Sand-blasted Acid-etched Surface Research Articles

Enhanced osteogenic differentiation of mesenchymal stem cells by surface lithium modification in a sandblasted/acid-etched titanium implant.

This study investigated the osteogenesis-related cell functions of osteoprogenitor cells modulated by surface chemistry modification using lithium (Li) ions in a current clinical oral implant surface in order to gain insights into the future development of titanium (Ti) implants with enhanced osteogenic capacity. Wet chemical treatment was performed to modify a sandblasted/acid-etched (SLA) Ti implant surface using Li ions. The osteogenesis-related cell response to the surface Li ion-modified SLA sample was evaluated using two kinds of murine bone marrow stem cells, bipotent ST2 cells and primary multipotent mesenchymal stem cells (MSCs). The modified surface exhibited the formation of an Li-containing Ti oxide layer with plate-like nanostructures. The Li-incorporated surface enhanced early cellular events, including spreading, focal adhesion formation and integrin mRNA expression (α2, α5, αv and β3), and accelerated osteogenic differentiation of bipotent ST2 cells compared with unmodified SLA surface. Surface Li modification significantly increased GSK-3β phosphorylation and suppressed β-catenin phosphorylation, and promoted the subsequent osteogenic differentiation of primary MSCs. These results indicate that surface chemistry modification of SLA implants by wet chemical treatment with Li ions induces a more favorable osseointegration outcome through the promotion of the osteogenic differentiation of bone marrow MSCs via the positive regulation of GSK-3β and β-catenin activity.

Osteogenic Differentiation of Human Mesenchymal Stem Cells Modulated by Surface Manganese Chemistry in SLA Titanium Implants.

The manganese (Mn) ion has recently been probed as a potential candidate element for the surface chemistry modification of titanium (Ti) implants in order to develop a more osteogenic surface with the expectation of taking advantage of its strong binding affinity to the integrins on bone-forming cells. However, the exact mechanism of how Mn enhances osteogenesis when introduced into the surface of Ti implants is not clearly understood. This study investigated the corrosion resistance and potential osteogenic capacity of a Mn-incorporated Ti surface as determined by electrochemical measurement and examining the behaviors of human mesenchymal stem cells (MSCs) in a clinically available sandblasted/acid-etched (SLA) oral implant surface intended for future biomedical applications. The surface that resulted from wet chemical treatment exhibited the formation of a Mn-containing nanostructured TiO2 anatase thin film in the SLA implant and improved corrosion resistance. The Mn-incorporated SLA surface displayed sustained Mn ion release and enhanced osteogenesis-related MSC function, which enhanced early cellular events such as spreading, focal adhesion, and mRNA expression of critical adhesion-related genes and promoted full human MSC differentiation into mature osteoblasts. Our findings indicate that surface Mn modification by wet chemical treatment is an effective approach to produce a Ti implant surface with increased osteogenic capacity through the promotion of the osteogenic differentiation of MSCs. The improved corrosion resistance of the resultant surface is yet another important benefit of being able to provide favorable osseointegration interface stability with an increased barrier effect.

Experimental implantoplasty outcomes correlate with fibroblast growth in vitro

BackgroundImplantoplasty is an option in peri-implantitis treatment, but little is known about the effect on the soft tissue. The aim of the study was to characterize surface roughness following experimental implantoplasty and to examine its effect on human fibroblast growth and secretion of selected proteins.MethodsTitanium grade IV coins were mechanically treated with six different rotating bur sequences; diamond burs or carbide burs alone, or followed by either Arkansas stone bur or silicone burs. Machined and rough-surface sandblasted, acid-etched (SLA) coins were used as control. The surface topography was characterized by scanning electron microscope and profilometer. Human gingival fibroblasts from two donors were cultured on the coins to quantify the effect on cell morphology, growth, and protein secretion by confocal microscopy and multiplex immunoassay.ResultsAll surface roughness parameters were lower for the surfaces treated with experimental implantoplasty than for the SLA surface, and the sequence of carbide burs followed by silicone burs rendered the least rough surface of the test groups. The implantoplasty procedures changed the elemental composition of the titanium surface. High surface roughness showed a weak to moderate negative correlation to fibroblast growth, but induced a higher secretion of VEGF, IL-6 and MCP-3 to the cell medium compared to the least rough surfaces of the test groups. At day 30 fibronectin levels were higher in the SLA group.ConclusionsThe surface roughness following implantoplasty demonstrated a weak to moderate negative correlation with the growth of fibroblasts. The addition of Arkansas stone and silicon burs to the experimental implantoplasty bur protocol rendered an initial increase in fibroblast growth. Implantoplasty altered the elemental composition of the titanium surface, and had an effect on the fibroblast cytokine secretion and fibronectin levels.

