改良喷砂表面处理提高钛牙种植体骨结合的界面生物力学研究

目的：研究改良喷砂表面处理对钛牙种植体骨界面剪切强度的影响。从界面生物力学角度证实改良喷砂表面处理在钛牙种植体中应用的可行性和应用价值。方法：将光滑表面钛种植体与改良喷砂表面种植体随机植入狗股骨内侧髁,分别于植入后2、4、12周取材,Instron电子拉伸试验机检测种植体骨界面的剪切强度。扫描电镜与X－射线能谱分析仪观察植入12周拔出的种植体表面,并进行元素分析。结果：改良喷砂表面组骨界面剪切强度明显高于光滑表面组,约高出4倍,且植入2周即已获得超出光滑表面组12周所能达到的最大强度。植入12周后拔出的改良喷砂表面种植体表面经扫描电镜观察与X－射线谱分析,提示种植体表面大部分被覆骨组织,粗糙表面的二级窝洞内充满骨样组织。结论：改良喷砂表面处理所获得的粗糙表面可以大大地提高牙种植体骨界面的结合强度。此类粗糙表面所特有的二级窝洞在这里起着重要作用。     

改良喷砂钛种植体表面加快骨愈合的细胞学研究

目的　体外研究改良喷砂表面对成骨细胞功能、分化的影响 ,从细胞水平揭示该表面促进骨愈合的作用机制。方法　成骨细胞为原代分离、培养的第 5代人胚成骨细胞 ,选择细胞层碱性磷酸酶 (alkalinephosphatase,ALP)活性、蛋白质含量以及培养液中骨钙素含量作为评价成骨细胞功能、分化的 3项指标。采用酶动力法检测ALP活性、采用考马斯亮蓝法测定蛋白质含量、采用放免测定技术检测骨钙素含量 ,所得各值进行标准化处理。实验分 3组 :改良喷砂表面组、光滑表面组和细胞培养板空白对照组 ,细胞培养取 4d和 1 3d两个时间点。结果　细胞培养 4d ,改良喷砂表面组细胞层ALP活性 [(1 7 390± 1 59)nmolPNP·min- 1 ·1 0 - 6 个细胞 ]、蛋白质含量 [(1 52 7± 1 6 3) μg/1 0 6个细胞 ]以及培养液中骨钙素含量 [(43 0± 6 1 )ng/1 0 6 个细胞 ]均明显高于光滑表面组 [分别为(1 0 978± 1 879)nmolPNP·min- 1 ·1 0 - 6 个细胞、(58 0± 5 9) μg/1 0 6 个细胞及 (2 4 9± 6 0 )ng/1 0 6 个细胞 ]。培养至 1 3d ,各项指标两组间差异消失。结论　从细胞学角度证明改良喷砂表面具有加快种植体骨愈合的作用 ,该作用是通过促进成骨细胞分化和功能表达实现的     

改良喷砂表面处理对钛牙种植体骨结合的组织学作用

研究改良喷砂表面处理对钛牙种植体骨结合的影响。方法柱状纯钛种色植分两组（光滑表面和改良喷砂表面组）进行表面处理,植于狗后肢股骨内侧髁,分别于2、4、12周取材、固定、脱钙后常规HE染色,光镜观察。结果：改良喷砂表面组与光滑表面组的骨愈合过程,均为膜内成骨,并形成完全的骨结合。二者的差别主要表现在愈合的早期（割周）,改良喷砂表面组界面成骨较快,愈合中晚期差别不明显。结论：改良喷砂表面处理可以加快钛牙种植体的骨结合速度。     

