外伤牙活力判定的方法及意义

牙外伤是口腔急诊常见的病症之一，及时准确的牙髓活力判断是正确治疗以利维持美学与功能的重要前提条件。文章通过对牙髓活力的生物学基础、牙髓活力测验方法及评价、外伤牙髓受损类型和牙髓活力特点分析，在国际牙外伤临床治疗指南的方向指导下，结合案例和经验，概括外伤牙活力与实施临床治疗方案的关系，为提高牙外伤的临床诊治思维、科学精准和个性化治疗设计提供支持，具有重要的应用价值。     

Synergism through combination of chemotherapy and oxidative stress-induced autophagy in A549 lung cancer cells using redox-responsive nanohybrids: A new strategy for cancer therapy

A combination of various therapeutic approaches has emerged as a promising strategy for cancer treatment. A safe and competent nano-delivery system is thus in urgent demand to facilitate the simultaneous transport of various therapeutic agents to cancer cells and a tumor region to achieve synergistic effect. Gold nanoparticles (GNPs) and mesoporous silica nanoparticle (MSNs) were fabricated herein as potential candidates for drug delivery. Serving as gatekeepers, GNPs (5 nm in diameter) were attached onto the amino-functionalized MSNs (denoted as NMSNs) via a relatively weak gold–nitrogen bonding. The resulting nanohybrids (denoted as GCMSNs) were uptaken by cells, and the detachment of GNPs and subsequent intracellular drug release from NMSNs were achieved by competitive binding of intracellular glutathione to GNPs. In addition to the function of gatekeeping, GNPs also play another role as the oxidative stress elicitor. Our in vitro studies revealed that GCMSNs induced higher oxidative stress in lung cancer cells (A549) than in normal cells (3T3-L1). This growth inhibitory effect found in the cancer cells was likely induced by mitochondria dysfunction originated from the GCMSN-induced, oxidative stress-triggered mitochondria-mediated autophagy. The redox-responsive nanohybrids were further loaded with camptothecin and the intensified synergistic therapeutic effects were observed associated with combined chemotherapy and oxidative stress strategy. The results clearly demonstrate that such unique nanohybrids hold great promise for selective and effective cancer treatments.     

Caffeic Acid–coated Nanolayer on Mineral Trioxide Aggregate Potentiates the Host Immune Responses,Angiogenesis, and Odontogenesis

IntroductionThe aim of this study was to investigate whether mineral trioxide aggregate (MTA) can be modified with caffeic acid (CA) to form caffeic acid/mineral trioxide aggregate (CAMTA) cement and to evaluate its physicochemical and biological properties as well as its capability in immune suppression and angiogenesis.MethodsMTA was immersed in trishydroxymethyl aminomethane buffer with CA to allow coating onto MTA powders. X-ray diffractometry and tensile stress-strain tests were conducted to assess for physical characteristics of CAMTA and to evaluate for successful modification of MTA. Then, the CAMTA cement was immersed in simulated body fluid to evaluate its hydroxyapatite formation capabilities and Si release profiles. In addition, RAW 264.7 cells and human dental pulp stem cells were used to evaluate CAMTA’s immunosuppressive capabilities and cell responses, respectively. hDPSCs were also used to assess CAMTA’s angiogenic capabilities.ResultsThe X-ray diffractometry results showed that CA can be successfully coated onto MTA without disrupting or losing MTA’s original structural properties, thus allowing us to retain the initial advantages of MTA. CAMTA was shown to have higher mechanical properties compared with MTA and had rougher pitted surfaces, which were hypothesized to lead to enhanced adhesion, proliferation, and secretion of angiogenic- and odontogenic-related proteins. In addition, it was found that CAMTA was able to enhance hydroxyapatite formation and immunosuppressive capabilities compared with MTA.ConclusionsCAMTA cements were found to have improved physicochemical and biological characteristics compared with their counterpart. In addition, CAMTA cements had enhanced odontogenic, angiogenic, and immunosuppressive properties compared with MTA. All of the results of this study proved that CAMTA cements could be a biomaterial for future clinical applications and tissue engineering use.     

Endodontic treatment of a hypertaurodontic mandibular left second molar in a patient with many taurodonts combined with multiple pulp stones

Taurodontism is a rare embryologic anomaly of teeth, defined by an apical displacement of the furcation of roots and enlarged pulp chambers. Taurodontism has been classified as hypo‐, meso‐ or hypertaurodontism according to the severity of the anomaly. The aim of this case report was to illustrate a clinical case with multiple bilateral taurodonts and to describe the endodontic management of the hypertaurodontic mandibular left second molar with a C‐shaped canal and extensive dental pulp calcifications. A healthy 20‐year‐old male patient was referred for the endodontic treatment of his lower left second molar. Cone beam computed tomography revealed a C‐shaped root canal configuration and several dental pulp calcifications in this tooth. The endodontic treatment was performed in two appointments under an operating dental microscope. A panoramic radiograph, made during the 18 months follow‐up appointment, revealed nine other taurodontic molars, most of them associated with dental pulp calcifications.     

