Biomechanical evaluation of a titanium implant surface conditioned by a hydroxide ion solution

Two groups of titanium dental implants, identical in geometry but different in the treatment of their surfaces, were tested in an in vivo minipig model of the mandible. The surfaces that were tested were, first, sandblasted and acid-etched; and secondly, sandblasted, acid-etched, and conditioned. The removal torque was assessed at 2, 4, and 8 weeks after implantation (n=6 animals in each healing period). The interfacial stiffness was also evaluated. All dental implants were well-integrated at the time of death. Removal torque values increased significantly over the course of 8 weeks. Removal torque and interfacial stiffness were increased for conditioned surfaces after 2 weeks, but there were no significant differences between the two surfaces. The sandblasted and acid-etched implants are the standard, and conditioning of the surface showed a tendency to increase early peri-implant formation of bone.     

Optimum surface properties of oxidized implants for reinforcement of osseointegration: surface chemistry, oxide thickness, porosity, roughness, and crystal structure

PURPOSE: To investigate detailed surface characterization of oxidized implants in a newly invented electrolyte system and to determine optimal surface oxide properties to enhance the bone response in rabbits. MATERIALS AND METHODS: A total of 100 screw-type titanium implants were prepared and divided into 1 control group (machine-turned implants) and 4 test groups (magnesium ion-incorporated oxidized implants). Forty implants were used for surface analyses. A total of 60 implants, 12 implants from each group, were placed in the tibiae of 10 New Zealand white rabbits and measured with a removal torque test after a healing period of 6 weeks. RESULTS: For the test groups, the oxide thicknesses ranged from about 1,000 to 5,800 nm; for the control group, mean oxide thickness was about 17 nm. The surface morphology showed porous structures for test groups and nonporous barrier film for the control group. Pore diameter ranged from < or = 0.5 microm to < or = 3.0 microm. In regard to surface roughness, arithmetic average height deviation (Sa) values varied from 0.68 to 0.98 microm for test implants and 0.55 microm for control implants; developed surface ratio (Sdr) values ranged from 10.6% to 46% for the test groups and were about 10.6% for the control group. A mixture of anatase and rutile-type crystals were observed in the test groups; amorphous-type crystals were observed in the control group. After a healing period of 6 weeks, removal torque measurements in all 4 test groups demonstrated significantly greater implant integration as compared to machine-turned control implants (P < or = .033). DISCUSSION: Determinant oxide properties of oxidized implants are discussed in association with bone responses. Of all surface properties, RTVs were linearly increased as relative atomic concentrations of magnesium ion increase. CONCLUSIONS: Surface properties of the oxidized implants in the present study, especially surface chemistry, influenced bone responses. The surface chemistry of the optimal oxidized implant should be composed of approximately 9% magnesium at relative atomic concentration in titanium oxide matrix and have an oxide thickness of approximately 1,000 to 5,000 nm, a porosity of about 24%, and a surface roughness of about 0.8 microm in Sa and 27% to 46% in Sdr; its oxide crystal structure should be a mixture of anatase- and rutile-phase crystals.     

Histomorphometric evaluation of six dental implant surfaces after early loading in augmented human sinuses

This study investigated the bone-to-implant contact (BIC) and osteoconductive capacity (OC) of 6 different implant surfaces after early loading in humans. Two implants with different surfaces were placed side-by-side in the grafted (n= 5) and nongrafted (n = 1) sinuses of 3 volunteers. Single-tooth restorations were delivered 60 days later. After 6 months of full occlusal loading, implants were retrieved in block sections for histomorphometric analysis. One implant (acid etched) placed in grafted bone failed when loaded. There were no other complications. In grafted bone, the microtextured surface achieved the highest BIC value (94.08%), followed by the oxidized (77.32%), hydroxyapatite (HA) (74.51%), sandblasted and acid-etched (51.85%), and titanium plasma-sprayed (TPS) (41.48%) surfaces. In native bone, the acid-etched surface achieved a higher BIC value (69.03%) than the HA surface (59.03%). The highest OC value in grafted bone was exhibited by the microtextured surface (34.31%), followed by the HA (28.62%), sandblasted and acid-etched (25.08%), oxidized (17.55%), and TPS (-20.47%) surfaces. The HA surface exhibited a higher OC value (30.39%) in native bone compared with the acid-etched surface (24.0%). As a whole, highest BIC and OC values were exhibited by the microtextured surface, and lowest values were exhibited by the TPS surface. All other surfaces demonstrated excellent BIC (>50%) but varied in OC (range = 17.55%-28.62%). These findings are tempered by the limited scope and sample size of the study and should be considered preliminary. More research is needed to determine the impact of implant surface texture on BIC and OC.     