锶磷灰石涂层钛种植体骨结合的动物实验

目的 观察微弧氧化锶磷灰石(strontium-substituted hydroxyapatite,Sr-HA)涂层钛种植体的成骨活性,探讨锶元素掺入羟基磷灰石(hydroxyapatite,HA)涂层后对骨结合的影响.方法 分别对实验组(Sr-HA涂层种植体)和对照组(HA涂层种植体)的表面形貌进行扫描电镜观察,并采用X线衍射仪分析膜层相组成.将两组种植体各12枚植入新西兰兔双侧股骨髁下外侧、胫骨结节处,术后对实验动物进行多荧光序列标记,饲养4周和12周取材,采用组织学观察、种植-骨界面线扫描分析评价涂层的骨结合能力.结果 种植体微弧氧化膜层均呈现多级孔洞状结构;X射线衍射分析显示,锶元素的掺入引起HA的衍射峰向小角度方向偏移,晶格间距增大,稳定性下降;多荧光序列标记显示,Sr-HA涂层早期即表现出成骨活性,实验组骨矿化沉积率[(4.75±0.46)μm/d]显著高于对照组[(3.21±0.44)μm/d];组织染色及能谱分析显示,骨种植界面上有生物类骨磷灰石层形成,12周时该磷灰石层转化为成熟的骨组织并与涂层形成紧密的骨结合.结论 锶元素的掺入可提高Sr-HA涂层的生物学活性,加速其表面生物类骨磷灰石层的形成,增强膜层的成骨能力,促进膜层与骨组织的结合.     

Improvement of osseointegration of titanium dental implant surfaces modified with CO ions: a comparative histomorphometric study in beagle dogs

The aim of this study was to compare carbon-oxygen (CO) ion implantation as a surface treatment with diamond-like carbon and commercially treated implants, including double acid-etched (Osseotite), oxidized (TiUnite) and sandblasted and acid-etched (SLA), using machine-turned titanium implants as control. A total of 72 dental implants divided into 6 groups were placed in the mandibles of 12 beagle dogs. Evaluation was performed by conventional light transmission microscopy and environmental scanning electron microscopy (ESEM). The histological results obtained via ESEM demonstrated bone-implant contact percentage (%BIC) for implants treated with CO ion implantation of 61% and 62% at 3 and 6 months, respectively. At the same time points, the values were 48% and 45% for double acid-etched, 46% and 52% for sandblasted and acid-etched, 55% and 46% for oxidized, and 33% and 49% for machine-turned titanium control implants. Values of %BIC were statistically significantly higher in implants treated with CO ion implantation compared to the commercially treated implant group (p=0.002 and p=0.025) and the control implants (p=0.001 and p=0.032) at 3 and 6 months, respectively. No significant differences were observed between the three groups of commercially treated implants. The larger %BIC of the ion-implanted group was observable at an early stage.     

Effects of a modified sandblasting surface treatment on topographic and chemical properties of titanium surface

A modified sandblasting surface treatment (a noncoating, roughening surface modification of dental implants) has been developed that will overcome the defects of conventional coating techniques. To verify the feasibility and reliability of this method at the chemical and topographic levels, scanning electron microscopy, x-ray diffraction, and a titanium ion releasing test were used; the topography of titanium surface, the embedding of sandblasting particles, nonpollution of heteroelements, and anticorrosiveness of titanium were criteria. Results showed that the rough surface created by sandblast was rather irregular, full of sharp tips and many embedded sandblast particles, and its corrosive rate was increased. These characteristics were modified by oxalic acid attack; the contour of the rough surface became more regular and round, the embedded particles and the heteroelement pollution were thoroughly removed, and the Ti corrosive rate decreased dramatically. Oxalic acid attack modification also created numerous secondary micropores (2.0-micron diameter) on the basis of sandblasted surface macrotexture. This modified sandblasting surface treatment is feasible and reliable to apply to dental implants and does not decrease the biocompatibility of titanium.     

Effect of recombinant human bone morphogenetic protein-2 on the osseointegration of dental implants: a biomechanics study

Background Bone augmentation procedures in combination with dental implants enhance osseointegration in areas that demonstrate localized bone deficit. Clinical confirmation of a biomechanically stable interface is essential for functional implant loading.Purpose The aim of this study was to evaluate biomechanically the effect of recombinant human bone morphogenetic protein (rhBMP)-2 on implant osseointegration and correlate it with periotest and radiographic measurements.Materials and methods Hollow cylinder implants were filled with absorbable collagen sponge soaked with rhBMP-2 or left empty and implanted in dog mandibles. The animals were followed for 4, 8, and 12 weeks, periotest assessment was performed at the end of each time interval, and specimens were collected for pullout biomechanical testing and radiographic evaluation of bone-implant contact levels.Results Periotest assessment did not provide evidence of statistically significant differences between the two groups and correlated well with the radiographic bone-implant contact levels. The pullout test revealed a higher correlation between force/displacement and displacement/energy for the experimental group, suggesting that the addition of rhBMP-2 did influence the rate of osseointegration.Conclusion The results from the pullout test support the potential role of rhBMP-2 in clinical applications by promoting a biomechanically mature interface at 12 weeks. However, radiographic and periotest assessment of the bone-implant interface did not provide evidence of the differences observed with biomechanical testing.This project is part of a dissertation prepared in partial fulfillment of Dr. Sykaras requirements for the degree of Doctor of Philosophy.     

