Sandblasted and acid-etched dental implants: a histologic study in rats

PURPOSE: Current literature has revealed that surface etching of endosseous implants can improve bone-implant contact. The aim of this study was to evaluate the differences in bone-implant contact (BIC) between sandblasted/acid-etched and machined-surface implants. MATERIALS AND METHODS: Thirty-two Sprague-Dawley rats were used in this study. Two implant surfaces, Ecotek (sandblasted/ acid-etched) and machined, were used with 1 implant placed in each tibia of the animals. A total of 64 implants were placed. BIC was evaluated at 5, 15, 30, and 60 days. Histomorphometry of the BIC was evaluated statistically. RESULTS: The sandblasted/acid-etched surface demonstrated a greater BIC percentage than the machined surface. This difference was statistically significant only at 30 and 60 days after healing. DISCUSSION AND CONCLUSION: The sandblasted/acid-etched surface demonstrated a stronger bone response than the machined one at a later period of healing.     

Surface properties and biocompatibility of acid-etched titanium

The purpose of this study was to evaluate the effects of acid-etched titanium on the biological responses of osteoblast-like MC3T3-E1 cells. Four types of treatments (polishing, sandblasting, concentrated H2SO4 etching, and concentrated H2SO4 etching with vacuum firing) were carried out on the surfaces of commercially pure titanium (cpTi) disks. MC3T3-E1 cells were then cultured on the treated cpTi surfaces. Through surface roughness measurement and SEM analysis, it was found that the acid-etched surfaces showed higher roughness values than the sandblasted ones. Scanning electron microscope analysis showed that the cells on the disks treated with acid-etching and acid-etching with vacuum firing spread as well as the sandblasted ones. There were no significant differences in cell proliferation and collagen production on cpTi among the four different surface treatments. Based on the results of this study, it was concluded that etching with concentrated sulfuric acid was a simple and effective way to roughen the surface of titanium without compromising its biocompatibility.     

不同表面处理方法对CAD/CAM氧化锆种植体表面显微形貌的影响研究

目的：：研究采用不同表面处理方法对CAD/CAM氧化锆种植体表面显微形貌特征及粗糙度的影响。方法：通过CAD/CAM技术加工氧化锆圆盘与一段式氧化锆种植体( Y-TZP, WIELAND),根据表面处理方式分为终烧结表面、喷砂表面及喷砂加热酸蚀处理表面;标准对照组选用BEGO钛种植体表面。各组圆盘试件及种植体用扫描电子显微镜及Keyence 3D激光显微形貌测量显微镜进行表面显微形貌观察与测量。采用单因素方差分析比较各组统计学差异。结果：各组CAD/CAM氧化锆试件表面显微形貌观察显示,喷砂后表面出现边缘锐利的凹坑及沟槽;喷砂加热酸蚀处理后,氧化锆表面可见纳米级的微小孔隙及沟纹。氧化锆种植体粗糙度测量结果显示：终烧结组的表面粗糙度值(Ra=0.69μm)显著低于其他3组(P<0.001),喷砂组Ra值(Ra=1.30μm)显著低于喷砂加热酸蚀组(Ra=1.49μm)及BEGO钛种植体组(Ra=1.57μm)(P<0.01),而喷砂加热酸蚀组与BEGO钛种植体组则无显著差异(P=0.196)。结论：CAD/CAM氧化锆试件终烧结后喷砂或喷砂加热酸蚀处理均可获得较为理想的表面粗糙度,热酸蚀处理能够改变氧化锆表面的纳米级微观结构。     

