Evaluation of the effect of diode laser application on the hydrophilicity, surface topography, and chemical composition of titanium dental implant surface.

PURPOSE: Attempts have been made to decontaminate the implant surface by using diode lasers. However, the parameters that provide efficient decontamination without altering the topography or surface characteristics of titanium implants are still unclear. The aim of the present study was to evaluate the effect of altering the power of diode laser (940 nm) application on the hydrophilicity, surface topography, and chemical composition of sandblasted, large grit, acid-etched (SLA) treated titanium alloy implant surface. MATERIALS AND METHODS: Thirty-six SLA-treated titanium discs (Dentis Co., Ltd.) were used in this study. The hydrophilicity of all discs was measured by using a contact angle goniometer (190 CA; Rame-hart Co, Ltd). Discs were randomly divided into four groups (n = 9 each) based on the power of the diode laser used. Group I (control, no lasing group), group II: treated with 1 W power, group III: 2 W power, and group IV: 3 W power. The chemical composition of the SLA discs was evaluated by using energy dispersive x-ray spectroscopy (EDX) before laser application. Hydrophilicity was reevaluated after the application of laser irradiation. The surface topography of all discs was examined. Changes in the chemical composition of the titanium discs were investigated following the lasing procedure. Morphometric analysis of the surface area (µm2 ) of the indentations created following laser application was also evaluated. Data were collected and the Shapiro-Wilk test of normality was used. Comparisons between the four study groups were done by using the Kruskal-Wallis test, while that to evaluate the morphometric analysis of the surface area was done by using One-way ANOVA (P < 0.05). RESULTS: The average contact angle of the drop of distilled water to the SLA discs significantly decreased after laser treatment (P < 0.05). The largest contact angle was measured in the control group, followed by the 1 W group, and the 2 W group. The smallest angle was measured in the 3 W group. Considerable surface alterations such as melting and flattening were observed on examination of the surface topography of the 3 W group followed by the 2 W group. The least changes were observed in association with the 1 W group in comparison to the control group. The EDX analysis showed the appearance of peaks of the oxygen and carbon elements after the lasing procedure with the highest percentage in the 3 W group. The average of the surface area of the created indentations significantly increased with increasing the power of the diode laser used (P < 0.05). CONCLUSIONS: The application of diode laser (940 nm) with 2 W and 3 W powers significantly altered the hydrophilicity, the surface topography, and the chemical composition of titanium discs. Diode laser (940 nm) with 1 W power can be safely used on SLA titanium implant surfaces with no damaging effect on the surface topography or hydrophilicity.

Methacrylic monomer derived from cardanol incorporated in dental adhesive as a polymerizable collagen crosslinker.

OBJECTIVES: The aim of this study was to evaluate the influence on MMP inhibition, dentin adhesion and physicochemical properties of an adhesive system incorporated with polymerizable collagen crosslinker monomer derived from cardanol. METHODS: The intermediary cardanol epoxy (CNE) was synthesized through cardanol epoxidation, followed by synthesis of cardanol methacrylate through methacrylic acid solvent-free esterification. Zymographic analysis was performed to evaluate the substances' ability to inhibit gelatinolytic enzymes. Collagen crosslinkers were added into adhesives systems according to the following groups: Ybond Universal® (Control), Ybond® + 2 % proanthocyanidin (PAC), Ybond® + 2 % unsaturated cardanol (Cardanol) and Ybond® + 2 % cardanol methacrylate (CNMA). Degree of conversion (DC) of the adhesives was assessed by FT-IR. Disk-shaped specimens were prepared for water sorption (WS) and solubility (SL) tests. Human third molars were sectioned to expose medium dentin and restored according to the different adhesives used (n = 5). Then, the specimens were cut into 1 mm2 sticks to evaluate, after 24 h and 6-month aging, microtensile bond strength (µTBS) and nanoleakage by scanning electron microscopy. Data were analysed with ANOVA and Tukey's post-test (α = 0.05). RESULTS: CNMA and PAC completely inhibited all forms of gelatinolytic enzymes. Cardanol achieved a significantly lowest DC, while the other groups did not differ from each other (p > 0.05). PAC achieved significantly higher water sorption, while CNMA solubility was significantly lower when compared to the other adhesives (p < 0.05). PAC provided a statistically higher 24 h and 6-month aging bond strength. Intermediary similar µTBS were presented by control and CNMA (p = 0.108). All adhesives applied attained significantly reduced bond strength after aging (p < 0.05). Interfaces created using CNMA were almost devoid of silver deposits initially, however all groups showed large amounts of silver deposits on resin-dentin interface subjected to water aging. SIGNIFICANCE: Although CNMA was effective in inhibiting gelatinolytic enzymes, when incorporated into a universal adhesive it could not promote less degradation of the adhesive interface after water aging. Since it is a hydrophobic monomer, CNMA did not interact well with dentin collagen, however it reduced the solubility of the adhesive system besides not interfering in its polymerization.

