青少年正畸治疗中影响牙根吸收的因素探讨

目的：探讨影响青少年错[牙合]畸形患者正畸矫治后牙根吸收的相关因素。方法：选择已完成正畸固定矫治的青少年患者78例．在其矫治前后的曲面断层片上,对4个上切牙进行根尖形态的分析,以获得正畸矫治后牙根吸收的定性数据。在对受试者按年龄、性别、牙位、牙龄、拔牙与否及疗程分组后,利用SPSS12．0软件对所得数据进行非参数检验分析。结果：所有正畸患者都存在一定程度的牙根吸收,根尖形态分析显示：①牙龄ⅣA期患者比ⅢC期的患者存在更严重的牙根吸收（P〈0．01）,但按年龄比较不存在显著差异;②拔牙组比不拔牙组有更加严重的牙根吸收（P〈0．01）;③疗程越长,牙根吸收也越明显（P〈0．05）;④牙根吸收的严重程度与性别及上切牙牙位之间无相关性。结论：在第二恒磨牙完全建验前（ⅣA期前）进行正畸治疗、不拔牙矫治、缩短矫治疗程,均可以减少正畸治疗中的牙根吸收。     

正畸治疗对根管治疗牙及对侧同名活髓牙根吸收影响的Meta分析

目的    分析正畸治疗对根管治疗牙及对侧同名活髓牙根吸收的影响。方法    计算机检索Cochrane Library、PubMed、Embase、Google Scholar、中国知网、万方等数据库,查找研究根管治疗牙经正畸治疗后牙根吸收情况的相关文献。应用Meta分析比较正畸治疗对根管治疗牙及对侧同名活髓牙根吸收的影响。结果    纳入了10篇相关文献。Meta分析结果发现,正畸治疗患者根管治疗牙根吸收情况与对侧同名活髓牙比较,差异无统计学意义（P > 0.05）。在男性正畸治疗患者中,根管治疗牙牙根吸收量小于对侧同名活髓牙,差异有统计学意义（P < 0.05）;而女性正畸治疗患者两侧牙根吸收量比较,差异无统计学意义（P > 0.05）。正畸治疗方式（拔牙矫治与非拔牙矫治）和牙位（前牙与后牙）对正畸治疗患者根管治疗牙及对侧同名活髓牙根吸收的影响比较,差异均无统计学意义（均P > 0.05）。结论    正畸治疗过程中移动根管治疗后的牙齿是一种相对安全的操作。     

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目的    评价上中切牙正畸治疗后根吸收状况,探讨影响根吸收的相关因素。方法    从大连大学附属口腔医院正畸科2名资深医生2007年5月至2009年12月所完成的正畸病例中,随机选择233例（男85例,女148例）。分为成人组90例,平均年龄（21.73 ± 3.68）岁;青少年组143例,平均年龄（13.37 ± 1.81）岁。通过分析治疗前后的头颅侧位片观察上中切牙牙根形态与长度变化,评价上中切牙根吸收状况。结果    233例患者中的13例上中切牙发生了不同程度的根吸收,根吸收发生率为5.58%。成人女性拔牙矫治组的上中切牙根吸收程度高于青少年女性拔牙矫治组,差异有统计学意义（P < 0.05）。青少年组中,女性拔牙矫治患者的根吸收程度较男性拔牙矫治患者明显,差异有统计学意义（P < 0.05）。而是否拔牙,其上中切牙根吸收程度差异无统计学意义（P > 0.05）。结论    女性拔牙矫治患者治疗后的上中切牙根吸收发生率较高。正畸根吸收原因复杂,治疗前应详细分析各种根吸收易发因素,以减小正畸根吸收的发生和程度,维持正畸牙齿的健康。     

