正畸治疗中年龄因素对牙根吸收影响的研究

目的　探讨年龄因素在正畸治疗中对牙根吸收的影响作用。方法　配对测量正畸治疗前后牙根长度及牙根等级 ,分析牙根吸收及其分布情况。结果　正畸治疗前后牙根长度改变有组间差异 (P <0 .0 1)。正畸治疗前后牙根吸收等级分布没有组间差异 (P >0 .0 5 )。结论　正畸治疗中年龄因素并不是造成牙根吸收最重要的因素 ,它对牙根吸收的影响是有限的。     

面型对正畸支抗牙牙根吸收影响的临床研究

目的 探讨不同面型在正畸治疗中对支抗牙牙根吸收的影响。方法 选择120例经方丝弓矫治器治疗的患者,按面型分为高角型、正常型、低角型3个组,每组患者治疗前后分别拍摄头颅侧位定位片,配对测量分别被确定作为支抗的后牙或前牙正畸治疗前后牙根长度,将牙根长度改变量以计算机进行统计分析,并评价牙根吸收情况。结果3组病例正畸治疗前后支抗牙牙根长度改变有统计学意义(P<0.001)。3组之间相对应牙齿的牙根吸收量不同,高角型病例牙根吸收轻,而低角型病例牙根吸收重。组间不同的吸收量差异有统计学意义(P<0.01)。结论 在正畸治疗中不同面型对支抗牙牙根吸收程度有不同影响,面型是影响支抗牙牙根吸收的一个重要因素。     

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。     

Orthodontic-induced External Root Resorption of Endodontically Treated Teeth: A Meta-analysis

Introduction

The difference in the amount of orthodontic-induced external root resorption (OIERR) of endodontically treated teeth (ETT) compared with vital pulp teeth (VPT) treatment is controversial. This systematic review and meta-analysis assessed the available evidence regarding OIERR of ETT compared with VPT.

正畸治疗中拔牙与牙根吸收关系的临床研究

目的评价拔牙对正畸治疗中的牙根吸收的影响。方法选取120例年龄在11～18岁经方丝弓矫治器固定矫治治疗的青少年,分为拔牙组和不拔牙组,两组病人治疗前后分别拍摄全口曲面断层片,牙根形态按等级分级,计算机进行统计分析各等级频数分布变化。结果两组病例在治疗后牙根吸收均以1、2级居多、拔牙组治疗后牙根3、4级吸收多于未拔牙组,两组之间的差异有显著性(P<0.001)。结论拔牙治疗会加重正畸治疗中的牙根吸收。     

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。     

正畸治疗前倾阻生的下颌第三磨牙的根吸收风险研究

目的：探讨矫治前倾阻生下颌第三磨牙后牙根的改变和根吸收的影响因素,为临床医师提供风险预测的依据。方法：样本共10例（女性8名,男性2名,年龄15～32岁）,下颌第一恒磨牙已拔除或无保留价值,且伴同侧下颌第三磨牙前倾至水平阻生。矫治采用直丝弓矫治器,利用口内辅弓法后推下颌第三磨牙,再通过竖直簧直立第三磨牙。直立前、后拍摄全口曲面断层片进行测量。采用两相关样本非参数检验（Wilcoxon Signed Ranks Test）对矫治前后牙根长度的改变进行对比分析。结果：经过治疗,10例病例都取得满意的疗效。矫治后成人组阻生磨牙根长度有所减少,但未见统计学差异。青少年组牙根长度增加,差异具有显著性（P〈0.05）。结论：通过正畸手段直立阻生磨牙具有可行性和可靠性,为科学的权衡各种治疗方法提供帮助,为患者提供安全、有效的治疗方案。     

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。     

Cone Beam Computed Tomography for Assessment of Root Length and Marginal Bone Level during Orthodontic Treatment

Objective:To evaluate the accuracy and precision of cone beam computed tomography (CBCT) with regard to measurements of root length and marginal bone level in vitro and in vivo during the course of orthodontic treatment.Materials and Methods:Thirteen patients (aged 12–18 years) from an ongoing study and a dry skull were examined with CBCT using multiplanar reformatting for measurements of root length and marginal bone level. For in vivo evaluation of changes in root length, an index according to Malmgren et al was used, along with a modification of this method.Results:The in vitro mean difference between physical and radiographic measurements was 0.05 mm (SD 0.75) for root length and −0.04 mm (SD 0.54) for marginal bone level. In vivo the error was <0.35 mm for root length determinations and <0.40 mm for marginal bone level assessments.Conclusion:Despite changes in tooth positions, the CBCT technique yields a high level of reproducibility, enhancing its usefulness in orthodontic research.     

