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.     

Improved retention and bone-tolmplant contact with fluoride-modified titanium implants

PURPOSE: The purpose of the present study was to investigate whether a fluoride modification of the titanium surface would have an effect on bone response after implantation. MATERIALS AND METHODS: Titanium-oxide-blasted titanium implants with and without fluoride modification were investigated in a rabbit tibia model. Quantitative analysis of surface roughness, biomechanical interlocking, and in vivo tissue reactions in rabbit bone at 1 and 3 months after placement were compared. RESULTS: The fluoride-modified test implants had a slightly smoother surface (Sa: 0.91 +/- 0.14 microm) than the unmodified control implants (Sa: 1.12 +/- 0.24 microm). Significantly higher removal torque values (85 +/- 16 Ncm vs 54 +/- 12 Ncm) and shear strength between bone and implants (23 +/- 9 N/mm2 vs 15 +/- 5 N/mm2) were measured for the fluoride-modified implants after 3 months. The histomorphometric evaluations demonstrated higher bone-to-implant contact for test implants at 1 month (35% +/- 14% vs 26% +/- 8%) and 3 months (39% +/- 11% vs 31% +/- 6%) after placement. DISCUSSION: Implant surface modification with fluoride may result in morphologic and physiochemical phenomena that are of significance for the bone response. Another possible explanation for the findings in the present study is that a surface modification changes the surface chemical structures to be more suitable for bone bonding. CONCLUSION: Based on the biomechanical and histomorphometric data, the fluoride-modified titanium implants demonstrated a firmer bone anchorage than the unmodified titanium implants. These implants achieved greater bone integration than unmodified titanium implants after a shorter healing time.     

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.     

Removal torque and histomorphometric investigation of 4 different titanium surfaces: an experimental study in the rabbit tibia

This study presents a histomorphometric and biomechanical comparison of bone response to commercially pure titanium screws with 4 different types of surface topographies placed in the tibial metaphysis of 12 rabbits. Each rabbit had 4 implants placed, 2 in each tibia. The 4 surface topographies were a machined surface, a grit-blasted surface, a plasma-sprayed surface, and an acid-etched (Osseotite) surface. After a healing period of 5 weeks, histomorphometric and removal torque data revealed a significantly higher percentage of bone-to-implant contact and removal torque for acid-etched implants compared to machined, blasted, and plasma-sprayed implants. Within the limits of this short-term experimental study, the results indicated that micro-rough titanium surfaces obtained with acid-etching procedures achieved a 33% greater bone-to-implant contact over machined titanium surfaces with an abutment-type roughness and provided enhanced mechanical interlocking.     

Biomechanical evaluation of osseous implants having different surface topographies in rats

Biomechanical and biological factors can co-dependently influence the establishment of implant-tissue integration; thus, concurrent evaluation of these factors should provide a better understanding of osseointegration. This study aimed to establish and validate an in vivo rat model frequently used in molecular/cellular biology for implant biomechanical studies. We tested the hypotheses that the implant push-in test assesses the degree of osseointegration by the breakpoint load at the implant-tissue interface and that it sensitively differentiates between the effects of different implant surface topographies. The implant push-in test, which produces a consistent load-displacement measurement, was used to test miniature cylindrical titanium implants placed at the distal edge of the adult rat femur. The push-in test values obtained at each post-implantation healing point (weeks 0, 2, 4, and 8) significantly increased in a time-dependent manner. The implant surface after the push-in test was associated with remnant tissues containing host-derived elements, such as calcium, phosphate, and sulfate. In this model, acid-etched implants (average roughness, 0.159 microm) showed significantly greater push-in test values than did turned implants (average roughness, 0.063 microm) throughout the experimental period (p < 0.0001). These results support the validity of the push-in test in rats, which may be used as a rapid and sensitive biomechanical assay system for implant osseointegration research.     