异常牙根形态对正畸治疗前后前牙根吸收的影响

目的 调查异常牙根形态在正畸治疗前后对牙根吸收的影响。方法 随机选择经直丝弓矫治技术完成的病例153例,分析患者治疗前后的全口曲面断层片,将前牙按根形态分为正常组、短根组、钝根组、弯根尖组及滴管状根组5组,以Levander和Malmgren的牙根吸收分级法记录每个前牙牙根根吸收程度,将牙根根吸收程度及其改变的频数进行统计分析。结果 前牙中异常根形态的发生率为16.92%,以弯根尖与钝根最为常见;根形态异常组与正常组的根吸收均值间在正畸治疗前有显著性差异（P<0.05）,正畸治疗后亦有显著性差异（P<0.01）,其中短根组根吸收值最高,其次为滴管状根组;根形态异常组在正畸治疗前后的根吸收发生率均较正常组高,差异有显著性（P<0.01）。结论 异常牙根形态能显著增加牙根吸收的发生率和严重程度。     

固定正畸前后牙根吸收的部分影响因素分析

目的 :研究正畸治疗前后与牙根吸收相关的临床因素。方法 :随机选择经过固定正畸治疗 ,有清晰可辨的矫治前后全口曲面断层片的病例 96例。用根吸收分级评估法记录每人矫治前后全口牙齿根吸收情况。分析牙根吸收与性别、年龄、拔 (不拔 )牙、不同牙位、疗程和治疗前牙根状况的关系。结果 :(1)不同性别间 ,根吸收表现没有具统计学意义的差别。 (2 )比较拔牙与非拔牙组间的根吸收情况及治疗时间 ,两组间发现明显差别。 (3)通过两两相关分析 ,发现患者年龄与疗程无相关关系。然而年龄与治疗前后上颌牙齿的根吸收相关。减数及疗程与正畸后平均根吸收值相关。(4 )通过多元相关分析 ,发现年龄和疗程较减数与根吸收的关系更密切。另外 ,治疗后的根吸收与治疗前存在的牙根吸收相关 ,特别表现在前牙区。结论 :(1)性别对牙根吸收无明显影响。 (2 )年龄及疗程对根吸收有一定影响。 (3)拔牙不是造成根吸收的直接因素 ,而是通过其对疗程的影响间接影响牙根状况。 (4 )若某牙治疗前存在根吸收 ,则正畸后该牙有可能表现出更明显的根吸收。     

青少年安氏Ⅰ类固定矫治牙根吸收的临床研究

目的探讨青少年安氏Ⅰ类患者固定正畸治疗后牙根吸收的影响因素。方法选择100例年龄小于18岁的安氏Ⅰ类患者分成牙根发育完成组与牙根发育未完成组，均采用MBT技术矫治，矫正前后拍摄全口曲面断层片，以改良根吸收分级法评估治疗前后牙根吸收情况，探讨牙根吸收与性别、牙根发育、拔牙与否的相关性。结果①牙根发育完成组矫治后根吸收加重，差异有统计学意义（P〈0．01）；牙根发育未完成组矫治前后牙根吸收差异无统计学意义（P〉0．05）。②青少年男、女组间的根吸收差异无统计学意义（P〉0．05）。③拔牙组根吸收者多于未拔牙组，差异有统计学意义（P〈0．05）。结论拔牙与否、牙根发育完成与否是影响安氏Ⅰ类患者固定矫治后牙根吸收的部分因素，而性别因素与根吸收无明显的关系。     

固定正畸后牙根吸收的部分影响因素分析

目的　研究影响正畸治疗后牙根吸收的部分临床因素。方法　随机选择经过固定正畸治疗 ,有清晰可辨的矫治前后全口曲面断层片者 96例。以改良根吸收分级法评估每名患者矫治前后全口牙齿根吸收情况。通过多元方差分析及多元回归分析 ,探讨正畸后平均根吸收值 (rootresorptionaftertreatment ,RRAT )与性别、年龄、减数与否、部位、疗程和治疗前平均根吸收值 (rootresorptionbeforetreatment,RRBT )的关系。结果　①女性RRAT校正均值为 0 4 1,男性为 0 34,差异有高度显著性 (P <0 .0 5 )。②拔牙组的RRAT校正均值为 0 4 3,未拔牙组为 0 31,差异有高度显著性(P <0 .0 0 1)。③前牙区RRAT校正均值为 0 5 9,后牙区为 0 12 ,差异有高度显著性。④上牙RRAT校正均值为 0 4 0 ,下牙为 0 37,差异无显著性。⑤RRAT与年龄、疗程及RRBT呈正相关 ,复相关系数R =0 5 9,判定系数R2 =0 35。结论　性别、年龄、减数与否、疗程、部位及治疗前牙根状况对正畸治疗后牙根吸收均有影响。     

