磨牙

The first three largest number of missing teeth is as follows: maxillary first molar, maxillary second molar and mandibular first molar. The first three largest number of resident teeth is as follows: mandibular cuspid, mandibular bicuspid and maxillary cuspid. The cases without occusal relationship account for 19.51%; and the cases which need occlusal reconstruction or occlusal elevation account for 19.51% of all the cases, while food impaction exists in 21.84% cases.

结果：本组老年人平均缺失牙齿9.10颗，缺失最多的前3位牙齿是上颌第一磨牙、上颌第二磨牙和下颌第一磨牙；余留最多的前3位牙齿是下颌尖牙、下颌第一双尖牙和上颌尖牙。19.51%的病例颌骨间无咬合接触关系，19.51%的病例修复时需咬合重建或咬合抬高；21.84%的病例修复前存在食物嵌塞。

The following values was measured: angle of cusp line between the second and third molar, impact state and depth, distance from Rickett's Xi to distal cusp of third mandibular molar along the occlusal plane, anterior border of ramus to the third mandibular molar, distance from projection of distal contact point of maxillary third molar to intersection of pterygoid vertical on occlusal plane.The change between pre-and post-treatment was calculated and analyzed with SPSS10.0 software package.α angle, Xi-LTM, R-LTM, R-LTM were tested with independent-sample t test, impact state and depth was tested with Chi-square test. Influence of age on the values was also evaluated.

测量治疗前后的第二、第三磨牙牙尖连线角度、阻生状态和深度，Rickett's Xi点到下颌第三磨牙远中尖距离、下颌支前缘到第三磨牙远中尖距离、翼上颌裂切线到上颌第三磨牙后缘的距离及上、下磨牙的前移量，计算治疗前后各变量的差值，采用SPSS10.0软件包进行统计学分析，α角、Xi-LTM、R-LTM、R-LTM用t检验，阻生状态和深度用χ^2检验，比较年龄因素对各指标的影响。

Results maxillary first and second molars were more mesially inclined in the first group, particularly in the younger subjects (16～25 years). this inclination increased with age. the logistic regression showed that the sagittal inclination of the first molar is a predictor of the eruption of the third molar.

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。logistic回归结果显示第一磨牙的轴倾度是第三磨牙萌出的一个预测因子。

Methods:7 cases of classⅡ,division 1 maloclusion were treated.Upper first premolar and lower second premolars were extracted in all cases.Lower first molars were mesially moved by means of segmental arch. Cephalometric analysis was used to evaluate the effects of the treatment.

应用片段弓技术对7例安氏Ⅱ类1分类患者，通过拔除上颌第一前磨牙及下颌第二前磨牙，使下颌第一磨牙较快地向近中移动，纠正磨牙Ⅱ类错牙合关系。

Anchorage loss measured at the first premolar averaged 1.3 mm,but the crowns tipped 3.5?distally.During distalization with Distal jet,the first premolar did not tend to tip mesially as found in many investigation of other intraoral distalizing appliance.

每侧第一前磨牙的支抗丧失平均为1.3mm并伴3.5 的牙冠远中倾斜，这一结果不同于其它口内磨牙远移装置所造成的前磨牙牙冠近中倾斜，与国外对同类矫治器的观察结果相似。

In pendulum appliance group: the velocity of maxillary first molar distalizing was 0.8mm per month, distal tipping 12.6°,buccal move 0.5mm, horizontal rotation 2.8°; maxillary central incisor move mesially 0.5mm. Conclusion Two methods successfully distalized maxillary molars to appropriate positions.

钟摆矫治器组上颌第一磨牙平均远中移动3.5mm，疗程4.2个月，平均移动速度0.8mm/月；磨牙长轴向远中倾斜角度12.6°；磨牙颊向移位0.5mm；磨牙发生远中舌向水平旋转约2.8°；上颌中切牙切端向远中移动0.5mm。

The clinical characters of oligodontia concluded from this study are following:(1) There is significant difference that more teeth absent and more existent teeth anomalies in patients of oligodontia/S group than in patients of oligodontia/I group, and the peg-shaped upper lateral incisor is the most frequently affected teeth with shape anomaly.(2) Both of the two groups have no significant differences in number of teeth missing between maxilla and mandible as well as that between left and right side.(3) The distribution of teeth missing is bilateral symmetry in both groups, but the frequency of teeth lost are different: excluding the third molar, in oligodontia/I group, the lower second premolar is the most frequently congenitally missing tooth followed by the upper lateral incisor, while in oligodontia/S group, the most frequently missing teeth are mandibular canine and maxillary lateral incisor. Nevertheless, the first molars are the most stable teeth in both groups.(4) In oligodonita/I group, the mean mesiodistal dimensions of all type of existent teeth are significantly smaller than normal value. It is implied that oligodontia is not an isolated phenomenon, but is related to a complex of other dental changes.

