• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.311-321
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• 1995

This study was undertaken to investigate the distribution of the chewing side preference and variations in the maximum bite force and facial morphology according to chewing side preference since unilateral chewing may cause morphologic and functional anomalies. 50 dental students who had no signs or symptoms of masticatory system and Angle's Class I relationship in posterior segments were selected, and divided into two groups, that is, 25 in bilateral chewing group(19 male and 6 female) and 25 in unilateral chewing group(10 male and 15 female). Maximum bite force was estimated ana posteroanterior cephalogram were measured ana statistically analyzed. The results were as follows : 1. Their were more students with bilateral chewing side preference($68\%$) and unilateral chewing side group consisted of right side preference($68\%$) and left side preference($32\%$). 2. There was no significant difference in the strength of max. bite force between the right and left side in bilateral chewing group. The bite force of the chewing side nab greater in the unilateral chewing group but less in the non-chewing side compared to those of bilateral chewing group with Bo significant difference. Max. bite force of chewing side was greater than that of non-chewing side in the unilateral chewing group(Female p<0.05). Max. bite force of males was about twice in that of females in both groups(p<0.05). Max. bite force of chewing side of the unilateral chewing group was similar to that of the bilateral chewing group, but that of non-chewing side was less than that of the bilateral chewing group. 3. In comparison of the facial morphology, there was no statistically significant difference in the size between the right and left side of the bilateral chewing group and between chewing and non-chewing side of the unilateral chewing group.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.513-518
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• 2007

Loss of multiple teeth by multiple dental caries, traumatic influence or hereditable disease can cause many problem in children. Using removable appliance can be used for treatment of this problem. But conventional removable appliance has limits of retention by wire-clasp, non esthetic appearance, difficulty in pronunciation by its volume. Flexible denture using $Valplast^{(R)}$ system could be a excellent partial denture for restorarion in child because of various advantage such as retention from soft tissue, natural esthetic aspect, biocompatibility, durability to compare with conventional acrylic appliance. The present case report describe properties and consideration of flexible denture using Valplast $system^{(R)}$ in comparison with conventional acrylic appliance and report successful restoration of child using Valplast $system^{(R)}$.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.45-55
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• 2005

As people prefer to use right or left hand, some have preferred chewing side while others do not. Totally, 82 volunteers composed of students and staffs from Dental Hospital College of Dentistry Yonsei University participated in this study for the investigation of influence of preferred chewing habit, that has lasted for more than a year, on electromyographic(EMG) activity of masticatory muscles and bite force. Among the 82 volunteers, 46 had preferred chewing habit while the other 36 did not. Prior to the investigation, those with factors that could affect the study, such as, general disease, irregular dentition and malocclusion, were screened and excluded by questionnaire and clinical examination. The results were as follows: 1. There was no significant difference in EMG activities between chewing side and non-chewing side of preferred chewing subjects at rest as well as maximal voluntary contraction(MCV)(p>0.05). 2. Asymmetrical coefficient of temporal and masseter muscle EMG activities between preferred chewing subjects and non-preferred chewing subjects at rest was not significantly different(p>0.05). 3. Asymmetrical coefficient of masseter EMG activity was significantly higher(p<0.05) than that of non-preferred chewing subjects at MCV, whereas that of anterior temporal muscle showed no difference(p<0.05). 4. In preferred chewing subjects, there was no significant difference in average bite force and occlusal contact area between chewing side and non-chewing side(p>0.05). 5. There was no significant difference in Asymmetrical coefficients of average bite force and occlusal contact area between preferred chewing subjects and non-preferred chewing subjects (p>0.05). Consequently, preferred chewing habit can be considered as physiological asymmetry with normal function rather than to have influence on EMG muscle activity of masticatory muscles, average bite force and occlusal contact area. Objective standardization to differentiate preferred chewing subjects and non-preferred chewing subjects should be established in the further study.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.04a
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• pp.409-413
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• 2000

본 논문은 가상현실의 한 분야인 VRML 저작도구의 설계와 구현에 고나하여 기술하였다. 가장 효과적인 장면생성과 Graphic Library (OpengL)와 VRML Noderks의 매칭 구현을 통하여 Objects 의 Rendering 수준을 한 차원 높이고, COM 기반의 Parser 사용으로 저작도구 구현에 효율성과 재사용성을 극대화하며, 3차원 모델링을 모다 손쉽게 저작할수 있는 저작도구를 구현하였다. 3차원 모델링 기술의 기반 구조가 취약한 국내에서 이 분야 기술력의 축적과 함께 3차원 모델링 기술을 이용한 응용 제품 개발의 저변확대와 다양한 유형의 쇼핑몰 구현 기반 기술 확보등의 효과를 거둘 수 있다.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.47-59
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• 2016