Research progress of superhydrophilic implants / 中国基层医药

In the past few decades, some studies reported that changing the specific surface properties of titanium implants, such as surface morphology, surface chemistry, surface charge and wettability, improved the bone bonding ability of titanium implants. Based on the existing evidence, this review paper analyzes the methods and characteristics of surface chemical modification of the superhydrophilic implants (Thommen INICELL?) that were listed in China in recent years, and clarifies the process of early osseointegration from the viewpoint of histomorphology, and evaluates its clinical application effects.

Evaluation of Elastomeric Impression Materials' Hydrophilicity: An in vitro Study.

INTRODUCTION: Hydrophilicity of dental impression materials is crucial for obtaining an accurate impression and necessary for the production of a well-fitting cast restoration. The most common technique for evaluation of hydrophilicity is a contact angle measurement. The aim of the present in vitro study was to compare the water contact angles of four groups of elastomeric impression materials, before and during setting. MATERIAL AND METHODS: Flattened specimens (n=10) of tested impression materials were prepared by the use of a Teflon mold with specific dimensions. A 5µl droplet of deionized water fell on the specimen, and photos were taken using a Nikon D3200 DSLR camera and a 105 mm macro lens (Nikorr, Nikon) in specific time points. RESULTS: The CAD/CAM material showed the highest contact angle measurements. The light body polyvinylsiloxane (PVS) material 1, polyether and vinylsiloxanether material showed comparable contact angle measurements especially at the initial time point. A statistically significant reduction of contact angles was reported during setup time for all PVS, PE and vinylsiloxanether materials, while the most expressed reduction of contact angle measurements, and thus the most significant increase of hydrophilicity were reported for light wash PVS material 2. CONCLUSIONS: The CAD/CAM impression material showed the most hydrophobic behavior. PVS materials showed excellent hydrophilicity. Polyether and polyvinyloxanether impression materials presented lower contact angle measurements, and thus superior hydrophilicity, compared with other tested materials initially and during setting. All tested impression materials presented a stepwise development of hydrophilicity during the setting stage.

Efficacy of hydrophilic resin-based sealant: A systematic review and meta-analysis.

OBJECTIVES: This meta-analysis review aims to answer two questions: 1) What is the effectiveness of hydrophilic resin-based sealant (RBS) in preventing/arresting pits and fissures caries in permanent teeth, and 2) What is the retention rate of a hydrophilic RBS as compared to alternative treatments. DATA: Randomized control trials investigating the efficacy of hydrophilic RBS compared to any other (placebo) treatment for permanent teeth. Outcomes were retention rate and caries prevention/arresting. SOURCES: A systematic search for eligible studies was conducted on six electronic databases (Scopus, Ovid MEDLINE, Ovid Embase, Cochrane; Web of Science, PubMed) from inception to March 2021. The Cochrane guidelines were used to classify the risk of bias. STUDY SELECTION/RESULTS: A systematic literature search resulted in 290 studies. Thirteen articles met our inclusion criteria and were included in the systematic review. Six articles were identified as good or fair quality and were included in the quantitative analysis. Meta-analysis results indicated that there is no significant difference in retention (RR 1.01, 95% CI:0.96-1.07, P-value 0.66), (RR 1.03, 95% CI: 0.89-1.19, P-value 0.0009) at six and twelve months, respectively. Likewise, for caries prevention there is no significant difference (RR 0.97, 95% CI: 0.91-1.03, P-value 0.19), (RR 0.30, 95% CI: 0.91-1.03, P-value 0.30) at six and twelve months. CONCLUSIONS: This meta-analysis showed no statistically significant difference between the hydrophilic RBS and alternative treatment options (such as conventional resin or glass ionomer) regarding retention or caries prevention at six- and twelve-month follow-up. Future studies are required to investigate longer-term outcomes.

