Double Acid Etching Research Articles

Comparative clinical evaluation of the stability of implants using double acid etching treatment with and without the addition of fluoride solution: A randomized clinical trial.

Osseointegration depends on primary stability, and further, implant surface modifications may improve secondary stability. This randomized clinical trial evaluates whether adding a fluoride solution enhances the implant stability. Stability of dental implants with two different types of surface treatments was compared utilizing resonance frequency analysis (RFA). Twelve patients were recruited: eight females and four males with an average age of 58.3 years and they received either double acid etched implants (control: Porus Implant, Sistema Conexão) and double acid etched implants containing fluoride on their surfaces (test: Porus Nano Implant, Sistema Conexão). Each patient received one implant from the test category and another implant from the control category, resulting in 24 implants in this study. RFA, utilizing Osstell was used to assess the implant stability, immediately after the placement of implant and 15, 30 and 45 days post-implant placement. At the initial time, there was no difference between the test and control groups regarding the ISQ. However, after 15, 30, and 45 days, ISQ values for the test group were significantly higher than the control group. When using implants without fluoride addition, it was observed that after 15 days, the ISQ values were lower than those found at the initial time, but after 30 days, values matched the initial. Concerning the test group results, the ISQ values from T0 (immediately after implant placement) to T3 (45 days after implant placement) always increased from every period of evaluation. It was concluded that double acid etched implants with surfaces containing fluoride solution increases the implant stability quotient, compared to implants with fluoride-free double acid etched surfaces.

The Action of Angiocrine Molecules Sourced from Mechanotransduction-Related Endothelial Cell Partially Explain the Successful of Titanium in Osseointegration.

Since Branemark's findings, titanium-based alloys have been widely used in implantology. However, their success in dental implants is not known when considering the heterogenicity of housing cells surrounding the peri-implant microenvironment. Additionally, they are expected to recapitulate the physiological coupling between endothelial cells and osteoblasts during appositional bone growth during osseointegration. To investigate whether this crosstalk was happening in this context, we considered the mechanotransduction-related endothelial cell signaling underlying laminar shear stress (up to 3 days), and this angiocrine factor-enriched medium was harvested further to use exposing pre-osteoblasts (pOb) for up to 7 days in vitro. Two titanium surfaces were considered, as follows: double acid etching treatment (w_DAE) and machined surfaces (wo_DAE). These surfaces were used to conditionate the cell culture medium as recommended by ISO10993-5:2016, and this titanium-enriched medium was later used to expose ECs. First, our data showed that there is a difference between the surfaces in releasing Ti molecules to the medium, providing very dynamic surfaces, where the w_DAE was around 25% higher (4 ng/mL) in comparison to the wo_DAE (3 ng/mL). Importantly, the ECs took up some of this titanium content for up to 3 days in culture. However, when this conditioned medium was used to expose pOb for up to 7 days, considering the angiocrine factors released from ECs, the concentration of Ti was lesser than previously reported, reaching around 1 ng/mL and 2 ng/mL, respectively. Thereafter, pOb exposed to this angiocrine factor-enriched medium presented a significant difference when considering the mechanosignaling subjected to the ECs. Shear-stressed ECs showed adequate crosstalk with osteoblasts, stimulating the higher expression of the Runx2 gene and driving higher expressions of Alkaline phosphatase (ALP), bone sialoprotein (BSP), and osteocalcin. Mechanotransduction-related endothelial cell signaling as a source of angiocrine molecules also stimulated the higher expression of the Col3A1 gene in osteoblasts, which suggests it is a relevant protagonist during trabecular bone growth. In fact, we investigated ECM remodeling by first evaluating the expression of genes related to it, and our data showed a higher expression of matrix metalloproteinase (MMP) 2 and MMP9 in response to mechanosignaling-based angiocrine molecules, independent of considering w_DAE or the wo_DAE, and this profile reflected on the MMP2 and MMP9 activities evaluated via gelatin-based zymography. Complimentarily, the ECM remodeling seemed to be a very regulated mechanism in mature osteoblasts during the mineralization process once both TIMP metallopeptidase inhibitor 1 and 2 (TIMP1 and TIMP2, respectively) genes were significantly higher in response to mechanotransduction-related endothelial cell signaling as a source of angiocrine molecules. Altogether, our data show the relevance of mechanosignaling in favoring ECs' release of bioactive factors peri-implant, which is responsible for creating an osteogenic microenvironment able to drive osteoblast differentiation and modulate ECM remodeling. Taking this into account, it seems that mechanotransduction-based angiocrine molecules explain the successful use of titanium during osseointegration.

