正畸力对牙髓的影响

正畸治疗的基础在于临床上熟知正畸力对患者机体的影响和正确运用生物力学原则。正畸力对牙髓和牙周组织的影响越来越受到口腔医师的关注。牙髓因其特殊的解剖生理特点,在正畸治疗中更应受到重视,本文就正畸力对牙髓的影响进行综述。     

正畸施力初始(24小时)牙髓中神经肽P物质变化的实验研究

本实验采用免疫组织化学ABC法，结合显微图像定量分析，检测对猫尖牙施加正畸力24小时内牙髓中P物质（SubstanceP，SP）量的变化。结果得出：施力后24小时内SP释放量逐渐增加。显微图像分析结果经统计学处理，每组间差异均非常显著（P＜0.01）。以上结果提示；牙髓中SP的增加可能是正畸治疗初期出现牙齿轻微疼痛不适症状的原因之一。对此，可用牙髓血流调控的体液调节机理来解释。     

正畸治疗过程中引起的牙髓变化

随着口腔证畸研究和临床实践的不断深入，对于错（牙合）畸形的矫治，无论在理论基础还是临床应用方面都取得长足发展。虽然正畸治疗带来的益处不言而喻，但其附加的影响同样值得关注，其中之一即为牙髓反应。大量研究表明，适宜的正畸力不会造成牙髓的病理性损害[1]，     

牙髓诊断试验的临床应用

在牙体牙髓和根尖周疾病的诊治中．准确判断牙髓状态非常重要．它直接关系到对疾病的正确诊断、合理的治疗设计及对预后的准确估计。临床工作中对牙髓实施的冷测、热测和电测是将温度刺激或电刺激施加于牙齿硬组织上,牙髓组织中的A6神经纤维接受到刺激后会作出相应的反应．产生不同程度的痛感．据此．医生对牙髓状态做出判断。但此时患牙的反应仅指示其神经纤维的功能强度,并不能提供牙髓血流的信息．因此不能反映出牙髓的病理状态。近年来．发展出一些测定牙髓血供状态的新诊断方法．如激光多普勒血流测定仪、脉搏血氧饱和度测试仪．这些测试方法的结果更能真实地反映牙髓的病理状态．但仍需结合病史、临床检查、X线片检查来综合判断牙髓状况。本文通过回顾牙髓诊断试验的文献,对各种方法的原理．临床应用、可靠性及安全性进行综述．旨在为临床实践提供有益的参考。     

牙髓活力检测的新进展

牙髓状态的判定对牙体修复和牙髓治疗方案的选择十分重要,目前临床上牙髓状态的检测大致分为牙髓感觉测试和牙髓活力测试.牙髓感觉测试通过刺激牙髓神经观察患者的主观感受来判断,主观性较强,不一定能反映牙髓的真正状态,而牙髓活力检测可以通过检测牙髓血流量的变化从而体现牙髓的活力,客观、无创,在临床应用上有一定的优势.本文就牙髓感觉测试与牙髓活力检测的区别,以及目前牙髓活力检测的研究新进展作一综述.     

人牙髓细胞的体外培养

对牙髓细胞的体外培养是研究牙髓的有效工具。随着细胞培养技术的发展,牙髓细胞培养的成功率不断提高。干细胞生物学的研究使得人们认识到,在成体组织中也存在干细胞。目前不仅已分离出牙髓干细胞,而且对其干细胞特征作了进一步的研究,这将给牙髓病治疗和牙齿组织工程带来重大的变化。     

牙髓再生技术应用于成熟恒牙的挑战及应对策略

牙髓再生技术是近年来的研究热点,也是根管治疗的良好替代治疗手段。目前对于牙髓再生的研究主要集中在年轻恒牙,而实际上需要接受牙髓治疗的成熟恒牙远多于年轻恒牙,因此牙髓再生技术应用于成熟恒牙有巨大的应用前景。相比年轻恒牙,成熟恒牙的根尖孔已发育完全、解剖结构多样、微环境复杂,牙髓再生难以实现。本文对成熟恒牙在牙髓再生中的根管预备、根管感染控制、干细胞来源及生长因子及支架的应用面临的困难及应对策略作一综述,为成熟恒牙牙髓再生技术的应用提供参考。     

