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1.
J Contemp Dent Pract ; 21(6): 636-639, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33025932

RESUMO

AIM: Variation in the surface roughness of archwires not only leads to more accumulation of plaque but also modifies the coefficient of friction. This necessitated for the present study to evaluate the surface characteristics of 0.016 × 0.022-inch nickel-titanium, beta-titanium, and copper-nickel-titanium archwires, before and after their use in the oral cavity using atomic force microscopy. MATERIALS AND METHODS: The control and experimental samples were measured at three different positions under atomic force microscopy. The surface roughness was measured using roughness average, root mean square, and maximum height before and after use in the oral cavity among 60 adult participants. Data were analyzed using a one-way analysis of variance and Student's t tests using the Statistical Package for Social Software (SPSS) v.20.0. RESULTS: The surface roughness of archwires increased considerably after their clinical use compared to controls for nickel-titanium (p = 0.013) and beta-titanium (p = 0.002). A similar trend was noticed for root mean square where nickel-titanium (p = 0.014) and beta-titanium (p = 0.013) had increased root mean square. Maximum height was also noticed in nickel-titanium (p = 0.031) and beta-titanium (p = 0.016). CONCLUSION: Surface roughness and the level of friction of the orthodontic wires increase significantly for nickel-titanium and beta-titanium after the clinical use. There is a difference in increase of surface roughness of the archwire within and between the bracket slots. CLINICAL SIGNIFICANCE: Nickel-titanium and beta-titanium wires show more roughness and resultant higher friction levels after use in the oral cavity. Hence, care related to plaque accumulation is essential.


Assuntos
Cobre , Níquel , Ligas Dentárias , Humanos , Teste de Materiais , Propriedades de Superfície , Titânio
2.
J Contemp Dent Pract ; 21(7): 728-732, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33020354

RESUMO

AIM: The aim of the present study is twofold: to evaluate cyclic fatigue resistance differences of two different nickel-titanium rotary instruments, brand new and after an ex vivo instrumentation of single root extracted teeth. MATERIALS AND METHODS: Twenty new S One 20.06 were randomly divided into two groups. The first group (n = 10) was immediately subjected to a cyclic fatigue test (S One Group I). The second group (n = 10) (S one Group II) performed a cyclic fatigue test after three ex vivo root canal treatment with a single-file technique. The same process has been carried out for 20 M-Two 20.06 instruments. RESULTS: Mean time to fracture (TtF) for Group I was 51.14 ± 1.28 for S One and 32.62 ± 0.17 for M-Two 20.06 and for Group II was 46.00 ± 0.99 for S One and 27.75 ± 1.58 for M-Two 20.06. The reduction in TtF values from Group I to Group II was 11% for S One and 15% for M-Two. Statistical analysis found significant differences in all the groups examined (p value < 0.05). Mean fragment length (FL) for Group I was 3.07 ± 0.17 for S One and 3.05 ± 0.14 for M-Two 20.06 and for Group II was 3.05 ± 0.07 for S One and 3.05 ± 0.14 for M-Two 20.06. Statistical analysis was pursued, and no significant difference was found (p value > 0.05). CONCLUSION: The S-One showed significantly more resistance to cyclic fatigue stress than M-Two for both new and used instruments. This validates the hypothesis that the AF H wire enables the S One files to endure more the cyclic fatigue stresses. CLINICAL SIGNIFICANCE: This study demonstrates the cyclic fatigue resistance of a new endodontic instrument after repetitive usage.


Assuntos
Níquel , Titânio , Cavidade Pulpar , Desenho de Equipamento , Falha de Equipamento , Teste de Materiais , Preparo de Canal Radicular
3.
Stomatologiia (Mosk) ; 99(5): 7-10, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33034170