Purpose: The aim of this study was to investigate the changes in occlusal force after loss of the lower first molar depending on the inclination and extrusion of the adjacent and opposing teeth by using a strain gauge. Materials and Methods: Anatomic teeth were used to reconstruct the normal dental arch with loss of the lower right first molar. A uniformly thick layer of silicone was applied to the root to mimic the periodontal ligament. Four stages of dies with varying degrees of inclination and extrusion of the adjacent and opposing teeth were constructed and attached to master model interchangeably by using a CAD/CAM fabricated customized die system. The strain gauges were attached to teeth and a universal testing machine was used to determine the changes in occlusal force. An independent t-test and one-way ANOVA were performed (${\alpha}=.05$). Results: While simulating chewing food, the upper first, second premolar and lower second molar showed greater occlusal force than before extraction. When the change of adjacent teeth's occlusal force with their progressive movement after molar loss was evaluated, the difference among four die models was significant and was in the decreasing aspect (P < 0.05). Conclusion: When the lower first molar was lost and the adjacent teeth did not move yet, the occlusal force in adjacent teeth was higher than that when the lower first molar still existed. In addition, the occlusal force in the upper premolars and lower second molar decreased significantly with the progressive movement of adjacent teeth.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.1-7
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• 2016

Mastication is the process to help digestion by chewing or grinding food. Masticatory system consists of maxilla, mandible, temporomandibular joints, ligaments, dentitions, and musculatures. Assessing the bite force can be one of the methods to estimate the masticatory system. Bite force is influenced by facial morphology, age, sex, periodontal status, temporomandibular joint disorder and dental condition, and so forth. In general, higher maximum bite force is seen in those who have a square-shaped face and in male rather than female. In addition, bite force tends to be increased by age 20, maintained constantly until age 40 - 50, and then decreased. Periodontal disease is known as a causative factor for decreased bite force while temporomandibular disorder (TMD) remains controversial as to whether it affects the force. The status of teeth is considered as an important factor to determine the maximum bite force.

• The Journal of the Korean dental association
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• v.20 no.12 s.163
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• pp.1005-1010
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• 1982

노화란 무엇이며 왜 일어나는 것이며, 노화되면 어떻게 되는가에 대하여 많은 연구가 되어 왔지만 아직도 모르는 부분이 많은 것 같다. 우리 몸의 중요기관의 기능은 30세부터 점차 기능이 떨어지면서 늙으면 청년기의 거의 반으로 떨어진다. 늙으면 심장, 폐의 기능뿐만 아니라 활동력도 젊은 때보다 급격히 떨어지며 저작력도 마찬가지로 떨어진다. 본란에서는 주로 청년기이후에 나타나는 조직의 변화를 설명코저 하며, 노화에 따른 구강조직의 변화를 이해함으로서 구강건강을 유지시키고, 노인환자의 성공적인 치료에 도움이 되리라고 생각한다.

• The Journal of Korean society of community based occupational therapy
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• v.10 no.1
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• pp.31-38
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• 2020

Objective : The purpose of this study is to investigate the effects of bilateral chewing exercise applied for 6 weeks on occlusion force and masseter muscle thickness in the elderly living in the community. Methods : This study recruited 25 community residents. All participants performed bilateral chewing exercise using equipment developed for the purpose of oral chewing exercise. The chewing exercise was divided into isometric and isotonic type and applied for about 20 minutes a day, five times a week for six weeks. For the evaluation, the masseter muscle thickness and the maximum occlusion force were measured three times at three week intervals using a portable ultrasound instrument and an occlusion force gauge. Results : As a result of the change in masseter muscle thickness, baseline, 3 weeks later, and 6 weeks later referred to 7.51±0.43, 7.63±0.44, and 7.83±0.46, respectively (F=3.819, p<.05). The post hoc test resulted in a significance between baseline and 6 weeks later (p=0.023). Similarly, as a result of the change in occlusion force, baseline, 3 weeks later, and 6 weeks later referred to 265±9.22, 268±9.57, and 271.59±10.16, respectively (F=3.031, p<.05). The post hoc test resulted in a significance between baseline and 6 weeks later (p=0.048). Conclusion : This study confirmed that bilateral chewing exercise was effective for increasing masseter muscle thickness and occlusion force in the elderly. Therefore, bilateral chewing exercise can be applied as a therapeutic exercise method for improving oral function.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.1025-1026
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• 2010

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.269-276
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• 2012

Many researches have been published about the numerous factors related to the chewing ability of implant prosthesis. Most respective studies have concluded that the chewing ability of implant prosthesis is mostly fine compared to other type of prosthesis. However, some patients are not satisfied with their chewing ability of implant prosthesis. Therefore the neurologic factor, one of the factors related to dissatisfaction of chewing ability was reviewed in this study to understand the mechanism of action of mastication. Data was searched using the keywords; 'implant chewing ability, masticatory ability' in Pubmed database and reviewed. Definitions of chewing ability, factors of chewing ability are reviewed and the neurologic factor, one of the factors influencing on chewing ability, is reviewed. Mechanoreceptor of Periodontal ligament(PDL) is providing the mastication information to brainstem. Due to the absence of mechanoreceptions of PDL in implant, masticatory ability is decreased especially when chewing hard food. Masticatory muscles and mechanoreceptor in TMD may compensate the lack of mechanoreceptor of PDL in implants. Furthermore sensitivity of nerve fiber around peri-implant tissues may support the mechanoreception and sensory reaction in the implant mastication. However, further studies should be conducted to prove the relationships between neurologic factors and mastication.