FUNDAMENTALS OF ORAL BIOMEDICINE-口腔生物医学基础 内容简介

口腔医学专业研究生（硕士、博士），也可供口腔医学及相关专业科研人员参考。

FUNDAMENTALS OF ORAL BIOMEDICINE-口腔生物医学基础 目录

chapter 1 molecular regulation of tooth development and dental stem cells zhen tian
part ⅰ　tooth development
part ⅱ　molecular regulation of tooth development
2.1 initiation of the tooth
2.2 bud-to-cap transition
2.3 condense of mesenchyme
2.4 enamel knot and tooth type determination
2.5 the homeobox code
2.6 hard tissue formation
part ⅲ dental stem cells
3.1 different populations of dental stem cells with diverse potential
3.2 tooth tissue regeneration
references
part ⅰ　tooth development
there are many things that make teeth special: froman evolutionary genetic standpoint， they contain thehardest biological substance; much of our understandingof animal evolution is based on teeth; forensicscience relies on dental records for identification.from a developmental perspective， the modelof tooth development offers a useful paradigm forstudying patterning and morphogenesis or the dete-rmination of position， size， shape and number duringorganogenesis (1).
teeth are highly mineralized and the bulk ofa tooth is composed of a mineralized tissue calledthe dentin， which is a bone-like matrix characterizedby closely packed dentinal tubules that containthe cytoplasmic extensions of odontoblasts (2).dentin is the major component of the tooth and iscompletely surrounded by enamel in the crown andby cementum in the root. it is a mineralized tissue，formed of a network of type i collagen fibrils andcarbonated apatite crystals organized in a tubularpattern. dentin surrounds the pulp， which is the softconnective tissue that occupies the central portionof the tooth. the dental pulp is rich in fibroblastlikecells， blood vessels and nerves. odontoblastscontinue to deposit dentin throughout life. theprimary dentin forms till the completion of root development，secondary dentin forms at the roof andfloor of the pulp chamber after root formation and ，reactionary dentin (tertiary dentin) is formed by theoriginal odontoblasts in response to stimuli， suchas dental decay or restorative treatment. dentin andpulp are related embryologically， histologically andfunctionally. they are usually described together as“dentin-pulp complex”.
the dentition is derived from the first branchialarch， or from two major cell types: stomodealectoderm and cranial， neural crest derived ectomesenchymecells (3). the tooth development begins asa thickening of the oral epithelium. then the epitheliumat specific sites invaginates into the underlyingmesenchyme form the dental placode. the dentalplacode then further invaginates into the surroundingdental mesenchyme to form a tooth bud. at thisstage， the mesenchyme proliferates and condensatesaround the tooth bud. after that， the epithelium ofthe tooth bud folds to form a cap-shaped structure .
the folding divides the epithelium into the innerand outer enamel epithelium. the mesenchymalcells adjacent to the inner enamel epithelium willform the dental papilla and those near the outsidewill form the dental follicle. morphogenesis fromthe bud to the cap stage involves the formation ofenamel knot， which is an important signaling centerfor tooth morphogenesis. the enamel knot is transientstructure and will disappear at the end of thecap stage， but molars will continue to form secondaryenamel knot， which determines the locationsand shapes of the molar cusps (4).
subsequently， the dental epithelium furtherfolds and extends into the mesenchyme to formbell-shaped tooth germs and then the enamel knotdisappears. at the late bell stage， cell differentiationstarts: the cells of the internal enamel epitheliumdifferentiating into ameloblasts (enamel-producingcells) while adjacent cells in the dental papilla differentiatinginto odontoblasts (dentine-producingcells). the ameloblasts and odontoblasts depositenamel and dentin back-to-back and mineralizationof the sematrices forms the two principal hard tissuesof the tooth.
after the tooth crown formed， epithelial cellsof the inner and outer enamel epithelium proliferatefrom the cervical loop of the enamel organ and forma double layer of cells known as hertwig’s epithelialroot sheath. this sheath of epithelium extendsand encloses all but the basal portion of the dentalpulp. the inner enamel epithelial cells of the sheathinitiate the differentiation of odontoblasts fromectomesenchymal cells at the periphery of the pulpand form the dentin of root. cementum formationoccurs later and cementoblasts are the cells responsiblefor cementogenesis. during the roots formation，the supporting tissues also developed. aftertooth eruption， with the formation of root apex， thedevelopment of tooth is completed (5，6).

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