ABSTRACT OBJECTIVE To assess the changes in stress levels, social behavior, dietary and parafunctional habits, oral hygiene, among other conditions perceived by dental students in Brazil during the Covid-19 pandemic and evaluated the correlations between stress level and other variables. METHODS An online questionnaire was developed and validated. Undergraduates enrolled in private and public dental schools were recruited by convenience sampling. Data were collected on the perceived changes regarding stress levels, financial and social characteristics, dietary habits, oral hygiene, health conditions, and parafunctional habits. Quantitative variables were expressed as absolute and relative frequencies. Wilcoxon test evaluated comparisons between perceived changes, and correlations between changes in stress levels and other variables were analyzed by Spearman correlation (α = 0.05). RESULTS A total of 638 dental students, mean age of 22.95 ± 4.10 years, participated in the study. During the pandemic, the reported stress levels increased while household income decreased (p < 0.05). Late dinners and mindless eating increased in frequency, whereas oral hygiene decreased (p < 0.05). Most of the health conditions and parafunctional habits assessed changed (p < 0.05). Perceived stress levels showed poor negative correlations with household income (rS = −0.14), poor positive correlations with the pressure to contribute financially in the household (rS = 0.19), and poor positive correlations with food choice frequency (rS = 0.15) (p < 0.05). CONCLUSIONS Dental students reported perceived changes in stress levels, dietary habits, oral hygiene, health conditions, parafunctional habits, and social behavior. Moreover, the results showed poor correlations, as students with higher stress levels tended to have the lowest household income, feel pressured to contribute financially in the household, and present a high meal intake frequency. behavior Covid19 Covid 19 Covid-1 validated sampling characteristics frequencies α 0.05. 005 0.05 . 0 05 0.05) 63 2295 22 95 22.9 410 4 10 4.1 years study p rS −0.14, 014 −0.14 , 14 −0.14) 0.19, 019 0.19 0.19) 0.15 015 15 Moreover Covid1 1 Covid- 00 0.0 6 229 2 9 22. 41 4. 01 −0.1 0.1 0. −0. −0 −

ABSTRACT OBJECTIVE To assess the changes in stress levels, social behavior, dietary and parafunctional habits, oral hygiene, among other conditions perceived by dental students in Brazil during the Covid-19 pandemic and evaluated the correlations between stress level and other variables. METHODS An online questionnaire was developed and validated. Undergraduates enrolled in private and public dental schools were recruited by convenience sampling. Data were collected on the perceived changes regarding stress levels, financial and social characteristics, dietary habits, oral hygiene, health conditions, and parafunctional habits. Quantitative variables were expressed as absolute and relative frequencies. Wilcoxon test evaluated comparisons between perceived changes, and correlations between changes in stress levels and other variables were analyzed by Spearman correlation (α = 0.05). RESULTS A total of 638 dental students, mean age of 22.95 ± 4.10 years, participated in the study. During the pandemic, the reported stress levels increased while household income decreased (p < 0.05). Late dinners and mindless eating increased in frequency, whereas oral hygiene decreased (p < 0.05). Most of the health conditions and parafunctional habits assessed changed (p < 0.05). Perceived stress levels showed poor negative correlations with household income (rS = −0.14), poor positive correlations with the pressure to contribute financially in the household (rS = 0.19), and poor positive correlations with food choice frequency (rS = 0.15) (p < 0.05). CONCLUSIONS Dental students reported perceived changes in stress levels, dietary habits, oral hygiene, health conditions, parafunctional habits, and social behavior. Moreover, the results showed poor correlations, as students with higher stress levels tended to have the lowest household income, feel pressured to contribute financially in the household, and present a high meal intake frequency.