Bacterial and Cellular Response to Yellow-Shaded Surface Modifications for Dental Implant Abutments.

Dental implants have dramatically changed the rehabilitation procedures in dental prostheses but are hindered by the possible onset of peri-implantitis. This paper aims to assess whether an anodization process applied to clinically used surfaces could enhance the adhesion of fibroblasts and reduce bacterial adhesion using as a reference the untreated machined surface. To this purpose, four different surfaces were prepared: (i) machined (MAC), (ii) machined and anodized (Y-MAC), (iii) anodized after sand-blasting and acid etching treatment (Y-SL), and (iv) anodized after double acid etching (Y-DM). All specimens were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Moreover, the mean contact angle in both water and diiodomethane as well as surface free energy calculation was assessed. To evaluate changes in terms of biological responses, we investigated the adhesion of Streptococcus sanguinis (S. sanguinis) and Enterococcus faecalis (E. faecalis), fetal bovine serum (FBS) adsorption, and the early response of fibroblasts in terms of cell adhesion and viability. We found that the anodization reduced bacterial adhesion, while roughened surfaces outperformed the machined ones for protein adsorption, fibroblast adhesion, and viability independently of the treatment. It can be concluded that surface modification techniques such as anodization are valuable options to enhance the performance of dental implants.

Evaluation of Bone Response to a Nano HA Implant Surface on Sinus Lifting Procedures: Study in Rabbits.

The aim of this study was to evaluate the bone response to two different implant surfaces on sinus lift procedures in rabbits. Bilateral sinus lifting with inorganic bovine bone associated with collagen membrane and immediate implantation were performed in 16 rabbits. Custom mini-implants were randomly installed in the prepared sites: one side received a double acid-etched (DAE) surface and the other a nano-hydroxyapatite (NHA) surface. The animals were euthanized 30 and 60 days after surgery, and biopsies were collected for microtomographic and histomorphometric analysis. After 30 days, no intra- and inter-group statistical differences were observed in microtomographic analysis, while at 60 days, bone analysis showed statistically significant differences between groups (p < 0.05) for all the evaluated parameters. Histomorphometric analysis showed, after 30 days, mean % of Bone-to-Implant Contact (BIC) for DAE and NHA of 31.70 ± 10.42% vs. 40.60 ± 10.22% (p > 0.05), respectively; for % of Bone Area Fraction Occupancy (BAFO), mean values were 45.43 ± 3.597% for DAE and 57.04 ± 5.537% for NHA (p < 0.05). After 60 days, mean %BIC and %BAFO for DAE and NHA implants were statistically significant (p < 0.05). The NHA surface showed superior biological features compared to the DAE treatment, promoting higher bone formation around the implants in an experimental model of bone repair in a grafted area.

A Novel 3D Titanium Surface Produced by Selective Laser Sintering to Counteract Streptococcus oralis Biofilm Formation

The topography of implant surfaces influences the interaction relationship between material and bacteria. The aim of this work was to characterize a novel 3D titanium surface, produced using Selective Laser Sintering (SLS), and to compare the bacterial interaction with machined and double acid etching (DAE) discs. The surface was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and Energy Dispersive X-ray Spectrometry (EDX). The wettability was measured using the sessile method. The microbiological investigation consisted in the cultivation of a bacterial pioneer, Streptococcus oralis, on titanium surfaces, previously covered by human saliva in order to form the acquired pellicle. Then, colony forming units (CFUs), biofilm biomass quantification, analyses of viable and dead cells, and SEM observation were determined after 24 h of S. oralis biofilm formation on the different discs. A significantly higher nano-roughness with respect to the other two groups characterized the novel 3D surface, but the wettability was similar to that of machined samples. The microbiological assays demonstrated that the 3D discs reported significantly lower values of CFUs and biofilm biomass with respect to machined surfaces; however, no significant differences were found with the DAE surfaces. The live/dead staining confirmed the lower percentage of living cells on DAE and 3D surfaces compared with the machined. This novel 3D surface produced by SLS presented a high antiadhesive and antibiofilm activity.

