微型种植体支抗压低犬切牙移动过程中牙周牙根骨性组织的变化（英文）

背景：牙齿压低移动更容易造成牙根吸收,以往针对矫正引起牙根吸收的研究或基于X射线片的回顾性临床研究,或因无法精确控制压低力量,结果误差较大。目的：建立应用微型种植体支抗压低犬切牙的实验动物模型,观察牙齿压低移动过程中牙周、牙根骨组织学的变化,以评价该治疗方法的可行性及安全性。方法：将9只犬分为5组：对照组1只,未加力;1周、2周、4周、12周组每组2只,在上颌两侧第二、三切牙牙根之间唇侧的牙槽间隔处植入微型种植体作为支抗,每侧施加100g的牵引力压低上颌两侧第一、二切牙,分别于加力后1,2,4,12周（主动加力4周,撤力后保持8周）时处死动物,将第一、二切牙连同牙龈、牙槽骨完整切取,制作组织学标本,苏木精-伊红染色,观察牙周、牙根的组织学变化。结果与结论：与对照组相比,1周组组织改建主要在根尖部和牙槽嵴顶,牙槽骨及牙骨质可见吸收,牙周膜局部出现玻璃样变性;2周组骨质吸收程度及范围明显扩大,吸收有从根尖部向根中及颈部扩展的现象;4周组骨质吸收仍然活跃,牙周膜玻璃样变性消失;12周组牙槽骨及牙骨质表面显著修复,骨陷窝新骨沉积,牙周膜排列有序。提示应用微型种植体支抗压低牙齿,早期组织变化主要在根尖部和牙槽嵴顶,表现为牙槽骨及牙骨质吸收、牙周膜玻璃样变性。随着压低力的持续,吸收程度及范围扩展。停止加力后,牙根及牙周组织逐渐修复。     

微型钛钉种植体支抗压低犬上前牙过程中牙周组织骨保护素的表达

背景:在微型钛钉种植体支抗压低上前牙过程中,骨保护素可否发挥抑制骨吸收的作用,尚不十分清楚。目的:观察微型钛钉种植体支抗压低犬上前牙过程中牙周组织骨保护素的表达变化。方法:9只犬分为5组,对照组未加正畸装置,于实验开始时处死;其余各组在上颌两侧第二切牙和第三切牙牙根之间唇侧的牙槽间隔处植入微型钛钉种植体作为支抗,每侧施加100g的牵引力压低上颌两侧第一和第二切牙,分别于加力后1,2,4,12周(主动加力4周,撤力后保持8周)处死。选择一侧第一和第二切牙连同牙龈、牙槽骨完整切取,进行牙周组织内骨保护素的免疫组化染色。结果与结论:牙周组织中骨保护素的表达在加力1周后开始增加,2周达最高峰,其后开始下降,4周后回落接近正常水平。12周后(撤力8周后),骨保护素阳性细胞数量少量回升,统计结果显示与加力4周后以及未加力时差异无显著性意义。提示微型钛钉种植体支抗压低犬上前牙过程中,骨保护素参与了牙周组织的改建,并随时间的改变,呈动态变化过程。     

微型钛钉种植体支抗压低犬上前牙过程中牙周组织骨保护素的表达

背景：在微型钛钉种植体支抗压低上前牙过程中,骨保护素可否发挥抑制骨吸收的作用,尚不十分清楚。目的：观察微型钛钉种植体支抗压低犬上前牙过程中牙周组织骨保护素的表达变化。方法：9只犬分为5组,对照组未加正畸装置,于实验开始时处死;其余各组在上颌两侧第二切牙和第三切牙牙根之间唇侧的牙槽间隔处植入微型钛钉种植体作为支抗,每侧施加100g的牵引力压低上颌两侧第一和第二切牙,分别于加力后1,2,4,12周（主动加力4周,撤力后保持8周）处死。选择一侧第一和第二切牙连同牙龈、牙槽骨完整切取,进行牙周组织内骨保护素的免疫组化染色。结果与结论：牙周组织中骨保护素的表达在加力1周后开始增加,2周达最高峰,其后开始下降,4周后回落接近正常水平。12周后（撤力8周后）,骨保护素阳性细胞数量少量回升,统计结果显示与加力4周后以及未加力时差异无显著性意义。提示微型钛钉种植体支抗压低犬上前牙过程中,骨保护素参与了牙周组织的改建,并随时间的改变,呈动态变化过程。     

