• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.406-411
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• 2001

The expandable implant employs an inner expansion screw in order to expand several legs of implant. Compressive stresses are produced at the bone tissue surrounding the implant, and the contact area between the implant and the bone tissue is increased, which result in increased resistance to horizontal and vertical pressure loads. The stress distribution in implant is also an important factor. Three types of implant models including an existing one have been investigated by using the Finite Element Method, and an improved design model has been suggested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1316-1319
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• 2003

The micromovements and stress distributions of cancellous bone in dental implant system play important roles in evaluating chewing function of an implant system. The micromovements and stress distributions in dental implant system generally depend on the chewing force and bone properties. Three dimensional nonlinear finite element analysis has been employed to investigate this issue quantitatively. Chewing forces and bone properties are classified into several groups and three types of implants involving one classical cylindrical type and two expandable implants are investigated in this paper.

• 구강회복응용과학지
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• 제29권1호
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• pp.101-110
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• 2013

T4K는 혼합치열기의 2급 부정교합 환자에게 사용되는 기능성, 가철성 교정장치이다. 기능성 교정장치의 경우 치열과 악골의 성장에 영향을 주는 구강안면부의 근육의 부조화를 개선시키는 역할을 한다. T4K에 포함된 lip bumper는 과도한 하순의 힘을 차단하여 주고, 하순 내측 전정을 자극하는 요소가 포함되어 있다. 부적절한 혀의 위치를 교정할 수 있는 요소는 환자들이 장치를 장착하는 동안 부가적인 혀 운동을 할 필요성을 감소시킨다. 2급 부정교합 환자의 경우 하악 열성장을 동반하는 경우가 대부분을 차지한다. 이 장치는 상악 치아를 고정원으로 하여, 하악을 전방으로 성장할 수 있도록 자극하여 부족한 하악 성장을 촉진하는 역할을 하고 있다. 이와 함께 부가적으로 Labial bow와 같은 역할을 하는 요소는 상악 치열의 개선에 도움을 준다. T4K는 기성품으로 작은 부피와 부드러운 질감으로 어린 환자들의 장착 동의율을 높이는 데 장점을 가진다. 원광대학교 치과대학 산본치과병원 소아치과에 내원한 혼합치열기의 2급 부정교합 환자에서 만족스러운 결과를 얻었기에 이를 보고하는 바이다. 요약 1. T4K를 혼합치열기의 2급 부정교합 환자에게 사용하여 안모의 개선을 얻었다. 2. 과도한 수직, 수평 피개교합이 개선되었다. 3. 하악 열성장 환자에서 T4K를 장착하여 하악 성장을 촉진하는 결과를 얻었다. 4. 구호흡 등과 같은 구강악습관의 개선을 얻었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권4호
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• pp.279-288
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• 2007

In the present study, we focused on stem cells in the dental papilla of the tooth germ. The tooth germ, sometimes called the tooth bud, is the primordial structure from which a tooth is formed. The tooth germ consists of the enamel organ, the dental papilla, and the dental follicle. The dental papilla lies below a cellular aggregation of the enamel organ. Mesenchymal cells within the dental papilla are responsible for formation of dentin and pulp of a tooth. Tooth germ disappears as a tooth is formed, but that of a third molar stays in the jawbone of a human until the age of 10 to 16, because third molars grow slowly. Impacted third molar tooth germs from young adults are sometimes extracted for orthodontic treatment. In the present study, we evaluated the osteogenic activity and mineralization of cultured human dental papilla-derived cells. Dental papillas were harvested from mandible during surgical extraction of lower impacted third molar from 3 patients aged 13-15 years. After passage 3, the dental papilla-derived cells were trypsinized and subsequently suspended in the osteogenic induction DMEM medium supplemented with 10% fetal bovine serum, 50 g/ml L-ascorbic acid 2-phosphate, 10 nM dexamethasone and 10 mM -glycerophosphate at a density of $1\;{\times}10^6\;cells/dish$ in a 100-mm culture dish. The dental papilla-derived cells were then cultured for 6 weeks and the medium was changes every 3 days during the incubation period. Dental papilla-derived cells showed positive alkaline phosphatase (ALP) staining during 42 days of culture period. The formation of ALP stain showed its maximal manifestation at day 7 of culture period, then decreased in intensity during the culture period. ALP mRNA level was largely elevated at 1 weeks and gradually decreased with culture time. Osteocalcin mRNA expression appeared at day 14 in culture, after that its expression continuously increased in a time-dependent manner up to day 28. The expression remained constant thereafter. Runx2 expression appeared at day 7 with no detection thereafter. Von Kossa-positive mineralization nodules were first present at day 14 in culture followed by an increased number of positive nodules during the entire duration of the culture period. Osteocalcin secretion was detectable in the culture medium from 1 week. The secretion of osteocalcin from dental papilla-derived cells into the medium greatly increased after 3 weeks although it showed a shallow increase by then. In conclusion, our study showed that cultured human dental papilla-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix.