Avaliação do grau de conversão monomérica de resinas compostas ortodônticas / Degree of conversion evaluation of an orthodontics composite resins

Este estudo avaliou o grau de conversão de uma resina composta utilizada em tratamentos restauradores, Filtek Z 250 - 3M ESPE (Z250), e duas resinas ortodônticas: Orthocem - FGM (OC) e Transbond XT - 3M Unitek (TB) por meio da espectroscopia no infravermelho por transformada de Fourier (FTIR). Para isto, foram confeccionados quinze corpos de prova fotopolimerizados para cada resina. As medidas de grau de conversão foram realizadas imediatamente após a confecção das amostras. Os espectros de absorção no infravermelho foram obtidos num espectrofotômetro Parkin Elmer do Brasil. Os resultados das amostras tiveram sua normalidade aferida por meio do teste Kolmogorov-Smirnov e analisadas pelo teste ANOVA um critério, que demonstrou haver diferença estatística entre os grupos (p<0,05). (AU)

This study evaluated the degree of conversion of a composite resin used in restorative treatments, Filtek Z 250 - 3M ESPE (Z250), and two orthodontic resins: Orthocem - FGM (OC) and Transbond XT - 3M Unitek (TB) by means of infrared spectroscopy Fourier transform (FTIR). For this, fifteen bodies of light cured specimens were fabricated for each resin. Measures of degree of conversion were performed immediately after preparation of the samples. The infrared absorption spectra were obtained on a Parkin Elmer spectrophotometer Brazil. The results of the samples were measured using normality of the Kolmogorov-Smirnov test and analyzed by ANOVA criterion, which showed no statistical difference between groups (p<0,05). (AU)

Effect of etch-and-rinse and self-etching adhesive systems on hardness uniformity of resin cements after glass fiber post cementation.

OBJECTIVE: To evaluate the effects of etch-and-rinse and self-etching adhesive systems on Vickers hardness (VHN) uniformity of dual-cured resin cements after fiber post cementation. METHODS: FIFTY GLASS FIBER POSTS WERE CEMENTED INTO BOVINE ROOTS USING THE FOLLOWING CEMENTING SYSTEMS: Prime&Bond 2.1 Dual Cure and Enforce with light-activation (PBDC-LCEN); Prime&Bond 2.1 and Enforce with light-activation (PB-CLEN); Prime&Bond 2.1 Dual Cure and Enforce without light exposure (PBDC-SCEN); ED Primer and Panavia 21 (ED-SCPN); and Clearfil SE Bond and Panavia 21 (CF-SCPN). The roots were stored in distilled water for 72 h and transversely sectioned into thirds (coronal, medium, and apical). The VHN values of the resin cement layers were measured close to the post and to the dentin wall on the transversely sectioned flat surfaces. The results were analyzed by three-way repeated measures analysis of variance (ANOVA) and Tukey's post-hoc test (pre-set alpha of 5%). RESULTS: Most resin cements presented higher VHN values near the post than near the dentin wall. The ED-SCPN group showed the highest VHN values regardless of the root third, while the self-cured group PBDC-SCEN exhibited the lowest values. The resin cements from the light-activated groups PBDC-LCEN and PB-LCEN showed lower VHN values at the apical third than at the coronal third. The VHN values were not influenced by the root third in self-cured groups PBDC-SCEN, ED-SCPN, and ED-SCPN. CONCLUSION: Depending on the product, bonding agents might promote changes in hardness uniformity of resin cements after post cementation.

Relato de duas técnicas de microabrasão do esmalte para remoção de manchas: discussão de casos clínicos / Report of two microabrasion techniques of enamel to remove stains and discussion

O objetivo deste trabalho foi relatar e discutir por meio da apresentação de casos clínicos a utilização de duas diferentes técnicas de microabrasão do esmalte na remoção de manchas. No primeiro caso clínico, utilizou-se uma mistura de pedra-pomes e ácido fosfórico 37%. No segundo caso clínico, foi utilizado ácido clorídrico 6% e carbeto de silício. Independentemente da técnica selecionada, o sucesso na remoção das manchas está relacionado a corretos diagnósticos. Pode-se concluir que as duas técnicas de microabrasão do esmalte foram capazes de remover as manchas intrínsecas do esmalte, mostrando sua eficácia e, assim, restabelecendo a estética dos elementos dentários envolvidos.

The aim of this study was to report and discuss, through the presentation of clinical cases, the use of two different enamel microabrasion techniques to remove stains. Two techniques were compared between themselves. In the first clinical case used a mixture of pumice and 37% phosphoric acid. In the second case was used 6% cloridric acid and siliceous carbide. Regardless of the technique selected the successful of spots removal is related to a correct diagnosis. It can be concluded that two enamel microabrasion techniques were able to remove intrinsic stains from enamel, demonstrating its effectiveness and thus restoring the esthetics of the teeth involved.