• The korean journal of orthodontics
• /
• v.28 no.4 s.69
• /
• pp.547-561
• /
• 1998

Obstructive sleep apnea (OSA) is a disorder characterized by repetitive episode of upper airway collapse during sleep. Recent studies showed that not only the anatomic factors but the physiologic factors of the upper airway also have effcts on the occurrence of apnea and that the genioglossus muscle also plays an important role in the maintenance of the upper airway. A variety of therapies were performed to treat OSA, and among them the use of mandibular repositioning appliances showed reasonable results. But there is still a lack of research on the structural and physiological mechanism upon the use of mandibular repositioning appliances. The author selected 26(male 17, female 9) OSA patients that came to the Yonsei University Dental Hospital, Department of Orthodontics, and 20 normal adults (male 10, female 10) and took cephalometric radiographs of them in a supine position before and after the placement of the mandibular repositioning appliance to see the structural changes of the upper airway and compare the therapeutic effects between the two groups. We also studied the waking genioglossus muscle activity in OSA patients and investigated the difference in the electromyogram of the genioglosssus muscle upon the change in body posture and the use of mandibular repositioning appliance. Following results were obtained. 1. Among the cephalometric measurements of the upper airway structure, the length of the soft palate, maximum thickness of the soft Palate and SPAS, MAS, VAL, H-H1, MP-H showed statistically significant differences between the normal and OSA groups, but the IAS and EAS showed no statistically significant differences between the two groups. 2. In both the normal and OSA groups, as the epiglottis moved forward on wearing the mandibular repositioning appliance, the epiglottis level of the upper airway increased and the maximum thickness of the soft palate changed and the hyoid bone also moved forward, but the IAS in both groups showed various results and the effect of the mandibular repositioning appliance on the structure of the upper airway was different in the two groups. 3. Upon changing the position, the electromyogram of the genioglossus muscle showed a increasing tendency but there was no statistically significant differences, and when the mandibular repositioning appliance were worn there was a statistically significant increase in the electromyogram of the genioglossus muscle in both the upright and supine positions. The mandibular repositioning appliances not only have an effect on the anatomical structure of the upper airway but also on the physiology of the upper airway. There are different responses to the use of mandibular repositioning appliance between the normal and OSA groups therefore it could be considered to have the different physiology of the upper airway between the two groups.

• Journal of Oral Medicine and Pain
• /
• v.10 no.1
• /
• pp.113-124
• /
• 1985

In order to observe the effect of mandibular orthopedic repositioning appliance (MORA) on body strength, the author measured back muscle strength with Digital Back Muscle DYNAMOMETER (TAKEI KIKI KOGYO Co., Tokyo, Japan) before MORA, 15 days after and 30 days after MORA in 12 men and then analysed them statistically. The subjects were weight-lifting athletes of Seoul Athletic High School without dysfunction of masticatory system. MORA was fabricated at 1.0-1.5rnm isotonically closed position (Myocentric Occlusion Position) from mandibular rest position (Myocentric Rest Position) using Myo-monitor (MyoTronics Research Inc., Seattle, Washington, USA) and-SVT C-II (Tokyo Shizaisha Inc., Tokyo, Japan). The results were as follows : 1. The mean of back muscle strength before MORA was 150 kg, that of 15 days after MORA was 165 kg (4.43% increase than before), and that of 30 days was 175 kg (10.76% increase than before). 2. There was a significant difference among back muscle strength before MORA, 15 days after and 30 days after MORA (P<0.01: repeated measures one-way ANOVA). 3. According to the result of determining mandibular position for MORA fabrication, mandibular rest position after relaxation with Myo-monitor was 3.2mm lower, 1.0mm posterior, and 0.5 mm left from centric occlusion. And the mean of the amount of lateral deviation was 0.7 mm.

• The korean journal of orthodontics
• /
• v.23 no.4 s.43
• /
• pp.447-454
• /
• 1993

Patient with skeletal class II relationship was treated with L-ARS. L-ARS is fixed functional appliance that could be effective in children and adolescent patient who don't wear activator. The following results were obtained ; 1) Growth of Mandible was stimulated and overjet was decreased, therefore coupling of anterior teeth was established with L-ARS which is fixed functional appliance. 2) These changes were accomplished with Mandibular skeletal growth with no effect on the Maxilla. 3) L-ARS was especially effective on patient who deny to wear the removable functional appliance.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.4
• /
• pp.675-681
• /
• 2005

The Horseshoe appliance was introduced by Dr. Schwarz, and it is used to correct sagittal relationships by elastic force in class III malocclusion. It minimizes the increment of lower anterior facial height and allows the mandible to be repositioned harmoniously with the soft tissue and muscle matrix of the jaw It has the advantages of better patient cooperation, easier construction, and more effective modification. In the patients who were treated with Horseshoe appliance, forward growth of maxilla and counterclockwise rotation of occlusal plane with labioversion of maxillary incisors and linguoversion of mandibular incisors were obtained. Minimum downward and backward rotation of mandible was accepted, so increasing of lower anterior facial height was minimized.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.1
• /
• pp.119-125
• /
• 2005

In the primary dentitions, the majority of dental injuries involve the anterior teeth, especially the maxillary primary central incisors. When injuries affecting primary and permanent teeth are compared, it appears that trauma to the primary dentition is usually confined to the supporting structures, i.e. luxation and exarticulation, while the largest proportion of injuries affecting the permanent dentition is represented by crown fractures. But, cases reporting trauma affecting primary molars are unusual in the literature and several reports describe fractures of posterior teeth. The main goal of this report is to describe the repositioning treatment using removable appliances to an uncommon case of lingual displacement of primary molar that happened to a 4 year 5 month-old female child.

• Journal of Oral Medicine and Pain
• /
• v.24 no.1
• /
• pp.69-80
• /
• 1999

OBJECTIVES: This study was designed to measure the minimal cross-sectional areas and volumes of the pharynx in snoring patients and normal subjects and to see if there is an increase in the minimal cross-sectional areas and volumes of the pharynx with advancement of the mandible. METHODS: The pharyngeal computed tomography and 3-dimensional reconstruction were used to measure the cross-sectional areas and volumes of the nasopharynx, oropharynx, and hypopharynx with the jaw in normal position and in protrusive position in 7 patients with snoring and 7 control subjects while they were awake. RESULTS: The oropharynx was revealed to have the most narrow site in the pharynx and there was a tendency for the snorers to have a smaller nasopharyngeal and oropharyngeal cross-sectional area than normal subjects but not statistically significant. There were no significant differences in the volumes of the nasopharynx and oropharynx between the two groups. With advancement of the jaw the minimal cross-sectional area of oropharynx was significantly increased, and the volume was also increased but not significantly. The minimal cross-sectional areas and volumes of nasopharynx as well as hypopharynx were not significantly influenced by the advancement of the mandible. CONCLUSIONS: There was a tendency for snorers to have a smaller oropharynx than normal subjects and the oropharyngeal lumen was increased with the advancement of the mandible in both snorers and normal subjects.