Marine Gel Interactions with Hydrophilic and Hydrophobic Pollutants.

Microgels play critical roles in a variety of processes in the ocean, including element cycling, particle interactions, microbial ecology, food web dynamics, air-sea exchange, and pollutant distribution and transport. Exopolymeric substances (EPS) from various marine microbes are one of the major sources for marine microgels. Due to their amphiphilic nature, many types of pollutants, especially hydrophobic ones, have been found to preferentially associate with marine microgels. The interactions between pollutants and microgels can significantly impact the transport, sedimentation, distribution, and the ultimate fate of these pollutants in the ocean. This review on marine gels focuses on the discussion of the interactions between gel-forming EPS and pollutants, such as oil and other hydrophobic pollutants, nanoparticles, and metal ions.

Back to the multi-step adhesive system: A next-generation two-step system with hydrophobic bonding agent improves bonding effectiveness.

This study evaluated the bonding effectiveness of a newly developed two-step hydrophobic bonding material. Three groups using different bonding systems were compared: BZF group, using the new bonding system (BZF-29; GC, Tokyo, Japan); GPB group, using a one-step bonding system (G-Premio Bond; GC); and SE2 group, using a two-step bonding system (CLEARFIL SE Bond 2; Kuraray Noritake Dental, Tokyo, Japan). Microtensile bond strength (µTBS) was measured after storage in water for 24 h, 3 months and 6 months (n=25/group). Fracture surfaces were observed under scanning electron microscopy. The BZF group showed significantly higher µTBS than the other groups (p<0.001). Dominant failure patterns were cohesive failure for the BZF group (48-84%), mixed failure for the SE2 group (48-60%) and interface failure between adhesive and resin composite for the GPB group (48-52%). The hydrophobicity of the BZF-29 bonding system improves the long-term bonding effectiveness between adhesive and resin composite.

Application of Design of Expert software for evaluating the influence of formulation variables on the encapsulation efficacy, drug content and particle size of PEO-PPO-PEO/Poly (DL-lactide-co-caprolactone) nanoparticles as carriers for SN-38.

Background and aims: Hydrophobic substances are mainly encapsulated into polymer nanocarriers in order to improve their solubility, enable their administration, at the same time to empower targeted tissue or cell specific delivery of the drug using the encapsulating vehicle as targeting and controlled release platform. 7-Ethyl-10-hydroxycamptothecin (SN-38) is an active metabolite of Irinotecan, showing 100-fold to 1000-fold higher effect than Irinotecan, but its clinical use is limited because of its extreme hydrophobicity, as it is practically insoluble in most physiologically compatible and pharmaceutically acceptable solvents. Method: In order to fully exploit the potential of the nanoprecipitation as a method for preparation of Poly(DL-lactide-co-caprolactone)-poly(ethylene oxide) - poly(propylene oxide) - poly(ethylene oxide) (P(DL)LCL/PEO-PPO-PEO) nanoparticles and evaluate the influence of the polymer P(DL)LCL, stabilizing agent PEO-PPO-PEO copolymer (Lutrol F127) and the drug concentration (SN-38) upon drug entrapment efficiency, size and drug content, a D-optimal experimental design for response surface using Design Expert Version 9.0.4.1. software investigation was created and statistically analyzed. Results: We have observed that at higher SN-38 concentration during the preparation procedure (nanoprecipitation, solvent diffusion method), and due to its extremely low water solubility, the drug will start to precipitate as unprotected crystals at a faster pace compared to polymer aggregation, leading to extremely low encapsulation efficacy and waste of the active compound. The most desirable combination of factor settings are SN-38 = 0.5 mg, Polymer = 5 mg and F127 = 4%. Conclusion: This investigation utilizes the design of experiment approach and extends the primary understanding of impact of formulation development of P(DL)LCL/PEO-PPO-PEO nanoparticles as carriers for SN-38.

Sequence characteristics responsible for protein-protein interactions in the intrinsically disordered regions of caseins, amelogenins, and small heat-shock proteins.

