Sandblasted And Acid-etched Surfaces Research Articles

Micro/Nanostructured Topography on Titanium Orchestrates Dendritic Cell Adhesion and Activation via β2 Integrin-FAK Signals.

In clinical application of dental implants, the functional state of dendritic cells (DCs) has been suggested to have a close relationship with the implant survival rate or speed of osseointegration. Although microscale surfaces have a stable osteogenesis property, they also incline to trigger unfavorable DCs activation and threaten the osseointegration process. Nanoscale structures have an advantage in regulating cell immune response through orchestrating cell adhesion, indicating the potential of hierarchical micro/nanostructured surface in regulation of DCs' activation without sacrificing the advantage of microscale topography. Two micro/nanostructures were fabricated based on microscale rough surfaces through anodization or alkali treatment, the sand-blasted and acid-etched (SA) surface served as control. The surface characteristics, in vitro and in vivo DC immune reactions and β2 integrin-FAK signal expression were systematically investigated. The DC responses to different surface topographies after FAK inhibition were also tested. Both micro/nano-modified surfaces exhibited unique composite structures, with higher hydrophilicity and lower roughness compared to the SA surface. The DCs showed relatively immature functional states with round morphologies and significantly downregulated β2 integrin-FAK levels on micro/nanostructures. Implant surfaces with micro/nano-topographies also triggered lower levels of DC inflammatory responses than SA surfaces in vivo. The inhibited FAK activation effectively reduced the differences in topography-caused DC activation and narrowed the differences in DC activation among the three groups. Compared to the SA surface with solely micro-scale topography, titanium surfaces with hybrid micro/nano-topographies reduced DC inflammatory response by influencing their adhesion states. This regulatory effect was accompanied by the modulation of β2 integrin-FAK signal expression. The β2 integrin-FAK-mediated adhesion plays a critical role in topography-induced DC activation, which represents a potential target for material-cell interaction regulation.

Comparison of osseointegration of Ti–Al6V4 and Ti–Al6Nb7 implants: An experimental study

ObjectiveIn this study we aimed to investigate bone–implant connections (BICs) with Ti–Al6V4 and Ti–Al6Nb7 alloys. Two types of surface morphology, resorbable blast material (RBM) and sandblasted and acid-etched surfaces (SLA), were used for implants. Materials and methodsThirty female Sprague Dawley rats aged 0.5–1 year were used. The rats were randomly separated into three groups: 1) Ti–Al6V4 RBM surface (n = 10), 2), Ti–Al6Nb7 RBM surface (n = 10), and 3) Ti–Al6Nb7 SLA (n = 10) surface implants were surgically integrated in femoral bones. The average roughness (Ra) values for these implants were 1–2 Ra. The rats were sacrificed four weeks after the surgical procedure. For each section, the BIC ratio (%) was determined as a percentage of the total implant surface that was in direct contact with the bone. ResultsThe BIC ratio was found to be higher in the Ti–Al6Nb7 RBM and Ti–Al6Nb7 SLA groups than in the Ti–Al6V4 RBM group (p < 0.05). There was no statistically significant difference in the BIC ratios between the Ti–Al6Nb7 RBM and Ti–Al6Nb7 SLA groups (p > 0.05). ConclusionTi–Al6Nb7 exhibited good biocompatibility with bone cells. Ti–Al6Nb7 alloy could be a candidate material for dental implant production.

The effect of strontium modified rough titanium surface on biologic response of MC3T3-E1 cells.

