安氏Ⅱ类错不同矫治模式对下颌第三磨牙萌出的影响

目的比较不同矫治模式下成人安氏Ⅱ类错牙合患者下颌第三磨牙萌出状况的变化,探讨不同治疗方式对下颌第三磨牙萌出的影响。方法选取90例成人安氏Ⅱ类错牙合患者,分为不拔牙组(30例)、拔除第一前磨牙组(30例)和拔除第二前磨牙组(30例),矫治前后分别拍摄曲面体层片,测量下颌第三磨牙倾斜角度及萌出间隙,预测其萌出情况。结果与不拔牙组相比,拔牙组矫治前后下颌第三磨牙倾斜角度显著改善(P<0.05)。拔牙组矫治前后下颌第三磨牙萌出间隙明显增大(P<0.05)。3组间矫治前后萌出间隙变化具有统计学意义(P<0.001),非拔牙组下颌萌出间隙差值大于拔除第一前磨牙组,而拔除第一前磨牙大于拔除第二前磨牙组。预测拔除第二前磨牙组下颌第三磨牙萌出关系最好,其次是拔除第一前磨牙组,最后是非拔牙组。结论拔除下颌前磨牙利于矫治后第三磨牙倾斜角度及萌出间隙的改善,拔牙位置越靠后,其改善越显著,萌出概率也越大。     

安氏I类错[牙合]非常规拔牙模式的矫治体会

目的：观察安氏I类错[牙合]拔除上颌第一前磨牙，下颌第二前磨牙后对支抗的不同需求，以及对咬合关系的影响。方法：选择安氏I类错[牙合]需减数治疗病例25例，拔除上颌第一前磨牙，下颌第二前磨牙后，常规直丝弓矫治器矫治。结果：25例均获得正常覆耠覆盖，尖牙和磨牙中性关系，患者侧貌发生明显改变。结论：安氏I类错[牙合]非常规拔牙模式可消耗下颌支抗，保护上颌支抗，更好地维护了磨牙的中性关系，使疗程缩短。     

前磨牙拔牙模式对前牙比正常的不同错(牙合)畸形矫治后全牙比的影响

目的：探讨前牙比正常的安氏3种分类经不同的拔牙模式治疗后全牙比的变化。方法：选取252例前牙比正常的患者模型，计算各组拔牙前和模拟4种模式拔牙后的全牙比，了解其变化规律。结果：相同拔牙模式的3种错（牙合）组矫治后的全牙比之间无大的差别；与拔牙前相比较，3种错（牙合）组拔牙后的全牙比均有所减小；在安氏Ⅰ类组与Ⅲ类组中，除了第2组（上下颌均拔除第一前磨牙）与第3组（上颌拔除第一前磨牙，下颌拔除第二前磨牙），第4组（上颌拔除第二前磨牙，下颌拔除第一前磨牙）与第5组（上下颌均拔除第二前磨牙）间全牙比的比较无显著性统计学差异外，其余组间的比较均有显著性差异；安氏Ⅱ类组，不同拔牙模式的全牙比之间均有显著性统计学差异。结论：前牙比正常的安氏不同错（牙合）畸形进行拔牙矫治时，前磨牙的拔牙模式会对拔牙后的全牙比产生影响。     

前磨牙拔牙模式对前牙比正常的不同错畸形矫治后全牙比的影响

目的:探讨前牙比正常的安氏3种分类经不同的拔牙模式治疗后全牙比的变化。方法:选取252例前牙比正常的患者模型,计算各组拔牙前和模拟4种模式拔牙后的全牙比,了解其变化规律。结果:相同拔牙模式的3种错牙合组矫治后的全牙比之间无大的差别;与拔牙前相比较,3种错牙合组拔牙后的全牙比均有所减小;在安氏Ⅰ类组与Ⅲ类组中,除了第2组(上下颌均拔除第一前磨牙)与第3组(上颌拔除第一前磨牙,下颌拔除第二前磨牙),第4组(上颌拔除第二前磨牙,下颌拔除第一前磨牙)与第5组(上下颌均拔除第二前磨牙)间全牙比的比较无显著性统计学差异外,其余组间的比较均有显著性差异;安氏Ⅱ类组,不同拔牙模式的全牙比之间均有显著性统计学差异。结论:前牙比正常的安氏不同错牙合畸形进行拔牙矫治时,前磨牙的拔牙模式会对拔牙后的全牙比产生影响。     

