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.     

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.     

Analysis of failed commercially pure titanium dental implants: a scanning electron microscopy and energy-dispersive spectrometer x-ray study

BACKGROUND: The failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure. METHODS: Twenty-one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 +/- 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant. RESULTS: SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium. CONCLUSION: These preliminary results do not suggest any material-related cause for implant failures, although different element composition was assessed between failed implants and control implants.     

Surface chemistry effects of topographic modification of titanium dental implant surfaces: 2. In vitro experiments

PURPOSE: To determine, in vitro, cytotoxicity and cell adhesion on 3 different implant surfaces. MATERIALS AND METHODS: All samples had machined surfaces, but they were subjected to different cleaning procedures, which produced 3 different surface chemistries. One of the samples was "as-produced" from the machining tools. The other samples were subjected to partial and total cleaning routines. Cytotoxicity was evaluated using mouse fibroblast cultures, and cell adhesion was evaluated with osteoblast-like SaOS-2 cells. RESULTS: The "as-produced" sample showed a pronounced surface contamination by lubricating oils. For partially and totally cleaned samples, an increasing amount of titanium and a decreasing carbon/titanium ratio was observed as cleaning became more complete. DISCUSSION: Differences in surface chemistry such as those normally found on titanium implant surfaces (see part 1 of this series) can lead to those same effects which, in in vitro experiments, are normally accounted for in terms of surface topography alone. CONCLUSION: Effects related to surface chemistry can operate over and above surface topography, making it impossible, without proper characterization, to make definite statements about the role of topography alone.     

Physico-chemical characterization of the surface of 9 dental implants with 3 different surface treatments

There are many surface treatments applied to dental implants. The aim of the present investigation is to compare the physicochemical characteristics of titanium dental implant surfaces with different surface treatments. 9 dental implants from the same batch were divided in 3 groups and received 3 different surface treatments: machined, acid etched and a new chemical surface treatment called Avantblast. Scanning electron microscopy and confocal microscopy were used to image the treated surfaces, and energy-dispersive spectrometry and X-ray photoelectron spectrometry to provide a chemical characterization of the surfaces. RESULTS: The acid etched and chemical etched surfaces had an increased roughness over the machined one. Surface chemical composition had differences between processes, as the surface with the new treatment presented a reduced level of impurities and increased thickness of the titanium oxide layer. CONCLUSIONS: Surface roughness of titanium dental implants and thickness of the titanium oxide layer can be increased with a suitable surface treatment.     

Radiographic evaluation of dental implants with different surface treatments: an experimental study in dogs

PURPOSE: The aim of the study was to radiographically measure the bone density at the peri-implant region after osseointegration and to compare the relative bone density achieved by different surface-treated implants. MATERIALS AND METHODS: Four different types of implant surfaces were compared, using five young-adult male mongrel dogs. The first, second, third, and fourth lower premolars were extracted. Ninety days after removal, four 3.75-mm diameter and 10-mm long screw implants (Paragon) were placed with different surface treatments in the lower hemiarches. The dogs received two implants each of the following surface treatments: 1) smooth (machined); 2) titanium plasma spray: 3) hydroxyapatite coating; and 4) sandblasting with soluble particles. The implants were maintained unloaded for 90 days. After this period, the animals were killed and the hemimandibles were extracted and radiographed. The grey level of the bone adjacent to implants was measured with a specific software tool (line histogram) and the relative bone density was calculated. RESULTS: The four different surface treatments promote different numeric levels of bone density around the dental implants (sandblasting with soluble particles, 52.45 +/- 2.95; titanium plasma spray, 53.98 +/- 3.67; machined, 55.78 +/- 3.06, and hydroxyapatite coating, 58.2 +/- 2.71). Therefore, the implants can be ranked in terms of relative bone density from high to low as follows: sandblasting with soluble particles, titanium plasma spray, machined, and hydroxyapatite coating. There were no statistically significant differences in bone density among the four groups (P = 0.1130, analysis of variance). CONCLUSION: Surface treatments that add roughness to the implant show numerically higher bone density when compared with machined surfaces. The findings of radiographic density analysis suggest that the soluble blasting media-treated surface provides a greater bone density at the peri-implant region.     