It has been shown that strontium (Sr) promotes bone formation, reduces bone resorption. In the study, magnetron sputtering method was used for preparing Sr covered on sandblasted and acid-etched (SLA) titanium surface. Surface morphology was examined by scanning electron microscopy (SEM), chemical composition of surface was investigated by X-ray energy dispersive spectrometry (EDS). MC3T3-E1cells were cultured on Sr-SLA and SLA disks. Cell morphology was studied through confocal laser scanning microscope and SEM. Cell proliferation were measured by MTT assay. Degrees of mineralization and alkaline phosphatase (ALP) activity were calculated and compared. EDS and SEM results indicated that Sr ions were successfully loaded in Sr-SLA surface, whereas, Sr-SLA and SLA surfaces demonstrated similar typical isotropic irregular indentations. The MC3T3-E1 cells developed on Sr-SLA surface showed improved morphology, better proliferation as well as greater differentiation.These findings suggest that the modification with Sr incorporated in moderately rough surface has a favorable biocompatibility.

Surface alterations following instrumentation with a nylon or metal brush evaluated with confocal microscopy

PurposeSurface alterations of titanium discs following instrumentation with either a nylon brush or a metal brush were evaluated.MethodsA total of 27 titanium discs with 3 surface types (9 discs for each type), including machined (M) surfaces, sandblasted and acid-etched (SA) surfaces, and surfaces treated by resorbable blast media (RBM), were used. Three discs were instrumented with a nylon brush, another 3 discs were instrumented with a metal brush, and the remaining 3 discs were used as controls for each surface type. Surface properties including the arithmetic mean value of a linear profile (Ra), maximum height of a linear profile (Rz), skewness of the assessed linear profile (Rsk), arithmetic mean height of a surface (Sa), maximum height of a surface (Sz), developed interfacial area ratio (Sdr), skewness of a surface profile (Ssk), and kurtosis of a surface profile (Sku) were measured using confocal microscopy.ResultsInstrumentation with the nylon brush increased the Ra, Sa, and Sdr of the M surfaces. On the SA surfaces, Ra, Sa and Sdr decreased after nylon brush use. Meanwhile, the roughness of the RBM surface was not affected by the nylon brush. The use of the metal brush also increased the Ra, Sa, and Sdr of the M surface; however, the increase in Sdr was not statistically significant (P=0.119). The decreases in the Rz, Sz, Ra, Sa, and Sdr of the SA surfaces were remarkable. On the RBM surfaces, the use of the metal brush did not cause changes in Ra and Sa, whereas Rz, Sz, and Sdr were reduced.ConclusionsTitanium surfaces were altered when instrumented either with a nylon brush or a metal brush. Hence, it is recommended that nylon or metal brushes be used with caution in order to avoid damaging the implant fixture/abutment surface.

Effect of Plasma Oxidation-Treated TiOx Film on Early Osseointegration.

To develop a TiOx film with high wettability using plasma oxidation methodology and to evaluate the effect of such surface modification on new bone formation and early osseointegration. Twenty sandblasted and acid-etched (SLA) titanium implants layered with a TiOx film layer were modified by plasma oxidation using a Radio Frequency Plasma Enhanced Chemical Vapor Deposition (RFPECVD) system. Twenty SLA implants without any treatment were employed as the control group. Scanning electron microscopy was used to evaluate surface morphology of the coating. X-ray photoelectron spectroscopy (XPS) was utilized to identify the chemical composition of the implant surface, and the wettability was tested with the help of the contact angle calculation. All implants were randomly inserted into the proximal tibia of 20 rats with a split-plot design. Four weeks after implantation, early osseointegration of the two groups was analyzed by a removal torque test and histologic analysis. The surface characteristics showed that both SLA and plasma oxidization-treated SLA (PO-SLA) surfaces displayed similar typical isotropic irregular indentations. As revealed by the XPS analyses, both TiO2 and Ti2O3 were coexistent in the PO-SLA surface. The contact angle measurement revealed that the super-hydrophilic surface was created out in the PO-SLA surface. Four weeks after implantation, a higher removal torque value was observed in the group of implants with the PO-SLA surface compared with the control group (12.68 ± 1.07 vs 9.95 ± 1.42 Ncm, P < .05), and a higher rate of bone-to-implant contact was also detected in the same group of implants with the PO-SLA surface (47.79% ± 9.59% vs 39.41% ± 9.00%, P < .05). The bone area ratio was also higher in the PO-SLA surface group than the control group (39.10% ± 10.01% vs 29.01% ± 7.24%, P < .05). It was indicated that the PO-SLA surface has combined the effect of high wettability and micro/nano-structures to notably increase early bone apposition.

