微纳米共存的磷酸化涂层对钛植入体骨结合的影响

在纯钛植入体表面制备出微纳米共存的具备晶体相“磷”的仿生结构,探究其对钛植入体骨结合的影响。     

仿生微/纳米多级界面增强植入体骨整合的体内研究

目的:研究一种仿生微/纳米多级界面以增强植入体骨整合。方法:纯钛样本分别经放电等离子烧结、电化学阳极氧化或二者复合处理后,分别形成微米级骨小梁仿生结构、TiO2纳米管表面改性结构、微米级骨小梁仿生/TiO2纳米管表面改性结构。取40只雌性SD大鼠随机分为4组(A、B、C、D,n=10),在其膝关节内侧建立直径为1.5 mm的骨缺损模型,分别植入未处理钛、微米级骨小梁仿生钛、TiO2纳米管表面改性钛、微米级骨小梁仿生/TiO2纳米管表面改性钛。12周后,对近端胫骨及钛植入体行组织学分析、Micro-CT评价及生物力学测试。结果:D组骨整合率,相对骨体积和骨体积最高,多项骨小梁相关参数较高,表现出更好的骨整合。此外,D组的最大推出力和临界抗剪切强度均高于其他3组(P<0.05)。结论:仿生微/纳米多级界面增强了钛植入体的骨整合,可作为一种性能优良的材料用于临床治疗。     

钛种植体表面矿化胶原涂层的生物学性能研究

目的钛种植体表面应用电化学沉积技术制备的矿化胶原涂层的生物学性能研究。方法本研究应用电化学沉积技术在钛金属表面制备了矿化胶原涂层,应用模拟体液(SBF)浸泡表征其诱导羟基磷灰石骨性结合能力,利用MTS法检测涂层的细胞粘附及增殖性能。结果制备的矿化胶原涂层能在SBF中稳定存在并继续矿化,能促进植入成骨前体细胞在其表面的粘附、增殖和分化。结论钛种植体表面进行矿化胶原涂层修饰可以有效促进其生物活性。     

新型种植体涂层材料rhBMP-2/PDLLA诱导成骨作用的观察

目的：观察rhBMP-2/PDLLA涂层诱导钛种植体周围新骨形成情况。方法：选取8只比格犬,在其双侧胫骨随机植入PDLLA/rhBMP-2、PDLLA、rhBMP-2涂层和空白种植体,术后2、4、8、12周进行生物力学测定和骨形态计量学分析,比较各组新骨形成和骨结合情况。结果：rhBMP-2/PDLLA涂层种植体周围新骨形成早于其他组;4周时rhBMP-2/PDLLA涂层种植体骨结合明显优于PDLLA组、空白组（P〈0.05）,8周和12周时PDLLA/rhBMP-2涂层种植体骨结合优于PDLLA组,并有大于其他两组的趋势。结论：新型涂层材料PDLLA/rhBMP-2具有促进新骨形成和提高骨结合率的双重作用。     

rhBMP-2/Nha/Co复合膜异位成骨的实验研究

目的:观察rhBMP- 2/nHA/Co复合膜异位诱导成骨的能力.方法: 构建nHA/Co 复合膜和rhBMP- 2/nHA/Co复合生物膜,分别植入裸鼠后肢大腿肌囊,于10、20、30 d后观察成骨情况,并作比较.结果: rhBMP/nHA/Co组材料在裸鼠肌囊内出现骨样结构,异位成骨的能力较nHA/Co组强.结论: 动物实验中Co、nHA均为BMP的良好缓释载体,此复合膜能有效的诱导异位成骨.     

