根尖定位片定量观测推磨牙远移后牙根吸收

目的:评价口外弓推磨牙远移对磨牙牙根吸收的影响。方法:选取使用口外弓推磨牙的病例15例。使用定位装置拍摄术前术后根尖片,测量牙根吸收量,通过头影测量描记图测量磨牙远移距离。对15例样本治疗前后牙根长度做配对t检验,并对磨牙远移距离和根吸收百分比做相关分析。结果:口外弓推磨牙远移后,磨牙近远中根治疗前后牙根长度的比较均有统计学意义(P<0.01),移动距离与根吸收程度呈正相关(近远中根的相关系数分别为r近=0.927,r远=0.924)。结论:口外弓推磨牙远移会造成牙根吸收,但吸收量较微小,在临床可以接受的范围内。牙齿移动距离是影响牙根吸收的重要因素之一。     

口外弓联合滑动杆与单纯口外弓远移6│6的比较研究

目的　研究口外弓结合滑动杆推上颌第一磨牙远移矫治安氏Ⅱ类错牙合畸形磨牙远移的变化量。方法　 16例患者进行口外弓结合滑动杆与单纯口外弓推上颌第一磨牙远移的同体对照性研究 ,平均治疗 96 .37天 ,通过模型分析确定磨牙的移动量和扭转量。结果　口外弓结合滑动杆治疗侧磨牙均达安氏Ⅰ类关系 ,磨牙远移 3.0 0mm± 1.18mm ,而单纯口外弓治疗侧磨牙远移 0 .84mm± 0 .6 8mm(P <0 .0 1)。结论　口外弓结合滑动杆加速了磨牙远移的速度 ,同时兼有部分下颌磨牙的近中移动 ,加快了纠正磨牙安氏Ⅱ类牙合关系。     

口外弓颈牵引推磨牙远移的X线头影测量分析

目的：比较口外弓颈牵引推磨牙远移治疗前后的颅面、牙齿的角度变化。方法：调取2002～2005年间完成正畸治疗病例18例作回顾性研究,均为安氏Ⅱ类错低角或均角病例,应用口外弓颈牵引推磨牙远移＋方丝弓矫治技术不拔牙矫治。对治疗前后X线头影测量数据做统计学分析。结果：SNA平均减小1.5°,SNB平均增加0.8°,FMA平均增加1.2°,GoGn-SN平均增加2.2°,治疗前后比较有显著性差异（P〈0.05）。结论：口外弓颈牵引推磨牙远移能有效改善颌骨侧貌,改善低角状况,促使下颌骨顺时针方向旋转。     

摆式矫治器与口外弓远中移动磨牙的疗效比较

目的:比较摆式矫治器与口外弓头帽牵引2种方法推磨牙远中移动的临床疗效。方法:选取牙源性安氏II类错牙合30例,按照配对实验设计的原理分为2组,分别使用摆式矫治器(P组)和口外弓头帽牵引(F组)进行不拔牙矫治。矫治前后拍摄头颅侧位片,采用Pancherz分析法进行X线头影测量分析,比较2组患者治疗前后牙颌结构的变化。采用SPSS11.0统计学软件进行配对t检验,α取0.05。结果:推磨牙远中移动的治疗时间:P组为(20.6±4.0)周,F组为(26.0±3.6)周,两者具有显著性差异P<0.01;矫治前后,P组磨牙远中移动为(-3.1±0.53)mm,F组为(-2.2±0.82)mm,两者具有显著性差异P<0.01。矫治前后,P组上颌切牙唇向移位(0.8±0.78)mm,F组上颌切牙腭向移位(-1.0±0.88)mm,两者具有显著性差异P<0.01。结论:摆式矫治器能更快速、有效地推动上颌磨牙远中移动,但需要加强对上颌前牙的支抗控制。     

