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Abstract Objective: To compare the clinical effect of two desensitizing agents used before the application of a bleaching gel based on 35% hydrogen peroxide (HP). Material and Methods: 30 patients were selected, and two desensitizing agents with different mechanisms of action were applied: Fluorine Neutral 2% (FN), which acts by blocking dentinal canaliculi while Potassium Nitrate 5% with 2% Sodium Fluoride (PN/SF) that acts in nerve transmission and blockade. Desensitizers were used before the application of 35% HP. For whitening, three clinical sessions were performed, with an interval of seven days, with three applications of the bleaching gel for 15 minutes, totaling 45 minutes/session. Tooth sensitivity (TS) was assessed with the numerical analog scale, and a spectrophotometer was used to obtain the color variation (ΔE). ΔE were submitted to ANOVA and Tukey test (p<0.05), and TS data were submitted to a two-way ANOVA analysis. Results: For sensitivity experience, the Tukey test indicated differences between PN/SF and the placebo I, but there was no statistically significant difference between FN and the placebo II. The TS was lower when the desensitizing gel was used during the bleaching procedure compared to after treatment, regardless of the desensitizing agents. Conclusion: PN/SF before in-office tooth bleaching can reduce TS intensity, and the use of desensitizing gel before bleaching did not affect the bleaching efficacy.

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Aim This study aims to evaluate and validate the sensibility and the level of agreement between different gingival color measures obtained by a spectrophotometer (SPECTRO) and a photography (PHOTO) method. Methods Among 40 patients, the color was measured 2 mm apical to the gingival margin by CIE L*, a*, b* system using a reflectance spectrophotometer and the photography's plus software. The level of agreement between three different measures (m1, m2, m3) in parameters L*, a*, b*, and ∆E (color variation) was evaluated by random and systematic errors, as well as the limits and coefficient of concordance. A comparison between the methods was performed by the Bland-Altman test and the sensibility level was evaluated accordingly to the ∆E: 3.7 thresholds with p<0.05 as the level of significance for these comparisons. Results The SPECTRO method has not presented the systematic error (p>0.05) and had reproducibly and agreement level in three variable measures L* (r: 0.6), a* (r: 0.3), and b* (r: 0.5) as to the PHOTO method L* (r: 0.6), a* (r: 0.5), and b* (r: 0.5), which presented systematic error in L* values (p<0.05). The means of ∆E between measurements were: 6.5 SPECTRO and 5.9 PHOTO. There was no good level of sensitivity ∆E> 3.7 and agreement between the methods, mainly for the a* values. On the other hand, for the L* and in for the most comparisons of b* values, the level of agreement was higher. Conclusion Both methods could quantify the gingival color from the coordinates L *, a *, and b *, which has shown greater reliability between the measurements acquired by the SPECTRO method.

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O objetivo deste trabalho foi analisar e correlacionar os resultados de qualidade do leite cru refrigerado de dez propriedades rurais de Viçosa (MG) obtidos por métodos de referências do Ministério da Agricultura, Pecuária e Abastecimento e por espectrofotômetros de luz infravermelha em três laboratórios (A, B e C) credenciados pelo mesmo órgão de fiscalização. As amostras de leite foram analisadas quanto à contagem bacteriana, contagem de células somáticas (CCS) e teores de gordura, proteína e extrato seco desengordurado (ESD). Não houve discordância de amostras de leite quanto aos teores de proteína e gordura. Porcentagens diferentes de discordância foram observadas entre os resultados dos laboratórios e método de referência quanto à CCS, contagem bacteriana e teores de ESD. Os teores médios de proteína dos laboratórios A e B e os teores médios de ESD de todos laboratórios não foram estatisticamente iguais (p<0,05) aos teores obtidos pelo método de referência. Os teores de gordura obtidos no laboratório B não tiveram correlação estatística (p>0,05) com os teores obtidos pelo método de referência. Observou-se que as CCS e contagens bacterianas médias de todos os laboratórios foram estatisticamente iguais (p>0,05) e correlacionadas (p<0,05) às contagens médias obtidas pelos métodos de referência. Conclui-se que os teores de proteína em dois laboratórios e ESD em todos os laboratórios não são equivalentes com os métodos de referência do MAPA. É importante que os laboratórios revejam a calibração dos seus equipamentos quanto à quantificação dos teores de sólidos do leite.

