Physicochemical, morphological, and biological analyses of Ti-15Mo alloy surface modified by laser beam irradiation.

Perform a physicochemical and morphological characterization of a Ti-15Mo alloy surface modified by laser beam irradiation and to evaluate in vitro the morphological response and proliferation of osteoblastic cells seeded onto this alloy. Disks were made of two different metals, Ti-15Mo alloy and cpTi, used as control. A total of four groups were evaluated: polished cpTi (cpTi-pol), laser-irradiated cpTi (cpTi-L), polished Ti-15Mo alloy (Ti-15Mo-pol), and laser-irradiated Ti-15Mo alloy (Ti-15Mo-L). Before and after laser irradiation of the surfaces, physicochemical and morphological analyses were performed: scanning electron microscopy (FEG-SEM), energy-dispersive spectroscopy (EDX), and X-ray diffraction (XRD). The wettability of the samples was evaluated by contact angle measurement. Murine preosteoblastic cells MC3T3-E1 were cultured onto the experimental disks for cell proliferation, morphology, and spreading analyses. Laser groups presented irregular-shaped cavities on its surface and a typical microstructured surface with large depressions (FEG-SEM). The contact angle for both laser groups was 0°, whereas for the polished groups was ≈ 77 and ≈ 78 for cpTi-pol and Ti-15Mo-pol, respectively. Cell proliferation analysis demonstrated a higher metabolic activity in the laser groups (p < 0.05). From the fluorescence microscopy, Ti-15Mo-L surface seems to induce greater cellular differentiation compared to the cpTi-L surface. The preliminary biological in vitro analyses suggested possible advantages of laser surface treatment in the Ti-15Mo alloy regarding cell proliferation and maturation.

Sol-gel based calcium phosphates coatings deposited on binary Ti-Mo alloys modified by laser beam irradiation for biomaterial/clinical applications.

Ti-15Mo alloy samples were irradiated by pulsed Yb: YAG laser beam under air and atmospheric pressure. Calcium phosphate coatings were deposited on the irradiated surfaces by the sol-gel method. The sol was prepared from the precursors Ca (NO3)2.4H2 O and H3 PO4. The modified surfaces were submitted to heat treatment conditions at 350 and 600 °C. The results showed that the two conditions established have a sufficient energy to promote ablation on the laser beam irradiated surfaces. Likewise, it has been demonstrated the processes of fusion and fast solidification from the laser beam irradiation, under ambient atmosphere, inducing the formation of stoichiometric TiO2 and non-stoichiometric titanium oxides, including Ti3O5, TiO, Ti3O and Ti6O with different oxide percentages depending on the fluency used. Besides that, laser modification has allowed a clean and reproducible process, providing no traces of contamination, an important feature for clinical applications. The physico-chemical and morphological properties indicated the formation of a mixture of phases: calcium pyrophosphate, hydroxyapatite and ß-TCP for the procedure (PA: calcination temperature), whereas HA (hydroxyapatite) and ß-TCP (tricalcium phosphate) were obtained by the procedure (PB: calcination temperature). Therefore, it was possible to obtain a Ti-15Mo alloy surface consisted on calcium phosphate ceramics of biological interest using the procedure (PB). Thus, the laser beam irradiation associated to bioactive coatings of calcium phosphates of biological interest have shown to be promising and economically feasible for use in dental and orthopedic implants.

Skeletal stem cell and bone implant interactions are enhanced by LASER titanium modification.

PURPOSE: To evaluate the osteo-regenerative potential of Titanium (Ti) modified by Light Amplification by Stimulated Emission of Radiation (LASER) beam (Yb-YAG) upon culture with human Skeletal Stem Cells (hSSCs(1)). METHODS: Human skeletal cell populations were isolated from the bone marrow of haematologically normal patients undergoing primary total hip replacement following appropriate consent. STRO-1(+) hSSC(1) function was examined for 10 days across four groups using Ti discs: i) machined Ti surface group in basal media (Mb(2)), ii) machined Ti surface group in osteogenic media (Mo(3)), iii) LASER-modified Ti group in basal media (Lb(4)) and, iv) LASER-modified Ti group in osteogenic media (Lo(5)). Molecular analysis and qRT-PCR as well as functional analysis including biochemistry (DNA, Alkaline Phosphatase (ALP(6)) specific activity), live/dead immunostaining (Cell Tracker Green (CTG(7))/Ethidium Homodimer-1 (EH-1(8))), and fluorescence staining (for vinculin and phalloidin) were undertaken. Inverted, confocal and Scanning Electron Microscopy (SEM) approaches were used to characterise cell adherence, proliferation, and phenotype. RESULTS: Enhanced cell spreading and morphological rearrangement, including focal adhesions were observed following culture of hSSCs(1) on LASER surfaces in both basal and osteogenic conditions. Biochemical analysis demonstrated enhanced ALP(6) specific activity on the hSSCs(1)-seeded on LASER-modified surface in basal culture media. Molecular analysis demonstrated enhanced ALP(6) and osteopontin expression on titanium LASER treated surfaces in basal conditions. SEM, inverted microscopy and confocal laser scanning microscopy confirmed extensive proliferation and migration of human bone marrow stromal cells on all surfaces evaluated. CONCLUSIONS: LASER-modified Ti surfaces modify the behaviour of hSSCs.(1) In particular, SSC(1) adhesion, osteogenic gene expression, cell morphology and cytoskeleton structure were affected. The current studies show Ti LASER modification can enhance the osseointegration between Ti and skeletal cells, with important implications for orthopaedic application.