Milk caseins and dental amelogenins are intrinsically disordered proteins (IDPs) that associate with themselves and others. Paradoxically, they are also described as hydrophobic proteins, which is difficult to reconcile with a solvent-exposed conformation. We attempt to resolve this paradox. We show that caseins and amelogenins are not hydrophobic proteins but they are more hydrophobic than most IDPs. Remarkably, uncharged residues from different regions of these mature proteins have a nearly constant average hydropathy but these regions exhibit different charged residue frequencies. A novel sequence analysis method was developed to identify hydrophobic and order-promoting regions that would favor conformational collapse. We found that such regions were uncommon; most hydrophobic and order-promoting residues were adjacent to hydrophilic or disorder-promoting residues. A further reason why caseins and amelogenins do not collapse is their high proportion of disorder-promoting proline residues. We conclude that in these proteins the hydrophobic effect is not large enough to cause conformational collapse but it can contribute, along with polar interactions, to protein-protein interactions. This behaviour is similar to the interaction of the disordered N-terminal region of small heat-shock proteins with either themselves during oligomer formation or other, unfolding, proteins during chaperone action.

Caracterização interna de materiais restauradores indiretos com diferentes condicionamentos de superfície / Internal characterization of indirect restorative materials with different surface etching protocols

Objetivo: O objetivo do estudo foi avaliar o efeito da aplicação de ácido fluorídrico com diferentes tempos e concentrações na superfície de materiais restauradores indiretos obtidos a partir de blocos utilizados na tecnologia CAD-CAM. Materiais e Métodos: Amostras dos materiais restauradores indiretos medindo 4x4x0,8mm foram obtidos a partir de blocos CAD para cada material estudado: resina nanocerâmica Lava Ultimate (3M Espe), monossilicato de lítio reforçado por zircônia Celtra Duo (Dentsply) e cerâmica híbrida Vita Enamic (Vita). Os materiais foram submetidos à aplicação de ácido fluorídrico com concentração de 5% ou 10%, sendo o mesmo aplicado pelos tempos de 20, 40, 60 ou 90 segundos. Um grupo controle para cada material foi avaliado, sem nenhum tratamento de superfície, contabilizando nove grupos de cada material (n=10). As amostras foram avaliadas em relação à rugosidade de superfície (Ra e Rz), avaliadas em microscopia óptica confocal; ângulo de contato (θ), energia de superfície (s) e energia livre total de interação (∆G) avaliados em goniômetro, e resistência de união ao cimento resinoso avaliada através do teste de microcisalhamento. Imagens das amostras foram obtidas em microscopia eletrônica de varredura (MEV), microscopia óptica confocal e microscopia de força atômica. Os dados de rugosidade de superfície, ângulo de contato, energia de superfície, energia livre total de interação e resistência de união foram submetidos à ANOVA dois fatores e teste de Tukey (p<0,05). Resultados: Os resultados mostraram que, de maneira geral, o monosilicato de lítio reforçado por zircônia Celtra Duo apresentou melhores resultados quando submetido ao condicionamento com ácido fluorídrico 10% por 40 ou 60 segundos de aplicação. A resina nanocerâmica Lava Ultimate apresentou melhor performance quando condicionada com ácido fluorídrico 10% por 20 ou 40 segundos, enquanto que a cerâmica híbrida Vita Enamic apresentou melhores resultados quando condicionada com ácido fluorídrico 5% por 90 segundos. Conclusão: Cada material interagiu de maneira diferente ao condicionamento com ácido fluorídrico, sendo que o conhecimento do adequado protocolo para cada material é essencial para garantir melhorias nos processos de adesão e durabilidade das restaurações indiretas. Celtra Duo apresentou de maneira geral propriedades mecânicas superiores aos demais. Relevância clínica: Recomenda-se protocolos específicos de tratamento de superfície com ácido fluorídrico de acordo com a composição de cada material restaurador indireto(AU)