根管治疗牙正畸加力后根吸收的相关因素研究

目的研究固定正畸治疗对根管治疗牙牙根吸收的影响和相关因素分析。方法选择正畸治疗前口腔内已完善根管治疗牙45例,利用治疗前后的全口曲面断层片,以改良根吸收分级法评估患者治疗前后牙根形态变化,分析正畸治疗对根管治疗后牙根吸收的影响。结果①正畸治疗后根管治疗牙牙根吸收有所增加,差异具有统计学意义（P〈0．001）;②性别是影响正畸治疗后根管治疗牙牙根吸收方程最为显著的因素（P〈0．05）,提示女性发生根吸收的风险大于男性;③正畸治疗后根管治疗牙与对侧活髓牙比较牙根吸收程度的改变差异没有统计学意义（P〉0．05）;④在所观察的样本中,无论根管治疗牙齿与活髓牙均未见3级根吸收。结论根管治疗牙在固定正畸治疗后可能发生一定程度的根吸收改变,但并不比活髓牙的风险更高。     

牙周炎致错位前牙正畸治疗后牙根吸收的临床研究

目的：观察牙周炎导致的唇向散开前牙经正畸治疗后牙根吸收情况,并与牙周健康的正畸患者进行比较。方法：选择安氏Ⅰ或Ⅱ1前牙散在间隙的成人牙周炎患者和牙周健康的成人正畸患者各12例,均无需拔牙,采用MBT直丝弓固定矫治,应用Nemoceph头影测量软件测量矫治前后前牙的牙冠与牙根比值,并作配对t检验,判断其牙根吸收程度。结果：矫治后两组均有轻度牙根吸收（P〈0.05）,牙周炎组牙根吸收程度较牙周健康组大,但二组间差别无统计学意义。结论：牙周炎患者和牙周健康患者正畸治疗后牙根均有一定程度吸收,但是可接受的。牙周炎患者通过正畸关闭前牙散在间隙并不会加重牙根吸收。     

正畸治疗前后牙根吸收的临床研究

目的 调查正畸治疗前后牙根吸收的临床特征。方法 随机选择至少经过十二个月固定正畸治疗,有清晰可辨的矫治前后全口曲面断层片的病例９６例,用根吸收分级评估法记录每人矫治前后全口牙齿根吸收情况,并统计分析。结果 （１）正畸治疗前８．６％的牙齿存在根吸收,治疗后４１．６％的牙齿有程度不等的根吸收;（２）治疗前的根吸收绝大部分为轻度,治疗后仍以轻度吸收为主,但也有部分中重度吸收;（３）治疗前的根吸收主要在上颌前牙区;治疗后根吸收上下颌没有显著性差异,但前牙明显高于后牙。结论（１）正畸后的根吸收较为常见;（２）大部分正畸过程中的牙根吸收是可接受的;（３）正畸治疗后有一部分牙齿（１．３％）出现重度根吸收,主要分布于上前牙,成为危害患者颜面美观及功能的隐患,应引起足够的重视。     