Influence of titanium surface roughness on attachment of Streptococcus sanguis: an in vitro study

The purpose of the present study was to investigate the efficacy of the decontamination protocol for bacterial removal in titanium surfaces with three different levels of roughness using a high-pressure sodium bicarbonate device for 1 minute under aseptic conditions. Group 1 was composed of 10 as-machined titanium sheets and Groups 2 and 3 of titanium sheets blasted with aluminum oxide (Al2O3, alumina) particles with different diameters: Group 2 was blasted with 65-microm particles and Group 3 with 250-microm particles. The titanium specimens were sterilized and incubated in tubes containing a suspension of Streptococcus sanguis. The colony-forming units were counted before and after the application of the decontamination protocol. The arithmetic mean roughness (R(a)) per group was: Group 1, 0.17 microm +/- 0.01; Group 2, 1.14 microm +/- 0.15; and Group 3, 3.17 microm +/- 0.23. After the contamination period, Group 1 remained with 49 x 10(3) bacterial cells, and the bacterial concentrations of Groups 2 and 3 were 11 x 10(4) and 35 x 10(5), respectively. After the application of the decontamination protocol, no viable bacteria were detected. With the increase of the surface roughness, an exponential increase in bacterial cells was observed. The results showed that the decontamination protocol treatment with a high-pressure sodium bicarbonate device efficiently removed all bacterial cells in all surfaces tested. This indicates that high-pressure sodium bicarbonate spray should be used in the maintenance phase of implant treatment.     

Characterization of five different implant surfaces and their effect on osseointegration: a study in dogs

Background: Chemical modification of implant surface is typically associated with surface topographic alterations that may affect early osseointegration. This study investigates the effects of controlled surface alterations in early osseointegration in an animal model. Methods: Five implant surfaces were evaluated: 1) alumina‐blasting, 2) biologic blasting, 3) plasma, 4) microblasted resorbable blasting media (microblasted RBM), and 5) alumina‐blasting/acid‐etched (AB/AE). Surface topography was characterized by scanning electron microscopy and optical interferometry, and chemical assessment by x‐ray photoelectron spectroscopy. The implants were placed in the radius of six dogs, remaining 2 and 4 weeks in vivo. After euthanization, specimens were torqued‐to‐interface failure and non‐decalcified‐processed for histomorphologic bone–implant contact, and bone area fraction–occupied evaluation. Statistical evaluation was performed by one‐way analysis of variance (P <0.05) and post hoc testing by the Tukey test. Results: The alumina‐blasting surface presented the highest average surface roughness and mean root square of the surface values, the biologic blasting the lowest, and AB/AE an intermediate value. The remaining surfaces presented intermediate values between the biologic blasting and AB/AE. The x‐ray photoelectron spectroscopy spectra revealed calcium and phosphorus for the biologic blasting and microblasted RBM surfaces, and the highest oxygen levels for the plasma, microblasted RBM, and AB/AE surfaces. Significantly higher torque was observed at 2 weeks for the microblasted RBM surface (P <0.04), but no differences existed between surfaces at 4 weeks (P >0.74). No significant differences in bone–implant contact and bone area fraction–occupied values were observed at 2 and 4 weeks. Conclusion: The five surfaces were osteoconductive and resulted in high degrees of osseointegration and biomechanical fixation.     

Determining optimal surface roughness of TiO(2) blasted titanium implant material for attachment, proliferation and differentiation of cells derived from human mandibular alveolar bone

In the complex process of bone formation at the implant-tissue interface, implant surface roughness is an important factor modulating osteoblastic function. In this study, primary cultures of osteoblast-like cells, derived from human mandibular bone, were used. The aim was to examine the effect of varying surface roughness of titanium implant material on cellular attachment, proliferation and differentiation. A recognized method of increasing surface roughness and enlarging the surface area of titanium implants is by blasting with titanium dioxide particles: the four specimen types in the study comprised surfaces which were machine-turned only, or blasted after turning, with 63-90 microm, 106-180 microm, or 180-300 microm TiO(2) particles, respectively. The specimens were analyzed by scanning electron microscopy and confocal laser scanning. The turned samples had the smoothest surfaces: average height deviation (S(a)) of 0.20 microm. The roughest were those blasted with 180-300 microm particles, S(a) value 1.38 microm. Blasting with intermediate particle sizes yielded S(a) values of 0.72 microm and 1.30 microm, respectively. Cell profile areas were measured using a semiautomatic interactive image analyzer. Figures were expressed as percentage of attachment. DNA synthesis was estimated by measuring the amount of [(3)H]-thymidine incorporation into trichloroacetic acid (TCA) insoluble cell precipitates. The specific activity of alkaline phosphatase was assayed using p-nitrophenylphosphate as a substrate. The ability of the cells to synthesize osteocalcin was investigated in serum-free culture medium using the ELSA-OST-NAT immunoradiometric kit. After 3 h of culture, the percentage of cellular attachment did not differ significantly between specimens blasted with 180-300 micromparticles and the turned specimens. All blasted surfaces showed significantly higher [(3)H]-thymidine incorporation than the turned surfaces (P<0.05), with the highest on the surfaces blasted with 180-300 microm particles. Osteocalcin synthesis by the cells in response to stimulation by 1,25(OH)2D3, was also significantly greater (P<0.05) on the surfaces blasted with TiO(2) particles. However, analysis of alkaline phosphatase activity disclosed no significant differences among the four surface modifications. It is concluded that in this cellular model, the proliferation and differentiation of cells derived from human mandibular bone is enhanced by surface roughness of the titanium implant. However, increasing the size of the blasting particles to 300 microm does not further increase the initial attachment of the cells compared to turned surfaces and those blasted with 63-90 microm particles.     