The objective of this study was to analyze and to correlate the results of refrigerated raw milk quality in ten farms of Viçosa (MG). The milk was analyzed by the Ministério da Agricultura, Pecuária e Abastecimento standard methods and by infrared spectrophotometers in three laboratories (A, B and C) accredited by the same institution. The milk samples were analyzed for bacterial counts, somatic cell count (SCC) and fat, protein and solids not fat (SNF) tenors. There were no disagreement milk samples as the protein and fat tenors. Different percentages of disagreement were observed between the results of laboratory and standard method as the SCC, bacterial count and SNF tenor. The protein mean tenor of A and B laboratories and the SNF mean tenor of all laboratories were not statistically equal (p<0.05) the tenors obtained by standard method. The fat tenors obtained in B laboratory were not statistically correlated (p>0.05) with tenors obtained by the standard method. It was observed that the means of SCC and bacterial counts of all laboratories were statistically the same (p>0.05) and correlated (p<0.05) to the means counts obtained by standard methods. It is concluded that the protein tenors in two laboratories and SNF in all laboratories are not equivalent with the reference methods of MAPA. It is important that laboratories review the calibration of the equipment on the quantification of milk solids tenors.

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Introducción: Las diferencias en las propiedades mecánicas de los materiales cerámicos y a base de resina plantean la interrogante sobre cuál puede tener un mejor desempeño a largo plazo. Objetivos: Evaluar la resistencia flexural y estabilidad de color de diferentes materiales restauradores estéticos indirectos. Métodos: Los materiales seleccionados fueron Filtek™ Z250 XT (3M ESPE), Ceramage (SHOFU Dental), VITA VM® LC y VITA ENAMIC® (VITA Zahnfabrik), IPS e.max® (Ivoclar-Vivadent) y Zolid FX (Amann Girrbach AG). El ensayo de resistencia flexural (n = 10) fue realizado en una máquina universal de ensayos mecánicos. Las lecturas de color (n = 5) se midieron en un espectrofotómetro VITA Easyshade V®. Resultados: Los materiales totalmente cerámicos mostraron un mejor desempeño mecánico (p < 0,001). Los resultados de estabilidad de color muestran que Ceramage, IPS e.max® y Zolid FX, mostraron una diferencia estadísticamente significativa (p ≤ 0,002) con Filtek Z250 XT, VITA VM® LC y VITA ENAMIC®. Conclusiones: Los materiales totalmente cerámicos presentaron una mayor resistencia flexural y estabilidad de color que los materiales de base polimérica. A pesar de ello, los materiales estéticos indirectos con polímeros en su composición, como Ceramage, se presentan como una alternativa válida, ya que además de tener propiedades mecánicas adecuadas, poseen una estabilidad de color semejante a los materiales cerámicos(AU)

Introduction: Differences in the mechanical properties of ceramic and resin-based materials pose the question of which of the two will perform better in the long run. Objectives: Evaluate the flexural resistance and color stability of different indirect esthetic restorative materials. Methods: The materials selected were Filtek™ Z250 XT (3M ESPE), Ceramage (SHOFU Dental), VITA VM® LC and VITA ENAMIC® (VITA Zahnfabrik), IPS e.max® (Ivoclar-Vivadent) and Zolid FX (Amann Girrbach AG). The flexural resistance assay (n = 10) was conducted in a universal mechanical testing machine. Color readings (n = 5) were taken with a VITA Easyshade V® spectrophotometer. Results: All-ceramic materials had better mechanical performance (p < 0.001). Color stability results show that Ceramage, IPS e.max® and Zolid FX displayed a statistically significant difference (p ≤ 0.002) with respect to Filtek Z250 XT, VITA VM® LC and VITA ENAMIC®. Conclusions: All-ceramic materials exhibited greater flexural resistance and color stability than polymer-based materials. However, indirect esthetic materials with polymers in their composition, such as Ceramage, are presented as a valid alternative, due to their appropriate mechanical properties and their color stability, which is similar to that of ceramic materials(AU)

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Abstract Objective: To compare the cytotoxicity level of a new calcium silicate-based resin cement (TheraCem) with two commonly used cements, including a conventional self-adhesive resin cement (Panavia SA) and a resinmodified glass ionomer cement (FujiCem2), on the human gingival fibroblast cells after 24 and 48 hours. Material and Methods: Twelve discs of each cement type were fabricated. The extract of cement disks was made by incubating them in the cell medium. Human gingival fibroblast cells were cultured and exposed to cement extracts for 24 h and 48 h. MTT assay was performed on extracts and optical density and cell viability rates were calculated by the spectrophotometer device at 570 nm. Data were analyzed using ANOVA and Tukey HSD tests. Results: The cell viability rates after 24 hours and 48 hours were as follows: TheraCem: 89.24% and 85.46%, Panavia SA: 49.51% and 46.57% and FujiCem2: 50.63% and 47.36%. TheraCem represented the highest cell viability rate. However, no significant difference was noted between Panavia SA and FujiCem2. Time had no significant effect on cell viability. Conclusion: TheraCem exhibited the best results among three tested cements and was considered non-toxic. Panavia SA and FujiCem2 were not significantly different regarding the cell viability rate. Time had no significant effect on the cytotoxicity level of cements (AU).