Treatment of titanium dental implants with three piezoelectric ultrasonic scalers: an in vivo study

BACKGROUND: Dental implants require regular maintenance. It is crucial that the instrument used for maintenance be able to remove plaque and calculus from the implant surface effectively and efficiently, while causing minimal damage to its circumference. Some ultrasonic scalers may be useful for implant maintenance; however, no clinical study has examined this. This study evaluated the treatment of titanium implants with three piezoelectric scalers in vivo. METHODS: Fourteen patients underwent implant treatment in which plaque and calculus were removed from the abutment surfaces with ultrasonic scalers. The abutments were treated with scalers with carbon (VS; N = 7), plastic (PS; N = 7), or metallic (ES; N = 7) tips. The abutment surface characteristics were examined after instrumentation using scanning electron microscopy. The amount of plaque remaining and roughness were estimated using a modification of the remaining plaque and calculus score and the modified roughness score, respectively. In addition, the abutment surfaces were imaged with a laser profilometer and a laser scanning electron microscope (SEM). RESULTS: The remaining plaque and calculus scores did not differ significantly among the VS, PS, and ES groups. VS and PS produced a significantly smoother abutment surface than ES. The laser SEM three-dimensional images also demonstrated that VS and PS produced smooth abutment surfaces, whereas ES resulted in damaged surfaces. CONCLUSIONS: VS and PS produced clean, smooth abutment surfaces. Piezoelectric scalers with non-metal tips are suitable for use in dental implant maintenance.     

Surface treatments of titanium dental implants for rapid osseointegration.

The osseointegration rate of titanium dental implants is related to their composition and surface roughness. Rough-surfaced implants favor both bone anchoring and biomechanical stability. Osteoconductive calcium phosphate coatings promote bone healing and apposition, leading to the rapid biological fixation of implants. The different methods used for increasing surface roughness or applying osteoconductive coatings to titanium dental implants are reviewed. Surface treatments, such as titanium plasma-spraying, grit-blasting, acid-etching, anodization or calcium phosphate coatings, and their corresponding surface morphologies and properties are described. Most of these surfaces are commercially available and have proven clinical efficacy (>95% over 5 years). The precise role of surface chemistry and topography on the early events in dental implant osseointegration remain poorly understood. In addition, comparative clinical studies with different implant surfaces are rarely performed. The future of dental implantology should aim to develop surfaces with controlled and standardized topography or chemistry. This approach will be the only way to understand the interactions between proteins, cells and tissues, and implant surfaces. The local release of bone stimulating or resorptive drugs in the peri-implant region may also respond to difficult clinical situations with poor bone quality and quantity. These therapeutic strategies should ultimately enhance the osseointegration process of dental implants for their immediate loading and long-term success.     

A comparison of biocompatibility and osseointegration of ceramic and titanium implants: an in vivo and in vitro study

This study compared the biocompatibility in vitro and the osseointegration in vivo of zirconium and titanium implants regarding implant surfaces and the bone-implant contacts. The different implant surfaces and the biocompatibility of zirconium versus titanium implants were determined by vitality and cytotoxic tests in vitro. The contact of the osteoblasts to the implant surface was determined by scanning electron microscopy (SEM). The in vivo study for osseointegration was performed in domestic pigs over 4 and 12 weeks. In each animal, 4 zirconium and 4 titanium implants (WhiteSky, BlueSky, Bredent, Germany) were inserted in the os frontale and analysed by histomorphometry. Cytotoxicity and SEM showed good biocompatibility in relation to the investigated implant materials. Histological results showed direct bone-implant contact of the implant surfaces. The zirconium implants showed a slight delay in osseointegration in terms of bone-implant contact as measured by histomorphometry (after 4 weeks, zirconium (59.3 ± 4.6%) versus titanium (64.1 ± 3.9%); after 12 weeks, zirconium (67.1 ± 2.3%) versus titanium (73.6 ± 3.2%). A statistically significant difference between the two groups was not observed. The results indicated similar biocompatibility and osseointegration for zirconium compared to titanium implants.     

