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Seung-ryong Ha - One of the best experts on this subject based on the ideXlab platform.

  • Improving shear bond strength of temporary crown and fixed dental prosthesis resins by surface treatments
    Journal of Materials Science, 2016
    Co-Authors: Seung-ryong Ha
    Abstract:

    This study evaluated the effect of surface treatments on the bond strength of repaired temporary resins. One-hundred flat-surfaced cylindrical specimens (Ø 7 mm × 12 mm) of each temporary resin (2 bis-acryl resins and 2 Polymethyl-Methacrylates) were prepared. The specimens were randomly divided into 10 groups ( n  = 10), according to the types of surface treatments: untreated, adhesive treated, silanated, silane + adhesive treated, hydrofluoric acid etched, laser treated, sandblasted, sandblasting + adhesive treated, sandblasting + silanated, and tribochemical silica coating + silanated. Each resin material of the same brand with cylindrical shape (Ø 3 mm × 3 mm) was polymerized onto the resin surfaces, and specimens were stored for 24 h in distilled water. The shear bond strengths were measured and failure modes were examined. All data were analyzed with a one-way ANOVA and multiple comparison Scheffé post hoc test ( α  = 0.05). For bis-acryl resins, the highest shear bond strength was observed in sandblasted group and the lowest was observed in the control group. Results show that the repair bond strength was improved for bis-acryl resin by 23 % than that of the control group due to the increase in surface roughness by sandblasting. However, chemical treatment did not improve repair bond strength. The surface treatment of bis-acryl resins with sandblasting seems to be promising for the improvement of repair bond strength.

Marco W. Fraaije - One of the best experts on this subject based on the ideXlab platform.

Dantas, Lucas Costa De Medeiros - One of the best experts on this subject based on the ideXlab platform.

  • Efeito das técnicas de finalização e manipulação de resina acrílica na adesão bacteriana e rugosidade superficial
    Universidade Federal de Uberlândia, 2011
    Co-Authors: Dantas, Lucas Costa De Medeiros
    Abstract:

    A formação do biofilme e o acúmulo bacteriano em materiais odontológicos podem causar o desenvolvimento de inflamação gengival e cáries secundárias. Objetivos: A proposição deste estudo foi examinar o efeito de diferentes finalizações superficiais na rugosidade superficial e adesão de S. sanguinis na resina acrílica. Materiais e Métodos: 50 espécimes (6mm de diâmetro) foram divididos em 5 grupos (n=10), de acordo com técnica de confecção e acabamento ou polimento, L (Proporção recomendada pelo fabricante (3:1) e polido laboratorialmente), NF (Técnica de Nealon e acabamento), NP (Técnica de Nealon e polimento manual), MF (3:1 e acabamento) e MP (3:1 e polimento manual). Cinco amostras representativas foram submetidas ao teste de adesão bacteriana e contagem das unidades formadoras de colônia (UFC) em microscopia eletrônica de varredura (MEV), em duas amostras foram observadas a topografia superficial, outras três amostras foram submetidas ao teste de rugosidade superficial em rugosímetro para obtenção da rugosidade média (Ra). Dados foram comparados usando ANOVA one-way e classificadas pelo teste de Tukey. Resultados: As médias obtidas para contagem de UFCs: L (controle) 1,56±0,62a; MP 5,36±2,08ab; NP 4,96±1,92ab; MF 7,36±2,45b e NF 19,6±3,05c. As médias para os valore de Ra (μm): L (controle) 0,09±0,01a; MP 0,52±0,05b; NP 0,61±0,08b; MF 2,69±0,12c e NF 3,23±0,15d (letras diferentes significam diferença estatística). Conclusão: Foi possível concluir que o polimento laboratorial da resina diminuiu a adesão bacteriana e a rugosidade superficial, portanto levando a um melhor prognóstico em termos de saúde periodontal e redução de cáries secundárias.The formation of biofilm and bacterial accumulation on dental materials may lead to the development of gingival inflammation and secondary caries. In dentistry different techniques can be used to make provisional restorations using acrylic Polymethyl Methacrylates (PMMA). The purpose of this study was to examine the effect of different surface finishing and polishing on surface roughness and the adhesion of S. sanguinis bacteria to PMMA. Fifty specimens (6mm diameter) were divided into 5 groups (n=5), following fabrication techniques and surface finishing and polishing: L (laboratorial fabrication and polishing), NF (Nealon technique and surface finishing), NP (Nealon technique and surface polishing), MF (technique recommended by manufacture and surface finishing), MP (technique recommended by manufacture and surface polishing). Five representative specimens were submitted to bacterial adhesion test and measured by counting with SEM images, two were observed the surface topography also by SEM images, other three were submitted to roughness test. Data were compared by ANOVA. The mean results of sample bacterial counts: NF: 19.6c; MP: 5.36ab; NP: 4.96ab; MF: 7.36b and L (control): 1.56a. The mean results of surface roughness: NF: 3.23d; MP: 0.52b; NP: 0.60b; MF: 2.69c and L (control): 0.07a (different letters means statistical significance difference). It was conclude that the laboratory processing of PMMA may decrease S.sanguinis adhesion and surface roughness, thus has a better prognosis in terms of periodontal health and less secondary caries