Hydrogen storage capability of porous silicon powder fabricated from Al–Si alloy

Porous silicon powder has been fabricated from an Al–Si alloy by etching in strong acids, and its hydrogen storage capacity has been studied. Double acid etching in the fabrication and nickel blending have been proposed to further enhance the hydrogen storage capacity of the etched powder. The etching effectively removed the aluminum from the Al–Si alloy to form a porous Si structure, with a large increase in surface area. After charging under a hydrogen pressure of 3.7 MPa at 150 °C, the hydrogen uptake of double-etched and Ni-blend porous silicon samples was 0.81 wt%, which was >13 times higher than that of the as-received Al–Si alloy (0.06 wt%). The percentage of retained hydrogen after desorption was also largely decreased. The results of this study provide strong evidence on the potential of using porous silicon powder from Al–Si alloy as a cost-effective solid-state storage material for hydrogen.

Wettability of implant surfaces: Blood vs autologous platelet liquid (APL)

Physicochemical properties of titanium surfaces, such as wettability, influence protein binding, cell adhesion and proliferation, therefore osseointegration. The objective of this study was to investigate the wetting behaviour of two titanium surfaces, sandblasted and double acid etched (group S/E) and sandblasted (group S), using blood and Autologous Platelet Liquid (APL). Surface morphology and roughness were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The static contact angle (CA) was assessed with the sessile drop technique. The work also evaluates, with SEM observation, the fibrin clot structure that develops from blood and APL, knowing that a greater clot, firmly attached to an implant can facilitate cell migration to the implant interface. Both surfaces exhibited a hydrophobic behaviour, regardless of the wetting liquid used, but the S surface showed higher CA values for both the wetting fluids used. Lower CA values on the S/E surface are attributable to the different surface energy, which depends on different surface topography (the S surfaces were rougher) and on chemical composition. No statistically significant differences between the values of CA of blood and APL were found on the same surfaces. The clot obtained from whole blood differs from the APL clot due to a different cellular composition and fibrin density.

Comparative Evaluation of Implants with Different Surface Treatments Placed in Human Edentulous Mandibles: A 1-Year Prospective Study.

The aims of this study were to analyze prospectively and comparatively the peri-implant bone crest levels, bone density, stability and success rate of implants with different surface treatments in human edentulous mandibles. Twenty edentulous patients were selected. Four different implants were placed between the mental foramen. Four groups were evaluated: (1) laser-modified surface (LASER), (2) surface modified by laser with deposition of apatites (LASER + HA), (3) surface modified by double acid etching (ACID, Implacil De Bortoli) and (4) surface modified by sandblasting and acid etching (SLActive®, Straumann). Clinical, radiographic, resonance frequency and tomographic analyses were used. After 4months, mandibular fixed implant prostheses were installed. Clinical and radiographic analyses were performed at times T0 (immediately after implant placement), T1 (15days), T2 (30days), T3 (60days), T4 (90days), T5 (120days), T6 (180days) and T7 (360days), post-implant placement. The resonance frequency analysis (RFA) was measured at T0, T4, T6 and T7. The tomographic analysis was performed at T0, T4 and T7. In the radiographic bone density analysis, a statistical difference was found between the SLActive® and LASER + HA groups at T4 (p < 0.05). Statistical differences were observed in RFA at T4 (90days), between the SLActive® and LASER groups (p < 0.05) and between the SLActive® and LASER + HA groups (p < 0.05). At T6 and T7, statistical differences were found between the SLActive® group and all other implant surfaces (p < 0.01). The experimental surfaces analyzed showed encouraging positive outcomes compared to those of the SLActive® surface. Long-term follow-up should be performed to confirm these results.

Microscopic Characterization of Bioactivate Implant Surfaces: Increasing Wettability Using Salts and Dry Technology.

