Treatment after inadequate immediate replantation of accidentally extracted immature mandibular premolar during primary molar extraction

During extraction of the primary mandibular right second molar in an 11‐year‐old girl, the unerupted second premolar was accidentally extracted. Clinical and radiographic examination showed that the immediately replanted immature premolar was not oriented and positioned correctly. Four hours later, treatment consisted of manual extrusion of the permanent tooth bud, rotation, and gentle repositioning into its original position. Adequate replantation was confirmed by a post‐operative radiograph. After 2 years and 4 months, clinical examination revealed normal, healthy appearance of the replanted tooth, no sensitivity to percussion, no tenderness to palpation, and a slight response to a cold pulp sensibility test. A radiograph showed completely developed root with closed apical foramen, slightly irregular root morphology and shorter root length, complete obliteration of the pulp, and no signs of periapical pathosis.     

Immediate and six-month space changes after premature loss of a primary maxillary first molar

BACKGROUND: Premature loss of primary maxillary first molars has been associated with a number of consequences (such as tipping of the first permanent molar). The aim of the authors' study was to investigate dental-arch space problems arising as a result of premature loss of a primary maxillary first molar. METHODS: This study was composed of 19 children who experienced unilateral premature loss of a primary maxillary first molar. The authors used each patient's intact contralateral arch segment as a control. The authors obtained maxillary dental study casts two or three days after the tooth was extracted, as well as six months later. RESULTS: The D + E space from the extraction side six months after removal of the tooth (mean +/- standard deviation, 15.62 +/- 1.13 millimeters) was significantly smaller than the space on the control side (16.88 +/- 1.12 mm) and the initial D + E space (16.70 +/- 0.69 mm). The authors found a significantly shorter arch length (25.47 +/- 1.58 mm) and larger intercanine width (31.29 +/- 2.49 mm) six months after the tooth was extracted compared with the initial arch length (25.66 +/- 1.64 mm) and intercanine width (30.42 +/- 2.64 mm). CONCLUSIONS: The early space changes to the maxillary arch subsequent to premature loss of a primary maxillary first molar are primarily distal drift of the primary canines toward the extraction space and palatal migration of the maxillary incisors. Although 1 mm of space was lost, which is statistically significant, this is not likely to be of sufficient clinical significance to warrant use of a space maintainer. If palatal movement appears to be needed, the dentist should consider use of a palatal arch rather than a band-and-loop maintainer. CLINICAL IMPLICATIONS: The effects of space maintainers need to be re-evaluated in cases of unilateral premature loss of a primary maxillary first molar.     

正畸治疗中磨牙的拔除和保留(十二)——拔除磨牙与拔除前磨牙矫治牙根吸收的对比研究

目的：通过对磨牙拔除病例与前磨牙拔除病例的牙根吸收情况的对比,探讨关闭磨牙间隙是否加重牙根吸收。方法：将矫治前后下颌第二磨牙的冠根比作为判断牙根吸收程度的指标。其中拔除下颌第一磨牙病例的牙根数为72个,拔除下颌第一前磨牙病例的牙根数为74个。将测量值进行配对t检验。结果：第一磨牙拔除病例与第一前磨牙拔除病例相比,虽然矫治后下颌第二磨牙牙根吸收的程度较大,但两组间比较并无显著性差异。结论：采用拔除第一磨牙后的第二磨牙近中平移技术,并不加重矫治后磨牙牙根的吸收。     

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。     

Long-term follow-up of delayed development of maxillary right second premolar with inversely positioned corresponding primary molar

Impaction is defined as a condition in which a tooth fails to erupt within a normal range of functional position. The condition is generally found in permanent teeth, while impaction of primary teeth is considered to be uncommon. We previously presented a rare case of delayed development of a maxillary right second premolar with an inversely positioned corresponding primary molar identified in a girl aged 10 years and 4 months. In the present report of the same patient, we show transitional changes in location and developmental stage of the affected permanent tooth and impacted primary tooth noted during periodical examinations over a 5.5 year period. At 13 years and 2 months, the root of the permanent tooth began to develop, after which the root extended to half of the entire length at 15 years and 3 months. At the most recent examination conducted at 15 years and 9 months, the permanent successor had emerged into the oral cavity and the impacted primary molar maintained a similar position close to the inferior wall of the maxillary sinus without any symptoms. Throughout the observation period, the dental age of the maxillary right second premolar was calculated to be approximately 3 to 4 years behind those of the other second premolars. Our findings in the present case led us to consider that careful observation of the developmental stage of an unerupted permanent tooth is important, while no intervention is required before confirming tooth development as the patient grows, even if the dental age of the corresponding tooth is much later than the ages of other teeth.     

