Objective The physiological occlusal force generated by mastication plays a critical role in tooth replantation after complete avulsion by promoting periodontal ligament healing. Heme oxygenase-1 (HO-1), a classical cytoprotective factor, exhibits mechanoresponsive expression in periodontal ligament cells (PDLCs). This study aims to investigate whether occlusal force can reduce replacement root resorption during the healing of periodontal ligament in replanted teeth and its potential mechanisms. Methods A tooth avulsion model was established in occlusal group rats and occlusal deprivation group rats. The healing of periodontal ligament was evaluated at 7 and 28 days post-replantation using micro-computed tomography, histological analysis, and immunohistochemistry. PDLCs were isolated to construct the injured periodontal ligament cells (iPDLCs) model. Following the application of cyclic tensile force, collagen synthesis level and the expression changes of HO-1 and transforming growth factor-beta 1 (TGF-β1) were assessed. Results The physiological occlusal force reduced replacement root resorption, promoted periodontal healing and the conversion of type III collagen (COL Ⅲ) to type I collagen (COL Ⅰ), and increased HO-1 expression in the periodontal ligament of replanted rat teeth. The cyclic tensile force (4% strain, 0.5 Hz) applied for 4 hours upregulated the expression of HO-1, COL Ⅰ, and COL III in iPDLCs. Enhanced HO-1 expression increased the levels of TGF-β1, COL I, and COL III, whereas inhibition of HO-1 or blockade of TGF-β1 reduced COL I and COL III expression. Simultaneous upregulation of HO-1 and inhibition of TGF-β1 resulted in decreased COL I and COL III expression. Conclusion Physiological occlusal force may be associated with reduced replacement root resorption and elevated HO-1 expression, while also promoting collagen synthesis in the injured periodontal ligament. Low deformation with short-term cyclic tensile force induces HO-1 expression, thereby promoting COL I and COL III synthesis in iPDLCs. This process is closely associated with the TGF-β1 signaling pathway.

The development of new artificial biomaterials for bone defect repair is an ongoing area of clinical research. Metal ions such as zinc, copper, magnesium, calcium, strontium, silver, and cerium play various roles in bone tissue regeneration in the human body and possess a range of biochemical functions. Studies have demonstrated that appropriate concentrations of these metal ions can promote osteogenesis and angiogenesis, inhibit osteoclast activity, and deter bacterial infections. Researchers have incorporated metal ions into biomaterials using various methods to create artificial bone materials with enhanced osteogenic and antibacterial capabilities. In addition to the osteogenic properties of all the aforementioned metal ions, Zn, Sr, and Ce can indirectly promote osteogenesis by inhibiting osteoclast activity. Cu, Mg, and Sr significantly enhance angiogenesis, while the antibacterial properties of Zn, Cu, Ag, and Ce can reduce the likelihood of infection and inflammation caused by implanted materials. This paper reviews the mechanisms through which metal ions promote bone tissue growth and improve the antibacterial activity of biomaterials. It also summarizes common loading methods on the surface of biomaterials with different metals and highlights the potential clinical applications of these new artificial bone materials.

EDITORIAL article Front. Physiol., 15 September 2023Sec. Skeletal Physiology Volume 14 - 2023 | https://doi.org/10.3389/fphys.2023.1285197

背景:局部应用生长因子是牙周组织再生治疗的方法之一,然而由于生长因子半衰期短、易被稀释和水解等因素导致其局部应用受到限制.药物缓释系统能够控释生长因子使其更有效地发挥生物学功能.目的:综述药物缓释系统的概念、分类及其在牙周组织再生领域的应用.方法:应用计算机以"载体,药物缓释系统,牙周组织再生,纤维,膜片,条带,水凝胶,脂质体,聚合物胶束,微球"为中文关键词,以"carrier,drug delivery system,periodontal tissue regeneration,fibers,films,strips,hydrogel,liposome,polymer micelle,microsphere"为英文关键词,检索PubMed、中国知网、万方、维普数据库中的相关文献,初筛得到文献240余篇,通过筛选、归纳与总结,最终纳入71篇相关文献进行综述.结果 与结论:药物缓释系统既可以实现对生长因子的控制释放,又可以保护生长因子的生物活性,从而发挥促进受损组织修复和再生的作用.根据剂型不同可将药物缓释系统分为纤维体系、膜片或条带体系、水凝胶体系和微纳药物输送系统.随着药剂学、高分子材料学和牙周病学等发展,具有生物相容性和生物可降解性的材料逐渐应用于牙周生长因子缓释制剂的研究和生产中,为牙周病的临床治疗提供新方向,但从载体材料的安全性、制备方法的可操作性、临床应用的普适性这些方面考虑,许多用于牙周再生领域的药物缓释技术仍然有待完善.

