Quantitative scintigraphic analysis of pulp revascularization in autotransplanted teeth in dogs

Objective: The purpose of this study was to evaluate the pulpal changes associated with autogenous single-rooted immature tooth transplantation in dogs, using either one, or two-stage surgical techniques. Methods: Teeth from 3 beagle dogs, 5 months old, were extracted and transplanted to mechanically prepared recipient sockets. Group (A), where the teeth were transplanted using a one-stage method to recipient beds prepared immediately before transplantation. Group (B), where the teeth were transplanted using a two-stage method in which the recipient beds were prepared and left to heal for 7 days before transplantation. Clinical examinations were done every week during 9 weeks. After 9 weeks, the animals were injected with ^99mTechnetium hydroxylmethylene diphosphonate (^99mTc-HMDP) and 3 h after injection, a whole body scintigraphic acquisition was performed. After scintigraphic acquisition the animals were euthanized and the teeth extracted and its radioactivity counted in a well counter calibrated to ^99mTc. With the data obtained, the percentage of activity injected was calculated for each tooth. The data for each group of teeth were evaluated and analyzed using the Mann-Whitney test (p = 0.05). Results: All the transplanted teeth in both groups survived. No statistically significant difference was found in the absorption of the ^99mTc-HMDP, between the treatment groups (p = 0.464) and between them and the control group (Group A vs. control p = 0.713 and Group B vs. control p = 0.157). Conclusions: This study demonstrated that there was no difference between the two surgical techniques in terms of the pulp revascularization in transplanted teeth.     

Histologic characterization of regenerated tissues after pulp revascularization of immature dog teeth with apical periodontitis using tri-antibiotic paste and platelet-rich plasma

IntroductionThis study evaluates histologically the efficacy of 4 revascularization protocols in necrotic-infected immature dog teeth with apical periodontitis (AP).MethodsForty double-rooted immature premolar teeth from 4 female Beagle dogs aged 5 months were used. Four teeth were left untouched as negative controls; the other 36 teeth were infected to develop pulp necrosis and AP. Four teeth were left untreated and assigned to the positive control group. The last 28 teeth were randomly assigned into four experimental groups of 8 teeth, each one treated with a different treatment protocol: A1, sodium hypochlorite (SH) + blood clot (BC); A2, SH + platelet-rich plasma (PRP); B1, SH + modified tri-antibiotic paste (mTAP) + BC; B2, SH + mTAP + PRP. The animals were sacrificed, histologic sections were prepared and three parameters were assessed: (1) presence or absence of new hard tissue on the internal root dentinal walls, (2) presence or absence of continued apical closure, and (3) presence or absence of vital tissue within the canal space.ResultsSignificant differences (p < 0.05) between the four experimental groups were evident in the percentage of teeth showing histological apical closure (34.5%) and vital tissue within the canal space (68.8%). Group B2 showed the maximal improvement in the three variables assessed (p < 0.05). Group A1 showed the minimum percentages in the three parameters assessed (p < 0.05).ConclusionsThese results suggest that an intracanal dressing of mTAP, and the use of PRP as scaffold, improves the success rate of the revascularization procedure.     

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。     

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。     

年轻恒牙牙髓血运重建术临床效果初步观察

目的:评价因外伤、发育畸形所致根尖周炎或牙髓坏死的年轻恒牙牙髓血运重建术后的疗效及影响因素.方法:回顾分析66例因根尖周炎或牙髓坏死行血运重建治疗的年轻恒牙,采用Mimics软件重建患牙治疗前后的根尖周病损三维模型并测量体积,采用Dolphin软件测量患牙治疗前后的牙根长度、根管壁厚度及根尖孔大小,评估治疗后患牙根尖周...     

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.     

Response of autotransplanted teeth to electric pulp testing

OBJECTIVE: The purpose of this retrospective study was to assess the results of third molar autotransplantation by using electric pulp testing (EPT) and to determine the correlation of EPT response and bone formation. STUDY DESIGN: Fourteen patients with 22 transplanted teeth were studied. The patients had received autotransplantation of third molars and regularly came for follow-up on the third, sixth, ninth, and twelfth months. Postoperative clinical assessment included pain, inflammation of surrounding soft tissues, tooth mobility, and the EPT response. Periapical radiographs were subsequently evaluated during follow-up. The correlation between pulpal response to EPT and bone healing was analyzed. RESULTS: Most of the teeth had normal mobility within 3 months, which corresponded to bone formation. Bone healing at the recipient sites completely occurred within 6 months, and more than 50% had lamina dura. The teeth with EPT response increased to 95% within 12 months. There was no significant association between the EPT response and bone formation. CONCLUSIONS: The EPT response subsequently increased with time, and it seemed to be unchanged after 1 year.     

