Sandblasted And Acid-etched Research Articles

The Effect of Platelet Proteins Released in Response to Titanium Implant Surfaces on Macrophage Pro-Inflammatory Cytokine Gene Expression.

Platelets are one of the earliest cell types to interact with surgically inserted titanium implants. This in vitro study investigated the effect of titanium surface-induced platelet releasate on macrophage cytokine gene expression. To mimic the in vivo temporal sequence of platelet arrival and protein production at the implant surface and the subsequent effect of these proteins on mediators of the immune response, the levels of platelet attachment and activation in response to culture on smooth polished, sandblasted and acid-etched (SLA), and hydrophilic-modified SLA (modSLA) titanium surfaces were first determined by microscopy and protein assay. The subsequent effect of the platelet-released proteins on human THP-1 macrophage cytokine gene expression was determined by polymerase chain reaction array after 1 and 3 days of macrophage culture on the titanium surfaces in platelet-releasate conditioned media. Platelet attachment was surface dependent with decreased attachment observed on the hydrophilic (modSLA) surface. The platelet releasate, when considered independently of the surface effect, elicited an overall pro-inflammatory response in macrophage cytokine gene expression, that is, the expression of typical pro-inflammatory cytokine genes such as TNF, IL1a, IL1b, and CCL1 was significantly up-regulated whereas the expression of anti-inflammatory cytokine genes such as IL10, CxCL12, and CxCL13 was significantly down-regulated. However, following platelet exposure to different surface modifications, the platelet releasate significantly attenuated the macrophage pro-inflammatory response to microrough (SLA) titanium and hastened an anti-inflammatory response to hydrophilic (modSLA) titanium. Theses results demonstrate that titanium surface topography and chemistry are able to influence the proteomic profile released by platelets, which can subsequently influence macrophage pro-inflammatory cytokine expression. This immunomodulation may be an important mechanism via which titanium surface modification influences osseointegration.

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.

Fabrication of compound-processed titanium surface and its effect of on osteoblast growth

Objective To process the titanium surface via sand-blasting,acid-etching and alkali-heating and investigate its effect on biological behavior of the osteoblasts.Methods The osteoblasts from SD rats in vitro were cultured in vitro on smooth titanium surface (control group),sandblasted and acid-etched (SLA) titanium surface (SLA group),and SLA plus alkali-heated (AH) titanium surface (SLA-AH group) respectively.Adhesion ability,proliferation and morphological changes of osteoblasts on titanium surface were observed respectively by cells counting,cell proliferation assay and scanning electron microscope.Levels of alkaline phosphatase (ALP),osteocalcin,type Ⅰ collagen,and core binding factor alpha 1 (Cbfαl) mRNA on titanium surface were compared among groups by real-time quantitative polymerase chain reaction (qRT-PCR).Results After 1,2,and 4 hours of co-culture,early-stage adhesion of osteoblasts in SLA-AH group was more than that in other two groups (F =5.635,28.621,124.037,P ＜ 0.05).In adhesion assay,the decreased absorbance value was observed in SLA and SLA-AH groups at day 7 compared with control group (F =12.682,P ＜ 0.05).Scanning electron microscopy showed oste oblasts in SLA-AH group presented better typical morphological characteristics,more stretch,and more lamellipodia and filopodia than other two groups.qRT-PCR results showed levels of ALP and Cbfa1 in SLA-AH group were higher than those in SLA group and control group at day 7,but lower than those in control group at day 14 and that levels of osteocalcin and collagen Ⅰ in SLA-AH group were higher than those in SLA and control groups at day 14.Conclusion SLA-AH-processed titanium surface enhances the attachment and differentiation of the rat osteoblasts,but fails to promote the proliferation of the osteoblasts. Key words: Titanium; Osteoblasts; Cell proliferation

Efficacy of standard (SLA) and modified sandblasted and acid-etched (SLActive) dental implants in promoting immediate and/or early occlusal loading protocols: a systematic review of prospective studies.

