控根辅弓对上颌切牙转矩疗效的临床研究

目的：探讨控根辅弓对直丝弓矫治器患者的上颌切牙转矩效果。方法：选择22例安氏Ⅱ1拔牙矫治的患者,采用直丝弓矫治器矫治,在精细调整阶段配合控根辅弓对过度直立或内倾的上颌切牙进行正转矩。按主弓丝不同分为2组,14例主弓丝为0．46 mm ×0．64 mm 的不锈钢方丝,8例主弓丝为0．46 mm 的不锈钢圆丝。对22例上颌切牙转矩前后的 X 线头影测量结果采用 t 检验进行统计分析。结果：22例上颌切牙转矩后的 X 线头影测量结果显示,1-SN、UIa-NA 值增加（P ＜0．01）,控根辅弓对上切牙的正转矩效果明显;转矩的时间,主弓丝为圆丝上颌切牙转矩快于主弓丝为方丝,P ＜0．05。结论：在直丝弓矫治的精细调整阶段,配合前牙控根辅弓,是对内收后过度直立或舌倾的上颌切牙实现转矩的简单、有效的方法。     

平面导板对正畸治疗中牙根吸收影响的临床研究

目的：探讨平面导板配合直丝弓矫治对牙根吸收的影响。方法：随机选择66例经过直丝弓矫治的成年非拔牙患者，其中33例配合使用平面导板治疗。治疗前后拍全口曲面断层片，分别测量2组治疗前后下颌4个切牙的牙根吸收等级，并经过计算机进行X^2检验。结果：2组正畸治疗后均有明显的牙根吸收，治疗前后牙根吸收等级有显著性差异（P〈0．01）。治疗后2组间牙根吸收等级也有显著性差异（P〈0．01）。结论：直丝弓配合平面导板矫治组较单独使用直丝弓矫治的牙根吸收更严重。     

方丝弓矫治技术方形弓丝使用中的一些问题

方丝弓矫治技术方形弓丝使用中的一些问题曾祥龙在方形（矩形）弓丝上弯制第三序列弯曲产生转矩力，对切牙进行唇舌向控根，是方丝弓矫治器的独特作用＇＇＇。方形弓丝可以在第二阶段关闭前牙间隙时使用，在第三阶段治疗中更作为常规弓丝。转矩力曾一度被视为一种＂危险而...     

自锁托槽与传统托槽导致正畸牙根吸收的锥形束CT比较

目的:比较被动自锁托槽与传统直丝弓托槽造成牙根根尖外吸收量的差异,分析被动自锁托槽与牙根吸收的关系.方法:将50例患者随机分为2组,每组25例,分别应用被动自锁托槽或传统直丝弓托槽(0.022系统)进行矫治.治疗前、后拍摄锥形束CT(CBCT),测量上切牙的牙根根尖外吸收量.采用SPSS17.0软件包对2组牙根根尖外吸收量的差异进行t检验.结果:被动自锁托槽和传统直丝弓托槽治疗结束后,上颌切牙牙根吸收量无显著差异(P＞0.05).结论:被动自锁托槽和传统直丝弓托槽都会造成一定量的牙根吸收,但两者造成的牙根根尖外吸收量差异无显著性,不能认为被动自锁托槽会诱发更多的牙根吸收.     

根管充填牙在直丝弓技术矫治中根吸收观察

目的 探讨直丝弓技术治疗中根管充填牙的根吸收情况.方法 观察31例经直丝弓矫正器治疗的根管充填牙,并与对侧未经牙髓治疗同名牙进行比较.结果 矫治前后X线片测量表明,直丝弓技术治疗后根管充填牙牙根长度有减小,但与正常牙的牙根长度变化量相比差异无统计学意义(P＞0.05).结论 经完善牙髓治疗的无髓牙在直丝弓技术治疗中牙根吸收量与正常牙无差异.     

无托槽隐形矫治器和直丝弓矫治器对切牙牙根吸收的影响

目的:评估使用无托槽隐形矫治器和直丝弓矫治器的患者切牙牙根吸收情况.方法:分别选取28例使用无托槽隐形矫治器(实验组)和直丝弓矫治器(对照组)的患者,分析患者术前、术中6个月及术后的锥形束CT(CBCT)影像.通过测量各时间段的牙根长度,比较2组患者牙根吸收有无差异.对于牙根长度未见变化的患牙,通过CBCT检测其有无单纯唇腭侧和近远中骨质吸收.采用SPSS16.0软件包对数据进行统计学分析.结果:术后6个月,实验组患者47.3％的牙出现牙根吸收,显著少于对照组的68.8％ (P＜0.05).2组患者上颌中切牙牙根吸收的发生率均高于其他牙(实验组为55％,对照组为75％).矫治完成后,对照组牙根吸收的发生率上升到85.3％,而实验组上升到68.3％(P＜0.05).部分牙根长度未见减少的牙也存在局部根吸收,骨吸收最常发生在牙根的腭侧面(实验组为18％,对照组为14％).结论:与传统直丝弓矫治器相比,使用无托槽隐形矫治器的患者切牙牙根吸收程度较小.     