Biomechanical and histological behavior of zirconia implants: an experiment in the rat

Objective: This study aimed at evaluating the integration of zirconia implants in a rat femur model.
Material and methods: Zirconia implants with two distinct surface topographies were compared with titanium implants with similar topographies. Titanium and zirconia implants were placed into the femurs of 42 male Sprague–Dawley rats. Four groups of implants were utilized: machined zirconia implants, zirconia implants with a rough surface, machined titanium implants, and titanium implants with an electrochemically roughened surface. After a healing period of 28 days, the load-bearing capacity between the bone and the implant surface was evaluated by a push-in test. Additionally, after a healing period of 14 and 28 days, respectively, bone tissue specimens containing the implants were processed and histologically analyzed.
Results: The mean mineralized bone-to-implant contact showed the highest values after 14 and 28 days for the rough surfaces (titanium: 36%/45%; zirconia: 45%/59%). Also, the push-in test showed higher values for the textured implant surfaces, with no statistical significance between titanium (34 N) and zirconia (45.8 N).
Conclusions: Within the limits of the animal investigation presented, it was concluded that all tested zirconia and titanium implant surfaces were biocompatible and osseoconductive. The presented surface modification of zirconia implants showed no difference regarding the histological and biomechanical results compared with an established electrochemically modified titanium implant surface.     

The mucosal attachment to titanium implants with different surface characteristics: an experimental study in dogs

BACKGROUND: Findings from in vitro studies have indicated that the orientation and proliferation of cells on titanium surfaces may be influenced by the topography of the surface on which they are grown. It may be argued, therefore, that differences may occur in the mucosal attachment to titanium implants with different surface roughness. AIM: The present experiment was performed to study the composition of the soft tissue barrier that formed to implants prepared with well-defined smooth or rough surfaces. MATERIAL AND METHODS: Five beagle dogs were used. Four implants made of c.p. titanium were placed in the right edentulous mandibular premolar region. After 3 months, two different types of abutments were connected: one experimental (OA) with a dual, thermal acid-etched surface ('Osseotite'), and one regular (RA) abutment with a 'turned' surface. At the end of a 6-month period during which proper plaque control had been maintained, biopsies including the implant and the surrounding soft and hard tissues were obtained, decalcified and processed for light and electron microscopy. A confocal He-Ne laser profilometer was used to study the surface topography of the abutments. RESULTS: The attachment between the peri-implant mucosa and titanium abutments with either a turned (RA; 'smooth') or acid-etched (OA; 'rough') surface was similar from both a quantitative and a qualitative aspect. The attachment comprised a barrier epithelium and a zone of connective tissue attachment of similar dimension at RA and OA. It was further observed that the 'inner' zone of the connective tissue attachment at both types of abutment was composed of about 30-33% fibroblasts and 63-66% collagen. CONCLUSION: It was demonstrated that the soft tissue attachment that formed to implants made of c.p. titanium was not influenced by the roughness of the titanium surface.     

Effect of chemically modified titanium surfaces on protein adsorption and osteoblast precursor cell behavior

PURPOSE: To investigate the effects of different chemically modified titanium surfaces on protein adsorption and the osteoblastic differentiation of human embryonic palatal mesenchymal (HEPM) cells. MATERIALS AND METHODS: Three different surfaces were evaluated. The first, a machined surface (Ti-M), was considered a control. The second surface was acid etched (Ti-AE). The third surface was prepared by exposing the Ti-AE samples to sodium hydroxide (NaOH) solution (Ti-AAE). The surface characteristics of chemically modified titanium were investigated by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and profilometry. To evaluate the production of biomarkers, commercial kits were utilized. RESULTS: Surface composition and morphology affected the kinetics of protein adsorption. Ti-AE surfaces manifested a greater affinity for fibronectin adsorption compared to Ti-M or Ti-AAE surfaces. It was observed that Ti-AE and Ti-AAE surfaces promoted significantly greater cell attachment compared to Ti-M surfaces. Statistically significant differences were also observed in the expression of alkaline phosphatase (ALP) activity, osteocalcin, and osteopontin on all 3 titanium surfaces. ALP activity and osteocalcin production up to day 12 suggested that differentiation of the cells into osteoblasts had occurred and that cells were expressing a bone-forming phenotype. CONCLUSIONS: It was thus concluded from this study that surface morphology and composition play a critical role in enhancing HEPM cell proliferation and differentiation into osteoblast cells.     