RESUMO

BACKGROUND: The adhesion ability of microorganisms to the surface of titanium miniplates and screws is one of factors in the development of purulent-inflammatory complications in the postoperative period. One of the solutions to this problem is the use of an ion-plasma coating of mini-plates and screws. OBJECTIVE: The aim of the study was to prove a decrease adhesion level of pathogenic and conditionally pathogenic bacterium to samples of titanium mini-plates with ion-plasma coating, compared with samples without coating. MATERIAL AND METHODS: Present opinion about microbial adhesion, how the most important stage of development microbial colonization of abiotic surfaces, was been basis of this study. The strains of aerobic and facultative anaerobic pathogens, as well as the non-spore-forming (non-clostridial) obligate-anaerobic pathogens were used in the research. During the experiments the standard method for determining residual adhesion was applied. The data obtained were processed by the «Biostat 9.0¼ software package. For the data received by the methods of variational parametric and nonparametric statistics we used the Mann-Whitney test, taking into account the average value, error, and the number of observations (significance of differences at p<0.05). RESULTS: As a result, the differences between the indices residual adhesion of strains aerobic and facultative anaerobic pathogens on the samples with and without a protective coating were statistically reliable, however, the adhesion of the individual species varied. The same differences between the indices residual adhesion were obtained among the strains of obligate anaerobic pathogens. The low level of adhesion, which was observed in the case of using the protective coating, is a very promising way of development, since these microorganisms are dangerous as the may lead to the development of purulent-inflammatory complications and the rejection of implants. CONCLUSION: The decreased level of adhesion is a factor which reduces the microbial load during the postoperative period.


Assuntos
Aderência Bacteriana , Titânio , Ossos Faciais , Propriedades de Superfície
4.
Shanghai Kou Qiang Yi Xue ; 29(3): 250-256, 2020 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-33043340

RESUMO

PURPOSE: To compare the mechanical properties of 3D-printed titanium meshes and pre-shaped titanium meshes, and to evaluate the effects of 3D-printed titanium meshes on cell proliferation and differentiation. METHODS: 3D- printed titanium meshes were produced and prepared with laser printing machine. The mechanical properties were analyzed by static tension and compression load test. Bone marrow mesenchymal stem cells (BMSCs) were extracted from 4-week-old male SD rats. BMSCs were co-cultured with 3D-printed titanium meshes of different apertures. Cell counting kit-8 (CCK-8) assay was used to detect cell proliferation. Alkaline phosphatase (ALP) activity assay was used to test ALP activity. The expression of related osteogenic genes was tested by real-time PCR. The adhesion and growth of BMSCs were investigated by scanning electron microscopy (SEM) and living / dead cell staining. SPSS 22.0 software package was used for statistical analysis of the results. RESULTS: The results of 3D-printing Ti-meshes tension and compression loading experiment were excellent. The 3D-printing Ti-meshes showed no inhibitory effects on cell proliferation, survival and adhesion, but had a positive effect on osteogenesis of BMSCs. CONCLUSIONS: The mechanical properties of 3D-printed Ti-meshes are excellent. The 3D-printed Ti-meshes have good biocompatibility.


Assuntos
Implantes Dentários , Titânio , Animais , Masculino , Impressão Tridimensional , Ratos , Ratos Sprague-Dawley , Telas Cirúrgicas
5.
Shanghai Kou Qiang Yi Xue ; 29(3): 333-336, 2020 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-33043356

RESUMO

PURPOSE: To investigate the value of internal fixation in management of mandibular comminuted fracture with mini-titanium plate. METHODS: Twenty-one patients with mandibular comminuted fracture treated in Stomatology Hospital of Shenyang from March 2017 to February 2018 were enrolled, the patients received internal fixation with mini-titanium plate. The lower mandibular margin, upper mandibular margin and middle outer cortex were fixed respectively. The postoperative fracture healing and adverse reactions were recorded and analyzed. RESULTS: All patients achieved bone healing within 3 months after surgery, with an average duration of (1.53±0.36) months. Among 21 patients, six patients (28.57%) had minimal occlusion, and 1 patient (4.76%) had local infection. No microtitanium plate fracture, persistent pain, limited mouth opening, tooth injury, facial nerve injury or nonunion were found. CONCLUSIONS: Internal fixation with mini-titanium for comminuted mandibular fracture patients without bone defects has the advantages of good postoperative fracture healing, short healing time and few adverse reactions.


