The root canals in mandibular first premolars failed to be treated;
目的 确定人上颌第一前磨牙的颊舌向根管弯曲程度和情况。
Methods 60 human premolars were selected and divided into six groups by random.
方法收集离体人前磨牙60个，随机分成6组。
Absence of more than two first premolars or absence of a first and a second premolar.
缺少超过两个第一前臼齿或者一个第一和一个第二前臼齿。
Methods 20 subjects were chosen with 4 first premolars extraction based on diagnosis.
方法选择拔除4颗第一双尖牙的患者2 0例，采用方丝弓技术治疗。
Objective: To investigate the root and canal morphology of extracted mandibular premolars.
目的：研究离体下颌前磨牙的牙根及根管形态。
Objective: To investigate the morphology of physiological foramen of mandibular premolars.
研究目的：探讨下颌前磨牙生理性根尖孔的形态特征。
Sealants are protective coatings placed over the tops of chewing teeth - molars and premolars.
封闭剂在是牙齿咀嚼面上覆盖一层保护材料——在磨牙或者前磨牙。
Conclusions: The roots of maxillary first premolars possesses a variety of canal system types.
结论：上颌第一前磨牙的根管类型相对复杂。
Objective To investigate the root and canal morphology of extracted maxillary second premolars.
目的观察上颌第二前磨牙的牙根及根管形态。
Objective To research the preserved effect with complex therapy of the fractured premolars and molars.
目的研究后牙折裂综合治疗后的保存效果。
Objective To investigate root canal curvatures of human maxillary first premolars in buccolingual directions.
目的研究上颌第一前磨牙根管颊舌向的弯曲情况。
Mandibular second premolars are the most frequently missing teeth while maxillary lateral incisors are second-most.
下颌第二前磨牙是最常见的缺失的牙齿，而上颌侧切是第二大。
Objective: to investigate the effect of cast post and core on the restoration of premolars and molars of extensive loss.
目的：探讨铸造金属桩核在后牙牙体大面积缺损修复中应用的临床疗效。
PURPOSE: to investigate the effect of root canal anatomy in maxillary first premolars on root canal treatment difficulty.
目的：探讨上颌第一前磨牙的根管解剖形态对根管治疗术难度的影响。
Most dentists recommend the permanent molars and premolars to be sealed because these are the teeth that have the deepest grooves.
大多数牙医建议封闭恒牙的磨牙和双尖牙，因为磨牙的窝沟比较深，乳牙通常不用做窝沟封闭。
Methods: Fresh health premolars were collected, divided into some groups according to age, embedded in paraffin and cut into slices.
方法：收集健康新鲜的前磨牙，按年龄分组，石蜡包埋切片，免疫组织化学与图像定量分析。
Objective: To study the application and protective function of all-ceramic onlay to restore the defect ofpermanent premolars and molars.
前言： 目的：探讨全瓷高嵌体修复后牙缺损的应用及其保护作用。
Objective: to observe the effects of different root canal file and the restoration of occlusal surface on the fracture resistance of premolars.
目的：观察不同根管锉预备根管及不同面充填物对前磨牙牙体抗折强度的影响。
Three pairs of incisors, one pair of elongated canines, three pairs of molars, four pairs of premolars, upper and lower, for a total of 44 teeth.
有三对门牙、一对延长犬齿、三对臼齿、四对前臼齿，上下加起来，一共。
Restoring of two premolars replace a molar that was residual root of separating was nice. The feasibility of this method was studied in this paper.
一个后磨牙分离残根以两个前磨牙修复效果理想，本研究旨在从理论上探讨这种修复方法的可行性。
Objective To compare the fracture resistance and failure modes of endodontically treated human upper premolars restored with different postcore systems.
目的比较不同桩修复离体牙对修复体整体抗折强度的影响。
AIM: To study the clinical manifestation of the molars and premolars of cracked teeth, and explore the cause of episode and the different treatment method.
目的：研究牙隐裂的磨牙及前磨牙的临床表现，探讨发病原因及不同的治疗方法。
Methods:28 human premolars extracted for orthodontic reasons were collected for the experiment. Every premolar was split vertically into medial and distal haves.
方法：收集临床上因正畸需要拔除的前磨牙28颗，将每个牙齿分为近中和远中两个邻面标本。
Results the predilection age of VRFs was over40 years old, the predilection teeth of VRFs were molars and premolars, and most teeth with VRFs had periodontal lesions.
结果牙根纵裂好发于40岁以上年龄，以磨牙及前磨牙较为多见，均伴有牙周损害。
Results: After treatment, in maxilla the arch width and alveolar bone width between canines were in creased(P<0.01), those were decreased between second premolars(P<0.01 ).
结果：上颌矫治后尖牙间牙弓宽度和基骨宽度明显增加（P< 0 .0 1） ，前磨牙间牙弓宽度和基骨宽度明显减小（P< 0 .0 1）。
To evaluate the effects of the different amount of residual tooth on the fracture resistance ability of lower premolars restored with fiber quartz-fiber post-core and full crown.
评价不同牙体剩余量对石英纤维桩复合树脂核全冠修复下颌前磨牙抗折性能的影响。
Conclusion This reflects that the second molars could move mesially during treatment in the second premolars extraction subjects, which can lead to the increase of the retromolar space.
结论：第二前磨牙拔除患者可发生第二磨牙近中移动，导致磨牙后间隙增加。
This paper illustrated the characters about root canal morphology of mandibular premolars, including the formation, configurations, racial difference, classification and methods for study.
本文简要介绍下颌前磨牙多种解剖结构的形成、形态特点、人种差异、分型和研究方法。
Methods The 60 premolars were made into test pieces and embedded with resin. One side was exposed as a test surface, with its enamel removed and superficial dentin polished with sandpaper.
方法将因正畸需要拔除的60颗前磨牙制成试样块并用树脂包埋，一面暴露作为测试面，去除其釉质暴露浅层牙本质并用砂纸磨平。
Methods The 60 premolars were made into test pieces and embedded with resin. One side was exposed as a test surface, with its enamel removed and superficial dentin polished with sandpaper.
方法将因正畸需要拔除的60颗前磨牙制成试样块并用树脂包埋，一面暴露作为测试面，去除其釉质暴露浅层牙本质并用砂纸磨平。
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