In vivo studies of titanium implant surface treatment by sandblasted, acid-etched and further anchored with ceramic of tetracalcium phosphate on osseointegration

The objective was to investigate and compare the osseointegrative responses of sandblasted/acid-etched (SLA) and calcium phosphate (CaP) implants in vivo. The CaP implant was prepared by control group of SLA surface modification and anchoring with sintering ceramic of tetracalcium phosphate (TTCP) to form a mechanical interlocking film. Customized screw Ti implants (size O 2.0 mm × 6 mm length) were utilized to histologically examine the bone-to-implant contact (BIC) after implantation. The implant stability quotient scales in the postoperative implants within femurs were recorded. Subsequently, the postoperative implants were scanned using microcomputed tomography (micro-CT), and the topography was examined microscopically to analyze the BIC conditions. The SLA and CaP implant groups showed increased bone mineral density (g/cm3) and BIC (%). Compared with the SLA implant, the CaP implant with TTCP improved the early osteointegration of the BIC at 1-month post-operation and demonstrated quantitative effects on the BIC at 1-month post-operation. SLA and CaP implants all showed good osseointegration through micro-CT analysis (1–6 months). The current findings suggest the CaP anchoring Ti surface demonstrated improvement in early stages of osseointegration and thus shows the potential clinical benefits of TTCP anchoring on Ti surfaces in bone-level solutions.

Multifunctional effects of a modification of SLA titanium implant surface with strontium‐containing nanostructures on immunoinflammatory and osteogenic cell function

This study investigated the effects of surface modification of clinically available sandblasted/acid-etched (SLA) titanium oral implants with strontium (Sr)-containing nanostructures on both early immunoinflammatory macrophage cell functions and osteogenic stem cell functions. The goal was to provide insight for future surface engineering of titanium implants with multifunctional effects, that is, tissue healing capacity at both the nonosteogenic cell centered initial stage and the subsequent osteogenic cell-governed later stage-osseointegration process. The Sr-containing nanostructure was prepared in on the SLA-type implant surface by wet chemical treatment. The results showed that Sr modification is favorable for early macrophage cell functions and increases osteogenic capacity of the SLA surface. Surface Sr modification notably upregulated regenerative macrophage phenotype expression and anti-inflammatory cytokine IL10 production while suppressing inflammatory cytokine TNFα. Sr incorporation enhanced certain early cellular events of ST2 stem cells such as early cellular spreading and critical integrin gene expression, which in turn notably increased osteogenic differentiation (osteogenesis-related phenotype gene expression and osteocalcin production) when combined with the microstructured SLA implant surface. Surface modification of SLA-type implants with Sr-containing nanostructures demonstrated the ability to favorably influence early immunoinflammatory macrophage cell functions and the functionality of osteogenesis cells, resulting in an enhanced osseointegration outcome. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3009-3020, 2018.

Comparison of early osseointegration between laser-treated/acid-etched and sandblasted/acid-etched titanium implant surfaces.