牙髓组织增龄变化的组织学定量研究

采用组织学定量方法及组化与免疫组化手段,对各年龄组的各类牙齿进行研究,进一步了解到牙髓组织各成分的老化过程,其中牙髓细胞随年龄而递减的趋势十分明显,它的变化及组织退变可能是牙髓老化的标志。     

基因芯片技术在牙髓生物学研究中的应用进展

基因芯片作为一种高通量、快速和平行核酸序列测定及定量分析技术已经广泛地应用于分子生物学领域。牙髓基因组学的研究将有利于加强人们对牙髓生理和病理机制的认识,从而最终应用于临床预防、诊断和治疗等,因此,本文就基因芯片技术及其与牙髓干细胞相关的基因、牙髓老龄化改变相关的基因和龋病时牙髓相关的基因等研究进展作一综述。     

再生性牙髓治疗方法的前景

再生性牙髓治疗是基于生物学基础治疗的一种方法,目的是替换受损的部分牙髓组织或允许牙髓样组织形成以完全替代原牙髓组织。针对牙髓炎或牙髓坏死的年轻恒牙的治疗,研究者们利用口腔来源干细胞或根尖周组织的干细胞建立各种利于修复的微环境,提出了如牙髓血运重建术/干细胞归巢治疗等充满前景的新治疗技术,从而为牙髓的再生提供了大量研究资料及可选治疗手段。该文对再生性牙髓治疗方法的现状及其发展前景作一综述。     

Effect of orthodontic force on dental pulp histomorphology and tissue factor expression:: A systematic review

ObjectivesTo evaluate the effects of orthodontic force on histomorphology and tissue factor expression in the dental pulp.Materials and MethodsTwo reviewers comprehensively and systematically searched the literature in the following databases: Latin American and Caribbean Health Sciences, Embase, Cochrane, PubMed, Scopus, Web of Science, and Grey literature (Google Scholar, OpenGrey, and ProQuest) up to September 2020. According to the Population, Intervention, Comparison, Outcomes, Studies criteria, randomized clinical trials (RCTs) and observational studies that evaluated the effects of orthodontic force on dental pulp were included. Case series/reports, laboratory-based or animal studies, reviews, and studies that did not investigate the association between orthodontic force and pulpal changes were excluded. Newcastle-Ottawa Scale and Cochrane risk-of-bias tool were used to assess the risk of bias. The overall certainty level was evaluated with the Grading of Recommendations Assessment, Development and Evaluation tool.Results26 observational studies and five RCTs were included. A detailed qualitative analysis of articles showed a wide range of samples and applied methodologies concerning impact of orthodontic force on the dental pulp. The application of orthodontic force seems to promote several pulpal histomorphological changes, including tissue architecture, cell pattern, angiogenesis, hard tissue deposition, inflammation, and alteration of the expression levels of 14 tissue factors.ConclusionsAlthough the included articles suggest that orthodontic forces may promote histomorphological changes in the dental pulp, due to the very low-level of evidence obtained, there could be no well-supported conclusion that these effects are actually due to orthodontic movement. Further studies with larger samples and improved methods are needed to support more robust conclusions.     

The effect of orthodontic forces on calcitonin gene-related peptide expression in human dental pulp

Introduction

The purpose of this study was to quantify the effect of moderate and severe orthodontic forces on calcitonin gene-related peptide (CGRP) expression in healthy human dental pulp.

