Abstract This in vitro study evaluated the biocompatibility and abrasivity of whitening and conventional toothpastes. Samples of conventional (non-whitening) - Edel White Infant (EWI) - and whitening toothpastes - Edel White Whitening (EWW), Edel White CAREFORTE (EWC), Colgate Total 12 Ò Professional (C), and Oral-B Whitening (OB) - were dissolved in culture medium (0.2 g sample weight per mL). Human gingival fibroblasts (hGF) were placed in contact with different dilutions of culture media that had been previously exposed to these toothpastes. Cytotoxicity was then assessed using the methyl tetrazolium test (MTT) and the cell survival rate was determined. Genotoxicity was assessed by the micronucleus test (MNT) and the number of micronuclei was determined before and after exposure to the toothpaste solutions. The enamel surface roughness was evaluated in specimens of bovine teeth (n = 10 per group) before and after 10,000 brushing cycles, using the investigated toothpastes. The results were statistically analyzed using the Mann-Whitney U test and two-way ANOVA (p < 0.05). According to the MTT assay, EWW and OB presented significant cytotoxicity (p < 0.01), but no genotoxic (MNT) effects (p > 0.05). C toothpaste was statistically significantly abrasive to the enamel surface (p < 0.01). The findings of this study may be helpful for individualized selection of commercial toothpastes, as some whitening toothpastes present significant cytotoxicity and conventional toothpaste cause significant surface changes.

ABSTRACT This study evaluated the effect of different artificial aging on fluorescence of resin composites. Forty-five cylindrical specimens (6mm in diameter and 1mm thick) were made of each resin composite: IPS Empress Direct, Filtek™ Z350 XT, and Durafill. A baseline measurement of fluorescence by the direct method using the fluorescence spectrophotometer RF-5301 PC was performed. After, resin specimens were divided into 3 groups according to artificial aging protocol to be submitted: (1) aging by mechanical brushing: 30,000 cycles were performed, with fluorescence measurements after 10,000, 20,000 and 30,000 cycles; (2) chemical aging by ethanol: the samples were immersed in ethanol for 15 days, with measurements after 5, 10 and 15 days of immersion; (3) light aging: resin specimens were subjected to UV radiation for 216h with fluorescence readings after 72, 144, 216h. Data were submitted to one-way repeated measures ANOVA and Tukey’s test (α=0.05). Baseline fluorescence of the tested resins was ranked in this ascending order: Durafill < Filtek Z350 XT < IPS Empress Direct. Simulated toothbrushing and ethanol immersion reduced fluorescence, except for Z350 XT. For light exposition, fluorescence was reduced after 100h for Empress Direct and Durafill, while a reduction after 100h and 200h was detected for Z350 XT. Artificial aging protocols influenced the fluorescence and that this phenomenon is material dependent. In general, the fluorescence is reduced with aging.

Pacientes em tratamento ortodôntico apresentam restaurações provisórias com frequência. No entanto, poucos estudos avaliam a influência dos adesivos na resistência ao cisalhamento dos bráquetes nessas superfícies. A resina acrílica é comumente indicada para colagem de bráquetes, porém o uso do cianoacrilato como adesivo ortodôntico é uma opção analisada. O objetivo do presente trabalho foi avaliar o desempenho do cianoacrilato associado aos materiais comumente utilizados para a fixação de bráquetes metálicos em restaurações provisórias de resina acrílica. Quarenta amostras em resina acrílica foram preparadas e as superfícies homogeinizadas com lixas de carboneto de silício (320 e 600). Em seguida, as amostras foram divididas aleatoriamente em quatro grupos (n=10) com base no tratamento de superfície e agente de união: G1 - bráquetes colados com resina acrílica; G2 - bráquetes colados com resina acrílica e aplicação de cianoacrilato; G3 - bráquetes colados com Transbond(tm) XT; G4 - bráquetes colados com Transbond(tm) XT e aplicação de cianoacrilato. Foram utilizados bráquetes ortodônticos de aço inoxidável, prescrição Roth, Kirium (3M/Abzil) para incisivos centrais superiores direitos, slot 022. Após colagem, as amostras foram submetidas ao teste de cisalhamento a uma velocidade de 0,5mm/min em uma máquina de ensaios universal (EMIC DL-1000). Os dados foram coletados e submetidos à análise estatística pelo teste ANOVA com nível de significância de 5%. A associação de resina acrílica ao cianoacrilato (G2) resultou na maior resistência ao cisalhamento (13,76 MPa), mas não significativa em comparação aos valores obtidos para a resina acrílica (G1= 7,76 MPa). O mesmo pôde ser observado para a associação Transbond(tm) XT e cianoacrilato (G4= 4,03 MPa) em relação a utilização da Transbond(tm) XT de forma isolada (G3= 3,87 MPa) e resina acrílica. O tratamento de superfície tem efeito significativo na resistência da união dos bráquetes colados aos materiais provisórios. A associação de cianoacrilato ao monômero de metilmetacrilato apresentou maior resistência ao cisalhamento, sendo mais indicada clinicamente.