The surface topography of dental implants plays an important role in cell-surface interaction promoting cell adhesion, proliferation and differentiation influencing osseointegration. A hydrophilic implant leads to the absorption of water molecules and subsequently promotes the adhesion of cells to the implant binding protein. Dried salts on the implant surfaces allow one to store the implant surfaces in a dry environment while preserving their hydrophilic characteristics. This process has been identified as “dry technology”. The aim of the present study is to describe from a micrometric and nanometric point of view the characteristics of this new bioactivated surface obtained using salts dried on the surface. Topographic analysis, energy-dispersive X-ray spectroscopy, and contact angle characterization were performed on the samples of a sandblasted and dual acid-etched surface (ABT), a nanosurface (Nano) deriving from the former but with the adding of salts air dried and a nanosurface with salts dissolved with distilled water (Nano H2O). The analysis revealed promising results for nanostructured surfaces with increased wettability and a more articulated surface nanotopography than the traditional ABT surface. In conclusion, this study validates a new promising ultra-hydrophilic nano surface obtained by sandblasting, double acid etching and surface salt deposition using dry technology.

Hydrogen Storage Capability of Porous Silicon Powder Fabricated from Al-Si Alloy

Porous silicon powder has been fabricated from an Al-Si alloy by etching in strong acids, and its hydrogen storage capacity has been studied. A double acid etching in the fabrication, as well as nickel catalyst addition have been proposed to further enhance the hydrogen storage capacity of the powder. The hydrogen uptake after the double-etching and Ni blending was found to increase and achieved a maximum uptake of 18.6 H atomic % (0.81 H wt%), which was 4 times more than the hydrogen sorption capacity of the sample after single acid etching. The results of this study provide a strong evidence on the potential of porous silicon powder from Al-Si alloy to be a cost-effective solid-state storage material for hydrogen.

Nanometric Deposition of Fluoride Ions on Titanium Alloys and its Influence on In Vitro Bacterial Adhesion and Viability

Bacterial colonization plays a key role on the pathogenesis of peri-implantitis and may be influenced by titanium surface topography. The aim of this in vitro study was to evaluate the influence of titanium topography after fluoride ions deposition in the bacterial colonization. Machined (M), double acid-etched (DE) and double acid-etched surface with fluoride ions deposition (Nano F-) were analyzed by scanning electron microscopy, contact angle and roughness (Ra). Streptococcus mutans viability was quantified by Live/Dead Baclight bacterial viability kit. The mean Ra/contact angle values were 0.20 μm/69.13°, 0.53 μm /92.82° and 0.56 μm/94.33° for M, DE and Nano F-, respectively. M surface presented significantly lower live bacterial counts when compared to the Nano F- surface (p=0.007). The dead bacteria count was higher on the Nano F- surface (p=0.001) than on the M and DE surfaces. Crystalline deposition of fluoride ions (Nano F-) promoted an increase in dead bacteria on the tested titanium surface.

Histological and Nanomechanical Properties of a New Nanometric Hydroxiapatite Implant Surface. An In Vivo Study in Diabetic Rats.

Implant therapy is a predictable treatment to replace missing teeth. However, the osseointegration process may be negatively influenced by systemic conditions, such as diabetes mellitus (DM). Microtopography and implant surface developments are strategies associated to better bone repair. This study aimed to evaluate, in healthy and diabetic rats, histomorphometric (bone to implant contact = %BIC; and bone area fraction occupancy = %BAFO) and nanomechanical (elastic modulus = EM; and hardness = H) bone parameters, in response to a nanometric hydroxyapatite implant surface. Mini implants (machined = MAC; double acid etched = DAE, and with addition of nano-hydroxyapatite = NANO) were installed in tibias of healthy and diabetic rats. The animals were euthanized at 7 and 30 days. NANO surface presented higher %BIC and %BAFO when compared to MAC and DAE (data evaluated as a function of implant surface). NANO surface presented higher %BIC and %BAFO, with statistically significant differences (data as a function of time and implant surface). NANO surface depicted higher EM and H values, when compared to machined and DAE surfaces (data as a function of time and implant surface). Nano-hydroxyapatite coated implants presented promising biomechanical results and could be an important tool to compensate impaired bone healing reported in diabetics.