Assuntos
Fraturas Cominutivas , Fraturas Mandibulares , Fraturas Cominutivas/diagnóstico por imagem , Fraturas Cominutivas/cirurgia , Humanos , Mandíbula , Fraturas Mandibulares/diagnóstico por imagem , Fraturas Mandibulares/cirurgia , Estudos Retrospectivos , Titânio
6.
Int J Oral Maxillofac Implants ; 35(5): 888-899, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991638

RESUMO

PURPOSE: The aim of this study was to evaluate the formed biofilm on two types of implant surfaces (hydrophilic or hydrophobic) associated with titanium (Ti) or zirconia (Zn) abutments. MATERIALS AND METHODS: Samples were separated into four groups according to type of surface and abutment used (n = 10): (1) hydrophobic/Ti abutment, (2) hydrophilic/Ti abutment, (3) hydrophobic/Zn abutment, and (4) hydrophilic/Zn abutment. Implant-abutment assemblies were incubated with human saliva and supragingival biofilm. Samples of biofilm were evaluated by DNA Checkerboard hybridization, identifying up to 41 species. Scanning electron microscopy (SEM) images were obtained from the implants and abutments. RESULTS: The microbial count was higher for samples from groups with the hydrophilic/Ti abutment, followed by hydrophobic/Zn abutment, hydrophilic/Ti abutment, and hydrophobic/Zn abutment (P < .05). Hydrophilic surfaces and Zn abutments showed the highest counts of microorganisms. Individual bacterial counts were variable between groups; the hydrophilic/Zn abutment group had the highest microbial diversity, including T forsythia, P nigrescens, S oralis, S sanguinis, L casei, M orale, P aeruginosa, P endodontalis, S aureus, S gallolyticus, S mutans, S parasanguinis, S pneumoniae, and C albicans. The hydrophilic/Ti abutment group had the highest count of T forsythia and T denticola, microorganisms of Socransky red complex. The SEM images showed the bacterial colonization in both surfaces of the implant and abutment. CONCLUSION: Different surfaces of implants and abutments showed significant differences in the count and diversity of species. The hydrophilic/Zn abutment group presented the highest count and diversity of target species.


Assuntos
Implantes Dentários , Titânio , Biofilmes , Projeto do Implante Dentário-Pivô , Genômica , Humanos , Teste de Materiais , Zircônio
7.
Int J Oral Maxillofac Implants ; 35(5): 939-947, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991644

RESUMO

PURPOSE: This study investigated the effects of bisphosphonates, namely, alendronate and zoledronate, on the osteogenic activity of osteoprogenitor cells cultured on titanium surfaces at therapeutic doses in order to assess if altered osteoblastogenesis could compromise osseointegration and contribute to etiopathogenesis of painful disorders such as bisphosphonates-related osteonecrosis of the jaw (BRONJ) following implant placement. MATERIALS AND METHODS: MC3T3-E1 Subclone 4 cells were utilized in this study. Therapeutic doses of alendronate and zoledronate were calculated based on reported peak plasma concentrations. The viability, proliferation, adhesion, and mineralization potential of cells was assessed using a LIVE/DEAD stain, alamarBlue assay, immunofluorescence microscopy, and Alizarin Red S staining, respectively. RESULTS: Therapeutic doses of zoledronate negatively affected cell viability, whereas therapeutic doses of alendronate significantly enhanced cell differentiation and the amount of bone formation compared with the control. CONCLUSION: The findings of this study may provide some insight into the pathogenesis of BRONJ development following implant placement in patients treated with zoledronate and may have promising implications toward improved wound healing and osseointegration in patients treated with alendronate.


Assuntos
Difosfonatos/efeitos adversos , Osteogênese , Alendronato , Células Cultivadas , Humanos , Titânio
8.
Int J Oral Maxillofac Implants ; 35(5): 948-954, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991645

RESUMO

PURPOSE: The aim of this study was to compare the effect of different surface treatments applied to short titanium and zirconia abutments on the bond strength of single-unit zirconia crowns. MATERIALS AND METHODS: Sixty titanium abutments were shortened to 3 mm in length, fixed to analogs, and embedded in acrylic blocks. Three-dimensional views of abutments were obtained by scanning; then, zirconia abutments and copings were produced. The samples, which included titanium (n = 60) and zirconia (n = 60) abutments, were divided into five different groups (n = 12), and surface treatments were carried out; 1.5-W and 3-W Er,Cr:YSGG laser treatment, AL2O3 sandblasting, and tribochemical silica coating were applied to the groups, and the control group had no surface treatment. Copings were cemented to the samples with self-adhesive resin cement. The samples were then subjected to the pull-out test, and the results were processed via statistical analysis. RESULTS: There was a significant difference between the titanium and zirconia groups (P < .001). The mean bond strength values of the titanium samples were higher than those of the zirconia samples. The tribochemical silica coating gave a higher bond strength than the other treatments when applied to titanium abutments. For the zirconia abutments, the 1.5-W laser treatment, 3-W laser treatment, tribochemical silica coating, and Al2O3 sandblasting groups differed significantly from the control group; however, they were not significantly different from each other. CONCLUSION: The bond strength of zirconia crowns to short titanium and zirconia abutments increases with surface treatments. Furthermore, the surface treatments were more effective in increasing the bond strength for the titanium abutments than for the zirconia abutments.