The effect of strontium-loaded rough titanium surface on early osseointegration.

It is not clear whether surface bioactive chemistry plays an important role in the early osseointegration of micro-structured titanium implants that have the same surface topography at the micrometer and submicrometer scales. In this study, magnetron sputtering methodology was employed for the preparation of Sr coating on sandblasted and acid-etched (SLA) titanium implant without changing the surface characteristics. The study of the surface morphology of the coating was carried out with the use of scanning electron microscopy, and the chemical composition of the surface was examined by X-ray energy-dispersive spectrometry. Twenty SLA implants together with 20 Sr-SLA implants were randomly inserted into the proximal tibia of 20 rats. The early osseointegration of the Sr-SLA implant was compared with SLA implant by removal torque test and histological analysis following two and eight weeks of implantation, correspondingly. As revealed by the surface characteristics, both Sr-SLA and SLA surfaces exhibited similar typical isotropic irregular indentations. The strontium ions were effectively incorporated into the SLA surface (the atomic ratio is 2%). Following two and eight weeks of healing, significant increases in removal torque values ( p < 0.05) were taken into observation in respect of Sr-SLA implant. Histologically, the Sr-SLA implants displayed significantly higher bone-to-implant contact percentages and bone area ratio in comparison with the SLA implant at eight weeks ( p < 0.05). At two weeks, the bone-implant contact percentages, together with bone area ratio of Sr-SLA surface appeared to be a little bit slightly greater than that of SLA surface. But the statistical difference was not significant. These results indicated that the chemical modification with Sr incorporated by magnetron sputtering treatment in moderately rough surfaced implants remarkably increases early bone apposition.

The Effects of a Er:YAG Laser on Machined, Sand-Blasted and Acid-Etched, and Resorbable Blast Media Titanium Surfaces Using Confocal Microscopy and Scanning Electron Microscopy

Purpose: Laser treatment has become a popular method in implant dentistry, and lasers have been used for the decontamination of implant surfaces when treating peri-implantitis. This study was performed to evaluate the effects of an Erbium-doped:Yttrium-Aluminum-Garnet (Er:YAG) laser with different settings on machined (MA), sand-blasted and acid-etched (SA), and resorbable blast media (RBM) titanium surfaces using scanning electron microscopy and confocal microscopy. Materials and Methods: Four MA, four SA, and four RBM discs were either irradiated at 40 mJ/20 Hz, 90 mJ/20 Hz, or 40 mJ/25 Hz for 2 minutes. The specimens were evaluated with scanning electron microscopy and confocal microscopy. Result: The untreated MA surface demonstrated uniform roughness with circumferential machining marks, and depressions were observed after laser treatment. The untreated SA surface demonstrated a rough surface with sharp spikes and deep pits, and the laser produced noticeable changes on the SA titanium surfaces with melting and fusion. The untreated RBM surface demonstrated a rough surface with irregular indentation, and treatment with the laser produced changes on the RBM titanium surfaces. The Er:YAG laser produced significant changes on the roughness parameters, including arithmetic mean height of the surface (Sa) and maximum height of the surface (Sz), of the MA and SA surfaces. However, the Er:YAG laser did not produce notable changes on the roughness parameters, such as Sa and Sz, of the RBM surfaces. Conclusion: This study evaluated the effects of an Er:YAG laser on MA, SA, and RBM titanium discs using confocal microscopy and scanning electron microscopy. Treatment with the laser produced significant changes in the roughness of MA and SA surfaces, but the roughness parameters of the RBM discs were not significantly changed. Further research is needed to evaluate the efficiency of the Er:YAG laser in removing the contaminants, adhering bacteria, and the effects of treatment on cellular attachment, proliferation, and differentiation.

