Pulp revascularization for immature replanted teeth: a case report

Immature avulsed teeth are not usually treated with pulp revascularization because of the possibility of complications. However, this therapy has shown success in the treatment of immature teeth with periapical lesions. This report describes the case of an immature replanted tooth that was successfully treated by pulp revascularization. An 8‐year‐old boy suffered avulsion on his maxillary left lateral incisor. The tooth showed incomplete root development and was replanted after 30 minutes. After diagnosis, revascularization therapy was performed by irrigating the root canal and applying a calcium hydroxide paste and 2% chlorhexidine gel for 21 days. In the second session, the intracanal dressing was removed and a blood clot was stimulated up to the cervical third of the root canal. Mineral trioxide aggregate was placed as a cervical barrier at the entrance of the root canal and the crown was restored. During the follow‐up period, periapical repair, apical closure and calcification in the apical 4 mm of the root canal was observed. An avulsed immature tooth replanted after a brief extra‐alveolar period and maintained in a viable storage medium may be treated with revascularization.     

犬年轻恒牙血管再生法动物模型建立的影响因素

目的：探讨犬年轻恒牙血管再生法动物模型建立的影响因素。方法：杂种犬3只,选取牙根未发育完成的上颌恒前牙及下颌恒前磨牙共36个牙根为样本,建立根尖周炎模型后构建血管再生法动物模型。结果：3个牙根未形成血凝块,4个牙根MTA充填不佳,7个牙根出现了牙周炎,5个牙根冠折,1个牙根脱落。结论：血凝块的质量,矿化三氧化聚合体（MTA）的充填技术,牙周炎的出现,疼痛等因素对模型的建立有一定的影响。     

根管内血运重建用于年轻恒牙牙髓坏死的治疗

近年来随着生命科学、材料科学以及相关各学科的发展,人们对年轻恒牙的再生能力有了新的认识。再生性牙髓治疗作为牙髓坏死后一种新的治疗方式,因其可能带来的较传统治疗方法更为理想的预后开始成为研究的热点。其中根管内血运重建以其简便易行,成本相对较低,不涉及免疫排斥和伦理问题等优势获得了人们的关注。本文将就该治疗方式的发展历史及其在年轻恒牙牙髓坏死治疗中的应用等方面作一综述。     

Pulp revascularization of replanted immature dog teeth after different treatment methods

Abstract – The purpose of the present study was to determine the effect of topical treatment with doxycycline and/or the application of unfilled resin to the anatomical crown on the occurrence of revascularization in reimplanted dog teeth. Ninety-six teeth in 4 young mongrel dogs were used. Eighty one teeth were atraumatically extracted and divided into four groups. Group 1, 17 teeth were kept dry for 5 min and then replanted. Group 2, 21 teeth were soaked with a freshly prepared solution of doxycycline (1 mg/20 mL saline) for 5 min before replantation. Group 3, 23 teeth were soaked with the doxycycline solution for 5 min, and then replanted. The crowns were coated with 2 layers of light cured unfilled resin. Group 4, 20 teeth were kept dry for 5 min, and then replanted. The crowns were treated as with the teeth in Group 3. Three months after surgery, radiographic evaluation revealed that 27 teeth had continued root development and 32 teeth showed arrested root development with periradicular pathosis. The remaining 17 teeth, which had arrested root development but no signs of periradicular pathosis, were all histologically evaluated for final assessment. The occurrence of revascularization according to treatment group was 29.4%, 60%, 60%, 36.8% in Group 1, 2, 3, and 4, respectively. A multiple logistic regression analysis in SAS indicated there was no significant association between vitality and dog ( P =0.7564). Soaking for 5 min in doxycycline significantly increased the revascularization rate ( P =0.024) while the addition of resin to the crown did not result in an increased incidence of pulp revascularization ( P =0.823).     