Influence of parameters on root surface roughness following treatment with a magnetostrictive ultrasonic scaler: an in vitro study

BACKGROUND: This in vitro study aimed to evaluate the influence of different parameters, i.e., lateral force, instrument power setting, and the shape of the working tip, on the roughness of root surfaces following treatment with a magnetostrictive ultrasonic scaling device. METHODS: The study sample comprised a total of 102 extracted human molars, premolars, canines, and incisors. The samples were randomly divided into 10 equal units of 10 each for treatment with the ultrasonic device at a lateral force of 0.5 N and 2.0 N, a low and high instrument power setting, and with a straight and angulated shaped working tip. Twenty samples were treated manually using curets at a lateral force of 0.5 N and 2.0 N. Two samples were left untreated as controls. The mean (Ra) and maximum (Rmax) surface roughness of each sample was recorded. The statistical analysis was performed using analysis of variance (three-way ANOVA) at a level of significance of 5% (P < 0.05). RESULTS: The mean surface roughness (+/-SD) using different parameters ranged from 0.6 +/- 0.1 microm to 1.8 +/- 0.3 microm. The maximum surface roughness (+/-SD) was between 4.8 +/- 1.3 microm and 17.2 +/- 4.3 microm. The mean surface roughness (+/-SD) for samples treated with curets at a lateral force of 0.5 N was 0.5 +/- 0.0 microm and 0.4 +/- 0.1 microm at 2.0 N. The maximum surface roughness (+/-SD) was 3.7 +/- 0.8 microm at 0.5 N and 3.9 +/- 1.4 microm at 2.0 N. CONCLUSIONS: The findings of the present study indicate that the shape of the working tip and the lateral force significantly influence the mean and maximum surface roughness of root surfaces treated with a magnetostrictive ultrasonic scaling device. At any specific parameter, the surface roughness was significantly higher for the ultrasonic scaling device as compared to the hand curet.     

Evaluation of a predictive model for implant surface topography effects on early osseointegration in the rat tibia model

STATEMENT OF PROBLEM: Alterations in commercially pure titanium (cp Ti) implant surface topography can be made to increase bone formation or the interfacial shear strength of bone at the functioning implant. It is not known whether these 2 goals are congruent or mutually exclusive. PURPOSE: The aim of this study was to determine the effect of implant surface topography parameters of calculated biomechanical significance on the process of bone formation in a rat tibia model of osseointegration. MATERIAL AND METHODS: Implants (cp Ti grade IV) were machined and subsequently treated by grit blasting or grit blasting and 6.4 mol/L HCl. Measurements of surface roughness were made by atomic force microscopic analysis of similarly treated titanium disks. Cleaned and sterilized implants (12 machined, 12 with nonideal pit morphology, 12 with ideal pit morphology) were placed into the tibiae of 400-g male Wistar rats by using a series of drills, irrigation, and a self-tapping procedure. After 3 weeks, tibiae were harvested and processed and embedded in methyl methacrylate resin. Polished sections were examined by backscatter electron microscopy, and the percentage implant surface contacting bone was measured with the Scionics PC image analysis program. RESULTS. The implants possessing a proposed ideal pit morphology supported significantly greater bone formation at the implant surface (54% +/- 7% bone-to-implant contact [P<.003]) than the nonideal pit morphology (40% +/- 15%) or machined surfaces (34% +/- 6%). CONCLUSION: Implant surfaces with a proposed ideal pit morphology (which possess a calculated biomechanical significance) enhanced bone formation at early periods after placement in the rat tibia model.     

