Resin-modified glass ionomer containing calcium glycerophosphate: physico-mechanical properties and enamel demineralization

Sources of calcium and phosphate have been added to dental restorative materials to improve their anticaries effect. Objective: This study evaluated the effect of adding calcium glycerophosphate (CaGP) to resin-modified glass ionomer cement (RMGIC) on the physico-mechanical properties, ion release, and enamel demineralization. Material and Methods: Specimens were fabricated for each experimental group: RMGIC without CaGP (Control), RMGIC with 1, 3 and 9% CaGP. To determine the release of fluoride (F), calcium (Ca) and phosphorus (P), six specimens were immersed in demineralization and remineralization solutions for 15 days. In another experimental trial, the following physico-mechanical properties were evaluated at time intervals of 1 and 7 days after fabrication: compressive strength (n=12), diametral tensile strength (n=12), surface hardness of material (n=6) and the degree of conversion of monomers (n=8). To study enamel demineralization, specimens (n=12) were attached to enamel blocks and submitted to pH-cycling. Subsequently, surface and cross-sectional hardness and the concentration of F, Ca and P in enamel were determined. Results: The addition of CaGP to RMGIC led to higher mean release of F, Ca and P when compared with control (p<0.001). Mechanical properties were within the range of those of the ionomer cements after addition of 1% and 3% CaGP. The degree of conversion did not differ between groups at the 1st and the 7th day (p>0.439). The addition of 3% and 9% CaGP reduced mineral loss and increased F, Ca and P in the enamel when compared with control (p<0.05). Conclusion: The addition of 3% CaGP in RMGIC increased the release of F, P and Ca, reduced enamel demineralization, and maintained the physico-mechanical properties within the parameters for this material

Novel pulp capping material based on sodium trimetaphosphate: synthesis, characterization, and antimicrobial properties

Objectives: To evaluate the mechanical, physicochemical, and antimicrobial properties of four different formulations containing micro- or nanoparticles of sodium trimetaphosphate (mTMP and nTMP, respectively). Methodology: Four experimental groups were used in this investigation: two mTMP groups and two nTMP groups, each containing zirconium oxide (ZrO2), and solution containing either chitosan or titanium oxide (TiO2) nanoparticles (NPs). Setting time, compression resistance, and radiopacity were estimated. The agar diffusion test was used to assess the antimicrobial activity of the formulations against five different microbial strains: Streptococcus mutans, Lactobacillus casei, Actinomyces israelii, Candida albicans, and Enterococcus faecalis. Parametric and nonparametric tests were performed after evaluating homoscedasticity data (p<0.05). Results: From the properties evaluated, nTMP cements required less setting time and showed greater resistance to compression. Cements containing TiO2 showed greater radiopacity for both nTMP and mTMP. All four cement formulations showed antimicrobial activity against S. mutans and L. casei.  Conclusion: Formulations containing nTMP have shorter setting times and higher compressive strength, and those with TiO2 nanoparticles showed antimicrobial activities. Clinical relevance: The cement containing nTMP, ZrO2, and TiO2 could be an alternative material for protecting the pulp complex

Influence of the Vehicle on the Tissue Reaction and Biomineralization of Fast Endodontic Cement

Objective: To investigate the tissue response and the biomineralization ability of CER prepared with epoxy resin or water compared to Mineral Trioxide Aggregate (MTA). Material and Methods: Polyethylene tubes containing materials or empty tubes for control were inserted into the subcutaneous tissues of 30 rats. After 7, 15, 30, 60, and 90 days, the rats were killed and the tubes were removed for analysis using hematoxylin-eosin staining, von Kossa staining, and under polarized light. Inflammation was graded through a score system; the thickness of the fibrous capsule was classified as thin or thick; the biomineralization ability was recorded as present or absent. The results were statistically analyzed using the Kruskal-Wallis test (p<0.05). Results: Histologic analysis performed after 7 and 15 days for CER prepared with epoxy resin or water and for MTA showed moderate inflammation and a thick fibrous capsule (p>0.05). After 30, 60, and 90 days, mild inflammation, and a thin fibrous capsule were observed in all groups (p>0.05). Conclusion: All materials had structures positive for von Kossa and birefringent to polarized light. CER epoxy resin showed biocompatibility and biomineralization similar to CER water and MTA