拔除第一前磨牙对第三磨牙倾角的影响

目的研究正畸治疗中拔除第一前磨牙进行矫治和非拔牙矫治对第二磨牙和第三磨牙倾角的影响。方法选择56例上下颌第三磨牙均存在的青少年正畸患者,按拔牙与否分为拔牙组（30例,拔除4颗第一前磨牙）和非拔牙组（26例）,通过术前术后曲面断层片来测量患者上下颌第三磨牙长轴和平面的交角,第二磨牙与平面的交角以及第二、第三磨牙长轴的交角,并进行统计学分析。结果拔牙与非拔牙组矫治前后第三磨牙倾角均有不同程度的改善。与非拔牙组相比,拔牙组上下颌第三磨牙长轴与平面交角的变化量更大,2组间年平均变化量的差异有统计学意义（P<0.05）;2组矫治前后上下颌第二、第三磨牙长轴交角的变化无统计学差异,但其年平均变化量在2组间则有统计学差异（P<0.05）。2组间上颌第二磨牙与平面交角的年平均变化量无统计学差异（P>0.05）,而下颌第二磨牙与平面交角的年平均变化量则有统计学差异（P<0.05）。结论拔除第一前磨牙进行正畸治疗有利于第三磨牙倾角的改善,对第三磨牙萌出有积极意义。     

拔除第二恒磨牙后第三磨牙自行迁移的临床研究

目的 :探讨第二恒磨牙拔除后第三磨牙自行迁移在水平方向、垂直方向距离变化以及近中倾斜角的改变。方法 :将 2 6例患者分为实验组和对照组 ,实验组拔除第二恒磨牙的患者 15例 ,对照组未拔第二恒磨牙的患者 11例。 2组均拍摄侧位X线头影测量片 ,治疗前和治疗 9个月后测量第三磨牙在水平方向、垂直方向移动距离和近中倾斜度的变化并进行比较。结果 :实验组第三磨牙较对照组在水平方向 ( 7.0 8mm ,2 .0 9mm)移动较快 ,有显著差异 ;在垂直方向 ( 5 .75mm ,1.96mm)移动较快 ,有显著差异 ;其近中倾斜角变化 ( 11.2° ,3 .97°)也有显著意义。结论 :拔除第二恒磨牙加速了第三磨牙的萌出 ,减少了第三磨牙的阻生 ,并使第三磨牙尽快直立 ,并向近中迁移。     

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。     

正畸治疗中磨牙的拔除和保留(三十四)——对称拔除双颌非同名磨牙的矫治设计

目的：探讨对称性拔除双颌非同名磨牙矫治各类错[牙合]的效果。方法： 选取设计拔除磨牙进行矫治的错[牙合]畸形病例92例,其中设计对称性拔除双颌非同名磨牙病例17例（男性6例,女性11例）。全部病例采用直丝弓矫治技术矫治。结果：矫治结束时全部病例均达到尖牙和磨牙的中性关系,前牙覆[牙合]覆盖正常,牙根基本平行,软组织侧貌协调。结论：对称性拔除双颌非同名磨牙矫治错[牙合]畸形亦可获得良好的矫治效果。     

正畸治疗中磨牙的拔除和保留（五十一）——关闭第一或第二磨牙拔牙间隙后相邻后牙根平行度的研究

目的：对临床中设计减数第一或第二磨牙矫治的病例进行调查,观察关闭间隙后相邻后牙根平行度情况。方法：选择病例41例,男10例,女31例,初诊年龄平均21岁,矫治结束时年龄平均23岁,所有病例均采用直丝弓矫治器矫治。分别对矫治前（T1）、矫治结束（T2）的拔牙间隙相邻后牙根平行度测量值进行分析。结果：减数第一磨牙矫治病例除下颌第二磨牙与第二前磨牙牙轴夹角及下颌第三磨牙与第二前磨牙牙轴夹角差别无显著性以外,其余测量项目均有显著性差异;减数第二磨牙矫治病例除上颌第一磨牙牙轴倾斜度及下颌第三磨牙与第一磨牙牙轴夹角无显著性差别外,其余测量项目均有显著性差异。说明第一或第二磨牙拔牙间隙关闭后上颌后牙不易达到根平行,下颌后牙容易达到根平行。结论：减数第一或第二磨牙的矫治方法可以实现下颌拔牙间隙相邻后牙的根平行,但对于上颌拔牙间隙两侧的牙齿很难实现根平行。原因主要是上颌后牙的牙根与上颌窦底的位置关系密切,对上颌后牙的牙根移动产生了阻碍。     