Root Surface Changes in Endodontically Treated Teeth following Orthodontic Movement

IntroductionOrthodontically induced external root resorption has been labeled an unavoidable consequence of orthodontic tooth movement (OTM). The objective of this study was to investigate the change in surface area (mm²) and volume (mm³) of endodontically treated teeth (ETT) compared with contralateral teeth with a vital pulp (VPT) after OTM.MethodsSeventy-six teeth were included in this retrospective analysis: ETT (n = 38) and VPT (n = 38). All teeth were evaluated using cone-beam computed tomographic imaging at 2 time periods: before OTM (T1) and after OTM (T2). Study teeth were segmented to include all areas contained within the lamina dura and then were converted into a mesh model for data calculation. The surface area (mm²) and volume (mm³) of each tooth were calculated at T1 and T2 based on the number of cubic voxels present within the mesh model. Statistical analysis was performed using a linear mixed-effects model.ResultsThe average change in surface area after OTM in ETT was 13.01 mm² and 19.95 mm² in VPT (P < .05). The average percent change in surface area after OTM in ETT was 2.09% and 3.38% in VPT (P < .05). The average change in volume after OTM in ETT was 22.48 mm³ and 32.44 mm³ in VPT (P < .05). The average percent change in volume after OTM in ETT was 2.62% and 4.10% in VPT (P < .05).ConclusionsThe results from this study suggest that ETT are less susceptible to root resorption after OTM than their vital counterparts.     

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。     

猫下颌尖牙根管治疗对牙正畸移动的影响

目的：探讨经根管治疗牙的正畸移动可行性及牙根吸收的风险.方法：建立对经根管治疗牙进行正畸移动的动物模型,采用石膏模型测量、病理学和放射学方法评估正畸移动的距离及牙根吸收的程度.16只成年家猫的一侧下颌尖牙在全麻下开髓、拔髓,一次完成根管充填治疗术,随后在正畸弹簧的作用力（100～120 g）下向远中作倾斜移动.8周后测量石膏模型上牙移动的距离,以及根管治疗牙与正常牙的组织学和放射学牙根长度.应用SPSS11.0软件包进行数据分析,均数比较采用配对t检验.结果：实验结果显示,在相同正畸力作用下,根管治疗牙与正常牙移动距离相近（P＞0.05）;组织病理学显示,根管治疗牙牙根的长度比正常牙小（P＜0.05）,但在放射学上,两者的长度无统计学差异（P＞0.05）.结论：在本实验条件下,经根管治疗牙在正畸力作用下能与正常牙同样快速移动,组织学观察显示其根吸收的程度比后者略大.     

口泰用于根管超声冲洗抗菌效果的研究

目的 :研究口泰与超声波联合应用杀灭感染根管内厌氧菌的效果。方法 :将 6 0例慢性根尖周炎患者共 6 0颗患牙随机分为 3组 ,每组各 2 0颗患牙 ,第 1组常规法手持器械根管预备及常规针筒式根管冲洗 ,第 2、3组均用超声法进行根管预备并分别以生理盐水、口泰作为超声冲洗液 ,根管预备前后分别取样进行厌氧培养。结果 :第 2组厌氧菌减少程度明显大于第 1组 (P <0 .0 5 ) ;第 3组厌氧菌减少程度明显大于第 2组 (P <0 .0 1) ,显著大于第 1组(P <0 .0 0 1)。结论 :超声波在根管杀菌方面有独特的优势 ,口泰可有效杀灭感染根管内厌氧菌 ,是一种较理想的根管超声冲洗液     

直丝弓矫治器不同治疗阶段的根吸收状况研究

目的：通过观察直丝弓矫治不同阶段牙根长度的变化情况,分析直丝弓矫治与根吸收的关系。方法：50名正畸患者,分别在治疗前（T1）、转矩阶段开始（T2）及治疗后（T3）3个阶段对同一象限的上中切牙及侧切牙进行平行投照,通过计算并分析根吸收状况。结果：直丝弓矫治过程中,前牙牙根长度受到影响,特别是加入转矩力后,根吸收趋势更加明显,但所有根吸收都没有超过根长的1／3。结论：直丝弓矫治可能会造成切牙根吸收,在加入转矩力后这种根吸收趋势更加明显,但是,在正常情况下,这种矫治技术不易造成中度以上的根吸收。     