Effect of surface treatment on the bond strength between yttria partially stabilized zirconia ceramics and resin cement.

STATEMENT OF PROBLEM: No consensus has been reached on the best bonding protocol between a zirconia ceramic surface and the tooth structure. PURPOSE: The purpose of this study was to evaluate the extrusion shear strength between yttria partially stabilized zirconia ceramics and resin cement (Panavia F) after different surface treatments. MATERIAL AND METHODS: The surface treatments evaluated (n=7) included the following: G1-control group (no surface treatment); G2-treated with MDP primer (Alloy Primer); G3-treated with 40% hydrofluoric acid (210 seconds); and G4-treated with 40% hydrofluoric acid (210 seconds) followed by MDP primer. The specimens were bonded to 2.5-mm-thick disks of bovine root dentin, and the extrusion shear tests were performed after they had been stored for 24 hours in distilled water at 37°C. The surface modifications were assessed on 2 specimens that were selected from each group by scanning electron microscopy. Data were analyzed with 1-way ANOVA and the Tukey-Kramer honestly significant difference test (α=.05). RESULTS: G4 (mean 2.84, standard deviation [SD] 0.43 MPa) presented significantly higher (P<.001) extrusion shear strength when compared with the other groups in the study (G1: mean, 1.57; SD 0.28 MPa; G2: mean 1.46, SD 0.28 MPa; G4: mean 1.16, SD 0.41 MPa). No significant differences were found among the other groups in the study. CONCLUSIONS: Yttria partially stabilized zirconia ceramics can be treated with 40% hydrofluoric acid for 210 seconds to increase the bond strength with the resin cement.

Commercially pure titanium implants with surfaces modified by laser beam with and without chemical deposition of apatite. Biomechanical and topographical analysis in rabbits.

OBJECTIVES: The purpose of this study was to evaluate the surfaces of commercially pure titanium (cp Ti) implants modified by laser beam (LS), without and with hydroxyapatite deposition by the biomimetic method (HAB), without (HAB) and with thermal treatment (HABT), and compare them with implants with surfaces modified by acid treatment (AS) and with machined surfaces (MS), employing topographical and biomechanics analysis. METHODS: Forty-five rabbits received 75 implants. After 30, 60, and 90 days, the implants were removed by reverse torque and the surfaces were topographically analyzed. RESULTS: At 30 days, statistically significant difference (P < 0.05) was observed among all the surfaces and the MS, between HAB/HABT and AS and between HAB and LS. At 60 days, the reverse torque of LS, HAB, HABT, and AS differed significantly from MS. At 90 days, difference was observed between HAB and MS. The microtopographic analysis revealed statistical difference between the roughness of LS, HAB, and HABT when compared with AS and MS. CONCLUSIONS: It was concluded that the implants LS, HAB, and HABT presented physicochemical and topographical properties superior to those of AS and MS and favored the osseointegration process in the shorter periods. In addition, HAB showed the best results when compared with other surfaces.

Surface and biomechanical study of titanium implants modified by laser with and without hydroxyapatite coating, in rabbits.

Surface and biomechanical analysis of titanium implant surfaces modified by laser beam with and without hydroxyapatite. Titanium implants with 3 different surfaces were inserted into the tibias of 30 rabbits: group I (GI) machined surface (control group), group II irradiated with laser (GII), and group III irradiated with laser and hydroxyapatite coating applied-biomimetic method (GIII). Topographical analysis with scanning electron microscopy was made before surgery in the tibia. These rabbits were distributed into 2 periods of observation: 4 and 8 weeks postsurgery, after which biomechanical analysis (removal torque) was conducted. Statistical analysis used the Student-Newman-Keuls method. Surface showed roughness in GII and GIII. Biomechanical analysis demonstrated values with significant differences in GII and GIII. Titanium implants modified by laser irradiation can increase osseointegration during the initial phase.