种植体与新生骨结合界面电镜观察研究

目的：通过动物实验观察同期种植体与多孔支架植入后种植体与骨组织的结合状况来为临床应用提供依据。方法：将预制成形的PLA/PGA材料,通过上颌窦提升术植入新西兰兔的上颌窦中,同期植入钛种植体,术后12周全部处死通过大体、组织学及电镜观察成骨及种植效果。结果：12周后肉眼可见所有种植体顶端周围多孔支架均形成骨组织且与新骨结合紧密牢固：扫描电镜和透射电镜均证实新生骨组织与种植体结合紧密。结论：种植时在骨质不足的条件下,可以通过同期植入种植体和多孔支架来同时完成新骨形成及其二者的结合,种植体与新生骨结合牢固,方法有效效果可靠。     

褪黑素对纯钛超声微弧氧化膜层体内植入骨结合的影响

目的 :将具有骨诱导活性的褪黑素引入纯钛超声微弧氧化膜层中,通过动物实验观察能否提高早期骨整合能力。方法:纯钛表面制备超声微弧氧化膜层(A组),再以硅烷为偶联剂(B组),进一步组装褪黑素(C组),植入新西兰大白兔的双侧下颌骨中2、4和6周,利用CBCT、扭力实验、甲苯胺蓝染色观察各组的种植体-骨界面早期成骨情况。结果:纯钛超声微弧氧化膜层经硅烷偶联褪黑素制备的复合膜层表面保留微弧氧化的微孔形貌,增加了利于骨生成和生长的硅、碳和氮元素。添加褪黑素膜层骨结合能力最好,植入4周时的骨结合力达到峰值,其余2组植入6周时的骨结合力才达到峰值。添加褪黑素种植体骨界面新骨形成更早、骨量更多。结论:以硅烷为偶联剂在纯钛表面超声微弧氧化膜层表面组装褪黑素,获得的复合膜层种植体,能加速早期的骨组织的形成,具有更好的生物活性。     

纳米钛膜种植体-骨界面的骨整合研究

目的 研究纳米材料在种植体骨整合方面的作用.方法 以磁控溅射法在纯钛种植体表面制备纳米钛膜,观测其形貌,将其植入动物体内,研究其在动物体内的早期骨整合情况.结果 表面形貌分析显示,磁控溅射在片状种植体和柱状种植体上形成的纳米级颗粒尺度相近,片状种植体纳米颗粒分布更均匀.动物试验显示,纳米级颗粒钛膜可增加种植体在种植初期...     

nHA/BG涂层与Bio-Oss骨粉修复种植体骨缺损的实验研究

目的:评价生物玻璃/纳米羟基磷灰石(nHA/BG)涂层与Bio-Oss骨粉在种植体骨缺损中引导骨再生的效果。方法:选取6只Beagle犬,拔除两侧下颌前磨牙。3个月后预备种植窝,同时颊侧制造裂隙状骨缺损(2.25 mm×3 mm×4 mm)。按照分组植入种植体和骨粉,A组为nHA/BG+Bio-Oss,B组为nHA/BG+血凝块愈合,C组为微米级HA+Bio-Oss。术后2周、处死前2周和3 d分别进行四环素、钙黄绿素和茜素红荧光标记。术后8周和16周处死动物,行大体观察和组织学测量。采用SPSS13.0软件包对数据进行统计学分析。结果:3组骨-种植体结合率(BIC)在8周时分别为30%、18%、21%,16周时分别为61%、53%、46%;缺损区新骨面积(RA)在8周时分别为(2.1±0.6)mm3、(1.4±1.0)mm3、(0.6±0.1)mm3,16周时分别为(4.2±0.7)mm3、(2.2±1.2)mm3、(1.2±0.6)mm3。各组8周与16周的BIC和RA相比均有显著差异(P<0.05);8周时,A、C 2组的BIC和RA相比有显著差异(P<0.05),16周时,A、B 2组的RA相比有显著差异(P<0.05)。结论:在种植体周围2.25 mm骨缺损区,nHA/BG涂层能促进种植体-Bio-Oss替代骨-骨的骨结合。     

羟基磷灰石涂层种植体骨愈合的实验研究

目的：通过动物实验，研究涂覆烧结工艺技术研制的新型羟基磷灰石（HA）涂层种植体的骨愈合情况。方法：将12颗钛种植体（6颗有HA涂层，6颗无涂层）植入6只成年杂种犬下颌骨内，分别饲养1、3、6个月，使种植体在无负荷的条件下愈合。标本进行大体观察、光镜组织学观察以及计算机定量组织形态学评价。结果：两种种植体都能产生骨结合。有涂层的种植体新骨的产生和成熟都比无涂层的钛种植体更为迅速。术后1、3、6个月有涂层种植体的骨结合率分别为71．68％、86．81％、90．19％；无涂层种植体的骨结合率为53．26％、66．16％、68．72％，其间有显著性差异（P＜0．01）。结论：涂覆烧结工艺HA涂层骨内种植体能取得良好的骨结合，涂覆烧结工艺HA涂层能够很好地促进种植体的骨结合。     