目的 探讨文献阅读式教学法在口腔医学本科生中的教学效果.方法 以中国医科大学2016级本科生为教学对象,比较文献阅读式教学法实施前后的测试成绩,通过问卷调查了解学生对该教学法的评价.结果 文献阅读式教学法显著提高了口腔医学本科生的医学文献相关知识和科研基础理论的测试成绩;97.6％的学生认为该教学法对将来研究生阶段的学习会有很大帮助.结论 文献阅读式教学法能够切实提升本科生的基本科研素养,值得在本科生教学中推广使用.

Objective This study investigated the effects of poly lactic-co-glycolic acid (PLGA) loaded with plasmid DNA encoding fibroblast growth factor-2 (pFGF-2) on human periodontal ligament cells (hPDLCs) in vitro and evaluated the ability of the PLGA/pFGF-2 scaffold to promote periodontal ligament (PDL) regeneration in a beagle dog teeth avulsion animal model. Background Growth factor and scaffold play important roles in PDL regeneration. PLGA is a kind of biodegradable and biocompatible polymer that can be used as a carrier to deliver growth factors or genes. FGF-2 can induce potent proliferative responses, promote cell migration and regulate the production of extracellular matrix. Therefore, a gene-activated matrix composed of scaffold and genes is supposed to be a superior approach for promoting tissue regeneration. Methods In this study, PLGA and PLGA/pFGF-2 scaffolds were fabricated using electrospinning. The characterization of scaffolds was shown by scanning electron microscope (SEM) and transmission electron microscope (TEM). dsDNA HS was used to test the plasmid release of PLGA/pFGF-2 scaffold. The viability and proliferation of hPDLCs on the two kinds of scaffolds were evaluated by the CCK-8 assay, and the expression of collagen I and scleraxis were analysed by RT-qPCR. The roots of avulsed teeth were covered by the two types of scaffolds and replanted into the alveolar pockets in beagles. Haematoxylin-eosin and Masson staining were used to evaluate the effects of PLGA/pFGF-2 scaffold on promoting PDL regeneration. Results The smooth and uniform fibres can be observed in both scaffolds, and the plasmids were randomly distributed in the PLGA/pFGF-2 scaffold. dsDNA HS analysis demonstrated that the PLGA/pFGF-2 scaffold released up to 123 ng pFGF-2 over 21 days in a sustained manner without any obvious burst release. The PLGA/pFGF-2 scaffold promoted the proliferation of hPDLCs and increased the expression levels of collagen I and scleraxis compared with PLGA scaffold. Animal experiments showed that more regular PDL-like tissues and less root surface resorption occurred in the PLGA/pFGF-2 scaffold group compared with the PLGA scaffold group. Conclusions The PLGA/pFGF-2 scaffold promoted hPDLCs proliferation and facilitated periodontal ligament-related differentiation. The PLGA/pFGF-2 scaffold possesses excellent biological characteristics and could be used as a promising biomaterial for improving the treatment prognosis of replanted tooth.