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.     

Acute inflammatory response to laser-induced micro- and nano-sized titanium surface features

Background: The inflammatory process induced by implant surfaces is an important component of the tissue response, where limited knowledge is available regarding the role of surface topography. With laser ablation, a combined micro‐ and nanoscale surfacemodification could be created, which have been shown to enhance bone growth and biomechanical stability in vivo. Purpose: The aim of this article was to evaluate the early in vivo inflammatory response to laser‐modified titanium disks, with machined titanium disks and sham operation sites serving as controls. Materials and Methods: Circular disks were installed in a subcutaneous rat model for 24 and 72 hours, where the cell number, cell types, and cytokine levels were evaluated. Results: The results revealed that significantly fewer inflammatory cells (mononuclear and polymorphonuclear) were attracted to the sites with the laser‐modified implants compared with the machined titanium implants. Similar concentrations of pro‐inflammatory cytokines (TNF‐a and MCP‐1), together with slightly higher cell viability, were observed around the laser‐modified surface compared with the machined surface. Conclusions: The results in the present study suggest that the combination of surface micro and nano features of the laser‐treated surface contributes to the downregulation of early inflammatory events.     

Surface treatment of dental implants with high-energy laser beam]

In the present study the biological value of the laser prepared titanium implants has been investigated. Screw-type implants with different surface modifications were placed into the femurs of rabbits. Removal torque measurements and histological examinations were prepared. The examinations were divided into two groups. In the first part of the examinations the laser surface treatment was compared to other type of surface modifications. In the examination groups the implants were prepared with the following surfaces: 1. machined, 2. sandblasted, 3. low intensity laser surface, 4. high intensity laser surface, 5. titanium oxide coated surface. In the second part of the examinations laser treatment with different physical variables were observed. It has been concluded, that in both cases the high energy laser treated implants needed higher removal torque and in some cases an osteogenic activity was observed around them in the medullary space as well. The authors think the advantage of laser surface treatment lies in special micromorphology and the increased cleanliness of the surface.     

Histological comparison of bone to implant contact in two types of dental implant surfaces: a single case study

AIM: The purpose of this single case study was to evaluate the influence of different implant surfaces on human bone and osseointegration. METHODS AND MATERIALS: A 47-year-old partially edentulous woman received two experimental implants along with conventional implant therapy. Experimental implants placed in the mandibular ramus consisted of machined and anodized surfaces, respectively. After three months of healing, the experimental implants were removed and prepared for ground sectioning and histological analysis. RESULTS: The data demonstrate anodized implant surfaces present a higher percentage of osseointegration when compared to a machined surface in cortical human bone after a healing period of three months. CONCLUSION: This single case study suggests an anodized implant surface results in a higher percentage of bone to implant contact when compared to machined surfaced implants when placed in dense bone tissue. However, further investigations should be conducted.     

Adsorption of human plasma proteins to modified titanium surfaces

OBJECTIVES: The aim of this study was to examine the effect of modified titanium (Ti) surfaces on the initial events of plasma proteins adsorption. MATERIALS AND METHODS: 'Ti disks' with three types of surface modifications were compared: machined, acid-etched and acid-etched and blasted. Physical and chemical characterizations of the surfaces were performed via scanning electron microscopy (SEM), atomic force microscopy (AFM) used for analysis of surface topography, characterization of the titanium oxide (TiO2) layer was carried out by X-ray photoelectron spectroscopy (XPS) and characterization of surface energy by the determination of contact angles. Evaluation of plasma proteins' adsorption to the treated Ti surfaces was performed by mass spectrometry, confocal laser scanning microscopy and XPS. Quantitative proteins' assessment was carried out by enzyme-linked immunosorbent assay. RESULTS: SEM images revealed major differences in the topography of the examined surfaces. Acid-etched and blasted Ti surfaces were found to have higher roughness values and a thicker TiO2 layer as compared with acid-etched and machined surfaces. Moreover, acid-etched and blasted surfaces showed high surface area differentiation, pointing to a high increase in the three-dimensional (3D) surface area over the 2D surface area compared with the other surfaces. Adsorption of plasma proteins to the acid-etched and blasted Ti surfaces was both qualitatively and quantitatively more intense compared with the machined and acid-etched surfaces. This was shown for each examined protein, total proteins and by the removal degree of the protein coat. CONCLUSIONS: The preferential adsorption of plasma proteins to the acid-etched and blasted Ti surfaces may be explained by its topographical characteristics and by the increase of the 3D surface area of this modified surface.     