Assuntos
Titânio , Zircônio , Coroas , Propriedades de Superfície
9.
Int J Oral Maxillofac Implants ; 35(5): 1013-1020, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991653

RESUMO

PURPOSE: The hydrophilic implant surface (INICELL) is a chemical alteration of a sandblasted and thermally acid-etched surface that should lead to long-term osseointegration. This study investigated 3-year results after early loading of implants with a hydrophilic, moderately rough surface in occlusal contact. MATERIALS AND METHODS: This prospective case series study was conducted in subjects with partially edentulous mandibles. Implants were placed on day 21 and loaded with a provisional reconstruction after at least 21 days of healing (baseline, day 0) if their implant stability quotient (ISQ) was ≥ 70 (mean of three measurements) and were replaced by definitive porcelain-fused-to-metal prostheses at the 6-month follow-up visit. Follow-up examinations were planned 1, 3, 6, 12, and 36 months after baseline. RESULTS: A total of 20 implants were placed in 15 patients (mean age: 51 years, range: 32 to 67 years). After 36 months, all implants were osseointegrated, and no suppuration was recorded. Small changes of bone level were observed between 3 months and 36 months. At 36 months, the median values of the 20 implants were 0.25 (range: 0 to 0.5, SD: 0.17), 0.25 (range: 0 to 1, SD: 0.27), and 4 (range: 2 to 7.25, SD: 1.17) for the mean modified Plaque Index (mPI), mean modified Sulcus Bleeding Index (mSBI), and mean probing pocket depth, respectively. The pairwise analysis between 3 and 36 months showed an improvement in the mean mPI (P = .0126) and mean mSBI (P = .0059). After 36 months, all patients (n = 15) were fully satisfied with a mean of 9.43 (range: 8 to 10, SD: 0.678) at the visual analog scale. CONCLUSION: Early functional loading of implants with a hydrophilic, moderately rough outer surface in occlusal contact 21 days after healing appears to be a safe and feasible treatment option when placed in the posterior mandible of partially edentulous patients.


Assuntos
Implantes Dentários , Titânio , Adulto , Idoso , Humanos , Mandíbula , Pessoa de Meia-Idade , Osseointegração , Estudos Prospectivos
10.
Cent Eur J Public Health ; 28(3): 202-207, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32997476

RESUMO

OBJECTIVE: Nanomaterials consist of particles smaller than 100 nm - nanoparticles (NPs). Their nano dimensions allow them to penetrate through various membranes and enter into the bloodstream and disseminate into different body organs. Massive expansion of nanotechnologies together with production of new nanoparticles which have not yet been in contact with living organisms may pose a potential health problem. It is therefore necessary to investigate the health impact of NPs after experimental exposure. Comparison of the effect of TiO2 and NPs Fe3O4 in Wistar rats at time intervals 1, 7, 14 and 28 days was performed by studying the cytotoxic effect in the isolated inflammatory cells from bronchoalveolar lavage (BAL). METHODS: Wistar rats were intravenously (i.v.) given a suspension of NPs TiO2 or Fe3O4 (coated by sodium oleate) via the tail vein. After time intervals of 1, 7, 14 and 28 days, we sacrificed the animals under anaesthesia, performed BAL and isolated the cells. The number of animals in the individual groups was 7-8. We examined the differential count of BAL cells (alveolar macrophages - AM, polymorphonuclear leukocytes - PMN, lymphocytes - Ly); viability and phagocytic activity of AM; the proportion of immature and polynuclear cells and enzymes - cathepsin D - CAT D, lactate dehydrogenase - LDH and acid phosphatase - ACP. RESULTS: We found that TiO2 NPs are relatively inert - without induction of inflammatory and cytotoxic response. Exposure to nanoparticles Fe3O4 induced - under the same experimental conditions - in comparison with the control and TiO2 a more extensive inflammatory and cytotoxic response, albeit only at 1, 7 and 14 days after injection. CONCLUSIONS: The results suggest that TiO2 and Fe3O4 nanoparticles used in our study were transferred from the bloodstream to the respiratory tract, but this effect was not observed at 28 days after i.v. injection, probably due to their removal from the respiratory tract.