Morphological and Chemical Characterization of Titanium and Zirconia Dental Implants with Different Macro- and Micro-Structure

Background: The aim of this study was to evaluate the macro- and micro-structure and the chemical composition of the surface of 5 different commercially available dental implants. Roughness values were also calculated. Materials and Methods: 1 zirconia implant (NobelPearl of Nobel Biocare) and 4 titanium implants, Syra (Sweden&amp;Martina), Prama (Sweden&amp;Martina), T3 (Biomet 3i), and Shard (Mech&amp;Human), were analyzed through SEM-EDX analysis and quantitative evaluation of surface roughness (1 sample), and XPS chemical analysis (1 sample). Surface roughness was quantitatively assessed using the stereo-SEM method (SSEM). The following area roughness parameters were calculated, according to ISO25178: Sa, Sz, and Sdr. Results: From the SEM observations, all the implants analyzed presented modern well-developed micro-structures as the result of the specific process of double acid etching alone or combined with other additional treatments. Roughness values were generally greater at the level of the implant body and lower at the collar. The chemical characterization of the implant surfaces exhibited excellent results for all of the implants and indicated good care in the production processes. Conclusions: All the samples were well-conceived in terms of topography and surface roughness, and clean in terms of chemical residues.

Osteoblastic Cell Behavior and Early Bacterial Adhesion on Macro-, Micro-, and Nanostructured Titanium Surfaces for Biomedical Implant Applications.

Surface treatments may significantly affect physical-chemical properties and surface biologic responses. This study aimed to investigate the influence of alterations in the physical-chemical properties of pure titanium with different surface topographies on biocompatibility and early microbiologic response. Titanium disks were exposed to five different surface treatments created through acid etching and anodizing methods. Surface morphology, 2D and 3D roughness, wettability, biocompatibility, and cell viability were evaluated. Osteoblast adhesion and bacterial adhesion tests were also executed. Data were statistically analyzed using analysis of variance followed by Tukey test, roughness (P < .05), and bacterial proliferation (P < .05). Five different surface morphologies were developed; double acid etching was shown to be significantly rougher than the others. The 2D roughness measurements were shown to be less consistent than the 3D measurements. All surfaces presented biocompatibility to allow cell behavior and differentiation. Osteoblasts presented better evolution in terms of adhesion and behavior in the nanomorphologies. High roughness significantly increased bacterial adhesion. Surface treatments may critically alter titanium properties and morphology. Therefore, roughness measurements with a wide area should be used in their evaluation. Nanotextured surfaces show a positive effect on bone cells and antibacterial response; their application is suggested when considering surface texturization for biomedical implants.

Improved osteointegration by SEW2871-encapsulated multilayers on micro-structured titanium via macrophages recruitment and immunomodulation

The main task for medical-used titanium researches is to improve the in vivo osteointegration. In addition to mesenchymal stromal cells (MSCs)-osteoblasts lineage, macrophages also undertake irreplaceable roles in the osteointegration process of a titanium implant. The timely recruitment and efficient immunomodulation of macrophages is important. In this work, to firstly endow macrophages recruitment ability and immunomodulation effects to titanium, we fabricated a micro-structured titanium via a double acid etching method. Then a gelatin-chitosan multilayer contained SEW2871 (a macrophage recruitment agent) was constructed on the micro-structured titanium by a layer-by-layer (LBL) self-assembly technique. According to our results, the prepared samples effectively induced macrophages migration when SEW2871 was slowly released. The anti-inflammatory response of macrophages was enhanced and the pro-inflammatory response was alleviated, which were attributed to the changed surface roughness and wettability. This immunomodulation effects of macrophages further improved the osteogenic differentiation of MSCs in vitro and obtained a better osteointegration in vivo after 6 weeks of implantation. Therefore, this study demonstrated that a favorable osteointegration of titanium materials could also be achieved by regulating macrophages recruitment and immunomodulation, which implying a potential strategy for titanium implants amelioration.

The Evaluation of Osteoblastic Cell Behavior on Treated Titanium Surface

Background: There are several potential advantages in optimizing the initial events of osseointegration in the benefit of clinical outcome. Objective: The objective of the present study was to evaluate the behavior of osteoblastic cells on surfaces treated by double acid etching using HNO3 and H2SO4. Methods: Commercially pure titanium (grade 4) discs measuring 6 mm in diameter and 2 mm in thickness were used. The discs were divided into two groups: machined group and double acid-etched discs (HNO3 and H2SO4). Surface characteristics were assessed using Scanning Electron Microscopy. Pre-osteoblastic MC3T3-E1 cells were used for cell culture on the tested surfaces to assess proliferation, viability (MTT), as well as secretion (ELISA) and cytoplasmic expression (Western blot) of type I collagen. Results: The data obtained were analyzed using t-test or two-way ANOVA followed by Bonferroni’s test at 95% significance. The titanium surfaces showed average roughness values for the machined and treated surfaces of 0.29 and 1.16, respectively (p&lt;0.05). An increase in cell proliferation was observed, which was corroborated by the viability assay. Both type I collagen secretion and intracellular expression were higher on the double acid-etched surface compared to the machine surfaces (p&lt;0.05). Conclusion: Implant surfaces treated by double acid etching positively affected the early events of the interaction between titanium and osteoblastic cells, suggesting optimization of osseintegration.