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Abstract Objective: To analyze the self-reported need of patients compared to professional indications for tooth whitening. Material and Methods: Initially, 58 undergraduate students responded to a form that highlighted the question: "Do you think you need to have your teeth whitened?" Among those who answered positively to the previous question, ten individuals were photographed with their smiles. In addition, they were asked to point out, on the Vita 3D-Master scale, which color they believed their teeth had, a value that was compared to the actual color obtained by a spectrophotometer. Finally, the photographs were presented to dentists, who were asked about the indication or not of the whitening treatment. Results: Most interviewees (63.8%) self-reported the need for whitening, as well as there was a greater incidence of a positive indication among professionals (53.9%). Pearson's Chi-square test revealed a relationship between patient gender and the training course on the desire to have teeth whitened. Among the professionals, the specialty, as well as time since graduation, interfered in the indication for whitening. Conclusion: Professionals and patients share the aesthetic ideal directly related to light teeth; most patients self-perceive the color of their teeth darker than it actually is; the opinion about the color of the teeth has an extremely subjective character and varies greatly from one professional to another (AU).

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Objetivo: O objetivo deste estudo é avaliar o efeito de múltiplas queimas e envelhecimento na cor e na translucidez da vitrocerâmica de dissilicato de lítio reprensada (IPS e.max press). Material e Métodos: Um total de 42 discos de dissilicato de lítio (15 mm x 1 mm) foram fabricados usando a técnica de prensa térmica seguindo as instruções dos fabricantes. Eles foram divididos em três grupos de acordo com o número de ciclos de prensagem (n=14): Grupo P1 (pressionado uma vez), Grupo P2 (pressionado duas vezes) e Grupo P3 (pressionado três vezes). Cada grupo foi subdividido em dois subgrupos de acordo com o número de ciclos de queima (n=7): Subgrupo (F2): 2 ciclos de queima, Subgrupo (F4): 4 ciclos de queima. Em seguida, todos os corpos de prova foram submetidos à termociclagem. Os parâmetros de cor e translucidez (TP) foram avaliados por espectrofotômetro; após a prensagem, queima (ΔE1: diferença de cor entre prensagem e queima) e envelhecimento (ΔE2: diferença de cor entre prensagem e envelhecimento). Resultados:ΔE1 para o subgrupo F2 (3,38) apresentou menor valor estatisticamente significante do que ΔE1 para o subgrupo F4 (3,94). Após o envelhecimento, o grupo P3 apresentou o maior ΔE2 estatisticamente significante (6,41). Um ΔE2 estatisticamente inferior foi encontrado no grupo P2 (5,55). O grupo P1 apresentou o menor ΔE2 estatisticamente significante (4,28). O TP para o subgrupo F2 (18,27) apresentou valor superior ao subgrupo F4 (17,78). Houve uma diminuição estatisticamente significante no TP após o envelhecimento para todos os grupos testados. Conclusão: O aumento do número de ciclos de queima e de envelhecimento afetaram a cor e a translucidez do dissilicato de lítio reprensado. (AU)

Objective: The aim of this study is to evaluate the effect of multiple firings and aging on color and translucency of repressed lithium disilicate glass ceramic (IPS e.max press). Material and Methods: A total of 42 lithium disilicate discs (15 mm x 1 mm) were fabricated using heat press technique following the manufacturers' instructions. They were divided into three groups according to the number of pressing cycles (n=14): Group P1 (pressed once), Group P2 (pressed twice) and Group P3 (pressed thrice). Each group was subdivided into two subgroups according to the number of firing cycles (n=7): Subgroup (F2): 2 firing cycles, Subgroup (F4): 4 firing cycles. Then all specimens were subjected to thermocycling. Color and translucency parameter (TP) were evaluated by spectrophotometer; after pressing, firing (ΔE1: color difference between pressing and firing) and aging (ΔE2: color difference between pressing and aging). Results:ΔE1 for subgroup F2 (3.38) showed statistically significant lower value than ΔE1 for subgroup F4 (3.94). After aging, group P3 showed the statistically significant highest ΔE2 (6.41). A statistically significant lower ΔE2 was found with group P2 (5.55). Group P1 showed the statistically significant lowest ΔE2 (4.28). TP for subgroup F2 (18.27) showed higher value than subgroup F4 (17.78). There was a statistically significant decrease in TP after aging for all tested groups. Conclusion: Increasing the number of firing cycles and aging affected color and translucency of repressed lithium disilicate. (AU)