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.     

骨质疏松状态下牙种植体骨髓整合改变的实验研究

目的:探索骨质疏松状态下牙种植体骨整合的变化机制,为提高骨质疏松状态下牙种植体成功率奠定基础。材料与方法:6月龄未交配SD雌性大鼠41只随机分为2组,即A:假去势手术组,20只,B:去势手术组,21只。将B组行卵巢切除术,术后1.5月对所有大鼠右股骨远中行牙种植手术,种植纯钛螺钉。分别于种植术后1.5月及3月,随机处死各组大鼠的一半。去势术前、种植术前及处死前分别测量大鼠腰椎3—5、左右股骨远中1/2骨密度。处死后,取右股骨对种植部位进行X线拍片,然后将右股骨沿种植体长轴剖成两半,做扫描电镜观察种植体与骨结合状况,进行骨接触率的测定。结果:1.骨密度:两组大鼠腰椎、左右股骨远中骨密度去势术前大致相同,无显著差异。种植手术前,A组基本保持不变,B组显著降低。1.5月及3月处死时,A组仍基本保持不变,B则持续显著降低。2.骨融合指数(OI):1.5月及3月处死时,A组大于B组,统计分析,差异显著。各组大鼠不同时期处死时,骨融合指数大致相同,统计分析无显著差异。结论:1.不同骨密度下骨整合状况不同,骨密度高,骨整合状况好。2.种植体-骨界面新骨形成后,在没有外界因素作用情况下,延长时间骨整合状况改善不明显。3.骨质疏松改变可使大鼠种植体—骨界面骨融合指数降低。     

The role of surface roughness in promoting osteointegration

Scientific evidence that has been gathered in the past 20 years established that certain endosseous dental implants--primarily screw-type implants made of commercially pure titanium can be successfully utilized as anchorage for dental prostheses. In recent years, an effort has been made to simplify the surgical procedure, in order to modify clinical treatment modalities. One of the trends is to increasingly utilize microrough titanium implants. Roughened implant surfaces have a long history in implant dentistry, and the most prominent surface is titanium plasma-sprayed (TPS). In recent years new implant surfaces have emerged, so-called microrough titanium surfaces produced with reducing techniques such as grit-blasting with Al2O3 or TiO2 particles, sandblasting and acid-etching, or acid-etching alone. These different titanium surfaces have been tested in numerous in-vivo studies utilizing different animal models. Summarizing the results of these studies, it can be concluded that there is currently sufficient evidence that titanium implants with a microrough surfaces achieve a faster bone integration, a higher percentage of Bone implant Contact (BIC), and a higher resistance to shear documented with higher Removal Torque Values (RTV) when compared with titanium implants with a polished or machined surface. In order to understand the mechanism through which surface roughness modulates its effects mentioned above, recent studies used in-vitro experimental methods to study cell response to implant surface topography. These studies have shown that osteoblasts are sensitive to surface roughness, exhibiting decreased proliferation and a more differentiated phenotype on rougher surfaces. PGE2 production is enhanced on rough surfaces, as is the production of TGF beta 1, suggesting that surface roughness can mediate autocrine and paracrine regulation of osteogenesis. Moreover, surface roughness was found to modulate the effect of systemic hormones like 1,25-(OH)2D3 on osteoblasts. The clinical advantages of implants with rough surface were observed in recently conducted clinical trials. It was found, in humans, that roughened titanium implants need shorter healing period before loading, 6-8 (SLA and Osseotite respectively) weeks instead of 12 weeks. The clinical advantages of shorter healing periods are obvious. Moreover, it was found that certain roughened implants can be used in shorter sizes (6-8 mm) then accepted today. The utilization of shorter implants offers the avoidance of extensive surgical procedures such as nerve lateralization in the mandible or sinus grafting in the maxilla. However, sufficient long term documentation is still lacking, and the predictability of such modalities has yet to be examined in long term prospective clinical trials.     

