Repair of Extensive Apical Root Resorption Associated with Apical Periodontitis: Radiographic and Histologic Observations after 25 Years

Introduction

Root resorption is a frequent finding in teeth with apical periodontitis. In cases of severe apical periodontitis, root resorption may involve not only cementum but also dentin. Resorbed tooth structures can only be repaired with cementum because stem cells in the periradicular tissues are not capable of differentiating into odontoblasts. This article reports the repair of extensive apical root resorption associated with apical periodontitis 25 years after treatment.

Methods

A 51-year-old man presented with pulp necrosis and symptomatic apical periodontitis in tooth #7. The periapical radiograph showed a large radiolucent periradicular lesion and severe root resorption. Nonsurgical root canal therapy was performed. Twenty-five years after treatment, a crown fracture developed, and the tooth could not be restored. The periapical radiograph revealed complete healing of the previous apical periodontitis lesion and restoration of the resorbed root structure. The tooth was removed and examined histologically.

Results

The apical canal was almost completely filled with a cementumlike tissue with some strands of entrapped vital uninflamed connective tissue. Areas of cementum and dentin resorption in the apical third were repaired by a combination of cellular and acellular cementum to which periodontal ligament fibers were attached.

Conclusions

Root resorption caused by apical periodontitis can be restored almost to its normal structure after adequate nonsurgical root canal treatment that succeeded in controlling infection. The mechanisms behind this process are not clear but probably involve signaling pathways regulating root development, cell-cell and cell-matrix interaction, and morphogens.     

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。     

正畸治疗中牙根吸收的原因分析

目的：探讨患者的年龄、性别在正畸治疗中对牙根吸收的影响。方法：选用128例经直丝弓矫治器矫治完成的病例,患者治疗前后分别拍摄全口曲面断层片,测量不同年龄、性别组治疗前后上、下颌前牙的牙根长度变化。结果：成人组与儿童组上颌前牙正畸治疗前后牙根吸收差别无统计学意义,而下颌前牙正畸治疗前后牙根吸收差别有统计学意义（P〈0.05）;不同性别组上、下颌前牙正畸治疗前后牙根吸收差别无统计学意义。结论：年龄是正畸治疗中影响牙根吸收的一个重要因素。     

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。     

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。     

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。     

Root Resorption

A bstract — Over the past years a great deal of work has been done in the field of tooth root resorption but notwithstanding this, understanding of the subject has progressed very little. This paper reviews the subject and suggests ways of minimizing root resorption or perhaps even eliminating it.     

Effects of Pulpectomy on the Amount of Root Resorption during Orthodontic Tooth Movement

Introduction

Previous studies have revealed that orthodontic force affects dental pulp via the rupture of blood vessels and vacuolization of pulp tissues. We hypothesized that pulp tissues express inflammatory cytokines and regulators of odontoclast differentiation after excess orthodontic force. The purpose of this study was to investigate the effects of tensile force in human pulp cells and to measure inflammatory root resorption during tooth movement in pulpless rat teeth.

Methods

After cyclic tensile force application in human pulp cells, gene expression and protein concentration of macrophage colony-stimulating factor, receptor activator of nuclear factor kappa-B ligand, interleukin-1 beta, and tumor necrosis factor alpha were determined by real-time polymerase chain reaction and enzyme-linked immunoassay. Moreover, the role of the stretch-activated channel was evaluated by gadolinium (Gd³⁺) treatment. The upper right first molars of 7-week Wistar rats were subjected to pulpectomy and root canal filling followed by mesial movement for 6 months.

Results

The expression of cytokine messenger RNAs and proteins in the experimental group peaked with loading at 10-kPa tensile force after 48 hours (P < .01). Gd³⁺ reduced the expression of these cytokine messenger RNAs and protein concentrations (P < .01). The amount of inflammatory root resorption was significantly larger in the control teeth than the pulpectomized teeth (P < .05).

Conclusions

This study shows that tensile forces in the pulp cells enhance the expression of various cytokines via the S-A channel, which may lead to inflammatory root resorption during tooth movement. It also suggests that root canal treatment is effective for progressive severe inflammatory root resorption during tooth movement.     

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。     

Internal Resorption Complicating Orthodontic Tooth Movement

Abstract

A case report is presented of an orthodontic patient who suffered internal resorption and a consequent ‘pink spot’ affecting a maxillary central incisor. Its management is outlined. The aetiology and possible cellular events responsible are discussed.     

Comparison of Orthodontic Root Resorption of Root-filled and Vital Teeth Using Micro–computed Tomography

ObjectiveTo evaluate the difference in orthodontic root resorption between root-filled and vital teeth.Material and MethodsSixteen individuals who required bilateral premolar tooth extraction due to orthodontic treatment and had a previously root-filled premolar tooth on one side were included in the study. The experimental group consisted of root-filled premolar teeth, and the control group consisted of contralateral vital premolar teeth. A 150-g buccally directed force was applied to these teeth using 0.017 × 0.025-inch TMA cantilever springs. The premolars were extracted 8 weeks after the application of force. Images were obtained using micro–computed tomography. Resorption measurements were obtained using the Image J program.ResultsThe mean values for resorption were 0.08869 mm³ for the root-filled teeth and 0.14077 mm³ for the contralateral teeth, indicating significantly less resorption for the root-filled teeth compared with the contralateral teeth after the application of orthodontic force (P = .003). In both groups, the most resorption was seen on the cervical-buccal and apical-lingual surfaces. The mean resorption value of the cervical region was 0.06305 mm³ in the control group and 0.0291 mm³ in the experimental group, and the difference was statistically significant (P = .002).ConclusionsRoot-filled teeth showed significantly less orthodontic root resorption than vital teeth.     

The Use of Microimplants in Lingual Orthodontic Treatment

Currently excellent clinical results can and are being achieved with lingual orthodontics. For many patients, due to esthetic considerations, this is their only choice. Certain orthodontists may still feel reluctant or hesitant to attempt this form of therapy; however, several articles^{7, 8, 9, 10 and 11} have shown that with the indirect bonding techniques available, by using straight wire principles and making use of microimplants for anchorage, the technique has been greatly simplified and has introduced significant treatment alternatives in 21st century orthodontics.