A macro- and nanostructure evaluation of a novel dental implant

Success in implant dentistry also comes from the implant macrodesign and nanostructure of its surface. Titanium implant surface treatments have been shown to enhance osseointegration, maximize bone healing, and bone-to-implant contact for predictable clinical results. The aim of the study, was to evaluate the geometric macrodesign and the surface nanostructure of a novel dental implant full contact covering (FCC) obtained by electrochemical procedures. FCC implants were analyzed by scanning electronic microscope, profilometer, and x-ray photoelectron spectroscopy and compared with commercial sandblasted and sandblasted, large-grit acid-etched dental implants. Sample analysis allowed to distinguish the different implant macrodesigns, the step and the profile of the coils that cover the fixture, and the surface characteristics. FCC implant showed novel macro-characteristic of crestal module, coils, and apical zone compared with sandblasted and sandblasted and acid-etched dental implants. Moreover, the FCC nanostructure surface showed roughness values statistically higher than the 2 other surfaces, with a more homogeneity in a peaks and valleys arrangement. Finally, the x-ray photoelectron spectroscopy analysis detected differences between the examined surfaces, with the presence of several contaminants according to the different treatment procedures. Research on new macrostructures and nano morphology should result in a better qualitative and quantitative osseointegration response, with a predictability of the clinical results and long-term success of the implants.     

Early endosseous integration enhanced by dual acid etching of titanium: a torque removal study in the rabbit

Textured implant surfaces are thought to enhance endosseous integration. Torque removal forces have been used as a biomechanical measure of anchorage, or endosseous integration, in which the greater forces required to remove implants may be interpreted as an increase in the strength of bony integration. The purpose of this study was to compare the torque resistance to removal of screw-shaped titanium implants having a dual acid-etched surface (Osseotite) with implants having either a machined surface, or a titanium plasma spray surface that exhibited a significantly more complex surface topography. Three custom screw-shaped implant types - machined, dual acid-etched (DAE), and titanium plasma sprayed (TPS) - were used in this study. Each implant surface was characterized by scanning electron microscopy and optical profilometry. One DAE implant was placed into each distal femur of eighteen adult New Zealand White rabbits along with one of the other implant types. Thus, each rabbit received two DAE implants and one each of the machined, or TPS, implants. All implants measured 3.25 mm in diameter x 4.00 mm in length without holes, grooves or slots to resist rotation. Eighteen rabbits were used for reverse torque measurements. Groups of six rabbits were sacrificed following one, two and three month healing periods. Implants were removed by reverse torque rotation with a digital torque-measuring device. Three implants with the machined surface preparation failed to achieve endosseous integration. All other implants were anchored by bone. Mean torque values for machined, DAE and TPS implants at one, two and three months were 6.00+/-0.64 N-cm, 9.07+/-0.67 N-cm and 6.73+/-0.95 N-cm; 21.86+/-1.37 N-cm, 27.63+/-3.41 N-cm and 27.40+/-3.89 N-cm; and 27.48+/-1.61 N-cm, 44.28+/-4.53 N-cm and 59.23+/-3.88 N-cm, respectively. Clearly, at the earliest time point the stability of DAE implants was comparable to that of TPS implants, while that of the machined implants was an order of magnitude lower. The TPS implants increased resistance to reverse torque removal over the three-month period. The results of this study confirm our previous results that demonstrated enhanced bony anchorage to dual acid-etched implants as compared to machined implants. Furthermore, the present results indicate that dual acid etching of titanium enhances early endosseous integration to a level which is comparable to that achieved by the topographically more complex TPS surfaces.     

Radiologic follow-up of peri-implant bone loss around machine-surfaced and rough-surfaced interforaminal implants in the mandible functionally loaded for 3 to 7 years

PURPOSE: In this retrospective study, marginal peri-implant bone height around machined and sandblasted/acid-etched interforaminal implants in the mandible was evaluated radiologically at least 3 years after functional loading. MATERIALS AND METHODS: Fifty-one patients, each with 4 interforaminal screw-type implants placed between 1994 and 1998, were included in this study. Of these, 36 patients (70.6%) with a total of 144 implants (76 machined Mk II implants and 68 sandblasted/acidetched Frios implants) were available for follow-up studies. Interforaminal marginal bone loss was evaluated by extraoral rotational panoramic radiographs. In addition, predictive factors such as patient age and sex, nicotine use, implant position, implant life, and site of measurement were recorded, as well as bone loss at surgery (ie, baseline bone loss). Analysis of covariance for repeated measurements was used for statistical analysis. Between-group differences were expressed as least square means +/- standard error. RESULTS: Sandblasted/acid-etched implants showed significantly less marginal bone loss than machine-surfaced implants (2.4 +/- 0.23 mm vs 1.64 +/- 0.27 mm). Implants placed in the anterior of the arch showed significantly more peri-implant bone loss than implants placed in the posterior (P = .0001). DISCUSSION AND CONCLUSIONS: Significantly less long-term peri-implant bone loss was observed for rough implant surfaces compared to machine-surfaced implants. However, it was also demonstrated that both types of implants, in combination with bar-supported overdentures, can produce excellent long-term results in the atrophic edentulous mandible. Mesially placed implants showed more bone resorption than distally positioned implants, independent of surface roughness.     