自锁托槽和传统托槽对上颌切牙牙根外吸收影响的回顾性研究

目的：评价自锁托槽和传统托槽在正畸治疗中对牙根外吸收的影响。方法：选取南京同仁医院口腔科矫治结束的固定正畸患者72例为研究对象,36例采用自锁托槽,36例采用传统托槽。对不同托槽组的临床资料进行描述性分析,并根据正畸治疗前后全颌曲面断层片和记存模型,测量计算出不同托槽的牙根外吸收量,进一步以牙根外吸收量为因变量,对临床相关因素包括托槽的类别、疗程、性别、减数与否、年龄进行回归分析。结果：两组患者问的疗程、性别、减数与否、年龄的临床统计资料,其两组间分布无差异;治疗疗程对牙根外吸收的影响有显著意义,自锁托槽在对牙根外吸收的影响方面与传统托槽相比有增加的趋势,但无统计学差异（P=0．06）。结论：无论是自锁托槽还是传统托槽,均可造成切牙根外吸收,治疗疗程对牙根外吸收的影响有显著意义,自锁托槽对正畸治疗过程中牙根外吸收的影响与传统托槽相比,有增加趋势,但无统计学差异。     

牙周炎患者排齐整平阶段牙根吸收的比较研究

目的:比较研究牙周炎患者和牙周健康患者在正畸治疗的排齐整平阶段牙根吸收的情况。方法:选择成年错牙合畸形患者60例,轻度牙周炎患者和牙周健康者各30例,均不需拔牙,MBT直丝弓固定矫治,排挤整平过程中不同时间点:0个月(T0)、1个月(T1)、6个月(T2),分别拍摄两组病例上下前牙的数字化平行定位投照根尖片,统计各牙不同时期的牙根长度X0、X1、X2,及牙根吸收量X(0-1)和X(0-2)。结果:实验组和对照组在T1和T2期,均发生很轻微的牙根吸收,但两组间不同时间点牙根吸收量X(0-2)、X(0-1),差异无统计学意义。结论:MBT正畸治疗的不拔牙病例排齐整平阶段中,牙周炎患者和牙周健康患者均会发生很轻微(都小于1 mm)牙根吸收,但二者之间牙根吸收量无差异。     

Volumetric cone-beam computed tomography evaluation and risk factor analysis of external apical root resorption with clear aligner therapy

ObjectivesTo investigate the prevalence and severity of external apical root resorption (EARR) volumetrically with clear aligner therapy using cone-beam computed tomography (CBCT) as well as determine the possible risk factors and develop a prediction model for EARR.Materials and MethodsIn this retrospective study, 320 incisors from 40 Class II patients treated with aligners (Invisalign) were included in this study. CBCT images were obtained at pretreatment (T0) and posttreatment (T1). Root volume was calculated by three-dimensional reconstruction of CBCT images, and apical tooth movement was measured from superimposed CBCT images. Changes in root volume were compared using paired t-tests, and the relationship between root volume loss and potential risk factors was analyzed by multiple linear regression.ResultsAll of the measured incisors showed root volume loss, with an average of 11.48 ± 6.70 mm³, and the prevalence of severe resorption was 0.625%. The prediction model for EARR included variables of posttreatment sagittal root position (SRP), extraction, tooth type, and apical intrusion and extrusion displacements, with an R² of 0.51. Age, sex, duration, pretreatment SRP, attachment, advancement, and retraction movements were excluded from the model.ConclusionsMost incisors showed mild to moderate resorption during aligner treatment; only a minimal percentage showed severe resorption. Posttreatment SRP (which showed the highest association with EARR), extraction, tooth type, and apical intrusion and extrusion displacements were risk factors for EARR.     

Evaluation of maxillary central incisors on the noncleft and cleft sides in patients with unilateral cleft lip and palate—Part 2: Relationship between root resorption,horizontal tooth movement,and quantity of grafted autogenous bone