Purpose: The aim of this study was to evaluate the effect of different times and concentration of hydrofluoric acid etching on the surface of indirect restorative materials obtained from blocks used in CAD-CAM technology. Methods and Materials: Samples of indirect restorative materials measuring 4x4x0.8mm were obtained for each restorative material studied: Lava Ultimate nanoceramic resin (3M Espe), Celtra Duo zirconia-reinforced lithium silicate ceramic (Dentsply) and Vita Enamic polymer-infiltrated ceramic-network material (Vita). The materials were submitted to etching with 5% or 10% hydrofluoric acid for 20, 40, 60 or 90 seconds. A control group for each material was evaluated without any surface treatment, totaling nine experimental groups for each material (n = 10). The samples were evaluated in relation to surface roughness (Ra and Rz), evaluated by confocal optical microscopy; contact angle (θ), surface energy (s) and total free interaction energy (∆G) evaluated by goniometer; and microshear bond strength to resin cement. Sample images were obtained by scanning electron microscopy (SEM), confocal optical microscopy and atomic force microscopy. Data of surface roughness, contact angle, surface energy, total free interaction energy and bond strength were submitted to two-way ANOVA and Tukey test (p<0.05). Results: The results showed that, in general, the Celtra Duo zirconia-reinforced lithium silicate ceramic showed better results when subjected to etching with 10% hydrofluoric acid for 40 or 60 seconds. Lava Ultimate nanoceramic resin showed better performance when etched with 10% hydrofluoric acid for 20 or 40 seconds, while Vita Enamic polymer-infiltrated ceramic-network showed better results when etched with 5% hydrofluoric acid for 90 seconds. Conclusion: Each material showed different characteristics after etching with hydrofluoric acid, and the knowledge of the proper protocol for each material is essential to ensure improvements in the adhesion process and durability of indirect restorations. Celtra Duo presents general ways of mechanical properties superior to the others. Clinical relevance: Specific surface treatment protocols with hydrofluoric acid are recommended based on the different compositions of indirect restorative materials(AU)

Influence of Implant Surface Coated with pH Buffering Agent on Early Osseointegration

PURPOSE: Surface treatment with pH buffering agent has been developed to achieve higher and faster osseointegration. The aim of this study was to evaluate its influence by measuring removal torque and analyzing histological characteristics. MATERIALS AND METHODS: Titanium implants with following surfaces were used in this study: sand-blasted acid-etched (SA) surface (SA group as control I group), SA surface in calcium chloride aqueous solution (CA group as control II group) and SA surface coated with pH buffering agent (pH group as test group). Removal torque test after 2 weeks and bone-to-implant contact and bone area analyses at 2 and 4 weeks were performed. RESULT: The rotational torque values at 2 weeks were significantly higher in pH group (107.5±6.2 Ncm, P < 0.05). The mean values of bone-to-implant contact at 2 and 4 weeks were both higher in pH group (93.0%±6.4% at 2 weeks, 88.6%±5.5% at 4 weeks) than in SA group (49.7%±9.7% at 2 weeks, 47.3%±20.1% at 4 weeks) and CA group (73.7%±12.4% at 2 weeks, 72.5%±10.9% at 4 weeks) with significances (P < 0.05). The means of bone area showed significantly higher numbers in pH group (39.5%±11.3% at 2 weeks, 71.9%±10.9% at 4 weeks, P < 0.05). CONCLUSION: Our findings demonstrated that surface modification with pH buffering agent improved early osseointegration with superior biomechanical property.

Investigation of the pH-dependence of dye-doped protein-protein interactions.

Proteins can dramatically change their conformation under environmental conditions such as temperature and pH. In this context, Glycoprotein's conformational determination is challenging. This is due to the variety of domains which contain rich chemical characters existing within this complex. Here we demonstrate a new, straightforward and efficient technique that uses the pH-dependent properties of dyes-doped Pig Gastric Mucin (PGM) for predicting and controlling protein-protein interaction and conformation. We utilize the PGM as natural host matrix which is capable of dynamically changing its conformational shape and adsorbing hydrophobic and hydrophilic dyes under different pH conditions and investigate and control the fluorescent properties of these composites in solution. It is shown at various pH conditions, a large variety of light emission from these complexes such as red, green and white is obtained. This phenomenon is explained by pH-dependent protein folding and protein-protein interactions that induce different emission spectra which are mediated and controlled by means of dye-dye interactions and surrounding environment. This process is used to form the technologically challenging white light-emitting liquid or solid coating for LED devices.

Optical quality evaluation of pseudophakic eyes implanted different materials of IOL by optical quality analysis system / 中华实验眼科杂志