This study was designed to compare the early osseointegration of titanium surfaces prepared via laser-treated/acid-etched (LA) and sandblasted/acid-etched (SLA) in dogs. Titanium implants were divided into two groups: Surfaces of the experimental group were treated via LA, while in the control group, surfaces were treated via SLA. The physical and chemical properties of LA and SLA surfaces were tested and compared. Sixteen implants with LA or SLA surfaces were placed into the tibias of four beagle dogs, each treatment group received two implants per single tibia. The dogs were sacrificed two and four weeks after implant placement. Scanning electron microscopy showed that both the LA and SLAs surface exhibited rough structures with micro pores sized 1-3 μm. In the LA surface, regular melting points were observed. However, in the SLA surface, the structure was irregular and few oxide aluminum particles still remained. Only titanium and a small amount of titanium compounds were detected on LA surfaces, while Al was found of SLA surfaces. The LA surface roughness was above that of SLA surfaces (LA: Ra: 2.1 μm; SLA: Ra :1.53 μm; P < 0.01). Both groups exhibited good osseointegration and no significant differences were found in the BIC% at two or four weeks between both groups (P > 0.05). Both groups exhibited good osseointegration; however, the LA surface was cleaner and more uniform than the SLA surface, and no significant differences were found between both groups.

Influence on proliferation and adhesion of human gingival fibroblasts from different titanium surface decontamination treatments: An in vitro study

ObjectivesTo investigate the effects of different decontamination treatments on microstructure of titanium (Ti) surface as well as proliferation and adhesion of human gingival fibroblasts (HGFs). Material and methodsTi discs with machined (M) and sand blasted, acid etched (SAE) surfaces were treated with five different decontamination treatments: (1) stainless steel curette (SSC), ultrasonic system with (2) straight carbon fiber tip (UCF) or (3) metal tip (UM), (4) rotating Ti brush (RTB), and (5) Er:YAG laser (30 mJ/pulse at 30 Hz). Surface roughness was analyzed under optical interferometry. HGFs were cultured on each disc. Proliferation and adhesive strength were analyzed. qRT-PCR and ELISA were performed to detect the RNA and protein expression of FAK, ITGB1, COL1A1, and FN1 respectively from different Ti surfaces. ResultsSurface roughness increased on M surface. Proliferation, adhesive strength and gene expression were higher on M surface than SAE surface. Decontamination treatments affected surface parameters significantly (P < 0.001), making M surface less smooth while SAE surface became less rough. SSC, UCF, UM and RTB decreased proliferation on M surfaces significantly (P < 0.05). UCF, RTB and laser increased proliferation on SAE surface significantly (P < 0.05). UM decreased adhesive strength on M surface significantly and laser increased adhesive strength on SAE surface significantly (P < 0.05). Gene expression increased with time and was altered by decontamination treatments significantly (P < 0.001). ConclusionsDecontamination treatments influence surface roughness and cell behavior of HGFs. Laser might be an optimal decontamination treatment which has the least negative effect on M surface and the most positive effect on SAE surface.

Resonance frequency analysis of dental implants placed at the posterior maxilla varying the surface treatment only: A randomized clinical trial.

BackgroundChemical modifications of the dental implant surface that improve the wettability result in a faster and better osseointegration.PurposeThe aim of this randomized clinical trial was to evaluate the implant stability quotient (ISQ) of implants with similar designs, treated with 2 surfaces, sandblasted acid‐etched (SAE) and hydrophilic SAE, within the initial 16 weeks of healing.Material and methodsA total of 64 implants (32 SAE—control group and 32 modified SAE—test group) with the same design, length, and diameter (conical and compressive, 4.3 × 10 mm) were inserted into the posterior maxillae of 21 patients partially edentulous. The ISQ values were collected at post‐surgery (T0), 1 week (T1), 2 weeks (T2), 3 weeks (T3), 5 weeks (T4), 8 weeks (T5), 12 weeks (T6), and 16 weeks (T7).ResultsNone of the implants failed. Test group presented ISQ values higher than the control group (ANOVA—P < .01) from T5 to T7. When comparing groups regarding the amount of time required to achieve ISQ ≥ 70 as a reference, there was a statistically significant difference (cox regression—P < .01), and a hazard ratio of 2.24 (CI 1.62‐3.11). At the 1‐year follow‐up, there was a drop out of 1 patient, and 2 implants were no longer evaluated. Survival rate for both groups was 100% at the 1‐year follow‐up.ConclusionsThe current study suggests that implants with hydrophilic surface (modified SAE) integrate faster than implants with SAE surface. The stability gain of the test group was 2.24 times faster than the control group after 5 weeks of evaluation at the posterior region of the edentulous maxillae.