选择性激光烧结多孔钛种植体及其性能研究

目的 分析选择性激光烧结（SLS）多孔钛种植体的机械性能及生物相容性,探讨其与壳聚糖（CS）/羟磷灰石（HA）复合涂层结合后的促骨结合作用。方法 制备Ti6Al4V试件,部分试件表面进行CS/HA涂层处理;对试件进行扫描电子显微镜观察和机械性能检测;体外培养MC3T3-E1细胞,进行活/死细胞染色、甲基噻唑基四唑（MTT）及碱性磷酸酶（ALP）水平检测;将柱状螺纹种植体植入兔股骨髁部,分析其体内生物学性能。结果 试件准弹性梯度随孔隙率增大而减小,孔隙率为30%时与皮质骨接近,70%时与松质骨接近;试件具有良好的生物相容性。复合CS/HA涂层后可促进MC3T3-E1细胞增殖、分化,有利于骨组织长入孔隙,形成良好的骨结合。结论 多孔钛种植体具有良好的机械性能和生物相容性,与CS/HA涂层结合后具有骨诱导性,利于形成稳定的骨结合。     

Bioactive glass and calcium carbonate granules as filler material around titanium and bioactive glass implants in the medullar space of the rabbit tibia

The effect of bioactive glass (BG) and calcium carbonate (CC) granules on bone formation around titanium and BG implants projecting into the medullary space of rabbit tibia was studied. The bone marrow tissue was removed and the medullary space was filled either with BG or CC (Biocoral®) granules (0 630μ800 –m). Conical titanium and BG implants were inserted into the holes drilled in compact bone using the press fit technique. Histomorphometry was used to measure the bone‐biomaterial area in a 1.O mm wide zone around the head of the implant and the contact between formed bone and implant. Significantly larger bone-biomaterial area was obtained around titanium implants using BG than CC granules while no difference was found in connection of BG implants. Better bone‐implant contact was achieved with BG implants than with titanium implants regardless of the type of granules used. The results indicate that BG may prove to be useful as filler and coating material in connection of implants projecting into bone cavities.     

Long-term bone response to titanium implants coated with thin radiofrequent magnetron-sputtered hydroxyapatite in rabbits

PURPOSE: The present study was designed to investigate the long-term bone response around machined screw-type uncoated and calcium phosphate (CaP) -coated commercially pure titanium implants. MATERIALS AND METHODS: Using a magnetron sputtering technique, implants with a CaP coating similar in composition and CaP ratio to hydroxyapatite were produced. Heat treatment was subsequently used to increase the crystallinity of the coatings. Four types of coatings (0.1 and 2.0 microm amorphous and 0.1 and 2.0 microm crystalline) were manufactured; uncoated implants served as a control. Three hundred twenty implants (64 of each type) were randomly placed in the tibial cortical and trabecular femoral bones of 40 rabbits. The rabbits were sacrificed 9 months after implant placement. RESULTS: Histomorphometric evaluation carried out on ground sections revealed that the crystalline CaP coatings achieved the highest bone-implant contact in both tibiae and femora compared with amorphous CaP-coated and uncoated titanium. DISCUSSION: The present study suggests that submicron crystalline hydroxyapatite coating adds bioactive properties to titanium oral implants. CONCLUSION: An ultra-thin, 0.1-microm crystalline CaP coating can elicit and maintain an improved long-term bone response compared to amorphous coated or uncoated Ti implants, without any adverse tissue reactions.     

