Desenvolvimento de uma membrana alternativa, nao reabsorvivel, para uso em regeneração tecidual guiada (RTG)

Orientador: Simonides ConsaniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O trabalho objetivou o desenvolvimento de uma membrana alternativa, de baixo custo, para utilização na técnica de REGENERAÇÃO TECIDUAL GUIADA (RTG) em Periodontia. Para isso utilizou-se como substrato da mesma fibra entrelaçadas de celulose constituintes de papel filtro de uso comercial, com espessura de aproximadamente 200 'mu'm. Este substrato foi embebido com uma mistura de resina epóxica com material de carga constituido de 'CaCO IND. 3' e ZnO. Estes dois componentes foram balanceados na mistura para se atingir uma rigidez adequada para manutenção do espaço periodontal na técnica de RTG, baseados em sua curvas de distribuição granulométrica (CDG). A membrana resultante foi submetida aos ensaios de: I) avaliação quanto a sua característica de material inerte; II) resistência ao rasgamento com fio de sutura; III) flexibilidade em curvaturas de pequeno ângulo de dobradura; IV) espessura e V) rigidez. Foi concluído dentro da proposta do trabalho, que a membrana proposta possui: I) característica de material inerte,mesmo em situações onde a agressividade química é elevada; II) resistência ao rasgamento relativa aproximadamente duas vezes maior que a membrana comercial utilizada na comparação; III) resistência a ruptura na região de dobramento a pequenos diâmetros; IV) uma rigidez razoável para promover e manter o espaço periodontal exigido na recuperação óssea na técnica de RTGAbstract: The development of an alternative low cost membrane for use in guided tissue regeneration (GTR) is presented. The membrane is prepared fiom a 200 'mu'm thick cellulose substrate, embedded in epoxy resin. The filler materiais 'CaCO POT. 3' and ZnO were used to attain the flexibility and rigidity necessary to keep the periodontal space. The inorganic formulation of the composite membrane was achieved fiom the analysis of the granulometric distribution curve. No liberation of inorganic or organic residues is detected. The membrane was also checked: for the resistance to tear, small angle bending flexibility, rigidity and thickness. In conclusion the developed material presents: I) the inert material features, even in situations of high aggressive chemical medium; II) the relative tear resistance twice higher that found for the commercial membrane used for comparison; III) the resistance to rupture in the small angle bending diameters and IV) the rigidity enough to keep the periodontal gap suitable for the bone regeneration using the GTRDoutoradoMateriais DentariosDoutor em Odontologi

Efeito da diluição do Rematitan Plus líquido sobre as dimensões de uma incrustação MOD

The effects of the dilution of the Rematitan Plus liquid on the dimensions of an inlay MOD model were evaluated in this study. Twelve wax templates were built in a single matrix. Then they were separated into three groups. Each group was embedded in three different dilutions of Rematitan Plus, all of them recommended by the manufacturer (minimal, maximum and intermediate). From referential marks made on the matrix, the specimens were measured in M-D and B-L directions. We noticed that, in most cases, variations on the dilution did not change the dimensions of the inlays in a significant way. Furthermore, we observed that the properties of the wax used as a template for the construction of the inlays were more significant in the dimensional alterations than the dilution of the Rematitan Plus liquid.Avaliou-se o efeito da diluição do Rematitan Plus líquido sobre as dimensões de uma incrustação MOD. A partir de uma matriz, foram confeccionados doze padrões de cera divididos em três grupos. Cada grupo foi incluído em uma diluição de Rematitan Plus líquido dentre aquelas recomendadas pelo fabricante (mínima, máxima e uma intermediária). A partir de marcas de referência feitas na matriz, as peças foram medidas no sentido M-D e V-L. Observou-se que a variação na diluição não alterava significativamente as dimensões da incrustação na maioria dos casos. Além disso, observou-se que as propriedades da cera utilizada como padrão para a confecção das incrustações foi mais significativa na alteração dimensional que a diluição do líquido do revestimento

Analysis of the point-counting and planimetric methods in the quantification of the biofilm of dentures: a study of methodological validation