安氏I类错殆拔牙与非拔牙矫治后舌侧弓形对比分析

目的：比较安氏I类错殆拔牙与非拔牙矫治后的上颌舌侧弓形特点。方法：测量安氏I类错殆矫治后的上颌牙殆模型60副（拔牙与非拔牙矫治各30副）得出其舌侧牙弓宽度、深度的均值及标准差，测量结果进行统计学处理并绘制其舌侧弓形图作分析比较。结果：拔牙组前牙区舌侧牙弓宽度、深度均大于非拔牙组，差异有统计学意义（P〈0．05），前磨牙区舌侧牙弓深度拔牙组大于非拔牙组，差异有统计学意义（P〈0．001），宽度差异无统计学意义（P〉0．05）。2组的牙弓形态前牙区较一致，前磨牙、第一磨牙区2组差异较大，从第一磨牙远中舌尖向后弓形又趋于一致。结论：安氏I类错殆拔牙与非拔牙矫治后的上颌舌侧弓形整体形态相似，但拔牙组前部弓形较非拔牙组深。     

安氏Ⅰ类错矫治前后面部高度变化的比较

目的：分析安氏Ⅰ类错He患者拔除第一前磨牙与不拔牙矫治后面部高度的变化的比较。方法：选择27例安氏Ⅰ类错He拔除四个第一前磨牙患者，21例安氏Ⅰ类不拔牙患者，应用X线头影测量进行分析，其结果经SPSS统计软件进行数据处理。结果：矫治前后两组患者大多数投影测量项目显示矫治后面部高度呈非常显著性增加且两组之间无明显区别。结论：安氏Ⅰ类错He患者拔除四个第一前磨牙矫治与不拔牙矫治后面部高度均增加且无差异。     

安氏I类拔牙病例关闭间隙时切牙移动方式分析

目的:探讨安氏I类错牙合拔牙病例关闭间隙时切牙的移动方式。方法:安氏I类错牙合牙列拥挤病例20例,均拔除4个第一前磨牙,采用方丝弓细丝弓技术矫治,牙性支抗(弱支抗)。矫治前后摄X线头颅定位侧位片,对切牙位置及硬、软组织进行测量分析。结果:上颌切牙牙冠平均后移2.55mm;牙根平均后移0.20mm,下颌切牙牙冠平均后移1.78mm、牙根平均后移0.28mm。结论:牙性支抗控制下,安氏I类错牙合拔牙病例关闭间隙时切牙移动是有控制的倾斜移动。     

安氏Ⅰ类拥挤拔牙矫治后磨牙及切牙位置变化的研究

目的 :探讨安氏I类错牙合牙列拥挤经拔除 4个第一前磨牙矫治后磨牙及切牙位置的变化。方法 :选用泸州医学院附属口腔医学院正畸科连续收治的安氏I类错牙合牙列拥挤患者 2 0例 (男 8,女 12 ) ,年龄 14～16岁。均采用拔除 4个第一前磨牙 ,用方丝弓细丝弓技术矫治 ,牙性支抗。在矫治前后摄X线头颅定位侧位片 ,对磨牙及切牙位置进行测量比较分析。结果 :上颌磨牙牙冠平均前移 3 .15mm ,上颌切牙牙冠平均后移 2 .5 5mm ;下颌磨牙牙冠平均前移 4.3mm ,下颌切牙牙冠平均后移 1.78mm。结论 :牙性支抗 (弱支抗 )控制下 ,安氏Ⅰ类错牙合牙列拥挤拔牙矫治后上下磨牙及切牙位置均有明显变化 ,且相对RL线磨牙前移较切牙后移更大。     

安氏Ⅰ类错非常规拔牙模式的矫治体会

目的:观察安氏Ⅰ类错拔除上颌第一前磨牙,下颌第二前磨牙后对支抗的不同需求,以及对咬合关系的影响。方法:选择安氏Ⅰ类错需减数治疗病例25例,拔除上颌第一前磨牙,下颌第二前磨牙后,常规直丝弓矫治器矫治。结果:25例均获得正常覆覆盖,尖牙和磨牙中性关系,患者侧貌发生明显改变。结论:安氏Ⅰ类错非常规拔牙模式可消耗下颌支抗,保护上颌支抗,更好地维护了磨牙的中性关系,使疗程缩短。     