Enhanced Hydrophilicity and Protein Adsorption of Titanium Surface by Sodium Bicarbonate Solution

The aim of this study was to investigate a novel and convenient method of chemical treatment to modify the hydrophilicity of titanium surfaces. Sand‐blasted and acid‐etched (SLA) titanium surfaces and machined titanium surfaces were treated with sodium bicarbonate (NaHCO3) solution. The wetting behavior of both kinds of surfaces was measured by water contact angle (WCA) test. The surface microstructure was assessed with scanning electron microscopy (SEM) and three‐dimensional (3D) optical microscopy. The elemental compositions of the surfaces were analyzed by X‐ray photoelectron spectroscopy (XPS). The protein adsorption analysis was performed with fibronectin. Results showed that, after 1 M NaHCO3 treatment, the hydrophilicity of both SLA and machined surfaces was enhanced. No significant microstructural change presented on titanium surfaces after NaHCO3 treatment. The deprotonation and ion exchange activities might cause the enhanced hydrophilicity of titanium surfaces. The increased protein adsorption of NaHCO3‐treated SLA surfaces might indicate their improved tissue‐integration in clinical use.

Ag-plasma modification enhances bone apposition around titanium dental implants: an animal study in Labrador dogs.

Dental implants with proper antibacterial ability as well as ideal osseointegration are being actively pursued. The antimicrobial ability of titanium implants can be significantly enhanced via modification with silver nanoparticles (Ag NPs). However, the high mobility of Ag NPs results in their potential cytotoxicity. The silver plasma immersion ion-implantation (Ag-PIII) technique may remedy the defect. Accordingly, Ag-PIII technique was employed in this study in an attempt to reduce the mobility of Ag NPs and enhance osseointegration of sandblasted and acid-etched (SLA) dental implants. Briefly, 48 dental implants, divided equally into one control and three test groups (further treated by Ag-PIII technique with three different implantation parameters), were inserted in the mandibles of six Labrador dogs. Scanning electron microscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma optical emission spectrometry were used to investigate the surface topography, chemical states, and silver release of SLA- and Ag-PIII-treated titanium dental implants. The implant stability quotient examination, Microcomputed tomography evaluation, histological observations, and histomorphometric analysis were performed to assess the osseointegration effect in vivo. The results demonstrated that normal soft tissue healing around dental implants was observed in all the groups, whereas the implant stability quotient values in Ag-PIII groups were higher than that in the SLA group. In addition, all the Ag-PIII groups, compared to the SLA-group, exhibited enhanced new bone formation, bone mineral density, and trabecular pattern. With regard to osteogenic indicators, the implants treated with Ag-PIII for 30 minutes and 60 minutes, with the diameter of the Ag NPs ranging from 5–25 nm, were better than those treated with Ag-PIII for 90 minutes, with the Ag NPs diameter out of that range. These results suggest that Ag-PIII technique can reduce the mobility of Ag NPs and enhance the osseointegration of SLA surfaces and have the potential for future use.

The influence of ultraviolet irradiation on sandblasted and acid-etching surface adsorbing human fibronectin

To study the influence of ultraviolet (UV) irradiation on physical and chemical properties of sandblasted and acid-etched (SA) titanium surface and their ability to adsorb human fibronectin (HFn). SA and UV-SA surfaces were separately prepared. Surface morphology, roughness, elemental composition, wettability and HFn adsorption assay were performed for comparative analysis of these two surfaces. SA and UV-SA surface had a similar morphology with multi-holes, and average roughness. UV-SA surface had a lower C content (22.83%) and higher O content (51.20%) and presented hydrophilicity, while SA surface showed hydrophobicity. But the quantity of adsorbed HFn on SA surface at 10 min assay point [(0.41 ± 0.07) µg] was statistically higher than that on UV-SA surface [(0.26 ± 0.08) µg](P = 0.007). UV irradiation would not change the morphology and roughness of SA surface. However, it could reduce the hydrocarbon and increase the hydroxyl groups, and the absorption of HFn on UV-SA surface at 10 min assay point was statistically lower than that on SA surface. Therefore, the in-vitro bioactivity of UV-SA surface was not as good as that of SA surface.

