磨牙

Results The incidence of wedge-shaped defects reached 97.3 %,and the frequency of involved teeth was:first premolar,second premolar,first molar,cuspid.

结果 该组老年人楔状缺损的发病率为97 。3 %，且随年龄递增；楔状缺损的好发部位和缺损程度第一双尖牙列首位，其次为第二双尖牙，第一磨牙；其中第一磨牙比以往人们认为的尖牙更好发楔状缺损。

Paleoanthropologist David Strait of the University at Albany in New York state and his colleagues found that A. africanus evolved jaws, teeth, and a face that would have been particularly good at withstanding large forces on its premolars—precisely the place where humans and other primates crack large objects, such as nuts that are too big to chew with our molars.

纽约州奥尔巴尼大学古人类学家戴维·斯特雷特和他的同事发现，南方古猿非洲种的颌骨、牙齿和脸经过演化，其前磨牙特别擅长经受极大的力气——人类和其他灵长类动物恰好就用前磨牙来咬碎像坚果一样的大块食物，大到我们的磨牙无法咀嚼。

The longest time was 22 months.the shortest time was 12 months. Conclusion The extraction planing of missing the first molars in class Ⅰmalocclusion is different from routine extraction mode.This clinical study indicated that it should chose nimble planing and for decurtate treatment time,according to arch crowding, profile and existing of the third molars.

第一磨牙缺失的患者在I类错牙合畸形中的拔牙模式有别于常规，要根据患者牙弓的拥挤程度，面型突度及有无第三磨牙等情况选择治疗计划和有利于缩短疗程的矫治方法。

RESULTS:①There was higher tensile stress at the ingual side of symphysis, inside of molar and outside of condyle under the impact of chin.②There was higher tensile stress at the lingual side of symphysis, inside of contralateral molar, outside of contralateral angle, outside of homolateral angle and inside of homolateral body under the impact of body.③There was higher tensile stress at the inside of angle, inside of homolateral condyle, lingual side of symphysis, outside of contralateral condyle and inside of homolateral molar under the impact of angle.

结果：①撞击颏部，其舌侧区，磨牙后区内侧面、髁状突颈外表面以及下颌角外表面具有较高的张应力；②撞击下颌体部，颏部舌侧区，对侧磨牙后区内侧面、对侧下颌角外表面、撞击侧下颌角外侧面、撞击侧体部内侧面具有较高的张应力；③撞击下颌角，其内侧面、撞击侧髁状突颈内侧面、颏部舌侧面、对侧髁状突颈外表面以及撞击侧磨牙后区内侧面具有较高的张应力。

Results Maxillary first and second molars were more mesially inclined in the first group, particularly in the younger subjects (16～25 years).

用U检验对两组测量角度的平均值进行比较，Spearman 相关系数估计年龄因素的影响，用Logistic回归分析第三磨牙的萌出与第一磨牙、第二磨牙的轴倾度、性别和年龄之间的关系。

Results Maxillary first and second molars were more mesially inclined in the first group, particularly in the younger subjects (16～25 years).

结果 上颌第三磨牙萌出组与未萌出组相比，上颌第一磨牙和第二磨牙更向近中倾斜，而且随年龄的增加倾斜度也变大。

Upper central incisors moved forward and downward together with maxillary, at the same time they upright in the sagittal plane and tip mesially. 3 The occlusion plane rotated clockwise for about 1.5°. 4 The width increasement effect of RME comes from approximately the equal amounts of skeletal and dental expansion. The mode of dental movement was a combination of body and tipping movements of posterior teeth.

结果：1后牙在宽度方向上为整体移动和倾斜移动相结合的移动方式，但第一磨牙和第一双尖牙稍有差别；牙齿和骨对宽度增加的贡献各占约1/2；2后牙在垂直方向有伸长的趋势；3第一磨牙和第一双尖牙均向前整体移动，轴倾度保持不变；4中切牙整体随上颌骨前部向前向下移动，其牙长轴发生直立，轴倾度增加；5上颌平面发生顺时针旋转。

Objective To explore the effective method of eliminating the tissue damages of tooth,pericementum and temporomandibular joint caused by children s bruxism.

目的 探讨解除儿童磨牙症对患者牙体、牙周、颞颌关节等组织损害的有效方法。方法采用自行研制的软树脂牙合垫给 96例磨牙症患者配戴，观察其疗效，并与 82例配戴硬塑料牙合垫者进行比较。

They were divided into two groups, and operated pulpotomy using formocresol and ferric sulfate respectively. The children were followed up after 6 months and 1 year. Successful rates of pulpotomy were summarized statistically.

选择3~5岁儿童的第一乳磨牙、4~6岁儿童的第二乳磨牙共45人，80颗乳磨牙深龋近髓的病例，随机分为两组，分别行甲醛甲酚和硫酸铁溶液牙髓切断，术后6个月及1年复查，分别统计两组成功率，比较两组的疗效差异。

Methods: 80 primary molars with deep caries close to the pulps were selected. They were divided into two groups, and operated pulpotomy using formocresol and ferric sulfate respectively. The children were followed up after 6 months and 1 year. Successful rates of pulpotomy were summarized statistically.

选择3~5岁儿童的第一乳磨牙、4~6岁儿童的第二乳磨牙共45人，80颗乳磨牙深龋近髓的病例，随机分为两组，分别行甲醛甲酚和硫酸铁溶液牙髓切断，术后6个月及1年复查，分别统计两组成功率，比较两组的疗效差异。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。