血管再生治疗犬年轻恒牙根尖周炎的实验研究

目的：比较血管再生和根尖诱导成形术治疗犬年轻恒牙根尖周炎的效果。方法：选用3只5-6个月犬的30颗双根前磨牙,建立根尖周炎模型,三联抗生素糊剂消毒后,随机分为三组,即血管再生组、根尖诱导组和空白对照组。于术后4周、8周、12周分别拍摄X线片,比较根尖愈合情况。术后12周处死动物,常规制作组织切片,观察管腔内再生组织的成分以及根尖硬组织形成情况。结果：①X线观察：三组均可看到根尖闭合影像,两实验组的根尖闭合率优于对照组（P〈0．05）,实验组之间差异无统计学意义（P〉0．05）。②组织形态学观察：血管再生组和对照组有类似于牙骨质样组织（管内牙骨质）从根尖孔向内延伸,在管壁沉积,管腔内出现骨样组织（管内骨组织）,共同促使牙根伸长和管壁增厚,且血管再生组的两种组织发生率优于对照组（P〈0．05）,根尖诱导组未见此两种组织。结论：血管再生在管壁增厚和牙根伸长等方面优于根尖诱导成形术。     

年轻恒前牙感染根管内血管再生的动物实验研究

目的通过建立根尖周炎模型观察年轻恒前牙根管内血管再生的组织学状况。方法选择4个半月龄杂种犬1只,建立上颌未发育完成的恒前牙根尖周炎模型,将6颗上颌恒前牙随机分组,对照组3颗采用根尖诱导成形术,实验组3颗采用根管内血管再生术。将术后1、4、8周的X线片分别与术前X线片进行对比,观察牙根继续发育及根尖炎症的愈合情况。术后8周处死动物,利用苏木精-伊红（HE）染色观察根尖闭合情况及根管内容物的构成。结果X线观察,术后1、4周,2组牙根的根尖孔大小及根尖透射区范围未见明显改变。术后8周,实验组根尖透射区范围缩窄较明显,并出现根尖孔缩窄的趋势,但管壁厚度无明显变化;而对照组根尖透射区变化不一。组织学检查,实验组管腔内可见肉芽组织,其中包含有大量的不规则的类牙本质、类牙骨质和类骨质样钙化物,钙化物以根尖部和管腔内侧壁尤为明显。对照组管腔未见软组织,根尖部有少量的硬组织沉积。结论血管再生术可促使年轻无髓恒前牙的慢性根尖周炎症消退,根管内再生的肉芽组织中有硬组织沉积。     

Revascularization of immature permanent teeth with apical periodontitis

The aim of this minireview was to identify and review the scientific evidence regarding regenerative endodontic protocols claiming to revascularize permanent immature teeth with apical periodontitis. The literature was identified using the PubMed/MEDLINE, Scopus, Scirus, EMBASE and Cochrane databases up to February 2013. Studies were selected independently by two different researchers (kappa index: 0.88), based on established inclusion/exclusion criteria. The methodological quality of the reviewed papers was classified as high, medium or low (HQ, MQ, LQ). The search strategy identified 285 titles. Nine studies, both human and animal based, were selected after application of the criteria (LQ:5; MQ:4). In most of these studies (seven of nine), the revascularization protocol included a triple antibiotic combination as canal disinfectant for a period of 1–4 weeks after blood clot formation (LQ:5; MQ:4), although there is no clear consensus about the treatment protocol. Two studies reported tooth discoloration after the revascularization process (LQ:2), and only three (LQ:1; MQ:2) reported a success rate of 54.9% in dogs and 73.6% and 80% in humans, respectively. Revascularization of immature permanent teeth with apical periodontitis is possible and preferable to apexification. Nevertheless, there is a widespread lack of randomized clinical trials and blinded measures. In addition, the small sample sizes that are common in these studies as well as the generally low quality of the analysed publications require the results to be viewed with caution. There is a high risk of bias, with a low quality of available information, for developing clinical guidelines for regenerative endodontic protocols; rigorous randomized clinical trials are therefore needed.     

Tissue reactions after experimental luxation injuries in immature rat teeth

Abstract Immature permanent teeth often develop complications after luxation injuries. The pathology and the degenerative processes of the complications, however, are not well understood. In this study, we histologically examined the long–term reactions of immature rat teeth after standardized luxation injuries delivered in our previously developed experimental model. The upper first molars of 3-week-old male Wistar rats weighing 50-60 g were pushed horizontally toward the palate to cause a constant amount of dislocation. The follow-up changes of the luxated molars were studied up to 56 days after the trauma. Soon after the trauma, the periodontium had irregular fibers, degenerated cells, hemorrhage and edema in various places. After 12 h, a cell free area appeared in the palatal periodontium. In the alveolar bone and on the surface of the root, resorption occurred one day and 5-7 days after injury respectively. Although the damage in the periodontium and alveolar bone was gradually repaired, the root resorption, especially in the palatal cervical region, continued throughout the experimental period. In the most cases, the dental pulp did not seem to be damaged immediately after the trauma. By the 3rd day after injury, however, displacement of odontoblasts into the dentinal tubules was observed in many teeth. Moreover, formation of irregular dentin was observed in some teeth after 7 days. These changes of the pulp tended to disappear in the later stages of the experiment.     

