Influence of Pre-Heating Regular Resin Composites and Flowable Composites on Luting Ceramic Veneers with Different Thicknesses

The aim of this study was to evaluate of pre-heating, filler contents and ceramic thickness on film thickness, microshear bond strength, degree of conversion and color change on ceramic veneers. Two experimental composites were prepared (Bis-GMA/UDMA/BisEMA/ TEGDMA), with different amounts of filler (65% or 50%wt) simulating a conventional and a flowable composite. The flowable (F) was used at room temperature and, the conventional either at room temperature (C) or pre-heated (CPH). Disk-shaped ceramics with different thickness (0.4 mm, 0.8 mm, 1.5 mm) were prepared. The film thickness was evaluated according to the ISO 4049 (n=10). The microshear bond strength (n=10) was evaluated in enamel using tubing specimens light-cured through the ceramic veneer. The degree of conversion was evaluated using Raman spectroscopy. The color change of the ceramic restorations (n=10) was evaluated by spectrophotometry. The results were submitted to 2-way ANOVA and Tukey’s post hoc test (a=5%). For the film thickness 1-way ANOVA was used (a=5%). The C presented the thicker film thickness; the CPH produced a similar film thickness in comparison to the F. All composites showed similar microshear bond strength. The degree of conversion of the F was higher than the C and CPH. The degree of conversion of the composites photo-activated through a 0.4 mm was higher than the composites photo-activated through thicker ceramics. The C showed the highest color change, while the CPH showed similar color change to the F. In conclusion, pre-heated conventional composites seem to be a potential alternative to lute ceramic veneers such as the flowable composites

Efeito da fonte de luz na resistência da união entre dente e restauração de compósitos experimentais contendo diferentes fotoiniciadores

O objetivo neste estudo foi avaliar o grau de conversão (DC), taxa de polimerização (Rpmax), dureza knoop e resistência de união do adesivo entre estrutura dental e restauração de resina composta contendo diferentes fotoiniciadores fotoativados por diferentes fontes de luz (LCU). Uma mistura de BisGMA, BisEMA e TEGDMA foi preparada com os seguintes fotoiniciadores: Canforoquinona (CQ), fenil-propanodiona (PPD) ou uma associação de ambos (CQ/PPD) em 65% em massa de partículas silanizadas. As fontes de luz incluíram uma lâmpada halogena XL2500 e dois LEDs: UltraBlueIS e UltraLume5. O perfil da conversão foi investigado com uso de espectroscopia infra-vermelha e a resistência de união avaliada utilizando o teste de push-out em noventa dentes com cavidades preparadas. Depois do teste de push-out, o teste de dureza knoop foi feito no topo e na base das restaurações. O PPD obteve os piores valores de Rpmax independentemente do LCU utilizado. Este também produziu melhor adesividade que CQ quando LEDs LCU foram usados. O grau de conversão depois de 40s de irradiação foi o mesmo para todos os compósitos, com exceção ao PPD fotoativado com XL2500. XL2500 produziu melhores valores de dureza Knoop do que UltraBlueIS quando usado com fotoiniciadores CQ ou CQ/PPD. Devido a melhor adesividade sem comprometimento das propriedades dos compósitos quando fotoativados por LED, PPD pode ser usado como fotoiniciador alternativo.The aim of this study was to evaluate the degree of conversion (DC), rate of polymerization (Rpmax), Knoop hardness (KHN) and bond strength between tooth/restoration of composite resins containing different photo-initiators photo-activated by different light-curing units (LCUs). A mixture of BisGMA, UDMA, BisEMA and TEGDMA was prepared along with the following photo-initiators: camphorquinone (CQ), phenyl-propanedione (PPD) or the association (CQ/PPD) and 65 wt% of silaneted filler particles. The LCUs included a halogen lamp XL2500 and two LEDs: UltraBlueIS and UltraLume5. The conversion profiles during photo-polymerization were investigated using middle-infrared spectroscopy (mid-IR) and the bond strength was evaluated using push-out test in ninety teeth with prepared cavities. After the push-out test, the knoop hardness (KNH) was verified in the top and at the base of the restorations. PPD obtained lower Rpmax values, regardless of the LCU used. It also provided a greater bond strength than CQ when the LEDs LCUs were used. The degree of conversion after 40s of irradiation was the same for all composite resins, except PPD photo-activated for XL2500, which showed lower DC values than CQ and CQ/PPD. In the top and at the base of the restorations, PPD showed the lowest KH values when photo-activated with XL2500. XL2500 produced higher KNH values than UltraBlueIS when used with CQ or CQ/PPD photo-initiators. Because it increased the bond strength without compromising the properties of composite resins when photo-activated by a LED, PPD can be used as an alternative photoinitiator

Influence of the temperature and filler content on film thickness, bond strenght, color changing and degree of conversion of resin composite under ceramic veneers with different thicknesses

Orientador: Mário Alexandre Coelho SinhoretiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo neste estudo foi avaliar o efeito do aumento da temperatura e do conteúdo de carga na espessura de película, resistência de união, alteração de cor e grau de conversão de compósitos resinosos experimentais fotoativados através de facetas cerâmicas com diferentes espessuras. Foram preparados dois compósitos com composições monoméricas idênticas (29% em peso de Bis-GMA, 32,5% em peso de UDMA, 32,5% em peso de BisEMA e 6% em peso de TEGDMA), porém com quantidades de partículas de carga (20% de sílica pirogênica... O resumo poderá ser visualizado no texto completo da tese digitalAbstract: The aim of this study was to evaluate the effect of increasing temperature and filler content on film thickness, microshear bond strength, color change and degree of conversion of experimental resin composites photoactivated through ceramic veneers with different thicknesses. Two composites with identical monomeric compositions (29 wt.% Bis-GMA, 32.5 wt.% UDMA, 32.5 wt.% BisEMA and 6 wt.% TEGDMA) were prepared, but with different amounts of filler particles... The abstract is available with the full electronic documentMestradoMateriais DentariosMestre em Materiais Dentários1590318CAPE

