再生性牙髓治疗后新组织形成研究进展

对于牙髓感染或坏死且根尖孔未闭合的年轻恒牙,采用再生性牙髓治疗,不仅能使根尖孔闭合,还能使牙根延长,根管壁增厚,从而减少患牙远期根折的风险。动物实验和临床研究都表明,再生性牙髓治疗后形成了新组织。本文就再生性牙髓治疗后新组织形成的研究进展做一综述。     

牙髓血运重建术后根管内矿化组织形成的研究进展

牙髓血运重建术是治疗年轻恒牙牙髓炎和根尖周病的方法之一,术后根管内矿化组织的形成有助于根管壁增厚、促进根尖孔闭合及根尖正常发育。近年来,学者们对根管内矿化组织开展了大量研究。该文就近年来牙髓血运重建术后根管内矿化组织形成的基础和临床研究作一综述,对牙髓血运重建过程中矿化组织的组成、形成机制及其影响因素进行分析,并提出促进牙髓血运重建术后根管内矿化组织形成的临床决策。     

再生性牙髓治疗成功的影响因素分析

再生性牙髓治疗可以作为治疗年轻恒牙牙髓坏死的首选治疗方案,其原理是通过细胞归巢作用实现组织修复和牙髓再生,具有促进牙根继续发育、根尖孔闭合以及根管壁增厚的优点。目前再生性牙髓治疗已经实现初步临床应用,并取得了良好的疗效,但缺乏统一的临床疗效评估手段和影响其成功的因素分析。本文就再生性牙髓治疗的评判标准和影响其成功的因素进行综述。     

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。     

年轻恒牙牙髓坏死的血管再生治疗

牙髓血管再生是对感染根管充分消毒,用光滑髓针刺破根尖周组织形成凝血块,将其作为组织再生的基质,同时进行严密的冠部封闭,使感染坏死的年轻恒牙根管壁增厚和牙根继续发育,根尖孔闭合,增强牙根的抗折力。在不久的将来,牙髓血管再生有可能成为年轻恒牙牙髓坏死的首选治疗方法。本文针对年轻恒牙的特点就其在年轻恒牙牙髓坏死的治疗作一综述。     

畸形中央尖折断所致年轻恒前磨牙根尖周炎再生性牙髓治疗效果观察

目的    观察对畸形中央尖折断所致的年轻恒牙根尖周炎进行再生性牙髓治疗的临床疗效。方法    选择2014年3月至2015年9月大连市口腔医院儿童口腔科因畸形中央尖折断引起的年轻恒前磨牙急、慢性根尖周炎的10 ~ 13岁患儿10例,共11颗前磨牙,经彻底控制炎症后行再生性牙髓治疗。定期随访观察,结合影像学检查,与术前进行对比,评价根尖周病变的愈合状况及牙根发育情况。结果    1颗患牙因引血入根管失败而放弃再生性牙髓治疗,改行根尖诱导成形术。其余10颗均实施再生性牙髓治疗,术后观察10 ~ 23个月,根尖周炎症状均消失,牙根变长,根管壁增厚,根尖聚拢,获得较好疗效。2例出现髓腔部分钙化现象。结论    对年轻恒牙根尖周炎进行再生性牙髓治疗较传统的根尖诱导成形术具有不可比拟的优势。     

牙髓血管再生治疗牙髓坏死伴根尖周病变的年轻恒牙的两年疗效观察

目的:观察牙髓血管再生治疗对牙髓坏死伴根尖周病变的年轻恒牙的临床疗效.方法:选取12例9～13岁患者的12颗诊断为牙髓坏死伴根尖周炎的年轻恒牙进行牙髓血管再生治疗.术后定期进行临床和影像学复查.结果:术后复查期21～24个月、12例全部治愈.观察到4种类型的愈合方式:①根管长度和厚度增加,根尖孔闭合;②MTA下方根管弥漫性钙化;③MTA下方部分根管钙化;④根尖周病变愈合但根尖孔未闭合.结论:牙髓血管再生治疗能够促进牙髓坏死伴根尖周病变的年轻恒牙的牙根继续发育,但治疗后并不都表现为牙根的继续发育,硬组织在根管壁上的过度沉积可能会导致根管钙化.     

