不同加载时机对微种植体稳定性影响的生物学研究

目的:研究不同加载时间对种植体骨结合状态的影响.方法:采用国产纯钛微螺钉种植体36 枚,家兔18 只(2 枚/只).采用不脱钙硬组织切片技术制作含有种植体的组织学切片,甲苯胺兰染色,在光镜下观察不同加载时机的种植体与周围骨组织结合状况,同时采用电子显微镜观察骨结合界面的超微结构. 结果:组织学切片观察,不加载组种植体周围可见新生的环行骨小梁结构分布均匀,但厚度较2 周加载组小;即刻加载组种植体周围新生骨小梁结构不规则且分布不均,环形层状骨较其他2 组薄;2 周后加载组种植体周围层状骨环行排列,该组新生的环行排列的层状骨的厚度较宽,骨小梁比较粗壮,界限清晰.结论:2 周后加载微种植体稳定性较好,即刻加载稳定性较差,不加力组稳定性介于2 组之间.     

3种特殊染色法显示种植体骨磨片组织学效果比较

目的研究3种特殊染色法显示不脱钙种植体骨磨片的组织学差异,为种植体骨界面研究选择合适的染色方法提供依据。方法将植入Beagle犬胫骨8周的种植体骨标本制作成不脱钙种植体骨磨片,分别采用亚甲基蓝-酸性品红染色法、Goldner’s三色染色法和甲苯胺蓝染色法3种方法进行染色,光学显微镜下观察磨片中种植体骨界面及骨组织,比较3种染色法的染色效果和特点。结果亚甲基蓝-酸性品红染色后种植体骨结合界面清晰,新生骨与原矿化骨分界较模糊,但成骨细胞及细胞核、类骨质显示清晰;Goldner’s三色染色后骨矿化不同阶段显示清晰,但骨细胞因着色浅,显示不清晰,且与类骨质分界不清;甲苯胺蓝染色显示新生骨与原板层骨分界清晰,种植体骨结合界面模糊,骨细胞显示不清晰。结论 Goldner’s三色法和甲苯胺蓝染色法更适用于显示新生骨形成情况,前者显示骨矿化不同阶段效果更好;Goldner’s三色法和亚甲基蓝-酸性品红染色法显示种植体骨结合界面更清晰;种植体骨磨片的细胞学方面研究染色宜采用亚甲基蓝-酸性品红染色法。     

放疗后颌骨骨内种植的Beagle犬动物模型的建立

目的 评估放疗对颌骨骨内种植的影响,以及不同治疗方法对放疗后颌骨骨内种植体周围组织成骨性能、成骨特点、种植体骨结合情况的影响,建立一种符合放疗后颌骨骨内种植特点的动物模型.方法 以Beagle犬为实验动物,拔除其双侧下颌前磨牙和第一磨牙,1个月后,每只犬右侧下颌骨给予50 Gy剂量放射治疗.左侧为对照.放疗后9个月两侧植入埋入式螺纹种植体各4枚,于种植体植入后8周和12周处死动物,取材制作种植体-骨磨片.结果 4只实验犬均无死亡,饮食、活动正常,种植体无松动.组织病理学观察见:8周时,放疗组种植体周围有少量骨组织形成,部分有纤维组织长入,对照组骨组织形成量较放疗组多,与种植体形成了部分骨结合;12周时,两组种植体周围骨组织较8周时明显增加,都与种植体发生了骨结合,对照组的骨组织量及种植体-骨结合程度都优于放疗组.结论 本研究采用的建模方法,较符合放疗后颌骨骨内种植临床实际情况,为今后放疗后骨内种植体周围骨组织再生的研究奠定了动物实验基础.     

基于种植导板的双根种植体植入方法探讨

目的:评价基于种植导板的新型双根种植体植入方法的可行性.方法:对兔胫骨进行CT扫描,制作种植导板.选择12只新西兰大白兔,在种植导板的辅助下于一侧胫骨植入双根种植体,另一侧胫骨植入单根种植体作为对照组.分别于术后8、12周处死动物,直接观察种植体松动度,标本行X线片检查,通过Image Pro-Plus6.0软件测量种植体周围骨质灰度值;制备含种植体的硬组织切片,通过Image Pro-Plus6.0软件测量种植体-骨界面的骨结合率.采用SPSS20.0软件对数据进行t检验.结果:双根种植体植入过程顺利,种植体无明显松动,各时间点实验组和对照组种植体周围骨质灰度值和骨结合率数据差异无显著差异(P＞0.05).结论:基于种植导板的双根种植体植入方法操作可行,植入后双根种植体骨结合良好.     

