再生的牙周组织在正畸压应力下破骨相关因子表达的研究

目的 研究应用改良的双相磷酸钙(biaphasic calcium phosphate,BCP)复合骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs)行犬牙周组织再生后,对再生的牙周组织施加正畸压应力,比较与健康牙周组织受力后破骨相关因子表达的异同,从而探讨牙周再生后进行正畸牙移动的可行性。方法 取6只成年雄性比格犬,拔除其双侧上下颌第一前磨牙,随机分为1周组、2周组和4周组,每组2只犬,实验组于每只犬右上、左下象限第二前磨牙牙根的近中侧制造牙周缺损,并将体外培养的犬BMSCs与BCP的共培物植入缺损区,牙周再生20周后施加正畸力,以1.47 N左右的力值拉第二前磨牙向近中方向移动;以自身为对照,另两象限交替作为牙周再生术后加力0周组和空白对照组。分别于加力1周、2周及4周后处死2只比格犬并取组织块。通过Real-Time PCR及Western-Blot印迹法检测破骨相关因子活化T细胞转化因子-1（NFATc-1）和组织蛋白酶K（Cath-K）的表达。结果 实验组NFATc-1和Cath-K的mRNA和蛋白表达趋势一致:从0周到2周呈上升趋势,2周至4周下降,但仍高于0周时;实验组与对照组阳性表达情况无明显差异（P>0.05)。结论 再生的牙周组织中破骨细胞相关因子的表达情况及变化趋势与正常牙周组织相似,应用改良的BCP用于牙周组织缺损的再生及再生后的正畸牙移动是可行的。     

牙槽骨缺损修复对牙齿移动影响的动物实验

目的了解大鼠牙齿在牙槽骨缺损修复区的移动情况。方法选择40只大鼠，造成一侧牙槽骨缺损，填入45％二氧化硅、24．5％氧化钠、24．5％氧化钙和6％五氧化二磷，作为修复侧，另一侧作为对照侧。术后14周用0．39N力牵引双侧第一磨牙近中移动。配对t检验比较牵引8周后双侧磨牙的移动距离和牙周膜宽度。结果36只大鼠两侧第一磨牙的平均移动距离、牙周膜宽度的差异均无统计学意义（P〉0．05）。结论牙槽骨缺损修复侧可以进行正畸牙齿移动，修复侧的牙齿移动距离及牙周组织受正畸力后的改建情况，均与对照侧无显著差别。     

正畸力下牙周膜干细胞的改变及其作用机制的研究进展

<正>牙周膜干细胞（periodontal ligament stem cells,PDLSCs）是从牙周膜中分离获得的一类具有自我更新能力、增殖能力、多向分化潜能和免疫调节能力的干细胞，是牙周组织的维持、改建及再生的重要细胞源[1,2]。正畸牙移动（orthodontic tooth movement,OTM）是指在正畸力作用下，牙周组织发生适应性改建，进而产生牙齿移动的过程[3]。OTM的过程中同时伴随有成骨、破骨两种活动，二者共同调控着牙周组织的改变，而PDLSCs作为牙周组织中的主要干细胞，在这一过程中发挥主要作用。     

应用牙周膜干细胞—牙囊干细胞复合细胞膜片同种异体移植修复比格犬牙周组织缺损的研究

目的 拟构建比格犬牙周缺损模型,观察牙周膜干细胞—牙囊干细胞复合细胞膜片修复牙周组织缺损的效果.方法 分离培养比格犬牙囊干细胞、牙周膜干细胞,制备牙囊干细胞细胞膜片、牙周膜干细胞细胞膜片以及以上2种细胞的复合细胞膜片,将膜片混合支架材料同种异体植入成年雄性健康比格犬牙周缺损模型,对照组只植入支架材料.分别于移植后1周、2周、4周、6周、8周、12周检测探诊深度、牙龈退缩、附着丧失情况.12周后观察分析牙周再生的组织形态学变化.结果 牙周临床检查及组织学形态学分析显示,3个膜片移植组牙周再生效果较对照组效果明显,其中复合细胞膜片移植组明显高于其余两个单一膜片移植组(P<0.05).结论 牙周膜干细胞—牙囊干细胞复合膜片同种异体移植更有利于修复比格犬牙周缺损.     