下颌前磨牙拔除对第三磨牙萌出的影响

目的:探讨安氏I类中度拥挤病例拔除下颌第一或第二前磨牙后对第三磨牙的不同影响。方法:将28例患者分为拔除第二前磨牙组12例,拔除第一前磨牙组16例,治疗中均运用改良片段弓技术。2组均在治疗前、后拍摄X线头影侧位定位片,以测量下颌第三磨牙萌出过程中在水平、垂直距离的变化及其近中倾斜角、与第二磨牙交角的变化,采用SAS6.12统计软件包对数据进行t检验。结果:拔除第二前磨牙组,第三磨牙在水平方向、垂直方向移动较拔除第一前磨牙组多,分别为(2.95±2.55)mm(P<0.01)和(4.58±1.85)mm(P<0.01);其近中倾斜角变化-10.12°±8.27°(P<0.05)、与第二磨牙交角的变化-15.58°±9.65°(P<0.001)也有显著差异。结论:对安氏I类中度拥挤病例,拔除下颌第二前磨牙较拔除第一前磨牙可为下颌第三磨牙提供更多的有效萌出间隙,并使第三磨牙牙冠发生有效旋转。     

正畸治疗中磨牙的拔除和保留（四十二）——下颌第三磨牙获得性间隙对其生长发育的意义

目的：揭示第三磨牙在牙根发育完成前受正畸治疗干预而获得充足的发育空间，其牙根生长发育的特征及意义。方法：随访21例第三磨牙牙根未发育完成前接受拔除第一或第二磨牙进行正畸治疗的青少年，调查其下颌第三磨牙牙根发育完成后的牙根融合率、根分又程度及根长，并与下颌第二磨牙对应数值进行比较。结果：下颌第三磨牙在牙根生长完成发育前获得充足的生长空间后其牙根的分叉率、分叉程度均高于下颌第二磨牙，其牙根长度与下颌第二磨牙相仿。结论：下颌第三磨牙牙根融合可能是因空间不足受挤压所致，利用第三磨牙代替第二磨牙的正畸治疗应尽量选择在第三磨牙牙根未发育完成前进行。     

正畸治疗中磨牙的拔除和保留（四十八）——减数前磨牙与减数磨牙对相同错[牙合]矫治结果的影响

目的：探讨减数前磨牙与减数磨牙对相同错[牙合]矫治结果的影响。方法：选取2个同年龄,错[牙合]类型相近的病例,以典型病例形式分析减数前磨牙与减数磨牙设计模式对于矫治结果的区别和意义。结果：病例1采用减数第一前磨牙设计,最终只能保留24颗功能牙,第三磨牙阻生;病例2采用减数磨牙设计,最终保留28颗牙齿的牙列。结论：减数磨牙矫治适用于多数常规减数前磨牙病例,避免了减数前磨牙可能造成的第三磨牙阻生问题,同时又可以解决牙弓前、中、后段的问题。     

正畸治疗中磨牙的拔除和保留(十一)——拔除第二磨牙与拔除第一前磨牙后第三磨牙牙胚位置的对比研究

目的：比较正畸治疗中拔除第二磨牙与拔除第一前磨牙后第三磨牙牙胚位置的不同改变。方法：选择拔除第二磨牙患者18例及拔除第一前磨牙患者20例,对两组治疗前后X线头颅侧位片进行测量分析。观察矫治前后第三磨牙在垂直方向、水平方向及倾斜角度的改变,比较两组间的差异。结果：两组病例上、下颌第三磨牙垂直位置的改变有显著性差异,拔除第二磨牙组比拔除第一前磨牙组第三磨牙向胎方移动快。水平距离的改变两组之间无差异。拔除第二磨牙组的下颌第三磨牙在矫治后明显竖直,与对照组之间存在显著性差异;矫治后两组上颌第三磨牙的角度均有较大改善,但两组之间的改变无差异。结论：拔除第二磨牙比拔除第一前磨牙加速了第三磨牙向骀方的移动,有利于下颌第三磨牙的竖直,为其以后的萌出创造了有利条件,减少了第三磨牙阻生的可能性。     

