外斜线相连，与下颌第一磨牙根尖不相通连。
The fistula was connected with mandibular body but the first molar.
目的评价保存治疗纵折下颌第一磨牙的临床疗效。
Objective To evaluate the clinical effect of preserving the lower first molar with complete vertical fracture.
目的分析活髓下颌第一磨牙根纵裂的解剖学病因。
Objective to study the anatomical factors of vertical root fractures (VRFs) on vital pulp of maxillary first molar.
目的：了解上下颌第一磨牙牙釉质及牙本质的厚度。
Objective: To measure the thickness of enamel and dentin of the first molars.
颊瘘与外斜线相连，与下颌第一磨牙根尖不相通连。
The fistula was connected with mandibular body but the first molar.
交互牵引结合固定平面导板是矫治下颌第一磨牙舌倾的有效方法。
Clinical application of intermaxillary traction and fixed flat bite-plate could correct lingual inclination of mandibular molar effectively.
目的探讨下颌第一磨牙根管治疗术并发急性炎症的原因和防治措施。
Objective To study the reason and preventive means of the acute inflammation during root canal therapy of submandibular first molar.
前言：目的：建立下颌第一磨牙牙体缺损及修复的三维有限元模型。
Objective: to construct of 3-dimensional finite element models of mandibular first molar with structure defect restoration.
结论采用半切术技术保留下颌第一磨牙远中根的修复可获得满意效果。
Conclusion The hemisection can get satisfactory effect to repair the first mandibular molar with distal tooth reservated by selecting suitable tooth.
目的：评价直接数字化影像技术在下颌第一磨牙牙根纵裂诊断中的作用。
Objective:To evaluate the contribution of radiogram in diagnosis of primary vertical root facture in mandibular first molar.
目的观察下颌第一磨牙半切术后两种双端固定桥修复对牙槽骨应力分布的影响。
ObjectiveTo observe the effects of the two kinds of rigid fixed bridge design on the stress of the alveolar bone of mandibular first molar after hemisection.
方法用两组牙根解剖形态不同的下颌第一磨牙建立下颌第一磨牙即刻种植即刻负重的三维有限元模型。
Methods Two groups of first mandibular molars with different root morphology were used to establish the model after immediate implant, and immediate loading of the first mandibular molars were built.
在计算机上建立了下颌第一磨牙三维有限元模型，总节点为63 715个，4面单元数为41 676个。
The three dimensional finite element method models of the mandibular first molar was constructed on the computer, which had 63715 nodes and 41676 tetrahedrons elements.
方法：用电子测量尺测量23颗上颌第一磨牙和18颗下颌第一磨牙牙合面不同部位牙釉质、牙本质的厚度。
Methods: The thickness of enamel and dentin at different positions of 23 upper first and 18 lower first molars were measured by electronic ruler.
方法：观察下颌第一磨牙陈旧性拔牙间隙29处。测量矫治前后该处牙槽嵴高度，将测量值进行配对t检验。
Method: 29 lower first molar Spaces were observed and the height of alveolar crest before and after treatment were analyzed with paired-t tests.
分别在垂直载荷和斜向载荷下观察下颌第一磨牙磨牙半切术后不同固定修复设计对牙周支持组织应力分布情况。
The stress distribution of the reserved root with different prosthodontic design after hemisection therapy under the vertical loading and obliquely loading was observed.
结果得到右侧上下颌14颗牙的牙动度参数的正常范围，其牙动度参数的均值以下颌前牙最大，下颌第一磨牙最小。
Results All parameters of 14 teeth were achieved The parameter of TM in mandibular incisor was the highest and in mandibular first molar lowest.
方法：从6颗离体的形态正常的人右下颌第一磨牙中，选取密合度最好且形态接近临床要求的1颗进行根管治疗，制作制锁式的带桩嵌体修复体。
METHODS: 1 of the 6 first mandibular molars on the right side with normal morphology in vitro was selected for pulpectomy, which was the best in density and near to clinical requirement in morphology.
结果保存修复的成功率下颌第一恒磨牙为94％，第二恒磨牙为67％。
Results The successful rate of conservative prosthetics was 94% in the first mandibular molars, while 67% in the second molars.
结论：山羊下颌无牙区及下颌第一前磨牙区可作为牵张成骨增高牙槽嵴新的实验动物模型。
CONCLUSION: the no tooth area and the first premolar area of mandible in sheep is a good experimental animal model for alveolar ridge augmentation by distraction osteogenesis.
特别是在下颌第一恒磨牙。
安氏II1牙合下颌各牙根尖主应力值均略大于正常牙合，且最高应力值由第一磨牙近中根尖处移至最后一个磨牙根尖处。
The highest value of all apical areas were in the last molar in Angle II1 model instead of medial root of the first molar in normal occlusion.
目的：统计分析下颌第一、第二、第三磨牙牙冠近远中宽度、牙体长度、分根情况以及相关因素。
Objective: Statistical analysis of mandibular molar mesiodistal crown width and tooth length and development of root.
恒牙萌出于6岁左右，开始于第一恒磨牙以及下颌第一中切牙。这个过程一直持续到将近21岁。
Permanent teeth begin appearing around age 6, starting with the first molars and lower central incisors. This process continues until approximately age 21.
而且，下颌神经管在下颌第一或第二磨牙区走行与下颌下缘基本成平行状。
At 1st or 2nd molar region the mandibular canal was basically parallel with the inferior margin of the mandible.
而且，下颌神经管在下颌第一或第二磨牙区走行与下颌下缘基本成平行状。
At 1st or 2nd molar region the mandibular canal was basically parallel with the inferior margin of the mandible.
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