自噬在延期牙再植术后炎症性牙根吸收中的作用研究

目的:观察大鼠延期牙再植术后自噬水平变化,探讨自噬在延期牙再植术后炎症性牙根吸收中的作用.方法:选取24只4周龄SD大鼠,拔除双侧上颌第一磨牙,干燥30 min后植回牙槽窝,术后1、3、7、28 d取材,染色观察炎症浸润情况、牙根表面吸收情况、肿瘤坏死因子α(TNF?α)、白细胞介素1β(IL?1β)等炎症因子表达及L...     

Effect of dexamethasone on root resorption after delayed replantation of rat tooth

The purpose of this study was to evaluate the effect of dexamethasone after delayed tooth replantation with specific regard to root resorption and ankylosis. In addition, the study was planned to elucidate further the usefulness of the model. Fifty-two maxillary first molar teeth were extracted from 26 Sprague-Dawley white female rats fed 0.4% beta-aminoproprionitrile for 3 days to facilitate the extraction. After extraction, the mesiobuccal root canals were endodontically treated under a microscope to prevent subsequent inflammatory resorption of pulpal origin and were assigned to three groups. Teeth in group 1, the dexamethasone group (n = 22), were demineralized in citric acid (1 min), washed, soaked in 1000 nM dexamethasone solution (3 min), air-dried, and replanted in the original sockets. Total extraoral treatment time for each tooth was controlled to 30 min. Teeth in group 2, the dried-only group (n = 22), were air-dried for 30 min after obturation without any surface treatment and replanted. Teeth in group 3, the immediate group (n = 8), were extracted, not root-filled and replanted immediately into their sockets. All experimental animals were killed at 3 weeks after replantation and evaluated histologically. Forty-three of the 52 teeth were available for histological interpretation. They consisted of six immediate, 18 dried-only, and 19 dexamethasone-treated teeth. The degree of progressive root resorption was significantly less in the dexamethasone-treated group than in the dried-only group (p < 0.05). The dexamethasone-treated group exhibited significantly more bone ankylosis than the dried-only group (p < 0.05). These results indicate that the topical use of dexamethasone may be of value in reducing the degree or rate of progressive root resorption secondary to traumatic avulsion and that the rat is a reasonable model for tooth replantation.     

Effects of N-acetylcysteine on root resorption after tooth replantation

In the case of complete luxation with dental trauma, delayed replantation leads to a higher probability of root resorption. We evaluated the efficacy of N-acetylcysteine (NAC) as a root canal medication for trauma-associated root resorption. A rat dental trauma model was used. In the test group, mesial root pulpectomy was carried out after tooth extraction. NAC was applied as a root canal medication followed by replantation. We euthanized the rats after two weeks, excised the maxilla, and prepared thin sections, followed by H-E and TRAP staining. Furthermore, RAW264.7 cells were treated with RANKL and NAC. The effects of NAC on osteoclast differentiation were investigated by determining the numbers of osteoclasts and nuclei and quantifying osteoclast-related mRNA expression levels by real-time PCR. The level of root resorption and number of odontoclasts tended to be lower in the NAC groups than in the control group. In terms of osteoclast differentiation, the total number of osteoclasts was lower in both the 5 and 10 mmol/L NAC groups than in the control group. Real-time PCR revealed that the expression levels of RANK, NFATc1, DC-STAMP, CD47, and cathepsin K were lower in the 10 mmol/L NAC group. NAC tended to inhibit root resorption and reduce the number of odontoclasts. NAC also inhibited the expression of osteoclast-related genes. Overall, NAC reduced the number of odontoclasts, inhibited bone resorption, and influenced the inhibition of osteoclast differentiation, fusion, and functions. Therefore, we suggest that NAC may be beneficial in the treatment of root resorption.     

人牙周膜成纤维细胞来源外泌体对大鼠延期牙再植术后牙根吸收的调控作用

目的: 探讨健康的人牙周膜成纤维细胞（hPDLFs）来源外泌体对大鼠延期牙再植术后牙根吸收的作用及其可能机制。方法: 分离提取hPDLFs来源的外泌体并鉴定。选择30只6周龄雄性SD大鼠,随机分为对照组和外泌体组,建立上颌第一磨牙延期牙再植术模型,牙脱位30 min后植回牙槽窝。对照组牙周膜局部注射40 μL汉克斯平衡盐溶液（HBSS）,实验组牙周膜局部注射40 μL含外泌体的HBSS。术后1、2、4周收样,苏木精-伊红（H-E）染色观察牙根表面吸收陷窝,抗酒石酸酸性磷酸酶（TRAP）染色观察破骨细胞数量,免疫组织化学染色观察牙周膜内骨保护素（OPG）的表达。采用SPSS 17.0软件包对数据进行统计学处理。结果: 鉴定表明提取的细胞外囊泡为外泌体。与对照组相比,hPDLFs来源的外泌体减少了延期牙再植术后牙根吸收陷窝的数量,降低TRAP阳性破骨细胞的表达（P<0.05）,促进牙周膜内OPG的表达（P<0.05）。结论: 延期牙再植术后,hPDLFs来源的外泌体减少了破骨细胞的数量,促进牙周膜内OPG表达,减少了再植术后的牙根吸收。     