再生性牙髓治疗的研究进展

再生性牙髓治疗以牙髓生物学为基础,运用组织工程的基本原则,促进牙髓-牙本质复合体功能性再生,在牙髓坏死或伴根尖周炎的年轻恒牙治疗中已取得良好疗效,近年来也逐渐尝试应用于根尖发育成熟的恒牙治疗。最大限度控制感染并促进组织修复再生是再生性牙髓治疗的关键所在。与年轻恒牙的治疗不同,在根尖发育成熟的恒牙中可适当行根管机械预备;根管冲洗和根管消毒剂的选择,需综合考量抗菌效果、生物安全性及可能引起的牙冠变色、根管钙化等并发症;生物陶瓷材料的发展为冠方封闭材料提供了更多选择,但需进一步临床评估。除传统的血凝块支架外,以富血小板血浆、富血小板纤维蛋白、浓缩生长因子等血小板浓缩制品为代表的新型组织支架不断涌现,其实际临床疗效及与血凝块联用疗效仍需长期、大样本的研究。     

犬年轻恒牙根尖周炎和再生性牙髓治疗后组织学观察

目的    应用比格犬制造年轻恒牙根尖周炎动物模型,并进行再生性牙髓治疗（regenerative endodontic treatment, RET）,组织学观察治疗后牙根发育情况,为进一步探寻炎症与损伤修复的关系以及RET后组织修复的机制奠定实验基础。方法    本研究于2013年12月至2014年7月在中国医科大学口腔医学院中心实验室完成。选择3只6月龄的比格犬,每只犬双根前磨牙4颗,共12颗牙,随机分为正常对照组、根尖周炎组、空根管组以及RET组,每组3颗牙。RET后3个月全麻下处死实验动物,颈静脉灌流固定,将上下颌骨取下后固定1周,pH 7.2的10%乙二胺四乙酸中脱钙3个月。常规脱水,石蜡包埋,切片,HE染色,镜下观察。结果    根尖周炎组根管内可见大量免疫细胞,无新组织修复;空根管组根管内仅有纤维性修复;RET组根管内、根管壁以及根尖部有新组织形成,使根管壁增厚,牙根增长,根尖孔闭合,牙根继续发育。结论    在有效根管消毒、控制年轻恒牙根尖周炎的基础上,机体即能发挥一定限度的组织修复能力;RET过程中刺破出血本身造成局部适度的损伤,可能进一步激发了干细胞的增殖和分化,利于新组织的形成,使牙根继续发育。     

年轻恒牙牙髓再生性治疗的研究进展

个体患牙髓病或根尖周病后,年轻恒牙牙根的继续生长发育受阻,因此,如何保证患牙根尖的正常形成和继续生长发育对口腔医生而言极具挑战。近年来报道的牙髓再生治疗病例,其利用根管内残余牙髓组织、根尖周或牙周组织中干细胞的再生分化能力,在合适的条件诱导下再生出新的高度血管化并富含结缔组织的活髓,促使牙根继续生长发育,牙根长度增加、根管壁增厚、根尖孔缩窄闭合,而且临床检查和影像学辅助检查的结果均较理想,这具有划时代的意义。牙髓再生基于组织工程学,以达到用新生牙髓组织代替原有病变牙髓组织目的。其包括两种理念：一是牙髓血运重建,诱导根尖部干细胞迁移和分化,在患牙根管内新生出有活力的牙髓样组织,完成牙根继续生长发育;二是运用组织工程技术,将具有增殖分化潜能的干细胞和适宜的生物活性支架物质置入患牙根管内,在一定的生长因子诱导下,产生新的牙本质牙髓复合体（den?tin?pulp complex,DPC）,实现牙髓再生。笔者就这两部分的研究进展作一阐述。     

Periapical tissues microvessels reactivity study after pulp extirpation and on different stages of endodontic treatment

Reaction of the microvessels in the gingival periapical tissues on pulp extirpation was followed by hyperemia development in microcirculatory bed, its expression increased in proportion as parodontal inflammation intensified and further strengthened after root canal filling. Microcirculation normalization in the gingival periapical tissues after endodontic treatment of chronic pulpitis and pulp extirpation as part of endodontic treatment was evident in 1 month in intact parodontium and in 6 months in case of its inflammation.     

