前磨牙

PURPOSE: To study the influence of the first premolar extraction on the angulation and eruption space of third molar.

目的：探讨拔除第一前磨牙正畸治疗后对第三磨牙角度和萌出间隙的影响。

The length, width, axial gradient for the crowns,the heigh of gingival line,the width of anterior dentition and the ratio of crista marginalis of their teeth were measured and analysed in their photographs and dental casts after orthodontic treatment.

测量关于正畸治疗后上颌第一前磨牙和对侧尖牙的龈缘线高度和牙齿形态的6项指标：龈缘线高度、临床冠长度、宽度、单侧前牙列宽度、轴倾度和近远中边缘嵴比，进行两均数配对t检验，观察分析两组的差异。

Methods 20 human biscuspids scheduled to be extracted for the orthodontic reasons were prepared for porcelain fused to matal crown,of which every 2 teeth were from the same patient and the same jaw. The teeth were randomly, blindly and selfcontrolly divided into 2 groups.In the control group:the temporary crowns were cemented with zinc oxide cement.In the testing group:Green Or was applied before the temporary crowns were cemented with zinc oxide cement.

要领 选择因正畸治疗必要而打算撤废的20颗前磨牙举办金属烤瓷全冠牙体准备，其中每2颗牙均为同颌同名牙；授与随机、双盲、自身比较计划分为2组：比较组在牙准备体上直接用氧化锌丁喷香酚水门汀粘固且则冠；不雅察看组在牙准备体上涂布极固宁TM后用氧化锌丁喷香酚水门汀粘固且则冠。

Methods 20 human biscuspids scheduled to be extracted for the orthodontic reasons were prepared for porcelain fused to matal crown,of which every 2 teeth were from the same patient and the same jaw. The teeth were randomly, blindly and self controlly divided into 2 groups.In the control group:the temporary crowns were cemented with zinc oxide cement.In the testing group:Green Or was applied before the temporary crowns were cemented with zinc oxide cement.

选择因正畸治疗需要而计划拔除的20颗前磨牙进行金属烤瓷全冠牙体预备，其中每2颗牙均为同颌同名牙；采用随机、双盲、自身对照设计分为2组：对照组在牙预备体上直接用氧化锌丁香酚水门汀粘固暂时冠；观察组在牙预备体上涂布极固宁TM后用氧化锌丁香酚水门汀粘固暂时冠。

The retention of the clasp on molar is greater than premolar in the same condition of undercut.

相同倒凹条件下，磨牙卡环的固位力比前磨牙卡环大。

Methods:Select 11～18 year old patients with bimaxillary protrusion 20 cases were randomly divided into two groups:TPA group,TPA＋Nance arch group.Two cases are the uprooting of four first premolars,the use of straight wire appliance technology,one step closure extraction gap analysis before and after treatment lateral skull X ray film and dental cast changes in the indicators.

选取11～18 岁双颌前突患者20 例，随机分为：TPA与TPA＋Nance弓两组；两组病例均拔除4个第一前磨牙，使用直丝弓矫治技术，一步法关闭拔牙间隙，分析治疗前后X线头颅侧位片及牙颌模型的各项指标变化。

For each subject, the buccolingual bone thickness was measured by postulating that the miniscrews would be inserted at 16 positions (10, 12, 14 and 16 mm above the median sagittal planes of the interradicular spaces between the first molars and the second premolars in the maxilla, and 30°, 45°, 60°, 90° from the cortical bone surface).

在重建后的锥形线束CT影像上测量上颌第二前磨牙与第一磨牙牙根间矢状面上距离参考平面10，12，14，16 mm的4个植入高度上，以与骨皮质表面成30°，45°，60°，90°的4个方向共16个部位的颊舌侧骨质厚度，计算各植入部位触及上颌窦的危险率，在骨厚度大于6 mm的植入部位模拟植入微螺钉种植体并测量其周围骨质密度。

Methods The Chatillon force measuring instrument was used to record the retention of gold alloy casting Akers clasps when they were dislodged from the undercuts of different depths (0.25 mm, 0.375 mm, 0.50 mm and 0.75 mm) on the premolar and molar. All data were analyzed by ANOVA.

采用Chatillon测力仪，测定临床常用金合金铸造三臂卡在磨牙和前磨牙的0.25、0.375、0.50、0.75 mm倒凹深度上的固位力，同时进行统计学分析。

Animals were divided into control group and 5 experimental groups. Each experimental group had 2 canines and the central of masseters and geniohyoid were dissected out in 5th, 10th day in distraction and 2nd, 4th, 8th week after distraction.

牵张器采用口内下颌骨牵张器，截骨部位在第三乳前磨牙与第一恒磨牙间且垂直于下颌骨下缘，牵张方向为前后向。

Base on the stress analysis, the model with unit of porcelain to metal at the labiocervical margin is better than the models with porcelain or metal only at labiocervical margin for upper central incisor restoration.

从受力分析的角度而言，金属颈环型设计适应于前磨牙和后牙的修复：瓷颈环型设计适应于前牙修复，而金-瓷混合颈环型设计则适应于任何形式的修复体。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。