钛种植体与单纯珊瑚及复合BMP珊瑚代用品结合的实验研究

目的　研究单纯珊瑚与复合BMP的珊瑚表面贴附移植后与同期植入的钛种植体形成骨结合的情况。方法　将单纯珊瑚与复合BMP的珊瑚置于去皮质的犬髂骨表面 ,同时植入钛种植体 ,用种植体固定人工骨 ,不同时间取材 ,观察种植体与人工骨的骨结合情况。结果　种植体与单纯珊瑚与复合BMP的珊瑚均可以形成骨结合。单纯珊瑚 12周时 ,种植体与珊瑚之间形成结构不规则的骨界面 ;同时 ,材料有大量的吸收。珊瑚复合BMP时新骨明显增多 ,形成粗的骨小梁 ,骨髓腔变小 ,6周时与种植体之间已经形成基本完善的骨界面 ;且材料总体吸收量较少。结论　天然珊瑚具有良好的生物相容性 ,可以与钛种植体形成骨性结合 ;BMP、珊瑚复合材料植入可以加快成骨 ,延缓吸收。此复合材料可以应用于种植外科     

钛种植体表面改性的现状、问题与发展趋势

钛在生理环境中具有良好的化学稳定性、良好的机械力学性能及良好的生物相容性,是口腔种植的首选材料。理想的种植材料应能在植入后刺激新骨的形成并与骨形成骨性结合,纯钛表面呈生物惰性,不能诱导新骨的形成。因此,植入后如何增强成骨诱导性,加速与骨的骨性结合是钛种植体表面改性的一个重要方向。另外,临床研究表明种植体周围感染是导致种植失败的一个重要因素,因此赋予钛种植体表面持续的抗菌性是钛种植体改性的另一重要方向。     

钛网成形自体颗粒骨修复下颌骨缺损并同期种植的实验研究

目的 观察犬钛网成形自体颗粒骨移植修复下颌骨节段性缺损并同期植入钛种植体后的骨愈合和骨结合情况.方法 5只Beagle犬,一侧下颌骨制备长40 mm的节段性缺损;钛网成形修复下颌骨缺损.将切除后的下颌骨和自体髂骨剪成直径约2mm颗粒,骨皮质、骨松质体积比3∶1混合,紧密充填在钛网内,将2枚纯钛种植体埋置于颗粒骨内,术后6个月处死动物.用下颌骨X线片、组织学切片、扫描电镜以及能谱分析观察钛网内颗粒骨愈合以及种植体骨结合的情况.结果 钛网成形自体颗粒骨移植重建后的下颌骨外形满意,功能正常、颗粒骨成骨良好、结构优良,未见明显骨吸收.同期植入的种植体能够与周围骨组织形成良好的骨结合,并有促进邻近骨组织结构优化的趋势.结论 钛网成形自体颗粒骨移植是一种修复下颌骨节段性缺损的好方法,当修复后下颌骨形态良好、骨质优良、骨量充足时可以同期植入种植体.     

提升钛种植体表面生物活性的策略

钛及钛合金因具有良好的生物相容性,已被广泛应用于牙种植领域.然而,至今仍有关于种植体植入后脱落的报道,其中骨整合及生物力学稳定性不够是其主要原因之一.从材料本身而言,钛及钛合金属于生物惰性材料,缺乏生物活性,这恰恰是影响骨生成和骨整合过程的关键.因此,近年来,通过各种钛表面改性技术试图去提升钛种植体的成骨活性和骨整合能力已成为研究的热点.本文将着重针对如何提升钛种植体表面的生物活性,谈谈相应的策略.     

