Influence of the photoinitiator system on physical-chemical properties of experimental self-adhesive flowable composites

Orientadores: Mario Alexandre Coelho Sinhoreti, Ana Rosa Costa CorrerDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo neste estudo foi determinar a influência de diferentes sistemas fotoiniciadores sobre a taxa de polimerização, grau de conversão, saturação de amarelo e absorção de água de resinas compostas experimentais fluidas autoadesivas. A matriz orgânica das resinas compostas foi formulada utilizando os monômeros bisfenol glicidil dimetacrilato (BisGMA) e trietilenoglicol dimetacrilato (TEGDMA) (50/50% em peso). Para as resinas compostas autoadesivas foi acrescentado o monômero Bis[2-(metacriloiloxi)etil] fosfato (2MP) (40% em peso). Os fotoiniciadores testados foram canforquinona (CQ), óxido mono-alquil fosfínico (TPO) e óxido bis-alquil fosfínico (BAPO). As combinações CQ+TPO e CQ+BAPO também foram testadas. Uma amina terciária (EDMAB) foi usada como molécula co-iniciadora para todos os sistemas que continham CQ na formulação. Foi adicionado a estes sistemas 45% em peso de partículas de carga inorgânica silanizadas (BaAlSi 2 ?m; BaAlSi 0,7 ?m; SiO? 50nm). A taxa máxima de polimerização (n=3) e o grau de conversão foram avaliados por espectroscopia de infra-vermelho próximo (NIR). Para análise da saturação de amarelo (n=5) foi utilizado um espectrofotômetro empregando o eixo b* do parâmetro CIELab. As leituras foram realizadas imediatamente após a fotoativação. A absorção de água (n=5) foi avaliada por variação de massa após o armazenamento em água por 30 dias. Os resultados foram analisados usando ANOVA 2 fatores e teste de Tukey (?=0,05). BAPO foi o fotoiniciador com maior taxa de polimerização em ambas as resinas compostas. As resinas compostas autoadesivas apresentaram menor taxa de polimerização quando CQ+EDMAB foi usado e não houve diferença estatística em relação às convencionais quando TPO, CQ+EDMAB+TPO e CQ+EDMAB+BAPO foram usados. As resinas compostas autoadesivas apresentaram grau de conversão maior do que as convencionais quando fotoiniciadores alternativos foram usados. As resinas compostas autoadesivas, exceto as que possuíam somente BAPO apresentaram maior amarelamento para todos os fotoiniciadores. No entanto, BAPO foi o fotoiniciador que provocou o maior amarelamento tanto nas resinas compostas convencionais quanto nas autoadesivas. As resinas compostas autoadesivas absorveram mais água, qualquer que fosse o sistema fotoiniciador usado. Conclui-se que o grupo com CQ+EDMAB+TPO apresentou os resultados mais satisfatórios para as resinas compostas autoadesivas. No entanto, as resinas compostas autoadesivas ficaram mais amarelas após a fotopolimerização e absorveram mais água em relação aos grupos controleAbstract: The aim in this study was to determine the influence of different photoinitiators systems on polymerization rate, degree of conversion, degree of yellowing and water absorption of self-adhesive flowable composites experimental. The organic matrixes of composite resins were formulated using the monomers bisphenol-glycidyl dimethacrylate (BisGMA) and triethyleneglycol dimethacrylate (TEGDMA) (50/50% weight). For self-adhesive composites, bis-2-methacyloyloxy-ethyl phosphate (2MP) (40% weight) was added in the formulation. The photoinitiators tested were camphorquinone (CQ); diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (TPO); phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO). The combinations of CQ+TPO and CQ+BAPO were also tested. Ethyl-4-dimethylamino benzoate (EDMAB) was used as co-initiator for those systems containing CQ in the formulation. 45% percent by weigth of silanized inorganic particles (BaAlSi 2 ?m; BaAlSi 0.7 ?m; SiO2 50nm) were added. The maximum rate of polymerization (n=3) and degree of conversion were determined using near¿infrared (NIR) spectroscopy. For analyze the yellowing effect (n=5) was used a spectrophotometer employing the axis b* of CIELab parameter. Readings were taken immediately after curing. The water absorption (n=5) was evaluated by weight change after storage in water for 30 days. Outcomes were analyzed using two-way ANOVA and Tukey's test (?=0.05). BAPO was the photoinitiator with higher rate polymerization of conventional and self-adhesive composites. Self-adhesive composite shows lower rate polymerization when CQ+EDMAB was used. There was not statistical difference between conventional and self-adhesive composite when TPO, CQ+EDMAB+TPO and CQ+EDMAB+BAPO were used. Self-adhesive composites promoted high degree of conversion when alternative photoinitiators were used. The self-adhesive composites promoted higher degree of yellowing for all photoinitiators, except BAPO. However, BAPO showed higher yellowing effect of conventional and self-adhesive composites. The self-adhesive composites promoted higher water absorption for all photoinitiators systems. It is concluded that the group with CQ+EDMAB+TPO showed the most satisfactory results of self-adhesive composites. However, self-adhesive composites were more yellow after photopolymerization, and they absorbed more water than the control groupsMestradoMateriais DentariosMestre em Materiais DentáriosCAPE

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

Effect of adhesive-monomers and photoinitiator on C = C conversion and color stability of model self-adhesive flowable composites