Influence of Pre-Heating Regular Resin Composites and Flowable Composites on Luting Ceramic Veneers with Different Thicknesses

The aim of this study was to evaluate of pre-heating, filler contents and ceramic thickness on film thickness, microshear bond strength, degree of conversion and color change on ceramic veneers. Two experimental composites were prepared (Bis-GMA/UDMA/BisEMA/ TEGDMA), with different amounts of filler (65% or 50%wt) simulating a conventional and a flowable composite. The flowable (F) was used at room temperature and, the conventional either at room temperature (C) or pre-heated (CPH). Disk-shaped ceramics with different thickness (0.4 mm, 0.8 mm, 1.5 mm) were prepared. The film thickness was evaluated according to the ISO 4049 (n=10). The microshear bond strength (n=10) was evaluated in enamel using tubing specimens light-cured through the ceramic veneer. The degree of conversion was evaluated using Raman spectroscopy. The color change of the ceramic restorations (n=10) was evaluated by spectrophotometry. The results were submitted to 2-way ANOVA and Tukey"s post hoc test (a=5%). For the film thickness 1-way ANOVA was used (a=5%). The C presented the thicker film thickness; the CPH produced a similar film thickness in comparison to the F. All composites showed similar microshear bond strength. The degree of conversion of the F was higher than the C and CPH. The degree of conversion of the composites photo-activated through a 0.4 mm was higher than the composites photo-activated through thicker ceramics. The C showed the highest color change, while the CPH showed similar color change to the F. In conclusion, pre-heated conventional composites seem to be a potential alternative to lute ceramic veneers such as the flowable composites

Can phenyl-propanedione influence Knoop hardness, rate of polymerization and bond strength of resin composite restorations?

Made available in DSpace on 2019-09-12T16:53:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2011Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Objectives: The aim of this study was to evaluate the degree of conversion (DC), rate of polymerization (R(p)(max)), Knoop hardness (KHN) and bond strength between tooth/restoration of composite resins containing different photo-initiators photo-activated by different light-curing units (LCUs). Materials and methods: A mixture of BisGMA, UDMA, BisEMA and TEGDMA was prepared along with the following photo-initiators: camphorquinone (CQ), phenyl-propanedione (PPD) or the association (CQ/PPD) and 65 wt% of silanated filler particles. The LCUs included a halogen lamp XL 2500 and two LEDs: UltraBlueIS and UltraLume5. The conversion profiles during photo-polymerization were investigated using middle-infrared spectroscopy (mid-IR). Bond strength was evaluated using push-out test in ninety teeth with prepared cavities. Before the push-out test, Knoop hardness (KH) was verified in the top and at the base of the restorations. Results: PPD obtained lower R(p)(max) values, regardless of the LCU used. It also provided a greater bond strength than CQ when the LEDs LCUs were used. The degree of conversion after 40 s of irradiation was the same for all composite resins, except PPD photo-activated for XL 2500, which showed lower DC values than CQ and CQ/PPD. In the top and at the base of the restorations, PPD showed the lowest KH values when photo-activated with XL 2500. XL 2500 produced higher KH values than UltraBlueIS when used with CQ or CQ/PPD photo-initiators. Conclusion: Because it increased the bond strength without compromising the properties of composite resins when photo-activated by an LED, PPD can be used as an alternative photo-initiator. (C) 2011 Elsevier Ltd. All rights reserved.[Brandt, William Cunha] Universidade de Taubaté (Unitau), , Sch Dent, Dept Prosthodont, BR-12020330 Taubate, SP, Brazil[Tomaselli, Lucas de Oliveira; Correr-Sobrinho, Lourenco; Coelho Sinhoreti, Mario Alexandre] Univ Estadual Campinas, Dept Restorat Dent, Dent Mat Div, Piracicaba Dent Sch, BR-13414903 Piracicaba, SP, Brazi

Accuracy Of Partially Edentulous Arch Impressions Obtained From Different Alginates And Storage Times

This study aimed to assess the dimensional accuracy of five commercial alginates verified in stone casts. Methods: Each alginate impression (Cavex ColorChange, Cavex Holland BV; Jeltrate Plus, Dentsply; Hydrogum, Zhermack; Kromopan 100, Lascod; Ezact Kromm, Vigodent) was performed on partially edentulous standard stainless steel mandibular arch cast with reference points on teeth 33, 43, 37 and 47. On the stainless steel cast, the anteroposterior (33-37 and 43-47) and transverse (33-43 and 37-47) distances were measured in a stereomicroscope at 30x magnification and 0.5 ?m accuracy. The distances between these points were measured three times, obtaining an average, which was analyzed statistically and compared with the distances obtained from the stone casts. For each alginate the casts were poured gypsum (n = 5) immediately and after a period of 1, 2, 3 and 5 days of the impression procedure. Results: The dimensional accuracy values of stone and stainless steel casts were analyzed statistically by two-way ANOVA and Tukey's test (?=0.05). The results showed significant differences between the alginates; however, no differences in dimensional accuracy were found among the different storage times of alginate impression. Conclusions: It can be concluded that the alginate impressions can be stored for up to 5 days.15