Effect of composition and curing type of composite on adaptation to dentin cavity wall.
Adaptation to dentin cavity wall of three marketed and eight experimental composites was investigated by measuring polymerization contraction in cylindrical dentin cavities and by SEM observation. The cavity adaptation of light cured composites was always inferior to that of the chemically cured composite and, in the experimental composites, the optimum filler content was obtained.These facts indicate that cavity adaptation is affected significantly by the flow of the composites from the free surface into the cavity during polymerization.
The Effect of EDTA-containing Surface- active Solutions on the Morphology of Prepared Dentin: An in vivo Study
The capacities of EDTA-containing and surface-active antibacterial solutions and their combinations for removing amorphous smear layers produced by cutting of dentin were studied in vivo on 132 human dentin surfaces ground at high speed with a diamond point. A combination of 0.2% EDTA and surface-active antibacterial solutions removed most of the smear layers without opening too many tubule apertures or removing peritubular dentin. No difference was found between the cleaning capacity on surfaces ground under water cooling compared to air cooling.
Prevalence of lice on dairy cattle in England and the bordering counties of Wales
A postal questionnaire was used to collect information on the prevalence of lice on cattle on a random sample of dairy farms in England and the bordering counties of Wales. Replies were received from 1040 (52.8 per cent) of the 1970 farms which were mailed. Fifty per cent of farmers reported having ever seen or suspected lice in their herds and 29 per cent reported possible infestations in the winter of 1996/97. Visits were made to 24 farms in the south west of England during February 1998. Twelve of the farmers said that they had seen or suspected lice in their herd since October 1997, and that lice were more frequently observed on the adult cattle. However, examination revealed lice on 18 of the 24 farms, and adult cattle were the least likely group to be infested.