Biomimetic calcium phosphate composite coating of dental implants

PURPOSE: The aim of the present study was to test the hypothesis that calcium phosphate coating of titanium screw-type implants enhances peri-implant bone formation in the jaw. MATERIALS AND METHODS: Ten adult female foxhounds received experimental titanium screw-type implants in the mandible 3 months after removal of all premolar teeth. Four types of implants were evaluated in each animal: implants with machined titanium surface (the control group), implants coated with collagen I (the collagen-only group), implants with a composite coating of calcium phosphate and mineralized collagen I (the composite group), and implants with calcium phosphate (hydroxyapatite [HA]) coating (the HA-only group). Peri-implant bone regeneration was assessed histomorphometrically after 1 and 3 months in 5 dogs each by measuring bone-implant contact (BIC) and the volume density of the newly formed peri-implant bone (BVD). RESULTS: After 1 month, BIC was significantly enhanced only in the group of implants with composite coating of calcium phosphate and mineralized collagen (P = .038). Volume density of the newly formed peri-implant bone was significantly higher in all coated implants after 1 month. No significant difference from baseline was found in BIC for the collagen-only and HA-only groups, but BVD was significantly higher in implants with composite coating (P = .041). After 3 months, BIC and BVD were significantly higher in all coated implants than in the controls with machined surfaces. CONCLUSION: It was concluded that composite coating of dental screw-type implant surfaces using calcium phosphate and collagen can enhance BIC and peri-implant bone formation.     

The effect of titanium topography features on mesenchymal human stromal cells' adhesion

Objective: The aim of this study was to evaluate the effect of two kinds of dental implants surfaces with their own characteristics on human marrow stromal cells' adhesion. Material and methods: Fifty‐six titanium discs (28 machined and 28 acid etched) were used. Machined (MS) and acid‐etched surfaces (ES) were analyzed using a scanning electron microscope, energy dispersing spectroscopy (EDS), contact angle analysis and human marrow stromal cells' culture. Results: Significant differences were observed in the topography and wetability of the tested surfaces. However, etched surfaces presented a high level of wetability when compared with machined surfaces. Contact angles showed considerable differences between etched and machined surfaces (Friedman test P<0.05). EDS analysis showed the same composition on both the surfaces tested. Counting of adhered cells on both types of surfaces showed that there is no statistical significance in human marrow stromal cells' adhesion after 18 h (Mann–Whitney test P>0.05). Conclusion: The present study concludes that modifications on the titanium implant surfaces roughness may promote differences in the morphology of bone marrow stromal cells. Nevertheless, in this microenvironment, no interference in the adhesion phenomenon was noted. To cite this article:
Carneiro‐Campos LE, Fernandes CP. The effect of titanium topography features on mesenchymal human stromal cells' adhesion.
Clin. Oral Impl. Res. 21 , 2010; 250–254.
doi: 10.1111/j.1600‐0501.2009.01811.x     

A histomorphometric analysis of the effects of various surface treatment methods on osseointegration