The Evaluation of Osteoblastic Cell Behavior on Treated Titanium Surface

Background: There are several potential advantages in optimizing the initial events of osseointegration in the benefit of clinical outcome. Objective: The objective of the present study was to evaluate the behavior of osteoblastic cells on surfaces treated by double acid etching using HNO3 and H2SO4. Methods: Commercially pure titanium (grade 4) discs measuring 6 mm in diameter and 2 mm in thickness were used. The discs were divided into two groups: machined group and double acid-etched discs (HNO3 and H2SO4). Surface characteristics were assessed using Scanning Electron Microscopy. Pre-osteoblastic MC3T3-E1 cells were used for cell culture on the tested surfaces to assess proliferation, viability (MTT), as well as secretion (ELISA) and cytoplasmic expression (Western blot) of type I collagen. Results: The data obtained were analyzed using t-test or two-way ANOVA followed by Bonferroni’s test at 95% significance. The titanium surfaces showed average roughness values for the machined and treated surfaces of 0.29 and 1.16, respectively (p&lt;0.05). An increase in cell proliferation was observed, which was corroborated by the viability assay. Both type I collagen secretion and intracellular expression were higher on the double acid-etched surface compared to the machine surfaces (p&lt;0.05). Conclusion: Implant surfaces treated by double acid etching positively affected the early events of the interaction between titanium and osteoblastic cells, suggesting optimization of osseintegration.

Anodization as a promising surface treatment for drug delivery implants and a non-cytotoxic process for surface alteration: a pilot study.

Aim Surface treatments use industrial processes in which surface contamination can occur. In this context, this study aimed to demonstrate a surface treatment process, from laboratory samples and clinical implants, named anodizing, analyze their tendencies to surface contamination as well as their properties.Materials and Methods Laboratorial samples of pure titanium were anodized. Investigated by scanning microscopy (SEM), dispersive energy spectroscopy (EDS) and wettability tests. Four implant systems available in the current market were chosen by different surface treatments (anodizing, double acid etching and particle blasting) and investigated by SEM/EDS.Results Laboratory samples showed a nanomorphology surface, free of contaminants and good liquid/surface interaction. The implant system with anodization treatment did not present elements outside the standards. However, the implants treated with acid attack and blasting were found different chemical elements like aluminum and magnesium.Conclusions Anodizing proved to be a contaminant-free surface treatment both in the laboratory and clinical implants. In addition, its promising property of owning TiO2 nanotubes suggests an inherent evolution to biomedical implants for drug delivery systems other than all surface treatments developed to date.

Influence of Titanium Oxide Pillar Array Nanometric Structures and Ultraviolet Irradiation on the Properties of the Surface of Dental Implants-A Pilot Study.

Aim: Titanium implants are commonly used as replacement therapy for lost teeth and much current research is focusing on the improvement of the chemical and physical properties of their surfaces in order to improve the osseointegration process. TiO2, when it is deposited in the form of pillar array nanometric structures, has photocatalytic properties and wet surface control, which, together with UV irradiation, provide it with superhydrophilic surfaces, which may be of interest for improving cell adhesion on the peri-implant surface. In this article, we address the influence of this type of surface treatment on type IV and type V titanium discs on their surface energy and cell growth on them. Materials and methods: Samples from titanium rods used for making dental implants were used. There were two types of samples: grade IV and grade V. In turn, within each grade, two types of samples were differentiated: untreated and treated with sand blasting and subjected to double acid etching. Synthesis of the film consisting of titanium oxide pillar array structures was carried out using plasma-enhanced chemical vapor deposition equipment. The plasma was generated in a quartz vessel by an external SLAN-1 microwave source with a frequency of 2.45 GHz. Five specimens from each group were used (40 discs in total). On the surfaces to be studied, the following determinations were carried out: (a) X-ray photoelectron spectroscopy, (b) scanning electron microscopy, (c) energy dispersive X-ray spectroscopy, (d) profilometry, (e) contact angle measurement or surface wettability, (f) progression of contact angle on applying ultraviolet irradiation, and (g) a biocompatibility test and cytotoxicity with cell cultures. Results: The application of ultraviolet light decreased the hydrophobicity of all the surfaces studied, although it did so to a greater extent on the surfaces with the studied modification applied, this being more evident in samples manufactured in grade V titanium. In samples made in grade IV titanium, this difference was less evident, and even in the sample manufactured with grade IV and SLA treatment, the application of the nanometric modification of the surface made the surface optically less active. Regarding cell growth, all the surfaces studied, grouped in relation to the presence or not of the nanometric treatment, showed similar growth. Conclusions. Treatment of titanium oxide surfaces with ultraviolet irradiation made them change temporarily into superhydrophilic ones, which confirms that their biocompatibility could be improved in this way, or at least be maintained.