Assuntos
Óxido Ferroso-Férrico/toxicidade , Nanopartículas Metálicas/toxicidade , Doenças Respiratórias/induzido quimicamente , Titânio/toxicidade , Administração Intravenosa , Animais , Óxido Ferroso-Férrico/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Ratos , Ratos Wistar , Titânio/administração & dosagem
11.
Braz Dent J ; 31(4): 374-379, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32901712

RESUMO

The aim of this study was to verify the effect of the implant volume loss, vertical misfit between abutment and prosthetic platform, prosthetic screw loosening torque, and screw stress distribution in titanium and zirconia abutments. Ten CAD/CAM system custom abutments of each material were milled and attached to the titanium implants. The implant volume loss was evaluated by microtomography, the vertical misfit with optical microscopy, and digital torque wrench measured the prosthetic screw loosening. All experimental analyses were performed before and after mechanical cycle (1,000,000 cycles, 100 N/2 Hz). Virtual models of the structures were created for finite element analysis, and the stress on the screw obtained with von Mises procedure. Data were analyzed using an independent t-test, two-way ANOVA for repeated measures, and Tukey's HSD test (a=0.05). There was no significant difference in the implant volume loss for the two abutment materials (p=0.662). Titanium abutments provided higher loosening torque values after mechanical cycling (p<0.001). Lesser marginal misfit was obtained with titanium abutments before and after mechanical cycling (p<0.001). The stress distribution on the screw was similar between abutment materials. In conclusion, CAD/CAM custom titanium abutment reduced the marginal misfit and increased the torque maintenance of prosthetic screws when compared to CAD/CAM custom zirconia abutment.


Assuntos
Dente Suporte , Titânio , Parafusos Ósseos , Zircônio
12.
Braz Dent J ; 31(4): 380-384, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32901713

RESUMO

The purpose of this study was to compare biofilm formation on materials used for the fabrication of implant-supported dental prostheses. Twenty discs (D=15 mm, H=3 mm) were fabricated from one of the following restorative materials: yttria tetragonal zirconia polycrystal (Y-TZP); commercially pure titanium (CP-Ti); or heat-cured polymethyl methacrylate (PMMA). Specimens were polished following standard protocols. A non-contact profilometer (NPFLEX, Bruker, UK) was used to assess the surface roughness of each disk; results were reported as Ra (µm). Five strains of Gram-negative bacteria frequently associated with peri-implantitis, Aggregatibacter actinomycetemcomitans, Candida. albicans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythia, were cultured on hand-polished discs fabricated from heat-cured PMMA, Y-TZP, or CP-Ti to compare biofilm formation on each type of material. The results were reported as colony-forming units per milliliter (CFU/mL). One-way ANOVA and post hoc tests were used to compare surface roughness and bacterial colonization on the respective materials. Statistical significance was set at a = 0.05. Discs fabricated from Y-TZP had a significantly higher Ra value (350 ± 30 µm) than either PMMA, or CP-Ti discs. Discs fabricated from either Y-TZP and CP-Ti may exhibit less colonization by bacteria associated with peri-mucositis and peri-implantitis. Y-TZP and CP-Ti are suggested materials for fabrication of implant-supported prostheses, considering biofilm formation.


Assuntos
Implantes Dentários , Peri-Implantite , Biofilmes , Humanos , Propriedades de Superfície , Titânio
13.
Braz Dent J ; 31(4): 423-430, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32901720

RESUMO

The aim of this study was to assess the effect of a newly developed nanocomplex formed of hydroxypropyl-b-cyclodextrin and 1% titanium tetrafluoride (TiF4) after distinct complexation periods (12/72 h) on demineralization of bovine enamel in vitro. Enamel blocks (n=60) were allocated in different groups: Mili-Q water, hydroxypropyl-b-cyclodextrin, 1% TiF4, hydroxypropyl-b-cyclodextrin + 1% TiF4 after 12 h of complexation and hydroxypropyl-b-cyclodextrin + 1% TiF4 after 72 h of complexation. The samples were evaluated by surface microhardness, cross-sectional microhardness and micro-CT. Scanning electron microscopy and energy dispersive X-ray spectrometry (SEM/EDX) were also obtained. Hydroxypropyl-b-cyclodextrin + 1% TiF4 after 12 h complexation resulted in lower percentage of surface microhardness loss compared to Mili-Q water, hydroxypropyl-b-cyclodextrin, 1% TiF4 and hydroxypropyl-b-cyclodextrin + 1% TiF4 after 72 h of complexation group, with a large effect size (from 1.307 to 2.943) and high power (84.9 to 99%). All groups resulted in similar integrated mineral loss (ΔZ) obtained by both internal microhardness and micro-CT techniques. Enamel treated with TiF4 and TiF4 + hydroxypropyl-b-cyclodextrin groups showed a TiO2 glaze-layer, while EDX evaluation identified Ti. The solution containing the inclusion complex of hydroxypropyl-b-cyclodextrin + TiF4 with 12 h of complexation period demonstrated a significant ability to reduce surface demineralization of sound enamel under an artificial cariogenic challenge.