Effects of titanium brush on machined and sand‐blasted/acid‐etched titanium disc using confocal microscopy and contact profilometry

Mechanical techniques, including scaling with metal, plastic, or ultrasonic instruments, rubber cup polishing, air-powder abrasive system and brushing with a conventional or a rotating brush, have been used for the debridement of dental implants. Recently, rotating brushes with titanium bristles (titanium brush) have been introduced for the debridement of implant surface when peri-implant osseous defects occur. The purpose of this study was to evaluate the effects of a titanium brush on machined (MA) and sand-blasted and acid-etched (SA) titanium surfaces using scanning electron microscopy, confocal microscopy and profilometry. Moreover, correlations between the two quantitative evaluation methods (confocal microscopy and contact profilometry) were assessed. Both MA and SA discs were treated with rotating titanium brush at 300 rpm under irrigation for a total of 40 s. Roughness measurements were taken with confocal microscopy and surface profilometry. Then, the MA and SA surfaces were evaluated using scanning electron microscopy to determine the changes of the surface properties. Untreated MA surface demonstrated uniform roughness with circumferential machining marks, and scratch lines over the original surfaces were observed after treatment with the titanium brush. Similarly, the titanium brush produced noticeable changes on the SA titanium surfaces. However, this treatment with titanium brush did not significantly change the roughness parameters, including the arithmetic mean height of the surface (Sa) and the maximum height of the surface (Sz), in both MA and SA surfaces. Correlations between two evaluation methods showed a Pearson correlation coefficient of 0.98 with linear regression R(2) of 0.96. This study showed that the treatment with the titanium brush did not significantly change the roughness parameters, including Sa and Sz, in both MA and SA surfaces. Correlations between confocal microscopy and surface profilometry showed high correlation with a Pearson correlation coefficient of 0.98.

The effects of mechanical instruments on contaminated titanium dental implant surfaces: a systematic review

The objective of this systematic review was to evaluate the ability of mechanical instruments to clean contaminated implant titanium surfaces. MEDLINE, Cochrane-CENTRAL and EMBASE databases were searched up to May 2013 to identify controlled studies on the cleaning efficacy of mechanical instruments on contaminated titanium surfaces. A comprehensive search identified 1893 unique potential papers. Fourteen studies met the inclusion criteria and were selected for this systematic review. Most of the studies were in vitro studies. Different surfaces and different contamination methods were used. Most studies used titanium discs, strips and cylinders. The air abrasive was the treatment mostly evaluated. The available studies had a high heterogeneity that precluded any statistical analysis of the data. Therefore, the conclusions are not based on quantitative data. Non-metal curettes and rubber cups were found to be ineffective. Positive results were reported for (ultra)sonic scalers with a metal tip on polished surfaces, (ultra)sonic scalers with a non-metal tip on smooth and sand-blasted and acid-etched (SLA) surfaces, metal curettes and rotating titanium brushes on SLA surfaces. The air abrasive was found to be effective in cleaning machined, SLA and titanium plasma-sprayed (TPS) surfaces. The available data suggest that the air abrasive may remove plaque effectively from machined, SLA and TPS titanium surfaces. Positive results were also observed for rotating titanium brushes on SLA surfaces and ultrasonic scalers with non-metal tip on polished and SLA surfaces. However, the clinical impact of these findings requires further clarification.

