Sodium fluoride and casein phosphopeptide-amorphous calcium phosphate cream plus sodium fluoride efficacy in preventing enamel erosion in a simulated oral environment study model.

Aim: The aim of this study was to evaluate the effectiveness of dentifrices containing high concentrations of sodium fluoride (NaF) and casein phosphopeptide‑amorphous calcium phosphate cream plus fluoride (CPP‑ACPF) in prevention of the erosion in a simulated oral environment study model. Subjects and Methods: Fifteen flat human enamel specimens were polished and half of the surfaces were protected with adhesive tape. Initial Knoop microhardness (KHN) and surface roughness (SR) were measured, and specimens were assigned to four groups: Control (placebo toothpaste – G1); CPP‑ACPF (G2), NaF 1450 ppm (G3), and NaF 5000 ppm (G4). Enamel surfaces were brushed 3 times daily in association with demineralization‑remineralization cycles (5s in cola drink + 5s in artificial saliva/10 cycles/twice daily) and the specimens were maintained in a salivary flow simulator apparatus. After 14 days, KHN and SR were measured again, and the enamel surfaces were analyzed by scanning electronic microscopy (SEM). Statistical Analysis Used: Data were analyzed using the two‑way ANOVA and Student–Newman– Keuls multiple range test (α =0.05). Results: All the tested groups presented a decrease in KHN after 14 days (P < 0.05). There was no statistical significance among materials tested. Significant increase in SR was observed for all groups. SEM analysis showed morphological alterations with honeycomb structures in enamel surfaces in the four experimental groups. Conclusions: It was concluded that tooth brushing with dentifrices with high concentration of NaF and CPP‑ACPF cream was not able to prevent enamel erosion in simulated oral environment.

Utilisation of respirometry to assess organic matter reduction of effluents from the Camaçari industrial complex (BA, Brazil)

The treatment efficiency of industrial effluents, after biological treatment by activated sludge in aeration tanks (AT), was assessed through the utilisation of respirometry tests at the Cetrel's-wastewater treatment plant (WTP). Samples of the equalised effluent (EE), prior to treatment, and of the treated effluent (TE), after treatment, were analysed. Twenty bioassays batch were carried out to AT (AT-2, AT-3 and AT-4). Each test consisted of: a basic test, a basic test with peptone added, a test using EE and a test using TE. The data showed that there was no statistically significant difference (p>0.05) in the respiration activity between the aeration tanks. Regarding the specific oxygen uptake rate there was a mean reduction of 70.8 percent between the tests performed with EE and TE. The results demonstratd that respirometry tests could successfully assess the efficiency of the activated sludge process and, therefore, be adopted as tool for the monitoring from the WTP.

Este trabalho avaliou, através de ensaios de respirometria, a eficiência do tratamento de efluentes industriais, após tratamento por lodo ativado em tanques de aeração (TA). Foram analisadas amostras do efluente equalisado (EE), antes do tratamento, e do efluente tratado (ET). Vinte baterias de ensaios foram realizadas com cada um dos TA (TA-2, TA-3 e TA-4). Cada bateria consistiu de um ensaio básico, contendo apenas o licor misto, um ensaio com adição de peptona, um ensaio com o EE e um com o ET. Não houve diferença estatística significativa (p>0,05) na atividade respiratória dos TA. Quanto à taxa de consumo de oxigênio específica houve uma redução média de 70,8 por cento entre os ensaios realizados com EE e ET. Os ensaios de respirometria determinaram com eficiência o nível de tratamento através de lodo ativado, e deve ser adotado no monitoramento dos efluentes da estação de tratamento de efluentes do Pólo Industrial de Camaçari.