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Objective: To determine the effect of the restorative technique, material's opacity and the selected light sources on the curing potential (CP) in deep cavities. Material and Methods: The radiant exitance (mW/cm2) of two light curing units (Bluephase G2 and Radii-Cal) was determined at 0 and 8 mm distance from a power meter sensor (Ophir). Two bulk-fill composites of regular consistency (Opus, FGM; and Filtek One, 3M) and a conventional one (Sirius-Z, DFL) were considered and the level of their opacity were determined by a sphere-based spectrophotometer (SP60, X-Rite). The degree of C=C conversion (DC) was determined by spectroscopy (FTIR-ATR) at 0.05 and 8 mm depths and the CP considered the ratio between them. The "incremental technique" considered 4 increments of 2mm thickness each, whereas the "bulk-fill technique considered 2 increments of 4mm-thickness. Data were submitted to analysis of variance and Tukey's test (95%). Pearson's correlation tests were performed to calculate the possible relation between curing potential and materials' opacity. Results: With the incremental technique it was possible to achieve high CP regardless of the light source. The CP of bulk-fill composites was dependent on the light source, whereas Radii-Cal compromised the DC at 8 mm for both materials. The correlation between opacity and CP was dependent on the light source (r = 0.891707246 for Radii-Cal; r = 0.515703768 for Bluephase G2). Conclusion: The bulk-fill technique was dependent on the light source while the incremental was not. The influence of materials' opacity was dependent on the light curing unit.(AU)

Objetivo: Determinar o efeito da técnica restauradora, a opacidade do material e as fontes de luz selecionadas sobre o potencial de cura (PC) em cavidades profundas. Materiais e métodos: A saída radiante (mW/cm2) de duas unidades de cura por luz (Bluephase G2 e Radii-Cal) foi determinada a 0 e 8 mm de distância de um sensor de potência (Ophir). Dois compósistos bulkfill de consistência regular (Opus, FGM; e Filtek One, 3M) e um convencional (Sirius-Z, DFL) foram considerados e o nível de sua opacidade foi determinado por um espectrofotômetro (SP60, X-Rite). O grau de conversão C=C (DC) foi determinado por espectroscopia (FTIR-ATR) a 0,05 e 8 mm de profundidade e o PC considerou a relação entre eles. A técnica incremental considerou 4 incrementos de 2 mm de espessura cada, enquanto que a técnica bulkfill considerou 2 incrementos de 4 mm de espessura. Os dados foram submetidos à análise de variância e ao teste de Tukey (95%). Os testes de correlação de Pearson foram realizados para calcular a possível relação entre o potencial de cura e a opacidade dos materiais. Resultados: Com a técnica incremental foi possível obter um PC elevado, independentemente da fonte de luz. O PC de compósitos bulkfill foi dependente da fonte de luz, enquanto que Radii-Cal comprometeu o DC em 8 mm para ambos os materiais. A correlação entre opacidade e PC foi dependente da fonte de luz (r = 0,891707246 para Radii-Cal; r = 0,515703768 para Bluephase G2). Conclusão: O potencial de polimerização para a técnica bulkfill foi dependente da fonte de luz, enquanto para a técnica incremental não. A influência da opacidade dos materiais sobre a capacidade de polimerização foi dependente da unidade de fotoativação. (AU)

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ABSTRACT: Introduction. One of the most frequently used color analysis system is the Vita 3D Master toothguide. No study has evaluated if there are color differences between the same Vita 3D Master shades obtained from natural teeth, which could determine changes in the color selection. Objective. To determine ΔEab in natural teeth within the corresponding shade given by a spectrophotometer and compare our results with the AT and PT thresholds reported in the literature. Materials and Methods. We obtained 3818 tooth shade data L*a*b from 200 patients in an ambulatory setting. All color differences (ΔEab) between the same Vita 3D Master shades were registered. Mean, range and standard deviation values were determined. Results. We found a wide dispersion of the ΔEab values within each Vita 3D Master shade. When comparing our results with the PT and AT values available in the literature we found a wide dispersion of the ΔEab values, discordant in up to 53% of the cases. Conclusions. We suggest a revision of the available thresholds. Further research is warranted in this field to improve our understanding of color selection and matching. Clinical significance: The available thresholds for assessing color differences in dentistry probably need to be reviewed.