The effect of surface treatment of titanium with sand-blasting/acid-etching or hydroxyapatite-coating and application of bone morphogenetic protein-2 on attachment, proliferation, and differentiation of stem cells derived from buccal fat pad

This study was performed to evaluate the effect of surface treatment of titanium, including: machined (MA), sand-blasted and acid-etched (SA), and hydroxyapatite-coated (HA) surfaces, and application of bone morphogenetic protein-2 (BMP-2) on attachment, proliferation, and differentiation of stem derived from buccal fat pad. Stem cells were isolated from buccal fat pad. Stem cells were cultured on MA, SA, and HA titanium discs with and without BMP-2. Cellular attachment and alkaline phosphatase (ALP) activity were evaluated at day 3, 7, and 14. Osteocalcin expression was performed using immunofluorescent assay. The cells grown on MA surface demonstrated good attachment with spindle-like morphology, and cells grown on SA and HA surfaces demonstrated more stellate-like morphology. An increase of ALP activity was seen in the rough surface (SA and HA groups) and a statistically significant increase was seen in the HA group (p < 0.05). The addition of BMP-2 made an expression of osteocalcin, and the highest expression of osteocalcin was noted in the HA group. Within the limits of this study, surface modification of titanium surfaces by sand-blasting/acid-etching or hydroxyapatite-coating was not able to allow the stem cells to differentiate into osteoblasts without exogenous soluble factors. The addition of BMP-2 showed osteogenic differentiation of stem cells and HA-coated surfaces demonstrated the highest ALP and osteocalcin expression.

An in vitro evaluation of the responses of human osteoblast-like SaOs-2 cells to SLA titanium surfaces irradiated by erbium:yttrium–aluminum–garnet (Er:YAG) lasers

Erbium:yttrium-aluminum-garnet (Er:YAG) laser treatment is an effective option for the removal of bacterial plaques. Many studies have shown that Er:YAG lasers cannot re-establish the biocompatibility of titanium surfaces. The aim of this study was to evaluate the responses of the human osteoblast-like cell line, SaOs-2, to sand-blasted and acid-etched (SLA) titanium surface irradiation using different energy settings of an Er:YAG laser by examining cell viability and morphology. Forty SLA titanium disks were irradiated with an Er:YAG laser at a pulse energy of either 60 or 100 mJ with a pulse frequency of 10 Hz under water irrigation and placed in a 24-well plate. Human osteoblast-like SaOs-2 cells were seeded onto the disks in culture media. Cells were then kept in an incubator with 5% carbon dioxide at 37 °C. Each experimental group was divided into two smaller groups to evaluate cell morphology by scanning electron microscope and cell viability using 3-4,5-dimethylthiazol 2,5-diphenyltetrazolium bromide test. In both the 60 and the 100 mJ experimental groups, spreading morphologies, with numerous cytoplasmic extensions, were observed prominently. Similarly, a majority of cells in the control group exhibited spreading morphologies with abundant cytoplasmic extensions. There were no significant differences among the laser and control groups. The highest cell viability rate was observed in the 100 mJ laser group. No significant differences were observed between the cell viability rates of the two experimental groups (p = 1.00). In contrast, the control group was characterized by a significantly lower cell viability rate (p < 0.001). Treatments with an Er:YAG laser at a pulse energy of either 60 or 100 mJ do not reduce the biocompatibility of SLA titanium surfaces. In fact, modifying SLA surfaces with Er:YAG lasers improved the biocompatibility of these surfaces.

