RESUMO
The aim of this study was to investigate the diffusion dynamics of 25% hydrogen peroxide (H2O2) through enamel-dentin layers and to correlate it with dentin's structural alterations. Micro-Raman Spectroscopy (MRS) and Fourier Transform Infrared Photoacoustic Spectroscopy (FTIR-PAS) were used to measure the spectra of specimens before and during the bleaching procedure. H2O2 was applied to the outer surface of human enamel specimens for 60 minutes. MRS measurements were performed on the inner surface of enamel or on the subsurface dentin. In addition, H2O2 diffusion dynamics from outer enamel to dentin, passing through the dentin-enamel junction (DEJ) was obtained with Raman transverse scans. FTIR-PAS spectra were collected on the outer dentin. MRS findings revealed that H2O2 (O-O stretching µ-Raman band) crossed enamel, had a more marked concentration at DEJ, and accumulated in dentin. FTIR-PAS analysis showed that H2O2 modified dentin's organic compounds, observed by the decrease in amides I, II, and III absorption band intensities. In conclusion, H2O2 penetration was demonstrated to be not merely a physical passage through enamel interprismatic spaces into the dentinal tubules. H2O2 diffusion dynamics presented a concentration gradient determined by the chemical affinity of the H2O2 with each specific dental tissue.
Assuntos
Esmalte Dentário/metabolismo , Dentina/metabolismo , Peróxido de Hidrogênio/farmacocinética , Clareadores Dentários/farmacocinética , Adolescente , Adulto , Amidas/análise , Fenômenos Bioquímicos , Carbono/química , Criança , Cor , Esmalte Dentário/efeitos dos fármacos , Dentina/efeitos dos fármacos , Dentina/ultraestrutura , Difusão , Humanos , Hidrogênio/química , Peróxido de Hidrogênio/farmacologia , Microespectrofotometria , Oxigênio/química , Técnicas Fotoacústicas , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Fatores de Tempo , Clareadores Dentários/farmacologia , Adulto JovemRESUMO
PURPOSE: To evaluate the effectiveness of different brands of nail varnish alone or associated with petroleum jelly as surface protectors for glass ionomer cements by determining dye uptake spectrophotometrically. MATERIALS AND METHODS: Three hundred thirty six specimens, 3.0 mm in diameter and 1.0 mm thick, were made with Chelon-Fil (CF) and ChemFil II (CII) and divided into 14 groups for each material. Positive control (A) and negative control (B) specimens were not protected, while experimental specimens were protected with six brands of nail varnish used with and without petroleum jelly. The specimens were immersed in 0.05% methylene blue solution 10 minutes after mixing except for negative control specimens that were immersed in deionized water. RESULTS: Dye uptake (microgram dye/restoration) for CF was: A = 11.3 +/- 3.1; B = 0.0 +/- 0.0 with varnish groups ranging from 0.6 to 2.5 and for CII: A = 12.4 +/- 2.5; B = 0.0 +/- 0.0 with varnish groups ranging from 0.4 to 2.4. The data were analyzed by ANOVA. The dye uptake among the groups was not significantly different (P < 0.01), except for the control group (unprotected cements).
Assuntos
Silicatos de Alumínio/farmacologia , Cosméticos/farmacologia , Cimentos de Ionômeros de Vidro/farmacologia , Pintura , Vaselina/farmacologia , Análise de Variância , Restauração Dentária Permanente , Interações Medicamentosas , Técnica de Diluição de Corante/estatística & dados numéricos , Humanos , Modelos Lineares , Teste de Materiais/métodos , Teste de Materiais/estatística & dados numéricos , Unhas , Propriedades de SuperfícieRESUMO
Aiming to evaluate placement and replacement of dental restorations, a questionnaire has been elaborated and distributed in Clinics of the Operative Dentistry Department, Bauru Dental Scholl--USP, for the students to point out some information about the operatory procedures performed. The analysis of the results made possible the observation that of the 241 restorations achieved, 45.64% were made due to primary caries and 54.36% were replacement of deficient restorations. The reasons for replacement as well as the possible factors responsible for failure of tooth-colored and amalgam restorations are analyzed and discussed.
Assuntos
Cárie Dentária/etiologia , Restauração Dentária Permanente/efeitos adversos , Resinas Compostas , Amálgama Dentário , Cárie Dentária/terapia , Infiltração Dentária , Cimentos de Ionômeros de Vidro , Humanos , Recidiva , Reoperação , Cimento de SilicatoRESUMO
Aiming to evaluate the position variations of the upper canines in individuals with congenital cleft of the lip and palate which interfere in the final result of a prosthesis, we have done an analysis and a measurement of this alterations in casts of 208 patients with complete unilateral cleft before the prosthetic treatment. We have verified in the vertical direction, the infra-version and in the horizontal direction, the mesiodistal deviation of its relation of normal occlusion and the distance in relation to the mid line. The results obtained have become evident a frequent anterolateral openbite in the cleft side, besides a common deviation of the upper mid line, due to the general position of the upper canines on the side side of the cleft to the mesial.