Increased bone formation around coated implants

Aim: We hypothesized that coating threaded, sandblasted acid-etched titanium implants with collagen and chondroitin sulphate (CS) increases bone formation and implant stability, compared with uncoated controls.
Materials and Methods: Three different implant surface conditions were applied: (1) sandblasted acid-etched (control), (2) collagen/chondroitin sulphate (low-dose – CS1), (3) collagen/chondroitin sulphate (high-dose – CS2). Sixty 9.5 mm experimental implants were placed in the mandible of 20 minipigs. Bone–implant contact (BIC) and relative peri-implant bone-volume density (rBVD – relation to bone-volume density of the host bone) were assessed after 1 and 2 months of submerged healing. Implant stability was measured by resonance frequency analysis (RFA).
Results: After 1 month, coated implants had significantly more BIC compared with controls (CS1: 68%, p <0.0001, CS2: 63%, p =0.009, control: 52%). The rBVD was lower for all surface conditions, compared with the hostbone. After 2 months, BIC increased for all surfaces. No significant differences were measured (CS1: 71%, p =0.016, CS2: 68%, p =0.67, control: 63%). The rBVD was increased for coated implants. RFA values were 71–77 at implantation, 67–73 after 1 month and 74–75 after 2 months. Differences in rBVD and RFA were not statistically significant.
Conclusions: Data analysis suggests that collagen/CS has a positive influence on bone formation after 1 month of endosseous healing.     

Effect of plasma-sprayed hydroxyapatite coating on the osteoconductivity of commercially pure titanium implants

Formation of a calcium phosphate layer was studied on the surfaces of plasma-sprayed hydroxyapatite (PSHA) and sandblasted commercially pure (cp) titanium in simulated body fluid with ion concentrations similar to those of human blood plasma. The PSHA surface induced the formation of calcium phosphate surface layers, while the precipitation of calcium phosphate on sandblasted cp titanium was not detected. Histologic evaluation of in vivo tests demonstrated that implants with a PSHA coating enabled the growth of bone tissue into gaps with a depth of up to 1 mm without significant formation of intermediate fibrous tissue. In comparison to sandblasted cp titanium, implants with PSHA coating exhibited greater tolerance to unfavorable conditions during healing, such as gaps at the interface or primary instability of the implant. In the case of good primary stability of the implant, filling of the gap with fibrous tissue was observed for sandblasted cp titanium implants over the greater part of the surface of gaps with a depth of 0.3 mm. Direct contact of cp titanium implants with bone was achieved only when the press-fit implantation model was used.     

Early bone response to sandblasted,dual acid-etched and H2O2/HCl treated titanium implants: an experimental study in the rabbit

The aim of this study was to evaluate the influence of a roughened H₂O₂/HCl heat-treated titanium surface on peri-implant bone formation at an early stage in vivo. 24 Ti₆Al₄V alloy implants were used; half were treated by sandblasted and dual acid-etched treatments (control group), while the others were treated by sandblasted, dual acid-etched and H₂O₂/HCl heat treatments (test group). The morphology and roughness were analyzed by field emission SEM and atomic force microscopy. The implants were inserted into the femora of 12 adult white rabbits. After 2 and 4 weeks, femora block specimens were prepared for histological and histomorphometric analysis. SEM micrographs showed that multilevel and different sized pits were formed on both surfaces. New bone formation was observed on both implant surfaces. Test implants demonstrated a greater mean percentage of bone-implant contact as compared with controls at 2 (46.84 vs. 41.81, p=0.000) and 4 weeks (49.43 vs. 44.87, p=0.006) of healing. It is concluded that the H₂O₂/HCl heat-treated rough titanium surface promoted enhanced bone apposition during the early stages of new bone formation around the implant.     

Surface analysis of machined versus sandblasted and acid-etched titanium implants

Initially, implant surface analyses were performed on 10 machined implants and on 10 sandblasted and acid-etched implants. Subsequently, sandblasted and acid-etched implant cytotoxicity (using L929 mouse fibroblasts), morphologic differences between cells (osteoblast-like cells MG63) adhering to the machined implant surfaces, and cell anchorage to sandblasted and acid-etched implant surfaces were evaluated. Results indicated that acid etching with 1% hydrofluoric acid/30% nitric acid after sandblasting eliminated residual alumina particles. The average roughness (Ra) of sandblasted and acid-etched surfaces was about 2.15 microns. Cytotoxicity tests showed that sandblasted and acid-etched implants had non-cytotoxic cellular effects and appeared to be biocompatible. Scanning electron microscopic examination showed that the surface roughness produced by sandblasting and acid etching could affect cell adhesion mechanisms. Osteoblast-like cells adhering to the machined implants presented a very flat configuration, while the same cells adhering to the sandblasted and acid-etched surfaces showed an irregular morphology and many pseudopodi. These morphologic irregularities could improve initial cell anchorage, providing better osseointegration for sandblasted and acid-etched implants.     