Characterization of bone around titanium implants and bioactive glass particles: an experimental study in rats

PURPOSE: Many situations in clinical practice require metallic implants to be combined with bone grafts and/or bone substitutes such as bioactive glass (BG). Upon implantation, silica-based BG particles are transformed into a shell containing calcium and phosphate that loses its inner silicon-rich core. The release of silicon by BG particles and its incorporation by newly formed bone tissue in the peri-implant area had not been studied to date. MATERIALS AND METHODS: Thirty Wistar rats were used throughout. Under anesthesia, a commercially pure titanium (Ti) laminar implant was placed inside the medullary compartment of the tibia (Ti group), while in the contralateral tibia (Ti/BG group) a titanium laminar implant and melt-derived BG 45S5 particles were implanted. The animals were sacrificed 14, 30, and 60 days postimplantation. The tibiae were resected, radiographed, and embedded in methyl methacrylate resin. Sections were stained with toluidine blue and analyzed by light microscopy and energy-dispersive x-ray analysis (EDX). The presence of silicon, calcium, and phosphorus was evaluated in the BG particles and in the peri-implant bone tissue for each of the experimental times. RESULTS: The histomorphometric study revealed an increase in peri-implant bone thickness in the Ti/BG group as compared to the Ti group. EDX of newly formed bone tissue showed a transient appearance of silicon at 14 and 30 days postimplantation and a rise in the calcium:phosphorus ratio in peri-implant bone tissue in the Ti/BG group. DISCUSSION: The present study shows an increase in reactive medullary bone formation when BG particles are implanted around a Ti implant. CONCLUSION: The results described in the present study reveal that the release of Si by BG particles is an important issue that warrants further study.     

In vitro corrosion behavior of bioceramic, metallic, and bioceramic-metallic coated stainless steel dental implants.

OBJECTIVES: The most common metals and alloys used in dentistry may be exposed to a process of corrosion in vivo that make them cytotoxic. The biocompatibility of dental alloys is primarily related to their corrosion behavior. The aim of this work was to evaluate the corrosion behavior and thus the biocompatibility of the uncoated and coated stainless steels and compare the effect of type of coatings on corrosion behavior. METHODS: Three types of coatings, hydroxyapatite (HA), titanium (Ti), and a double-layer HA/Ti on AISI 316L stainless steel were made. HA coating was produced using plasma-spraying technique and Ti coating was made using physical vapor deposition process. In order to perform a novel double-layer composite coating, a top layer of HA was plasma-sprayed over a physical vapor deposited Ti layer on AISI 316L stainless steel. Structural characterization techniques including XRD, SEM and EDX were used to investigate the microstructure, morphology and crystallinity of the coatings. Electrochemical potentiodynamic tests were performed in physiological solutions in order to determine and compare the corrosion behavior of the coated and uncoated specimens as an indication of biocompatibility. RESULTS: Double-layer HA/Ti coating on AISI 316L SS had a positive effect on improvement of corrosion behavior. The decrease in corrosion current densities was significant for these coated specimens and was much lower than the values obtained for uncoated and single HA coated specimens. Ti coating on AISI 316L SS also has a beneficial effect on corrosion behavior. The results were compared with the results of corrosion behavior of HA coated commercially pure titanium (cpTi) and uncoated cpTi. SIGNIFICANCE: These results demonstrated that the double-layer HA/Ti coated 316L SS can be used as an endodontic implant and two goals including improvement of corrosion resistance and bone osteointegration can be obtained simultaneously.     

In vivo evaluation of the trabecular bone behavior to porous electrostatic spray deposition-derived calcium phosphate coatings

OBJECTIVES: Electrostatic spray deposition (ESD) is a new technique to deposit calcium phosphate (CaP) coatings. The aim of the present study was to evaluate the bone behavior of ESD CaP-coated implants with various degrees of crystallinities in the trabecular bone of the femoral condyle of goats. MATERIAL AND METHODS: Using the ESD technique, thin porous CaP coatings were deposited on tapered, conical, screw-shaped titanium implants. Three different heat-treatments were applied, resulting in amorphous CaP (400 degrees C, ESD1), crystalline carbonate apatite (500 degrees C, ESD2), and crystalline carbonated hydroxyapatite (700 degrees C, ESD3). Implants were inserted into the trabecular bone of the femoral condyles of goats for 12 weeks, and titanium (Ti) implants served as controls. RESULTS: The results showed that ESD-derived coatings are osteocompatible. Histomorphometrical analysis showed that the application of a CaP coating resulted in more bone contact along the press-fit area of the implant compared with the Ti implants. Moreover, the percentage bone contact of the ESD3-coated implants was increased, compared with the Ti control group. Regarding the other coatings, no differences were found compared with the control group. CONCLUSION: Crystalline carbonated hydroxyapatite ESD-coated implants positively influenced the biological performance compared with Ti control implants.     

