Long-term effects of magnetron-sputtered calcium phosphate coating on osseointegration of dental implants in non-human primates

Objectives: To determine the effect of magnetron-sputtered calcium phosphate coating of implants on the later stages of osseointegration in a non-human primate model.
Material and methods: Eighteen and 20 implants with a 0.1 μm amorphous calcium phosphate coating and a turned surface, respectively, were inserted in the anterior upper and lower jaw of adult non-human primates. Following a 7.5 months healing period, one part of the implants remained in the submerged position. The other part of implants was connected to healing abutments to allow peri-implant inflammation to occur. After another 20 months, histologic and histomorphometric analysis of the peri-implant area was performed.
Results: Submerged implants with a calcium phosphate coating and a turned surface showed no signs of an inflammatory reaction. The histomorphometric parameters 'bone volume per tissue volume' (BV/TV) and 'bone-to-implant contacts' (BIC) were not affected by calcium phosphate coating. Non-submerged implants of both groups showed occasionally signs of inflammation at the implant–abutment junction. Histomorphometric analysis revealed that the distance between the implant–abutment junction and the most coronal level (where bone was attached to the implant) as well as BV/TV and BIC were independent from the surface modification.
Conclusion: Our results show that dental implants with calcium phosphate coating behave similar to turned implants independently whether they are connected to healing abutments or remain submerged. Ultra-thin calcium phosphate coating can combine the positive effects of calcium phosphate during the early stage of osseointegration without causing impairment of the later stages.     

复合玻璃梯度涂层种植体的实验研究

目的:研究亚音速火焰喷涂方法制备的三种表面复合梯度涂层种植体的骨结合界面情况.方法:在钛合金(Ti-6Al-4V)表面形成三组涂层种植体,8Ti2G组:表面喷涂80％钛(Ti)粉+20％玻璃(G)粉(质量比=8∶2);HA组:喷涂80％钛(Ti)粉+20％玻璃(G)粉作为底层,在其上喷涂100％羟基磷灰石(HA)粉;8H2B组:喷涂80％钛(Ti)粉+20％玻璃(G)粉作为底层,在其上喷涂80％羟基磷灰石(HA)粉+20％生物活性玻璃(BG)粉.选择8只3月龄的杂种犬,拔除双侧下颌前磨牙,待拔牙创愈合后,将三组种植体分别植入双侧无牙区的下颌骨内,术后4周和12周分别处死犬4只.采用大体观察、组织学等方法观察种植体与骨的结合情况.结果:X射线显示在所有种植体周围无明显阴影,8Ti2G底釉涂层具有良好的生物相容性,8Ti2G/HA和8Ti2G/8H2B涂层种植体与骨组织均形成骨性结合,同一观察期,界面骨结合率比较有差异.结论:8Ti2G/8H2B种植体达到生物活性梯度变化,孔隙结构梯度变化.该研究为生物复合涂层的应用提供理论依据.     

磷酸钙溶胶涂层对多孔型种植体表面骨内向生长的影响

目的:探讨磷酸钙(CaP)溶胶涂层是否能促使多孔型钛合金(Ti-6Al-4V)种植体表面骨内向生长(即骨组织向孔内生长)。方法:将制备有极薄的CaP溶胶表面涂层的多孔型钛合金种植体作为实验组,未经CaP涂层的种植体作为对照组,分别植入16只实验兔的胫骨中。种植区愈合2周后,取含种植体的骨组织标本,利用反向扫描电镜摄像技术进行形态学观察。应用SAS6.0软件进行方差分析,检测不同实验组间以及CaP涂层与非涂层种植体间是否存在统计学差异。结果:在多孔型钛合金种植体表面,CaP涂层实验组比对照组有更广泛的骨组织向孔内生长。CaP涂层实验组反映骨内向生长的加权平均“颈区”数为2.01,对照组为1.49,两组间的差异存在显著性意义(P<0.01)。结论:早期愈合仅2周,多孔型种植体表面CaP溶胶涂层能有效地促使骨组织向孔内生长,形成骨与种植体界面广泛的骨结合。     

A systematic review on the long-term success of calcium phosphate plasma-spray-coated dental implants

