切牙

Based on this background, maxillary central incisors was prepared as residual roots model, the materials which has the similar physical properties and capabilities as that of the alveolar bone and periodontal membrane respectively were chosen.

基于上述情况，本实验以人离体上中切牙制备实验模型，以力学性能近似的材料模拟牙槽骨、牙周膜和桩冠修复后的上前牙，制作与上前牙口内受力角度相同的夹具及压力头，形成加载测试系统。

Stress distribution of the natural periodontal membrane, bionic periodontal membrane and the bone interface of the three models are calculated out by SuperSAP93, when the same load exerted to the three models. Results The stress change of the inside and outside surface of the natural periodontal membrane and bionic periodontal membrane is in the same tendency.

应用螺旋CT对上颌中切牙标本进行扫描，分别建立仿生种植牙、天然牙和骨性结合种植体模型，对3个模型施加同样的载荷，应用Super SAP93软件，计算出天然牙周膜和仿生牙周膜以及3种模型骨界面上的应力分布。

Therefore, in a newly designed three-dimensional cell culture system that fulfils the conditions necessary for odontoblast differentiation (Kikuchi et al. 2002), we examined whether dental papilla cells in rat mandibular incisors could differentiate into tubular dentine-forming cells.

本实验我们设计了另一种新的三维培养模型，来研究成牙本质细胞的分化，并观察大鼠下切牙牙乳头细胞能否形成管状牙本质。

Result:One case originated from the supernumerary teeth on the floor of left nasal cavity, and the other left reversed lateral incisor.

结果：1例起源于左鼻腔底额外牙的含牙囊肿，另1例起源于左鼻腔底倒生侧切牙的含牙囊肿，均有同侧上唇、鼻旁的反复肿胀史。

The color of the maxillary anterior teeth is related to tooth position, the central incisor is the lightest but the canine is the darkest, and the canine is redder, yellower, and has the highest Chroma

上前牙的颜色与牙位有关，中切牙的亮度最大而尖牙最暗且颜色更偏红、偏黄，饱和度也最大

Results: After 6~7 months the dentures in crowded patients were arranged neatly, the upper first molars were moved 0.31mm mesially evenly, and the upper incisors were moved 0.20mm labially evenly.

结果：成人牙列拥挤患者6～7个月后牙列排齐整平，上颌第一磨牙向近中整体前移，其冠部平均前移了0.31mm，上颌切牙冠部向唇侧平均倾斜移动约0.20mm。

During en mass retraction of upper anterior teeth with straight wire technique, the length of anterior hook mainly influenced anteroposterior moving pattern of anterior teeth. As anterior hook increased from 0 to 6mm, labiolingual displacements of lateral incisor varied form lingual tipping to lingual translation and lingual controlling root movement, while 3-D displacements of other teeth only increased in account.

3直丝弓矫治技术整体内收上前牙时，牵引钩的长度主要影响前牙的矢状向位移方式：牵引钩长度增加至6mm的过程中，除侧切牙在唇舌向上由舌向倾斜运动变为舌向整体平移和舌向控根运动外，前牙的三维位移只有数量的增大，趋势基本保持不变。

After being loaded with horizontal retraction force at various height, displacement and stress distribution of anterior teeth was not well-distributed. Labiolingual displacement of incisors varied from crown lingual tipping to lingual translation and lingual controlling root movement, while canine mainly showed crown lingual tipping. The displacements of teeth increased with the length of hook but their moving tendency remained unchanged. Stress distribution in PDL was in accordance with teeth displacement.

2水平向后牵引力的作用点升高时，上前牙的位移和应力分布趋势各不相同：切牙的唇舌向位移由冠舌向倾斜逐渐变为舌向整体移动和舌向控根移动，尖牙则以冠舌向倾斜位移为主；前牙位移量随牵引力高度增加而增大，但位移趋势较为稳定；牙周膜应力分布与其位移趋势相一致。

After 4~8 months, in adult bimaxillary protrusion patients, cuspids were moved to distal, the upper first molars were moved 1.12mm mesially evenly, and the upper incisors were moved 7.91mm palatelly evenly.

成人双颌前突患者在4～8个月后远移尖牙到位，拔牙间隙基本关闭，上颌第一磨牙为近中整体前移，其冠部平均前移了1.12mm，上颌切牙冠部平均向腭侧倾斜移动约7.91mm。

Its mechanism is downward and backward rotation of the mandible, the retrusion of the lower incisors, the protrusion of the upper incisors and the forward growth of maxilla.

FR-Ⅲ是矫治替牙期前牙反的理想方法之一，其机理是下颌骨向下、向后旋转，舌倾下切牙，唇倾上前牙，促进上颌骨向前生长。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。