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.     

Histomorphometric analysis of implant anchorage for 3 types of dental implants following 6 months of healing in baboon jaws

In an effort to better understand the supporting anatomy for unloaded endosseous dental implants, this study focused on the histomorphometric analysis of 3 different types of implants placed into non-human primate jaws and allowed to heal for 6 months. This report describes data from 24 screw-type dental implants placed in edentulated (2 months healing time) posterior arches of 4 adult female baboons. Three different implants were placed and allowed to heal for 6 months prior to processing for evaluation: commercially pure titanium (n = 8), titanium alloy (n = 8), and titanium plasma-sprayed (n = 8). Circumferential bone-implant interface sampling from 6 regions along the entire length of each implant was obtained for evaluation of percent bone-implant contact (%BIC) and percent bone area (%BA), within 3 mm of the implant. Data were collected (reliability of 1.6% for both parameters) and analyzed by an observer blinded to implant material using IMAGE analysis software for differences between jaws, implant biomaterials, and jaw/biomaterial (analysis of variance, pairwise comparison using least squares method with Bonferroni adjustment). The results indicated that the overall mean %BIC was 55.8 and mean %BA was 48.1. Maxillary and mandibular differences for both parameters were statistically significantly different: %BIC in maxilla 50.8, in mandible 60.8; %BA in maxilla 43.6, in mandible 52.6 (both significant at the P < .05 level). The biomaterial analyses revealed no significant differences between the different implants for %BIC or %BA. The trend observed--that mandibular values were greater than maxillary values for the overall jaw comparisons--was found to be consistent at the jaw/biomaterial level, although the small sample size limited statistical power. These data, along with data from a previous 3-month study, provide insight into baseline supporting anatomy for 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.     

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.     

Histomorphometric study of ion implantation and diamond-like carbon as dental implant surface treatments in beagle dogs

PURPOSE: Improvements in the bone-implant interface can provide clinical benefits, such as increasing the amount of bone in contact with the implant and shortening the time required to achieve sufficient bone appositioning to allow early prosthetic loading. The present study describes the results obtained with 2 new surface treatments: (a) CO ion implantation; and (b) diamond-like carbon (DLC) coating. MATERIALS AND METHODS: Each group (ion implantation, DLC, and the control group, turned titanium) consisted of 12 samples. Beagle dogs subjected to previous partial edentulation were used. Dual histologic evaluation was made of percentage bone-implant contact (% BIC) of all samples based on conventional histomorphometric analysis and environmental scanning electron microscopy (ESEM). RESULTS: The results obtained after 3 and 6 months of dental implant placement showed greater and faster bone integration in the CO ion implantation group (61% and 62% BIC, respectively) compared with the DLC group (47% and 50%); the data corresponding to the ion implanted samples were statistically significant compared with the control group (33% and 49% BIC after 3 and 6 months, respectively). CONCLUSIONS: The results showed improved % BIC for implants with ion-implanted surfaces in comparison to DLC coating and machined controls. Furthermore, bone integration appeared to be accelerated in the ion implantation group, since high % BIC values were recorded in the early stages after in vivo implantation.     

Surface characterization of SLActive dental implants

The aim of the study was to characterize the surface chemistry, hydration capacity, topography and roughness of the root part of a hydrophilic sandblasted and acid-etched titanium dental implant (SLActive). Implants as received (SAR), after water rinsing (SAW) and after ultrasonication in water (SAU) were subjected to x-ray photoelectron spectroscopy (XPS) elemental and binding state analysis. Scanning electron microscopy plus energy dispersive x-ray microanalysis (SEM/EDX), reflection Fourier transform infrared microspectroscopy (RFTIRM) and hydration/ dehydration cycling by environmental scanning electron microscopy (ESEM), were performed in SAR, whereas SAU implants were subjected to 3D-optical profilometry and SEM. For all the experiments, a conventional sandblasted and acid-etched implant (SLA ) of the same manufacturer was used as control. XPS showed lower mean C content in SAR than SLA, but not significantly different. In SAW, the C and O contents were increased. Significantly reduced C and increased Ti and O contents were found in SAU. Residual Na phases, other than NaCl, were traced in all SLActive groups. SAR demonstrated higher [-OH]/O2- ratio than SLA . EDX documented higher O, Na, Cl and lower Ti content in SAR. More -OH contributions were probed on SAR in comparison with SLA by RFTI RM. Ti-O peaks assigned to anatase, rutile and amorphous phases were found in both implant groups. The ESEM study revealed a full rehydration capacity in SAR, in contrast to SLA. No differences were found in the topography of SAU and SLA implant surfaces under the SEM. However, significantly greater values in spatial and functional roughness parameters were encountered in SAU. The increased surface hydroxylated titanium content and the greater spatial and functional roughness parameters, may explain the enhanced biological activity documented for SLActive in comparison with SLA.     