Patients in orthodontic treatments frequently present composite restorations. However, few studies evaluated the influence of bonding materials within braces shearing bond strength on composite surfaces. The acrylic resin became the recommended material for bonding brackets on these surfaces; however the use of cyanoacrylate emerged as a potential option. The present study aimed to evaluate the performance of cyanoacrylate associated with orthodontic materials commonly used for the fixation of metallic braces on temporary restorations of acrylic resin. Forty samples were prepared with acrylic resin and homogenized with silicon carbide sand paper (320 and 600). The samples were randomly divided in four groups (n=10) based on the material treatment and bonding agent: G1 - braces bonded with acrylic resin; G2 - braces bonded with acrylic resin combined with application of cyanoacrylate; G3 - braces bonded with Transbond(tm) XT; G4 - braces bonded with Transbond(tm) XT combined with application of cyanoacrylate. Only stainless steel braces were used, prescription Roth, Kirium (3M/Abzil) designed for maxillary right central incisors, slot 022. After bonding, the sample underwent shearing tests at 0.5mm/min within a standard testing device (EMIC DL-1000). Statistical data consisted of ANOVA with significance level set at 5%. Group 2 (G2) reached major shearing strength (13.76 MPa). However, it was not statistically significant in face of the outcomes of Group 1 (G1) (G1= 7.76 MPa). The same was observed for the association of Transbond(tm) XT and cyanoacrylate (G4= 4.03MPa) compared with isolated Transbond(tm) XT (G3= 3.87 MPa) and acrylic resin. Surface treatment of orthodontic material revealed a significant effect on shearing strength of temporary materials. The association between cyanoacrylate with monomer of methyl methacrylate presented major shearing strength, becoming more indicated for clinical interventions.

ResumoIntroduçãoO cimento resinoso dual é o principal material para cimentação de cerâmicas. Contudo, fatores, como fonte de luz, podem influenciar no desempenho do cimento.ObjetivoAvaliar a influência de duas fontes de luz de diferentes intensidades sobre a microdureza de um cimento resinoso quando fotoativado sob diferentes cerâmicas.Material e métodoForam fotoativados 40 espécimes de cimento resinoso dual (10 mm × 1,0 mm) por meio de duas fontes de luz LED, com intensidades de 1.000 mW/cm² e 800 mW/cm² durante 40 segundos, sob cerâmicas (15 mm × 2 mm) à base de zircônia, espinélio MgAl2O4 e dissilicato de lítio. No grupo controle, foi utilizada uma placa de vidro de mesma dimensão. As amostras tiveram a superfície regularizada com lixa d`água (600 e 1200). Após armazenagem a seco no escuro (24 h), foram realizadas as medidas de microdureza Vickers (HMV Shimadzu - 50g/10 segundos). Os dados foram submetidos à Anova fatorial e ao teste de Tukey com nível de significância de 5%.ResultadoO cimento polimerizado apresentou valor médio de microdureza e desvio padrão para o grupo controle de 43,9±1,5 e 43,4±1,3, para as intensidades de 1.000 mW/cm2 e 800 mW/cm2, respectivamente. O menor valor de microdureza do cimento foi observado para a cerâmica à base de espinélio MgAl2O4, polimerizado a 800 mW/cm², com valor de 34,3±3,3.ConclusãoO tipo de cerâmica e a intensidade da fonte de luz influenciam na microdureza do cimento. A intensidade de 1.000 mW/cm2 sobre as cerâmicas à base de zircônia e espinélio MgAl2O4 resultaram na melhor combinação de valores de dureza do cimento.

AbstractIntroductionThe dual-cure resin cement is the main material for luting of ceramic. However, factors such as light source can influence the performance of the cement.ObjectiveEvaluate the influence of two light sources of different intensities on the microhardness of a resin cement when cured under different ceramics.Material and methodForty samples of dual resin cement were photoactivated by two LED light sources, with light intensity of 1000mW/cm² and 800mW/cm², respectively (40 seconds), under the base ceramic Zirconia, Spinel MgAl2O4 and Lithium Disilicate. In the control group, a glass plate was used. Each samples had the surface grounded (600 and 1200). After dry storage in the dark (24 hours), Vickers microhardness measurements were performed (HMV Shimadzu - 50gf/10 seconds). The data were submitted to factorial ANOVA and Tukey's test with significance level of 5%.ResultThe average hardness and standard deviation in the control group for cement polymerized 1000mW/cm² was 43.9±1.5 and 800mW/cm² the value of 43.4±1.3. The lowest value was for the Ceramic base of spinel MgAl2O4, light cured with 800mW/cm² with a value of 34.3±3.3.ConclusionThe ceramic type and intensity of the light source influence the hardness of the cement. The polymerization 1000mW/cm2 on the ceramic based on zirconia and spinel MgAl2O4 resulted in the best combination of hardness cement.