[Decontamination of dental unit waterlines using disinfectants and filters]. / Decontaminazione del sistema idrico del riunito mediante disinfezione e filtrazione.

Bacterial contamination of the dental unit water system can become a health problem for patients, particularly if they are immunodepressed. The present study has had the purpose of evaluating the effectiveness of methods of chemical decontamination using different disinfectants (peracetic acid, hydrogen peroxide, silver salts, chloramine T, glutaraldehyde T4) and methods of physical decontamination using synthetic membranes for the filtration of water. A preliminary removal procedure of the biofilm present in the waterline has been followed in a dental unit prepared on purpose for the research; subsequently different 2-week long maintenance procedures were applied using disinfectants injected by a pump and finally the bacterial contamination of the water flowing from the waterline was evaluated. The physical decontamination was performed using 0.22 mm membrane filters, which have been installed also in another dental unit, and the filtered water was analyzed to detect bacterial contamination. The preliminary procedure of biofilm removal succeeded obtaining germ-free water. Among the disinfectants used for the maintenance of the water quality only glutaraldehyde T4 was able to reduce the bacterial contamination under the limit suggested by the ADA. The membrane filter system was not able to purify the water, but when a disinfectant (peracetic acid) was used in the last part of the waterline good results were obtained. At present no decontamination system of dental waterline is available, and glutaraldehyde T4 seems to be the best disinfectant only if integrated with periodic biofilm removal for the maintenance of the water quality.

[Expert systems in medical emergencies]. / I sistemi esperti nell'emergenza medica.

Computers have already been introduced into the field of medical applications and many support systems have been developed. Recently expert or knowledge-based systems have been employed in some specific fields. A project for the creation of an expert system for use in toxicological emergencies is presented. This system is designed to give the physician continuous support and to employ computer formulae as similar as possible to medical reasoning. For this reason, medical knowledge was examined and the event graphs, frames and production rules to represent it were chosen.