Effect of Different Titanium Surfaces on Maturation of Murine Bone Marrow-Derived Dendritic Cells

Dendritic cells (DCs) play a pivotal role in the host response to implanted biomaterials. Osseointegration of titanium (Ti) implant is an immunological and inflammatory-driven process. However, the role of DCs in this complex process is largely unknown. This study aimed to investigate the effect of different Ti surfaces on DC maturation, and evaluate its subsequent potential on osteogenic differentiation of preosteoblasts. Murine bone marrow-derived DCs were seeded on Ti disks with different surface treatments, including pretreatment (PT), sandblasted/acid-etched (SLA) and modified SLA (modSLA) surface. Compared with DCs cultured on PT and SLA surfaces, the cells seeded on modSLA surface demonstrated a more round morphology with lower expression of CD86 and MHC-II, the DC maturation markers. Those cells also secreted high levels of anti-inflammatory cytokine IL-10 and TGF-β. Notably, addition of conditioned medium (CM) from modSLA-induced DCs significantly increased the mRNA expression of Runx2 and ALP as well as ALP activity by murine preosteoblast MC3T3-E1 cells. Our data demonstrated that Ti disks with different surfaces lead to differential DCs responses. PT and SLA surfaces induce DCs mature, while DCs seeded on modSLA-Ti surface maintain an immature phenotype and exhibit a potential of promoting osteogenic differentiation of MC3T3-E1 cells.

Polyspecies biofilm formation on implant surfaces with different surface characteristics

Objective:To investigate the microbial adherence and colonization of a polyspecies biofilm on 7 differently processed titanium surfaces.Material and Methods:Six-species biofilms were formed anaerobically on 5-mm-diameter sterilized, saliva-preconditioned titanium discs. Material surfaces used were either machined, stained, acid-etched or sandblasted/acid-etched (SLA). Samples of the latter two materials were also provided in a chemically modified form, with increased wettability characteristics. Surface roughness and contact angles of all materials were determined. The discs were then incubated anaerobically for up to 16.5 h. Initial microbial adherence was evaluated after 20 min incubation and further colonization after 2, 4, 8, and 16.5 h using non-selective and selective culture techniques. Results at different time points were compared using ANOVA and Scheffé post hoc analysis.Results:The mean differences in microorganisms colonizing after the first 20 min were in a very narrow range (4.5 to 4.8 log CFU). At up to 16.5 h, the modified SLA surface exhibited the highest values for colonization (6.9±0.2 log CFU, p<0.05) but increasing growth was observed on all test surfaces over time. Discrepancies among bacterial strains on the differently crafted titanium surfaces were very similar to those described for total log CFU. F. nucleatum was below the detection limit on all surfaces after 4 h.Conclusion:Within the limitations of this in vitro study, surface roughness had a moderate influence on biofilm formation, while wettability did not seem to influence biofilm formation under the experimental conditions described. The modified SLA surface showed the highest trend for bacterial colonization.

Effects of Ultrasonic Scaler Tips and Toothbrush on Titanium Disc Surfaces Evaluated With Confocal Microscopy