微型种植体支抗负载对邻近牙根及牙周组织的影响

背景：微型种植体植入过程中植入的位点和方向、微型种植体加载后的移动、牙齿移动后与微型种植体接触等都将导致牙根的损害。目的：观察微型种植体负载不同周期后与其邻近的牙根和牙周组织的变化,以及牙周组织中骨保护素的表达变化。方法：beagle犬2只,在犬上颌第2,3,4前磨牙和下颌第2,3,4前磨牙及第1磨牙的牙根之间的唇侧牙槽间隔邻近牙根处各植入1枚微型种植体。每只犬各植入微型种植体14枚,上颌6枚,下颌8枚,其中上颌有2枚微型种植体设置为对照组不加载,其余均为实验组加载正畸力。微型种植体植入后2周,通过镍钛螺旋拉簧为微型种植体加载150 g的水平力。分别于微型种植体负载4周、8周后处死beagle犬,完整切取牙齿连同牙槽骨,苏木精-伊红染色观察以及免疫组织化学法检测牙周组织中骨保护素的表达变化。结果与结论：当微型种植体邻近牙根时,牙根表面牙槽骨出现吸收陷窝;微型种植体负载与牙根相向的水平力后,牙槽骨吸收变的更加活跃。当微型种植体接触牙周膜时,牙根表面的牙骨质局部严重吸收甚至达牙本质层。微型种植体接触牙根后负载,大面积的牙骨质全层吸收,牙本质暴露在外并出现吸收。对照组骨保护素出现强阳性表达,8周表达显著;8周实验组的骨保护素阳性表达明显下降（P〈0.01）。结果表明,微型种植体邻近牙根植入后,邻近微型种植体的牙根及牙周组织均受到不同程度的损伤。微型种植体负载与牙根相向的水平正畸力,短期内对牙周组织中骨保护素的表达影响较小,随着负载周期的延长,压力显著抑制了骨保护素的表达。提示当发现邻近牙根植入后,微型种植体不应再负载与邻近牙根相向的正畸力,而应该及时取出待牙根自行修复,避免对邻近牙根的损伤进一步加重。     

比格犬自体牙移植的牙周重建研究

目的通过分析比格犬自体牙移植术前、后影像学和组织学变化,探究自体牙移植后牙周组织的再生与改建机理。方法选择1只5年龄比格犬,左侧上颌第一侧切牙进行自体牙原位移植,双侧上颌第二侧切牙交替移植,术后进行X射线检查和组织学HE染色,观察移植牙牙周愈合情况。结果术后1月肉眼见牙龈附着紧密、无松动,X射线片显示牙周愈合良好,牙周间隙缩小,根尖区域无透射影像,根管内无牙根内吸收影像;移植术后两月X射线片显示牙根尖周可见小范围低密度透射影像,无外吸收影像,根管内无牙根内吸收影像。组织学HE染色切片可见随愈合时间的增加,沟内上皮炎症细胞浸润明显下降,牙颈部结合上皮再附着逐渐紧密,牙根吸收陷窝表面可见薄层新生牙骨质,牙周膜纤维随功能改建,排列逐渐规则,硬骨板改建初期活跃,两月后形成较多成骨细胞。结论采取恰当的自体牙移植方式,牙周组织的再生是可以预期的。牙齿拔除时的机械性损伤是造成牙根吸收的重要因素,移植后及时的牙髓治疗是减少自体牙移植并发症的关键因素之一。     