Objective:To evaluate the relationship between external apical root resorption (EARR) of the maxillary central incisors (U1), horizontal orthodontic tooth movement, and quantity of grafted bone in subjects with unilateral cleft lip and palate (UCLP) over an average duration of 8 years.Materials and Methods:Thirty subjects with UCLP were evaluated for EARR of U1 after edgewise treatment (T2). The teeth were classified as having no EARR, moderate EARR (combined into “no/moderate” EARR), or severe EARR. Frontal cephalometric radiographs acquired at eruption of U1 (T0), less than 6 months before secondary alveolar bone grafting (T1), and T2 were evaluated to determine the horizontal inclination (U1-axis angle) and distance of the root apex from the median line (U1-root–VL distance). On the cleft side, the quantities of grafted bone at less than 12 months postsecondary bone grafting and at T2 were evaluated using the alveolar bone graft (ABG) scale.Results:Cleft-adjacent teeth exhibited more severe EARR than did teeth on the noncleft side. The cleft side exhibited greater changes in U1-axis angle and U1-root–VL distance between T0 and T2 than did the noncleft side. On the cleft side, the ABG score at T2 in the severe EARR group was significantly lower than that in the no/moderate EARR group. These measurements were correlated with EARR grade.Conclusions:Cleft-adjacent U1 exhibited more severe EARR than did the U1 on the noncleft side, which might be associated with orthodontic treatment-induced changes in horizontal inclination and root apex movement. On the cleft side, severity of EARR may be correlated with the success of ABG.     

Genetic predisposition to external apical root resorption in orthodontic patients: linkage of chromosome-18 marker

External apical root resorption (EARR) is a common orthodontic treatment sequela. Previous studies implicate a substantial genetic component for EARR. Using a candidate gene approach, we investigated possible linkage of EARR associated with orthodontic treatment with the TNSALP, TNFalpha, and TNFRSF11A gene loci. The sample was comprised of 38 American Caucasian families with a total of 79 siblings who completed comprehensive orthodontic treatment. EARR was assessed by means of pre- and post-treatment radiographs. Buccal swab cells were collected for extraction and analysis of DNA. No evidence of linkage was found with EARR and the TNFalpha and TNSALP genes. Non-parametric sibling pair linkage analysis identified evidence of linkage (LOD = 2.5; p = 0.02) of EARR affecting the maxillary central incisor with the microsatellite marker D18S64 (tightly linked to TNFRSF11A). This indicates that the TNFRSF11A locus, or another tightly linked gene, is associated with EARR.     

External apical root resorption in Class II malocclusion: a retrospective review of 1- versus 2-phase treatment.

External apical root resorption (EARR) is an imperfectly understood problem of orthodontic treatment. The records of 138 children with Class II malocclusion (overjet > 7 mm) participating in a randomized clinical trial of early orthodontic treatment were reviewed. The patients were treated in either 1 phase with fixed appliances only (n = 49) or 2 phases with headgear (n = 49) or bionator (n = 40) followed by fixed appliances. The 3 groups were similar in age, sex, and malocclusion severity at enrollment. The records examined included anamnestic data, clinical examination records, panoramic radiographs before and after fixed appliance therapy, and posttreatment periapical radiographs. All radiographs were reviewed and scored independently by 2 examiners for maxillary incisor root development, morphology, and EARR. Of the 532 incisors scored, 11% of central and 14% of lateral incisors demonstrated moderate to severe (>2 mm) EARR. The proportion of incisors with moderate to severe EARR was slightly greater in the 1-phase treatment group. There was no difference in the incidence of EARR between teeth that had had trauma and those that had not, and there was only a slight increase in frequency of root resorption in teeth with unusual root morphology. Significant associations exist among EARR, the magnitude of overjet reduction, and the time spent wearing fixed appliances. However, not all incisors in a child respond in the same way, so other variables must play a role in determining the root response to orthodontic forces.     

