scispace - formally typeset
Search or ask a question
Author

Fabrício Mezzomo Collares

Other affiliations: University of Rio Grande
Bio: Fabrício Mezzomo Collares is an academic researcher from Universidade Federal do Rio Grande do Sul. The author has contributed to research in topics: Adhesive & Bond strength. The author has an hindex of 23, co-authored 191 publications receiving 1843 citations. Previous affiliations of Fabrício Mezzomo Collares include University of Rio Grande.


Papers
More filters
Journal ArticleDOI
TL;DR: The incorporation of nanostructured hydroxyapatite increases the adhesive properties and may be a promising filler for adhesive resin.

105 citations

Journal ArticleDOI
TL;DR: Higher HEMA content increases dental adhesive resin degradation and the degree of conversion, polymerization rate, ultimate tensile strength, water sorption, and solubility of the adhesive resin blends were determined.
Abstract: PURPOSE To evaluate the effect of variations in 2-hydroxyethyl methacrylate (HEMA) concentrations in an experimental comonomer blend on degree of conversion, water sorption, solubility, and ultimate tensile strength of adhesive resin. MATERIALS AND METHODS The effect of HEMA content (0, 15, 30, and 50%wt - control, G15, G30, and G50 groups, respectively) was tested in an experimental comonomer blend of bis-GMA, bis-EMA, TEG-DMA, and HEMA. The degree of conversion, polymerization rate, ultimate tensile strength, water sorption, and solubility of the adhesive resin blends were determined. RESULTS At 40 s of light activation time, groups G30 and G50 showed a decrease of 30% and 61%, respectively, in degree of conversion compared to control. Water sorption and solubility differed for all groups, and was statistically higher in G50. For ultimate tensile strength, the control and G15 groups showed statistically higher values than the other groups (p < 0.05). CONCLUSION Higher HEMA content increases dental adhesive resin degradation.

81 citations

Journal ArticleDOI
TL;DR: Microhardness and radiopacity increased with higher amounts of Nb(2)O(5), and the particles were able to penetrate into the hybrid layers and may be an alternative for polymer-based biomaterials.

73 citations

Journal ArticleDOI
TL;DR: The internal standard peaks and measurement baseline should be taken into account when using FTIR to calculate the measured degree of conversion (DC) of methacrylate-based resins, especially comonomer blends containing a high degree of monomers that lack aromatic rings.
Abstract: The purpose of this study was to evaluate the influence of the internal standard peak on the measured degree of conversion (DC) for methacrylate-based resins analyzed by Fourier-transform infrared spectroscopy (FTIR). The influence of different baseline measurement methods was also determined. Different blends were prepared, mixing BisGMA/BisEMA and BisGMA/TEGDMA at proportions of 0% to 100%, in weight. Camphoroquinone and ethyl-4-dimethylamino-benzoate were used to permit the light activation of blends. Degree of conversion was evaluated using FTIR equipped with an attenuated total reflectance (ATR) device. Samples were dispensed onto ATR crystal and light activated for 40 s. The DC was calculated by relating the height of the peak 1637 cm-1 to the intensity of different internal standard peaks (1715, 1608, or 1582 cm-1), measured using two different baseline methods, before and after polymerization. Data were compared by ANOVA at 5% significance. The relationship between DC and monomer ratio was obtained by regression analysis. Double-bond conversion ranged from 32.75% to 78.50% for BisGMA/BisEMA blends, and from 32.75% to 76.22% for BisGMA/TEGDMA blends. For the BisGMA/BisEMA blends, the DC showed a linear association with the composition of the comonomer blends, independent of the internal standard peak and baseline method used. In contrast, the trends in DC for BisGMA/TEGDMA blends were different for each method of measurement. The internal standard peaks and measurement baseline should be taken into account when using FTIR to calculate the DC of methacrylate-based resins, especially comonomer blends containing a high degree of monomers that lack aromatic rings.

72 citations

Journal ArticleDOI
TL;DR: The addition of AgNP solutions to Transbond™ XT adhesive primer inhibited S. mutans growth and physicochemical and antimicrobial properties without compromising the chemical and physical properties of the adhesive.
Abstract: Orthodontic treatment with fixed brackets plays a major role on the formation of white spot lesions. Objective This study aimed to incorporate silver nanoparticle solutions (AgNP) in an orthodontic adhesive and evaluate its physicochemical and antimicrobial properties. Material and Methods Silver nanoparticle solutions were added to a commercial adhesive in different concentrations (w/w): 0%, 0.11%, 0.18%, and 0.33%. Shear bond strength (SBS) test was performed after bonding metal brackets to enamel. Raman spectroscopy was used to analyze in situ the degree of conversion (DC) of the adhesive layer. The surface free energy (SFE) was evaluated after the measurement of contact angles. Growth inhibition of Streptococcus mutans in liquid and solid media was determined by colony-forming unit count and inhibition halo, respectively. One-way ANOVA was performed for SBS, DC, SFE, and growth inhibition. Results The incorporation of AgNP solution decreased the SBS (p<0.001) and DC in situ (p<0.001) values. SFE decreased after addition of 0.18% and 0.33% AgNP. Growth inhibition of S. mutans in liquid media was obtained after silver addition (p<0.05). Conclusions The addition of AgNP solutions to Transbond™ XT adhesive primer inhibited S. mutans growth. SBS, DC, and SFE values decreased after incorporation up to 0.33% AgNP solution without compromising the chemical and physical properties of the adhesive.

69 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: An overview on the state‐of‐the‐art antimicrobial nanosized metal‐based compounds is provided, including metal and metal oxide nanoparticles as well as transition metal nanosheets, and their biomedical applications such as catheters, implants, medical delivery systems, tissue engineering, and dentistry.

352 citations

Journal ArticleDOI
TL;DR: This review will examine both the principles and outcomes of techniques to prevent collagen hydrolysis in dentin-resin interfaces, and shows that enzyme inhibition is a promising approach to improve hybrid layer preservation and bond strength durability.

332 citations

01 Jan 1965

319 citations