复合牛骨形成蛋白多孔中空种植体成骨效应的研究

目的　利用激光扫描共聚焦显微镜(LSCM)观察牛骨形成蛋白复合种植体成骨效应。方法　将天然提取的牛骨形成蛋白(bBMP)与多孔中空钛种植体相复合形成人工复合种植体,植入狗下颌骨,并设同等规格的实心柱状钛种植体及不复合bBMP的多孔中空柱状钛种植体植入狗下颌骨为对照组。应用三色荧光标记LSCM观察复合种植体周围骨整合情况。结果　实验组复合种植体在各时期成骨能力和成骨量均明显优于对照组。结论　复合种植体可诱导早期、大量、较持久的成骨;LSCM对种植体周围成骨行为进行观察是一种准确、有效的手段。     

紫外线处理微弧氧化种植体的早期成骨研究

目的研究C波段紫外线(ultraviolet C,UVC)处理的微弧氧化(micro-arc oxidation,MAO)纯钛种植体植入兔胫骨后的早期成骨方式。方法实验分2组,MAO组和UVC-MAO组。MAO组将医用纯钛种植体经微弧氧化处理后植入新西兰大白兔胫骨。UVC-MAO组将医用纯钛种植体经过微弧氧化处理后,用15 W UVC灭菌灯对钛种植体照射48 h,经过25.0 kGyγ射线消毒后植入新西兰大白兔胫骨。2周后取出胫骨,用锥形束CT观察种植体表面成骨情况;制作胫骨硬组织切片,并以亚甲基蓝-酸性品红染色,光学显微镜观察两组种植体的成骨方式。结果 MAO组可见靠近种植体骨环底端的为成骨细胞及软组织,无任何骨组织,骨环斜面有从周围成熟骨生长的骨组织及类骨质,但所有组织与种植体表面均有一定距离,而非密切接触材料表面。UVC-MAO组可见种植体骨环底端及骨环斜面表面紧密接触类骨质及成骨细胞,还有已经分化的新生骨组织;所有组织与种植体表面紧密接触,无间隔。结论紫外线处理微弧氧化后的种植体,更有利于成骨细胞粘附于种植体表面,形成新生骨质并紧密贴附于种植体表面,骨环周围成熟骨质同时向种植体生长,有利于种植体早期的接触成骨。     

纳米羟基磷灰石修复种植体周围骨缺损的实验研究

目的:探讨纳米羟基磷灰石材料在种植修复中的作用.方法:将纳米羟基磷灰石植入钛种植体周围的骨缺损区,观察种植体与骨界面的结合形式和程度.结果:纳米羟基磷灰石修复钛种植体骨缺损处实现良好的骨结合.结论:纳米羟基磷灰石材料的使用在实现钛种植体与周围健康骨组织的骨结合过程中起着重要的作用.     

钛种植体表面早期成骨方式的动物模型研究

目的：研究适合用于观察钛种植体表面早期成骨方式的动物模型。方法对原有的种植体植入模式进行改进,使种植体植入动物体内的初始状态为种植体外螺纹贴于种植窝骨壁,种植体螺纹内部与周围骨壁保持一定距离。4只Beagle犬下颌骨延期植入20枚种植体,植入后2周和4周分别处死2只Beagle犬,对标本进行组织学观察。结果4只Beagle犬手术创口均达到一期愈合,未出现种植体松动。组织学观察可见种植体表面新骨生成,种植体周围骨壁新骨生成,可清楚地观察到新骨生成方向,可观察到接触成骨和距离成骨。结论本研究创建的动物模型可以清晰地观察钛种植体表面早期成骨的方式,也可客观地反映种植体表面性能对其表面早期成骨方式的影响。     

种植体骨界面组织形态学研究方法探讨

目的:探讨利用Leitz-1600型锯割切片机及骨磨片技术进行种植体骨结合状况的组织学研究方法.方法:选取植入种植体的颌骨或其他部位的骨组织,经过X线定位、塑料包埋、锯割切片机分切、手工磨片及特殊染色等组织学手段,考察种植体骨结合情况,以及植入骨再生材料的成骨情况.结果:植入种植体的骨组织经过完善的组织学处理后,采用手工磨片可以磨制30μm～50μm的骨种植体磨片,并能清楚地观察到种植体骨结合的状况,以及骨再生材料成骨的变化过程.结论:塑料包埋,手工磨片,以及特殊染色等组织学方法,可以成为研究种植体骨结合及其他与种植体相关研究的重要手段.     