牙周膜牵引成骨不同牵引速率移动牙张力侧牙周组织改建研究

目的探讨牙周膜牵引成骨中不同牵引速率移动牙张力侧牙周组织改建，及在牵引频率一定情况下的最适牵引速率．为临床应用提供客观理论依据。方法将7只犬的下颌左右两侧随机分组，按每天牵引速率分为0．2、0．6、1．0mm／d三组和常规对照组、空白对照组。实验组固定牵引频率1次／天，每组分别以不同的牵引速率（0．2、0．6、1．0mm／d）进行牵引，牵引1周后维持3d。常规对照组使用镍钛螺旋拉簧对移动牙施力1周。取材行HE、Mallory’s三色染色．观察移动牙张力侧牙周组织改建。结果0．2mm／d组和0．6mm／d组移动牙张力侧牙周膜显著增宽．均显著宽于常规对照组，牙周膜细胞丰富，血管扩张。有明显新骨生成；1．0mm／d组牙周纤维断裂，组织水肿，未见新骨的生成。结论与常规对照组相比，牙周膜牵引成骨能促进牙周组织改建．加快牙齿移动。但是牙周膜存在承载极限，在其极限范围内，牙周膜改建随牵引速率的增加更加活跃．超过其极限范围．牙周膜改建停止．出现永久性损伤。     

组织工程修复区早期牙移动压力侧牙周组织的改建

目的: 探讨牙槽骨组织工程修复区内早期牙移动时压力侧的牙周改建情况,为组织工程技术在正畸中应用的安全性和可行性提供实验依据。方法: 选取30只新西兰大白兔,通过拔除下颌第一磨牙并扩大拔牙窝,建立双侧牙槽骨的超临界骨缺损,分别以实验组骨髓间充质干细胞（bone marrow mesenchymal stem cells,BMSCs）与颗粒型多孔β磷酸三钙（beta-tricalcium phosphate,β-TCP）支架复合构成的组织工程骨和对照组单纯β-TCP支架进行右侧和左侧骨缺损修复。术后8周,选取6只兔进行植骨区取材,评价2组的成骨效果。对剩余兔进行下颌两侧第二磨牙加力,近中向牵引4周。分别在加力后的第1、2、3、4周各处死6只动物,测量牙移动距离并制作组织学切片,通过H-E染色观察牙周组织变化,抗酒石酸酸性磷酸酶染色法计数压力侧破骨细胞数目。采用SPSS 19.0软件包对数据进行统计学分析。结果: 植骨术后8周,实验组成骨效果优于对照组。牵引4周后,正畸牙在实验组牙槽骨修复区内的移动量大于对照组。牵引第2、3、4周时,实验组移动牙压力侧的破骨细胞数量均高于对照组,差异具有统计学意义。结论: BMSCs复合β-TCP支架能够良好地修复牙槽骨缺损,邻牙在组织工程修复区内早期移动时,再生的牙周组织改建活跃,有加速牙移动的趋势。     

自体牙周膜细胞移植对狗牙周组织再生的影响

目的　对应用自体牙周细胞移植结合e PTFE膜引导的牙周组织再生的动物实验进行评价。方法　将 6只成年狗的 36颗牙分为实验组和对照组 ,每组 18颗牙。在人工制造的牙周缺损中 ,进行体外培养的自体牙周细胞移植结合GTR法为实验组 ,单纯应用GTR法为对照组。 6周后切片行牙周组织学观察。结果　实验组新生牙槽骨、牙周膜组织及牙骨质的修复再生效果明显好于对照组 (P <0 0 5 ) ;实验组牙槽骨再生高度平均为 (4 0 0± 0 13)mm ,对照组为 (3 0 9± 0 2 8)mm。结论应用自体牙周膜细胞移植结合e PTFE膜引导牙周组织再生可促进狗牙周组织的再生     

正畸力作用初期牙周组织内P75的表达变化

目的:研究正畸力作用下牙齿移动早期牙周膜组织内P75受体的表达变化。方法:制备大鼠实验性牙齿移动动物模型,采用免疫组织化学的方法检测牙周膜组织中P75的表达。结果:正畸力作用下牙齿移动早期牙周组织内P75表达先升高后降低,于加力后3d表达最高。结论:P75在牙齿移动早期牙周组织改建中起作用,可能参与了牙周组织早期炎症反应和疼痛反应。     