Early osseointegration driven by the surface chemistry and wettability of dental implants

Objective

The objective of this study was to investigate the impact of two different commercially available dental implants on osseointegration.

The surfaces were

sandblasting and acid etching (Group 1) and sandblasting and acid etching, then maintained in an isotonic solution of 0.9% sodium chloride (Group 2).

Material and Methods

X-ray photoelectron spectroscopy (XPS) was employed for surface chemistry analysis. Surface morphology and topography was investigated by scanning electron microscopy (SEM) and confocal microscopy (CM), respectively. Contact angle analysis (CAA) was employed for wetting evaluation. Bone-implant-contact (BIC) and bone area fraction occupied (BAFO) analysis were performed on thin sections (30 μm) 14 and 28 days after the installation of 10 implants from each group (n=20) in rabbits’ tibias. Statistical analysis was performed by ANOVA at the 95% level of significance considering implantation time and implant surface as independent variables.

Results

Group 2 showed 3-fold less carbon on the surface and a markedly enhanced hydrophilicity compared to Group 1 but a similar surface roughness (p>0.05). BIC and BAFO levels in Group 2 at 14 days were similar to those in Group 1 at 28 days. After 28 days of installation, BIC and BAFO measurements of Group 2 were approximately 1.5-fold greater than in Group 1 (p<0.05).

Conclusion

The surface chemistry and wettability implants of Group 2 accelerate osseointegration and increase the area of the bone-to-implant interface when compared to those of Group 1.     

紫外线光功能化对二氧化钛纳米管表面改性钛种植体骨结合的影响

目的 研究紫外线光功能化对二氧化纳米管钛表面改性钛种植体骨结合的影响。方法 采用预阳极氧化法制备二氧化钛（TiO₂）纳米管表面改性钛种植体，并用波长为250 nm、功率为2mW/cm²紫外线（UVA）对种植体进行处理。将种植体植入SD大鼠股骨，12周后取含种植体骨组织制作组织切片，通过显微镜观察种植体周围骨组织形成情况并计算骨结合率。结果UVA处理组种植体周围新生骨组织多于未UVA处理组，且更致密。UVA处理组和未UVA处理组的骨结合率分别为（72.21±10.42）%和（44.98±9.62）%，两组之间的差异具有统计学意义（P<.05）。结论UVA光功能化TiO₂纳米管表面改性有助于促进钛种植体骨结合。     

牙种植体周围骨缺损引导骨组织再生后骨结合的生物力学研究

目的:通过生物力学测试,观察、分析和评价两种异种骨移植材料在牙种植体周围骨缺损中引导骨组织再生后种植体与骨的结合强度,为临床应用提供参考。方法:成年比格犬两只,每只犬的四肢股骨中分别植入24枚种植体(每侧股骨6枚),共48枚。再用裂钻在近心端1--4号种植体远中制作一5mm直径的圆形骨缺损并分别用两种异种骨移植材料在牙种植体周围骨缺损中引导骨组织再生。手术后6个月处死动物。摄x线片观察,并用万能力学实验机通过推出、拉出实验测试种植体-骨结合力、通过扭矩实验测试种植体-骨界面的结合强度。结果:三组种植体和骨界面x线表现相似,均有新骨形成;Bio—OSS组骨的结合强度要略高于天博骨粉组,两者无显著性差异(P>0.05);但两者与正常对照组均有差异。结论:两种异种骨移植材料均可较好的引导种植体周围骨缺损中骨组织再生,但实验组与对照组的生物力学测试结果有显著性差异(P<0.01)。提醒我们在种植体周围骨缺损区引导组织再生后早期临床负载方式的选择仍需谨慎。     

Bone interface of dental implants cytologically influenced by a modified sandblasted surface: a preliminary in vitro study.