牙髓血运重建治疗年轻恒牙根尖周病变的临床观察

目的 观察年轻恒牙进行牙髓血运重建术后牙根发育及根尖周病变愈合情况.方法 选取慢性根尖周炎或慢性根尖周炎急性发作的单根管年轻恒牙16例,要求牙根发育Nolla分期7～9期.行牙髓血运重建术治疗,随访观察2年,定期进行临床检查并拍摄X线片观察牙根发育及根尖周病变的愈合情况.结果 16例单根管年轻恒牙牙髓血运重建术后12例牙根继续发育.其中13例在定期复查时牙髓电活力测试结果表现为阳性;16例术后根尖周病变均完全愈合,愈合时间因病变大小而不同,平均愈合时间为4.1个月.疗效评价为成功12例,好转4例,失败0例.结论 牙髓血运重建术治疗年轻恒牙根尖周病变,取得良好的治疗效果.     

Pulp revascularization of replanted immature dog teeth after different treatment methods

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).     

Tissue changes in immature dog teeth autotransplanted to surgically prepared sockets.

Tissue reactions in teeth autotransplanted to surgically prepared sockets were investigated by means of microangiographic, enzyme histochemical, and histologic methods. The experimental material consisted of 28 immature teeth in six mongrel dogs. In each tooth, approximately three fourths of the root was formed at the time of transplantation. Ten days after transplantation, a vascularized, well-stained connective tissue was observed in the apical area of the pulp. An ingrowing tissue had reached the pulp horn in all teeth 90 days after surgery. Odontoblasts were not found in any of the transplanted teeth. External root resorption was seen in all teeth but repair usually occurred approximately parallel to the ingrowth of new tissue into the pulp cavity. In a few teeth, however, advanced inflammatory root resorption was observed in cracks in the cervical area. When compared with the results of a previous study, the ingrowth of tissue occurred at a considerably slower rate than in teeth autotransplanted to natural sockets.     

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).     

Influence of orthodontic derotation and extrusion on pulpal and periodontal condition of autotransplanted immature third molars.

The aim of this study was to determine the influence of orthodontic treatment on the pulpal and periodontal condition of 91 transplanted immature third molars. In patients with atrophy of the alveolar process or unfavorable root morphology, transplants had to be placed in extreme rotated or infraoccluded positions. After 3 to 6 months, these transplants were derotated (45 degrees to 90 degrees) to a correct position in the dental arch (derotation group; n = 28) or extruded to the occlusal plane (extrusion group; n = 21). Finally, approximal spaces were closed in both groups. A sample of 42 transplanted third molars with no orthodontic treatment need served as the control group. All transplants were followed clinically and radiologically for a mean period of 4.0 years. With respect to pulpal and periodontal conditions, no significant differences were observed between the control and the extrusion group. In contrast, compared with the control group, transplants in the derotation group had a significantly poorer pulpal and periodontal condition. In the derotated transplants, a significant correlation was detected between pulp necrosis and orthodontic treatment of multi-rooted transplants. This study indicates that orthodontic extrusion and minor lateral movements of autotransplanted immature third molars, as well as rotation of single-rooted third-molar transplants, represent no additional risk to transplant survival. In contrast, rotation of multi-rooted transplants seems to initiate later severance of the vascular and nerval supply to the pulp.     

Vascular pathways within pulpal tissue of human primary teeth.

The vascular distribution within pulps of human primary teeth has not been as well studied as those within human permanent teeth. Such information is useful to those who diagnose and treat dental conditions in children. The purpose of this study was to determine the architecture of the vascular structures, in contrast to the histological appearances, of noncarious human primary teeth during root completion, root resorption and dental caries attack. Following extraction, primary teeth were perfused with an opaque injection mass and photographed to trace the courses of the arterioles, venules and capillaries within the crowns and roots. The architectural morphology of similar vascular structures in permanent pulps are included to provide a comparative reference. Arterioles entered the apical foramina and traveled throughout the root canal(s) to the pulpal chamber, giving off branches which passed toward the dentinal walls. Within the pulpal chamber, the arterioles passed toward the occlusal and proximal surfaces and arborized profusely to form a subodontoblastic plexus of capillaries. The capillaries lead to larger diameter venules, which exited the pulp through apical foramina. Many unusual vascular pathways existed within the root structure. No communication existed between the pulp chamber and periodontal membrane through the furcation dentin and cementum. Many lateral canals were seen along the root structures.     

The effectiveness of pulp revascularization in root formation of necrotic immature permanent teeth: A systematic review

Objective. The objective of the present study was to carry out a systematic review to analyse the effectiveness of pulp revascularization in the root formation of necrotic immature permanent teeth, as well as the level of scientific evidence regarding this theme. Materials and methods. The methodology was based on searching electronic databases such as Web of Science, Pubmed, BVS (Medline, Scielo, Lilacs and BBO), Scopus and Cochrane, including manual searches for the references listed in the studies found. The terms used for the literature search were pulp revascularization and endodontics. Results. Initially, 277 articles were identified from the electronic databases; 17 studies remained after analysis and exclusion of duplicates; exclusion criteria also eliminated six articles; 11 remained for evaluation. Conclusions. Although the results found in the present systematic review are relevant, the scientific evidence should be interpreted with caution as the articles report different methods and evaluation parameters. Despite the capacity of the pulp revascularization technique to stimulate the development of the apical closure and thickening of radicular dentin, several aspects still remain unknown, like the key factors of this repair, the type of tissue formed and the long-term prognosis.     

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。