正畸力作用下大鼠牙周组织中骨桥蛋白的表达

目的：观察SD大鼠正畸牙齿移动过程中牙周组织内骨桥蛋白（osteopontin,OPN）的表达,探讨OPN在正畸牙齿移动过程及成骨方面的作用和机制。方法：选用6～8周龄雄性SD大鼠40只,以左侧上颌第一磨牙为实验组,右侧上颌第一磨牙不加力为对照组,通过自制的加力装置牵引移动大鼠的磨牙,分别在加力后8h、24h、3d、7d处死实验动物,即刻取上颌骨制备组织标本,通过免疫组织化学方法检测SD大鼠牙周组织中OPN的表达。结果：实验组大鼠牙周膜中张力侧OPN表达明显高于对照组,3d、7d组差异有统计学意义（P〈0.01）。结论：在正畸治疗牙齿移动过程中,OPN参与牙周组织的改建并与新骨的形成相关。     

前列腺素E_2加速兔牙移动的实验研究

本实验选用家兔16只,分为两组。一组注射前列腺素 E_2(PGE_2)。一组为对照组。通过对PGE_2组与对照组两组牙齿移动距离的测量和牙周组织变化的观察表明:PGE_2可以加速正畸牙齿移动,PGE_2组牙周组织未见异常改变。本文还对正畸力所致的牙周膜变性、牙槽骨吸收与修复进行了探讨。     

The effects of the Le Fort I osteotomy on the periodontium.

Two age-matched populations of equal size (n = 40), one having orthodontic therapy and the other combined orthodontic therapy and orthognathic surgery, were evaluated for their periodontal status 1 to 10 years posttherapy. The parameters investigated were plaque index, gingival index, tooth mobility, width of keratinized tissue, probing depth, gingival recession, and attachment level. No significant differences were found (P less than .05). Within the surgery group, patients with maxillary osteotomies segmentalized between the central incisors (n = 11) and between the canines and second premolars (n = 12) were evaluated using the same parameters and compared with their nonsegmental counterparts. No significant differences were found for patients with osteotomies segmentalized between the central incisors. However, a statistically significant increase in probe depth and loss of attachment level of up to 0.3 mm was found at the sites of osteotomies segmentalized between the canine and second premolar (P less than .05). This difference was not considered clinically significant.     

Effect of lipopolysaccharide on cell proliferation and vascular endothelial growth factor secretion of periodontal ligament stem cells

PurposePeriodontal ligament stem cells (PDLSCs) have considerable potential for use as a means of achieving periodontal regeneration due to their noteworthy proliferative properties and secretory functions. In particular, PDLSCs secrete vascular endothelial growth factor (VEGF) which enhances angiogenesis and osteogenesis. The resulting repair and development of blood vessels and hard tissues which would occur in the presence of these cells could be central to an effective periodontal regeneration procedure.The bacterial biofilm of tooth surface related to the periodontium might provide either an inhibition or a stimulus to different factors involved in a regenerative process. Cell culture experiments have been investigated in vitro by adding lipopolysaccharide (LPS) to the culture medium but the effect of various concentration of LPS in these circumstances has not been investigated. Therefore, this study aimed to investigate the effect of LPS concentrations on proliferation of PDLSCs in vitro and on their secretion of VEGF.Materials and methodsPDLSCs were treated with 0, 5, 10 and 20 µg/mL of Escherichia coli LPS. At 48 and 96 h, total cell numbers of control and LPS treated PDLSCs were counted by haemocytometer under a microscope. The VEGF concentration in the conditioned media of the PDLSCs was measured by ELISA.ResultsRate of cell proliferation of PDLSCs decreased significantly in all LPS treated groups at both 48 h and 96 h except for the group treated with 5 µg/mL of LPS at 48 h. At both 48 and 96 h, VEGF secretion from PDLSCs was reduced significantly at all three LPS concentrations. There was no statistically significant difference in cell proliferation and the amount of VEGF secretion of PDLSCs among the groups treated with different LPS concentrations. No statistically significant change was found in cell proliferation of LPS treated PDLSCs over time, whereas VEGF secretion of PDLSCs was found to have increased significantly with time despite the LPS treatment.ConclusionsLPS reduced cell proliferation and VEGF secretion of PDLSCs, suggesting that periodontal pathogens might reduce the capability of PDLSCs in periodontal regeneration. Yet, LPS treated PDLSCs remained viable and VEGF secretion increased significantly over time. Further research is needed to study the potential use of PDLSCs in periodontal regeneration and the relationship of biofilm LPS accumulations.     