Assuntos
Ciclodextrinas , Fluoretos , Animais , Bovinos , Estudos Transversais , Esmalte Dentário , Titânio
14.
Sci Total Environ ; 741: 140394, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32886989

RESUMO

The photocatalytic activity of two bio-based polymer photocatalysts [poly(ethylene terephthalate)-TiO2 (PET-TiO2) and poly(L-lactic acid)-graphene oxide-TiO2 (PLLA-GO-TiO2)] towards Tamoxifen (TAM), Cyclophosphamide (CP), Cytarabine (CYT) and 5-Fluorouracil (5-FLU) removal was explored and compared. The highest photocatalytic activity for the degradation of the cytostatic drugs was accomplished by PET-TiO2. Among the contaminants, TAM was the most easily removed, requiring 90 min for complete elimination, while CP showed the highest resistance to photocatalysis, not being completely removed after 6 h. Liquid chromatography coupled with high-resolution mass spectrometry analysis was employed for the identification of several transformation products (TPs) and potential pathways were proposed. A total of seventy (70) TPs including thirty-four (34) novel ones detected in AOPs were identified. The ecotoxicity of the mixture of the cytostatic drugs and TPs formed during the photocatalytic treatment was evaluated using Daphnia magna assay and was associated with the occurrence of specific TPs during the treatment process. The follow-up ECOSAR (Ecological Structure Activity Relationship) analysis further elucidated that only minor chemical transformations, such as the hydroxylation or the oxidative opening of an aromatic ring system, could hamper the adverse effects of cytostatic drugs in aquatic species. Such a comparative study on the mixture toxicity of cytostatics and their TPs is presented for the first time.


Assuntos
Citostáticos , Poluentes Químicos da Água/análise , Animais , Catálise , Ciclofosfamida , Fotólise , Titânio
15.
Water Sci Technol ; 82(4): 695-703, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32970622

RESUMO

The current work investigates the removal of two hazardous macrolide molecules, spiramycin and tylosin, by photodegradation under external UV-light irradiation conditions in a slurry photoreactor using titanium dioxide as a catalyst. The kinetics of degradation and effects of main process parameters such as catalyst dosage, initial macrolide concentration, light intensity and stirring rate on the degradation rate of pollutants have been examined in detail in order to obtain the optimum operational conditions. It was found that the process followed a pseudo first-order kinetics according to the Langmuir-Hinshelwood model. The optimum conditions for the degradation of spiramycin and tylosin were low compound concentration, 1 g L-1 of catalyst dosage, 100 W m-2 light intensity and 560 rpm stirring rate. Then, a maximum removal (more than 90%) was obtained after 300 min of irradiation time. Furthermore, results show that the selection of optimized operational parameters leads to satisfactory total organic carbon removal rate (up to 51%) and biochemical oxygen demand to chemical oxygen demand ratio (∼1) confirming the good potential of this technique to remove complex macrolides from aqueous solutions.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Catálise , Cinética , Macrolídeos , Fotólise , Titânio , Raios Ultravioleta
16.
Dental Press J Orthod ; 25(4): 51-58, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32965387

RESUMO

OBJECTIVE: To investigate the effect of ZnO nanocoating on mechanical properties of NiTi orthodontic wires and antibacterial activity. METHODS: 0.016 x 0.022-in NiTi orthodontic wires were coated with ZnO nanoparticles using an electrochemical deposition method with three electrodes system in 0.1M Zn(NO3)2. Mechanical properties and frictional resistance of the coated wires were investigated using an universal testing machine. Antibacterial effect of ZnO coating was also investigated. RESULTS: A stable adhered ZnO nanocoating on NiTi wires was obtained. The coated wires have a significant antibacterial activity against S. aureus, S. pyogens and E. coli, and a reduction of frictional forces by 34%. CONCLUSION: ZnO nanocoating may improve the antibacterial effects of NiTi wires and reduce the frictional resistance. Coating may be implanted in orthodontic practice for faster and safer treatment.