Background Phacoemulsification with IOL implantation can reduce the light scattering caused by cataract,but many patients with IOLs implantation complained of glare or blurred vision.IOLs from different materials will affect IOL refractive index (RI) and optical design,which affect the value of scattered light of IOLs implantation.Objective This study was to analyze the effect of IOL materials on optical quality in pseudophakic eyes with optical quality analysis system (OQAS).Methods The clinical data of 95 eyes from 65 patients with age-related cataract who received phacoemulcification with IOL implantation in Tianjin Eye Hospital from March to Octomber were retropectively analyzed.Three types of lOL,including AR40e,Acrysof SA60 AT and Rayner 620H,were implanted in 32 eyes,30 eyes and 33 eyes,respectively.The visual quality indexes were detected and evaluated using OQAS,including uncorrected distance visual acuity (UCDVA,LogMAR),objective scatter index (OSI),modulation transfer function cut off (MTF cut off),strehl ratio (SR),Profile width at 50％ point scatter function (PSF),Profile width at 10％ PSF and contrast visual acuity under the 100％,20％,9％ contrasts.Results The UCDVA was ≥ 0.3 in the eyes of AR40e group,SA60AT group and 620H group 1 month after surgery.No significant difference was found in the best corrected distance visual acuity (BCDVA,LogMAR) among three groups (F =1.362,P =0.246).The OSI was 1.72±1.11,1.89±1.07 and 2.13±1.13 in the AR40e group,SA60AT group and 620H group,with a significant difference among the groups (F =3.638,P =0.045),and the OSI was significantly lower in the AR40e group than that in the SA60AT group or 620H group (both at P＜0.05).No considerable difference in MTF cut off among the groups (F =2.401,P =0.192).The SR value was significantly elevated and the PSF at both 50％ and 10％ was declined in the AR40e group compared with the SA60AT group and 620H group (all at P＜0.05).A significant difference was found in 9％ contrast visual acuity among the three groups (F=3.866,P=0.038),and 9％ contrast visual acuity was better in the AR40e group than that in the SA60At group or the 620H group (both at P＜ 0.05).Negative correlations were found betwee OSI and BCDVA in the AR40e group,SA60AT group and 620H group (r=-0.275,P=0.041;r=-0.287,P=0.042;r=-0.233,P=0.037).Conclusions OQAS can evaluate optical quality of cataract patients after opeartion objectively.Material and RI of IOL have a great effect on visual quality after phacoemulcification with IOL implantation,especially under the low contrast environment.The operated eyes implanted hydrophobic acrylic IOLs with a lower RI can get better optical quality in comparison with the eyes implanted hydrophilic IOLs.

Effect of an Extra Hydrophobic Resin Layer on Repair Shear Bond Strength of a Silorane-Based Composite Resin.

OBJECTIVES: Composite repair is a minimally invasive and conservative approach. This study aimed to evaluate the effect of an additional hydrophobic resin layer on the repair shear bond strength of a silorane-based composite repaired with silorane or methacrylate-based composite. MATERIALS AND METHODS: Sixty bar-shaped composite blocks were fabricated and stored in saline for 72 hours. The surface of the samples were roughened by diamond burs and etched with phosphoric acid; then, they were randomly divided into three groups according to the repairing process: Group 1: Silorane composite-silorane bonding agent-silorane composite; group 2: Silorane composite-silorane bonding agent-hydrophobic resin-silorane composite, and group 3: Silorane composite-silorane bonding agent-hydrophobic resin methacrylate-based composite. Repairing composite blocks measured 2.5×2.5×5mm. After repairing, the samples were stored in saline for 24 hours and thermocycled for 1500 cycles. The repair bond strength was measured at a strain rate of 1mm/min. Twenty additional cylindrical composite blocks (diameter: 2.5mm, height: 6mm) were also fabricated for measuring the cohesive strength of silorane-based composite. The data were analyzed using One-way ANOVA and the post hoc Tukey's test (α=0.05). RESULTS: Cohesive bond strength of silorane composite was significantly higher than the repair bond strengths in other groups (P<0.001). The repair bond strength of group 3 was significantly higher than that of group 1 (P=0.001). CONCLUSION: Application of an additional hydrophobic resin layer for repair of silorane-based composite with a methacrylate-based composite enhanced the repair shear bond strength.

Avaliação de propriedades de superfície da liga Ti-35Nb-7Zr-5Ta submetida à anodização e seus efeitos na adesão bacteriana / Evaluation of the surface properties of the Ti-35Nb-7Zr-5Ta subjected to anodization and their effects on bacterial adhesion