大鼠正畸牙移动中牙周组织内STRO-1动态变化的研究

目的:通过观察大鼠正畸牙移动中牙周组织内STRO-1的动态变化,研究大鼠牙周膜干细胞(periodontal ligament stem cell,PDLSC)在正畸牙周组织改建中的作用及表达变化的规律.方法:选用幼年SD大鼠,建立正畸牙移动的模型,分别在加力后1、3、5、7、10、14 d处死动物,制备标本.应用EnVision系统两步法和图像分析进行半定量分析.结果:正常大鼠牙周组织中STRO-1表达较低.STRO-1在加力组牙周膜中的表达与对照组比较,差异有显著性,在正畸牙移动过程中STRO-1阳性显色细胞明显增多.结论:STRO-1的表达强度与牙周改建的活跃程度相关,揭示了在正畸力作用下牙周组织改建的可能机制和牙周膜干细胞的作用.     

构建一种新型牙周膜牙囊复合细胞膜片的研究

目的：拟构建一种牙周膜牙囊复合细胞膜片,并比较其与单一膜片的性能差异,以期寻找一种更加优越的牙周缺损修复材料。方法：将第三代牙周膜干细胞及牙囊干细胞直接混合共同培养,将牙周膜牙囊混合细胞、牙周膜干细胞及牙囊干细胞分别制备成细胞膜片,应用HE染色,扫描电镜比较三种膜片形态学差异,应用茜素红染色,RT—PCR比较三种膜片成骨能力差异。结果：扫描电镜结果显示,牙囊牙周膜混合细胞膜片分泌更多的细胞外基质。HE染色结果也显示牙囊牙周膜混合细胞膜片细胞层数更多,基质分泌量更大。同时,牙囊牙周膜混合细胞膜片AIJP、Runx2、OCN表达显著高于单一细胞膜片。成骨诱导21天后,茜素红染色结果显示,与单一细胞膜片相比,牙囊牙周膜混合细胞膜片染色更深。结论：牙周膜牙囊复合细胞膜片较单一细胞膜片,细胞层数更多,基质分泌量更大,骨向分化能力更强,为牙周再生提供了新的思路。     

The effect of orthodontic treatment on periodontal bone support in patients with advanced loss of marginal periodontium

Loss of periodontal bone support was examined in 24 patients orthodontically treated for pathologic tooth migration in one jaw. Prior to orthodontic realignment of the front teeth, the patients had received periodontal treatment. Active appliance therapy was not given until inflammation was eliminated and the patients demonstrated a high level of oral hygiene. A 0.020-inch spiral wire was bonded to each adjacent realigned tooth for retention. The levels of marginal bone of the front teeth in the treated and untreated jaws were measured in percentage of "maximum bone height" on periapical radiographs made before and after treatment. Relapse was evaluated from study models. Mean averaged loss of periodontal bone from the period before to after orthodontic treatment was 4.94% (SD 4.03, P less than 0.001) and 2.69% (SD 3.66, P less than 0.001) of the treated and untreated front teeth, respectively. The mean difference in averaged loss between treated and untreated front teeth was 2.24% (SD 3.28, P less than 0.01). The majority of the sites showed little or no loss. Maximum loss (35%) was observed in one site only. No association was found between initial bone loss and bone loss during orthodontic treatment. Spaces from 0.1 to 1.8 mm opened up adjacent to the retainer in seven patients. Relapse within the retained segment was associated with failures of the retainer. Of the 19 patients who had been in retention for more than 4 months (mean 16.0, SD 12.1), ten failures were recorded in nine patients. The failure mode was loosening of one or two teeth between wire and composite.     