Made available in DSpace on 2019-09-12T16:53:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2018Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação Nacional de Desenvolvimento do Ensino Superior Particular (Funadesp)The aim of this study was to determine the influence of the monomer type and photoinitiator systems on the degree of C = C conversion and color stability of model self-adhesive flowable composites (SAFCs). Three sets of flowable composites were formulated varying the monomer type: set 1 (control), with bisphenol-A glycidyl methacrylate and triethylene glycol dimethacrylate (BisGMA/TEGDMA) at 50/50 wt%; set 2, with BisGMA/TEGDMA/bis[2(methacryloyloxy)ethyl]phosphate (2MP) at 30/30/40 wt%; and set 3, with BisGMA/TEGDMA/4-ethyl-methacryloxy-trimetilato anhydride (4-META) at 30/30/40 wt%. For each set, different initiator systems were added: camphorquinone (CQ) + ethyl-4-dimethylamino benzoate (EDMAB); diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (TPO); phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO); and the combinations CQ + EDMAB + TPO and CQ + EDMAB + BAPO. Degree of C = C conversion was determined by Fourier-transformed infrared spectroscopy with an attenuated total reflectance device (ATR-FTIR). The color stability was determined by CIE infinity color difference formula (Delta E-infinity*), after water (T-1) and coffee (T-2) storages for 30 days. Data was submitted to two-way analysis of variance (ANOVA) followed by Student-Newman-Keuls test (alpha = 0.05). Degree of conversion and color stability were dependent on the resin matrix composition and the photoinitiator system. The 2MP-based set showed the highest DC, but also the poorest color stability. For the 4-META-base set, TPO and BAPO produced the highest degree of C = C conversion. The use of BAPO produced the best color stability for the acidic-monomer-based sets.[Monteiro, Alessandra Amaral; Cavalcante, Larissa Maria; Schneider, Luis Felipe J.] Univ Veiga de Almeida, Sch Dent, Nucleus Dent Biomat Res, Rio De Janeiro, RJ, Brazil[Salgado, Vinicius Esteves; Cavalcante, Larissa Maria] Univ Salgado de Oliveira, Sch Dent, Niteroi, RI, Brazil[Vitti, Rafael Pino] Universidade de Taubaté (Unitau), Dept Prosthodont, Sch Dent[Loureiro Bertolo, Marcus Vinicius] Univ Estadual Campinas, Piracicaba Dent Sch, Dent Mat Area, Piracicaba, Brazil[Salgado, Vinicius Esteves; Cavalcante, Larissa Maria; Schneider, Luis Felipe J.] Fed Fluminense Univ, Sch Dent, Niteroi, RJ, Brazi

Influence Of Photoinitiator System On Physical-chemical Properties Of Experimental Self-adhesive Composites

The aim of this study was to determine the influence of photoinitiator systems on physical-chemical properties of flowable composites. Conventional (CFC), composed by bisphenol-glycidyl dimethacrylate (BisGMA)+triethyleneglycol dimethacrylate (TEGDMA), and self-adhesive (SAFC), composed by BisGMA+TEDGMA+bis{2-(methacryloyloxy) ethyl} phosphate (2MP), flowable composites were developed. Five photoinitiator systems were tested: camphorquinone (CQ), ethyl-4-dimethylaminobenzoate (EDMAB), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), phenylbis (2,4,6-trimethylbenzoyl)phosphine oxide (BAPO), CQ+EDMAB+TPO and CQ+EDMAB+BAPO. A two-peak LED was used; degree of conversion (DC) and the maximum polymerization rate (RPmax) were determined by near infrared spectroscopy. For the yellowing degree a spectrophotometer was used. Water sorption (Wsp) was obtained after 30 days of water storage (n=5). Data were submitted to two-way analysis of variance and Tukey’s test (a=0.05). BAPO presented the highest DC and RPmax values for both series. SAFCs presented lower DC and RPmax for CQ+EDMAB-based materials. Greater yellowing was observed for SAFCs compared with CFCs, except for BAPO. Greater Wsp was observed for SAFCs compared with CFCs. The photoinitiator did not influence Wsp for CFCs, but TPO and BAPO presented the highest Wsp in SAFCs. The photoinitiator system affected differently the physical-chemical properties of CFCs and SAFCs.281353

O uso do gel de glicerina melhora a estabilidade de cor de resinas compostas?

Resumo Introdução A camada superficial de resina composta não polimerizada, em função da presença do oxigênio, ocasiona problemas clínicos, como alteração de cor por absorção de pigmentos. Objetivo Determinar o efeito de diferentes técnicas usadas no controle da formação da camada de dispersão sobre as propriedades ópticas de uma resina composta comercial. Material e método Espécimes foram produzidos com a resina composta Estelite Sigma. A fotoativação foi conduzida com uma fonte de luz LED Bluephase G2 (1.200 mW/cm2 por 40 s). Os grupos foram determinados em função de três técnicas distintas: 1) sem tratamento (controle); 2) fotoativação com gel de glicerina; 3) polimento com lixa abrasiva após a fotoativação. A estabilidade de cor (ΔE) e o parâmetro de translucidez foram determinados pelo método de espectroscopia de reflectância (Easyshade Compac, Vita) empregando o parâmetro CIELab. As análises foram realizadas imediatamente após a fotoativação e repetidas após 7 dias de armazenamento em água ou em café. Os resultados foram submetidos à análise de variância e ao teste de Tukey (α = 0,05). Resultado Não houve diferença para ΔE nos grupos envelhecidos em água. Quando armazenados em café, o grupo controle apresentou o maior valor de ΔE, enquanto o grupo polido gerou a menor alteração de cor. A aplicação do gel de glicerina produziu resultados intermediários. O parâmetro de translucidez não foi afetado pelos tratamentos testados. Conclusão O uso do gel de glicerina minimiza a alteração de cor nas regiões de difícil acesso aos instrumentos de acabamento e de polimento