Endodontic surgery (apicoectomy)--success rate of more than 90% using dental operating microscope and ultrasonic tips

The main cause of root canal treatment failure is presence of bacteria in the root canal. Surgical endodontic retreatment is indicated as a valuable treatment choice for failed endodontic treatment. The aim of the article is to describe the advantages of a new technique for apicoectomy using dental operating microscope and ultrasonic tips in comparison to the traditional technique. Precise root end resection with minimal or no bevel and accurate preparation of the root end cavity to the depth of 3-4 mm allows minimal bone removal and reduces procedural accidents such as perforation of the lingual canal wall. Zink oxide eugenol based materials allow sealing of the retrograde preparation adequately to prevent bacteria and toxins to penetrate the periradicular tissues. Literature review demonstrates success rate to above 90% when employing dental operating microscope and ultrasonic tips for retrograde cavity preparation.     

Treatment of a Large Cystlike Inflammatory Periapical Lesion Associated with Mature Necrotic Teeth Using Regenerative Endodontic Therapy

Introduction

Regenerative endodontic therapy is currently used to treat immature permanent teeth with necrotic pulp and/or apical periodontitis. However, mature teeth with necrotic pulp and apical periodontitis have also been treated using regenerative endodontic therapy. The treatment resulted in resolution of apical periodontitis, regression of clinical signs and symptoms but no apparent thickening of the canal walls, and/or continued root development. A recent study in an animal model showed that the tissues formed in the canals of mature teeth with apical periodontitis after regenerative endodontic therapy were cementumlike, bonelike, and periodontal ligament–like tissue with numerous blood vessels. These tissues are similar to the tissues observed in immature permanent teeth with apical periodontitis after regenerative endodontic therapy.

Methods

A 23-year-old woman had a history of traumatic injury to her upper anterior teeth when she was 8 years old. Subsequently, #8 developed pulp necrosis and an acute apical abscess and #7 symptomatic apical periodontitis. The apex of #8 was slightly open, and the apex of #7 was completely formed. Instead of nonsurgical root canal therapy, regenerative endodontic therapy was attempted, including complete chemomechanical debridement on #8 and #7. This was based on the premise that filling of disinfected root canals with the host's biological vital tissue might be better than filling with foreign materials.

Results

After regenerative endodontic therapy of #8 and #7, there was radiographic evidence of periapical osseous healing and regression of clinical signs and symptoms. The pulp cavity of #8 decreased in size, and the apex closed. The pulp cavity of #7 appeared to be obliterated by mineralized tissue. These indicated ingrowth of new vital tissue into the chemomechanically debrided canals.

Conclusions

Regenerative endodontic therapy of mature teeth with apical periodontitis and apical abscess can result in the regression of clinical signs and/or symptoms and healing of apical periodontitis but no apparent thickening of the canal walls or continued root development. Filling of the disinfected canals with the host's vital tissue may be better than with foreign materials because vital tissue has innate and adaptive immune defense mechanisms.     

Enhancement of Healing Kinetics of Periapical Lesions in Dogs by the Apexum Procedure

In nonsurgical endodontic procedures, the healing of apical periodontitis is achieved by treatment provided within the root canal system. The new Apexum procedure is based on advancing the debridement one step further by minimally invasive removal of the inflamed periapical tissues through root canal access, thereby enhancing the healing kinetics of periapical lesions. The Apexum procedure uses 2 sequential rotary devices designed to extend beyond the apex and to mince periapical tissues on rotation in a low-speed handpiece, followed by washing out the minced tissue. This initial animal study was conducted to evaluate the efficacy and potential adverse effects of this procedure. Periapical lesions were induced in the lower premolars in dogs by placement of autologous dental plaque and subsequent radiographic verification. Fifty roots with periapical lesions were then subjected to cleaning, shaping and disinfection of their root canals, using a conventional root canal treatment protocol. Teeth in group 1 were subjected to the new Apexum procedure just before obturation, whereas roots in group 2 were subjected to no additional intervention before obturation. Clinical and radiographic follow-ups were carried out for 6 months. Radiographic healing of the periapical lesions in dogs at 3 and 6 months showed significantly enhanced kinetics in the Apexum-treated group compared with the conventional treatment group, at both time points (p <0.01). No noticeable adverse events occurred in either of the groups. This new procedure might significantly enhance healing kinetics of apical periodontitis compared with conventional nonsurgical endodontic treatment.     