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 4 months, mandibular fixed implant prostheses were installed. Clinical and radiographic analyses were performed at times T0 (immediately after implant placement), T1 (15 days), T2 (30 days), T3 (60 days), T4 (90 days), T5 (120 days), T6 (180 days) and T7 (360 days), 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 (90 days), 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.

Biological performance of chemical hydroxyapatite coating associated with implant surface modification by laser beam: biomechanical study in rabbit tibias.

PURPOSE: Considering the potential of the association between laser ablation and smaller scale hydroxyapatite (HA) coatings to create a stable and bioactive surface on titanium dental implants, the aim of the present study was to determine, by the removal torque test, the effects of a surface treatment created by laser-ablation (Nd:YAG) and, later, thin deposition of HA particles by a chemical process, compared to implants with only laser-ablation and implants with machined surfaces. MATERIALS AND METHODS: Forty-eight rabbits received 1 implant by tibia of the following surfaces: machined surface (MS), laser-modified surface (LMS), and biomimetic hydroxiapatite coated surface (HA). After 4, 8, and 12 weeks of healing, the removal torque was measured by a torque gauge. The surfaces studied were analyzed according to their topography, chemical composition, and roughness. RESULTS: Average removal torque in each period was 23.28, 24.0, and 33.85 Ncm to MS, 33.0, 39.87, and 54.57 Ncm to LMS, and 55.42, 63.71 and 64.0 Ncm to HA. The difference was statistically significant (P < .05) between the LMS-MS and HA-MS surfaces in all periods of evaluation, and between LMS-HA to 4 and 8 weeks of healing. The surface characterization showed a deep, rough, and regular topography provided by the laser conditioning, that was followed by the HA coating. CONCLUSIONS: Based on these results, it was possible to conclude that the implants with laser surface modification associated with HA biomimetic coating can shorten the implant healing period by the increase of bone implant interaction during the first 2 months after implant placement.

Biomimetic apatite formation on Ultra-High Molecular Weight Polyethylene (UHMWPE) using modified biomimetic solution.

Modifications were performed on a biomimetic solution (SBF), according to previous knowledge on the behavior of ions present in its composition, in order to obtain apatite coatings onto Ultra-High Molecular Weight Polyethylene (UHMWPE) without having to use polymer pre-treatments that could compromise its properties. UHMWPE substrates were immersed into a 30% H(2)O(2) solution for a 24-h period and then submitted to a biomimetic coating method using standard SBF and two other modified SBF solutions. Apatite coatings were only obtained onto UHMWPE when the modified SBF solutions were used. Based on these results, apatite coatings of biological importance (calcium-deficient hydroxyapatite-CDHA, amorphous calcium phosphate-ACP, octacalcium phosphate-OCP, and carbonated HA) can be obtained onto UHMWPE substrates, allowing an adequate conciliation between bonelike mechanical properties and bioactivity.

Histometric analysis and topographic characterization of cp Ti implants with surfaces modified by laser with and without silica deposition.

Biologic behavior of the bone tissue around implants with four different surfaces was evaluated. The surfaces were: modified by laser (LS); modified by laser with sodium silicate deposition (SS); and commercially available surfaces modified by acid etching (AS) and machined surface (MS). Topographic characterization of the surfaces was performed by scanning electron microscopy (SEM)- energy dispersive X-ray spectrometry (EDX) before experimental surgery. Thirty rabbits received 60 implants in their right and left tibias, 1 implant of each surface being placed in each tibia. The analyzed periods were 4, 8, and 12 weeks postoperatively. Histometric analysis was performed evaluating bone interface contact (BIC) and bone area (BA). The results obtained were submitted to the analysis of variance and the Tukey t-test. The elemental mapping was evaluated by means of SEM at 4 weeks postoperatively. The topographic characterization showed differences between the analyzed surfaces. Generally, the BIC and BA of LS and SS implants were statistically higher than those of AS and MS in most of the analyzed periods. Elemental mapping showed high peaks of calcium and phosphorous in all groups. Based on the present methodology, it may be concluded that experimental modifications LS and SS accelerated the stages of the bone tissue repair process around the implants, providing the highest degree of osseointegration.

Nondecalcified histologic study of bone response to titanium implants topographically modified by laser with and without hydroxyapatite coating.