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提要：牙髓血运重建术通过彻底有效的根管消毒,尽量保护牙髓干细胞和牙乳头间充质干细胞,并为这些干细胞的增殖和分化提供良好的环境,使其在信号分子和盖髓剂矿物三氧化物凝聚体的诱导下,分化为成牙本质细胞和成牙骨质细胞等,从而使牙根在长度和厚度上得以继续发育。在不久的将来,牙髓血运重建术有可能成为年轻恒牙牙髓病变和部分根尖周病变的首选治疗方法。本文就近年来有关牙髓血运重建的实验室和临床研究进展做一综述。     

iRoot BP Plus与MTA行年轻恒牙血运重建术的效果对比分析

目的 探讨在年轻恒牙血运重建术中,iRoot BP Plus与无机三氧化物聚合物(MTA)两种不同材料的应用效果比较.方法 选择我院接诊的年轻恒牙血运重建术患者100例(100颗患牙),根据患者使用填充材料情况,MTA组50例(50颗牙,失访2例),iRoot BP Plus组50例(50颗牙,失访1例),对比两组填充...     

Efficacy of laser Doppler flowmetry for the diagnosis of revascularization of reimplanted immature dog teeth

Abstract – This study was performed to assess if laser Doppler flowmetry (LDF) is an improved method for the detection of revascularization of replanted teeth. Teeth were extracted and reimplanted under different experimental conditions. LDF readings were taken before extraction and weekly for 3 months. In control teeth, LDF baseline readings were taken and then repeated after the apical blood vessels were cut surgically. At the end of 3 months it was determined radiographically and histologically whether revascularization had occurred, i.e. vitality had returned. Results: LDF readings correctly predicted the pulp status (vital vs. non-vital) in 83.7% of the readings. 73.9% (17 of 23) were correct for the vital teeth and 95% (19 of 20) were correct for the non-vital teeth. Fisher's exact test (2-tail) indicated that there was no significant association between the efficacy of LDF and tooth type ( P= 0.166), although P2 was the least accurate tooth tested. Wilcoxon's matched-pair signed rank test demonstrated that in the revascularized (vital) teeth, the flux value between the baseline and week 2 dropped significantly ( P= 0.0001), increased significantly from week 2 to week 4 ( P= 0.0001) and then decreased steadily until week 12. However, at week 12 the flux was still significantly higher than at week 2 ( P= 0.010). In the teeth that failed to revascularize, the flux value dropped significantly by weeks 1 and 2 ( P= 0.004 and P= 0.0001, respectively). Flux values did not increase from week 2. A Fast Fourier Transform (FFT) analysis confirmed a pulse of dominant frequency of 2 Hz in the teeth that returned to vitality and the lack thereof in those that stayed non-vital. One tooth in which the flux value evaluation indicated a non-vital tooth but the radiographic/histologic findings showed vital (false negative) possessed a pulse of dominant frequency and proved by this method to have successfully revascularized.     

A scoping review of root canal revascularization: relevant aspects for clinical success and tissue formation

The aim of this scoping study was to evaluate the survival rate and nature of tissue formed inside root canals of human immature permanent teeth with necrotic pulps (NIPT) under root canal revascularization (RCR). The search was performed in SciVerse Scopus®, PubMed/MEDLINE, Web of Science®, BIREME and in the grey literature up to November 2015. The keywords were selected using MeSH terms and DECs. Two independent reviewers scrutinized the records obtained considering specific inclusion criteria. The included studies were evaluated in accordance with a modified Arksey and O’ Malley's framework. From 375 studies that were evaluated, 75 were included. A total of 367 NIPT were submitted to RCR, from which only 21 needed further endodontic treatment. The weighted mean follow‐up time was 17.6 months. The data were derived mainly from case reports (69%) or small case series (15%). NaOCl [0.5–6%] was applied as the disinfecting solution in almost all studies. Triple antibiotic paste was as effective as Ca(OH)₂ as on intracanal medicament. De novo tissue was cementum and poorly mineralized bone positive to bone sialoprotein (BSP) but negative to dentine sialoprotein (DSP). Failures were associated mainly with reinfection of the root canal. The majority of included studies reported a significant increase in both root length and width. However, as most of these data came from case reports, they must be interpreted with care, as most were focused on treatment successes (not failures). Therefore, well‐designed randomized controlled trials comparing RCR with available apexification treatments are needed to address this gap in the literature.     