Instrumentation to remove plaque from dental implants may cause damage to the implant surface, and previous studies that have evaluated the effects of the ultrasonic scalers and brushing in experimental settings reported that substantial changes were seen on implant surfaces after mechanical plaque removal. There is limited information on changes of the surface profile and roughness of sandblasted acid-etched (SLA) and machined titanium surfaces after treatment with different instruments in simulated clinical situations. The purpose of this study was to evaluate the effects of oral hygiene instruments including various types of ultrasonic tips in simulated clinical settings and brushing with dentifrice on machined and SLA titanium surface with confocal microscopy. Both SLA and machined discs were treated with various ultrasonic scaler tips and brushing. Discs were either instrumented with 4 different ultrasonic scaler tips or brushed with dentifrice. The entire top surface of the discs was instrumented for a total of 40 seconds (20 seconds, 2 cycles). Brushing with dentifrice was done for 40 seconds. Roughness measurements were performed using a confocal microscope. The change of surface structure after different treatment modalities could be observed with the naked eye when compared with the untreated surface (SLA and machined groups). In case of SLA surfaces, the 2 metal tips produced greater changes on the titanium surfaces when compared with the plastic ultrasonic tips and brushing. On the machined discs, scratch lines over the original surfaces could be observed from all ultrasonic metal and plastic tips, but 2 metal tips produced significant and definite scratches on the original disc surfaces. This study showed the effects of different types of ultrasonic tips and brushing with dentifrice on both SLA and machined titanium surfaces in simulated clinical setting. Within the limits of our study, we suggest that metal or plastic ultrasonic scaler tips may be applied as usual to treat the SLA surface of dental abutment or fixture surfaces without increasing the irregularities on the titanium surfaces. However, in case of machined surfaces, ultrasonic metal tips cannot be recommended because the surface becomes rougher after treatment. In addition, brushing of titanium, regardless of surface treatment (SLA and machined surfaces), resulted in reduction of surface roughness. Meticulous oral hygiene with brushing must be reinforced for the patients with dental implants to maintain the exposed implant surface clean. Brushing with dentifrice may facilitate maintaining the exposed fixture surface clean by smoothening the surface.

Rehabilitation of irradiated patients with modified and conventional sandblasted acid-etched implants: preliminary results of a split-mouth study

The aim of this study was to evaluate the success rate of chemically modified and conventional sandblasted acid-etched surface (SLA) titanium implants in irradiated oral squamous cell carcinoma patients. Twenty patients with a mean age of 61.1 years were treated with dental implants after ablative surgery and radio-chemotherapy of oral cancer. All patients were non-smokers. The placement of SLA and modSLA implants was performed bilaterally according to a split-mouth design. All 102 implants (50 SLA, 52 modSLA) placed showed an unloaded healing time of 6 weeks in the mandible and 10 weeks in the maxilla. Mean crestal bone changes using standardized orthopantomographies and clinical parameters like pocket depths, mPII and mBI were evaluated. Of 102 implants, 55 implants (27 SLA implants, 28 modSLA) were located in the maxilla and 47 implants (23 SLA, 24 modSLA) in the mandible. The average observation period was 14.4 months. The amount of bone loss at the implant shoulder of SLA implants was 0.4 mm mesial and 0.4 mm distal. The modSLA implants displayed a bone loss of mesial 0.3 mm and distal 0.3 mm. Two SLA implants were lost resulting in a success rate of 96%. The success rate of modSLA implants was 100%. Regarding the data found in this investigation, we can conclude that implants with chemically modified and conventional SLA titanium surface show high success rates in irradiated patients. SLA implants with or without a chemically modified surface regardless of the location can be restored with a high predictability of success at least in the short time range observed.

The influence of surface microroughness and hydrophilicity of titanium on the up-regulation of TGFβ/BMP signalling in osteoblasts.

The topography of titanium implants has been identified as an important factor affecting the osseointegration of surgically placed dental implants. Further modification to produce a hydrophilic microrough titanium implant surface has been shown to increase osseointegration compared with microrough topology alone. This study aimed to determine possible molecular mechanisms to explain this clinical observation by examining differences in the whole genome mRNA expression profile of primary human osteoblasts in response to sand-blasted acid-etched (SLA) and hydrophilic SLA (modSLA) titanium surfaces. A decrease in osteoblast proliferation associated with the titanium surfaces (modSLA > SLA > control) correlated with an increase in expression of the osteogenic differentiation markers BSPII and osteocalcin. Pathway analysis demonstrated that a number of genes associated with the TGFβ‑BMP signalling cascade (BMP2, BMP6, SP1, CREBBP, RBL2, TBS3, ACVR1 and ZFYVE16) were significantly differentially up-regulated with culture on the modSLA surface. BMP2 was shown to have the largest fold change increase in expression which was subsequently confirmed at the protein level by ELISA. Several other genes associated with the functionally important mechanisms relevant to bone healing, such as Wnt signalling (CTNNA1, FBX4, FZD6), angiogenesis (KDR), osteoclastogenesis (HSF2, MCL1) and proteolysis (HEXB, TPP1), were also differentially regulated. These results suggest that chemical (hydrophilic) modification of the SLA surface may result in more successful osseointegration through BMP signalling.

