ESTUDO DA PREPARAÇÃO E DA MORFOLOGIA DE SUPERFÍCIE DE ALUMINA NANOPOROSA AUTO-ORGANIZADA

A alumina nanoporosa é um material que apresenta nanocanais auto-ordenados espontaneamente em formato hexagonal. Produzida a partir da anodização do alumínio metálico, vem sendo usada como molde para produção de materiais em escala nanométrica. Este trabalho teve como objetivo o estudo da preparação e a caracterização morfológica da alumina nanoporosa auto-organizada. A alumina nanoporosa foi preparada seguindo-se a metodologia proposta por Masuda e Fukuda (1995), um método de dois passos de anodização que consiste em anodizar a amostra de alumínio, remover a camada de óxido de alumínio (alumina) formada e, em seguida, repetir o processo de anodização, sob as mesmas condições da primeira. Este procedimento resulta em alumina com poros de dimensão na faixa de dezenas de nanômetros, com estreita distribuição de tamanhos e com alto grau de ordenação.AbstractNanoporous alumina is a typical material that exhibits self-ordered nanochannels spontaneously organized in hexagonal shape. Produced by anodizing of metallic aluminum, it has been used as a template for production of materials at the nanoscale. This work aimed to study the preparation of nanoporous alumina by anodic anodizing of metallic aluminum substrates. The nanoporous alumina was prepared following the methodology proposed by Masuda and Fukuda (1995), a two-step method consisting of anodizing the aluminum sample in the potentiostatic mode, removing the layer of aluminum oxide (alumina) formed and then repeat the anodization process under the same conditions as the first anodization. This method produces nanoporous alumina with narrow pore diameter distribution and well-ordered structure

Influence of Temperature and Acid Etching Time on the Superficial Characteristics of Ti

We evaluated the influence of the etching time and temperature of an acid solution (HCl/H2SO4) on the chemical and topographical superficial characteristics of cpTi grade IV. Samples were analyzed by electron microscopy, interferometry, and grazing incidence XRD. The surfaces kept the irregularity aspect when submitted to the same etching temperature. On the other hand, the irregularities increased in size and depth with increasing etching time. The etching treatments that produced higher values for roughness parameters showed a combination of high temperature for a longer etching time. Some treatments produced very large irregularities, with a brittle surface in some regions. According to statistical correlation, the temperature made the strongest contribution in the variance of the mean values of the surface roughness parameters when compared to the etching time. Titanium and oxygen were the only elements on the surface in all groups. All test group samples showed the presence of titanium hydride

Immediate Placement of Implants into Infected Sites : A Systematic Review

Background Traditionally, before placing dental implants, the compromised teeth are removed and the extraction sockets are left to heal for several months. To preserve the alveolar bone level from the collapse caused by healing and to reduce treatment time in situations in which tooth extraction precedes implant placement, some clinicians began to install the implant immediately into the postextraction socket without waiting for the site to heal. Purpose The purpose of this study was to review the literature regarding treatment outcomes of immediate implant placement into sites exhibiting pathology after clinical procedures to perform the decontamination of the implant's site. The following questions were raised: Does the presence of periodontal or endodontic infection affect immediate implant placement success? What is suggested to address the infection in the socket prior to immediate placement? Materials and Methods An electronic search in PubMed (U.S. National Library of Medicine, Bethesda, MD, USA) was undertaken in March 2013. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included both animal and human studies, and excluded any review and case reports articles. The publication's intervention had to have been implant placement into a site classified as having an infection (periapical, endodontic, perioendodontic, and periodontal). Results The search strategy initially yielded 706 references. Thirty-two studies were identified within the selection criteria, from which nine were case reports and review articles and were excluded. Additional hand-searching of the reference lists of selected studies yielded five additional papers. Conclusions The high survival rate obtained in several studies supports the hypothesis that implants may be successfully osseointegrated when placed immediately after extraction of teeth presenting endodontic and periodontal lesions, provided that appropriate clinical procedures are performed before the implant surgical procedure such as meticulous cleaning, socket curettage/debridement, and chlorhexidine 0.12% rinse. However, more randomized controlled clinical trials with a longer follow-up are required to confirm this procedure as a safe treatment. Moreover, the outcome measures were not related to the type of infection; the classification of infection was often vague and varied among the studies. The benefits of antibiotic solution irrigation and systemic antibiotic administration in such conditions are not yet proved and remain unclear

Chemical and topographic analysis of treated surfaces of five different commercial dental titanium implants

We present a detailed investigation of the surface characteristics of five commercial titanium implants with different surface finishing (double acid etching, anodization and incorporation of Ca/P, acid etching and deposition of Ca/P, hydroxyapatite-blasting, acid etching and Ca/P-blasting) produced by five different manufacturers. A set of experimental techniques were employed to study the surface chemical composition and morphology: XPS, XRD, SEM, EDS, and AFM. According to the implat manufacturers, the addition of Ca and P at the implant surface is a main feature of these implants (except the double acid etched implant, which was included for comparative purpose). However, the results showed a great discrepancy on the final amount of these elements on the implant surface, which suggests a different effectiveness of the employed surface finishing methods to fix those elements on the implant surface. Our results show that only the method used by the manufacturer of hydroxyapatite-blasting surface finished implants was efficient to produce a hydroxyapatite coating. This group also showed the highest roughness parameters