To study the influences of a modified sandblasted surface (developed by the authors) on the integrating status of titanium (Ti) dental implants and bone in vitro, a three-dimensional experimental model of implant material-osteoblast culture was used. The interaction of Ti discs and osteoblasts at the interface was followed with phase-contrast microscope examination and was further observed histologically and ultra-structurally after one-month culture. Results showed that there was no significant difference between the modified sandblasted surface group and the smooth surface group in the capacity of osteoblasts migrating and attaching to Ti discs. There was, however, a significant difference in the pattern of attachment. Around the polished surface, the migrating and attaching osteoblasts oriented themselves parallel to it; however, around the modified sandblasted surface, the osteoblasts were migrating and attaching perpendicularly. There was also a major difference in the shapes of cells lining the interface; spindle-shaped on the smooth surface versus round and ovoid with a large cellular body and abundant cytoplasm on the modified sandblasted surface. Moreover, transmission electron microscopy revealed an active secretion of collagen fibrils, a bone-matrix-vesicles-mediated mineralization process, and the formation of osteocytes in the modified sandblasted surface group. Therefore, at this in vitro level, it can be concluded that the modified sandblasting surface treatment of dental implants can facilitate bone healing at their osseous interface and enable the real perpendicularly connecting bone-fiber osseointegration to form instead of the capsule-like osseous adaptation.     

Short-term evaluation of dental implants in a diabetic population: an in vivo study

PURPOSE

The study was conducted to evaluate the efficacy of implant supported tooth replacement in diabetic patients.

MATERIALS AND METHODS

The study involved placement of implants (UNITI implants, Equinox Medical Technologies, Zeist, Holland, diameter of 3.7 mm and length 13 mm) in five diabetic patients (three females and two males) of age ranging from 35-65 years with acceptable metabolic control of plasma glucose. All patients included in the study were indicated for single tooth maxillary central incisor replacement, with the adjacent teeth intact. The survival of the restored implants was assessed for a period of three months by measurement of crestal bone heights, bleeding on probing and micro flora predominance. Paired t-test was done to find out the difference in the microbial colonization, bleeding on probing and crestal bone loss. P values of less than 0.05 were taken to indicate statistical significance.

RESULTS

Results indicated that there was a significant reduction in bleeding on probing and colonization at the end of three months and the bone loss was not statistically significant.

CONCLUSION

The study explores the hypothesis that patients with diabetes are appropriate candidates for implants and justifies the continued evaluation of the impact of diabetes on implant success and complications.     

The effect of low-intensity pulsed ultrasound on the osseointegration of titanium dental implants

Our aim was to record the effect of low-intensity pulsed ultrasound (LIPUS) on the osseointegration of endosseous dental implants in 10 New Zealand rabbits. One titanium implant with screw was inserted into the metaphyseal region of each femur and tibia in the knee joints of each rabbit, making a total of 40 implants. The area of one lateral knee joint, including implants, was irradiated with LIPUS for 10 min twice a day for 21 days. The other side acted as control, having been given "sham" irradiation. Two rabbits were killed at each of 0, 2, 4, 6, and 8 weeks after irradiation. A micro-computed tomogram (μCT), histological examination, and implant pull-out test were used to judge the reactions of the bone to the titanium implant. Histological and μCT examinations showed that osseointegration of the implants on the LIPUS-treated side happened earlier and more effectively than on the control side. The mechanical test showed that the maximal axial pull-out strength of the implants on the LIPUS-treated side was greater than that on the control side. We conclude that LIPUS has the potential to accelerate the osseointegration of dental implants.     

Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects

Objective: This study was designed to evaluate the effect of surface contamination on osseointegration of dental implants surrounded by a circumferential bone defect and to compare osseointegration around Osseotite® with that around Nanotite^? implants. Materials and methods: The premolars on both sides of the mandible in four beagle dogs were extracted. Following 4 months healing, two Nanotite^? implants and two Osseotite® implants were partially inserted in the left side of each mandible. Some threads protruded from the tissues into the oral cavity. Following a 5 week healing period, the implants were removed and the contaminated part of each implant was cleaned. They were then installed to the full implant length on the contra lateral side of the mandibles. The coronal 5 mm of each implant was surrounded by 1 mm circumferential bone defect. Following 12 weeks of healing period, the dogs were sacrificed and biopsies were obtained. Ground sections were prepared for histomorphometric analysis. Results: All implants were associated with direct bone‐to‐implant contact on the portion of the implant surface contaminated previously and surrounded by bone defect. Nanotite^? implants performed better than Osseotite® implants. Conclusions: The results demonstrated that implant surfaces, which were contaminated previously and were surrounded by bone defects, can osseointegrate. To cite this article:
Mohamed S, Polyzois I, Renvert S, Claffey N. Effect of surface contamination on osseointegration of dental implants surrounded by circumferential bone defects. Clin. Oral Impl. Res. 21 , 2010; 513–519.
doi: 10.1111/j.1600‐0501.2010.01913.x