A new bacterial species associated with failed endodontic treatment: identification and description of Actinomyces radicidentis

OBJECTIVE: This report describes 2 endodontic patients who had persistent signs and symptoms after conventional root canal treatment. The aim of this study was to determine what microorganisms were present in the root canals of the teeth with failed endodontic therapy. STUDY DESIGN: After removal of the root fillings, the canals were sampled by advanced microbiological techniques and the isolates were characterized by various tests. RESULTS: Bacteria, which grew in pure cultures, were isolated in each case. The bacteria were similar to each other and were classified as Actinomyces on the basis of phylogenic and phenotypic evidence. The bacteria were different from others within the genus, thus warranting designation as a new species, Actinomyces radicidentis. CONCLUSIONS: The 2 cases of endodontic failure were infected with A radicidentis, a new Actinomyces species. This bacterium joins a restricted group of other microorganisms that have been associated with failure of root canal treatment.     

Cholesterol As An Aetiological Agent In Endodontic Failures—A Review

Presence of cholesterol clefts in apical periodontitis lesions is a common histopathological observation. However, a potential aetiological association of cholesterol crystals to non-resolving apical periodontitis lesions after endodontic treatment has been suggested only recently. This article is an attempt to explain the biological basis for the inability of body cells to eliminate the local accumulation of cholesterol crystals, and to consolidate available clinical and experimental data in support of the view that massive accumulation of cholesterol crystals in inflamed periapical tissues can interfere with the periapical healing after conventional root canal treatment. As the irritating cholesterol crystals and certain other aetiological agents of failed endodontic treatment exist outside the root canal system, it is concluded that re-treatment alone, of such cases, is unlikely to resolve the factors that sustain the lesion. Apical surgery is indicated for successful management of such cases.     

Discuss that the coronal seal is more important than the apical seal for endodontic success

One of the main principles for successful root canal treatment is the prevention of microorganisms and toxins from the oral flora penetrating through the root canal system into the periapical tissues (1). This is achieved by obturating the root canal system completely, including the coronal and apical ends. Inadequate obturation of the root canal system has been found to be the most frequent cause of failure after endodontic treatment (2). A number of studies have indicated that leakage, whether from a coronal or apical direction, adversely affects the success of root canal treatment (3-7). The significance of the coronal seal has been increasingly recognized in the dental literature (4, 5, 8, 9) and in more recent times, it has been suggested that apical leakage may not be the most important factor leading to the failure of endodontic treatment--but that coronal leakage is far more likely to be the major determinant of clinical success or failure (10). This paper will discuss aspects of: endodontic success and failure; the use of leakage studies to assess the quality of the seal; the significance of both apical and coronal leakage; followed by a review of the literature.     

改良双敞法结合数字牙片在弯曲根管治疗中的临床评价

目的 评估改良双敞法结合数字牙片对弯曲根管治疗的效果.方法 用改良双敞法对53人53颗患牙共94个弯曲根管进行治疗,在治疗前、中、后应用数字化牙片了解根管数目形态、确定根管工作长度、判断治疗效果.结果 对53人的53颗患牙根管充填后拍摄数字牙片及观察术后反应,47例患牙根管充填后X线片显示根管成形及充填满意,其余6例不同程度地存在X线影像欠佳,满意率88.68%;53例病人有3例根管预备后有轻度术后反应( ),1例根管充填后出现中度术后反应( ),所有病例均无严重术后反应,术后急性反应率为1.89%.结论 改良双敞法结合数字化牙片在弯曲根管根管治疗中有很重要的作用,可有效改善弯曲根管治疗的效果.     

Garrè's osteomyelitis managed by root canal treatment of a mandibular second molar: incorporation of computed tomography with 3D reconstruction in the diagnosis and monitoring of the disease

AIM: To report the healing of Garrè's osteomyelitis involving a mandibular second molar following root canal treatment. SUMMARY: To describe the endodontic management of Garrè's osteomyelitis involving a mandibular second molar. In this case, computed tomography (CT) was used to evaluate the status of the periapical lesion. Five years after root canal treatment, the tooth and supporting tissues appeared healthy both clinically and radiographically and were functioning well. KEY LEARNING POINTS: Garrè's osteomyelitis of an adult can be managed by root canal treatment. Computed tomography could be used for diagnosis and treatment planning in endodontics.