牙形成

RESULTS: Before remineralization, through SEM, short blunt eeptoma was found on the surface of lesions of samples in Chinese nutgall group and Ag（ NH3 ）2F group; while in NaF group, globular ecptoma was seen scattering on the surface of the lesions, together with laeune; in deionized group, there was Sharpey＇s fiber.

结果：再矿化前，扫描电镜观察五倍子与氟化氨银处理后牙骨质龋表面形成不规则短钝状突起；氟化钠液组形成大小不一的散在大球状突起，可见一些腔隙存在；去离子水组大量分布夏伯氏纤维。

The biometallogenesis system of Jinya gold deposits consists of the following procedure: pre-concentration of gold and metallogenic matter in living organisms in Luodian-Danchi rift depositional basin; solution, absorption and concentration of metallogenic matter in organic matter and organic thermal fluid generated from organisms during lithogenesis; migration of gold and metallogenic matter in organic fluid from basin to Lingyun underwater carbonate platform and concentration at its boundary convex (palaeo-blind-mountain) during basin compaction ; metallization due to depth thermal fluid making organic fluid thermal degradation and forming new fluid which riches in gold and sulfur, and the fluid migrating upward and depositing in upside ore-controlling structures because of absorptions by organic carbon and atc.

通过研究金牙金矿作用的生物成矿系统内容为：在早、中三叠世罗甸—丹池裂谷盆地接受沉积时，生物对金等成矿物质就存在预富集作用；在成岩过程中，生物转化为有机质及有机热流体，对生物及沉积物中的金等成矿物质存在溶解、萃取、富集作用；在盆地压实成岩作用中，盆地中有机热流体向凌云水下碳酸盐台地运移，并在台地边缘外凸部位集中，此过程流体携带大量成矿物质，对金等成矿物质存在迁移集中作用；深部热流上侵使有机流体发生降解和释放金的热作用、形成高含金的有机热液，含金热液上移在构造通道中沉积并被有机碳再次吸附，最终形成金矿床，对金存在成矿作用。

The ameloblasts are the key cells during odontogenesis, and they have been already cultured in vitro. The amelogenin is the extracellular matrix synthesized and secreted by the ameloblasts, and it plays a crucial role during amelogenesis.

成釉细胞是牙器官形成的关键细胞，国内外已成功离体培养出成釉细胞，成釉细胞合成和分泌的细胞外基质－釉原蛋白在釉质的形成中起着关键作用。

The immunohistochemical location of noncollagenous protein, bone sialoprotein , osteopontin and osteocalcin at different stages following periradicular surgery was undertaken. The crystals formation on surfaces of MTA was evaluated when treated in different conditions without cells in vitro and in vivo. MTA was used to manage clinical problems, including perforations in roots or furcations, and pulpless permanent teeth with incomplete root formation. The study included the following three parts

本研究试图通过体内外研究探讨MTA表面牙骨质形成的机理，动物体内动态观察根尖周组织在用MTA倒充填后的组织反应和细胞外基质非胶原蛋白的表达，体外观察MTA在不同的环境下表面的形态及成分变化，和在体内环境下材料表面磷灰石层的形成，同时结合临床病例观察其临床治疗效果。

At last, in Ansys 9.0 software, by Boolean operation, different parts of the crown （ enamel, dentin and pulp cavity） were separated, and the 3D meshes were created respectively.

再将模型导入Geomagic7软件中进行精修和细化，形成有限元分析软件可识别的实体三维模型，最后，将牙体组织的三维实体模型在Ansys9.0软件中进行布尔运算，区分出釉质、牙本质及髓腔系统，并分别进行了网格划分。

This usually extends quite far, and in males may reach beyond the lip line. The tusk grows from its base as fresh dentine is slowly deposited over the surface of the pulp cavity.

此肉囊的范围较大，雄性可达到唇边，象牙由牙根开始生长的嫩牙首先在牙座部位缓慢形成。

objective to evaluate clinical effect of the handling protaper nickel-titanium rotary instruments in preparation of canals of posterior teeth.methods 96teeth with pulpitis or periapical periodontitis were instrumented by handling protaper rotary instruments using step-down technique,and by k files using step-back technique for control.all teeth were obturated with lateral condensation methods.the efficiency of preparation was analyzed with ra-diographs before and after operation.results no transportation,apical blockage and ledge were found in test.the technique could keep canals smooth.there were two ledge,one instrument fracture and nine transportation in control.the operative time was shorter and post treatment pain seldom occurred in handling protaper group.conclusion the handling protaper niti rotary instruments can prepare the canals effectively and safety.after the preparation,the canals could be easily washed,sterilized and filled.it is an efficient instrumentation method for posterior teeth's canals and be used widely.

目的 评价手用protaper预备后牙根管的临床效果。方法选取患有牙髓炎和根尖周炎的后牙96例，随机分成试验组和对照组各48例，试验组用手用protaper多锥度镍钛旋转器械逐步伸入法预备根管，对照组用k锉，逐步后退法预备根管，两组均用侧向加压充填法充填根管，根据治疗前后的x线片，评价后牙根管预备效果。结果试验组无根管偏移、根尖阻塞、台阶，且根管壁平滑流畅，无器械折断等并发症发生。对照组有2例台阶形成，器械折断1例，根管偏移9例。试验组操作时间短且术后疼痛轻微。结论应用手用protaper预备后牙根管快速、安全，成形效果好，易于根管冲洗消毒及填充，可视为临床上预备后牙根管的有效方法。

BACKGROUND: Studies demonstrated that incisor continuously growing is due to lack of epithelial root sheath formation. However, researches regarding whether receptor activator of nuclear factor κB ligand and osteoclast has correlation with continue root development is poorly understood.

背景：研究表明小鼠不断生长的切牙是由于切牙仅有颈环而无上皮根鞘的形成，但是破骨细胞分化因子核因子κB受体活化剂配体和破骨细胞与不断生长的牙根发育是否相关，目前研究较少。

In the treatment of impacted third molar, dental practioner and oral surgeon more often think about how to extract the third molar completely, but rarely consider to add some procedures such as distal wedge, alveoloplasty, guided tissue regeneration, and apically repositioned flap etc., to prevent 2nd molar from developing periodontitis. The latter procedures can reduce its accompanying deep pocket, to remove plaque and calculus on its diseased root surface.

在治疗阻生第三大臼齿，诊所执业医师和一般口腔外科医师较常会考虑怎样把阻生第三大臼齿完全拔除，但却较少考虑在拔除阻生第三大臼齿的同时做一些措施，像远心楔形手术，齿槽骨整形术，引导组织再生术和牙周办膜根向移动术等来预防第二大臼齿远心端形成牙周炎，或同时替第二大臼齿治疗深的牙周囊袋和去除其牙根表面的牙结石和牙菌斑。

Because of fetal growth and development and maxillofacial region as early as the third week of embryonic development began, the deciduous tooth germ in the second month of pregnancy will be begun to take shape.

因为胎儿颌面部的生长发育早在胚胎发育的第三周就开始了，乳牙的牙胚在怀孕的第二个月便开始形成。

And Pharaoh spoke to Joseph, saying, Your father and your brothers have come to you.

47：5 法老对约瑟说，你父亲和你弟兄们到你这里来了。

Additionally, the approximate flattening of surface strip using lines linking midpoints on perpendicular lines between geodesic curves and the unconditional extreme value method are discussed.

提出了用测地线方程、曲面上两点间短程线来计算膜结构曲面测地线的方法，同时，采用测地线间垂线的中点连线和用无约束极值法进行空间条状曲面近似展开的分析。