimental period last for 6 months. During that time, all rabbits were weighed every month, and lateral cephalograms were taken with the skull fixed in a specially constructed cephalostat. The procedure of taking a cephalogram entails the sacrifice of the subject. Thus five rabbits in each group were sacrificed each experimental period. The radiographic images were copied on photographic paper, magnified by two and the cephalometric analyses were performed. The results are as follows: 1. There were no statistical differences between groups in any of the test periods for body weights. 2. The results of cephalometric analysis showed that no difference in overall skull shape could be found between the two groups, but a more anterior superior growth rotation of the upper jaw occurred in the rabbits fed with soft diet compared to the rabbits fed with a standard laboratory diet. Thus, the skull became more erect position in the soft diet group. 3. In the soft diet group, the angular process of the mandible was less convex. That was a clockwise growth pattern. In addition, there was a thin and flat shape of mandibular body in compared to control group.

Animals↗
PubMed1981

Detection of a phase transition in red cell membranes using positronium as a probe.

Positron lifetimes in human red cell ghost membranes have been measured as a function of temperature from 3 degrees C to 25 degrees C. A marked sudden change in the ortho-positronium annihilation rate was found at 16-18 degrees C during the heating cycle and at 18-20 degrees C in the cooling cycle. Such sudden change of microenvironment in the membranes sensed by ortho-positronium is attributed to the sudden change of water diffusion rate through the membranes which is a consequence of the sudden change in free volume, or fluidities in the lipid layers.

Elementary Particles↗