Enhanced bone apposition to a chemically modified SLA titanium surface

Increased surface roughness of dental implants has demonstrated greater bone apposition; however, the effect of modifying surface chemistry remains unknown. In the present study, we evaluated bone apposition to a modified sandblasted/acid-etched (modSLA) titanium surface, as compared with a standard SLA surface, during early stages of bone regeneration. Experimental implants were placed in miniature pigs, creating 2 circular bone defects. Test and control implants had the same topography, but differed in surface chemistry. We created the test surface by submerging the implant in an isotonic NaCl solution following acid-etching to avoid contamination with molecules from the atmosphere. Test implants demonstrated a significantly greater mean percentage of bone-implant contact as compared with controls at 2 (49.30 vs. 29.42%; p = 0.017) and 4 wks (81.91 vs. 66.57%; p = 0.011) of healing. At 8 wks, similar results were observed. It is concluded that the modSLA surface promoted enhanced bone apposition during early stages of bone regeneration.     

Comparison of chemically and pharmaceutically modified titanium and zirconia implant surfaces in dentistry: a study in sheep

Advanced surface modifications and materials were tested on the same implant geometry. Six types of dental implants were tested for osseointegration after 2, 4 and 8 weeks in a sheep pelvis model. Four titanium implant types were treated with newly developed surface modifications, of which two were chemically and two were pharmacologically modified. One implant was made of zirconia. A sandblasted and acid-etched titanium surface was used as reference. The chemically modified implants were plasma-anodized or coated with calcium phosphate. The pharmacological coatings contained either bisphosphonate or collagen type I with chondroitin sulphate. The implants were evaluated using macroscopic, radiographic and histomorphometric methods. All implants were well osseointegrated at the time of death. All titanium implants had similar bone implant contact (BIC) at 2 weeks (57-61%); only zirconia was better (77%). The main BIC increase was between 2 and 4 weeks. The pharmacologically coated implants (78-79%) and the calcium phosphate coating (83%) showed similar results compared with the reference implant (80%) at 8 weeks. There were no significant differences in BIC. Compared with previous studies the results of all implants were comparatively good.     

Performance of double acid-etched surface external hex titanium implants in relation to one- and two-stage surgical procedures

BACKGROUND: The use of external hex titanium implants is widely accepted; however, in the past few years, they have been placed by using not only the traditional two-stage surgical protocol, but also the one-stage surgical protocol. The aim of the present study was to compare the success rates that can be obtained from two-stage surgeries (conventional protocol) and one-stage surgeries when double acid-etched surface external hex titanium implants are used. METHODS: A total of 654 double acid-etched surface external hex titanium implants were studied in 195 patients (109 females and 86 males) aged 18 to 79 (mean 49.20). These patients were followed-up both clinically and radiographically for 3 years. Among these implants, 338 were inserted by means of two-stage surgery and 316 were placed following the one-stage surgery protocol. RESULTS: The success rate of the whole sample of double acid-etched surface implants was 99.23%. The results showed a 99.05% success rate for one-stage surgeries and 99.40% rate for two-stage surgeries. Only three of the implants inserted by performing one-stage surgery and two of the implants placed using two-stage surgery failed before they were loaded. No implants were lost after the loading was completed. The bone level at 12 months was 0.58 mm for one-stage-placed implants and 0.54 mm for two-stage-placed implants. At 24 months the bone level was 0.77 mm and 0.68, respectively, and at 36 months 0.89 and 0.83. CONCLUSION: The similar and high success rates obtained in one- and two-stage surgeries using double acid-etched surface external hex titanium implants demonstrate that it is possible to choose the most convenient surgical procedure for each particular case without increasing the risk of failure.     

纯钛阳极氧化伴水热处理后羟基磷灰石薄涂层种植体的实验研究

目的：了解阳极氧化伴水热处理后纯钛种植的体内成骨效应。方法：36枚纯钛种植体采用4种表面处理,随机植入12只兔股骨内,分别在术后4周、8周、16周取出带种植体骨块制作磨片,观察界面新生骨情况以及抛光、水热处理种植体术后8周的界面超微结构,行表面能谱分析。结果：术后8周,阳极氧化伴水热处理种植体表面编码骨的转化和成熟较快,至16周时界面几乎无编织骨和剥脱的羟基磷灰石碎片,种植体表面的钙,磷含量在种植后增加,抛光种植体表面钙、磷含量增加不明显。结论：纯钛经阳极氧化伴水热处理后,可以加快种植表现编织骨转化为板层骨,从而可能促进种植区的早期愈合,薄涂层特有的优越性尚待进一步研究。     

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.     

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.