安氏Ⅱ类亚类错对称与非对称拔牙矫治后牙(牙合)关系的比较

目的 比较对称拔牙(拔除四个前磨牙)与非对称拔牙(拔除两个上颌前磨牙和一个下颌前磨牙)矫治安氏Ⅱ类亚类错(牙合)对牙关系的治疗效果.方法 收集20例已矫治完成的因单侧下颌磨牙远中错位所致的安氏Ⅱ类亚类错(牙合)患者,根据拔牙模式分为对称拔牙组和非对称拔牙组,每组各10例.对所有患者治疗前后的模型应用PAR(Peer A...     

Twin—block矫治器治疗年轻成人安氏Ⅱ^1错[牙合]的临床研究

目的探讨Twin—block矫治器（TB）矫治年轻成人下颌后缩型安氏Ⅱ^1错[牙合]的矫治效果。方法选取11例下颌后缩型安氏Ⅱ^1错[牙合]的年轻成人，采用Twin—block矫治器（TB）以及固定矫治器双期矫治。对治疗前后测量结果进行统计学分析。结果经TB治疗后，所有患者Ⅱ^1错[牙合]得到有效矫治：磨牙中性，覆殆、覆盖正常，侧貌面型明显改善。结论Twin—block矫治器可以有效矫治年轻成人下颌后缩型安氏Ⅱ^1错[牙合]．能使边缘性病例避免正颌手术。     

Mandibular dental changes following serial and late extraction of mandibular second premolars

Objectives:To determine changes in occlusal curves and dental tipping occurring from mandibular second premolar serial extraction, early extraction of deciduous mandibular second molars with missing second premolars, and late second premolar extraction compared with untreated controls.Materials and Methods:Information was collected from 85 subjects at three time points: T0, prior to serial extraction; T1, after serial extraction and drift prior to orthodontic treatment, and pretreatment for the late premolar extraction patients; and T2, posttreatment. Untreated age- and gender-matched controls were used for comparison. Three occlusal curves were measured on digitized mandibular casts, and dental tipping was assessed using lateral cephalograms.Results:At T0, there were no significant differences among groups. At T1, there was significant steepening of Monson''s sphere and the curve of Wilson between early and late extraction and control groups. At T2, the differences in Monson''s sphere and the curve of Wilson were fully corrected. At T1, there were significant differences in the tipping of mandibular 6''s, 4''s, and 3''s between the early extraction groups compared with the late extraction and control groups. At T2, these differences in tipping were fully corrected. There were no differences in mandibular incisor tipping between groups at T1 or T2.Conclusions:Serial extraction produced steeper occlusal curves and significant tipping of mandibular first molars, first premolars, and canines after extraction and physiologic drift (T1). Accentuated occlusal curves and tooth tipping were fully corrected following orthodontic treatment (T2). Mandibular incisor position was unchanged by serial or late second premolar extraction.     

Orthodontic treatment combined with mandibular distraction osteogenesis and changes in stomatognathic function

We performed an orthodontic treatment combined with mandibular distraction osteogenesis in a 15-year-old patient who wanted a correction of a chin deficiency and a protruding upper lip. The patient had an Angle Class II division 1 malocclusion with mandibular retrusion, a low mandibular plane angle, and scissors bite. First, a quad-helix appliance was applied to the mandibular dentition to correct the scissors bite in the bilateral premolar region. Later, a preadjusted edgewise appliance was applied to the maxillary and mandibular teeth. After 3 days, a mandibular distraction osteogenesis was performed. During and after the distraction, the open bite between the upper and lower dental arches was corrected using up and down elastics. The total treatment time with the edgewise appliance was 14 months. A skeletal Class I apical base relationship, good facial profile, and optimum intercuspation of the teeth were achieved with the treatment. The jaw-movement pattern on the frontal view did not change during gum chewing. However, the maximum gap without pain increased. The electromyographic (EMG) activity of the masseter and anterior temporalis muscles, and maximum occlusal force increased. The present case report suggests that an orthodontic treatment combined with mandibular distraction osteogenesis in a patient with mandibular retrusion in the late growth period might be effective for improving stomatognathic function.     