The purpose of this study was nondecalcified histologic analysis of titanium implants modified by laser with and without hydroxyapatite. Implants with three modified surfaces were inserted into rabbit tibias: group 1, machined surface; group 2, irradiated (laser); and group 3, irradiated and hydroxyapatite coated (biomimetic method). The mean surface roughness (Ra) scores of groups 2 and 3 were higher than that of group 1. Boneimplant contact measurements at 30 and 60 days for groups 2 and 3 were higher than for group 1. Bone area at 30 and 60 days for group 2 was higher than for groups 1 and 3. Titanium implants modified by laser with and without hydroxyapatite exhibit increased early osseointegration.

Biomedical Ti-Mo alloys with surface machined and modified by laser beam: biomechanical, histological, and histometric analysis in rabbits.

PURPOSE: In vivo bone response was assessed by removal torque, hystological and histometrical analysis on a recently developed biomedical Ti-15Mo alloy, after surface modification by laser beam irradiation, installed in the tibia of rabbits. MATERIALS AND METHODS: A total of 32 wide cylindrical Ti-15Mo dental implants were obtained (10mm × 3.75mm). The implants were divided into two groups: 1) control samples (Machined surface - MS) and 2) implants with their surface modified by Laser beam-irradiation (Test samples - LS). Six implants of each surface were used for removal torque test and 10 of each surface for histological and histometrical analysis. The implants were placed in the tibial metaphyses of rabbits. RESULTS: Average removal torque was 51.5Ncm to MS and >90Ncm to LS. Bone-to-implant-contact percentage was significantly higher for LS implants both in the cortical and marrow regions. CONCLUSIONS: The present study demonstrated that laser treated Ti-15Mo alloys are promising materials for biomedical application.

Implantes nanotopograficamente modificados pela ação do laser Yb-YAG / Nanofeatured dental implants by Yb-YAG laser modification

O titânio como biomaterial apresenta excelente biocompatibilidade e resistência à corrosão. Vários estudos foram realizados nas últimas décadas sobre modificação da superfície dos implantes de titânio, a fim de otimizar o processo da osseointegração; o uso do laser é um dentre eles. Objetivo: o propósito deste estudo foi avaliar implantes de titânio modificados por feixe de laser de alta intensidade, comparando-os com os implantes usinados, por meio de análise topográfica e histométrica. Métodos: implantes de titânio com duas superfícies diferentes foram inseridas em tíbia de 30 coelhos (um de cada lado, escolhidos de forma aleatória). Grupo I (GI) superfície usinada (grupo controle) e Grupo II (GII) superfície irradiada com laser Yb-YAG (Pulsed Ytterbium Fiber Laser). A caracterização das superfícies foi realizada por meio de MEV-EDS, ângulo de contato e rugosidade média (Ra). Após 30 e 60 dias pós-operatórios, os animais foram submetidos à eutanásia e os implantes foram removidos para análise histológica da interface osso/implante. Resultados: a microfotografia do GII mostrou superfície rugosa e homogênea, com molhabilidade total e rugosidade maior do que o GI. A análise histológica da extensão linear de contato entre o tecido ósseo e a superfície do implante (Elcoi) revelou melhores resultados no GII aos 30 dias (39,26 ± 18,23 e 68,41 ± 13,68, para GI e GII, respectivamente). Conclusão: os implantes de titânio modificados por laser mostraram importantes características superficiais que favoreceram uma precoce osseointegração.

Titanium has proven its suitability as an implant material in surgery over many years. Excellent biocompatibility and corrosion resistance are outstanding features. Implant surfaces always causes concern and interest in scientific communities, due to its close relationship with the time required for osseointegration. Surface modification can be performed by several methods, being laser irradiation one of them. Titanium implants with two different surfaces were inserted in rabbits: Group I (G-I: machined surface, control group), and group II (G-II: laser irradiated, test group) being processed 30 and 60 days after surgery for histological analysis. Surface characterization was performed with SEM-EDS, contact angle measurement, and mean roughness (Ra) parameters. Surface analysis in the GII group showed a nanomorphology affected by melt and quick solidification zones following laser irradiation (SEM), as well as total wettability and Ra mean values significantly higher than in the G-I group. The laser treatment resulted in a homogenized, porous surface, with increased surface area and volume. Histological analysis of bone-implant contact linear extension (BIC) showed better results in G-II at 30 days (39.26 ± 18.23 and 68.41 ± 13.68 for G-I and G-II groups, respectively). Titanium implants modified by laser irradiation showed important features that may accelerate early osseointegration.