Microtomographic evaluation of a nanometric implant surface associated to L‐PRF: Study in osteoporotic rats

Background Osteoporosis is associated to decrease of bone mineral density, leading to an increase of skeletal frailty and fracture risk. Surface characteristics of dental implants may influence bone response, modulating cell proliferation and differentiation. Nanostructures applied to biomaterials may contribute to a higher bone to implant contact. Previous studies have shown that Leukocyte platelet rich fibrin (L-PRF) can increase the amount and formation rate of new bone around implants. Aim/Hypothesis To micro-tomographically evaluate, in osteoporotic rats, the bone repair around two implant surfaces, associated of not to L-PRF, analyzing Bone to Implant Contact (IS TS,%), Bone Volume Fraction (BV TV,%), Bone Surface Volume (BS BV,%) Trabecular Thickness (Tb.Th,mm), and Total Porosity (To.Po,%). Materials and Methods Mini implants with 2 types of surface (double acid etched=DAE, or with the addition of nano-hydroxyapatite = NHA + 24 implants of each type) were installed in the tibias of osteoporotic rats. In 24 rats, L-PRF was obtained with blood collection by means of cardiac puncture and posterior centrifugation, and inserted in the prepared bone site before implant insertion. The 48 rats were randomly divided into 4 experimental groups of 12 rats each- G1- DAE implants installed+ G2- NHA implants installed+ G3- DAE implants installed in association to L-PRF+ G4- NHA implants installed in association to L-PRF. All the mini implants were prepared for the study, measured 2.7 mm in length x 1.4 mm in diameter, and had the same macrostructure. The animals were euthanized 7 and 30 days (7d and 30d) after implants placement (6 from each group period). The tibias were removed for microtomographic evaluation of the bone between the threads of the implants, analyzing the previously described parameters. Results Inter-groups differences were assessed using One-way Analysis of Variance (P < 0.05 was considered). For IS TS, statistically significant differences were found in L-PRF treated rats between DAE (45.31 ± 5.06) versus NHA (52.81 ± 4.43) implants. For BV TV, there were statistically significant differences between G3 7d (44.08 ± 6.98) versus G4 7d (58.95 ± 5.53) and between G3 30d (54.33 ± 4.18) versus G4 30d (68.09 ± 6.56) + for the NHA surface, there were also statistical differences between rats without (49.57 ± 4.94) or with (63.52 ± 5.09) L-PRF treatment association. The results of BS BV showed statistically significant differences between DAE (36.71 ± 3.31) and NHA (32.13 ± 2.95) implant surfaces in L-PRF treated animals. For Tb.Th, there were statistically significant differences between G3 30d (0.093 ± 0.010) versus G4 30d (0.115 ± 0.012). For To.Po, statistically significant differences were found in L-PRF treated rats between DAE (53.69 ± 5.80) versus NHA (45.25 ± 4.98) implants. Conclusion and Clinical Implications Microtomographic analysis showed that the nano-hydroxyapatite implant surface presented more tridimensional bone to implant contact, bone volume fraction and trabecular thickness, and also less bone surface volume and porosity, when compared to DAE surface. Furthermore, the NHA surface was the most benefited by the association to L-PRF treatment. These results suggest that this treatment protocol (NHA + L-PRF) should be tested in humans, in trials evaluating challenging clinical situations.