PURPOSE: One major factor in the success and biocompatibility of an implant is its surface properties. The purposes of this study were to analyze the surface characteristics of implants after blasting and thermal oxidation and to evaluate the bone response around these implants with histomorphometric analysis. MATERIALS AND METHODS: Threaded implants (3.75 mm in diameter, 8.0 mm in length) were manufactured by machining a commercially pure titanium (grade 2). A total of 48 implants were evaluated with histomorphometric methods and included in the statistical analyses. Two different groups of samples were prepared according to the following procedures: Group 1 samples were blasted with 50-microm aluminum oxide (Al2O3) particles, and group 2 samples were blasted with 50-microm Al2O3, then thermally oxidized at 800 degrees C for 2 hours in a pure oxygen atmosphere. A noncontacting optical profilometer was used to measure the surface topography. The surface composition of the implants used and the oxide thickness were investigated with Rutherford backscattering spectrometry. RESULTS: The different preparations produced implant surfaces with essentially similar chemical composition, but with different oxide thickness and roughness. The morphologic evaluation of the bone formation revealed that: (1) the percentage of bone-to-implant contact of the oxidized implants (33.3%) after 4 weeks was greater than that of the blasted group (23.1%); (2) the percentages of bone-to-implant contact after 12 weeks were not statistically significantly different between the groups; (3) the percentages of bone area inside the thread after 4 weeks and 12 weeks were not statistically significantly different between groups. DISCUSSION AND CONCLUSION: This investigation demonstrated the possibility that different surface treatments, such as blasting and oxidation, have an effect on the ingrowth of bone into the thread. However, the clinical implications of surface treatments on implants, and the exact mechanisms by which the surface properties of the implant affect the process of osseointegration, remain subjects for further study.     

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.     

Histomorphometric analysis of the bone-implant contact obtained with 4 different implant surface treatments placed side by side in the dog mandible

PURPOSE: The different implant systems available today present several types of surface treatment, with the aim of optimization of bone-implant contact. This study compared 4 different types of implant surfaces. MATERIALS AND METHODS: The first, second, third, and fourth mandibular premolars were extracted from 5 young adult mongrel male dogs. Ninety days after removal, four 3.75-mm-diameter, 10-mm-long screw-type implants (Paragon) were placed with different surface treatments in mandibular hemiarches. The dogs received 2 implants of each of the following surface treatments: smooth (machined), titanium plasma spray (TPS), hydroxyapatite coating (HA), and sandblasting with soluble particles (SBM). The implants were maintained unloaded for 90 days. After this period, the animals were sacrificed, and the hemimandibles were extracted and histologically processed to obtain non-decalcified sections. Two longitudinal ground sections were made for each implant and analyzed under light microscopy coupled to a computerized system for histomorphometry. RESULTS: The following means were obtained for bone-implant contact percentage: machined = 41.7%, TPS = 48.9%, HA = 57.9%, and SBM = 68.5%. DISCUSSION: The means for all treatments that added roughness to the implant surface were numerically superior to the mean found for the machined surface. However, this difference was statistically significant only between groups SBM and machined (Tukey test, P < .05). CONCLUSIONS: The SBM-treated surface provided a greater bone-implant contact than a machined surface after 90 days without loading in this model.     

Formation of mineralizing osteoblast cultures on machined, titanium oxide grit-blasted, and plasma-sprayed titanium surfaces

Altering osseous responses at implant surfaces to enhance bone is a current goal of clinical therapy. Cell culture may be used to investigate surface-dependent responses of bone-forming cells. In this report, the ability of primary fetal bovine mandibular osteoblast cultures to form a mineralizing matrix on machined, titanium plasma-sprayed, and titanium oxide grit-blasted surfaces has been compared. Immunohistochemical markers associated with bone formation were used to define the differentiated state of the formed matrix using qualitative light microscopy, and von Kossa staining was used to demonstrate the presence of mineralization within this matrix. Compared to either titanium oxide grit-blasted or machined surfaces, titanium plasma-sprayed surfaces displayed a unique pattern of mineralized matrix formation. Scanning electron microscopy further revealed that each surface accumulated unique organic and inorganic deposits during matrix formation, suggesting that surface-dependent physicochemical and biochemical conditioning of implant surfaces takes place. Surface topographic features of commercially pure titanium substrates can alter cultured osteoblast extracellular matrix formation and mineralization. Similar molecular and cellular assessment of in vivo responses to implant surface topography may contribute to improved engineering of endosseous implants.