Assuntos
Óxido de Zinco/farmacologia , Antibacterianos/farmacologia , Ligas Dentárias , Escherichia coli , Teste de Materiais , Níquel , Fios Ortodônticos , Staphylococcus aureus , Propriedades de Superfície , Titânio/farmacologia , Zinco
17.
Nat Commun ; 11(1): 4465, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901012

RESUMO

Titanium implants have been widely used in bone tissue engineering for decades. However, orthopedic implant-associated infections increase the risk of implant failure and even lead to amputation in severe cases. Although TiO2 has photocatalytic activity to produce reactive oxygen species (ROS), the recombination of generated electrons and holes limits its antibacterial ability. Here, we describe a graphdiyne (GDY) composite TiO2 nanofiber that combats implant infections through enhanced photocatalysis and prolonged antibacterial ability. In addition, GDY-modified TiO2 nanofibers exert superior biocompatibility and osteoinductive abilities for cell adhesion and differentiation, thus contributing to the bone tissue regeneration process in drug-resistant bacteria-induced implant infection.


Assuntos
Antibacterianos/química , Grafite , Nanofibras/química , Próteses e Implantes , Infecções Relacionadas à Prótese/prevenção & controle , Titânio , Células 3T3 , Animais , Materiais Biocompatíveis/química , Regeneração Óssea , Sobrevivência Celular , Modelos Animais de Doenças , Feminino , Teste de Materiais , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Nanocompostos/química , Osteogênese , Processos Fotoquímicos , Infecções Estafilocócicas/prevenção & controle
18.
Int J Prosthodont ; 33(5): 527-535, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956434

RESUMO

PURPOSE: To establish the most effective cementation protocol for bonding zirconia crowns to Ti-Base CAD/CAM abutments in terms of abutment height, cement type, and surface pretreatment. MATERIALS AND METHODS: Zirconia crowns were designed to fit abutments of 2.5-mm (short) and 4.0-mm (tall) height. The retention of conventional resin cement with a universal adhesive (RelyX Ultimate, 3M ESPE) was compared to self-adhesive resin cement (RelyX U200, 3M ESPE) following different surface pretreatments (n = 10/group): (1) no treatment (NT); (2) Ti-Base abutment surface blasting with alumina particles (SB); (3) zirconia crown tribochemical surface blasting with silica-coated alumina particles (TBS); and (4) a combination of SB + TBS. Pull-out testing was performed in a universal testing machine. Data were statistically evaluated using a linear mixed model following least significant difference post hoc test. RESULTS: Pull-out data as a function of Ti-Base height demonstrated higher retention for tall compared to short abutments (P < .001). Ultimate outperformed U200 cement (data collapsed over height and pretreatment) (P < .001). Analysis of pretreatment depicted higher retention for SB + TBS, followed by SB, TBS, and NT (P < .04). The interaction between Ti-Base height and cement type highlighted the superior adhesive strength of Ultimate compared to U200 for both heights (P < .001). Irrespective of type of pretreatment, surface pretreatment improved the retention for U200 cement and short Ti-Base (P < .03 compared to NT). In contrast, higher retention was demonstrated for SB + TBS, followed by SB, TBS, and NT, for Ultimate cement combined with tall Ti-Base (P < .02) (data collapsed over height and cement, respectively). CONCLUSION: There was a direct relationship among Ti-Base height, micromechanical and/or chemical pretreatment, and conventional adhesive bonding in improving the retention of zirconia crowns.