减阻牵张快速牙齿移动的组织学变化

背景:采用降低牙移动路径上的骨阻力和强持续牵张力能快速移动正畸牙,缩短正畸疗程,但移动牙组织变化规律目前尚不清楚.目的:观察减阻牵张法快速移动牙齿的牙周组织学变化.方法:采用自身对照设计,以犬一侧下颌为实验侧,另一侧为对照侧,拔除下颌第二前磨牙,实验侧采用减阻牵张法,对照侧采取传统正畸方法,远移第一前磨牙.加力后2周,测量移动牙及支抗牙移动距离;加力后1,2,4,12周观察牙周膜、牙槽骨的组织学变化.结果与结论:加力后1～4周,实验侧和对照侧移动牙张力侧均表现为牙周膜增宽,成骨活跃,牙槽骨表面有新骨生成;压力侧均表现为牙周膜缩窄,破骨细胞活跃,牙槽骨有明显吸收,牙骨质也有不同程度吸收;但是,实验侧成骨细胞和破骨细胞出现均早于对照侧,牙槽骨及牙骨质吸收程度较对照侧严重.12周时,实验侧和对照侧牙周组织表现无明显差别.而加力2周,实验侧牙齿移动距离明显大于对照侧(P＜0.05).说明减阻牵张法可以快速移动牙齿;与传统正畸牙移动相比,两者牙周组织的改建只存在时间及程度的差异,不存在质的差别.     

微种植体支抗压低上颌磨牙的临床应用

6例上颌颌磨牙伸长的病例,在患侧上颌骨颊、腭侧各植入1枚微种植体,以其为支抗压低磨牙。6名患者伸长的磨牙均得到压低,平均治疗时间为6个月,平均压低约2mm,伸长磨牙经压低后未见牙根吸收,牙周情况良好。利用微种植体支抗技术压低伸长磨牙,患者易于配合,治疗时间短,疗效较明显。     

上颌第一磨牙弯曲牙根生物组织应力的三维有限元分析

背景：根据弯根牙牙周膜应力分布为口腔临床工作者提供正畸施力的方式和大小,以此来优化正畸力系统设计。目的：探讨上颌第一磨牙弯曲牙根受到正畸力作用下牙根及牙周膜的应力分布情况。方法：选用正常形态和牙根弯曲的上颌第一磨牙作为建模素材,应用 CT 机扫描,ANSYS Workbench 11.0 有限元分析软件建立上颌第一磨牙及其牙周膜的有限元模型,应用 6 种不同载荷方式对模型进行加载,分析其应力分布情况。结果与结论：弯根牙应力集中区主要在牙颈部,其次是根尖部,牙齿在做整体移动时其牙根、牙周膜、牙槽骨应力最小。对于弯根牙的矫治需要更准确的定位以及更合理的牵引力。     

不同加载方式压低上前牙时初始应力在牙体、牙周膜及牙槽骨分布的三维有限元分析(英文)

背景:探索最佳的既能有效地压低前牙,又不造成牙齿损伤的加载力值尤为重要。目的:模拟在上颌侧切牙和尖牙间使用种植支抗对上颌前牙施加压入力时的受力状况,探讨临床上最佳的加载力值及施力方向。方法:建立上颌前牙段牙齿-牙周膜-矫治系统的三维有限元模型,分析上前牙在不同压低力值及施力方向时牙体、牙周膜及牙槽骨初始应力的分布情况。结果与结论:同时压低6个上前牙的最佳力值范围在0.5～1.0 N。应力峰值集中区域位于侧切牙的远中颈缘;当施力方向为腭向20°时,牙周膜应力分布相对均匀。即在侧切牙和尖牙间唇侧使用种植钉时,加载0.5～1.0 N力的同时配合适当的远中方向牵引力,可对均角型患者达到将上颌前牙整体真性压入的效果,是一种最佳的矫治力系统。     