Histologic evaluation of human bone integration on machined and sandblasted acid-etched titanium surfaces in type IV bone

The aim of this preliminary study was to evaluate the influence of a sandblasted acid-etched surface on bone-implant contact percentage (BIC%) as well as the bone density in the threads area (BD%) in type 4 bone after 2 months of unloaded healing. Five subjects (mean age = 42.6 years) received 2 microimplants each during conventional implant surgery in the posterior maxilla. The microimplants with commercially pure titanium surface (machined) and sandblasted acid-etched surface served as the control and test surfaces, respectively. After a healing period of 2 months, the microimplants and the surrounding tissue were removed and prepared for ground sectioning and histomorphometric analysis. One microimplant with a machined surface was found to be clinically unstable at the time of retrieval. Histometric evaluation indicated mean BIC% was 20.66+/-14.54% and 40.08+/- 9.89% for machined and sandblasted acid-etched surfaces, respectively (P=.03). The BD% was 26.33 +/-19.92% for machined surface and 54.84+/-22.77% for sandblasted acid-etched surface (P=.015). Within the limits of this study, the data suggest that the sandblasted acid-etched implant surface presented a higher percentage of bone-implant contact compared with machined surfaces, under unloaded conditions in posterior maxilla after a healing period of 2 months.     

Harder and stiffer bone osseointegrated to roughened titanium

Mechanisms underlying the beneficial anchorage of roughened titanium implants have not been identified. We hypothesized that the implant surface roughness alters intrinsic biomechanical properties of bone integrated to titanium. Nano-indentation performed on two- and four-week post-implantation bone specimens of rats revealed that bone integrated to acid-etched titanium was approximately 3 times harder than that integrated to the machined titanium, both at the osseointegration interface and at the inner area of the peri-implant bone. The hardness of the acid-etched surface-associated bone was equivalent to that of untreated cortical bone at week 4, while the bone hardness around the machined surface was equivalent to that of the untreated trabecular bone. The elastic modulus of the integrated bone was 1.5 to 2.5 times greater around the acid-etched surface than around the machined surface. Analysis of the data suggests that the implant surface roughness affects the biomechanical quality of osseo-integrated bone, and that the bone integrated to the acid-etched surface is harder and stiffer than the bone integrated to the machined surface.     

Effects of implant microtopography on osteoblast cell attachment

PURPOSE: The overall aim of this project was to study osteoblast cell attachment on titanium surfaces with varying surface roughness. MATERIALS AND METHODS: Commercially pure titanium surfaces were prepared by polishing through 600-grit sandpaper, sandblasting, or sandblasting followed by acid etching to produce surfaces of varying roughness, as determined by scanning electron microscopy and atomic force microscopy. In vitro cell attachment of MC3T3-E1 osteoblasts was performed on the prepared surfaces in both serum-containing and serum-free media conditions. RESULTS: Cell attachment was directly related to the average surface roughness, with the highest levels of cell attachment observed on sandblasted and sandblasted-acidetched surfaces. Similar patterns of cell attachment were observed when serum-free conditions were employed. CONCLUSIONS: Combined surface analytical and cell/molecular biological techniques are powerful tools to broaden our understanding of biological events occurring at the implant-tissue interface. Data acquired from these in vitro techniques provide a translational application to in vivo clinical models leading to the next generation of dental implants.     