不同管径TiO2纳米管对小型猪体内种植体的基因表达及骨整合的影响

目的探讨表面具有TiO2纳米管结构的纯钛种植体周围的基因表达以及不同管径的纳米管对种植体-骨界面成骨的影响。方法在小型猪体内植入表面具有TiO2纳米管结构的纯钛种植体,术后3周、5周和8周取出种植体骨块,制作不脱钙磨片,利用光学显微镜,观察术后3周、5周和8周种植体周围骨的组织学表现;并采用定量PCR法检测种植体周围alkaline phosphatase（ALP）、osterix（OSX）、collagen-I（COL-I）的表达。结果与机械切削的纯钛种植体相比,表面具有TiO2纳米管结构的纯钛种植体在骨-种植体接触面积和基因表达方面都有显著的增加,尤其是表面具有70nm纳米管的种植体。结论 TiO2纳米管通过调节种植体-骨界面的成骨活动获得良好的分子应答和骨整合,纳米管的管径可以被精确调控以获得更好的骨生成。     

钛种植体-骨间隙愈合界面成骨方式的激光共聚焦显微镜观察

目的：观察钛种植体一骨界面的新生骨形成情况,探讨在间隙愈合模型中种植体和骨表面是否存在双向成骨现象。方法：将4枚带有环形凹槽的纯钛种植体经喷砂、酸蚀处理后,植入兔股骨远端髁突内。术后第5d和第19d分别肌肉注射钙黄绿素和茜素红。采用激光共聚焦显微镜观察带种植体的硬组织切片。结果：激光共聚焦显微镜显示,种植体的间隙区域均有新生骨组织生成。在间隙区域,骨创面和相应的种植体表面分别存在绿色荧光带（钙黄绿素）,二者问不连续,而在19d时注射的茜素红所标记的红色荧光将二者连接融合,并可见大量红色荧光分布于绿色荧光周围。结论：种植体一骨界面存在远端成骨和接触成骨2种成骨方式,二者相向成骨。     

骨涎蛋白在不同类型种植体骨界面改建中的变化

目的:比较埋植型与非埋植型种植体在义齿修复受载后,种植体-骨界面中骨涎蛋白表达的变化。方法:选用纯系Beagle犬8只,在其下颌左右两侧分别植入埋植型与非埋植型种植体各3枚,每侧第一枚不作义齿修复,用于对照,其余各枚均采用固定金属全冠行种植义齿修复,分别于修复后2、4、8、12周各处死2只动物,取下颌骨相应骨段,于每个种植体周围10 mm处制作颊舌向纵行石蜡切片(片厚4μm),采用免疫组化染色方法检测种植体-骨界面骨涎蛋白表达情况。结果:两对照组(未修复组)种植体-骨界面组织中骨涎蛋白均呈弱阳性表达,且各时间点表达均无明显差异(P>0.05)。而两实验组(修复受载后)种植体-骨界面组织中骨涎蛋白表达的阳性强度均随观察时间延长而增加,8周时达高峰,12周时出现回落;同一时间点内埋植型与非埋植型种植体相比,无论是对照组还是实验组,各时间点内的骨涎蛋白表达程度均无显著性差异(P>0.05)。结论:埋植型和非埋植型种植体在义齿修复受载后,所承受的机械负荷均能刺激种植体-骨界面骨涎蛋白表达发生规律性变化,促进其界面的改建;且埋植型和非埋植型种植义齿受载后其界面的改建之间无显著性差异(P>0.05)。     

关于种植体受持续水平力作用发生移动的实验研究

目的:通过对已完成骨结合的种植体施加水平方向的力,观察种植体在水平力作用下发生移动的情况,并对这种情况下种植体的骨结合情况进行组织病理学观察.材料和方法:6只健康成年杂种犬,恒牙列完全萌出,随机分为A、B两组,每组三只.拔除两组验动物的第一,二前磨牙.拔牙创愈合三个月后,单侧下颌分别植入两枚羟基磷灰石涂层柱状种植体种植体愈合三个月后,在种植体上安装修复基台,并安装加力装置,A,B组分别施加大小为1000g和1500g的持续水平力,第3,6,12周时,测量种植体基台之间的距离.加力12周后处死动物,取标本,固定,包埋制作硬组织磨片,观察种植体-骨界面的骨结合情况.实验结果:A,B组种植体受1000g和1500g的水平力后距离发生了明显变化.X线检查种植体周围没有明显的骨吸收.组织病理学研究显示,加力后的种植体与周围骨组织骨结合情况良好.结论:已经完成骨结合的种植体能够在持续水平力的作用下能够发生倾斜移动,并且能够保持与周围骨组织的骨结合.     