尼古丁对大鼠实验性牙移动牙根吸收的影响

背景：吸烟严重影响牙周组织及牙根的健康,烟草中的尼古丁会加速牙周病患者牙周组织的破坏,影响骨改建,引起骨吸收.而整合素αvβ3参与正畸牙移动过程中的牙根吸收.目的：以整合素αvβ3在破牙骨质细胞的表达量为主要观察指标,初步探讨尼古丁对正畸牙移动牙根吸收的影响.方法：将110只实验SD大鼠随机分为空白对照组、生理盐水组以及0.5 mg/kg尼古丁组、0.75 mg/kg尼古丁组、1 mg/kg尼古丁组.后4组上颌第一磨牙施加50 g近中向拉力,同时每日向各组的大鼠腹腔注射一定剂量的尼古丁酒石酸溶液或生理盐水,运用苏木精-伊红染色和免疫组织化学染色,观察各组大鼠上颌第一磨牙加力1,3,5,7,14 d的组织变化情况和整合素αvβ3的表达量.结果与结论：随着加力时间的延长的,牙根周围的牙周膜纤维变形,排列紊乱,炎性细胞浸润,压力侧、张力侧以及根分叉处牙根表面开始出现吸收陷窝、破牙骨质细胞.尼古丁注射的剂量越大,牙根表面的吸收陷窝越多越深,破牙骨质细胞显著增加.免疫组化染色结果显示,除空白对照组外,整合素αvβ3在各个实验组的破牙骨质细胞中表达,并且随着加力时间的延长,其表达强度增强,加力7 d时呈现强阳性表达,加力达到14 d时,表达随之减弱.随着尼古丁注射剂量的增加,整合素αvβ3阳性表达的破牙骨质细胞逐渐增加.结果说明,尼古丁会加重正畸牙移动过程中的牙根吸收,并且可能具有时间依赖性以及剂量依赖性.     

Management of internal root resorption in the maxillary central incisor with fractured root using Biodentine

Biodentine is desirable to successfully manage internal root resorption, and the MTA apical plug backfilled with thermoplasticized gutta‐percha is suggested for the tooth with external apical root resorption.     

Effect of Low-Intensity Pulsed Ultrasound on Orthodontically Induced Root Resorption in Beagle Dogs

We investigated the effect of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced inflammatory root resorption in vivo. Ten beagle dogs were treated with an orthodontic appliance to move the mandibular fourth premolars bodily. The orthodontic movement was carried out for 4 wk with a continuous force of 1 N/side; using a split-mouth model, LIPUS was applied daily for 20 min. Fourth premolar and surrounding periodontal tissue were evaluated with micro-computed tomography and hematoxylin and eosin and tartrate-resistant acid phosphatase staining. We calculated the number, volume and distribution of root resorption lacunae and their percentage relative to total root volume, orthodontic tooth movement and periodontal ligament space. There was no significant difference in orthodontic tooth movement between the two sides. LIPUS significantly reduced the number of orthodontically induced inflammatory root resorption initiation areas by 71%, reduced their total volume by 68% and reduced their volume relative to the affected root total volume by 70%. LIPUS induced the formation of a precementum layer, thicker cementum and reparative cellular cementum.     

年轻恒牙外伤脱位的临床固定方法

年轻恒牙由于牙根尚未发育完成,牙周组织疏松,外伤时容易发生亚脱位、部分脱出、侧方脱出、挫入及全脱出,正确的临床复位固定是保证外伤年轻恒牙治疗成功的关键。本文就目前儿童口腔临床常用的年轻恒牙外伤脱位后的固定方法作一综述。     

Non-Invasive management of invasive cervical resorption associated with periodontal pocket: A case report