完全脱位牙即刻与延迟再植根吸收的动态观察

目的：动态观察实验大鼠再植牙牙根吸收及愈合过程,辅助临床治疗及预防再植牙牙根吸收。方法：30只6周龄SPF级Wistar雄性大鼠,分为6组,每组5只,其中一组为空白对照组。实验组大鼠双侧上颌第一磨牙脱位后再植,每只大鼠随机选取一侧脱位牙齿即刻再植,对侧同名牙则于体外干燥保存30min后再植回牙槽窝。分别于术后1、3、7、14、21d处死,分离上颌骨,拍摄x线片,应用IPP软件测量上颌第一磨牙近中根根周透影面积。标本脱钙后制作切片、HE染色,进行组织学观察。结果：再植牙根尖周透影面积随时间延长而增大,干燥组表现尤其明显;组织学上表现为初期炎症反应较明显,随着炎症发展,牙根表面吸收陷窝逐渐增多、增大,后期即刻组牙髓及牙周膜修复反应明显,干燥组牙槽骨修复反应强烈,牙根、牙周膜逐渐被类骨质样组织替代。结论：再植牙初期以炎症反应为主,后期主要表现为修复反应,即刻与延迟再植导致牙周膜细胞活性不同决定了再植牙根吸收的进展。     

Effect of root surface treatment with denusomab after delayed tooth replantation

Clinical Oral Investigations - To evaluate denosumab, a human monoclonal antibody that mimics the effects of osteoprotegerin in bone metabolism, as a topical treatment of root surface to be used...     

Treatment of aggressive external root resorption with calcium hydroxide medicaments: a case report

Abstract –  Intrusive luxation is an injury involving the axial displacement of a tooth into the alveolar socket. This paper describes apexification using calcium hydroxide medicaments of an immature permanent central incisor in which spontaneous re-eruption as well as severe inflammatory external root resorption was observed following traumatic intrusion. A 10-year-old boy was referred to the Department of Pediatric Dentistry 3 days after having fallen at school. Intraoral examination revealed intrusive luxation and an enamel-dentin crown fracture of the maxillary left central incisor (Tooth 21). The tooth was not sensitive to percussion and responded positively to electric pulp test. Radiographic examination indicated that the tooth had an open apex and had been intruded approximately 3–4 mm relative to the cemento-enamel junction of the adjacent right central incisor. The tooth was left for possible spontaneous re-eruption. The crown fracture was temporarily restored using glass ionomer cement, and the patient was scheduled for recall in 2 weeks, at which time intraoral examination revealed spontaneous re-eruption of the tooth. However, radiographic examination also showed inflammatory external root resorption. The root canal was accessed and filled with a calcium hydroxide paste; however, follow-up examination indicated continuing resorption after 1 month. Calcium hydroxide plus points (CHPP) was chosen as an alternative treatment. At the end of 6 months of CHPP treatment, examination showed no further progression of external resorption and complete apexification of the tooth. After a 24-month follow-up period, no signs of pathosis were observed.     

Periapical repair and apical closure of a pulpless tooth using calcium hydroxide

A case with a wide-open apex and a large cystlike periapical lesion in an adult is presented. The lesion formed as a result of necrosis from trauma to a maxillary central incisor 12 years ago. After nonsurgical endodontic treatment with calcium hydroxide paste and a calcium hydroxide-containing root canal sealer, apical closure and significant healing of the periapical lesion within 15 months were observed. This report suggests that even large periapical lesions (likely cystic) could respond favorably to nonsurgical treatment.     

Analysis of the healing process in delayed tooth replantation after root canal filling with calcium hydroxide,Sealapex and Endofill: a microscopic study in rats

Abstract – The major concern in the therapeutics of tooth replantation refers to the occurrence of root resorption and different approaches have been proposed to prevent or treat these complications. The purpose of this study was to evaluate tissue response to delayed replantation of anterior rat teeth treated endodontically using calcium hydroxide, Sealapex, and Endofill without the placement of gutta‐percha cones. Thirty rats had their right upper incisor extracted and maintained in dry storage for 60 min. After removal of the dental papilla, enamel organ, pulp tissue, and periodontal ligament remnants, the teeth were immersed in 2% sodium fluoride phosphate acidulated, pH 5.5, for 10 min. The root canals were dried with absorbent paper points and the teeth were assigned to three groups (n = 10) according to the filling material. Group I – calcium hydroxide and propyleneglycol paste, Group II – Sealapex, and Group III – Endofill. The sockets were irrigated with saline and the teeth were replanted. Replacement resorption, inflammatory resorption and ankylosis were observed in all groups. Although the occurrence of inflammatory resorption was less frequent in Group I, there were no statistically significant differences among the groups. It may be concluded that compared to the paste, filling the root canals with Sealapex and Endofill sealers without the placement of gutta‐percha cones did not provide better results.     

