ABSTRACT
This study evaluated urinary fluoride excretion by school children 4-6 years old who were living in a south Texas rural community that had concentrations of fluoride in drinking water supplies generally around the optimal level. We took supervised collections of urine samples in the morning and afternoon at school, and parents of the participating students collected nocturnal samples. We recorded the beginning and end times of the three collection periods and then determined the urinary volume and urinary flow for each of the periods. We measured urinary fluoride concentrations and calculated the urinary excretion rate per hour. The children had breakfast and lunch provided at the school, where the drinking water contained 1.0-1.3 milligrams/liter (mg/L) fluoride. Fluoride concentrations in the tested household water supplies, from wells, ranged from 0.1 to 3.2 mg/L fluoride. The children's average urinary fluoride concentrations found for the day were similar to those for the night, with means ranging from 1.26 mg/L to 1.42 mg/L. Average excretion was 36.4 mg/h in the morning, 45.6 mg/h in the afternoon, and 17.5 mg/h at night. The lower nocturnal excretion rates are easily explained by low urinary flow at night. Based on the 15 hours of urine collected, the extrapolated 24-hour fluoride excretion was 749 µg. In conjunction with similar studies, the data from this study will help in developing upper limits for urinary fluoride excretion that are appropriate for avoiding unsightly fluorosis while providing optimal protection against dental decay
Subject(s)
Humans , Male , Female , Child, Preschool , Urine , Drinking Water , Fluorides , United StatesSubject(s)
Fluoridation , Health Workforce , Health Programs and Plans , Oral Health , Periodontal Index , Saint Kitts and NevisABSTRACT
El colado en metal es conocido desde tiempos antiguos utilizando diferentes tipos y variedades en cuanto a costo, propiedades físico-químicas y biológicas. Todas estas cualidades las reune el titanio., lo que motivó el ser seleccionado para este estudio. Tomadas un total de 94 muestras se adelantaron procedimientos contenidos en el informe original. Efectuado el proceso en el TITANIOMER se fundió por medio de un arco eléctrico a 1.700°C. Se pesaron los metales y se estableció la relación cera-metal.