BACKGROUND Invasive cervical resorption(ICR), a commonly misdiagnosed condition, is an aggressive form of external tooth resorption that contributes to periodontal tissue inflammation and deepening of the periodontal pockets. Herein we report the case of a patient, exhibiting ICR and elaborate the effects of a non-surgical approach in the amelioration of this condition.CASE SUMMARY A 21-year-old female reporting intermittent pain at the upper left side, multiple restorations, no trauma history, and having received orthodontic treatment was studied. Localized erythematous swelling was noted at the buccal interdental papilla between the left maxillary first molar and second premolar. The diseased pulp and tissue in resorption were removed and the root canal system including the defect were sealed using gutta percha/AH Plus and mineral trioxide aggregate(MTA). At the one-year recall, the tooth showed no symptoms and responded normally to percussion and palpation. The surrounding periodontium exhibited a normal color and the probing depth was normal. Radiographic examination showed a restoration of crestal alveolar bone and good adaption to MTA.CONCLUSION Non-surgical root canal treatment in conjunction with resorption defect orthograde repair with MTA was found to be an effective treatment option in the elimination of ICR. Early diagnoses are recommended in order to employ nonsurgical approaches for management of ICR instead of surgical interventions.     

Fate of root shell after pontic/socket shield techniques,is it better to extract the whole tooth?

A series of changes occur in the remaining alveolar process after whole tooth extraction. The basic question is, why do the bony walls (especially the labial/buccal) get resorbed immediately after the tooth is removed? This could be because, with cementum of the concerned tooth and its periodontal ligament, the supporting bundle bone is dependent on the presence of the tooth. This loss can be compensated using numerous techniques, such as socket grafting using various biomaterials to preserve the alveolar bone and buccal grafting with guided tissue regeneration to increase the thickness of buccal bone or placement of implant immediately. However, none of these techniques prevent the modelling of the alveolar bone post-extraction. Few studies have demonstrated that preservation of the roots in the alveolar process maintains the bone volume and facilitates vertical bone growth. A histological study in animals and humans has shown that the retained root shell does not pose any interference in the osseointegration of the implant (if placed simultaneously). Although various names have been proposed to describe the concept of retaining full or part of the root to prevent the resorption of the ridge, socket-shield and pontic-shield are the two most commonly used terms worldwide. The extraction of the whole tooth might be the choice of therapy when socket-shield or pontic-shield is not possible due to anatomical variations, infections, or lack of clinical expertise. Irrespective of the size, when a whole root or a root fragment (is left in situ), it is the dentist’s ethical duty to advise/inform the patient and ensure repeated clinical and radiographic follow-up. The present study aimed to highlight the current status of these techniques, their benefits, and possible complications and address whether the paradigm of the teeth extraction methods should be altered.     

Gallium diffusion in human root dentin: quantitative measurements by pulsed Nd:YAG laser ablation combined with an inductively coupled plasma mass spectrometer

OBJECTIVE: The purpose of this work was to determine if gallium nitrate placed in human root canals would diffuse across root dentin and reach concentrations high enough to inhibit osteoclasts (approximately 10(-4) M). BACKGROUND DATA: External root resorption by osteoclasts is a common sequela of dental trauma. If not detected and treated, it can lead to the loss of a tooth. Gallium has recently been reported to inhibit osteoclastic resorption in vitro. METHODS: Roots were cleaned and shaped using standard endodontic procedures and the tips sealed with cyanoacrylate cement. The root canal space was filled with an aqueous solution of 1.0 M gallium nitrate chelated with 1.0 M sodium citrate buffer (pH 7.2). The roots were then sectioned longitudinally into two equal halves. Each half was fixed to a translation stage that moved at a constant rate beneath a frequency-quadrupled Nd-YAG laser (266 nm) laser that was used to sample the concentration of 43Ca, 69Ga, and 71Ga by laser ablation across the thickness of root dentin to the periodontal surface. The plume of ablated dentin was swept into an inductively heated plasma chamber by argon gas and hence into a mass spectrometer. RESULTS: Quantitative analyses of the distribution of gallium showed it was highest adjacent to the root canal space and fell as more peripheral sites were sampled but then rose slightly at the external boundary of the root which is covered with a thin layer of atubular cementum. CONCLUSIONS: Even the lowest concentrations of gallium found in peripheral root dentin exceeded the 10(-4) M concentration required to inhibit osteoclastic activity. This simple endodontic treatment should undergo clinical trials to determine its efficacy in vivo. The laser ablation, inductively coupled mass spectrometry method is a powerful analytic tool for measuring spatial distribution of materials in mineralized tissues.     