The treatment of uncoated and titanium nitride-coated abutments with different instruments

PURPOSE: The aim of this in vitro study of titanium abutments was to investigate the extent of treatment traces, the roughness depth, and the quantity of titanium or, in the case of coated abutments, titanium nitride (TiN) removed from the surface after treatment with various instruments. MATERIALS AND METHODS: Eleven uncoated, mechanically smoothed abutments and 11 TiN-coated abutments were used. The abutments were treated with titanium, steel, and plastic curettes; a rubber cup; an ultrasonic scaler with a steel tip; and an air scaler and cleaning powder. There were two 2 x 2-mm test fields on each abutment; each was subjected to standardized treatment with an instrument. The untreated surfaces of each abutment served as controls. The roughness depth (Rz) and profile height of treated and untreated surfaces were measured with a profilometer; profile height served as a basis for determining the amount of substance removed by treatment. The treatment traces were analyzed by scanning electron microscopy and light microscopy. RESULTS: Both the ultrasonic scaler and the steel and titanium curettes left pronounced traces on the uncoated abutments and increased Rz. Substantial substance removal was recorded following the use of the ultrasonic scaler (17.57 +/- 2.87 microm) and the steel curettes (8.48 +/- 2.81 microm) on the uncoated abutments. In tests of the coated abutments, measurable substance removal (4.80 +/- 0.99 microm) and increased roughness depth were noted only with use of the steel curettes. The treatment traces left by the other instruments were distinctly less pronounced than on the uncoated abutments. Light microscopy revealed detachment of the TiN coating after use of the ultrasonic scaler, titanium curettes, and steel curettes. Slight to moderate treatment traces were recorded after use of the rubber cup; no substance removal was observed. On the TiN-coated abutments, only slight treatment traces, if any, were recorded, and there was no substance removal. A planing effect (ie, an Rz decrease of 66.4%) was observed. The plastic curette and the air scaler caused no damage to the titanium or TiN surfaces. DISCUSSION AND CONCLUSION: The TiN-coated abutments displayed fewer treatment traces, less roughness depth, and less substance removal after being treated with various instruments. Two concerns, however, are the detachment of the coating after only few actions with steel and titanium curettes or with an ultrasonic scaler with steel tip, and the greater initial roughness depth of coated implants.     

Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits

Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone–implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit‐blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large‐grit sand blasting and acid‐etched (SLA). After 2 and 8 weeks of implantation, the bone‐implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina‐Ti, BCP‐Ti and OCP‐Ti groups had similar average surface roughness in the 1–2 μm range whereas the SLA surface was significantly higher with a roughness averaging 4.5 μm. Concerning the osseointegration, the study demonstrated a significantly greater bone‐to‐implant contact for both the SLA and OCP‐Ti surfaces as compared with the grit‐blasted surfaces, alumina‐ and BCP‐Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants.     

Influence of the finishing technique on surface roughness of dental porcelains with different microstructures

This study compared the surface roughness of 4 dental porcelains with different microstructures (d.Sign-D, Finesse-F, Noritake-N and Symbio-S) using varied surface treatments. The porcelain surfaces were submitted to the following surface treatments: 1) g (glazing only); 2) rg (polishing with a rubber wheel before glazing); 3) 2g (reglazing); 4) r (rubber wheels); 5) rp (rubber wheels + diamond paste); 6) d (sandpaper discs) and 7) dp (sandpaper discs + diamond paste). Treatments 3 through 7 were performed after breaking the glaze layer with a diamond bur. Surface roughness (Ra, in m) was determined using a profilometer (n=10). Visual inspection was made using the scanning electron microscope. Microstructural characterization was also performed (hardness, leucite content and particle size). Reglazed specimens presented significantly rougher surfaces compared to glazed specimens. The use of a polishing paste after the sandpaper discs or after the rubber wheel resulted in a reduction of the Ra value for all materials (except for the dp group of porcelain S). Rubber or discs followed by diamond paste were the best surface treatments for porcelains D (D-rp: 0.21 +/- 0.06 microm and D-dp: 0.22 +/- 0.05 microm) and F (F-rp and F-dp: 0.17 +/- 0.03 microm). For porcelains N and S, both reglazing (2g) and the use of rubber or sandpa- per discs followed by diamond paste (groups rp and dp) resulted in similar roughness (N-2g: 0.22 +/- 0.03 microm; N-rp: 0.22 +/- 0.04 microm; N-dp: 0.20 +/- 0.04 microm, S-2g: 0.22 +/- 0.04 microm; S-rp: 0.19 +/- 0.04 microm; S-dp: 0.23 +/- 0.04 microm). CONCLUSION: The best choice of surface treatment for leucite-based porcelains depended on the material considered. Porcelains with lower leucite content (F and S) tended to present lower roughness compared to those with higher leucite content after being polished with rubbers or discs followed by diamond pastes.     

