口腔生物学精品教学（中山大学）2.口腔骨组织生物学.docVIP

Molecular and cellular biology of alveolar bone Tang zhi-ying Guanghua school of stomatology Sun Yat-sen University Anatomic characteristics of the jawbones Jawbones are functionally subdivided into alveolar bone（牙槽骨and basal bone The development of alveolar bone is dependent on root formation The external surfaces (cortical plates，皮质骨) of the jawbones are constructed of compact（紧凑的lamellar bone（层状骨） Typical haversian systems（哈弗系统are present in the cortical plates In contrast, the tooth-bearing surfaces of the jawbones are made up of bundle bone（束状骨）(also called woven bone，编织骨) . Thus the internal wall of the alveolus is constructed of coarser and less mature bone than the lamellar bone deposited in the cortical plates The internal alveolar wall is also called the cribriform plate(筛状板) because of the many openings for blood vessels and nerves that communicate between the marrow spaces and the PDL（牙周膜 On radiographs, the cribriform plate is observed as a dense border or lamina dura (硬骨板) The inner compartment of the maxilla（上颌and the mandible（下颌,the medullary bone (髓质骨) or spongiosa (松质骨), is made up of trabecular bone (骨小梁) and marrow Interdental（牙之间的and interradicular（根尖的sites of alveolar bone contain spongy bone（松质骨with trabeculae（骨小梁arranged along lines of functional pressure generated by mastication（咀嚼 The cellular basic of bone remodeling Turnover and remodeling of alveolar bone Alveolar bone turns over more rapidly than do other parts of the skeleton The highest level of resorption（再吸收）and formation occurs in the cribriform plate（筛状板, the layer of bundle bone（束状骨adjacent to the PDL. Part of the turnover is related to normal remodelling to accommodated the mesial and occlusal shifting of teeth over time These shifts arise in part from unopposed（不受控制的tractional（牵引forces produced in the connective tissue of the periodontium and in part from mastication Mesial drift (3-4mm) Occlusal drift (mastication) Type and Functions of Osteogenic Cells Preosteoblasts（前成