To assess the survival percentage, clinical and radiographic outcomes of sandblasted and acid-etched (SLA) dental implants and its modified surface (SLActive) in protocols involving immediate and early occlusal loading. MEDLINE, EMBASE and the Cochrane Oral Health Group's Trials Register CENTRAL were searched in duplicate up to, and including, June 2013 to include randomised controlled trials (RCTs) and prospective observational studies of at least 6-month duration published in all languages. Studies limited to patients treated with SLA and/or SLActive implants involving a treatment protocol describing immediate and early loading of these implants were eligible for inclusion. Data on clinical and/or radiographic outcomes following implant placement were considered for inclusion. Of the 447 potentially eligible publications identified by the search strategy, seven RCTs comprising a total of 853 implants (8% titanium plasma-sprayed, 41.5% SLA and 50.5% SLActive) and 12 prospective observational studies including 1394 SLA and 145 SLActive implants were included in this review. According to the Cochrane Collaboration's tool for assessing risk of bias, one of the studies was considered to be at a low risk of bias, whereas the remaining studies were considered to be at an unclear risk. Regarding the observational studies, all of them presented a medium methodological quality based on the Modified Newcastle-Ottawa scale. There were no significant differences reported in the studies in relation to implant loss or clinical parameters between the immediate/early loading and delayed loading protocols. Overall, 95% of SLA and 97% of SLActive implants still survive at the end of follow-up. Despite of the positive findings achieved by the included studies, few RCTs were available for analysis for SLActive implants. Study heterogeneity, scarcity of data and the lack of pooled estimates represent a limitation between studies' comparisons and should be considered when interpreting the present findings.

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.

Long‐term results of a three arms prospective cohort study on implants in periodontally compromised patients: 10‐year data around sandblasted and acid‐etched (SLA) surface

The aim of this study was to compare the long-term outcomes of sandblasted and acid-etched (SLA) implants in patients previously treated for periodontitis and in periodontally healthy patients (PHP). One hundred and forty-nine partially edentulous patients were consecutively enrolled in private specialist practice and divided into three groups according to their periodontal condition: PHP, moderately periodontally compromised patients (PCP) and severely PCP. Implants were placed to support fixed prostheses, after successful completion of initial periodontal therapy. At the end of active periodontal treatment (APT), patients were asked to follow an individualized supportive periodontal therapy (SPT) program. Diagnosis and treatment of peri-implant biological complications were performed according to cumulative interceptive supportive therapy (CIST). At 10 years, clinical and radiographic measures were recorded by two calibrated operators, blind to the initial patient classification, on 123 patients, as 26 were lost to follow up. The number of sites treated according to therapy modalities C and D (antibiotics and/or surgery) during the 10 years was registered. Six implants were removed for biological complications. The implant survival rate was 100% for PHP, 96.9% for moderate PCP and 97.1% for severe PCP. Antibiotic and/or surgical therapy was performed in 18.8% of cases in PHP, in 52.2% of cases in moderate PCP and in 66.7% cases in severe PCP, with a statistically significant differences between PHP and both PCP groups. At 10 years, the percentage of implants, with at least one site that presented a PD ≥ 6 mm, was, respectively, 0% for PHP, 9.4% for moderate PCP and 10.8% for severe PCP, with a statistically significant difference between PHP and both PCP groups. This study shows that SLA implants, placed under a strict periodontal control, offer predictable long-term results. Nevertheless, patients with a history of periodontitis, who did not fully adhere to the SPT, presented a statistically significant higher number of sites that required additional surgical and/or antibiotic treatment. Therefore, patients should be informed, from the beginning, of the value of the SPT in enhancing long-term outcomes of implant therapy, particularly those affected by periodontitis.

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.