DAMON技术及MBT技术对安氏Ⅱ^1拔牙病例牙弓宽度影响的研究

目的：采用Damon-Ⅲ自锁托槽矫治技术和MBT矫治技术拔除四个第一双尖牙矫治治疗安氏Ⅱ^1错患者,研究治疗前后的牙弓宽度变化。方法：选择20例Damon-Ⅲ自锁托槽矫治技术及20例MBT矫治技术治疗安氏Ⅱ类1分类患者,均采用减数四颗第一双尖牙治疗方案,未额外使用增强支抗装置,治疗前后取寄存模型并进行测量。结果：患者经Damon矫治技术及MBT技术治疗后,均获得良好的咬合关系,Damon组治疗后上尖牙间宽度增大2.24 mm,下尖牙宽度增大1.02 mm,没有统计学意义;上双尖牙宽度减小1.57 mm,下双尖牙宽度减小1.86mm;上磨牙宽度减小1.83 mm,下磨牙宽度减小2.69 mm;MBT组治疗后上尖牙间宽度增大1.72 mm,下尖牙宽度增大1.21 mm;上双尖牙宽度减小1.03 mm,下双尖牙宽度减小1.65 mm;上磨牙宽度减小1.51 mm,下磨牙宽度减小2.37 mm;两组样本对比,上颌尖牙及双尖牙宽度变化有统计学意义。结论：Damon-Ⅲ自锁托槽矫治技术与MBT技术均可快速高效治疗安氏Ⅱ类1分类错[牙合],与MBT技术相比较,Damon-Ⅲ自锁托槽矫治技术在拔牙病例中并没有表现出明显的扩大牙宽度     

正畸治疗中磨牙的拔除和保留（四十九）—不拔牙或减数前磨牙矫治后第三磨牙萌出间隙调查

目的：通过对不拔牙矫治或减数前磨牙矫治后第三磨牙萌出间隙的调查,探讨在正畸患者中保留28颗牙齿的可行性。方法：297个样本均来自深圳市儿童医院口腔正畸科,男132例,女165例,其中18岁以下组（少年组）201例,18岁以上组（成人组）96例。均采用了不拔牙矫治或减数前磨牙矫治。测量矫治结束后口腔全景片上第二磨牙远中磨牙后间隙量及第三磨牙牙冠近远中宽度。结果：不拔牙矫治组较减数前磨牙矫治组第三磨牙萌出尚欠间隙量大,上颌的萌出尚欠间隙量较下颌小,少年组的萌出尚欠间隙量较成人组大,差异均具有显著性;在成人组中,有70％的患者可通过不拔牙或减数一组磨牙矫治获得保留28个牙齿的目的。结论：减数前磨牙在统计学上并不能完全解决第三磨牙萌出间隙的问题,通过减数一组磨牙实现保留28个牙齿的目的对大多数正畸患者是可行的,它是大概率事件,科学合理。     

Anomalous mandibular premolars: a mandibular first premolar with three roots and a mandibular second premolar with a C‐shaped canal system

Aim To describe unusual variations in the root morphology and root canal systems of mandibular first and second premolar teeth extracted for orthodontic reasons. Summary Normally mandibular first and second premolar teeth have single roots with single canals. A 15‐year‐old patient presented for orthodontic treatment and two mandibular premolar teeth were examined post‐extraction. The mandibular first premolar exhibited three distinct, separate roots and the mandibular second premolar exhibited a C‐shaped root canal system. The coronal morphology of each of the mandibular premolars revealed dimensions and anatomy within normal limits. The incidence of a three‐rooted mandibular first premolar is approximately 0.2%. Key learning points ? Thorough clinical and radiographic interpretation is important in recognizing anomalous root and root canal systems. ? The most common forms of root and canal systems and its aberrations must be understood to realize variations from normal do occur. ? Successful root canal treatment requires an accurate diagnosis of the root canal system using all available aids. ? Value of microcomputed tomography in the study of anatomy ex vivo and cone‐beam tomography in clinical endodontics of complex premolar cases is increasing.     