Apical root resorption due to orthodontic treatment detected by cone beam computed tomography

Objective:To determine the frequency of apical root resorption (ARR) due to orthodontic treatment using cone beam computed tomography (CBCT) in a sample of 1256 roots from 30 patients.Materials and Methods:All patients had Class I malocclusion with crowding. Of the 30 patients evaluated, 11 were boys and 19 were girls; their mean age was 13 years (11 to 16 years). Orthodontic treatment followed the nonextraction treatment. CBCT images were obtained before and after orthodontic treatment, and ARR was determined using Axial Guided Navigation of CBCT images.Results:All patients had ARR. No statistically significant association was found between resorption frequency, gender, and age. ARR was detected using CBCT in 46% of all roots that underwent orthodontic treatment.Conclusions:CBCT was effective for detecting in vivo even minimal degrees of ARR due to orthodontic treatment and allowed three-dimensional evaluation of dental roots and visualization of palatine roots of maxillary molars. The highest frequencies and the most significant ARR occurred in incisors and distal roots of first maxillary and mandibular molars.     

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。     

面型对正畸治疗中牙根吸收影响的临床研究

目的 评价面型对正畸治疗中出现的牙根吸收的影响。方法 选用120例经方丝弓矫治器固定矫治的青少年，按面型分为高角型、正常型、低角型三个组，每组病人治疗前后分别拍摄全口曲面断层片，配对测量正畸治疗前后牙根等级，将牙根各等级改变的频数量以计算机进行统计分析。结果 三组面型的病例正畸治疗前后牙根等级分布改变有显著的统计学意义(P＜0．001)。三组之间组间差异的表现各不相同。高角型病例牙根吸收最轻，而低角型病例易出现重度牙根吸收。三组病例组间差弄有显著的统计学意义(P＜0.01)。结论 在正畸治疗中不同面型对牙根吸收程度有显著的影响，是影响牙根吸收的一个重要因素。     

口腔医学生临床前离体牙及人工根管根管治疗教学研究

目的：通过离体牙、人工根管培养实习医生了解并掌握根管治疗的标准程序和方法。方法：选择正畸患者拔除离体牙36颗、牙髓病及牙周病拔除离体牙42颗,人工根管4颗,分组采用常规改良逐步后退法、冠向逐步深入法进行根管处理、预备及充填,观察实习医生根管治疗掌握情况及模拟治疗效果。结果：离体牙采用改良逐步后退法时,前牙根管治疗成功率〉前磨牙〉磨牙（P〈0.05）;离体牙磨牙组中,采用冠向逐步深入法成功率高于逐步后退法（P〈0.01）。结论：采用人工根管可以直观的辅助实习医生体会弯曲根管的治疗,结合离体牙进行根管治疗训练可以提高加深实习医生对根管解剖结构、不同根管治疗方法的了解,对于实习医生临床前培养有明显效果。     

Root and Bone Response to the Proximity of a Mini-Implant under Orthodontic Loading

Objective:To determine the histological reaction of the root and bone as a mini-implant approaches the root.Materials and Methods:Two kinds of mini-implants were inserted into the buccal alveolar bone of 4 beagles (2 males and 2 females). The specimens were classified as the near-root group, the PDL contact group, the root contact group, and the root perforation group. Cementum resorption, dentin resorption, cementum repair, cementum growth, ankylosis, root cracking, and root fracture were assessed as the implant neared the root.Results:The incidence of root resorption increased when the mini-implant was less than 0.6 mm from the root in the near-root group and PDL contact group. Root cracking and root fracture occurred in the root contact group and root perforation group. Bone resorption and ankylosis were observed in some specimens. However, some specimens of the PDL contact group and root contact group had cementum growth or little root resorption despite proximity to the root. In the root perforation group, root resorption and ankylosis occurred on the side opposite the insertion.Conclusions:There is a risk of root contact and severe tissue damage from a thick mini-implant and the drilling procedure, either of which can induce root resorption or ankylosis. Use of smaller mini-implants may reduce root contact and tissue damage. However, the small mini-implant may need enhancement of its stability.