血管再生研究进展及其应用

20世纪80年代末期,随着生命科学、材料科学及其相关的物理化学学科的发展,组织工程学成为口腔医学领域的研究热点,催生了再生牙髓病学的诞生.下面就再生牙髓病学中的根管内血管再生的血管生成模式、血管再生在相关疾病中尤其是在牙髓疾病中的应用等研究进展作一综述.     

Pulp capping of immature teeth with anatomic anomalies

Abstract This case report describes the treatment of two immature teeth with anatomic anomalies which created plaque retentive areas and in one case occlusal disturbance. Periodontal and pulpal consequences were inevitable. Reshaping of the teeth was carried out which as expected led to exposure of the pulp in both instances. Pulp capping was then performed under aseptic conditions. The vitality of the teeth was maintained and continued root development was observed.     

Structural resistance in immature teeth using root reinforcements in vitro

Abstract –  The purpose of this study was to evaluate in vitro the efficacy of root reinforcements by light-cured composite resin or zirconium fiber post in simulated immature non-vital teeth. Fifty-six bovine incisors teeth were used for this study. The crown of each tooth was removed in the medium third to obtain a standard length of 30 mm. The specimens were divided into four groups ( n  = 14): G1) the root canals were instrumented and enlarged to simulate immature non-vital teeth and were reinforced with a light-cured composite resin using a translucent curing post (Luminex system); (G2) the specimens were instrumented, enlarged and they received root reinforcement with zirconium fiber post; G3 (positive control): they received similar treatment to the G1 and G2 groups, but did not receive root reinforcement; G4 (negative control): the roots were not weakened and did not receive reinforcement. Every tooth was submitted to compressive force using an Instron testing machine with an angle of 45° at a speed of 1 mm min⁻¹ until the fracture. The results showed a markedly increased resistance to fracture in the G1 and G2 ( 122.38 and 122.08 kgf, respectively). Among the results of G1 and G2 there was not any significant difference (P > 0.05) but they were significantly different from the control groups (P < 0.05). The conclusion is that the use of root reinforcements with zirconiun fiber post or composite resin can increase significantly the structural resistance of the weakened teeth, decreasing the risk of the fracture.     

Periodontal healing after intentional auto-alloplastic reimplantation of injured immature upper front teeth

BACKGROUND/AIMS: Conventional endodontic treatment results in high complication quota when performed in immature teeth. Intentional reimplantation with extraoral insertion of an endodontic implant (auto-alloplastic reimplantation) is an alternative. METHOD: In a retrospective study, the healing of 40 teeth reimplanted intentionally according to this method in patients aged 7 to 15 years was evaluated. Clinical tests (palpation, percussion sound, periotest values) and radiographical examinations were used to determine the type of periodontal healing (inflammatory resorption/periodontitis apicalis; replacement resorption/ankylosis; normal healing). RESULTS: Mean lifetime of the replanted teeth was 59.2+/-42.5 months, estimated survival time on the basis of the Kaplan-Meier analysis was 99.5 months. 17 teeth (42.5%) were classified as failures, mostly due to inflammatory resorption or periodontitis apicalis. Further investigations demonstrated that success rate and retention period of intentionally replanted teeth depend on the preoperative condition of the pulp. Teeth with preoperative infection suffered frequently from inflammatory resorption or periodontitis apicalis after being replanted (14 of 28 teeth). Estimated survival time according to Kaplan-Meier was 75.5 months. In contrast, inflammations or progressive resorptions were not observed in teeth without preoperative infection of the pulp. All these 12 teeth showed normal periodontal healing and regular tooth mobility. In the absence of any pathology in clinical or radiological findings after an average functional period of 72.3 months, the prognosis can be presumed excellent. Estimated survival time of 148.3 months according to Kaplan-Meier differs significantly from survival time of teeth infected preoperatively. CONCLUSIONS: From the results of this investigation, it may be concluded that an infection of the pulp - due to delay of treatment or attempts at endodontic therapy - should be avoided before intentional replantation of immature front teeth with pulp necrosis. Periodontal healing of the autologous root is not impaired by the insertion of posts made of Al2O3-ceramics or titanium. The inserted posts do not ankylose. Orthodontic movement of auto-alloplastically replanted teeth is possible.