The objectives of the current review were (1) to systematically appraise, and (2) to evaluate long-term success data of calcium phosphate (CaP) plasma-spray-coated dental implants in clinical trials with at least 5 years of follow-up. To describe the long-term efficacy of functional implants, the outcome variables were (a) percentage annual complication rate (ACR) and (b) cumulative success rate (CSR), as presented in the selected articles. The electronic search yielded 645 titles. On the basis of the inclusion criteria, 8 studies were finally included. The percentage of implants in function after the first year was estimated to be 98.4 % in the maxilla and 99.2 % in the mandible. The estimates of the weighted mean ACR-percentage increased over the years up to 2.6 (SE 0.7) during the fifth year of function for the maxilla and to 9.4 (SE 8.4) for the mandible in the tenth year of function. After 10 years, the mean percentage of successful implants was estimated to be 71.1 % in the maxilla and 72.2 % in the mandible. The estimates seem to confirm the proposed, long-term progressive bone loss pattern of CaP-ceramic-coated dental implants. Within the limits of this meta-analytic approach to the literature, we conclude that: (1) published long-term success data for calcium phosphate plasma-spray-coated dental implants are limited, (2) comparison of the data is difficult due to differences in success criteria among the studies, and (3) long-term CSRs demonstrate very weak evidence for progressive complications around calcium phosphate plasma-spray-coated dental implants.     

Biomimetic treatment on dental implants for short-term bone regeneration

Objectives

The main purpose of this work was to assess the short-term bone regenerative potential of new osteoconductive implants. The novelty of the study lies in the analysis of the effectiveness of a novel two-step treatment which combines shot-blasting with a thermo-chemical treatment, at very short times after implant placement in a minipig model.

Materials and methods

Three hundred twenty implants with four different surface treatments, namely bioactivated surfaces, micro-rough grit-blasted, micro-rough acid-etched and smooth as-machined titanium implants were placed into the bone of 20 minipigs. The percent of bone-to-implant contact was determined 3 days, 1, 2, 3 and 10 weeks after implant placement by histomorphometric analysis. Surface composition, topography and wettability of the implant specimens were analysed.

Results

The combination of shot-blasting and thermo-chemical treatment accelerated bone regeneration at early stages in comparison with all other treatments between day 3 and week 3 (p?<?0.05). The value of osseointegration attained at week 2 was maintained until the end of the experiment without any significant changes (percent direct contact?≈?85 %). This was mostly attributed to the ability of these implants to form in vivo a layer of apatitic mineral that coated the implant and could rapidly stimulate bone nucleation and growth from the implant surface.

Conclusions

The surface quality resulting from this treatment on cpTi provided dental implants with a unique ability of rapid bone regeneration and osseointegration.

Clinical relevance

This treatment represents a step forward in the direction of reducing the time prior to implant loading.     

Effects of a calcium phosphate coating on the osseointegration of endosseous implants in a rabbit model

Objectives: The aim of the present study was to evaluate a Ca–P coated implant surface in a rabbit model. The Ca–P surface (test) was compared to the titanium porous oxide surface (control) in terms of bone‐to‐implant contact (BIC) and removal torque value. Materials and methods: Two hundred and sixteen dental implants were inserted in the tibia and in the femur of 36 rabbits. One hundred and eight were represented by Ca–P oxidized surface implant and other 108 were titanium porous oxide surface modified implants. Each rabbit received six implants. Animals were sacrificed after 2, 4 and 9 weeks of healing. Each group included 12 rabbits. The femoral implant and the proximal implant of the tibia of each animal were subjected to the histologic analysis and the distal implants of the tibia underwent removal torque test (RTQ). Results: Histological analysis in terms of BIC and RTQ did not revealed any significant difference between the Ca–P oxidized surface and the oxidized surface at 2 and 4 weeks. At 9 weeks, the oxidized surface demonstrated better results in terms of RTQ in the tibia. Conclusion: In conclusion, findings from the present study suggested that the Ca–P coating had no beneficial effect in improving bonding strength at the bone–implant interface either at 2, 4 and 9 weeks. To cite this article:
Fontana F, Rocchietta I, Addis A, Schupbach P, Zanotti G, Simion M. Effects of a calcium phosphate coating on the osseointegration of endosseous implants in a rabbit model
Clin. Oral Impl. Res. 22 , 2011; 760–766
doi: 10.1111/j.1600‐0501.2010.02056.x     