骨桥蛋白介导机械压力引起的骨吸收

学术背景: 拔牙后, 剩余牙槽嵴的吸收是一个复杂的过程, 压力是引起其吸收的主要原因之一。近年来的研究表明骨桥蛋白是一种压力敏感因子。目的: 从骨桥蛋白入手综述在机械压力改变引起骨吸收情况下, 骨桥蛋白的作用; 骨桥蛋白与骨改建之间的关系、骨桥蛋白与细胞表面受体的作用机制及骨桥蛋白与成骨细胞和破骨细胞之间的关系。揭示应力引起牙槽骨吸收的分子机制, 为临床对剩余牙槽嵴吸收进行分子、基因治疗提供理论依据。检索策略: 应用计算机检索 Pubmed 数据库 1985- 01/2007- 06 的相关文献,检索词为 OPN、mechanical stress、bone resorption, 限制语言种类为 English, 同时检索中文期刊全文数据库 1995- 01/2007- 06 的相关文献, 检索词为: 骨桥蛋白、机械压力、骨吸收。共检索到 52 篇文章, 对资料进行初审, 纳入标准: 与研究骨桥蛋白与机械压力引起的骨吸收改建密切相关。排除标准: 重复研究。文献评价: 计算机初检得到 52 篇文献, 6 篇中文, 46 篇英文。阅读标题和摘要进行初筛, 排除因研究目的与此文无关的 5 篇, 内容重复性的研究 13 篇, 共保留 34 篇文献做进一步分析。所选用的 34 篇文献中主要是研究骨桥蛋白在与机械压力引起的骨吸收改建中作用方面的文章, 其中 6 篇为综述 \ 述评,其余均为临床或基础实验研究。资料综合: ①骨桥蛋白广泛分布于人体组织, 并行使多种生理功能, 近来发现骨桥蛋白是一种机械敏感因子。②骨组织是一种特殊的生物组织,它在失去机械压力刺激(废用性萎缩)和存在机械压力刺激的情况下都能发生骨吸收和骨改建。③骨吸收可以看做机械压力造成的系列分子事件的结果, 骨桥蛋白作为一种主要的蛋白参与骨吸收与骨改建这两种过程。④骨桥蛋白可作为一种趋化因子引致前体破骨细胞迁移到骨表面,并介导与破骨细胞表面整合素的结合而增强骨吸收, 是一种由于机械压力引起的骨丧失的必需分子。⑤骨桥蛋白在成骨细胞与破骨细胞间起信号传导作用。⑥骨桥蛋白可以作为骨形态发生蛋白 2 长期作用的反馈抑制信号而抑制骨的矿化。结论: 骨桥蛋白是压力敏感因子, 在压力刺激引起的骨吸收中起介导作用。     

抗生素药物对感染根管作用的研究

目的:探讨抗生素药物用作感染根管消毒剂的效果。方法:通过临床90例患者的对照观察,X线片以及实验细菌学检验,对罗红霉素与甲硝唑等抗生素类混合糊剂用于感染根管与常规使用的甲醛甲酚(FC),樟脑酚(CP)作对比,比较三种消毒剂前后根管内的细菌变化以及治疗后的反应。结果:罗红霉素与甲硝唑等抗生素类药物混合糊剂对感染根管有很强的杀菌作用,根管治愈成功率达90.25%,优于樟脑酚(70.25%)及甲醛甲酚(70%),对根管周组织无刺激性及副作用,临床效果肯定。结论:罗红霉素与甲硝唑等抗生素混合糊剂是有效而理想的感染根管的消毒药物。