Effects of Er: YAG laser irradiation on wettability, surface roughness, and biocompatibility of SLA titanium surfaces: an in vitro study

The erbium: yttrium-aluminum-garnet (Er: YAG) laser has been introduced as an effective method in the decontamination of implant surfaces. Data concerning the effects of the Er: YAG laser on the biological and surface properties of titanium are conflicting. Cellular behavior is greatly affected by surface properties, including composition, roughness, wettability, and morphology of the titanium surface. The aim of this study was to investigate the influence of the Er: YAG laser on the biocompatibility, surface roughness, and wettability of sandblasted and acid-etched (SLA) titanium surfaces. Twenty-one SLA titanium disks were irradiated by the Er: YAG laser at a pulse energy of 100mJ, with a pulse frequency of 10Hz under water irrigation for 1min. Cell viability, surface roughness, and wettability alterations were evaluated. Thirteen nonirradiated SLA disks were used as the control groups. Human osteoblast-like SaOs-2 cells were seeded onto the disks in culture media. Cell viability was evaluated using the methylthiazol tetrazolium assay. The surface roughness and wettability of the test and control groups were measured using profilometer and tensiometer devices, respectively. A significantly higher cell viability rate was observed in the test group (p = 0.032). The surface roughness was significantly reduced in the test group compared with the control group (p = 0.008). The surface wettability was significantly higher in the test group (p = 0.004). Within the limits of this study, the application of the Er: YAG laser with the previously described properties did not appear to have adverse effects on the biocompatibility of the SLA titanium surfaces. Application of this laser decreased the surface roughness and increased the wettability of the SLA titanium surfaces.

Polarization of modified titanium and titanium–zirconium creates nano-structures while hydride formation is modulated

The majority of titanium based bone-level dental implants available on the market today feature a sand-blasted and acid-etched (SBAE) surface that contains comparably high hydrogen levels. Cathodic polarization of titanium in acidic solutions is known to further increase titanium hydride on the surface. The aim of this study was to explore the effect of cathodic reduction on titanium (Ti) and titanium–zirconium (TiZr) with a SBAE surface in order to investigate the potential of such a process for further improving surfaces for bone anchored dental implants. Samples of both materials were cathodically polarized in acidic solution at different current densities and for different process times. Chemical analysis of the hydrogen levels by SIMS showed that cathodic reduction re-arranged the hydride already present on the surfaces from the etching process but could not significantly increase hydride levels. The hydrogen layer created by the preceding hot acid etching appeared to modulate further hydride creation. Analysis of the surface topography by SEM showed changes to the nano-topography of both materials after polarization. TiZr showed homogeneously distributed nano-spheres as they were already observed for TiZr SBAE at increased size of 80–100nm on the whole surface. By contrast, polarization of Ti created nano-nodules and nano-spheres of 150–200nm on the surface. These spheres were interconnected to form flower-like structures along the ridges and peaks of the surface. Moreover the flanks were covered by a rippled structure of isotropically distributed small-diameter (10–20nm) nano-nodules.

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.

Treatment With Various Ultrasonic Scaler Tips Affects Efficiency of Brushing of SLA Titanium Discs

The dental implant surface will be colonized by bacteria once it is exposed to the oral cavity. It is necessary to keep the titanium surface clean to prevent peri-implant diseases. Mechanical instrumentation is widely used, but this may cause damage to the implant surfaces. There is limited information whether surface change resulting from instrumentation influences the adherence of bacteria to the implant surface or influences the ease of removal of bacteria from the titanium surface by daily brushing. Therefore, this in vitro study was performed (1) to evaluate removal of Porphyromonas gingivalis from sand-blasted and acid-etched (SLA) titanium discs after the discs were instrumented by various ultrasonic scaler tips or brushed with a toothbrush with dentifrice using crystal violet assay and scanning electron microscopy (SEM), and (2) to assess the change of surface roughness after the treated discs were brushed with a toothbrush with dentifrice. SLA discs were treated with various ultrasonic scaler tips and a toothbrush. The titanium discs were incubated with P. gingivalis for 2 days after treatment (ultrasonic scales tips and brush) and then the disc surfaces were brushed for total of 40 seconds (20 seconds, two cycles) with a toothbrush with dentifrice. Differences in adhering bacteria were evaluated using crystal violet assay and SEM. Surface roughness of the treated discs after brushing with dentifrice was measured using confocal microscopy. The change of surface structure was observed after different treatment modalities. Removal of bacteria was increased with the longer time of brushing, and the ultrasonic metal tip group displayed a significantly lower number of bacteria after brushing when compared to other groups. Within the limits of this study, it may be suggested that when SLA surface is exposed to the oral cavity, it should firstly be treated with metal tips to smoothen the rough surface and thereby reduce attachment of bacteria and facilitate the removal of bacteria by daily oral hygiene procedures.

