RESUMO Introdução: Após a remoção dos braquetes, manchas brancas podem aparecer na área embaixo deles, as quais são o sinal clínico inicial da lesão cariosa. Existe um maior risco de cáries embaixo e ao redor das bandas e braquetes ortodônticos, o que exige a máxima utilização de procedimentos preventivos de cárie, usando diferentes métodos com aplicação de flúor. Objetivo: O objetivo do presente estudo foi avaliar alterações nas propriedades mecânicas (módulo de elasticidade e resistência ao escoamento), nas fases de carregamento e descarregamento de diferentes fios ortodônticos (níquel-titânio [NiTi] e níquel-titânio com adição de cobre [CuNiTi]), quando expostos rotineiramente a agentes profiláticos fluoretados, utilizados durante um período de tempo predeterminado. Métodos: Os fios pré-contornados retangulares de NiTi e CuNiTi foram imersos em solução fluoretada e saliva artificial (controle) durante 90 minutos a 37°C. Após a imersão, as amostras foram testadas utilizando-se um teste de flexão em três pontos, em uma máquina universal de testes. Resultados: Houve uma redução significativa na resistência ao escoamento na fase de descarregamento quando os fios de NiTi e CuNiTi foram expostos ao gel fluoretado. Conclusão: O resultado sugere que o uso tópico de agentes fluoretados afeta as propriedades mecânicas dos fios, levando a um aumento na duração do tratamento. Os agentes profiláticos fluoretados devem ser utilizados com cautela em pacientes submetidos a tratamento ortodôntico. O uso indiscriminado desses agentes pode causar efeitos corrosivos na superfície dos fios ortodônticos e consequente alteração das suas propriedades mecânicas.

ABSTRACT Introduction: After debonding, white spot may appear on the area below the bracket, which is the early clinical sign of carious lesion. There is increased caries risk underneath and adjacent to orthodontic bands and brackets, which call for maximum use of caries preventive procedures using various fluoride application methods. Objective: The aim of the study was to evaluate alterations in the mechanical properties (modulus of elasticity and yield strength) in loading and unloading phases for different orthodontic archwires (nickel-titanium [NiTi] and copper-nickel-titanium [CuNiTi]) when exposed routinely to fluoride prophylactic agents for a predetermined period of time. Methods: Preformed rectangular NiTi and CuNiTi wires were immersed in fluoride solution and artificial saliva (control) for 90 minutes at 37ºC. After immersion, specimens were tested using a 3-point bend test on a universal testing machine. Results: There is a significant reduction in the unloading yield strength when the NiTi and CuNiTi wires were exposed to APF gel. Conclusion: The result suggests that use of topical fluoride agents affect the mechanical properties of the wires, leading to increase in treatment duration. Fluoride prophylactic agents must be used with caution in patients undergoing orthodontic treatment. Injudicious use of these agents may cause corrosive effects on the orthodontic wire surfaces, with alteration in their mechanical properties.

Abstract In this study, we researched the chemical composition and the antifungal and antibacterial activity of volatile oil from Mentha spicata. The Gas chromatography/mass spectrometry (GC/MS) analysis of M. spicata showed that the main component was carvone (56.94%), followed by limonene (11.63%), sabinene hydrate (7.04%) and caryophyllene (4.06%). The antifungal activity of the volatile oil from M. spicata L. was determined with respect to plant pathogenic fungi, such as Fusarium oxysporum f. sp. radicis-lycopersici (Sacc.) W.C. Synder & H.N. Hans (FORL), Rhizoctonia solani J.G. Kühn. (R. solani), Alternaria solani (A. solani), and Verticillium dahliae Kleb (V. dahliae). The volatile oil was shown to have strong antifungal activity against plant pathogenic fungi. The result of the study was that at a dose of 12 μL petri-1, the volatile oil inhibited 100% of mycelium growth in V. dahliae, A. solani FORL and R. solani. Volatile oil exhibited remarkable activity against the selected bacterial strains of Xanthomonas spp. (ZI365, ZI366, ZI368, ZI370, ZI373, ZI375, ZI376, ZI378).

Resumen El objectivo del trabajo fue la investigación de la composición química, de la actividad antifúngica y antibacteriana del aceite volátil Mentha spicata. Desde el análisis Cromatografía de gases / espectrometría de masas (GC-MS), el componte principal M. spicata, resulta constituido por carvona (56.94%), limoneno (11.63%), hidrato de sabineno (7.04%) y cariofileno (4.06%). Se ha ademas detectado la actividad antifúngica del aceite volátil de M. spicata L. Contra hongos patógenos de plantas; Fusarium oxysporum f. sp. radicis-lycopersici (Sacc.) W.C. Synder & H.N. Hans (FORL), Rhizoctonia solani J.G. Kühn. (R. solani), Alternaria solani (A. solani) y Verticillium dahliae Kleb (V. dahliae). Se ha demostrado una fuerte actividad antifúngica del aceite volátil contra los hongos patógenos de plantas. El resultado del estudio, a una dosis de 12 μL petri-1, inhibió el crecimiento del 100% del micelio de V. dahliae, A. solani, FORL y R. solani. El aceite volátil exhibió una actividad notable contra las Xanthomonas spp seleccionadas (ZI365, ZI366, ZI368, ZI370, ZI373, ZI375, ZI376, ZI378) aislados bacterianos.

Forty-six bottled water samples representing 16 brands from Dhaka, Bangladesh were tested for the numbers of total coliforms, fecal indicator bacteria (i.e., thermotolerant Escherichia coli and Enterococcus spp.) and potential bacterial pathogens (i.e., Aeromonas hydrophil, Pseudomonas aeruginos, Salmonella spp., and Shigella spp.). Among the 16 brands tested, 14 (86%), ten (63%) and seven (44%) were positive for total coliforms, E. coil and Enterococcus spp., respectively. Additionally, a further nine (56%), eight (50%), six (37%), and four (25%) brands were PCR positive for A. hydrophila lip, P. aeruginosa ETA, Salmonella spp. invA, and Shigella spp. ipaH genes, respectively. The numbers of bacterial pathogens in bottled water samples ranged from 28 ± 12 to 600 ± 45 (A. hydrophila lip gene), 180 ± 40 to 900 ± 200 (Salmonella spp. invA gene), 180 ± 40 to 1,300 ± 400 (P. aeruginosa ETA gene) genomic units per L of water. Shigella spp. ipaH gene was not quantifiable. Discrepancies were observed in terms of the occurrence of fecal indicators and bacterial pathogens. No correlations were observed between fecal indicators numbers and presence/absence of A. hydrophila lip (p = 0.245), Salmonella spp. invA (p = 0.433), Shigella spp. ipaH gene (p = 0.078), and P. aeruginosa ETA (p = 0.059) genes. Our results suggest that microbiological quality of bottled waters sold in Dhaka, Bangladesh is highly variable. To protect public health, stringent quality control is recommended for the bottled water industry in Bangladesh.