口外弓单侧推磨牙向远中矫治安氏II类亚类错[牙合]临床报告

目的：探讨采用口外弓单侧推磨牙向远中矫治安氏II类亚类错[牙合]的临床效果。方法：选择恒牙列早期安氏II类亚类错[牙合]病例15例。年龄9一12岁,上颌第二磨牙尚未萌出,头影测量大致正常。取成品对称口外弓,在II类磨牙关系一侧,在口外弓的内弓套入螺旋推簧,施加200g力推磨牙远移。I类咬合关系一侧,将内弓弯成U形,起到平衡作用。为防止磨牙移动,整排牙列连续结扎。结果：推磨牙远移的时间4—7个月,平均5．5个月。磨牙远移距离3．5mm-6．0mm,平均远移4．4mm（UP0．8mm／每月）。磨牙远移结束后,II类磨牙关系改变成I类咬合关系,原来I类关系侧基本不变。磨牙远移到位后,再装配直丝弓矫治器完成矫治。结论：口外弓配合螺簧单侧推磨牙向远中,可顺利完成对安氏II类亚类错[牙合]的矫治,疗效满意。     

改良Nance弓推磨牙远中移动临床研究

推磨牙往远中移动在临床上有很多方法对于轻度前突性深覆盖及中度的牙列拥挤患者采用远移磨牙可避免拔牙改变类磨牙关系减少患者痛苦传统的推磨牙向后多用口外弓装置但这需要患者配合较麻烦利用一种口内装置即改良Nance弓它无需患者的配合就能完成磨牙的远中移动观察25例...     

种植体支抗及口外弓推磨牙向后的临床效果比较

目的观察种植体支抗推磨牙向后的临床效果并与口外弓推磨牙进行比较。方法选择恒牙初期牙列轻中度拥挤患儿16例,男5例,女11例,年龄8~11岁,随机分成A、B2组,A组采用种植体支抗,植入位置在两前磨牙间或第二前磨牙与磨牙之间根方,4周后加力;B组用头帽口外弓,4周后力值恒定为2.94~3.92N。结果B组有1例患儿因不合作,治疗7个月后停止口外弓改为拔牙矫治,其余均在治疗10个月后基本达预期效果;A组患者在治疗后3~6个月均达预期效果,且下牙轴较治疗前直立,ANB角改变,面型更和谐。结论2组均有不同程度的矫形变化;采用种植体支抗推磨牙组临床疗效、各项指标均好于口外弓组,头影测量分析差别无显著性,但种植体支抗组不依赖于患者配合,疗效迅速。     

钟摆矫治器联合颊侧推簧远移磨牙的疗效分析

目的：评价钟摆矫治器联合颊侧推簧远移磨牙的疗效.方法：选择40例牙性安氏Ⅱ类错（牙合）畸形的患者,随机均分为两组：钟摆矫治器联合颊侧推簧远移磨牙组（组1）和头帽口外弓远移磨牙组（组2）,在治疗开始前（T0）和远移磨牙完成时（T1）分别拍摄侧位头影定位片进行头影测量,t检验分析组内和组间的差异.结果：组1和组2远移磨牙的平均距离分别是（4.48±1.63） mm、（2.68±1.71） mm;组1和组2磨牙远中倾斜的平均角度分别是5.46°±3.23°、1.02°±2.16°;组1上颌中切牙未发生明显的唇倾和唇向移位,而组2上颌中切牙发生了较为明显的腭侧移位.结论：钟摆矫治器联合颊侧推簧远移磨牙可有效防止前牙支抗的丧失、控制磨牙的近中颊侧旋转.     