下颌第一磨牙缺失两基牙双端固定桥修复的生物力学分析

目的：研究下颌第一磨牙缺失两基牙双端固定桥修复的应力分布。方法：采用CT扫描获取健康成人上、下颌牙及其支持组织二维图像,通过计算机重建技术获得右下颌第一磨牙缺失后的双端固定桥桥体颊舌径分别为正常时的100%、90%、66.7%和50%与右下颌双端固定桥桥体及右下颌第二磨牙颊舌径均分别为正常时的90%、66.7%和50%的7个三维有限元模型,在相同垂直载荷和斜向载荷下分析了基牙牙槽骨高度及桥体大小对固定桥应力分布的影响。结果：当双端固定桥桥体颊舌径分别为正常大小的66.7%和50%时,固定桥两基牙中的第二前磨牙在垂直向加载时均出现明显应力集中;当下颌第二磨牙牙槽骨吸收程度等于及大于35%时,下颌第二前磨牙在其垂直向加载与斜向加载时均出现明显的应力集中,下颌第二磨牙在其垂直向加载时出现明显的应力集中。结论：固定桥受载的Von Mises最大应力集中于连接体表面。对于下颌567双端固定桥,当桥体变窄,颊舌径小于正常大小的66.7%时,有可能会对基牙中的第二前磨牙造成损害。当下颌第二磨牙牙槽骨吸收程度等于及大于35%时,可能对双基牙都造成损害,并可能促使并加速牙槽骨的进一步破坏吸收。     

Lower premolar extraction/removable plastic Herbst treatment for mandibular retrognathia

The patient was a 12-year-old girl with a Class I malocclusion characterized by maxillary arch width constriction, dental crowding, and mandibular retrognathia. Treatment goals related to the chief compliant were anterior mandibular repositioning, maxillary arch expansion, and dental alignment. Because the preexisting overjet was minimal and prevented adequate anterior repositioning of the mandible, lower first premolar extraction was recommended to increase the overjet and allow greater anterior repositioning. Treatment was divided into four stages: (1) extraction of mandibular first premolar teeth, alignment, space closure, and an increase in the overjet, (2) anterior mandibular repositioning with a removable plastic Herbst appliance, (3) arch alignment and detailing of the occlusion with full fixed appliances and a tooth positioner, and (4) retainers. At the end of treatment, the patient had an acceptable dental alignment with a Class III molar relationship and an improvement in facial appearance.     

成年人第一磨牙拔牙间隙变化的临床研究

目的观察拔牙方法对第一磨牙拔牙间隙变化的影响,分析拔牙间隙变化的原因和预防办法。方法选择44例需拔除第一磨牙的患者作为研究对象,分成3组,A组17例,拔牙后不作特殊处理。B组15例,对患牙近、远中邻牙调牙合后再拔牙。C组12例,拔牙后戴用可摘过度性义齿。分别测量各组患者拔牙后30 min、3个月时拔牙间隙的近、远中方向最小径,比较分析各组间拔牙间隙变化的情况。结果拔牙后30 min与拔牙后3个月比较,A组拔牙间隙有显著性减小(P<0.001)。B组和C组拔牙间隙都无显著性改变(P>0.05)。结论拔牙后3个月内,调牙合和过渡性义齿修复均可阻止第一磨牙拔牙间隙的减小,有利于维持拔牙后牙列稳定。     

正畸治疗中磨牙的拔除和保留（四十一）——减数磨牙替代常规减数前磨牙矫治的可行性研究

目的：探讨减数磨牙替代常规减数前磨牙矫治的可行性。方法：60例减数磨牙矫治病例再评价,按传统的设计认定42例可归于减数前磨牙模式,占70％。其中男12例,女30例;年龄15～40岁,平均26岁;安氏Ⅲ类18例、安氏Ⅱ类11例、安氏Ⅰ类13例。采用直丝弓矫治器矫治。矫治方法均采用颌间分段分次先Ⅲ类后Ⅱ类牵引进行矫治。结果：矫治期最短7个月,最长28个月,平均18个月。全部病例均获得理想的侧貌改变。前牙覆[牙合]覆盖正常,建立尖牙、磨牙的中性关系和良好的尖窝锁结关系。结论：设计减数磨牙矫治并保全28个牙齿的治疗理念对于解决牙弓后段存在的问题及避免减数前磨牙的弊端优势显著。