Comparative study of root resorption of maxillary incisors in patients treated with lingual and buccal orthodontics

Objective:To compare the magnitude of external apical root resorption (EARR) of maxillary incisors in patients with mild to moderate anterior crowding, treated with lingual and conventional (labial) orthodontics.Materials and Methods:The sample comprised 40 patients divided into two groups: lingual (20 patients) and conventional buccal brackets (20 patients). Patient ages ranged from 11 to 45 years, and the study included 12 men and 28 women. Apical root resorption was measured from periapical radiographs obtained at the beginning of treatment (T1) and at the end of the leveling phase (T2). Periapical radiographs were scanned and transferred to the CorelDraw X7 image-processing program, in which measurements of root lengths were performed. For intragroup and intergroup comparisons between the T1 and T2 phases, paired and independent t-tests, respectively, were used at 5% significance.Results:There was significant apical root resorption for all teeth evaluated; the magnitude of the EARR (T2−T1) ranged from −0.35 mm to −0.63 mm in the lingual group, and from −0.66 mm to −0.85 mm in the conventional group. Although there was an intergroup variation in the magnitude of EARR observed, no statistically significant differences were found. Neither group presented any teeth with resorption ≥1 mm.Conclusions:The magnitude of apical root resorption in maxillary incisors in patients with anterior crowding was similar regardless of orthodontic technique, lingual or conventional. Both techniques resulting in an apical rounding considered clinically insignificant.     

External apical root resorption following orthodontic treatment

This study investigated the association of appliance type and tooth extraction with the incidence of external apical root resorption (EARR) of posterior teeth following orthodontic treatment. Pre- and posttreatment orthopantomograms were compared for 97 patients and a 4-grade ordinal scale used to measure EARR. The incidence of EARR was positively associated with tooth position (P < .001), appliance type (P = .038), and extractions (P = .001). This was observed in an overall analysis mutually adjusted for the effects of age at start of treatment, pretreatment overbite and overjet, use of headgear, tooth extraction, and type of appliance. The incidence of EARR was 2.30 times higher for Begg appliances compared with edgewise, and it was 3.72 times higher where extractions were performed.     

Apical root resorption in patients treated with comprehensive orthodontics

External apical root resorption (EARR) is a common--but seldom extreme--consequence of orthodontic treatment. Incisors are most at risk, perhaps because of their single roots and because they typically are moved farther than other teeth. We followed a cohort of patients (n = 153) treated with comprehensive orthodontics. EARR was scored on the upper incisors with a qualitative five-grade ordinal scale. There was no EARR at the start of treatment, but most (> 80%) exhibited slight-to-moderate EARR by the end of treatment (i.e., a loss of 1-2 mm). Cases treated with premolar extractions experienced more EARR because their incisors were retracted farther; however, the sum of the effects of patients' sex and age, and severity of the malocclusion, and the kind of mechanics used accounts for little of the overall variation in EARR. Instead, it appears that genetically-based inter-individual variation in susceptibility to EARR is the most influential factor. Research should be directed at understanding the biochemical nature of susceptibility so prospective patients can be screened to identify those at particular risk.     

自锁矫治与传统矫治对牙根吸收的影响

目的:探讨自锁托槽轻力矫治是否可以减轻对牙根的吸收。方法:选取临床治疗的安氏Ⅰ、Ⅱ类拥挤并拔除4颗第一前磨牙病例30例,分为2组。其中,15例使用Damon 3MX自锁托槽矫治(自锁组),15例使用传统结扎式直丝托槽矫治(结扎组)。2组资料矫治前在性别、年龄、拥挤度及错类型等指标上具有可比性。通过矫治前、后的模型及全口曲面体层片,测量计算2组矫治后上、下切牙牙根吸收量,应用SPSS19.0软件包对数据进行t检验分析。结果:①上颌中切牙牙根吸收自锁组为(2.05±1.51)mm,结扎组为(2.08±1.21)mm,差异无显著性(P=0.973>0.05)。②上颌侧切牙牙根吸收自锁组为(1.77±1.01)mm,结扎组为(1.91±1.59)mm,差异无显著性(P=0.848>0.05)。③下颌中切牙牙根吸收自锁组为(2.06±1.62)mm,结扎组为(1.98±1.50)mm,差异无显著性(P=0.926>0.05)。④下颌侧切牙牙根吸收自锁组为(1.94±1.45)mm,结扎组为(1.84±1.17)mm,差异无显著性(P=0.888>0.05)。结论:在拔牙正畸中,自锁矫治并未表现出比传统结扎矫治更少的牙根吸收。