Dois métodos de quantificação de biofilme da dentadura (contagem de pontos e planímetro) foram testados e comparados com o método de pesagem de papel e Índice de Higiene de Prótese. Superfícies internas de 62 próteses foram coradas, fotografadas e as áreas total e do biofilme foram projetadas em papel e contornadas com grafite. O método de contagem de pontos (experimental 1) foi aplicado com uma grade de pontos. Para o método do planímetro (experimental 2), as áreas foram medidas com um planímetro digital e para o método de pesagem (controle 1) foram recortadas e pesadas em balança de precisão. No Índice de Higiene de Prótese (controle 2), utilizou-se a atribuição de escores. Os resultados mostraram uma porcentagem de concordância entre os métodos experimentais e controle 1 de 82% (contagem de pontos) e 95% (planímetro), bem como alto grau de correlação (r = 0,98; r = 0,99) entre os valores obtidos. Quando comparados com o controle 2, houve concordância em 55% (contagem de pontos) e 37% (planímetro) dos casos. Os métodos experimentais podem ser úteis em estudos clínicos para avaliação da eficácia de agentes de higienização.Two methods of quantification of the biofilm (point-counting and planimetric) were tested and compared with the paper-weighing method and with the Prosthesis Hygiene Index. The internal surfaces of 62 complete dentures were stained and photographed. The slides were projected on a paper sheet. The total area and the area covered with biofilm were contoured using a black pencil. The point-counting method (experimental 1) was carried out on a mesh of equidistant points. For the planimetric method (experimental 2), the areas of interest were measured by means of a digital planimeter. In the paper-weighing method (control 1) the areas of interest were cut and weighed on a precision scale. In the determination of the Prosthesis Hygiene Index (control 2), the accumulation of biofilm was estimated by means of a scoring method. The results revealed an agreement rate of 82% between the paper-weighing method and the point-counting method, and an agreement rate of 95% between the former and the planimetric method, which was confirmed by high coefficients of correlation (0.98 and 0.99, respectively). The comparison with the Prosthesis Hygiene Index resulted in 55% of agreement with the point-counting method and in 37% of agreement with the planimetric method. The experimental methods can be useful in clinical studies involving the evaluation of the performance of denture cleansers

Effects of the dilution of the Rematitan Plus liquid on the dimensions of an inlay MOD

Avaliou-se o efeito da diluição do Rematitan Plus líquido sobre as dimensões de uma incrustação MOD. A partir de uma matriz,foram confeccionados doze padrões de cera dividido sem três grupos.Cada grupo foi incluído em uma diluição de Rematitan Plus líquido dentre aquelas recomendadas pelo fabricante (mínima, máxima e uma intermediária).A partir de marcas de referência feitas na matriz,as peças foram medidas no sentido M-DeV L.Observou-seque a variação na diluição não alterava significativamente as dimensões da incrustação na maioria dos casos. Além disso, observou se que as propriedades da cera utilizada como padrão para a confecção das incrustações foi mais significativa na alteração dimensional que a diluição do líquido do revestimento

Radiopacity and microhardness changes and effect of X-ray operating voltage in resin-based materials before and after the expiration date

This study observed alteration in the radiopacity and microhardness of expired resin-based materials compared to non-expired materials and the operating characteristics of the X-ray source used. Five 2 mm-thick cured specimens were prepared for each material: composite resins (P60®, Z100®), and a compomer (Dyract AP®). Radiopacity of the specimens was evaluated comparing the density of the resin-based material to an equivalent (mm) density of a 99.5% pure aluminum step wedge using a transmission densitometer. Surface microhardness measurements were carried out using a calibrated Vickers indenter on three different points of the same surface. ANOVA and Tukey tests (pre-set alpha = 0.05) revealed that expired materials showed no significant change in radiopacity. One material (Filtek P60) demonstrated lower radiopacity with lower KVp. Change in microhardness wa s statistically significant for Z100: for this material, the microhardness after expiration was significantly lower than before the expiration date

Chitosan as a Bioadhesive Agent Between Porphyrins and Phospholipids in a Biomembrane Model

Porphyrins are currently used in photodynamic therapy as photosensitizers. In this paper we studied the interaction of two charged porphyrins, 5, 10, 15, 20-mesotetrakis(N-metyl-4-pyridyl) porphyrin, (TMPyP/chloride salt) cationic, and 5, 10, 15, 20-meso-tetrakis(sulfonatophenyl) porphyrin, (TPPS(4)/sodium salt) anionic, nanoassembled in phospholipid Langmuir monolayers and Langmuir-Blodgett films. Furthermore, we used chitosan to mediate the interaction between the porphyrins and the model membrane, aiming to understand the role of the polysaccharide in a molecular level. The effect of the interaction of the photosensitizers on the fluidity of the lipid monolayer was investigated by using dilatational surface elasticity. We also used photoluminescence (PL) spectroscopy to identify the porphyrins adsorbed in the phospholipid films. We observed an expansion of the monolayer promoted by the adsorption of the porphyrins into the lipid-air interface which was more pronounced in the case of TMPyP, as a consequence of a strong electrostatic interaction with the anionic monolayer. The chitosan promoted a higher adsorption of the porphyrins on the phospholipid monolayers and enabled the porphyrin to stay in its monomeric form (as confirmed by PL spectroscopy), thus demonstrating that chitosan can be pointed out as a potential photosensitizer delivery system in photodynamic therapy.FAPES

Effect of chemical denture cleansers on flexural resistance and color changes of microwave-polymerized acrylic resins