应用正畸移动装置在牵引成骨新成骨中移动牙的动物模型的建立

目的探讨应用自制正畸移动装置在牵引成骨新成骨中移动牙的方法的可行性,建立动物模型,为临床应用提供客观理论依据。方法将六只成年（12～15月龄）雄性小尾寒羊（绵羊）的下颌两侧随机分组,随机选择一侧为实验组,另一侧为对照组。实验组按照骨成熟期分为一周组、两周组、三周组、四周组（非成熟骨组）和半年组、一年组（成熟骨组）。对照组分为常规对照和空白对照。非成熟组对侧为常规对照,成熟骨组对侧为空白对照。实验组在下颌第一双尖牙的近中牙槽嵴位置行手术骨皮质切开,放置牵引成骨器,术后5天开始牵引成骨,每12小时牵引加力一次,1．2mm／d,牵引6天,在第一双尖牙近中形成7．2mm新生骨段;分别在一周、两周、三周、四周和半年、一年后,在第一双尖牙近中约2cm位置牙槽嵴顶植入种植钉作为支抗,使用正畸轻力移动牙齿的方法应用镍钛拉簧牵引第一双尖牙向近中移动,力值约100g（0．98N）,3周后第一双尖牙移入牵引成骨骨段。常规对照组,使用同样正畸方法牵引第一双尖牙向近中移动3周。结果实验组牙齿顺利移动进入牵引成骨骨段,松动度Ⅰ度,局部牙龈红肿、轻度炎症,X线检查示无X尖周病变、无明显牙根吸收。结论使用正畸力在牵引成骨新成骨中移动牙齿的方法切实可行,本研究所建立的动物模型可以应用于后续的研究中。     

Periodontal repair in dogs: evaluation of the natural disease model

Abstract Animal models are frequently consulted for histometric analysis of periodontal reconstructive therapy. Such models include surgical, periodontitis-simulating and natural disease defects in canines or non-human primates. Our studies suggest that homogeneity in defect height is critical for sensitivity of surgical and periodontitis-simulating supraalveolar defect models in discriminating treatment effects. We herein evaluate this model aspect for natural disease defects. Buccal-lingual histologic sections from the 2nd, 3rd, and 4th mandibular premolar teeth (P2, P3, P4) from 6 aged beagle dogs with advanced natural periodontal disease were used. Defect heights from the reduced alveolar bone to the cemento-enamel junction were recorded in central step-serial sections at the buccal and lingual surfaces of the mesial and distal roots for the premolar teeth. Mean defect height, standard deviation and coefficient of variation were calculated for tooth types and jaw quadrants, separately, and for all teeth. Confidence intervals were calculated for teeth in left and right jaw quadrants. Mean defect height and standard deviation for left and right jaw quadrants was 3.6±0.9 and 3.3±0.6 mm for P2. 3.3±.9 and 2.3±0.9 mm for P3, and 3.3±1.0 and 4.5±1.6 mm for P4. respectively. Coefficient of variation for defects for left and right jaw quadrants was 26 and 40%, respectively. Using confidence intervals for mean differences between jaw quadrants, it was determined that a mean treatment effect may be as large as 0.8, 1.1 and 1.9 mm for P2. P3 and P4, respectively, before being detected as statistically significant (p≤0.05, N=6). With the apparent variation in defect baseline, it is suggested that natural disease defects have limited potential in discriminating treatment effects following periodontal reconstructive therapy.     

Apical tooth germ cell-conditioned medium enhances the differentiation of periodontal ligament stem cells into cementum/periodontal ligament-like tissues

Background and Objective: Limitations of current periodontal regeneration modalities in both predictability and extent of healing response, especially on new cementum and attachment formation, underscore the importance of restoring or providing a microenvironment that is capable of promoting the differentiatiation of periodontal ligament stem cells (PDLSCs) towards cementoblast‐like cells and the formation of cementum/periodontal ligament‐like tissues. The aim of this study was to investigate the biological effect of conditioned medium from developing apical tooth germ cells (APTG‐CM) on the differentiation and cementogenesis of PDLSCs both in vitro and in vivo. Material and Methods: Using the limiting dilution technique, single‐colony‐derived human PDLSCs were isolated and expanded to obtain homogeneous populations of PDLSCs. Morphological appearance, cell cycle analysis, bromodeoxyuridine incorporation, alkaline phosphatase (ALP) activity, mineralization behavior, gene expression of cementoblast phenotype and in vivo differentiation capacities of PDLSCs co‐cultured with APTG‐CM were evaluated. Results: The induced PDLSCs exhibited several characteristics of cementoblast lineages, as indicated by the morphological changes, increased proliferation, high ALP activity, and the expression of cementum‐related genes and calcified nodule formation in vitro. When transplanted into immunocompromised mice, the induced PDLSCs showed tissue‐regenerative capacity to produce cementum/periodontal ligament‐like structures, characterized by a layer of cementum‐like mineralized tissues and associated periodontal ligament‐like collagen fibers connecting with the newly formed cementum‐like deposits, whereas control, untreated PDLSCs transplants mainly formed connective tissues. Conclusion: Our findings suggest that APTG‐CM is able to provide a cementogenic microenvironment and induce differentiation of PDLSCs along the cementoblastic lineage. This has important implications for periodontal engineering.