Spontaneous progression of ligature induced peri‐implantitis at implants with different surface roughness: an experimental study in dogs

Peri-implantitis is associated with the presence of submarginal plaque, soft-tissue inflammation and advanced breakdown of the supporting bone. The progression of peri-implantitis following varying periods of continuing plaque accumulation has been studied in animal models. The aim of the current experiment was to study the progression of peri-implantitis around implants with different surface roughness. In five beagle dogs, three implants with either a sandblasted acid-etched surface (SLA) or a polished surface (P) were installed bilaterally in the edentulous premolar regions. After 3 months on a plaque control regimen, experimental peri-implantitis was induced by ligature placement and plaque accumulation was allowed to progress until about 40% of the height of the supporting bone had been lost. After this 4-month period, ligatures were removed and plaque accumulation was continued for an additional 5 months. Radiographs of all implant sites were obtained before and after 'active' experimental peri-implantitis as well as at the end of the experiment. Biopsies were harvested and the tissue samples were prepared for light microscopy. The sections were used for histometric and morphometric examinations. The radiographic examinations indicated that similar amounts of bone loss occurred at SLA and P sites during the active breakdown period, while the progression of bone loss was larger at SLA than at polished sites following ligature removal. The histological examination revealed that both bone loss and the size of the inflammatory lesion in the connective tissue were larger in SLA than in polished implant sites. The area of plaque was also larger at implants with an SLA surface than at implants with a polished surface. It is suggested that the progression of peri-implantitis, if left untreated, is more pronounced at implants with a moderately rough surface than at implants with a polished surface.

Comparison of Human Mandibular Osteoblasts Grown on Two Commercially Available Titanium Implant Surfaces

Surface characteristics play a major role in determining tissue response to implants and therefore their clinical outcome. The aim of the present study was to compare two commercially available titanium surfaces: plasma sprayed (TPS) and sand-blasted, acid-etched surface (SLA). The surfaces were characterized by roughness testing, scanning electronic microscopy (SEM), Raman spectroscopy, and protein adsorption to determine their microtopographic and chemical properties. The effect of the surfaces on human mandibular osteoblasts was then studied in terms of cell morphology, adhesion, proliferation, and differentiation. Human osteoblasts from the mandible were cultured on these two surfaces and evaluated at 3, 6, 24, and 48 hours to determine cell attachment and morphology. Growth and differentiation kinetics were subsequently investigated by evaluating cell growth, alkaline phosphatase activity, osteocalcin and osteoprotegerin production at 7, 14, and 21 days. Although roughness was quite similar, the two surfaces presented strong differences in their topography, and cell morphology varied as a consequence. Osteoblasts on SLA appeared more elongated and spindle shaped than those on TPS, and their adhesion at 3 and 6 hours was weaker, but reached that of cells on TPS at hour 24. Cell proliferation was greater on SLA surfaces but differentiation parameters; i.e., alkaline phosphatase and osteocalcin, provided better results on TPS surfaces. Osteoprotegerin production was enhanced on TPS surfaces at days 14 and 21. Although cells grown on both surfaces exhibited good adhesion capabilities, a well-differentiated osteoblastic phenotype, and maintained a clear proliferation potential, our study suggests that plasma-sprayed treatment offers a better performance than SLA by creating, at least in the early phases, better conditions for tissue healing.