Formation of crystalline calcium phosphate coating on the titanium dioxide layer of dental implants' surface

Production of octacalcium phosphate crystals on the surface of titanium dioxide particles was achieved at high concentration of titania particles. Optimising the speed of addition of the reagents in the process of crystal growth in heterogeneous nucleation reaction led to reproducible OCP crystal structure on the particle surface. The crystal structure of OCP was investigated by SEM, XRD and FTIR methods. The same crystallization process on the surface of metallic titanium plates did not result in formation of OCP crystals. The evaporated titanium layers on a glass surface and titanium plates without excimer laser treatment did not bond calcium phosphate at any rate. SEM investigations imply that the surface layer of titanium plates changes radically due to laser beam treatment, likely because of oxidation of titanium in the process of evaporation followed by deposition back onto the surface. The calcium phosphate formation on these oxidised titanium plates could be observed by SEM. It can be concluded, that for OCP-formation on titanium metal surface it is necessary to form a thick oxide layer, as the native oxide layer in the case of non-treated titanium substrates did not bound the calcium phosphate, while formation of calcium phosphate could be reached on the laser-treated surface.     

复合BMP-2/bFGF的多孔磷酸钙修复种植体周围骨缺损的实验研究

目的:研究多孔磷酸钙人工骨(porous calcium phosphate cement,CPC)与重组人骨形成蛋-2(recombinant humanbone morphogenetic protein 2,rhBMP-2)/碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)复合构建的组织工程骨修复种植体周围骨缺损的成骨效果.方法:拔除4只beagle犬的双侧下颌第2、3、4前磨牙和第1磨牙后3个月,培养犬的骨髓基质细胞(bone marrow stromai cells,BMSCs),以6×105/ml浓度接种于多孔CPC上;于犬双侧下颌骨拔牙处建立量化的6个骨缺损区(直径7.0mm、深4.0mm),同期植入3.75mm×10mm的Br?nemark种植体,种植体周围骨缺损区分别植入①CPC+BMSCs;②cPc+BMSCs+BMP-2;③CPC+BMSCs+bFGF;④CPC+BMSCs+BMP-2+bFGF;⑤CPC;以空缺作为对照组,在处死前作四环素和钙绿素双次标记,于术后12周取材,进行大体观察和硬组织切片观察.结果:BMSCs/CPC/BMP-2/bFGF复合物组成骨最活跃,缺损区种植体已与骨形成良好的骨结合,骨矿化沉积率高于其它组.结论:BMP-2/bFGF修复骨缺损的成骨作用明显优于单一因子;多孔CPC具有良好的骨引导作用,是一种较理想的临床骨修复材料.     

Effect of calcium phosphate surface coating on bone ingrowth onto porous-surfaced titanium alloy implants in rabbit tibiae.

PURPOSE: The purpose of the present study was to determine whether calcium phosphate coating has a significant impact on bone ingrowth into a porous titanium implant. MATERIALS AND METHODS: Porous-surfaced titanium alloy Ti-6Al-4V implants were prepared with or without the addition of a thin surface layer of calcium phosphate applied by sol-gel coating. Implants were placed into the tibiae of 16 rabbits. Implanted sites were allowed to heal for 2 weeks, after which specimens were retrieved for morphometric assessment using backscatter scanning electron microscopy. RESULTS: The data collected show that there is more extensive ingrowth into the porous regions of the calcium phosphate-coated implants than into the control implants. The weighted average ingrowth for the calcium phosphate-coated implants was 2.01, whereas that for the noncoated implants was 1.49; the difference is statistically significant (P <.01). CONCLUSIONS: The addition of a thin layer of calcium phosphate to these implants appears to promote a more extensive implant-to-bone interface by allowing the neck regions to become intimately ingrown with bone even after only 2 weeks of initial healing.     