Methods

Thirty human dental pulp samples were obtained from healthy premolars in which extraction was indicated for orthodontic reasons. Before extraction, teeth were divided into 3 groups of 10 premolars each: (1) the control group: healthy premolars without application of orthodontic forces; (2) the moderate force group: a 56-g force was applied to the premolars for 24 hours; and (3) the severe force group: a 224-g force was applied to the premolars for 24 hours. All dental pulp samples were processed, and CGRP was measured by radioimmunoassay.

Results

Greater CGRP expression was found in the severe force group followed by the moderate force group. The lower CGRP values were for the control group. The Kruskal-Wallis test showed statistically significant differences between groups (P < .0001). Least significant difference (LSD) post hoc tests showed statistically significant differences in CGRP expression between the control group and the severe force group (P < .0001) but not with the moderate force group (P = .06). Differences between the moderate and severe force groups were statistically significant (P < .0001).

Conclusions

CGRP expression in human dental pulp increases when teeth are submitted to severe orthodontic forces.     

矫治力初期牙髓组织HSP70表达及临床意义

目的 观察在矫治力初期牙髓组织中heat shock protein 70(HSP70)的分布及表达,探讨适宜的矫治力对牙髓组织的影响并正确运用生物力学原则。方法 16例采用拔除上颌双侧第一前磨牙进行固定矫治的患者,随机分为正常对照组,加力（0.5 N）1、3、7 d组在受力相应时段拔除,并制备石蜡标本。免疫组织化学法(SABC)观察牙髓中HSP70的表达及分布。结果 HSP70的阳性反应产物呈深褐色均质性沉淀,主要在血管内皮细胞,成牙本质细胞胞质周围呈颗粒状阳性表达。在加力1 d组HSP70的表达并没有明显增强(P>0.05),3天组表达达高峰尤其是在血管内皮细胞中(P<0.01),到7天后牙髓细胞的整体表达呈弱阳性。所有病例无一例牙髓坏死。结论 在牙移动过程中牙髓组织中HSP70的表达先升高后又逐渐减低至恢复正常水平,提示HSP70在牙移动过程中对牙髓组织的改建过程可能起着重要作用;适宜的矫治力作用下产生的HSP70可能对牙髓组织提供了有效的保护。     

Association between Orthodontic Force and Dental Pulp Changes: A Systematic Review of Clinical and Radiographic Outcomes

IntroductionOrthodontic force triggers a sequence of biological responses that can affect dental pulp. The aim of this study was to systematically evaluate the clinical and radiographic findings of orthodontic force application on dental pulp.MethodsTwo reviewers comprehensively and systematically searched 6 electronic databases (Latin American and Caribbean Health Sciences [LILACS], Embase, Cochrane Library, MEDLINE/PubMed, Scopus, and Web of Science) and the gray literature (Google Scholar, OpenGrey, and ProQuest) until April 2021. According to the PICOS criteria, randomized clinical trials and observational studies that evaluated clinical or radiographic findings compatible with dental pulp changes due to orthodontic force were included. Studies in open apex or traumatized teeth, case series or reports, and laboratory-based or animal studies were excluded. The Newcastle-Ottawa Scale and Cochrane Risk of Bias 2.0 tool were used to determine the risk of bias assessment. The overall certainty level was evaluated with the Grading of Recommendations, Assessment, Development and Evaluations tool.ResultsTwenty-six studies were included. Among the clinical findings, orthodontic force promoted an increased pulp sensibility response and decreased pulp blood flow. Changes in pulp cavity volume and increased incidence of pulp stones were the radiographic findings observed. The studies presented a moderate risk of bias for most of the domains. The certainty of the evidence was considered very low.ConclusionsOrthodontic force promoted changes in the dental pulp, generating clinical and radiographic findings. It is crucial to know these changes so that orthodontic mechanics can be safely performed. The clinician has effective noninvasive methods to assess the health and possible pulp changes during orthodontic treatment.     