Confecção de espelhos de saída de germânio (Ge) para laser de CO2

Orientador: Zoraide Primerano ArguelloDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb WataghinResumo: O presente trabalho desenvolve todo procedimento a ser seguido para a confecção de espelhos para laser de CO2 de baixa potência. O material utilizado como substrato é o Germânio. Os filmes finos evaporados neste substrato para obtenção das propriedades óticas (Reflexão e Transmissão) imposta pelo Laser projetado foram Sulfeto de Zinco (dielétrico) e Alumínio (metálico). Na parte de orientação de monocristais é desenvolvido uma técnica de agilização do método de Laue de retrocesso, através da utilização de microcomputadorAbstract: Not informed.MestradoFísicaMestre em Físic

Espectroscopia à alta resolução do 13CD3OH

Orientador: Daniel PereiraTese (doutorado) - Universidade Estadual de Campinas Instituto de Fisica Gleb WataghinResumo: Neste trabalho realizamos uma investigação sistemática do modo vibracional de estiramento C-O, da espécie isotópica 13CD3OH. Os objetivos básicos foram: geração de novas linhas laser IVL; aquisição de dados de absorção IV através de técnicas de espectroscopia à Transformada de Fourier e Fotoacústica; análise dos dados experimentais usando modelos de vibração e rotação para a determinação de números quânticos de níveis e autovalores de energia associados à transições IV e IVL. Através da técnica de espectroscopia à Transformada de Fourier, espectros contínuos à resolução 0.12 e 4 x 10-3 cm-1, na região de 920 a 1070 cm-1, foram obtidos. Destes espectros foi possível determinarmos: 45 transições de absorção IV em boa coincidência com o espectro de emissão do laser a CO2; e O valor do número quântico J dos multipletos principais (n=O) dos ramos P e R do modo de estiramento C-O. Como conseqüência do bombeamento óptico da molécula, pela primeira vez utilizando um laser a CO2 em guia de onda com 290 MHz de largura de ganho como fonte de bombeamento, observamos e caracterizamos 96 novas emissões laser IVL. Para cada linha, realizamos medidas de comprimento de onda, polarização e intensidade relativa, pressão, e off-set. A freqüência de 13 linhas laser IVL deste isótopo, foram medidas através da técnica de detecção heterodina. Realizamos também uma investigação fotoacústica, utilizando a cavidade laser IVL, como uma cela fotoacústica. Como conseqüência observamos 108 linhas de absorção e para cada uma delas, medimos o off-set e intensidade relativa. Além disso, apresentamos um "ATLAS" de espectros de absorção fotoacústica em torno de linhas de emissão do laser a CO2. Por meio de uma comparação direta entre dados experimentais e um espectro calculado, gerado pelo modelo vibro-roto-torcional para moléculas tipo metanol, identificamos os números quânticos dos níveis de energia envolvidos em 16 transições de emissão laser IVL e em 7 transições de absorção IV relacionadas, bem como determinamos os autovalores de energia. Os resultados da análise do espectro à Transformada de Fourier foram fundamentais para algumas identificaçõesAbstract: In this work we have performed a systematic investigation on the C-O stretching vibrational band of the 13CD3OH molecule. The basic purposes of ours study were: the generation of new FIR laser lines; acquisition of IR absorption data by Fourier Transform and Optoacoustic spectroscopy techniques; and a spectroscopic analysis of the experimental data, using vibration and rotation models for the determination of quantum numbers and energy eigenvalues associated with IR and FIR transitions. By using Fourier Transform spectroscopy, continuous spectra were obtained in the region from 920 to 1070 cm-l, at instrumental resolution of 0.12 cm-l and 4 x 10-3 cm-l. From these spectra it was possible to find 45 IR absorption transitions in good coincidence with the CO2 laser emission spectra and to determine the J quantum numbers of the main multiplets (n=O) in the P and R branches of the C-O stretching mode. As a consequence of the optical pumping of this molecule, using, for the first time, a 290 MHz tunability WG CO2 laser, we observed 96 new FIR laser lines. For each line we performed wavelenght, polarization, relative intensity, pressure and off-set measurements. The frequency of 13 lines were measured by a heterodyne detection technique. An optoacoustic investigation using the FIR laser cavity itself as an optoacoustic cell was also carried out. From this, we observed 108 absorption lines which had their off-set and relative intensity measured. Furthermore, we present an "atlas" of the optoacoustic absorption spectra around the CO2 laser emission lines. By a direct comparison between the experimental data and the calculated spectra, obtained from the vibro-roto-torsional model for methanol-type molecules, we identified the quantum numbers of the energy levels involved in 16 FIR laser transitions and in 7 related IR absorption transitions, and we determined the energy eigenvalues. The results obtained from Fourier Transform spectra analysis were fundamental for same assignmentsDoutoradoFísicaDoutor em Ciência