正畸治疗导致牙根外吸收的临床分析

目的：调查正畸治疗导致牙根外吸收的发病情况,分析其临床特征及相关因素。方法：随机选择经直丝弓矫治技术完成的病例230例,以Levander根吸收分级法对患者全颌曲面断层片进行分析,评估矫治前后中切牙至第一磨牙的根吸收情况。结果：正畸治疗后根吸收发生率明显升高,根吸收均值（root resorption after treatment,RRAT）及根吸收增加量均值（increment of root resorption,IRR）表现为上切牙最高,拔牙组高于未拔牙组,异常根形态组高于正常根形态组。结论：正畸治疗可提高根吸收发生几率,并加重根吸收程度,此可能与拔牙与否、牙位、根形态及治疗前牙根吸收程度有关。     

直丝弓矫治系统中上颌前牙单曲转矩簧的临床应用11例

目的评价在直丝弓固定矫治系统中上前牙应用成品单曲转矩簧来控制个别牙转矩的疗效。方法对直丝弓固定正畸治疗的患者11例应用单曲转矩簧共15颗牙,使用时间2⁶个月。结果所有的患者均获得了满意的转矩效果,没有患者发生牙根暴露及牙根吸收等并发症。结论在直丝弓矫治系统中配合使用单曲转矩簧控制个别牙转矩,是一种简便、经济、高效的辅助手段。     

种植支抗治疗露龈笑过程中切牙牙根吸收的CBCT检测

目的　通过CBCT技术精确测量种植支抗治疗露龈笑过程中所导致的上颌切牙牙根吸收的情况。方法　11例患者全部采用直丝弓矫治技术,在上颌两侧侧切牙和中切牙之间的牙槽骨上,各植入1枚微螺钉,每侧约0.98 N压低上前牙。当龈缘距与微笑线基本平齐时,治疗停止,进入保持阶段。治疗前后拍摄CBCT,在矢状位图像选取牙根长度最长的轴面进行长度测量。结果　所有患者露龈笑均有明显改善,平均减小(2.47±0.64)mm,切牙压入量为(2.81±0.62)mm。CBCT显示,治疗前后切牙牙根有一定程度的吸收,其中中切牙的吸收量大于侧切牙,但没有统计学意义。结论　采用种植支抗治疗露龈笑会导致上颌切牙出现牙根吸收,CBCT能够定量测量根吸收的情况。     

改良的转矩工具-精确转矩钳和精确转矩卡

方丝转矩钳(简称转矩钳)和方丝转矩卡，主要应用于方丝弓上对牙齿进行控根移动，用于第三序列弯曲的弯制，常成对使用弯制转矩，用转矩钳或转矩卡在方丝弓上做转矩，而产生转矩力。转矩力的应用主要对矫治牙作控根移动，使牙根作唇颊、舌向的移动，同时，可在拔牙矫治病例中使牙齿移动时保持牙根平行。在矫治弓丝上做转矩弯曲时，需要有两把专用的转矩钳或转矩卡。     

不同方法压低下切牙对牙根吸收影响的临床研究

目的：观察平面导板、预成镍钛摇椅弓、多用途唇弓三种方法压低下切牙对牙根尖吸收的影响。方法：102例经过直丝弓矫治的青少年非拔牙矫治深覆胎病例，分别用平面导板、预成镍钛摇椅弓、多用途唇弓三种方法压低下切牙纠正深覆殆，并在全颌曲面断层片上观察矫治前后的牙根尖吸收情况。结果：采用三种方法矫治前后的统计结果P〈0．01，矫治三种方法之间比较P〈0．01，说明三种压低下切牙的方法均会造成或加重牙根的吸收，不同的方法引起牙根吸收的程度有差异。结论：不同方法压低下切牙会引起不同程度的牙根吸收。使用平面导板压低下切牙比使用摇椅弓和多用唇弓会引起更明显的牙根吸收。     

Internal root resorption associated with inadequate caries removal and orthodontic therapy

This case report presents a case of internal root resorption originating from inadequate caries removal and orthodontic therapy in maxillary right lateral incisor in a 13-yr-old female. A preoperative, panoramic radiograph taken at the orthodontic office showed no evidence of resorption, however, the composite restoration in the coronal portion was inadequate. During 4 months of nickel titanium orthodontic wire activation, the patient suffered spontaneous pain. Periapical radiographs revealed internal root resorption in the middle third of the root. Endodontic treatment was accomplished and coronal restorations were completed with composite resin. Periodical radiograph examination as well as orthodontic treatment was continued. The tooth was clinically and radiographically healthy at the 18-month follow-up. The importance of the preoperative radiographic examination as well as radiographs during orthodontic treatment is affirmed.     