牙髓细胞的原代培养方法探讨:冠部和根部牙髓的比较

目的 比较并建立冠部和根部牙髓细胞培养的理想方法一方法：自年轻、健康的人牙中取出完整牙髓，分别应用组织块法和组织块酶解法(0.1％I型胶原酶)对冠、根部牙髓进行原代细胞培养，通过对细胞培养成功率、细胞贴壁率和细胞活性的评估，确定用于根、冠髓细胞培养的理想方法一结果：组织块法比组织块酶解法具有较高的成功率．游出细胞具有较高的生长活性和较低的贴壁率.结论 在对根、冠髓细胞的原代培养中，组织块法优于组织块酶解法。本实验建立了冠、根部牙髓细胞原代培养的理想方法.     

Orthodontic treatment mediates dental pulp microenvironment via IL17A

ObjectiveOrthodontic treatment induces dental tissue remodeling; however, dental pulp stem cell (DPSC)-mediated pulp micro-environmental alteration is still largely uncharacterized. In the present study, we identified elevated interleukin-17A (IL17A) in the dental pulp, which induced the osteogenesis of DPSCs after orthodontic force loading.DesignTooth movement animal models were established in Sprague-Dawley rats, and samples were harvested at 1, 4, 7, 14, and 21 days after orthodontic treatment loading. DPSC self-renewal and differentiation at different time points were examined, as well as the alteration of the microenvironment of dental pulp tissue by histological analysis and the systemic serum IL17A expression level by an ELISA assay. In vitro recombinant IL17A treatment was used to confirm the effect of IL17A on the enhancement of DPSC self-renewal and differentiation.ResultsOrthodontic treatment altered the dental pulp microenvironment by activation of the pro-inflammatory cytokine IL17A in vivo. Orthodontic loading significantly promoted the self-renewal and differentiation of DPSCs. Inflammation and elevated IL17A secretion occurred in the dental pulp during orthodontic tooth movement. Moreover, in vitro recombinant IL17A treatment mimicked the enhancement of the self-renewal and differentiation of DPSCs.ConclusionsOrthodontic treatment enhanced the differentiation and self-renewal of DPSCs, mediated by orthodontic-induced inflammation and subsequent elevation of IL17A level in the dental pulp microenvironment.     

MMP-3诱导人牙髓成纤维细胞CCN2mRNA的表达及意义

目的：通过观察基质金属蛋白酶-3（MMP-3）对体外培养人牙髓成纤维细胞中结缔组织生长因子（CTGF/CCN2）mRNA的影响,揭示MMP-3促进牙髓损伤愈合的机制。方法：选取年轻患者因正畸或阻生拔除的健康第三磨牙,取出牙髓以常规体外酶消化培养法获得人牙髓成纤维细胞,利用RT-PCR方法检测经MMP-3诱导30min后人牙髓成纤维细胞中CCN2mRNA的表达。结果：正常组和实验组人牙髓成纤维细胞均有CCN2mRNA表达,但是经MMP-3诱导后的人牙髓成纤维细胞CCN2mRNA的表达更强。结论：MMP-3通过诱导CCN2mRNA的合成,从而促进牙髓损伤的愈合。     

大鼠正畸牙移动中牙髓iNOS表达的免疫组化研究

目的:建立大鼠正畸牙移动模型,观察牙髓组织中诱导型一氧化氮合酶(iNOS)的表达及分布,探讨正畸牙移动过程中牙髓改建的分子机制。方法:采用免疫组织化学方法对正畸加力后12h、1d、3d、7d和14d大鼠牙髓组织中iNOS进行检测,观察iNOS的时空分布。结果:iNOS阳性反应的产物呈深褐色均质沉淀,主要在血管内皮细胞、成牙本质细胞胞浆核周区颗粒状阳性表达。这种染色在正畸加力后12h、1d、3d天有不同程度的增强,3d达到高峰,加力后7d和14d表达减弱,第14d与对照组无明显差异。结论:正畸牙移动过程中牙髓组织iNOS的表达先升高后逐渐恢复正常,提示iNOS可能在正畸牙移动牙髓组织改建过程中起重要作用。