Calcium hydroxide in the treatment of external root resorption

A case is presented in which calcium hydroxide was used in endodontic treatment of external root resorption in a tooth with a necrotic pulp, during active orthodontic movement. A calcified deposit formed, filling a defect, and the tooth was subsequently obturated with gutta-percha. Thus, both types of therapy--endodontic and orthodontic--were performed simultaneously.     

Effects of root canal irrigations on intracanal medication with calcium hydroxide effects in root external resorption models

Objective

The objective of the present in vitro study was to evaluate the influence of endodontic irrigation systems on the removal of smear layer and ion diffusion of calcium hydroxide through dentinal tubules in root external resorption models.

牙撕脱性损伤延迟再植的根面处理

牙撕脱性损伤是指在外力的突然作用下,牙齿完全脱出牙槽骨,牙周膜和牙髓同时损伤,牙槽窝变得空虚或伴有牙槽突的骨折。对牙撕脱性损伤的理想治疗方案是将撕脱牙即刻再植入牙槽窝,以保持附着在牙根表面牙周组织的活性。根面处理是指用药物浸泡或覆盖牙根表面,     

Treatment of external inflammatory root resorption after autogenous tooth transplantation: case report

This paper describes a case of autogenous tooth transplantation. An external inflammatory root resorption developed in a 30-year-old female patient and was successfully treated with the placement of calcium hydroxide-based intracanal dressings. Autotransplantation of tooth 32 into the extraction socket of tooth 30 was carried out with no intraoperative complications and uneventful postoperative course. However, the patient did not appear on the 14th postoperative day to initiate endodontic therapy of the transplanted tooth. She did not return for 3 months, at which time the clinical and periapical radiographic examinations revealed the presence of external inflammatory root resorption. Endodontic treatment was initiated immediately. Root canals were prepared and filled with a calcium hydroxide-based intracanal dressing (Calen paste), changed every 21 days during a 6-month period, and were thereafter obturated with Sealapex calcium hydroxide-based sealer and gutta-percha points. After 2 years of follow-up, the transplanted tooth was symptom free with no exacerbated sensibility to percussion, normal mobility, occlusion, and masticatory function. Probing revealed no periodontal pockets or other pathological signs. Radiographic examination showed the periradicular area with normal appearance, completely healed resorption areas, and presence of an intact lamina dura.     

Treatment of root surface in delayed tooth replantation: a review of literature

Abstract –  The time elapsed between a trauma and tooth replantation usually ranges from 1 to 4 h. The chances of root surface damage are higher when tooth replantation is not performed immediately or if the avulsed tooth is not stored in an adequate medium. This invariably leads to necrosis of pulp tissue, periodontal ligament cells and cementum, thus increasing the possibility of root resorption, which is the main cause of loss of replanted teeth. This paper presents a comprehensive review of literature on root surface treatments performed in cases of delayed tooth replantation with necrotic cemental periodontal ligament. Journal articles retrieved from PubMed/MedLine, Bireme and Scielo databases were reviewed. It was observed that, when there are no periodontal ligament remnants and contamination is under control, replacement resorption and ankylosis are the best results and that, although these events will end up leading to tooth loss, this will happen slowly with no loss of the alveolar ridge height, which is important for future prosthesis planning.     

Short-term vs long-term calcium hydroxide therapy after immediate tooth replantation: a histomorphometric study in monkey's teeth

Abstract – Endodontic treatment is an important step of tooth replantation protocols, but the ideal moment for definitive obturation of replanted teeth has not yet been established. In this study, a histomorphometric analysis was undertaken to evaluate the repair process on immediate replantation of monkey’s teeth after calcium hydroxide (CH) therapy for 1 and 6 months followed by root canal filling with a CH‐based sealer (Sealapex^®). The maxillary and mandibular lateral incisors of five female Cebus apella monkeys were extracted, kept in sterile saline for 15 min, replanted and splinted with stainless steel orthodontic wire and composite resin for 10 days. In Group I (control), definitive root canal filling was performed before tooth extraction. In Groups II and III, CH therapy started after removal of splint, and definitive root canal filling was performed 1 and 6 months later, respectively. The animals were euthanized 9 months after replantation, and specimens were processed for histomorphometric analysis. In all groups, epithelial attachment occurred at the cementoenamel junction or very close to this region; the areas of resorption on root surface had small extension and depth and were repaired by newly formed cementum; and the periodontal ligament was organized. Statistical analysis of the scores obtained for the histomorphometric parameters did not show any statistically significant difference (P = 0.1221) among the groups. The results suggests that when endodontic treatment is initiated 10 days after immediate replantation and an antibiotic regimen is associated, definitive root canal filling can be performed after a short‐term CH therapy.