A 5- to 6-year radiological evaluation of titanium plasma sprayed/sandblasted and acid-etched implants: results from private practice

This study aimed to determine bone level changes after 5-6 years of follow-up for a large group of one-stage dental implants consecutively placed in private practice. Potential confounding factors influencing crestal bone loss (CBL) were also assessed. A total of 378 transmucosal Straumann implants in 174 patients were examined radiographically. Half of the study population (189 implants) had a titanium plasma sprayed (TPS) surface, and the other half (189 implants) were sandblasted and acid-etched (SLA). Mean CBL was measured from 5 to 6 years post-operative radiographs on the basis of known implant landmarks. Correlations of increased CBL with various independent variables were also investigated. Statistical analyses were performed using generalized estimating equations. Radiographic measurements showed a CBL ≤ 1.5 mm for 65% of studied implants. A CBL > 1.5 mm was found for 28% of implants, while 7% of implants had a CBL ≥ 3 mm. Three factors significantly influenced CBL (P < 0.05): implant surface texture (TPS > SLA), smoking status (smokers > non-smokers), and implant location (anterior > posterior). CBL was ≤1.5 mm after 5-6 years for the majority of followed implants. For implants with a CBL > 1.5 mm, statistically significant correlations were found for TPS surface type, anterior jaw locations, and smoking. Implant length did not influence CBL.

Biologic stability of plasma ion-implanted miniscrews

ObjectiveTo gain basic information regarding the biologic stability of plasma ion-implanted miniscrews and their potential clinical applications.MethodsSixteen plasma ion-implanted and 16 sandblasted and acid-etched (SLA) miniscrews were bilaterally inserted in the mandibles of 4 beagles (2 miniscrews of each type per quadrant). Then, 250 - 300 gm of force from Ni-Ti coil springs was applied for 2 different periods: 12 weeks on one side and 3 weeks contralaterally. Thereafter, the animals were sacrificed and mandibular specimens including the miniscrews were collected. The insertion torque and mobility were compared between the groups. The bone-implant contact and bone volume ratio were calculated within 800 µm of the miniscrews and compared between the loading periods. The number of osteoblasts was also quantified. The measurements were expressed as percentages and analyzed by independent t-tests (p < 0.05).ResultsNo significant differences in any of the analyzed parameters were noted between the groups.ConclusionsThe preliminary findings indicate that plasma ion-implanted miniscrews have similar biologic characteristics to SLA miniscrews in terms of insertion torque, mobility, bone-implant contact rate, and bone volume rate.

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.

10‐Year Survival and Success Rates of 511 Titanium Implants with a Sandblasted and Acid‐Etched Surface: A Retrospective Study in 303 Partially Edentulous Patients

This retrospective study assessed the 10-year outcomes of titanium implants with a sandblasted and acid-etched (SLA) surface in a large cohort of partially edentulous patients. Records of patients treated with SLA implants between May 1997 and January 2001 were screened. Eligible patients were contacted and invited to undergo a clinical and radiologic examination. Each implant was classified according to strict success criteria. Three hundred three patients with 511 SLA implants were available for the examination. The mean age of the patients at implant surgery was 48 years. Over the 10-year period, no implant fracture was noted, whereas six implants (1.2%) were lost. Two implants (0.4%) showed signs of suppuration at the 10-year examination, whereas seven implants had a history of peri-implantitis (1.4%) during the 10-year period, but presented with healthy peri-implant soft tissues at examination. The remaining 496 implants fulfilled the success criteria. The mean Plaque Index was 0.65 (±0.64), the mean Sulcus Bleeding Index 1.32 (±0.57), the mean Probing Depth 3.27 mm (±1.06), and the mean distance from the implant shoulder to the mucosal margin value -0.42 mm (±1.27). The radiologic mean distance from the implant shoulder to the first bone-to-implant contact was 3.32 mm (±0.73). The present retrospective analysis resulted in a 10-year implant survival rate of 98.8% and a success rate of 97.0%. In addition, the prevalence of peri-implantitis in this large cohort of orally healthy patients was low with 1.8% during the 10-year period.