Assuntos
Cimentação , Titânio , Desenho Assistido por Computador , Coroas , Dente Suporte , Análise do Estresse Dentário , Teste de Materiais , Cimentos de Resina , Zircônio
19.
Int J Prosthodont ; 33(5): 546-552, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956436

RESUMO

PURPOSE: To evaluate the effect of cementation protocols on the bonding interface stability and pull-out forces of temporary implant-supported crowns bonded on a titanium base abutment (TiB) or on a temporary titanium abutment (TiA). MATERIALS AND METHODS: A total of 60 implants were restored with PMMA-based CAD/CAM crowns. Five groups (n = 12) were created: Group 1 = TiB/SRc: crown conditioned with MMA-based liquid (SR Connect, Ivoclar Vivadent); Group 2 = TiB/50Al-MB: crown airborne particle-abraded with 50-µm Al2O3 and silanized (Monobond Plus, Ivoclar Vivadent); Group 3 = TiB/30SiOAl-SRc: crown airborne particle-abraded with 30-µm silica-coated Al2O3 (CoJet, 3M ESPE) and conditioned with MMA-based liquid (SR Connect); Group 4 = TiB/30SiOAl-MB: crown airborne particle-abraded with 30- µm silica-coated Al2O3 (CoJet) and silanized (Monobond Plus); and Group 5 = TiA/TA-PMMA: crown manually enlarged, activated, and rebased with PMMA resin (Telio Lab, Ivoclar Vivadent). Specimens in the TiB groups were cemented using a resin cement (Multilink Hybrid Abutment, Ivoclar Vivadent). After aging (120,000 cycles, 49 N, 1.67 Hz, 5°C to 55°C, 120 seconds), bonding interface failure was analyzed (50x). Pull-out forces (N) (0.5 mm/minute) and modes of failure were registered. Chi-square and Kruskal-Wallis tests were used to analyze the data (α = .05). RESULTS: Bonding failure after aging varied from 0% (Group 5) to 100% (Groups 1, 2, and 4) (P < .001). Mean pull-out force ranged between 53.1 N (Group 1) and 1,146.5 N (Group 5). The pull-off forces were significantly greater for Group 5 (P < .05), followed by Group 3 (P < .05), whereas the differences among the remaining groups were not significant (P > .05). CONCLUSION: The cementation protocol had an effect on the bonding interface stability and pull-out forces of PMMA-based crowns bonded on a titanium base. Airborne particle abrasion of the crown internal surface and conditioning it with an MMA-based liquid may be recommended to improve retention of titanium base temporary restorations. Yet, for optimal outcomes, conventional temporary abutments might be preferred.


Assuntos
Implantes Dentários , Titânio , Desenho Assistido por Computador , Coroas , Dente Suporte , Análise do Estresse Dentário , Teste de Materiais , Cimentos de Resina , Zircônio
20.
Chemosphere ; 254: 126794, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957267

RESUMO

Present study carried out pot experiments and evaluated effects of single and binary mixture of nanoparticles (exposed via sludge as soil conditioner) on spinach plant. Exposure of Ag2O nanoparticles (NPs) (1 and 10 mg/kg soil-sludge) did not show significant reduction in plant as compared to control. On the other hand, TiO2 NPs (exposed as single and in binary mixture) resulted in significant increase in root length (29% and 37%) and fresh weight (60% and 48%) at highest exposure concentration. Total chlorophyll content decreased for Ag2O and binary mixture (7% and 4%, respectively) and increased for TiO2 (5%) at 10 mg/kg soil-sludge. The toxic interaction between Ag2O and TiO2 NPs was additive at both exposure concentrations. Ag2O NPs had higher tendency of root surface adsorption than TiO2 NPs. Metal content in spinach leaves at highest exposure concentration was Ag: 2.6 ± 0.55 mg/g plant biomass(for Ag2O NPs) and 1.02 ± 0.32 mg/g plant biomass (for Ag2O + TiO2 NPs) and for Ti: 1.12 ± 0.78 (for TiO2 NPs) mg/g plant biomass and 0.58 ± 0.41 mg/g (for Ag2O + TiO2 NPs). The inadvertent ingestion of NPs- contaminated spinach resulted in projected daily intake (DI) of Ag and Ti for different age-mass classes (child to adult) exceeding the oral reference dose for toxicity during oral ingestion. In conclusion, we report no acute toxicity of single and binary mixture of NPs to spinach but significant accumulation of Ag and Ti metals in spinach leaves. There are high chances that ingestion of spinach grown in such environment might lead to human health risks.


Assuntos
Nanopartículas/toxicidade , Poluentes do Solo/toxicidade , Spinacia oleracea/efeitos dos fármacos , Biomassa , Clorofila , Humanos , Nanopartículas Metálicas/toxicidade , Metais/toxicidade , Nanopartículas/análise , Folhas de Planta/química , Esgotos , Solo , Poluentes do Solo/análise , Spinacia oleracea/crescimento & desenvolvimento , Titânio/farmacologia
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