OBJECTIVES:This study investigated whether novel liposome formulations loaded with transforming growth factor β1 (TGF-β1) could promote the odontogenic differentiation of human dental pulp stem cells (hDPSCs) for dentine-pulp regeneration.METHODS:0-100 ng/mL of liposomal TGF-β1 was prepared using the thin-film hydration method. Release of TGF-β1 from the liposomes was quantified by an enzyme-linked immunosorbent assay (ELISA). The hDPSCs were treated with different concentrations of liposomal TGF-β1 and cell viability was tested using an MTT assay. "Osteodentine" differentiation capacity was assessed by RT-qPCR, ELISA and Alizarin red S staining.RESULTS:The ELISA results showed that liposomal TGF-β1 achieved a controlled and prolonged release over time. The MTT results demonstrated that the liposomes (100 μg/mL) were not cytotoxic to the cells. Liposomal TGF-β1 up-regulated the expression of "osteodentine" markers, RUNX-2, DMP-1 and DSPP, in hDPSCs after 7 days of treatment and resulted in the accumulation of mineralised nodules.CONCLUSION:This study indicated that liposomes are an effective carrier for delivering TGF-β1 over time. Liposomal TGF-β1 promoted dentinogenesis and increased mineralisation in hDPSCs. This highlights the potential of liposomal TGF-β1 for future use in dentine-pulp regeneration.CLINICAL SIGNIFICANCE:Liposomal TGF-β1 may be used as a synergist for promoting dentine-pulp regeneration of immature permanent teeth or as a pulp capping agent for inducing reparative dentine formation.

牙齿全脱出即刻损伤牙周膜,治疗重点在于恢复牙周膜的形态和功能.组织工程技术是一种应用种子细胞、生长因子、支架材料修复受损组织的技术手段,为牙周膜再生提供了新的方法.文章就近年来全脱出牙齿牙周膜再生治疗中无细胞性组织再生和细胞性组织再生的研究及应用进展做一综述.

目的 研究不同浓度转化生长因子β1(TGF-β1)促进人牙髓干细胞(hDPSCs)成纤维分化的作用.方法 利用含有不同浓度(1、5、10、20ng/mL)TGF-β1的细胞培养基培养hDPSCs,分别在第1、3和7天时检测细胞增殖情况;在第7和14天时,采用RT-PCR方法检测成纤维相关因子[Ⅰ型胶原蛋白(Collagen Ⅰ)、纤连蛋白(Fibronectin)、骨膜蛋白(Periostin)和α平滑肌肌动蛋白(α-SMA)]的表达情况.结果 MTT结果显示,第7天时,TGF-β1(1 ng/mL和5 ng/mL)可明显促进hDPSCs增殖.RT-PCR结果表明:第7 d时,1ng/mL组、5 ng/mL组和10 ng/mL组Collagen Ⅰ的表达水平分别为对照组的8.2倍、9.3倍和8.1倍,α-SMA的表达水平分别为对照组的6.2倍、6.7倍和5.8倍.5 ng/mL和10 ng/mL组的Periostin表达水平相近,约为1 ng/mL和20 ng/mL组的3.2倍和1.8倍(P＜0.05).第14天时,各实验组的成纤维相关因子表达水平均下降,但仍高于对照组.结论 TGF-β1可以促进hDPSCs的成纤维分化,浓度为10ng/mL时效果最明显.

BACKGROUND: A tooth can be led to lose viability, split easily and miss immune defensive response by pulpitis and pulp necrosis. Determining how to achieve dental pulp regeneration has become a research focus in dentistry. The physicochemical properties and biocompatibility of scaffold materials are crucial for proliferation and differentiation of stem cells. OBJECTIVE: To study whether a gelatin scaffold can induce dental pulp stem cells to differentiate into fibroblasts.METHODS: Gelatin scaffolds at different concentrations were prepared by electrospinning method. The surface morphology and physical properties of gelatin scaffolds were tested by using scanning electron microscope and tensile tests. The human dental pulp stem cells (hDPSCs) were seeded on the scaffolds and the cell proliferation and fibrogenic differentiation were tested using MTT and RT-PCR. RESULTS AND CONCLUSION: The fiber diameter of the 7.5% gelatin scaffold was (2.02±0.36) μm, and it was increased to (3.15±0.52) μm after cross-linking. In the 15% gelatin scaffold, fiber bonding was detected and strengthened until the emergence of flat structures after cross-linking. Both 7.5% and 15% gelatin scaffolds could promote the adhesion and growth of hDPSCs. On day 7, the cell number on the 7.5% gelatin scaffold was significantly higher than that on the 15% gelatin scaffold (P < 0.05). The levels of Collagen I, α-SMA, Periostin and Fibronectin were also higher in the 7.5% gelatin scaffold than in the 15% gelatin scaffold (P < 0.05). In conclusion, 7.5% gelatin scaffold is more beneficial to the proliferation and fibrogenic differentiation of hDPSCs.

