QUALIDADE FISIOLÓGICA DE SEMENTES DE Tabernaemontana fuchsiaefolia A. DC EM FUNÇÃO DO TESTE DE ENVELHECIMENTO ACELERADO1

Tabernaemontana fuchsiaefolia A. DC é uma espécie da família Apocynaceae, nativa do Brasil, com característica invasora, possuindo potencial para uso em recuperação de áreas degradadas. O trabalho teve o objetivo de avaliar a influência dos métodos de envelhecimento acelerado sobre a qualidade fisiológica e germinação de sementes, utilizando-se o método tradicional e em solução de NaCl, empregando-se a metodologia de gerbox, formando minicâmaras de envelhecimento, em três temperaturas (41, 43 e 45°C) e cinco tempos de envelhecimento (0, 24, 48, 72 e 96 horas). As sementes, após o envelhecimento, foram colocadas para germinar em rolos de papel germitest, em quatro repetições de 25 sementes, em câmaras BOD a temperatura de 30°C, com fotoperíodo de 8 horas. O efeito da temperatura foi comparado pelo teste de Tukey em nível de 5% de probabilidade e o efeito do tempo de envelhecimento, pela análise de regressão. Após 35 dias, foram avaliados percentual, índice de velocidade, tempo médio e frequência da germinação, bem como comprimento de raiz e parte aérea, massa seca de plântulas e percentual de plântulas normais. Observou-se que o método alternativo de envelhecimento com solução de NaCl teve pouca influência na qualidade das sementes, não sendo indicado para testes de vigor para a espécie. O método tradicional, na temperatura de 45°C em período de envelhecimento de 96 horas, promoveu queda na germinação e pode ser utilizado para testar o vigor de sementes de leiteira.

Color stability and surface roughness of artificial teeth brushed with an experimental Ricinus communis toothpaste

Aim: To evaluate, in vitro, the effect of brushing with a Ricinus communis -based experimental toothpaste on color stability and surface roughness of artificial teeth. Methods: Ninety artificial teeth (maxillary central incisors) in different shades, light and dark (NatusDent Triple Pressing, Dentbras) were used. Initial color (Spectrophotometer Easyshade, VITA) and surface roughness (Rugosimeter Surfcorder SE 1700, Kosakalab) readouts were performed. After baseline measurements, samples were assigned to 10 groups (n=9) according to the artificial tooth shade and type of toothpaste used during the mechanical brushing test (Pepsodent, MAVTEC): Sorriso Dentes Brancos – SDB, Colgate Luminous White - CLW (Colgate-Palmolive), Close up White Now - CWN (Unilever), Trihydral - THL (Perland Pharmacos) and Ricinus communis - RCE (Experimental). After 29,200 cycles of brushing, corresponding to 2 years of brushing by a healthy individual, new color and roughness readouts of the specimens were performed. Data (before and after the tests) were statistically analyzed (2-way repeated measures ANOVA, Tukey, p<0.05). Results: RCE toothpaste produced the greatest color stability for dark tooth shade and the second best color stability for light tooth shade. For surface roughness alteration, there was no difference (p>0.05) for any tested toothpaste regardless of tooth shade. Conclusions: The experimental Ricinus communis toothpaste did not cause color and surface roughness alteration in the artificial teeth, and it may be considered a suitable option for denture cleaning.

Influence of shade, curing mode, and aging on the color stability of resin cements

The color stability of resin cements is essential for aesthetic restorations. Aim: To evaluate the influence of shade and aging time on the color stability of two light-cured and two dual-cured resin cements. Methods: The CIE-Lab color parameters (n=6) were measured immediately after sample preparation and at 7, 30 and 90 days of aging in distilled water. The color difference (ΔE) was calculated and then analyzed by three-way ANOVA for repeated measures and Tukey’s HSD test (α=0.05). Results: ΔE was higher for transparent resin colors, followed by dark and light colors. The mean values of ΔE were lower for both light-cured resin cements compared to the dual-cured cements. As the aging time increased, ΔE values increased. Conclusions: The light-cured resin cements showed greater color stability. The lighter shades of luting were more likely to display a greater color change.