Histologic evaluation of early human bone response to different implant surfaces

BACKGROUND: Studies have demonstrated that roughened dental implant surfaces show firmer bone fixation and an increased percentage of bone-to-implant contact (BIC%) compared to commercially pure titanium-surface (machined) implants. Therefore, the purpose of this study was to evaluate the influence of implant-surface topography on human bone tissue after 2 months of unloaded healing. METHODS: Fourteen subjects with a mean age of 46.87 +/- 9.45 years received two microimplants each (2.5 mm in diameter and 6 mm in length), one test (sandblasted acid-etched surface) and one control (machined surface), either in the mandible or in the maxilla. After a healing period of 2 months, the microimplants and surrounding tissues were removed with a trephine bur and prepared for histologic analysis. RESULTS: All microimplants, except for one of the controls, were clinically stable after the healing period. Histometric evaluation indicated that the mean BIC% was 23.08% +/- 11.95% and 42.83% +/- 9.80% for machined and rough microimplant surfaces, respectively (P = 0.0005). The bone area within the threads was also higher for sandblasted-surface implants (P = 0.0005). The mean percentage of bone density did not differ between the two groups (P = 0.578). CONCLUSION: Data from the present histological study suggest that the sandblasted acid-etched implant provides a better human bone tissue response than machined implants under unloaded conditions after a healing period of 2 months.     

Osseointegration enhanced by chemical etching of the titanium surface. A torque removal study in the rabbit.

Roughened implant surfaces are thought to enhance osseointegration. Torque removal forces have been used as a biomechanical measure of anchorage or osseointegration in which the greater forces required to remove implants may be interpreted as an increase in the strength of osseointegration. The purpose of this study was to compare the torque resistance to removal of screw shaped titanium implants having an acid etched (HCl/H₂SO₄) surface (Osseotite®) with implants having a machined surface. Two custom screw shaped implants, 1 acid etched and the other machined, were placed into the distal femurs of 10 adult New Zealand White rabbits. These implants were 3.25 mm in diameter x 4.00 mm in length without holes, grooves or slots to resist rotation. Following a 2 month healing period, the implants were removed under reverse torque rotation with a digital torque measuring device. Two implants with the machined surface preparation failed to achieve osseointegration. All other implants were found to be anchored to bone. Resistance to torque removal was found to be 4 x greater for the implants with the acid etched surface as compared to the implants with the machined surface. The mean torque values were 20.50 ± 6.59 N cm and 4.95 ± 1.61 N cm for the acid etched and machined surfaces respectively. The results of this study suggest that chemical etching of the titanium implant surface significantly increases the strength of osseointegration as determined by resistance to reverse torque rotation.     

Bone response to modified titanium surface implants in nonhuman primates (Papio ursinus) and humans: histological evaluation

The aim of this study is a comparative histological and histomorphometrical evaluation of the effect on early bone formation of 2 different implant surfaces: a machined and a new acid-etched implant surface (Leader, Milano, Italy). Ten screw-type microimplants were placed in 5 patients. Each patient received 2 microimplants (2 mm in diameter and 5 mm in length): 1 with a machined surface (control) and 1 with an acid-etched surface (test). The microimplants were retrieved after 60 days of healing with a 4-mm trephine bur and processed for histology. Moreover, 24 regular size implants--12 with a machined surface (control) and 12 with an acid-etched surface (test)--were placed in 2 adult nonhuman primates 3 months after the extraction of premolars and molars. Each animal received 3 machined implants (control) in the right hemimandible and 3 acid-etched implants (test) in the left hemimandible. The same animals received 3 control implants and 3 test implants in the rectus abdominis muscle. After 1 month, the implants were retrieved from the mandible and the rectus abdominis muscle and processed for histology. Histomorphometric evaluation demonstrated a higher bone-to-implant contact in the test implants compared with the controls in both primates (25.55% vs 15.8%) and humans (62% vs 45%). Moreover, in nonhuman primates after 1 month of healing, it was possible to observe a poor osseointegration in the control specimens, while newly formed bone in direct contact with test implants was evident. The rectus abdominis muscle specimens showed that the acid-etched surfaces can stimulate the formation and attachment of new connective and vascular tissues more than machined surfaces can. Implant surface geometry can speed up bone formation by the development of a special microenvironment that promotes angiogenesis. Long-term studies are needed to further test this new acid-etched implant surface.     