Effect of calcium phosphate ceramic implants on tooth eruption

This study evaluated the effects of calcium phosphate ceramics, hydroxylapatite, and tricalcium phosphate implants on tooth eruption and development. Forty kittens, three to four months of age, had their primary right second and third mandibular premolars extracted and the sockets packed with either hydroxylapatite, tricalcium phosphate, autogenous cancellous marrow, or nothing. The results of this study indicated that the use of a nonresorbable hydroxylapatite for grafting resulted in impediment of tooth eruption and distortion of crown development. This was in contrast to the tricalcium phosphate, which had minimal effect on tooth eruption and development.     

The effect of calcium phosphate implant coating on osteoconduction

OBJECTIVE: The purpose of this study was to determine whether a calcium phosphate (CaP) coating would have a significant impact on osteoconduction.Study Design: In this investigation, porous-surfaced titanium alloy (Ti-6Al-4V) implants were prepared with or without the addition of a thin surface layer of CaP applied by means of sol-gel coating and implanted into the tibiae of 16 rabbits. Implant sites were allowed to heal for 2 weeks, after which specimens were retrieved for morphometric assessment by using backscatter scanning electron microscopy and the Bioquant Image Analyzer. RESULTS: The absolute contact length was significantly (P <.01) higher for CaP-coated implants (1.18 mm) than for the noncoated implants (0.74 mm), as were the contact length fraction (40.4% vs 27.0%; P <.01) and the straight-line bone growth (1.19 mm vs 1.04 mm; P <.01). CONCLUSION: On the basis of the findings in this study, the addition of a thin layer of CaP to the implant promotes accelerated bone healing around porous-surfaced implants-even after only 2 weeks of initial healing.     

Biomimetic calcium phosphate coating on medical grade stainless steel improves surface properties and serves as a drug carrier for orthodontic applications

ObjectiveRecently, stainless steel (SSL) miniscrew implants have been used in orthodontic clinics as temporary anchorage devices. Although they have excellent physical properties, their biocompatibility is relatively poor. Previously, our group developed a two-phase biomimetic calcium phosphate (BioCaP) coating that can significantly improve the biocompatibility of medical devices. This study aimed to improve the biocompatibility of SSL by coating SSL surface with the BioCaP coating.MethodsTitanium (Ti) discs and SSL discs (diameter: 5 mm, thickness: 1 mm) were used in this study. To form an amorphous layer, the Ti discs were immersed in a biomimetic modified Tyrode solution (BMT) for 24 h. The SSL discs were immersed in the same solution for 0 h, 12 h, 24 h, 36 h and 48 h. To form a crystalline layer, the discs were then immersed in a supersaturated calcium phosphate solution (CPS) for 48 h. The surface properties of the BioCaP coatings were analysed. In addition, bovine serum albumin (BSA) was incorporated into the crystalline layer during biomimetic mineralisation as a model protein.ResultsThe morphology, chemical composition and drug loading capacity of the BioCaP coating on smooth SSL were confirmed. This coating improved roughness and wettability of SSL surface. In vitro, with the extension of BMT coating period, the cell seeding efficiency, cell spreading area and cell proliferation on the BioCaP coating were increased.SignificanceThese in vitro results show that the BioCaP coating can improve surface properties of smooth medical grade SSL and serve as a carrier system for bioactive agents.     

钛合金植入物表面钙磷涂层处理的研究进展

钛合金材料表面的生物活化处理是近年生物医用材料研究的热点.本文综述了钛合金的表面改性、羟基磷灰石涂层的种类及工艺.纳米涂层技术将是今后钛及钛合金表面活化处理技术的发展方向.     

酪蛋白磷酸肽钙磷复合体在牙菌斑中的作用

酪蛋白磷酸肽钙磷复合体是由一种含成簇磷酸丝氨酸的生物活性肽———酪蛋白磷酸肽与无定形磷酸钙经生物结合而形成,具有重要的生物活性,是一种新型的生物防龋制剂。本文就其结构特征、在牙菌斑中对主要致龋菌的影响、抑制脱矿及促进早期龋再矿化作用,以及研究展望等方面作一综述。