正畸治疗时间长短与牙根吸收关系的研究

目的:探讨口腔固定正畸治疗的矫治疗程长短对牙根吸收的影响。方法:选取13~19岁安氏Ⅱ类I分类患者,拔除4个第一前磨牙后,通过直丝弓矫治器进行矫治,并且在疗程中选取未采用种植体支抗干预的患者36例。按整个固定矫治疗程分为:短期组(<18个月)和长期组(>24个月);牙根形态按等级分级,计算机进行统计分析各级頻数分布变化。对两组患者治疗前后,分别在牙冠处纵向固定5 mm结扎丝拍摄锥形束CT(cone beam computed tomography ,CBCT)片,并在CBCT上描画出上颌4颗切牙的轮廓,并进行牙根长度测量。通过牙根吸收等级计算公式计算出每颗牙齿矫治后牙根实际吸收量。结果:两组病例治疗后牙根吸收均达到1~2级居多;固定矫治治疗程超过2年的长期组牙根吸收达3~4级多于短期组,其差异有统计学意义(P<0.01);牙根长度吸收长期组多于短期组,其差异有统计学意义(P<0.001)。结论:口腔固定正畸矫治疗程超过2年会加重正畸治疗中的牙根吸收,为临床治疗提供理论依据。     

Apical root resorption 6 months after initiation of fixed orthodontic appliance therapy.

INTRODUCTION: Individual predisposition might be a major reason for the observed variation in apical orthodontic root resorption. If so, resorption might be expressed during the initial stages of orthodontic therapy in patients at risk. METHODS: To explore this hypothesis, we evaluated standardized, digitized periapical radiographs made before treatment (T1) and at a mean period of 6.4 months (SD 0.9) after placement of maxillary incisor brackets (T2) in 290 patients (age range, 10.1 to 57.1 years at T1). Anamnestic and treatment parameters were recorded according to a protocol, and maxillary incisor irregularity was measured on T1 study models. RESULTS: The mean average root resorption for 4 incisors was 0.53 mm (SD 0.47), whereas the sample mean of the most severely resorbed tooth per patient was 1.18 mm (SD 0.86). A total of 4.1% of the patients had an average resorption of 1.5 mm or more, and 15.5% had at least 1 tooth with 2.0 mm or more resorption. The maximum amount of resorption was 4.4 mm. Multivariate linear regression showed that deviated root form and increased T1-to-T2 time period were risk factors for apical root resorption of the central incisors; normal root form and wide roots were preventive factors, with an explained variance of 14%. Similarly, long roots, narrow roots, and increased T1-to-T2 time period were risk factors for resorption of the lateral incisors, whereas normal root form was a preventive factor, with an explained variance of 24%. Parameters associated with use of rectangular wire, presence of incisor irregularity, and history of trauma were not identified as risk factors. Use of elastics was not included in the regression analyses. CONCLUSIONS: Root resorption can begin in the early leveling stages of orthodontic treatment. About 4.1% of patients studied had an average resorption of 1.5 mm or more of the 4 maxillary incisors, and about 15.5% had 1 or more maxillary incisors with resorption of 2.0 mm or more from 3 to 9 months after initiation of fixed appliance therapy. Although teeth with long, narrow, and deviated roots are at increased risk of resorption during this early stage, the explained variance of these risk factors is less than 25%.     

A radiographic comparison of apical root resorption after orthodontic treatment with 3 different fixed appliance techniques.