两种钛种植体与骨结合界面的组织学研究

目的　对两种表面形态不同的钛种植体在不同种植时期骨结合界面情况进行研究。方法　在恒河猴下颌磨牙区分期分别植入CDIC和ITI-TPS钛种植体,采用同体对照的方法,对两种种植体与骨结合界面情况进行组织学观察。结果　口腔检查未见种植体松动及周围组织明显炎症表现。各期种植体骨界面X线影像均未见明显透射暗影,仅种植1个月的CDIC种植体颈部见少量角形吸收。光镜和扫描电镜观察见种植1个月后两种种植体骨界面有少量骨形成;1~3个月ITI-TPS种植体界面骨形成较明显,成骨量统计分析,差异有显著性;种植后1年,两者未见明显差别。结论　无载荷条件下,种植体植入后1~3个月内,ITI-TPS种植体表面骨结合形成优于CDIC种植体。随植入时间的增加,两种种植体均形成良好的骨性结合界面。     

Mineral trioxide aggregate inhibits osteoclastic bone resorption

Mineral trioxide aggregate (MTA), a commonly used endodontic repair material, is useful for both basic and clinical research, and the effect of MTA on osteoblast differentiation has been well-defined. However, the effects of MTA on osteoclastic bone resorption are not fully understood. Hence, the aim of this study is to examine the effect of MTA solution in the regulation of osteoclast bone-resorbing activity using osteoclasts formed in co-cultures of primary osteoblasts and bone marrow cells. MTA solution dose-dependently reduced the total area of pits formed by osteoclasts. The reduction of resorption induced by 20% MTA treatment was due to inhibition of osteoclastic bone-resorbing activity and had no effect on osteoclast number. A 20% MTA solution disrupted actin ring formation, a marker of osteoclastic bone resorption, by reducing phosphorylation and kinase activity of c-Src, and mRNA expressions of cathepsin K and mmp-9. A high concentration of MTA solution (50%) induced apoptosis of osteoclasts by increasing the expression of Bim, a member of the BH3-only (Bcl-2 homology) family of pro-apoptotic proteins. Taken together, our results suggest that MTA is a useful retrofilling material for several clinical situations because it both stimulates osteoblast differentiation and inhibits bone resorption.     

唑来膦酸胶原膜对骨代谢细胞的影响初探

目的 通过研究唑来膦酸胶原膜对骨代谢细胞的影响,探讨该载药膜是否具有抑制局部骨吸收、促进局部骨形成的能力.方法 分别以双层胶原膜(Bio-Gide(R))和单层胶原膜(BME-10X(R))为载体,吸附不同浓度唑来膦酸(zoledronic acid,ZA),制备唑来膦酸胶原膜,分别命名为BG0、BG1、BG2、BG3组和BM0、BM1、BM2、BM3组(BG代表双层胶原膜,BM代表单层胶原膜,0、1、2、3分别代表唑来膦酸浓度为0、1×10-4、1×10-3、1×10-2 mol/L),设置无胶原膜组为空白对照组.通过离体细胞培养,评价唑来膦酸胶原膜对破骨细胞和成骨细胞的影响.结果 唑来膦酸胶原膜与破骨细胞体外共培养显示:培养第7大,BG1、BG2、BG3、BM1、BM2、BM3组骨吸收陷窝面积百分比分别为18.80%、14.75%、14.28%、20.51%、15.77%、15.12%,明显低于BG0(31.53%)和BM0(32.22%,P＜0.05),载药量越高,其抑制效果越强.唑来膦酸胶原膜与成骨细胞体外共培养显示:培养第7天,BG2组增殖指数(7.00)明显高于BG0(6.90);培养第4天,BG2、BG3、BM2、BM3组碱性磷酸酶表达(分别为154.67、154.33、155.33、152.00 U/g)明显高于BG0(129.33 U/g)和BM0(127.67 U/g,P＜0.05).结论 唑来膦酸胶原膜可同时具有抑制骨吸收和促进成骨细胞增殖的能力.