根管消毒药物缓解乳磨牙根尖周炎临床症状的疗效分析

目的：对比四种临床常用的根管消毒药物缓解乳磨牙根尖周炎临床症状的效果。方法 选择根尖周炎乳磨牙160颗,随机分为四组,每组40颗,根管预备超声荡洗后,A组封入抗生素糊剂,B组封入Vitapex糊剂,C组封入氢氧化钙糊剂,D组封入樟脑酚棉球,10 d后复诊,对四种根管消毒药物缓解乳牙根尖周炎临床症状的效果进行评价。结果 在10d后脓肿消除方面抗生素糊剂组效果优于其他三组（P=0.005）,Vitapex组与氢氧化钙组效果,均优于樟脑酚组（P＜0.05）。术后24h内疼痛的发生率抗生素糊剂组术后24 h内疼痛发生率低于Vitapex组（P=0.014）和氢氧化钙组（P=0.045）。10 d后疼痛的比例各组之间无统计学差异。结论 抗生素糊剂能够有效缓解乳牙根尖周炎的临床症状。     

正畸拔除下颌前磨牙对第三磨牙萌出影响的测量研究

目的:评价正畸拔除下颌前磨牙对下颌第三磨牙萌出角度和间隙的影响.方法:选取23 例正畸非拔牙矫治病例(男性12 例,女性11 例,平均年龄13.5 岁),23 例拔除下颌第一前磨牙矫治病例(男性12 例,女性11 例,平均年龄13 岁),21 例拔除下颌第二前磨牙矫治病例(男性11 例,女性10 例,平均年龄14.07 岁),在治疗前和治疗后拍摄全颌曲面断层片,测量下颌第三磨牙的轴倾角度和萌出间隙,使用SPSS 17.0软件对3 组病例的数据进行配对t检验.结果:拔除下颌第一前磨牙组患者RS,LS,Rratio,Lratio在治疗后显著增大(P<0.01);拔除下颌第二前磨牙组患者RM3,LM3等指标在治疗后增大(P<0.05),RS,LS,Rratio,Lratio等指标在治疗后显著增大(P<0.01).结论:正畸拔除下颌前磨牙较非拔牙矫治可以增加下颌第三磨牙的萌出间隙;拔除下颌第二前磨牙可以改善第三磨牙的萌出角度.     

Autotransplantation of a maxillary third molar to replace a maxillary premolar with vertical root fracture

Aim To report the successful autotransplantation of a fully developed third molar that required nonsurgical and surgical interventions for tooth adaptation. Summary This case report describes the autotransplantation of a third molar with complete root development after the loss of a fractured premolar in a 47-year-old male. To allow better adaptation of the donor tooth, the buccal roots of the third molar were removed using a diamond bur and the canal entrances were filled. Recall examination 6 years after completion of root-canal treatment showed normal periodontal healing with absence of infection, ankylosis or progressive resorption. The transplantation of a third molar is seen as a promising method to replace a lost permanent tooth, and to restore aesthetics and function. Key learning points

• • Autotransplantation is a viable option for the treatment of a missing tooth or for replacement of traumatized tooth when there is a donor tooth available.
• • Fully developed third molars are potentially reliable candidates in the absence of other suitable donor teeth.

     

Displacement of maxillary right second premolar caused by gutta percha filling in corresponding primary molar

Background

For pulp therapy in primary teeth, commonly performed in daily clinical practice, calcium hydroxide paste is widely used as a root canal filling material and typically resorbed by the permanent successor upon its emergence into the oral cavity.

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目的    评价正畸拔除第二前磨牙对第三磨牙萌出角度和萌出间隙的影响。方法    选择2007年1月至2010年7月在济南市口腔医院正畸科行直丝弓正畸治疗的41例安氏Ⅰ类错牙合青少年患者,所有患者第二前磨牙及第二磨牙完全萌出,第三磨牙牙冠已形成但均未萌出。按治疗方法分为拔牙组（21例,均拔除4个第二前磨牙）和非拔牙组（20例）。在治疗前后分别拍摄全口曲面断层片,测量第三磨牙的倾斜角度和萌出间隙。结果    治疗前后上、下颌第三磨牙萌出间隙的增加值拔牙组大于非拔牙组,差异有统计学意义（P < 0.001）。上颌第三磨牙萌出角度的增加值拔牙组大于非拔牙组,差异有统计学意义（P < 0.05）,而下颌第三磨牙萌出角度的增加值两组间差异无统计学意义（P > 0.05）。结论    正畸拔除第二前磨牙可以增加上、下颌第三磨牙的萌出间隙,并使上颌第三磨牙萌出角度更加直立。