下颌第三磨牙长距离近中移动后牙根吸收的研究

目的 通过对拔除下颌第一磨牙病例的回顾性研究,探讨第三磨牙在长距离近中移动后其牙根的吸收情况,同时比较第三磨牙牙根发育完成与否对牙根吸收的影响。方法 回顾性分析32例拔除下颌第一磨牙的病例,共41颗下颌第三磨牙。根据第三磨牙牙根的发育情况,分为A组(发育完成组)和B组(未发育完成组),采用直接数字化全景片测量矫治前后下颌第三磨牙牙根的长度,研究不同发育阶段的第三磨牙在长距离近中移动后其牙根的变化。结果 A组第三磨牙在长距离近中移动后,近远中牙根分别吸收(0.07±0.66) mm、(0.09±0.62) mm,差异没有统计学意义(P>0.05);B组第三磨牙牙根继续发育,矫治结束后长度增加,差异具有统计学意义(P<0.05);B组较A组下颌磨牙近中移动距离大,差异具有统计学意义(P<0.05)。矫治结束后A组、B组近中牙根长度差异没有统计学意义(P>0.05),但远中牙根B组较A组长,差异具有统计学意义(P<0.05)。结论 下颌第三磨牙长距离近中移动后,其牙根的吸收量较小,不具备临床意义,牙根发育情况对远中牙根存在一定影响,提示临床中磨牙缺失后要在第三磨...     

Peripheral inflammatory root resorption

External resorptions associated with inflammation in marginal tissues are many times misdiagnosed and confused with caries and internal resorptions. A lack of uniformity in nomenclature has added to the confusion. This paper reviews the literature and presents cases to illustrate a rational approach to diagnosis and treatment. A new name is suggested to better reflect the features of this type of root resorption: peripheral inflammatory root resorption.     

Morphologic criteria for root canal treatment of primary molars undergoing resorption

Abstract The endodontic anatomy of primary molars is difficult to predict because of the balance of resorption and hard tissue deposition. In particular, the resorption causes perforating lacunae across the wall of the root, even at the furcation level, and modifies shape, dimension and position of endodontic apex. The phenomenon can be so deep as to compromise endodontic therapy. The first aim of the study was to verify if reliable criteria can be found for treatability in primaiy molars undergoing resorption, i.e. if it is possible to predict if perforating lacunae are present or not. The second aim of the study was to verify if other informations needed for endodontic treatment, as shape, dimension and location of the apex, and curvature of the root canal can be predicted. For the study, 80 extracted primary molars, 75 of which pulpally involved by caries, were selected. The treatability was evaluated in term of root length, root shape, dimension and shape of endododntic apex, age of the patient and Xray index of resorption. The association between variables was performed by multiple correspondence analysis. The results suggested that root length was the most reliable criterion of the integrity of the root. The borderline of treatability was at the length of 4 mm. The position of endodontic apex related to anatomical apex, and the lingual related to the buccal root length were analyzed by linear regression analysis. The canal length was often similar to the root length (i.e. the endo and anatomical apices were very close) in lower and upper molars. However, in lower molars, if two or more canals were present in the same root, a discrepancy was observed between buccal and lingual root length. This finding was constant in first lower molars. In addition regression analysis provided a linear function between the lengths of the buccal and lingual side of the same root in lower molars. Its coefficient b was 0.73.     

Risk factors for root resorption of second molars associated with impacted mandibular third molars

External root resorption (ERR) affecting mandibular second molars (M2) may occur when the adjacent third molar (M3) is impacted in close proximity. This retrospective cohort study aimed to assess the presence, severity, and location of ERR on M2 due to M3 using cone beam computed tomography (CBCT) scans and to identify associated factors. The angle between the axis of M2 and M3 was measured. ERR on M2 was classified as absent, slight, moderate, or severe. The location of contact between M3 and M2, the size of the dental follicle, and patient demographic characteristics were recorded. A total of 433 patients with 640 M3 were included. A male predilection was found with regard to ERR (P = 0.0004). ERR was identified on 31.9% of M2 and was slight in 30.2%, moderate in 1.4%, and severe in 0.3% of cases. The presence of ERR was associated with direct contact between M2 and M3 (P < 0.0001), the angle between M2 and M3 (P < 0.0001), the inclination of M3 (P = 0.001), and the location of contact (P = 0.0005). This study showed ERR to be a frequent finding. ERR is associated with a mesioangular position of M3 in more than one third of cases, and a proximity ≤0.5 mm between M2 and M3 favours ERR.     