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Objective: To compare the color stability and translucency of aged and unaged experimental zirconia reinforced rice husk nanohybrid composite resin (Zr-Hybrid) with a commercialized nanofilled and a microhybrid composite resin after immersion in four different infusion media. Material and Methods: Three groups of standardized disc-shaped composite resin with 80 samples per group were prepared as follow: Group 1 (Filtek-Z350-XT), Group 2 (Zmack-Comp), and Group 3 (Zr-Hybrid). Each group was further subdivided into aged (n=40) and unaged (n=40) groups. Initial color measurements were taken using a digital spectrophotometer based on CIE L*a*b* color system. Samples in aged subgroup were subjected to 2500 thermal cycles. Subsequently, all samples were immersed in four different types of infusion media (n=10): T1 - Distilled water, T2 - Soft drink, T3 - Tea and T4 - Coffee. After 15 days, color measurements of all samples were measured again. Data were analyzed using two-way ANOVA followed by Bonferroni and paired sample t-tests with a significance level set at P=0.05. Results: Unaged Zr-Hybrid showed comparable color change to Zmack-Comp and Filtek-Z350-XT (P=0.181), but aged Zr-Hybrid demonstrated the lowest color change (P<0.001). Zr-Hybrid exhibited the lowest translucency value (P<0.001), but no significant color and translucency changes (P=0.051 and P=0.069, respectively) were observed between unaged and aged Zr-Hybrid. Soft drink had the greatest effect (P<0.001) on color change, while coffee showed the greatest effect (P<0.001) on translucency. Conclusion: Although Zr-Hybrid showed greater opacity, it still retained its color stability and translucency after accelerated aging compared to commercialized microhybrid and nanofilled composite resins. All infusion media caused discoloration and affected the composite resins' translucency. (AU)

Objetivo: Comparar a estabilidade de cor e translucidez de uma resina composta nanohíbrida de casca de arroz reforçada com zircônia experimental envelhecida e não envelhecida (Zr-Hybrid) com uma resina composta comercial nanoparticulada e microhíbrida após a imersão em quatro meios de infusão diferentes. Material e Métodos: Três grupos de resina composta em forma de disco padronizado com 80 amostras por grupo foram preparados da seguinte forma: Grupo 1 (Filtek-Z350-XT), Grupo 2 (Zmack-Comp) e Grupo 3 (Zr-Hybrid). Cada grupo foi subdividido em grupos de envelhecimento (n = 40) e não envelhecimento (n = 40). As medições iniciais de cor foram feitas usando um espectrofotômetro digital baseado no sistema de cores CIE L * a * b *. As amostras do subgrupo envelhecido foram submetidas a 2500 ciclos térmicos. Posteriormente, todas as amostras foram imersas em quatro tipos diferentes de meios de infusão (n = 10): T1 - Água destilada, T2 - Refrigerante,T3 - Chá e T4 - Café. Após 15 dias, as medições de cor de todas as amostras foram medidas novamente. Os dados foram analisados usando ANOVA dois fatores seguido por Bonferroni e testes t pareados com nível de significância estabelecido em P = 0,05. Resultados: O grupo Zr-Hybrid não envelhecido mostrou uma mudança de cor comparável a Zmack-Comp e Filtek-Z350-XT (P = 0,181), mas o grupo Zr-Hybrid envelhecido demonstrou a menor mudança de cor (P <0,001). Zr-Hybrid exibiu o menor valor de translucidez (P <0,001), mas nenhuma mudança significativa de cor e translucidez (P = 0,051 e P = 0,069, respectivamente) foram observadas entre Zr-Hybrid não envelhecido e envelhecido. O refrigerante teve o maior efeito (P <0,001) na mudança de cor, enquanto o café apresentou o maior efeito (P <0,001) na translucidez. Conclusão: Apesar do grupo Zr-Hybrid tenha mostrado maior opacidade, ele ainda manteve sua estabilidade de cor e translucidez após envelhecimento acelerado em comparação com resinas compostas micro-híbridas e nanoparticuladas comercializadas. Todos os meios de infusão causaram descoloração e afetaram a translucidez das resinas compostas (AU)

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