种植体周围炎大鼠模型研究

目的:改良大鼠种植体周围炎模型,简化造模步骤,缩短造模时间.方法:拔除16只大鼠上颌第一磨牙,拔牙窝愈合1个月后植入钛种植体.种植体骨结合4周后用丝线结扎诱导炎症并糖水喂养.结扎后2周观察炎症诱导情况.处死大鼠,取上颌骨拍摄X线片用于影像学分析.制作骨组织切片和提取种植体周围牙龈组织进行免疫组化分析.结果:结扎2周后种...     

TM种植体-骨结合界面的显微CT观察

目的 研究TM种植体-骨结合界面及其上 1/3倒楔形间隙的成骨情况.方法 用医用钝钛钛棒加工成两组种植体,实验组为锥度5.44°、表面进行喷砂酸蚀处理的TM种植体,锥度从种植体上1/3处开始变化;对照组为仿straumann的表面喷砂酸蚀(sandblast large grit and acid-etching,SLA)圆柱状螺纹种植体.建立Beagle犬下颌骨种植模型,3只犬每只植入实验组TM种植体和对照组仿straumann -SLA圆柱状螺纹种植体各4枚,3只实验犬分别于4周、8周和12周处死,截取下颌骨行显微CT三维重建,观察种植体-骨结合界面及上1/3间隙的成骨情况.结果 8周时实验组TM种植体上1/3倒楔形间隙开始有骨修复,12周时对照组仿straumann-SLA种植体颈部骨质有吸收迹象,实验组TM种植体颈部骨质仍得到良好保存.结论 TM种植体能形成良好骨结合界面,体部上1/3的锥度设计可保存颈部皮质骨.     

Potential application of high-resolution microfocus X-ray techniques for observation of bone structure and bone-implant interface

PURPOSE: The aim of the present study was to evaluate the potential application of 2 types of microfocus x-ray units to study the bone structure around dental implants and at the bone-implant interface. MATERIALS AND METHODS: IMZ titanium implants were placed in the maxilla and mandible of a beagle dog. After implantation periods of 1, 2, and 3 months, the bone-implant interface was evaluated with microfocus x-ray computed tomography (CT) and microfocus x-ray fluoroscopy. RESULTS: Microfocus x-ray CT images of the bone-implant specimen at 3 months after implant placement revealed a clear distinction between the implant and the bone. The implant surface was partially covered with bone, and direct contact between the implant and bone could be clearly seen. Differences in degrees of calcification were identified by the differences in relative black and white intensity. Microfocus x-ray fluoroscopy also showed clear features of the bone and titanium implant The original drill hole and new bone formation could be recognized. These findings corresponded with traditional histologic observations by light microscopy. DISCUSSION AND CONCLUSION: Microfocus x-ray techniques are non-destructive and require a very short examination time. They are considered useful to observe details of the bone structure and bone-implant interface. Microfocus x-ray fluoroscope and microfocus x-ray CT techniques can provide a clear and distinguishable image of the bone-implant interface because of their high spatial resolution.     

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。     

Temporal sequence of hard and soft tissue healing around titanium dental implants

The objective of the present review was to summarize the evidence available on the temporal sequence of hard and soft tissue healing around titanium dental implants in animal models and in humans. A search was undertaken to find animal and human studies reporting on the temporal dynamics of hard and soft tissue integration of titanium dental implants. Moreover, the influence of implant surface roughness and chemistry on the molecular mechanisms associated with osseointegration was also investigated. The findings indicated that the integration of titanium dental implants into hard and soft tissue represents the result of a complex cascade of biological events initiated by the surgical intervention. Implant placement into alveolar bone induces a cascade of healing events starting with clot formation and continuing with the maturation of bone in contact with the implant surface. From a genetic point of view, osseointegration is associated with a decrease in inflammation and an increase in osteogenesis‐, angiogenesis‐ and neurogenesis‐associated gene expression during the early stages of wound healing. The attachment and maturation of the soft tissue complex (i.e. epithelium and connective tissue) to implants becomes established 6–8 weeks following surgery. Based on the findings of the present review it can be concluded that improved understanding of the mechanisms associated with osseointegration will provide leads and targets for strategies aimed at enhancing the clinical performance of titanium dental implants.     