Abstract：

Objective To develop zoledronic acid (ZA)-loaded collagen membranes, and to study its effect on osteoclast and osteoblast so as to investigate whether ZA-loaded membranes can inhibit local bone resorption and promote bone formation. Methods ZA-loaded double-layer (Bio-Gide(R)) and singlelayer(BME-10X(R)) collagen membranes were prepared and divided into eight groups according to the concentrations of ZA in the membrane, namely Group BG0, BG1, BG2, BG3 and BM0, BM1, BM2, BM3 (BG refers to Bio-Gide(R), BM refers to BME-10X(R), 0, 1,2, 3 refer to the concentrations of ZA, 0, 1 ×10-4, 1 × 10-3, 1 × 10-2 mol/L respectively). Blank control group was set without using collagen membrane. The effects of ZA-loaded membranes on osteoclast and osteoblast were assessed using in vitro cell culture models. Results In vitro coculture of ZA-loaded membrane with osteoclast for seven days showed that the percentage of bone resorption area in BG1, BG2, BG3, BM1, BM2, BM3 were 18.80%,14.75%, 14.28%, 20.51%, 15.77%, 15.12% respectively, which were lower than that in BG0 (31.53%) and BM0(32.22%, P ＜0.05), and the higher ZA loading was, the stronger its inhibition to osteoclast was. In vitro coculture of ZA-loaded membrane with osteoblast for four days indicated that alkaline pbosphatase(ALP) activities in BG2 (154.67 U/g), BM2 (154.33 U/g), BG3 (155.33 U/g), BM3 (152.00 U/g) were higher than that in BG0(129.33 U/g) and BM0(127.67 U/g, P ＜ 0.05). What's more, results from seven-day coculture showed that proliferation index in BG2(7.00) was higher than that in BG0(6.90). Conclusions ZA-loaded collagen membrane can not only inhibit osteoclastic bone resorption but also improve proliferation of osteoblast.     

Bisphosphonates and periodontics: potential applications for regulation of bone mass in the periodontium and other therapeutic/diagnostic uses

Bisphosphonates are widely utilized in the management of systemic metabolic bone disease due to their ability to inhibit bone resorption. Recently, new uses of this unique class of pharmacological agents have been suggested. Given their known affinity to bone and their ability to increase osteoblastic differentiation and inhibit osteoclast recruitment and activity, there exists a possible use for bisphosphonates in the diagnosis and management of periodontal diseases. These bone-specific properties could also provide an interesting management strategy to stimulate osteogenesis in conjunction with regenerative materials around osseous defects and may also result in the promotion of bone formation around endosseous implants. The objective of this article is to review the scientific evidence regarding the potential applications of bisphosphonate drugs in the therapeutic management of periodontal diseases. Moreover, the mechanism of action and the pharmacology of these drugs will be reviewed. Finally, the potential role of bisphosphonates regarding their potential to accelerate bone formation, in addition to their usual uses for inhibition of bone resorption, is discussed.     

Osteoclast activity around loaded and unloaded implants: a histological study in the beagle dog

The mechanisms of bone loss around dental implants are poorly understood. The osteoclast is the most important bone-resorbing cell. Humoral factors seem able to stimulate the differentiation of osteoclasts from mononuclear phagocytes. Bacterial lipopolysaccharides seem to be directly involved in inflammatory bone loss by stimulation of the survival and fusion of preosteoclasts. Excessive load seems to be able to cause bone loss. The aim of this paper was to evaluate the presence and number of osteoclasts in peri-implant bone in control (unloaded) and test (loaded) implants in order to determine if loading per se could be a contributing factor in peri-implant bone resorption. Forty-eight implants were inserted in the mandibles of 4 beagle dogs. After 3 months, a prosthetic superstructure was inserted on 24 implants, whereas in 24 implants only the healing screws were positioned. Twenty-four implants (12 test and 12 control) were retrieved at 6 months, and 24 implants (12 test and 12 control) were retrieved at 12 months. All implants were osseointegrated. The number of osteoclasts found in the crestal bone in the first 3 mm from the implant surface was evaluated. The mean number of osteoclasts were the following: control implants (6 months), 5.66 +/- 0.81; control implants (12 months), 2.55 +/- 1.05; test implants (6 months), 5.25 +/- 1.55; and test implants (12 months), 2.5 +/- 1.0. No statistically significant differences were observed between the control and test implants. According to our data, loading does not seem to have a relevant importance on the osteoclast activation in peri-implant bone.     