对于口腔多个恒牙先天缺失的临床特点有以下初步结论：(1)综合征型先天缺牙患者较单纯型先天缺牙患者恒牙缺失数目更多，平均分别为23.9个和14.9个，且现存牙齿有更多的形态异常，分别为7／10例（70％）和6／22例（27.3％），其中最常见的是上颌侧切牙畸形；(2)两种类型的多个恒牙先天缺失患者的缺牙数目在上下颌及左右侧之间均无差别；(3)两种类型的多个恒牙先天缺失患者在缺失牙位上均呈对称分布，但在具体牙位上有所差异：不计第三磨牙，单纯型先天缺牙最常缺失的牙位是下颌第二双尖牙、其次为上颌侧切牙；而综合征型先天缺牙最常缺失的牙位是下颌尖牙和上颌侧切牙；无论何种情况，第一磨牙均为牙列中最稳定的牙齿；(4)在单纯型先天缺牙患者中，现存恒牙的牙冠宽度较国人正常值偏小，差异显著，提示牙齿形态与多个牙先天缺失有一定相关性。

Methods: Fifty-fix adolescents were chosen and divided into first premolar extraction and nonextraction groups, with 30 and 26 patients respectively. The pretreatment and posttreatment panoramic radiographs were taken. The indexes of third molar eruption space, distance from third molar to occlusal plane and the length of mandible were measured and analyzed.

选择56例上下颌第三磨牙均存在的患者进行方丝弓正畸治疗，按照第一前磨牙拔除与否分为拔牙组（30例）和非拔牙组（26例），利用术前术后曲面断层片对患者上下颌第三磨牙萌出间隙、第三磨牙与胎平面的距离以及下颌长度进行测量分析。

Thirty-six rats ,weighing(250±10)g, were randomly divided into normal group, experimental group and control group.Orthodontical devices were put between the upper incisor teeth and dens molaris in both experimental group and control group.The corrective force was adjusted to 60g.Salvia miltiorrhiza combination was implanted to each rat in the experimental group every day.The animals of both experimental group and control group were killed at 7,14 and 21 days.The upper dens malarias and periodontal tissue slices were observed under the light microscope and transmission electro microscope,and the X-ray dental films were taken and measured with digitization dental scanning apparatus and its software.

以36只体重(250±10)g的雄性大鼠为样本，随机分为正常组、实验组和对照组，设定不同浓度丹参复合膜，以同体对照方式在正常组进行体内植入实验，在2周内观察不同浓度丹参的牙周组织诱导作用，寻找最佳应用浓度；在实验组和对照组的上切牙与磨牙之间隙安装正畸装置，建立大鼠磨牙移动实验模型，矫治力的大小为60g；实验组每日每只体内植入丹参复合生物膜，两组动物于正畸加力7、14、21d，分三批处死；处死后立即切取双侧上颌磨牙及牙周组织制取标本，制片透射电镜和光镜观察；拍摄X线牙片，用数字化牙科扫描仪及软件对其进行测量分析。

The corrective force was adjusted to 60g.Salvia miltiorrhiza combination was implanted to each rat in the experimental group every day.The animals of both experimental group and control group were killed at 7,14 and 21 days.The upper dens malarias and periodontal tissue slices were observed under the light microscope and transmission electro microscope,and the X-ray dental films were taken and measured with digitization dental scanning apparatus and its software.Result:The most fitting concentration of combined biological membrane was 0.80g;the speed of the remodeling of the periodontal tissue at the compression side in the experimental group was faster than that of the control group.

以36只体重(250±10)g的雄性大鼠为样本，随机分为正常组、实验组和对照组，设定不同浓度丹参复合膜，以同体对照方式在正常组进行体内植入实验，在2周内观察不同浓度丹参的牙周组织诱导作用，寻找最佳应用浓度；在实验组和对照组的上切牙与磨牙之间隙安装正畸装置，建立大鼠磨牙移动实验模型，矫治力的大小为60g；实验组每日每只体内植入丹参复合生物膜，两组动物于正畸加力7、14、21d，分三批处死；处死后立即切取双侧上颌磨牙及牙周组织制取标本，制片透射电镜和光镜观察；拍摄X线牙片，用数字化牙科扫描仪及软件对其进行测量分析。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。