Apical root resorption is an undesirable, but frequent side effect of orthodontic treatment, and therefore improvements in orthodontic techniques and materials are in constant development to decrease it. One of the most recently developed orthodontic techniques is the Bioefficient Therapy that uses contemporary orthodontic materials. Therefore, the primary objective of this study was to compare the amount of root resorption after orthodontic treatment between the simplified standard edgewise technique (group 1), the edgewise straight wire system (group 2), and the Bioefficient Therapy (group 3). It was also the purpose of this investigation to evaluate the amount of root resorption in the whole sample studied and the prevalence of root resorption in the upper and lower incisors. Thus, periapical radiographs were obtained with the long cone paralleling technique for the upper and lower incisors from 30 patients for each group. Root resorption was ranked by scores by 2 examiners who had an excellent intra and interexaminer calibration by Kendall concordance coefficient. Results of the Kruskal-Wallis test demonstrated that group 3 (Bioefficient Therapy) presented less root resorption than the others. It was speculated that the factors responsible for the lesser resorption in this technique were the use of heat-activated and superelastic wires with the bracket design in this technique as well as the use of a smaller rectangular stainless steel wire (0.018 x 0.025 inch) in a 0.022 x 0.028 inch slot during incisor retraction and the finishing stages, as compared to the other techniques. Considering the whole sample, there was no root resorption in 2.25% of the analyzed teeth. There was only a slight resorption in 42.56%, a moderate resorption in 53.37%, an accentuated resorption in 1.40% and an extreme root resorption in only 0.42% of the teeth. The prevalence of resorption for each incisor indicated, in decreasing order, a greater resorption for the upper centrals, followed by the upper laterals, lower centrals, and lastly the lower lateral incisors.     

Radiographic evaluation of apical root resorption with 2 different types of edgewise appliances

Summary The purpose of this paper was to compare radiographically the prevalence and degree of apical root resorption after treatment with a fully programmed edgewise appliance (FPA) and a partly programmed edgewise appliance (PPA) in a randomized multipractice clinical trial. Two groups of patients with Class II malocclusions were treated orthodontically. The type of treatment was randomly assigned by a computer program. During fixed appliance therapy, one group was treated according to the precepts of the straight wire concept (FPA; n=32) while the other was treated with conventional full edgewise mechanics (PPA; n=29). Treatment times were recorded. Radiographs of the maxillary incisors were made before and after active treatment with fixed appliance using the bisecting angle technique. To correct for different projecting angles the pairs of radiographs were digitally reconstructed. The prevalence and degree of root resorption were assessed. The mean treatment time was 1.8 years and 1.6 years for treatment with FPA and PPA, respectively. The mean amount of loss of tooth length was 8.2% for the patients treated with FPA and 7.5% for the patients treated with PPA. No statistically significant differences could be assessed between both groups at the end of active treatment. The mean prevalence of apical root resorption was 75% for the patients treated with FPA and 55% for the patients treated with PPA. Statistical evaluation showed no significant differences. We concluded that the prevalence and degree of root resorption is independent of the appliances as used in this study.     

全景片及CBCT对不同前磨牙拔除模式上颌中切牙根吸收的诊断研究

目的　采用全景片及CBCT测量不同前磨牙拔除模式对上中切牙根吸收的影响。方法　正畸患者27例分为3组：T0（不拔牙组）、T1（拔除第一前磨牙组）和T2组（第二前磨牙组）,所有患者治疗前后均拍摄全景片和CBCT,对各组上切牙根吸收进行测量。结果　3组患者正畸治疗后均出现不同程度的牙根吸收现象。CBCT测量显示,T1和T2组的中切牙牙根吸收较T0组显著。而T1组的根吸收量大于T2组(P < 0.05);全景片测量表明,T0组和T2组根吸收差异不显著,T1组的根吸收量大于T0组。CBCT与全景片测量比较,T1和T2组差异无显著性,T0组差异有显著性。结论　不同的拔牙模式会对上切牙的根吸收产生不同的影响。CBCT测量的灵敏度要大于全景片。     

青少年与成人正畸治疗前后上前牙冠根比变化的初步研究

目的探讨直丝弓矫治器矫治前后牙齿冠根比的变化规律,及年龄因素在其中所起的作用。方法选取青少年患者23例和成人患者23例共46例,分为青少年组和成年组,根据正畸治疗前后全口曲面断层片,以托槽为参照系,测量计算出治疗前后中切牙、侧切牙及尖牙的根尖吸收量、牙槽嵴吸收量及冠根比变化量,进行配对t检验,分析年龄因素与矫治前后冠根比变化的相关性。结果青少年组治疗前后中切牙平均冠根比分别为0.62±0.04,0.70±0.06;侧切牙平均冠根比分别为0.63±0.04,0.70±0.06;尖牙平均冠根比分别为0.54±0.05,0.60±0.06。成年组治疗前后中切牙平均冠根比分别为0.67±0.04,0.78±0.06;侧切牙平均冠根比分别为0.66±0.05,0.77±0.05;尖牙平均冠根比分别为0.57±0.05,0.70±0.06。各组治疗前后冠根比有显著性差异,成年组上前牙冠根比变化量较青少年组显著(P<0.01)。结论直丝弓矫治后,上前牙冠根比均明显增大,其中成年组较青少年组显著,但都仍在临床可接受的正常范围内。