A comparative analysis of sandblasted and acid etched and polished titanium surface on enhancement of osteogenic potential: An in vitro study

Purpose: Establishment of titanium surface treatment and comparison of surface roughness and osteogenic potential of commercially pure titanium. Materials and Methods: Twenty commercially pure grade 2 titanium disks of similar design and dimensions were divided into two groups. Smooth samples were assigned as control group (Group S). The second group (Group SLA) samples were sand-blasted and etched with different acids. Scanning Electron Microscopy (SEM) at ×500 was performed to observe the surface morphology. The surface roughness of samples was evaluated with surface profilometer. To evaluate the effect of surface treatment, samples from each group underwent cell culture study using human osteosarcoma osteoblast cell lines (HOS). SEM of one sample from each group was performed at ×500 to observe the cell morphology and cell attachment. Results: Sand-blasted and acid-etched (SLA) surface was rougher in comparison to the smooth surface. SEM result of sand-blasted and acid-etched surface (Group SLA) showed that cell sheets were able to adhere inside the valleys suggesting excellent attachment osseointegration to rough surface.Conclusion: This approach to develop sand-blasted and acid-etched surface was successful in uniform distribution of human osteosarcoma osteoblast cell lines (HOS) suggesting excellent osseointegration.

Biomechanical evaluation of a microstructured zirconia implant by a removal torque comparison with a standard Ti‐SLA implant

The purpose of this study was to evaluate the biomechanical bone tissue response to novel microstructured zirconia implants in comparison to sandblasted and acid-etched (SLA) titanium implants through the analysis of removal torque (RTQ) measurements. Ti-SLA implants with a sandblasted, large-grit and acid-etched surface were compared with zirconia implants with an acid-etched surface. All implants had the same shape, a diameter of 4.1 mm and a length of 10 mm. A total of 136 implants were placed in the maxillae of 17 miniature pigs. Six animals were sacrificed after both 4 and 8 weeks and five animals were sacrificed after 12 weeks, thus providing a total of 102 implants for RTQ testing (34 implants were reserved for future histological analysis). The RTQ analysis was successfully performed, using a mixed model regression with P-values calculated using the nonparametric Brunner-Langer method, on 100 of the 102 implants, two were excluded from the analysis. The adjusted mean RTQ values for Ti-SLA implants were 131 Ncm (95% CI: 107-155) at 4 weeks, 128 Ncm (108-148) Ncm at 8 weeks, and 180 Ncm (153-207 Ncm) at 12 weeks of healing, whereas RTQ values for the zirconia implants were 110 Ncm (86-134), 97 Ncm (76-118) and 147 Ncm (121-174) at the corresponding time intervals. A comparison of the implant materials resulted in P-values of P = 0.114 at 4 weeks, P = 0.034 at 8 weeks and P = 0.105 at 12 weeks (significance set at P < 0.05). Within the limits of the present study, it could be confirmed that the biomechanical bone-tissue response of the investigated zirconia implants is non-inferior to that of the well-documented, roughened titanium surface, at each time point, within the set tolerance. There were no statistically significant differences between the two materials after a healing period of 4 and 12 weeks. The RTQ values of both implant types increased significantly from the 8-week to the 12-week time point.