Este estudo comparou as propriedades de superfície e a adesão Streptococcus mutans na liga Ti-35Nb-7Zr-5Ta e no titânio comercialmente puro (Ti cp) antes e após a anodização. Foram utilizados discos (Ø8mmx2mm; N = 40) divididos em 2 grupos: T (Ti cp), TNZT (Ti-35Nb7Zr-5Ta), e subdivididos conforme a realização (A+) ou não (A-, controle) da anodização eletroquímica (300 V, 1 min) em ß-glicerofostato de sódio + acetato de cálcio. As propriedades avaliadas foram: topografia de superfície e identificação qualitativa dos elementos químicos (microscópio eletrônico de varredura-MEV/EDS), energia livre de superfície (ELS, mensurada em goniômetro) e rugosidade média (Ra, determinada em rugosímetro). Para avaliação da adesão bacteriana, os discos foram contaminados com Streptococcus mutans (NTCC 25175) para determinação de UFC/mL e do padrão de adesão (MEV). Os valores de Ra e ELS de cada grupo foram comparados (Avs. A+ ) por meio do teste Kruskal-Wallis associado ao teste de Dun (α = 0,05). Os valores de Ra (µm) e ELS (mN/m), respectivamente, foram: A- - T=0,97/44,24; TNZT=0,17/36,68; A+ - T=1,21/56,88; TNZT=0,53/53,64, com aumento significante de ambas propriedades (p < 0,05) após a anodização. A análise em MEV/EDS indicou a formação de uma camada multiporosa, com deposição de íons Ca e P nos subgrupos A+ . Após a anodização houve aumento na adesão do patógeno apenas na liga TNZT. Conclui-se que a anodização do Ti cp e da liga TNZT alteram as propriedades de superfície com potencial para melhorias na osseointegração, contudo há aumento na adesão de S. mutans na liga TNZT

The aim of this study was to compare the surface properties and the adhesion of Streptococcus mutans on Ti-35Nb-7Zr-5Ta and commercially pure titanium (cp Ti) before and after the anodization. Discs (Ø8mmx2mm, N=40) were divided into 2 groups: T (cp Ti), TNZT (Ti-35Nb-7Zr5Ta), and subdivided in untreated (A- , control) or anodic treated (A+ ) in ßglicerofostato + calcium acetate (300 V, 1min). The evaluated surface properties were: surface topography and qualitative identification of chemical elements (in scanning electron microscope -SEM/EDS), surface free energy (SFE, measured with a goniometer), and the average roughness (Radetermined in profimoleter). The discs were contaminated with Streptococcus mutans (NTCC 25175) for determination of CFU/mL; the surfaces with adhered viable cell were also analyzed with SEM. The values of Ra and ELS were compared (Avs . A+ ) by means of Kruskal-Wallis associated Dun test (α=0.05). The median Ra (µm) and ELS (mN/m), respectively, were: A-T=0.97/44.24; TNZT=0.17/36.68; A+ T=1.21/56.88; TNZT=0.53/ 53.64. All groups showed significantly higher values of Ra and ELS (p < 0.05) after anodizing. The analysis in SEM/EDS indicated the formation of a multiporous layer with deposition of Ca and P ions. Only anodic treated TNZT exhibited an increase in adhesion of S. mutans. It was concluded that the anodic tretament of Ti cp and TNZT change the surface properties with potential improvements for osseointegration, despite the increase in the adhesion of S. mutans on TNZT

Addition of silver nanoparticles reduces the wettability of methacrylate and silorane-based composites

Incorporation of silver nanoparticles into composite resins is recommended for their reported antibacterial properties, but this incorporation can affect the wettability of such materials. Therefore, this study evaluated the effect of nano-silver addition to silorane-based and methacrylate-based composites on their contact angle. Nano-silver particles were added to Z250 (methacrylate-based) and P90 (silorane-based) composites at 0.5% and 1% by weight. The control group had no additions. SEM-EDX analysis was performed to confirm the homogeneity of the nano-silver distribution. Seventy-two composite discs were prepared and standardized to the identical surface roughness values, and then distributed randomly into 6 groups containing 12 samples each (N = 12). Two random samples from each group were observed by atomic force microscopy. Distilled water contact angle measurements were performed for the wettability measurement. Two-way ANOVA, followed by the Tukey-HSD test, with a significance level of 5%, were used for data analysis. It was observed that wettability was significantly different between the composites (p = 0.0001), and that the addition of nano-silver caused a significant reduction in the contact angle (p = 0.0001). Wettability varied depending on the concentration of the nano silver (p = 0.008). Silorane-based composites have a higher contact angle than methacrylate-based composites. Within the limitations of this study, it can be concluded that the addition of 0.5% nano-silver particles to the composites caused a decrease in the contact angle of water.