Abstract This study evaluated the influence of non-thermal argon plasma applied to dentin on the shear strength of two adhesive systems. Ninety tooth fragments were embedded in epoxy resin and distributed into experimental groups (n=15): G1 and G4 - adhesive systems applied according to the manufacturers’ instructions; G2 and G5 - dentin treated with non-thermal argon plasma for 30 seconds before hybridization; G3 and G6 - dentin treated with non-thermal argon plasma for 30 seconds after hybridization. Cylinders were made with composite resin in the adhesive area, and the specimens were submitted to the shear strength test. Higher values were observed when applying the plasma treatment after hybridization (G1: 26.51 MPa, G2: 29.22 MPa, G3: 30.27 MPa, G4: 22.66 MPa, G5: 28.33 MPa, G6: 29.32 MPa). The treatment with non-thermal argon plasma significantly increased the shear strength values regardless of the application time.

Resumo Introdução Com o aumento da procura por procedimentos estéticos, dúvidas surgem quanto à manutenção e regressão de cor, especialmente, no que tange a necessidade de restrição quanto à alimentos escuros durante o procedimento clareador ou a sua influência quanto à estabilidade e eficácia do tratamento. Objetivo Avaliar a influência de agentes pigmentantes sobre o esmalte dental durante o tratamento clareador imediato com peróxido de hidrogênio a 35%. Material e método 60 dentes bovinos foram divididos em 6 grupos (G) (n=10): G1: água destilada (controle), G2: café, G3: refrigerante à base de cola, G4: vinho, G5: chá-mate, e G6: açaí industrializado. As amostras foram submetidas ao clareamento imediato utilizando peróxido de hidrogênio a 35% durante 21 dias (3 aplicações de 15 minutos por sessão a cada 7 dias) e submetidas à imersão dos pigmentos entre cada sessão durante 15 minutos. A avaliação da cor foi realizada antes do inicio do clareamento e após 21 dias, mediante o uso do espectrofotômetro. Os dados obtidos foram submetidos ao ANOVA one-way e análise de heterocedasticidade pelos testes de Welch e Brown-Forsythe. O teste de Tamhane foi utilizado para a comparação entre os grupos. Resultado Houve alteração de cor visível ao olho nu, uma vez que a média de ΔE em todos os grupos testados foi maior que 3,7. Contudo, não houve diferença estatística entre o grupo controle em relação aos grupos avaliados. Conclusão O contato de agentes pigmentantes no esmalte dental bovino não influenciou o resultado final do clareamento dental imediato.

Abstract Introduction Considering the increased search for esthetic procedures, questions emerge about the maintenance and regression of color, especially regarding the need to restrict dark foods during bleaching procedures or their influence on the stability and effectiveness of the treatment. Objective To assess the influence of staining agents on tooth enamel during immediate bleaching treatment with 35% hydrogen peroxide. Material and method Sixty bovine teeth were divided into six groups (G) (n=10): G1: distilled water (control); G2: coffee; G3: cola soft drink; G4: wine; G5: mate tea; and G6: industrialized açaí. The samples were subjected to immediate bleaching using 35% hydrogen peroxide for 21 days (three applications of 15 minutes per session, every seven days) and pigment immersion between each session for 15 minutes. The color was assessed before starting bleaching and after 21 days, using a spectrophotometer. The data obtained were subjected to one-way ANOVA and heteroscedasticity analysis by the Welch and Brown-Forsythe tests. The Tamhane test was used for group comparison. Result The color change was visible to the naked eye, considering the mean ΔE in all groups tested was higher than 3.7. However, there was no statistical difference between the control group and the groups assessed. Conclusion The contact of staining agents on bovine tooth enamel did not affect the final result of the immediate tooth bleaching.