Behavior of CAL72 osteoblast-like cells cultured on zirconia ceramics with different surface topographies

OBJECTIVES: Because of its inherent strength, biocompatibility, and tooth-like color, zirconia ceramics have the potential to become an alternative to titanium as dental implant material. This study aimed at investigating the osteoblastic response to yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) with different surface topographies. METHODS: CAL72 osteoblast-like cells were cultured on machined (TZP-m), airborne particle abraded (TZP-s), and airborne particle abraded and acid-etched Y-TZP (TZP-sa) surfaces. Polystyrene and airborne particle abraded with large grit and acid-etched (SLA) titanium served as a reference control. The surface topography was examined by scanning electron microscopy (SEM) and profilometry. At culture days 3, 6, and 12, cell proliferation, at day 12 cell morphology, and cell-covered surface area were determined. RESULTS: The surface roughness of Y-TZP was increased by airborne particle abrasion and additionally by acid etching. No statistically significant differences were found between average roughness (R(a)) and maximum peak-to-valley height (R(p-v)) values of airborne particle abraded and acid-etched Y-TZP and SLA titanium. Whereas the cell proliferation assay revealed statistically significant greater values at day 3 for surface-treated Y-TZP and polystyrene cultures as compared with machined Y-TZP, no differences between the Y-TZP groups, SLA titanium, and polystyrene were observed at culture days 6 and 12. CONCLUSIONS: Cell morphology and cell-covered surface area were not affected by the type of substrate. The results suggest that roughened Y-TZP is an appropriate substrate for the proliferation and spreading of osteoblastic cells.     

不同钛表面形貌对人牙龈成纤维细胞生物学行为的影响

目的:良好的种植体颈部软组织封闭是种植体远期成功的重要因素之一。生物封闭的的主要决定因素之一是种植体颈部的表面形貌。本实验的目的是通过比较三种不同的纯钛表面形貌结构对人牙龈成纤维细胞的生物学行为的影响,寻找一种有利于牙龈胶原纤维附着的较理想的种植体颈部表面形貌,为种植体颈部设计提供指导。方法:本研究采用机械加工处理、电化学腐蚀、电化学腐蚀加酸蚀的方法在纯钛金属表面形成三组不同的表面形貌结构;用激光共聚焦显微镜检测其表面粗糙度;扫描电镜观察其表面微观形态并用X射线能谱色散谱仪检测其表面成分;将其与人牙龈成纤维细胞共同培养,MTT法检测表面细胞的增殖情况;细胞计数仪进行表面细胞计数;扫描电镜观察表面细胞的形状及排列。结果:机械加工组表面较光滑,呈浅的等向排列的微沟纹,表面粗糙度Sa为0.8783±0.2578μm;电化学腐蚀组表面略粗糙,呈圆形或椭圆形浅碟状凹,直径约10～15μm,分布均匀,凹内含有散在的小孔,小孔的直径约为1-5μm,表面粗糙度Sa为1.7530±0.3711μm;电化学腐蚀加酸蚀组表面略粗糙,呈圆形或椭圆形浅碟状凹,直径约10～15μm,分布均匀,凹内含有散在的小孔,小孔的直径约为1-5μm,表面见均匀的半球形纳米突起形成,直径约50～100nm,表面粗糙度Sa为1.6763±0.3440μm。表面成分检测显示三组均未有任何污染物在钛表面。牙龈成纤维细胞在各组钛片表面生长良好,形态正常,各组钛片对于细胞没有明显的毒性,生长曲线与正常细胞的生长曲线规律一致。机械加工组表面细胞沿着材料表面微沟纹平行排列,细胞扁平,伸展较差,细胞伸出的伪足较短;电化学腐蚀组表面细胞自由分布,细胞丰满,伸展良好,细胞伸出的伪足较长,有的伪足伸入到邻近凹内;电化学腐蚀加酸蚀组表面细胞丰满,伸展良好,伸出大量伪足,伪足很长,呈细丝状或带状,可伸入到相隔较远的凹孔内,呈悬空样,也可相互交织成网状。结论:电化学腐蚀加酸蚀可在纯钛表面形成均匀分布的直径为10-20μm的凹及直径为1-5μm的孔,凹及孔的表面均匀布满了直径为50-100nm的半球状突起。电化学腐蚀加酸蚀表面促成纤维细胞粘附作用最强。本实验中形成的微米凹、孔形态及半球形纳米形态均有利于成纤维细胞的粘附。电化学腐蚀加酸蚀方法形成的表面是一种较为理想的种植体颈部表面,可以为种植体颈部设计提供指导。     

