Influence of time and exposure to air on radiographic contrast and relative film speed of three rapid dental film processing solutions.

The aim of this study was to determine the influence of exposure to air and time on the radiographic contrast and relative film speed of three processing solutions. A modified aluminium step-wedge phantom was used to expose varying numbers of Kodak Ektaspeed films daily for periods up to 57 days. The radiographic contrast and relative film speed were determined each day using a digital densitometer. Data obtained were analysed statistically, using Duncan's Multiple Range Test, and a 3-Factor ANOVA. It was found that, for radiographic contrast, Insta-Neg gave the highest values, followed by Kolchem and Ultra-Neg. For relative film speed, Kolchem gave the highest values, followed by Insta-Neg and Ultra-Neg. Both radiographic contrast and relative film speed decreased with the passage of time. Processing solutions kept in closed containers continued to perform efficiently for a longer time than those in open containers. The useful period was found to exceed that which is usually recommended.

Effect of dietary biotin supplement on equine hoof horn growth rate and hardness.

Over a 10-month period, 24 randomly selected riding horses were fed various amounts of biotin. Statistically significant improvements in growth rates and hardness of hooves were produced by biotin supplementation. Greater growth rates and hardness were achieved at a daily dose of 15 mg than at 7.5 mg. Increased hoof hardness was greatest in the hoof quarters and toe. No ring formation occurred in hooves of horses fed biotin intermittently.