Literature Reviews

Literature Reviews

Modified titanium surfaces promote accelerated osteogenic differentiation of mesenchymal stromal cells in vitro

Titanium (Ti) is the material of choice for dental and orthopaedic implants due to its highly biocompatible nature. Modification of the implant surface, either topographically (as roughness) or chemically, can promote accelerated osteogenesis in vivo and greatly increase bone-implant contact and bonding strength. In this paper, we sought to characterise the cellular and molecular responses of human bone marrow-derived mesenchymal stromal cells (hMSCs) to two modified Ti surfaces: a rough hydrophobic surface that was sand-blasted and acid-etched (SLA) and an SLA surface of the same roughness that was chemically modified to have high wettability/hydrophilicity (SLActive). A smooth polished (SMO) Ti surface was used as a control. Whilst no differences in initial cell attachment to any of the surfaces were observed, we found that hMSCs cultured on the rough surfaces underwent a decrease in cell number early in culture, yet simultaneously expressed higher levels of the osteogenic markers SPP1, RUNX2 and BSP. Furthermore, deposits of calcified matrix were observed at earlier time points on both SLA and SLActive surfaces compared to SMO and this correlated with increased expression of the osteogenic promoter WNT5A in response to the rough surfaces. Osteogenic responses to SLActive were moderately better than the hydrophobic SLA surface and gene expression studies indicate that WNT5A activation may be responsible for this increased osteogenic differentiation.

Bone apposition around two different sandblasted and acid‐etched titanium implant surfaces: a histomorphometric study in canine mandibles

The aim of this study was to evaluate bone apposition to a modified sandblasted and acid-etched (SLA) implant surface (modSLA) in the canine mandible as compared with the standard SLA surface. In this experimental study, all mandibular premolars and first molars were extracted bilaterally in five foxhounds. After a healing period of 6 months, each side of the mandible received six randomly assigned dental implants alternating between the standard SLA and modSLA surface. The dogs were sacrificed at 2 weeks (n=2) or 4 weeks (n=3) after implant placement. Histologic and histomorphometric analyses were then performed for each implant. The microscopic healing patterns at weeks 2 and 4 for the two implant types with the standard SLA and modSLA surfaces showed similar qualitative findings. New bone tissue had already established direct contact with implant surfaces after 2 weeks of healing. The mean percentage of newly formed bone in contact with the implant (BIC) was significantly greater for modSLA (28.2+/-7.9%) than for SLA (22.2+/-7.3%) (P<0.05). This difference was no longer evident after 4 weeks. An increase in BIC for both implant surface types occurred from weeks 2 to 4. This increase was statistically significant when compared with SLA at 2 weeks (P<0.05), but not when compared with modSLA at 2 weeks. The data from the present study demonstrate significantly more bone apposition for the modSLA surface than the standard SLA surface after 2 weeks of healing. This increased bone apposition may allow a further reduction of the healing period following implant placement for patients undergoing early loading procedures.

Interface shear strength of titanium implants with a sandblasted and acid-etched surface: a biomechanical study in the maxilla of miniature pigs.

The purpose of the present study was to evaluate the interface shear strength of unloaded titanium implants with a sandblasted and acid-etched (SLA) surface in the maxilla of miniature pigs. The two best documented surfaces in implant dentistry, the machined and the titanium plasma-sprayed (TPS) surfaces served as controls. After 4, 8, and 12 weeks of healing, removal torque testing was performed to evaluate the interface shear strength of each implant type. The results revealed statistically significant differences between the machined and the two rough titanium surfaces (p <.00001). The machined surface demonstrated mean removal torque values (RTV) between 0.13 and 0.26 Nm, whereas the RTV of the two rough surfaces ranged between 1.14 and 1.56 Nm. At 4 weeks of healing, the SLA implants yielded a higher mean RTV than the TPS implants (1.39 vs. 1. 14 Nm) without reaching statistical significance. At 8 and 12 weeks of healing, the two rough surfaces showed similar mean RTVs. The implant position also had a significant influence on removal torques for each implant type primarily owing to differences in density in the periimplant bone structure. It can be concluded that the interface shear strength of titanium implants is significantly influenced by their surface characteristics, since the machined titanium surface demonstrated significantly lower RTV in the maxilla of miniature pigs compared with the TPS and SLA surfaces.