目的 研究人根尖牙乳头干细胞(stem cells from apical papilla,SCAP)对小鼠脾脏来源的T淋巴细胞增殖能力的影响以及可能的机制,为揭示SCAP免疫调节性能的具体作用机制奠定基础.方法 原代分离培养人SCAP和小鼠脾脏来源T淋巴细胞.分为两个实验组,即SCAP与T淋巴细胞直接接触共培养组和transwell共培养组,以单独培养的T淋巴细胞作为对照组,流式细胞术检测T淋巴细胞增殖率.结果 在SCAP和T淋巴细胞共培养体系中,细胞直接接触共培养组T淋巴细胞的增殖率较对照组和transwell共培养组均明显降低,差异具有统计学意义(P＜0.05);transwell共培养组T淋巴细胞的增殖率与对照组的差异无统计学意义(P＞0.05).结论 人SCAP主要通过细胞间的直接接触作用抑制T淋巴细胞的增殖,进而发挥其免疫调节性能.

Objective To study the mechanism of periodontal tissue repair of transplanted tooth by analyzing the imaging and histological changes of autogenous transplanted tooth in Beagle dog.Methods For a 8-months-old beagle,the left mandibular premolar region was used as receptor region for autologous tooth transplantation of anterior teeth.X-ray examination was done after operation to observe the periodontal healing of transplanted teeth.Results X-ray at one month after operation showed that the No.1 tooth (left mandibular second premolar) has a narrowed periodontal gap,a small periapical radiolucency and external resorption at tooth neck;No.2 tooth (the left mandibular first premolar) has a internal resorption in the upper 1/3 root canal.Two-month post-operative X-ray examination indicated the periodontal healing of transplanted teeth was perfect.The external resorption of No.1 tooth enlarged and internal resorption of No.2 tooth remained the same.HE staining results showed that new fibrous bundle was formed at the root tip.A large number of lymphocytes and some plasmocytes exited at the tooth neck,pulp cavity and root tip.Conclusion Autogenous tooth transplantation can achieve good periodontal membrane healing.It is important to reduce the mechanical damage to tooth neck while pulling out the teeth.The timing of the dental pulp treatment after transplantation is one of the key elements to reduce postoperative complications.

组织工程技术是一项利用生物替代材料修复受损组织的技术,广泛应用于组织再生,也为口腔牙周膜再生提供了新的方法.文章就近年来牙周膜再生治疗中关于支架材料、生长因子、种子细胞等组织工程技术的研究及应用进展做一综述.

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.

Objective:To evaluate and analyze the methods of bilingual teaching and test results in the subject of pediatric dentistry. Methods:Undergraduates were taught bilingually,and a questionnaire survey was done after that. Then the items were evaluated,and data were statistically analyzed. Results:The students'total score,whether had passed CET-6,and understanding in class were corre-lated with the English test scores. Conclusions:Carrying out bilingual teaching of pediatric dentistry in undergraduates contributes to improve students'professional English,learning interest,self-learning ability and other aspects.

Objective: To find the metastasis-related genes in small cell lung cancer(SCLC),and to investigate the mechanism of SCLC metastasis.Methods: Laser capture microdissection(LCM) and fluoro-differential display reverse transcriptase polymerase chain reaction(fluoro-DDRT-PCR) were performed to screen differentially expressed gene fragments between primary SCLC and metastatic lymph nodes.The sequences of gene fragments were subsequently analyzed and compared to known sequences in Genbank.Results: Twenty-four cDNA fragments(expressed sequence tags,ESTs) which differentially expressed in primary SCLC and metastatic lymph nodes were isolated by using fluoro-DDRT-PCR.Three of these ESTs were cloned,and the sequencing analysis of these clones showed that they were novel gene fragments which had no homology with known genes in GenBank.The expression rate of L_(1)gene [CM(5:46]fragment which located near tumor suppressor gene PTEN in primary SCLC was significant higher than that in metastatic lymph nodes(P0.05).[WT5HZ]Conclusion: The gene expression is different between primary SCLC and the metastatic lymph nodes.These 3 novel gene fragments may be candidates of SCLC metastasis-related genes.The results of this study may provide novel points of therapeutic intervention for SCLC.