表面梯度涂层纯钛植入体骨结合和骨诱导能力的动物实验研究

目的：观察纯钛植入体表面用低温烧结技术生成羟基磷灰石/生物玻璃( nHA/BG)梯度涂层植入动物体内的骨结合和骨诱导能力。方法：将nHA/BG按比例混合,应用低温烧结技术在圆柱形纯钛植入体表面形成梯度涂层,模拟体液浸泡后产生活性纳米结构。将梯度涂层实验植入体和纯钛对照植入体分别植入12只新西兰兔股骨髁。术后不同时间行X线摄片,切取标本;硬组织切片,用四环素荧光标记观察植入体周围新生骨形成量;苦味酸-品红染色观察植入体-骨界面骨沉积和结合情况。结果：低温烧结和模拟体液浸泡制备的nHA/BG梯度涂层为纳米化多孔粗糙结构,动物实验示,梯度涂层植入体与周围新生骨明显增多,骨整合良好。结论：梯度涂层和模拟体液浸泡制备的植入体涂层有良好的骨结合和骨诱导能力。     

CDIC和ITI纯钛种植体周围骨组织生物学基础研究

目的：应用MicroCT、光学显微镜评价国产CDIC和ITI纯钛种植系统与周围骨组织整合的差别。方法：拔除狗的第一、第二磨牙,4个月后应用国产CDIC和ITI种植体植入,同体对照,术后4月、12月处死动物,分别取含种植体的组织块,MicroCT成像建立三维模型后,不脱钙切片甲苯胺蓝染色行光学显微镜对比观察。结果：①.两组种植体均被机体耐受,周围的骨组织均未发现炎症细胞和巨大细胞②.MicroCT、光学显微镜观察均显示ITI比CDIC种植体新骨形成早、量多,一年之后两者骨组织形成量没有显著差别。③MicroCT和光学显微镜对种植体周围骨组织微结构的研究结果具有正相关性。结论：使用国产CDIC种植系统与ITI种植系统骨结合基本相同,在临床上能获得较高的成功率。MicroCT分辨率高,能够建立高清晰三维图像,是对种植体周围骨组织研究的一种准确有效的新方法。     

Implant‐tissue interfaces following treatment of peri‐implantitis using guided tissue regeneration. A light and electron microscopic study.

This study details the structural and ultrastructural features of the interfaces between titanium implants and their surrounding tissues. The material stemmed from an experiment in dogs in which guided tissue regeneration with Gore‐Text membranes was used to treat peri‐implant, ligature‐induced tissue breakdown around submerged and nonsubmerged com-mercially pure titanium implants. Specimens from the nonsubmerged group were evaluated under light microscopy and scanning and transmission electron microscopy. A healthy gingiva and a gingival sulcus were formed around the implant necks. A regenerated junctional epithelium provided the epithelial union between implant and gingiva. The supracrestal connective tissue was characterized by a 3‐dimensional network of collagen fibers, fibroblasts and blood vessels. Near the implant surface the collagen fibers ran parallel to the titanium surface or were orientated perpendicular to the implant. The connective tissue-implant interface was characterized by a fine fibrillar material interposed between the implant surface and the connective tissue. An unidentified material was also observed between the endings of functionally orientated collagen fibrils and the metallic surface. The apical portions of the implants were anchored in compact bone. At the bone‐implant interface, either mineralized bone matrix was intimately adapted to the titanium surface without any intervening space or a 0.5 μm wide unmineralized layer was interposed. These findings indicate that a perimucosal seal was formed around the implants consisting of a junctional epithelium‐implant union coronally and supported by the connective tissue-implant junction apically. The implants were integrated in connective tissue, but only tightly adapted to bone.     