Bone response adjacent to calcium phosphate electrostatic spray deposition coated implants: an experimental study in goats

BACKGROUND: A new technique to deposit calcium phosphate (CaP) coatings onto titanium substrates has been developed recently. This electrostatic spray deposition (ESD) technique seems to be very promising. It appears to have clinical advantages such as an inexpensive and simple set-up, high deposition efficiency and the possibility to synthesize layers with a defined surface morphology. OBJECTIVE: The aim of this study was to examine biological properties and osteoconductivity of ESD CaP coatings when inserted into the femoral condyle of a goat. MATERIAL AND METHODS: Twenty-four implants with two gaps, i.e. 1 or 2 mm, were inserted into the femoral condyles of six goats. The implants were coated on one side with either a commercially available plasma-sprayed hydroxyapatite (HAPS) coating or an ESD carbonate apatite (CAESD) coating. The other side of the implant was always left uncoated (Ti). Twelve weeks after implantation the animals were sacrificed and the characteristics of bone ingrowth and bone contact were evaluated. Results: At 3 months, histological and quantitative histomorphometrical measurements demonstrated more bone ingrowth and bone contact for coated sites as compared with uncoated sites. Statistical testing revealed that for both the 1 and 2 mm gaps HAPS (plasma-sprayed hydroxyapatite) as well as CAESD (ESD carbonate apatite) -coated surfaces always had a significantly higher (P<0.05) amount of bone contact than uncoated Ti surfaces. On HAPS surfaces always significantly more bone was present than on CAESD surfaces. Further statistical testing revealed a significant difference in bone ingrowth between the HAPS as well as CAESD and Ti 1+2 mm gap specimens (P<0.05). Further, HAPS 1 mm gaps showed more bone ingrowth than CAESD 1 mm gaps. No significant difference existed between HAPS and CAESD 2 mm gaps. CONCLUSION: On the basis of our observations, we conclude that the used ESD technique is a promising new method to deposit CaP coatings onto titanium substrates. On the other hand, plasma-spray HA-coated implants have a still more favourable effect on the bone response.     

The effect of three different calcium phosphate implant coatings on bone deposition and coating resorption: a long-term histological study in sheep

The present study investigated the hypothesis that hydroxyapatite (HA), tricalcium phosphate (TCP), and a HA-gel coated on endosseous titanium (Ti) implants by spark discharging (SD) and dip coating would achieve predictable osseointegration without evident bioresorption of the coatings on the long term. A costal sheep model was used for the implantation of the HA/SD, HA/TCP/SD, and HA-gel/SD specimens, which were retrieved 6 and 12 months following implantation. HA and Ti coatings on implants obtained by conventional plasma spraying (HA/PS, Ti/PS) were used as controls. Microscopy showed that osseointegration was achieved from all types of implants. No evidence for bioresorption of the HA/SD, HA/TCP/SD, and HA-gel/SD coatings was present but cohesive failure with disruption of the coating/implant interface was seen. A statistical analysis of the histomorphometrical data showed no time-dependent effect, however. HA/PS coatings achieved significantly higher bone-implant contact (BIC) percentages of the total implant surface (toBIC) than the other types of coatings (P=0.01). If the BIC percentages were traced separately for implant portions placed into cortical and cancellous bone (coBIC and caBIC, respectively), detailed analysis showed that the caBIC values of HA-gel/SD and HA/PS coatings were significantly higher than that of the other types of coatings (P=0.01). CaBIC values were highly correlated with toBIC values (P<0.001). The present study showed that the preparation techniques used produced thin, dense, and unresorbable coatings that achieved osseointegration. Compared with the control coatings, however, only HA-gel/SD coating can be recommended from the investigated preparation techniques for a future clinical use if a better coating cohesion is achieved.