Resumo Introdução A obtenção do resultado esperado durante o clareamento dental exige um diagnóstico correto do tipo de coloração apresentado. As causas da coloração dos dentes diferem dependendo do fator etiológico. Objetivo Avaliar a mudança de cor causada pela imersão dos dentes bovinos na solução de café durante o clareamento dentário caseiro, utilizando gel de peróxido de carbamida a 16%. Material e método Trinta e três dentes bovinos hígidos foram distribuídos em três grupos de onze dentes cada: 1 - Dentes clareados quatro horas por dia durante 21 dias; 2 – Dentes clareados quatro horas por dia durante 21 dias e imerso em solução de café imediatamente após o clareamento dentário; 3 – Dentes clareados quatro horas por dia durante 21 dias e imerso em solução de café quatro horas após o término do clareamento dentário. Imersão em café foi realizada durante 15 minutos e a cor dos dentes foi avaliada antes do início do procedimento do clareamento e após 21 dias com um espectrofotômetro intraoral. O teste Shapiro-Wilk foi utilizado para avaliar a homocedasticidade e os dados foram submetidos à análise de variância de um fator (ANOVA) e ao teste de Tukey (p <0,05). Resultado A mudança de cor observada no grupo 1 (5,76 ± 2,74)A não foi estatisticamente diferente do grupo 2 (8,83 ± 5,11)A, imerso em solução de café imediatamente após o clareamento dentário, e do grupo 3, imerso em café quatro horas após o clareamento dental (8,20 ± 3,71). Conclusão O café não interferiu nos resultados do clareamento dental, independentemente do tempo após o procedimento. Portanto, restrições alimentares não são necessárias durante o clareamento dental.

Abstract Introduction Obtaining the result expected during tooth bleaching requires a correct diagnosis of the type of staining presented. The causes of tooth staining differ depending on the etiological factor. Objective To assess the color change caused by the immersion of bovine teeth in coffee solution during at-home tooth bleaching using a 16% carbamide peroxide gel. Material and method Thirty-three sound bovine teeth were assigned to three groups of eleven teeth each: 1 – Teeth bleached (TB) four hours per day for 21 days; 2 – TB four hours per day for 21 days and immersed in coffee solution immediately after tooth bleaching; 3 – TB four hours per day for 21 days and immersed in coffee solution four hours after the end of tooth bleaching. Immersed in coffee was performed for 15 minutes and tooth color was assessed before the start of the bleaching procedure and after 21 days with an intraoral spectrophotometer. Test Shapiro-Wilk was used to assess homoscedasticity and data were submitted to one-factor Analysis of Variance (ANOVA) and Tukey’s test (p <0.05). Result The color change observed in group 1 (5.76 ± 2.74)A was not statistically different from group 2 (8.83 ±5.11)A, which was immersed in coffee solution immediately after tooth bleaching, and from group 3, which was immersed in coffee solution four hours after tooth bleaching (8.20 ±3.71)A. Conclusion Coffee did not interfere with the tooth bleaching results, regardless of the time after the procedure. Hence, diet restrictions are not necessary during tooth bleaching.

Resumo Introdução Os pinos de fibra de vidro são uma alternativa aos núcleos metálicos e apresentam vantagens, tais como: estética, módulo de elasticidade semelhante à dentina e cimentação imediata após o término do tratamento endodôntico. Ainda, apresentam a capacidade de aderir ao cimento resinoso e este, à dentina, por meio de técnicas adesivas. Objetivo Comparar a adesão de um cimento resinoso convencional e um autoadesivo a pinos de fibra de vidro, e os efeitos de diferentes tratamentos de superfície na resistência adesiva dos pinos. Material e método Trinta pinos foram divididos em três grupos: Controle: sem tratamento na superfície; Jateamento: jateamento com óxido de alumínio por 30 segundos, e Peróxido: imersão em peróxido de hidrogênio 24% por um minuto. Em seguida, corpos de prova foram obtidos a partir de cilindros de cimento resinoso contendo o pino de fibra posicionado no centro de seu longo eixo. Em cada grupo, cinco pinos foram associados ao adesivo Âmbar + cimento convencional AllCem Core e os outros cinco pinos, ao cimento autoadesivo RelyX U200. O conjunto pino/cimento foi segmentado e avaliado em relação à resistência de união (RU) por push-out. Os dados foram analisados estatisticamente pelos testes de ANOVA e Tukey (p<0,05). Resultado Os cimentos avaliados exibiram valores de RU semelhantes. Em relação aos tratamentos de superfície, os maiores valores de RU foram encontrados no grupo Jateamento. Conclusão O cimento convencional, AllCem Core, e o cimento autoadesivo, RelyX U200, mostraram valores de resistência de união semelhantes. Ainda, o jateamento com óxido de alumínio favoreceu a adesão dos pinos aos cimentos.