Aim: The aim of this study was to assess the flexural resistance and color alterations of microwave-polymerized acrylic resins immersed in denture cleansers for different periods of time. Methods: Forty-five rectangular specimens (65x10x3mm) of each commercial brand of the microwave-activated acrylic resins (Vipi Wave and Onda Cryl) were divided in three denture cleanser groups (Bony Plus, Corega Tabs and Efferdent Plus) and a control group (immersion in water). Soaking trials of 15 min and 8 h simulated 30 days of use. The flexural strength test was carried out in a universal testing machine. Color alterations were assessed by visual inspection of photographs. The results obtained in the flexural test, in kgf, were converted to MPa and these values were submitted to analysis of variance with a 5% significance level. Results: There were no significant differences (p<0.05) between Onda Cryl (85.61±12.76) and Vipi Wave (89.8±19.95) after the soaking trials regarding the use of different denture cleansers. No differences were found in relation to the solutions [Bony Plus (88.52±9.89), Corega Tabs (88.75±12.71) and Efferdent (85.86±12.11)], soaking periods [control (87.17±12.92), 15 min (88.05±11.74) and 8 h (87.91±10.30)], and interactions during the 30 days of simulated use. Visual inspection did not detect any color alterations. Conclusions: Denture cleansers, when used according to the manufacturers&apos; instructions, did not cause any mechanical or visual alterations in the microwave-polymerized acrylic resins after a simulated period of 30 days of use

Formation of thin luminescent Eu 3 þ -LB films by in situ coordination with 2,3,5,6-tetra(2 0 -pyridyl)pyrazine and 1-octadecanol in pure and mixed Langmuir monolayers

a b s t r a c t The in situ complexation between 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) molecules and europium ions at the air-liquid interface by means of mixed 1-octadecanol Langmuir films is reported. These films were transferred to solid supports by means of the Langmuir-Blodgett (LB) technique. The EDS maps attested the homogeneity of the LB films as well as the presence of the europium ions. The mixed alcohol/tppz LB film contained a larger amount of europium ions as compared to the pure octadecanol LB film. This work reports the production of a thin luminescent Eu 3 þ film containing europium ions using only alcohol molecules as ligands-an unexpected result, since it is well known that there is an occurrence of non-radiative deactivation of excited europium by hydroxyl groups. Europium ion multiple binding sites were detected from lifetime decay measurements of these films in the presence of tppz molecules

Interaction of horseradish peroxidase with Langmuir monolayers of phospholipids

The method employed to incorporate guest molecules onto phospholipid Langmuir monolayers plays an important role in the interaction between the monolayer and the guest molecules. In this paper, we show that for the interaction between horseradish peroxidase (HRP) and a monolayer of dipalmitoylphosphatidylglycerol (DPPG) does depend on the method of HRP incorporation. The surface pressure isotherms of the mixed DPPG/HRP monolayers, for instance, were less expanded when the two materials were co-spread than in the case where HRP was injected into the subphase. Therefore, the method for incorporation affected not only the penetration of HRP but also the changes in molecular packing caused to the DPPG monolayer. With experiments with the monolayer on a pendant drop, we observed that the incorporation of HRP affects the dynamic elasticity of the DPPG monolayer, on a way that varies with the surface pressure. At low pressures, HRP causes the monolayer to be more rigid, while the converse is true for surface pressures above 8 mN/m. Taken all the results together, we conclude that HRP is more efficiently incorporated if injected into the subphase on which a DPPG monolayer had been spread and that the interaction between HRP and DPPG is maintained even at high surface pressures. This is promising for the possible transfer of mixed films onto solid substrates and for applications in biosensors and drug delivery systems. (c) 2008 Elsevier B.V. All rights reserved

Formation of thin luminescent Eu3+-LB films by in situ coordination with 2,3,5,6-tetra(2 '-pyridyl)pyrazine and 1-octadecanol in pure and mixed Langmuir monolayers

The in situ complexation between 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) molecules and europium ions at the air-liquid interface by means of mixed 1-octadecanol Langmuir films is reported. These films were transferred to solid supports by means of the Langmuir-Blodgett (LB) technique. The EDS maps attested the homogeneity of the LB films as well as the presence of the europium ions. The mixed alcohol/tppz LB film contained a larger amount of europium ions as compared to the pure octadecanol LB film. This work reports the production of a thin luminescent Eu3+ film containing europium ions using only alcohol molecules as ligands an unexpected result, since it is well known that there is an occurrence of non-radiative deactivation of excited europium by hydroxyl groups. Europium ion multiple binding sites were detected from lifetime decay measurements of these films in the presence of tppz molecules. (C) 2012 Elsevier B.V. All rights reserved.CAPESCNPq/inct-INAMIFAPES