Surface chemistry effects of topographic modification of titanium dental implant surfaces: 1. Surface analysis

PURPOSE: To analyze the surface composition of 34 different commercially available titanium dental implants. MATERIALS AND METHODS: Surface composition was evaluated by x-ray photoelectron spectroscopy (XPS). Samples were divided into 4 groups, depending on their surface topography (machined, sandblasted, acid etched, or plasma sprayed). RESULTS: Statistical analysis of the data showed a clear relationship between surface composition and topography, which can be easily accounted for by the chemical effects of the surface treatment performed. On average, acid-etched and plasma-sprayed surfaces had higher titanium and lower carbon concentration than machined surfaces. DISCUSSION AND CONCLUSION: Current studies aimed at the evaluation of implants with different topography should not implicitly assume that topography is the only variable controlling the biologic response. Rather, when comparing different topographies, it should be taken into account that surface chemistry may be a variable as well.     

Spreading of epithelial cells on machined and sandblasted titanium surfaces: an in vitro study

BACKGROUND: The purpose of this investigation was to determine the influence of the surface structure of dental implants on epithelial cell spreading and growth in vitro. Cell morphology on machined and sandblasted titanium surfaces was investigated. METHODS: A total of 10 machined and 10 sandblasted discs and 10 glass coverslips were used for the present study. Samples were analyzed using scanning electron microscopy (SEM) and the cell spreading area was determined using a video image analysis system. RESULTS: After 24 hours incubation, keratinocytes grown on sandblasted titanium samples displayed numerous, long, and branched or dendritic filopodia closely adapted to the surface roughness. Filopodia varied from 3 to 12 microm in length and 0.1 to 0.3 microm in width. Cells cultured on a machined surface did not present such cytoplasmic extensions and displayed a round morphology. Keratinocytes seeded on glass coverslips were flat and edged by filopodia (maximum length 7 to 8 microm) on the spreading site of the cluster. Though cell morphology is comparable with that observed on sandblasted specimens, cytoplasmic extensions suggestive of strong adhesion and spreading attitude were less pronounced. CONCLUSION: These results indicate that sandblasted surfaces are the optimal substrata for epithelial cell adhesion and spreading.     

Nano-crystalline diamond-coated titanium dental implants – A histomorphometric study in adult domestic pigs

Promising biomaterial characteristics of diamond-coatings in biomedicine have been described in the literature. However, there is a lack of knowledge about implant osseointegration of this surface modification compared to the currently used sandblasted acid-etched Ti-Al6-V4 implants. The aim of this study was to investigate the osseointegration of microwave plasma-chemical-vapour deposition (MWP-CVD) diamond-coated Ti-Al6-V4 dental implants after healing periods of 2 and 5 months.Twenty-four MWP-CVD diamond-coated and 24 un-coated dental titanium-alloy implants (Ankylos^®) were placed in the frontal skull of eight adult domestic pigs. To evaluate the effects of the nano-structured surfaces on bone formation, a histomorphometric analysis was performed after 2 and 5 months of implant healing. Histomorphometry analysed the bone-to-implant contact (BIC). No significant difference in BIC for the diamond-coated implants in comparison to reference implants could be observed for both healing periods. Scanning electron microscopy revealed an adequate interface between the bone and the diamond surface. No delamination or particle-dissociation due to shearing forces could be detected. In this study, diamond-coated dental titanium-alloy implants and sandblasted acid-etched implants showed a comparable degree of osseointegration.