白细胞介素-6与牙周组织的改建

白细胞介素-6是一种来源广泛的多功能细胞因子,与牙周组织改建有密切的关系。咬合力废用和代偿,均诱导牙周膜细胞和牙槽骨成骨细胞表达IL-6蛋白及mRNA明显增加。IL-6通过作用于破骨细胞前体来促进骨吸收,也能够抑制牙周膜细胞的生长,从而影响组织的修复和代谢功能;它还能促进成骨细胞的分化,促进骨的形成,是牙周组织改建的重要细胞因子。     

Roles of non-canonical Wnt signaling pathways in bone resorption

Background

Wnt is a cytokine involved in the development and homeostasis of various organs. In 2001, low-density lipoprotein receptor-related protein 5 (LRP5) was identified as the gene responsible for osteoporosis pseudoglioma syndrome and regulation of bone mass. Since LRP5 belongs to the low-density lipoprotein receptor family, this finding garnered the attention of researchers in the bone, mineral, and Wnt research fields. The role of Wnt in bone formation and resorption has since been extensively studied. Wnt/β-catenin signals are known to play a role in bone resorption. The activation of these signals in osteoblast lineage cells such as osteoblasts and osteocytes induces the expression of osteoprotegerin and then inhibits osteoclast formation.

Care required when using bisphosphonates in dental surgical practice

Bisphosphonates are pharmacologic compounds characterized by high tropism to bone tissue. They affect bone metabolism by inhibition of osteoclast recruitment, proliferation, differentiation, and function. Because they can reduce bone resorption, bisphosphonates are used mainly for the treatment of osteometabolic conditions. However, the use of bisphosphonates has been associated with the onset of osteonecrosis of the jaws and indication of dental implants. As a result of this, the aim of this study was to present the risks and the care that health professionals should take in cases of surgical procedures such as placement of dental implants in patients who make use of bisphosphonates.     

Appearance of osteoclasts by injections of lipopolysaccharides in rat periodontal tissue

The effect of lipopolysaccharides (LPS) on periodontal tissue was studied in 11-week-old Wistar rats. Four injections of 500 micrograms LPS induced marked osteoclastic alveolar bone resorption, whereas no alveolar bone resorption occurred after four injections of physiological saline. The osteoclast count increased progressively during the four injections of 500 micrograms LPS. After eight injections, however, the osteoclast count fell from the maximum level after four injections, although osteoclasts continued to increase in size and demonstrate an increased number of nuclei. Comparison of the osteoclast number between a series of four injections of 5, 50 or 500 micrograms LPS each revealed a dose-dependent increase. This strongly suggests LPS induction of osteoclastic bone resorption in vivo. Combined use of indomethacin, a prostaglandin synthesis inhibitor, with LPS injections inhibited both the LPS-induced alveolar bone resorption and osteoclast increase, suggesting a possible participation of prostaglandins in osteoclast-mediated bone resorption.     

A histopathological investigation on the effects of the bisphosphonate alendronate on resorptive phase following mucoperiosteal flap surgery in the mandible of rats

BACKGROUND: The present study was designed to examine histopathologically whether local delivery of aminobisphosphonate (alendronate) could be effective in preventing the alveolar bone resorption associated with mucoperiosteal flaps. METHODS: Following mucoperiosteal flap elevation in the molar region of the rat mandible, a surgical pellet soaked with aminobisphosphonate was locally applied on the exposed bone surface and covered by flap. The determined parameters with a semi-quantitative subjective method for the histopathological evaluation were as follows: existing inflammatory cell infiltration of the related periodontal tissue; fibrotic component content and bundles of collagen fibers; the number and morphology of osteoclasts of the alveolar bone and interdental septum; existing resorption lacunae (osteoclast surfaces); and existing osteoblastic activity (forming surfaces). RESULTS: The results showed that while there were no detectable statistically significant differences between the saline and alendronate-treated groups on the existing inflammatory cell infiltration (ICI), number of osteoclasts, and osteoblastic activity, the results for the fibrotic and collagen component, osteoclast morphologies, and existing resorption lacunae were statistically significant. CONCLUSIONS: These results suggest that local application of the aminobisphosphonate alendronate can be used as an adjunct in therapy for reducing bone resorption following surgery. It can also be suggested for consideration that, even for the surgical approaches in dentistry where bone graft materials and/or dental implants are needed, using bisphosphonate may achieve a new dimension in periodontal therapy in the near future.