• 대한치과교정학회지
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• 제33권4호
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• pp.279-291
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• 2003

낮은 강도의 전류는 골세포의 활성화 대사를 증가시키는 것으로 알려져 왔다. 이 연구는 초소형 전기 장치에 의한 전기 자극이 교정적 치아 이동에 미치는 영향을 규명하기 위하여, 체중 3kg내외의 고양이 6마리를 대상으로 가철성 교정장치와 NiTi coil spring(75gm)을 사용하여 상악 견치를 이동시켰다. 실험군측 견치에는 교정력과 간헐적인 $20{\mu}A$의 전기 자극을 가하였고, 대조군측에는 같은 크기의 교정력만을 가한 후 4주 동안의 치아 이동량을 측정하여 비교하였으며, 치아를 중심으로 조직을 절취하여 탈회하고 조직 처리 후 광학 현미경으로 치주조직의 변화를 비교하여 다음과 같은 결론을 얻었다. 1. 28일간의 실험 기간 동안 실험측의 치아 이동량은 대조군에 비하여 현저히 증가하여, 4주후에 실험측의 치아는 대조군에 비하여 37% 증가된 이동량을 기록하였다. 2. 전기 자극을 받은 치아의 치근 견인측에서 대조군에 비하여 조직학적으로 증가된 골형성 양상이 관찰되었다. 3. 28일간의 전기 자극과 교정력으로 실험측 치아의 압박측에서 대조군에 비하여 증가된 골 흡수 양상이 관찰되었다. 4. 실험군 견치 치근 주위 조직에서는 전반적으로 더 많은 수의 조골 및 파골 세포들과 모세 혈관, 골양 조직들이 관찰됨으로써 증가된 조직 세포 활성을 반영하였다. 5. 1일 5시간 동안의 간헐적 전류 자극은 치아 이동량을 증가시키고 조직 개조를 활성화시키는 효과가 있었다. 이상의 결과는 외부에서 가한 낮은 강도의 간헐적 전기 자극으로 교정적 치아 이동량이 많아지고 치주 조직의 개조 활성이 증가됨을 보이므로 초소형 전기 장치에 의한 자극은 치아 이동과 주위 조직 개조를 촉진시킬 가능성이 있을 것으로 평가되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.511-519
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• 2006

Autogenous bone grafts have been considered the gold standard for maxillofacial bony defects. However, this procedure could entail a complicated surgical procedure as well as potential donor site morbidity. Possibly the best solution for bone-defect regeneration is a tissue engineering approach, i.e. the use of a combination of a suitable scaffold with osteogenic cells. A major source of osteogenic cells is the bone marrow. Bone marrow-derived mesenchymal stem cells are multipotent and have the ability to differentiate into osteoblastic, chondrocytic, and adipocytic lineage cells. However, the isolation of cells from bone marrow has someproblems when used in clinical setting. Bone marrow aspiration is sometimes potentially more invasive and painful procedure and carries of a risk of morbidity and infection. A minimally invasive, easily accessible alternative would be cells derived from periosteum. The periosteum also contains multipotent cells that have the potential to differentiate into osteoblasts and chondrocytes. In the present study, we evaluated the osteogenic activity and mineralization of cultured human periosteal-derived cells. Periosteal explants were harvested from mandibule during surgical extraction of lower impacted third molar. The periosteal cells were cultured in the osteogenic inductive medium consisting of DMEM supplemented with 10% fetal calf serum, 50g/ml L-ascorbic acid 2-phosphate, 10 nmol dexamethasone and 10 mM -glycerophosphate for 42 days. Periosteal-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 14 of culture period, then decreased in intensity during the culture period. ALP mRNA expression increased up to day 14 with a decrease thereafter. Osteocalcin mRNA expression appeared at day 7 in culture, after that its expression continuously increased in a time-dependent manner up to the entire duration of culture. 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. In conclusion, our study showed that cultured human periosteal-derived cells differentiated into active osteoblastic cells that were involved in synthesis of bone matrix and the subsequent mineralization of the matrix. As the periosteal-derived cells, easily harvested from intraoral procedure such as surgical extraction of impacted third molar, has the excellent potential of osteogenic capacity, tissue-engineered bone using periosteal-derived cells could be the best choice in reconstruction of maxillofacial bony defects.

• 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.

• 한국식품영양과학회지
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• 제25권6호
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• pp.993-1005
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• 1996

본 연구는 폐경 후 여성에게 식이 칼슘염 형태, 에스트로겐 및 에스트로겐/칼슘 혼합요법이 골대사의 생화학적 변화에 미치는 영향을 알아보고자 난소절제쥐를 이용한 총 9군으로 분류하여 6주간 사육한 후 그 효과를 살펴보았다. 식이 섭취량, 식이 효율 및 체중 증가량은 난소절제로 현저히 증가하였으나 난소절제 후 estrogen 투여군 모두에서 식이 섭취량이 크게 감소되었다. 골흡수의 지표로 사용되는 소변으로 배설되는 hydroxyproline 함량은 난소절제로 현저히 증가하였으나, 난소절제 후 estrogen 투여군 모두에서 감소하였는데, 특히 estrogen/칼슘 혼합 투여군에서 가장 많은 감소를 나타내었다. 혈장 부갑상선 호르몬 함량은난소절제로 다소 증가하나, 난소절제 후 estrogen 및 estrogen/칼슘 혼합군에서 혈장 중 부갑상선 호르몬 수준이 32%나 감소되었다. 그러나 estrogen 점진적 감소군에서는 현저한 감소를 나타내지 않았다. 골생성 및 조골세포형성의 지표인 osteocalcin 함량과 AP 활성은 난소절제로 현저히 증가하였으나, 난소절제 후 estrogen 투여군 모두에서 감소하였다. 이상의 성적으로 보아 estrogen 및 estrogen/칼슘 혼흔합요법은 골교체율을 감소시켜 골손실을 방지하는데 효과적인 방안임을 확인할 수 있었으며, 한편 estrogen 점진적 감소요법은 골손실 감소에 크게 기여하지 못하나, estrogen점진적 감소와 고칼슘 투여군, estrogen 점진적 감소와 칼슘 점진적 증가군에서는 골손실을 상당량 방지할 수 있음을 알 수 있었다. 칼슘염 종류에 따른 골손실에 미치는 생화학적 요인들의 변화는 크게 나타나지 않았다.