ABSTRACT
This paper explores the features of both nanoporous and compact TiO2 films formed by titanium anodisation in two experimental conditions, given that they have completely different morphologies and properties than those found by our previous studies. After anodisation, samples have been subjected for 20 days to immersion tests in different media (H2O, H3PO4, and KOH). Surface morphology, phase composition and wettability of anodised films were investigated using FESEM, FTIR, Raman spectroscopy, contact angle measurements and XPS, and the hydrophilicity of modified surfaces was investigated by immersion tests. Nanoporous films exhibited hydrophobic surfaces, but contact angle values gradually decreased after immersing films in H2O, H3PO4 and KOH media, respectively. However, compact films produced superhydrophilic surfaces, both before and after immersion tests, with the exception of immersing the film in a H3PO4 medium due to film removal by acid attack. As for compact films, an unusual morphology revealed by the presence of cone-shaped particles might be responsible for the adsorption of -OH groups arranged so as to favour anatase phase formation.
ABSTRACT
BACKGROUND: Several studies proved that anodic oxidation improves osseointegration. This study aimed to optimize osseointegration through anodization in dental implants, obtaining anatase phase and controlled nanotopography. METHODS: The division of the groups with 60 titanium implants was: control (CG); sandblasted (SG); anodized (AG): anodized pulsed current (duty cycle 30%, 30 V, 0.2 A and 1000 Hz). Before surgery, surface characterization was performed using Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-ray Dispersive Energy Spectroscopy (EDS) and Raman Spectroscopy. For in vivo tests, 10 New Zealand white rabbits received an implant from each group. The sacrifice period was 2 and 6 weeks (n = 5) and the specimens were subjected to computed microtomography (µCT) and reverse torque test. RESULTS: AFM and SEM demonstrated a particular nanotopography on the surface in AG; the anatase phase was proved by Raman spectroscopy. In the µCT and in the reverse torque test, the AG group presented better results than the other groups. CONCLUSION: The chemical composition and structure of the TiO2 film were positively affected by the anodizing technique, intensifying the biological characteristics in osseointegration.
ABSTRACT
Várias ligas têm sido utilizadas na confecção de restaurações protéticas nos últimos anos. Essas ligas apresentam na sua composição ouro, paládio, prata, níquel, cobalto, cromo e titânio; quando na cavidade bucal são passíveis de corrosão, a qual pode empobrecer a estética e comprometer as propriedades físicas e biológicas. O objetivo deste trabalho foi avaliar a resistência a corrosão de duas ligas odontológicas, Ni-Cr e Ni-Cr-Ti em três tipos de colutórios bucais com diferentes ingredientes ativos: colutório I 0.5g/l de cloreto de cetilpiridíneo +0.05 de fluoreto de sódio; colutório II -0.05 de fluoreto de sódio + 0.03% de triclosan e colutório III 0.12% de diclonato de clorexidina. Curvas potenciodinâmicas foram realizadas por meio de potenciostato PAR283 e célula de vidro convencional de parede dupla para termostatização. Utilizou-se eletrodo de referência Ag/ AgCl, KClsat e auxiliar espiral de platina. A microestrutura das duas ligas foi observada por meio de microscopia ótica. Análise das curvas obtidas mostraram que a liga Ni-Cr foi menos reativa na presença de digluconato de clorexida a 0.12%, enquanto a liga Ni-Cr-Ti foi mais sensível para os outros dois tipos de colutório. Isto ocorreu, provavelmente, devido a presença de titânio na composição desta liga. Análise microestrutural revelou microsestrutura dendrítica na liga Ni-Cr e eutéticos na liga Ni-Cr-Ti
Several alloys have been used for prosthodontics restorations in the last years. These alloys have a number of metals that include gold, palladium, silver, nickel, cobalt, chromium and titanium and they are used in oral cavity undergo several corrosion. Corrosion can lead to poor esthetics, compromise of physical properties, or increased biological irritation. The objective of this study was evaluated corrosion resistance of two alloys Ni-Cr and Ni-Cr-Ti in three types of mouthwashes with different active ingredients: 0.5g/l cetylpyridinium chloride + 0.05% sodium fluoride, 0.05% sodium fluoride + 0.03% triclosan (with fluor) and 0.12% chlorohexidine digluconate. The potentiodynamic curves were performed by means of an EG&G PAR 283 potentiostat/galvanostat. The counter electrode was a platinum wire and reference electrode was an Ag/AgCl, KCl saturated. Before each experiment, working electrodes were mechanically polished with 600 and 1200 grade papers, rinsed with distilled water and dried in air. All experiments were carried out at 37.0oC in conventional three-compartment double wall glass cell containing mouthwashes. The microstructures of two alloys were observed in optical microscopy. Analysis of curves showed that Ni-Cr alloy was less reactive in the presence of 0.12% chlorohexidine digluconate while Ni-Cr-Ti alloy was more sensitive for others two types of mouthwashes (0.5g/l cetylpyridinium chloride + 0.05% sodium fluoride® and 0.05% sodium fluoride + 0.03% triclosan). This occurred probably due presence of titanium in this alloy. Microstructural analysis reveals the presence of dendritic and eutectic microstructures for NiCr and Ni-Cr-Ti, respectively
Subject(s)
Mouthwashes , Corrosion , TitaniumABSTRACT
The purpose of this work was to evaluate the effect of three commercial mouthwashes on the corrosion resistance of Ti-10Mo experimental alloy. Experiments were made at 37.0 +/- 0.5 degrees C in a conventional three-compartment double wall glass cell containing commercial mouthwashes. Three mouthwashes with different active ingredients were tested: (I) 0.05% sodium fluoride + 0.03% triclosan; (II) 0.5 g/l cetylpyridinium chloride + 0.05% sodium fluoride; (III) 0.12% chlorohexidine digluconate. The assessment of the individual effect of active ingredients was studied by using 0.05% sodium fluoride. Commercially pure titanium (CP Ti) was used as control. Microstructures from Ti-10Mo experimental alloy and CP Ti were also evaluated using optical microscopy. Ti-10Mo as-cast alloy shows the typical rapidly cooled dendrites microstructure (beta phase) while CP Ti has exhibited a metastable martensitic microstructure. Electrochemical behavior of dental materials here studied was more affected by mouthwash type than by Ti alloy composition or microstructure. In both alloys passivation phenomenon was observed. This process may be mainly related to Ti oxides or other Ti species present in spontaneously formed film. Small differences in passive current densities values may be connected with changes in film porosity and thickness. Protective characteristics of this passive film are lower in 0.05% sodium fluoride + 0.03% triclosan mouthwash than in the other two mouthwashes tested.
Subject(s)
Alloys/chemistry , Corrosion , Dental Alloys/chemistry , Molybdenum/chemistry , Mouthwashes/chemistry , Titanium/chemistry , Electrochemistry , Materials Testing , Microscopy, Electron, ScanningABSTRACT
O presente trabalho apresenta uma revisão da literatura com os principais estudos relacionados com o processo de corrosão de amálgamas dentários. Este fenômeno tem sido extensivamente estudada com respeito à fratura marginal, deterioração superficial, microestrutura da superfície corroída, liberação de produtos de corrosão e biocompatibilidade. A grande diversidade de amálgamas comerciais, suas complexas estruturas metalúrgicas, a constante variação na composição da saliva natural e as variáveis que condicionam os experimentos in vitro impedem a interpretação da corrosão como um processo global. Como conseqüência, limita-se o conhecimento principalmente sobre as transformações microestruturais que ocorrem na superfície de cada tipo de amálgama antes e após do processo de corrosão em condições in vivo ou in vitro