Multiple idiopathic cervical root resorption involving all permanent teeth

Multiple idiopathic external cervical root resorption is a rare condition with numerous predisposing factors that have not yet been clearly elucidated. In addition, its diagnosis and treatment pose challenges for clinicians, and thus, the extraction of the involved teeth is commonly performed. Here, we report a 29‐year‐old pregnant woman with no contributory medical or family/social history who experienced cervical root resorption that progressed aggressively and involved all permanent teeth. This case is unique owing to the involvement of all teeth. Reports of multiple idiopathic external cervical root resorption are rare in the literature, and the pathogenesis of the condition is poorly understood. This report aims to add an additional case to the existing literature, analyse the underlying mechanisms and provide clinicians with some guidance in diagnosing cervical root resorption.     

Influence of steroid drugs on orthodontically induced root resorption

OBJECTIVES: To investigate the effect of acute and chronic corticosteroid treatment on orthodontically induced root resorption. DESIGN: 'Split mouth' design performing orthodontic tooth movement in 64, 6-month-old male rats divided into three groups: acute (n = 22), chronic (n = 23) and control group (n = 19). Acute and chronic group received corticosteroid treatment (8 mg/kg/day) for 3 and 7 weeks, respectively, while no pharmacological treatment was performed in the control group. Performed at the Department of Orthodontics, School of Dentistry, University of Aarhus, Aarhus, Denmark. EXPERIMENTAL VARIABLE: The upper left first molar was moved mesially for 21 days in all three groups with 25 g of force. Undecalcified histological sections were cut at the coronal and apical level. OUTCOME MEASURE: The number of intersections hitting resorption lacunae (ES), defined as a scalloped surface with or without cementoclasts, over the total number of intersections hitting the root surface (RS) were recorded and expressed as percentage. RESULTS: The acute group showed significantly more root resorption at the mesio-coronal level compared with the control and the chronic group. CONCLUSION: This could be ascribed to the lack of balance between blastic activities (inhibited by the drug) and the clastic activities (enhanced or unchanged by drug administration) occurring in the initial phase of drug administration. As a consequence, a careful monitoring of patients undergoing acute corticosteroid treatment is suggested.     

Cervical external root resorption in vital teeth

External resorptions associated with inflammation in marginal tissues present a difficult clinical situation. Many times, lesions are misdiagnosed and confused with caries and internal resorptions. As a result inappropriate treatment is often initiated. This paper provides three-dimensional representations of cervical external resorption, based on X-ray microfocus-tomographical scanning of a case, which will aid the dental practitioner in recognizing characteristic features during clinical inspection. In addition, histopathological examination reveals the cellular morphology of the adjacent tissues.     

GMD矫治器与钟摆矫治器远移上颌磨牙效果对比研究

目的：通过对GMD矫治器与钟摆矫治器的对比研究探讨该矫治器应用的可行性、优越性及其适应症.方法：对58例因上颌磨牙前移所导致的安氏Ⅱ类错[牙合]患者,分别使用GMD矫治器与钟摆矫治器进行推上颌磨牙向远中移动的非拔牙矫治,通过矫治前及磨牙远移到位后的X线头影测量及模型测量分析进行对比研究.结果：两种方法最终都实现了推磨牙远移的目的,但是GMD矫治器的磨牙移动更接近于整体移动,支抗控制也强于钟摆矫治器.结论：GMD矫治器能够有效、快速地远移磨牙,是一种新的有效远移磨牙的矫治器.     

A case of progressive external root resorption

Abstract This case report describes a radiographical, histological and histochemical study of an extracted mandibular tooth with progressive external root resorption. The cells which appeared to be responsible for the hard tissue resorption showed an intense acid phosphatase activity, similar to that of bone-resorbing cells. Some aspects on the etiology and pathogenesis of resorptive process that occurred in the present case are discussed.