Osteoblast Behavior on Hierarchical Micro-/Nano-Structured Titanium Surface

In the present work, osteoblast behavior on a hierarchical micro-/nano-structured titanium surface was investigated. A hierarchical hybrid micro-/nano-structured titanium surface topography was produced via Electrolytic Etching (EE). MG-63 cells were cultured on disks for 2 h to 7 days. The osteoblast response to the hierarchical hybrid micro-/nano-structured titanium surface was evaluated through the osteoblast cell morphology, attachment and proliferation. For comparison, MG-63 cells were also cultured on Sandblasted and Acid-etched (SLA) as well as Machined (M) surfaces respectively. The results show significant differences in the adhesion rates and proliferation levels of MG-63 cells on EE, SLA, and M surfaces. Both adhesion rate and proliferation level on EE surface are higher than those on SLA and M surfaces. Therefore, we may expect that, comparing with SLA and M surfaces, bone growth on EE surface could be accelerated and bone formation could be promoted at an early stage, which could be applied in the clinical practices for immediate and early-stage loadings.

Alkali treatment of microrough titanium surfaces affects macrophage/monocyte adhesion, platelet activation and architecture of blood clot formation

Titanium implants are most commonly used for bone augmentation and replacement due to their favorable osseointegration properties. Here, hyperhydrophilic sand-blasted and acid-etched (SBA) titanium surfaces were produced by alkali treatment and their responses to partially heparinized whole human blood were analyzed. Blood clot formation, platelet activation and activation of the complement system was analyzed revealing that exposure time between blood and the material surface is crucial as increasing exposure time results in higher amount of activated platelets, more blood clots formed and stronger complement activation. In contrast, the number of macrophages/monocytes found on alkali-treated surfaces was significantly reduced as compared to untreated SBA Ti surfaces. Interestingly, when comparing untreated to modified SBA Ti surfaces very different blood clots formed on their surfaces. On untreated Ti surfaces blood clots remain thin (below 15 mm), patchy and non-structured lacking large fibrin fiber networks whereas blood clots on differentiated surfaces assemble in an organized and layered architecture of more than 30 mm thickness. Close to the material surface most nucleated cells adhere, above large amounts of non-nucleated platelets remain entrapped within a dense fibrin fiber network providing a continuous cover of the entire surface. These findings might indicate that, combined with findings of previous in vivo studies demonstrating that alkali-treated SBA Ti surfaces perform better in terms of osseointegration, a continuous and structured layer of blood components on the blood-facing surface supports later tissue integration of an endosseous implant.

Stability, marginal bone loss and survival of standard and modified sand-blasted, acid-etched implants in bilateral edentulous spaces: a prospective 15-month evaluation

Chemical modification of the already proven sand-blasted and acid-etched (SLA) implant had increased its surface wettability and consequent early-term osseointegration characteristics. The aim of this clinical trial was to compare the stability changes, success, survival, peri-implant parameters and marginal bone loss (MBL) of the early-loaded standard (SLA) and modified sand-blasted, acid-etched (modSLA) implants. A total of 96 SLA and modSLA implants were placed in a bi-lateral, cross-arch position to the jaws of 22 patients. Resonance frequency analysis (RFA) was used to measure the implant stability in the surgery and following healing after 1, 3 and 6 weeks. At the stage of loading, a panoramic X-ray was obtained and RFA measurement was repeated for all implants. Implants were restored by metal-ceramic crowns and followed for 1 year to determine the success, survival rate, peri-implant parameters and MBL. Results were compared by one- and two-way ANOVA, log-rank test and generalized linear mixed models (P < 0.05). One modSLA implant was lost after 3 weeks following the surgery yielding to a 100 and 97.91% success rate for SLA and modSLA implants, respectively (P = 0.323). At the loading stage, modSLA implants showed significantly lower MBL (0.18 ± 0.05 mm) than SLA implants (0.22 ± 0.06 mm; P = 0.002). In the loading stage, RFA value of the modSLA implants (60.42 ± 6.82) was significantly higher than the both implant types in the surgical stage (55.46 ± 8.29 and 56.68 ± 8.19), and following 1 (56.08 ± 7.01 and 55.60 ± 9.07) and 3 weeks of healing (55.94 ± 5.95 and 55.40 ± 6.50 for SLA and modSLA implants, respectively). modSLA implants demonstrated a better stability and a reduced MBL at the loading stage. Both SLA and modSLA implants demonstrated a favorable success and survival at the end of 15-month follow-up.