转化生长因子β1对人牙髓细胞微丝骨架的重组作用

目的:了解转化生长因子β1(TGF-β1)对人牙髓细胞微丝和微管骨架的作用。方法:I型胶原酶消化组织块法体外培养人牙髓细胞,以20ng/ml的TGF-β1处理细胞,分别在第30min、1、6和24h收集细胞爬片,BODYPY-Phalloidin对微丝作直接荧光染色、Rhodamine RedTM对微管蛋白α(tubulin-α)作间接免疫荧光染色,采用激光扫描共聚焦显微镜观察TGF-β1作用于牙髓细胞后不同时间点微丝和微管的变化情况。结果:TGF-β1作用于人牙髓细胞后,微丝出现解聚重组现象,在30min时间点,肌动蛋白(actin)在细胞膜下聚合成纤维形肌动蛋白F-actin,同时胞质内的F-actin解聚,6h解聚最明显,24h后可见胞质内微丝重组。观察的各时间点,微管结构未见明显解聚重组现象。结论:TGF-β1能够使牙髓细胞微丝骨架重组。     

Rate and predictability of pulp revascularization in therapeutically reimplanted permanent incisors

Abstract The aim of the present investigation was to study the frequency of pulp revascularization in therapeutically reimplanted incisors as well; is its relationship with the following factors: width of apical foramen, duration of extra-alveolar lime, storage conditions and postoperative administration of antibiotics. Out of 72 immature teeth (width of apical foramen 1.1–5.0 mm) the pulp was revascularized in 13 (18%), while in 88 mature teeth (width of apical foramen 1.0 mm or less) no revascularization occurred. Among parameters tested statistically in immature teeth, a significantly increased frequency of revascularization (p < 0.05) was only found in teeth reimplanted within 45 minutes after avulsion, when compared with teeth reimplanted after a longer extra-alveolar time, and in mandibular incisors when compared with maxillary incisors (p < 0.01). All teeth in which revascularization did not occur exhibited a periapical radiolucency and/or external inflammatory root resorption.     

Effects of cooling and heating of the tooth on pulpal blood flow in man

Abstract Laser Doppler flowmetry (LDF) was used to study the changes in pulpal blood flow (PBF) evoked by application of cold or heat to the palatinal surfaces of teeth 11 or 21 in nine young subjects. Switching from a thermode temperature of 33° to 5° G on average induced a slow decrease of PBF to about 80% of control, and also warming to 39°C evoked a small reduction in most subjects. Inter individual differences were large, however, and both cooling and warming sometimes triggered a rise in PBF. In contrast, skin blood flow, as recorded with LDF in the forearm, invariably rose during warming and fell during local cooling. The results suggested a more complex interaction between local and nervously mediated effects of moderate changes in temperature in the tooth pulp than skin, and that the previous held view of cold and heat decreasing and increasing PBF, respectively, is wrong.     

纤维连接蛋白对生物矿化影响的体外实验研究

目的:探讨纤维连接蛋白(Fn)对生物矿化过程的影响,为其应用于临床作盖髓剂提供理论依据.方法:应用体外凝胶矿化系统结合微观形态学观察,研究有无羟基磷灰石(HAP)晶核时Fn对钙磷沉积的影响.结果:凝胶体系中随Fn浓度升高,吸光度值也升高(P<0.01),表明磷酸钙沉淀量的增多;加入HAP并不降低Fn的促沉积活性.结论:Fn可能通过促进钙磷沉积及其与HAP的相互作用参与矿化过程,此特性可能有利于Fn作为盖髓剂成份诱导牙本质桥形成.     

小鼠牙髓干细胞培养及诱导分化

目的 :分离、培养小鼠牙髓干细胞并诱导分化 .方法 :采用酶消化培养法获得小鼠的单个牙髓细胞悬液 ,细胞密度调整为 1× 10 4/孔细胞 ,用 2 0 0mL·L -1胎牛血清的α MEM培养液培养 14d ,挑出细胞克隆消化传代 ,TGF β、BMP2 、bFGF细胞因子诱导 ,PCR检测DSPP的mRNA的表达 .结果 :小鼠牙髓细胞呈集落状生长 ,克隆形成率为 1.6 -2 .5个 / 10 4细胞 ,所形成的集落细胞结合紧密 ,细胞体积小、胞核大 ,经细胞因子刺激后的细胞表达DSPP的mRNA .结论 :培养的小鼠牙髓集落状生长的细胞具有干细胞增殖快等特性 ,细胞因子可诱导小鼠牙髓干细胞定向分化