Abstract Introduction The fiberglass posts are an alternative to the metal cast, presenting some advantages, such as aesthetics, tensile modulus similar to dentin and can be placed in a single session, immediately after the endodontic treatment. It also has the ability to adhere to the resin cement and the last to dentin by means of bonding techniques. Objective To compare the adhesion of a conventional resin cement with a self-adhesive to fiberglass posts, and the effects of different surface treatments on adhesion of posts. Material and method Thirty fiber posts were divided into 3 groups: control: untreated surface; Blasting: blasting with aluminum oxide for 30 seconds and peroxide: immersion in 24% hydrogen peroxide for 1 minute. Then, the samples were obtained from resin cement cylinders containing the fiber post positioned in the center of its long axis. In each group 5 posts were associated with the adhesive Ambar+conventional cement Allcem Core and the other 5 posts with the self-adhesive cement RelyX U200. The post/cement sample was segment in discs and evaluated for bond strength (BS) by push-out test. Data were analyzed statistically by ANOVA and Tukey tests (p<0.05). Result The cements evaluated exhibited similar BS values. Regarding surface treatments, the highest BS values were found in blasting group. Conclusion Conventional cement, Allcem Core, and self-adhesive, RelyX U200, showed similar bond strength values. Also, blasting with aluminum oxide favored the adhesion of posts to cements.

The aim of this study was to determine the degradation resistance of three new formulations-silorane-, Ormocer- and dimer-acid-based materials-and compare them to the traditional dimethacrylate-based materials. One silorane- (Filtek P90, P90), one Ormocer- (Ceram-X, CX), one dimer-acid- (N'Durance, ND) and two dimethacrylate-based (Filtek P60, P60; Tetric Ceram, TC) materials were investigated. Water sorption (Wsp) and solubility (Wsl) were determined after the materials were immersed in water for 28 days. Knoop hardness (KH) was determined before and after 24 h immersion in pure ethanol. The flexural-strength (FS) was determined by the bending test after one-week storage in a dry environment or after one-week immersion in pure ethanol. Data were submitted to analysis of variance (ANOVA) and Tukey's test (95%). The three new formulations showed lower Wsp than the dimethacrylate-based formulation. CX (0.50 ± 0.17%) and ND (0.72 ± 0.19%) exhibited the lowest Wsp, whereas P90 (0.02 ± 0.03%) and P60 (0.04 ± 0.03%) showed the lowest Wsl. All resins showed reduced Knoop hardness number (KHN) after ethanol immersion. P60 presented the lowest decrease in KH value (19 ± 5%). TC (48 ± 3%) and P90 (39 ± 9%) showed the highest KHN decrease after ethanol storage. The FS of CX, ND and TC were affected by ethanol storage. The new formulations did not improve the degradation resistance, as compared with the traditional methacrylate-based materials.

The purpose of this study was to evaluate the fracture strength of roots that were prosthetically restored with metallic posts with or without any remaining coronal structure and with different finish lines. Sixty bovine incisors were sectioned below the cementoenamel junction, endodontically treated, and randomly divided into six experimental groups (n = 10) containing teeth with or without any remaining coronal structure, and with a beveled shoulder, a bevel, or a shoulder finish line design. The metallic posts were luted with dual-cured resin cement. The cores were made with composite resin, and metal crowns were cemented with zinc phosphate cement. The specimens were subjected to a tangential compressive load (135º angle) at a crosshead speed of 0.5 mm/min until failure, using a universal testing machine. The fracture strength data were analyzed using the ANOVA and LSMeans (least square means) tests (α= 0.05). The data indicated that the teeth with 2 mm of remaining coronal structure showed the highest fracture strength values when compared with the teeth without any remaining structure (p < 0.05). As to the different finish line designs, the highest fracture strength values were obtained for the beveled shoulder, followed by the bevel and then by the shoulder designs (p < 0.05). It may be concluded that, to increase fracture strength, a beveled shoulder and 2 mm of remaining coronal structure are the ideal conditions.