Decontamination of dental equipment. A validation of three devices designed for cleaning, disinfecting, and lubricating of dental high-speed turbines and handpieces.

This study deals with the decontamination of dental turbines and handpieces (DTH) aiming at eliminating the cross-infection risk in dental practice. Three types of equipment designed for cleaning/lubricating DTH were validated. The effect of the three devices was determined for four different types of DTH, which were artificially contaminated with Streptococcus salivarius ATCC 13419 in a controlled manner. Sampling was carried out by collecting one ml water flushed through the DTH connected to a dental unit. The study resulted in a model for testing the decontamination potential of a cleaning/lubrication device for DTH. One of the devices could not reduce the contamination, while two others were able to reduce the bioburden with at least 3.9 logarithmic steps. However none of the devices tested could constantly eliminate the contamination, for which reason an additional heat treatment of the DTH is recommended.

Long-term persistence of GAD activity in injured crayfish CNS tissue.

Crayfish CNS fibers were isolated in vivo from their cell bodies, from cellular connections in the CNS, and from peripheral sensory and effector cells. The glutamic acid decarboxylase (GAD) activity of the experimental tissues was about half of that of the sham-operated and unoperated control tissues by two weeks after surgery and remained at about that level during the ensuing six weeks. During that time, there was no significant behavioral, electrophysiological, or histological evidence of regeneration of nerve fibers across the lesion sites. The crush-isolated connectives possessed many intact axon profiles and non-neuronal cell nuclei. The long-term persistence of GAD activity in the injured CNS tissue may reflect the involvement of glial cells in maintaining neurotransmitter levels.