  • Efeito das técnicas de finalização e manipulação de resina acrílica na adesão bacteriana e rugosidade superficial
    'EDUFU - Editora da Universidade Federal de Uberlandia', 2011
    Co-Authors: Dantas, Lucas Costa De Medeiros
    Abstract:

    The formation of biofilm and bacterial accumulation on dental materials may lead to the development of gingival inflammation and secondary caries. In dentistry different techniques can be used to make provisional restorations using acrylic Polymethyl Methacrylates (PMMA). The purpose of this study was to examine the effect of different surface finishing and polishing on surface roughness and the adhesion of S. sanguinis bacteria to PMMA. Fifty specimens (6mm diameter) were divided into 5 groups (n=5), following fabrication techniques and surface finishing and polishing: L (laboratorial fabrication and polishing), NF (Nealon technique and surface finishing), NP (Nealon technique and surface polishing), MF (technique recommended by manufacture and surface finishing), MP (technique recommended by manufacture and surface polishing). Five representative specimens were submitted to bacterial adhesion test and measured by counting with SEM images, two were observed the surface topography also by SEM images, other three were submitted to roughness test. Data were compared by ANOVA. The mean results of sample bacterial counts: NF: 19.6c; MP: 5.36ab; NP: 4.96ab; MF: 7.36b and L (control): 1.56a. The mean results of surface roughness: NF: 3.23d; MP: 0.52b; NP: 0.60b; MF: 2.69c and L (control): 0.07a (different letters means statistical significance difference). It was conclude that the laboratory processing of PMMA may decrease S.sanguinis adhesion and surface roughness, thus has a better prognosis in terms of periodontal health and less secondary caries.Mestre em OdontologiaA formação do biofilme e o acúmulo bacteriano em materiais odontológicos podem causar o desenvolvimento de inflamação gengival e cáries secundárias. Objetivos: A proposição deste estudo foi examinar o efeito de diferentes finalizações superficiais na rugosidade superficial e adesão de S. sanguinis na resina acrílica. Materiais e Métodos: 50 espécimes (6mm de diâmetro) foram divididos em 5 grupos (n=10), de acordo com técnica de confecção e acabamento ou polimento, L (Proporção recomendada pelo fabricante (3:1) e polido laboratorialmente), NF (Técnica de Nealon e acabamento), NP (Técnica de Nealon e polimento manual), MF (3:1 e acabamento) e MP (3:1 e polimento manual). Cinco amostras representativas foram submetidas ao teste de adesão bacteriana e contagem das unidades formadoras de colônia (UFC) em microscopia eletrônica de varredura (MEV), em duas amostras foram observadas a topografia superficial, outras três amostras foram submetidas ao teste de rugosidade superficial em rugosímetro para obtenção da rugosidade média (Ra). Dados foram comparados usando ANOVA one-way e classificadas pelo teste de Tukey. Resultados: As médias obtidas para contagem de UFCs: L (controle) 1,56±0,62a; MP 5,36±2,08ab; NP 4,96±1,92ab; MF 7,36±2,45b e NF 19,6±3,05c. As médias para os valore de Ra (μm): L (controle) 0,09±0,01a; MP 0,52±0,05b; NP 0,61±0,08b; MF 2,69±0,12c e NF 3,23±0,15d (letras diferentes significam diferença estatística). Conclusão: Foi possível concluir que o polimento laboratorial da resina diminuiu a adesão bacteriana e a rugosidade superficial, portanto levando a um melhor prognóstico em termos de saúde periodontal e redução de cáries secundárias

Hugo L. Van Beek - One of the best experts on this subject based on the ideXlab platform.

R P Kusy - One of the best experts on this subject based on the ideXlab platform.

  • effect of methacrylic acid methyl methacrylate monomer ratios on polymerization rates and properties of Polymethyl Methacrylates
    Journal of Biomedical Materials Research, 1997
    Co-Authors: T Chen, R P Kusy
    Abstract:

    Five binary formulations were prepared from methyl methacrylate (MMA) and methacrylic acid (MAA) monomers, and six ternary formulations were prepared from polysols of 30% wt Polymethyl methacrylate (PMMA)/MMA and MAA. Using thermal analyses (DSC and TGA) the polymerization kinetics, condition of postcuring, relative amount of residual monomers, and glass transition temperature (Tg) were determined. From bar-shaped samples, 25 × 5 × 0.9 mm in dimensions, mechanical properties [flexural moduli (E) and maximum strengths (σ)] were measured in three-point bending. Polymerization kinetics of binary formulations improved over pure PMMA (from 15 to 4 min) as a result of over a 60-fold increase in propagation-to-termination constants (Kp/Kt) of MAA/MMA. The further addition of PMMA increased the viscosity, slowed down termination, and, consequently, improved the polymerization kinetics twofold. These enhancements occurred without a substantive change in the Tg of the ternary system (ca. 107°C) over pure PMMA (ca. 112°C). Moreover, the Es of the four ternary formulations averaged 2.94 GPa, which was comparable with many values reported in the literature. In contrast the σs of these same formulations averaged 97 MPa, which was about 25% better than earlier investigations of pure acrylic. When a thermoplastic material is required for pultruding profiles that cure fast and have good thermal-mechanical properties, ternaries of PMMA/MMA/MAA should be considered. © 1997 John Wiley & Sons, Inc.