17β-雌二醇对骨质疏松状态下牙种植体骨整合的影响

目的：研究17β-雌二醇（17β-E2）对骨质疏松大鼠种植体-骨界面骨整合指数的影响。方法：6月龄未交配SD雌性大鼠随机分为3组,A：假去势手术组（SHAM）,B：去势手术非药组（OVX）,C：17β-E2治疗组（E2）,每组13只。将后两组行卵巢切除术,并在卵巢切除术后1．5个月对所有大鼠右股骨远中种植纯钛螺钉,E2组在种植术后-周开始给予17β-E2（30μg／kg）治疗。分别于种植术后1．5个月及3个月,随机处死各组动物的-半。处死后,取大鼠右股骨,沿种植体长轴将种植体连同骨组织平均切为两半,扫描电镜观察与测量种植体-骨结合骨接触率即骨整合指数（OI）。结果：1．5个月与3个月处死时,E2组与SHAM组骨整合指数大致相同（E2组略高）,它们明显高于OVX组如〈0．05）。各组大鼠不同时期处死时,骨整合指数大致相同0〉0．05）。结论：1．骨质疏松改变可使大鼠种植体-骨界面骨整合指数降低。2．17β-E2可使骨质疏松大鼠种植体-骨界面骨整合指数增加。3．骨整合完成后,延长时间并不能使骨整合指数增加。     

Optimisation of the hydrogen peroxide pre‐treatment of titanium: surface characterisation and protein adsorption

Background: Researchers have attempted to enhance titanium osseointegration by modifying its surface properties, including via H₂O₂ pre‐treatment, with reported treatment regimes varying from minutes/hours, to weeks. Objective: This study examined the effects of various H₂O₂ treatments on titanium surface topography/roughness, chemical composition/oxide thickness, hydrophilicity and plasma protein adsorption. Materials and methods: Titanium discs were treated with 30% H₂O₂ for 0–24 h or 1–4 weeks and subjected to atomic force microscopy (AFM), scanning electron microscopy (SEM), profilometry, X‐ray photon spectroscopy and contact angle analysis. For protein adsorption, whole plasma and FITC‐conjugated serum albumin were added to 0–24 h and
1–4 week H₂O₂‐treated discs and examined by SEM and fluorescence microscopy, respectively. Results: AFM, SEM and profilometry demonstrated that 1–6 h H₂O₂‐treated discs exhibited subtle alterations in surface topography/roughness at the nanometre scale, although 24 h and 1–4 week H₂O₂‐treated discs exhibited much greater increases in surface roughness, in the micrometre range. Maximal increases in surface oxide thickness and chemical modification were identified between 1 h–4 weeks and 3 h–4 weeks, respectively, although no increases in oxygen/titanium (O1s : Ti2p) molar ratio or in hydrophilicity were evident. Plasma and serum albumin adsorption increased on 1–24 h H₂O₂‐treated discs, with further increases on 1–4 week H₂O₂‐treated discs. Conclusions: Based upon the present data and previous findings, this study supports the concept that surface topography/roughness and oxide composition/thickness, are more significantly modified by H₂O₂ treatment and more influential to protein adsorption than hydrophilicity. Additionally, it can be hypothesized that the 24 h H₂O₂ treatment of titanium surfaces, which induced micrometre scale changes in roughness and protein adsorption, to those associated with enhanced osteoblast attachment/behaviour, mineralisation and subsequent implant osseointegration, would be most beneficial.