纳米羟基磷灰石/聚醚醚酮复合种植体受力的三维有限元分析

目的:评价纳米羟基磷灰石/聚醚醚酮(Nano-hydroxyapatite/Polyetheretherketone ,n-HA/PEEK)仿生种植材料受力时种植体及其周围骨组织的应力特征,为该种植材料的临床运用提供生物力学依据。方法:根据CT扫描数据及种植体产品数据建立包括牙槽骨、种植体的三维有限元模型,比较在150N垂直加载条件下n-HA/PEEK和钛种植体周围骨皮质及骨松质的应力分布。结果:两种材料应力分布规律:紧邻种植体颈部的骨皮质应力最大远离处逐渐减小,皮质骨内两种材料的表面最大应力有显著性差异(P<0.05)。负重时钛金属种植体其表面应力波动变化范围增大,容易形成应力集中。同骨组织具有相似弹性模量的n-HA/PEEK材料表面应力分布更均匀。结论:n-HA/PEEK材料更有利于将种植体所受载荷以应力的形式传递到周围骨组织中去,有利于保持骨结合面的长期稳定。     

In vivo monitoring of the bone healing process around different titanium alloy implant surfaces placed into fresh extraction sockets

Objectives

Increasing surface roughness and coating with tricalcium phosphate of titanium and titanium alloy implants has been proposed to provide better rates of osseointegration. However, how these changes in surface topography and chemistry influence the osseointegration process of immediate implants placed in fresh extraction sockets is unclear. This study investigated the influence of three clinically employed implant surfaces on the early bone healing events in vivo.

Methods

Machined smooth implants were milled from grade 5 Ti6Al4V titanium. Surfaces were moderately roughened by grit blasting, which were then coated with tricalcium phosphate. Implants were placed into freshly extracted incisor sockets of mandibles of normal Wistar rats and left for 1, 3 and 9 weeks. Healing bone tissue around the implants was examined by histochemistry and immunocytochemistry to localise PCNA proliferative cells, and osteoblast differentiation markers osteopontin and osteocalcin. Positive synthesising cells were counted using image analysis.

Results

Histology indicated no differences in the amount or pattern of bone formation within the healing tissue surrounding the different implant surfaces. Bone healing occurred predominantly on exposed bone surfaces (distance osteogenesis) and not on the implant surface (contact osteogenesis). No differences were observed in the number or timing of PCNA, osteopontin and osteocalcin positive cells within the bone healing tissue around each of the implant analysed.

Conclusion

For immediately placed implants, the surface modifications investigated appeared to have little influence on the activity of bone forming cells surrounding the implant, probably due to the high level of distance osteogenesis seen within this scenario.

Clinical significance

For immediate placement of implants into fresh extraction sockets, titanium implants with roughened surfaces and coating with tricalcium phosphate have negligible influence in accelerating the early bone healing events of osseointegration.     

Histodynamics of bone tissue formation around immediately loaded cylindrical implants in the rabbit

OBJECTIVES: The local mechanical environment influences early peri-implant tissue formation. It is still unclear whether immediate loading limits or promotes peri-implant osteogenesis and which mechanical parameters are important herein. The present study evaluated the influence of well-controlled mechanical stimuli on the tissue response around immediately loaded cylindrical turned titanium implants at two different observation periods. MATERIAL AND METHODS: A repeated sampling bone chamber, consisting of dual-structure perforated hollow cylinders with a cylindrical implant, was installed in the tibia of 14 rabbits and used to conduct three displacement-controlled immediate loading experiments: (i) 30 microm - 400 cycles/day - 1 Hz frequency - 2 x/week - 6 weeks; (ii) 30 microm - 400 cycles/day - 1 Hz - 2 x/week - 6 weeks, followed by another 6 weeks with a 50 microm - 800 cycles/day - 1 Hz - 2 x/week loading protocol; and (iii) 0 microm implant displacement for 12 weeks. A linear mixed model and logistic mixed model with alpha=5% were conducted on the data set. RESULTS: The tissue area fraction was significantly the highest after 12 weeks of loading. The bone area fraction was significantly different between all three loading conditions, with the highest values for the 12-week loading experiment. Twelve-week stimulation resulted in a significantly higher mineralized bone fraction than 6 weeks. Loading did have a significantly positive effect on the mineralized bone fraction. The incidence of osteoid-to-implant and bone-to-implant contact increased significantly when loading the implant for 12 weeks. CONCLUSION: Immediate loading had a positive effect on the tissue differentiation and bone formation around cylindrical turned titanium implants. Controlled implant micro-motion up to 50 microm had a positive effect on the bone formation at its interface.