Techniques of Instrument Disinfection
Clicnticul disinfectants. Many dental instruments cannot withstand the temperatures required for heat sterilization. Therefore if gaseous sterilization is not available and absolute sterility is not required, chemical disinfection can be performed. Chemical agents-with potential disinfectant
capabilities have been classified as being high, intermediate, or low in biocidal activity. The classification is based on the agent’s ability to inactivate vegetative bacteria, tubercle bacilli, bacterial spores, nonlipid viruses, and lipid viruses. Agents with low biocidal activity are effective only against vegetative bacteria and lipid viruses, immediate disinfectants
are effective against all microbes except bacterial spores, and agents with high activity are biocidal for all microbes. The classification depends not only on innate properties of the chemical but also, and just as important,
on how the chemical is used (Table 5-4).
Substances acceptable for disinfecting dental instruments for surgery include glutaraldehyde, iodophors, chlorine compounds, and ormaldehyde; glutaraldehydecontaining compounds are the most commonly used. Table 5-5 summarizes the biocidal activity of most of the
acceptable disinfecting agents when used properly. Alcohols are not suitable for general dental disinfection,
Table 5-3
Comparison of Dry-Heat versus Moist-Heat Sterilization Techniques
Sterilization Techniques
TABLE 5-4
Classification System for the Biocidal. Effects of Chemical Disinfectants
TABLE 5-5
Biocidal Activity of Various Chemical Disinfectants
because they evaporate too rapidly; however, they can be used to disinfect local anesthetic cartridges, Quaternary ammonium compounds arc not recommended for dentistry, because they are not effective against the hepatitis B virus and become inactivated by soap and anionic agents.
Certain procedures must be followed to ensure maxia disinfection, regardless of which disinfectant solution used. The agent must be properly reformulated added periodically, as specified by the manufacm
nts must remain in contact with the solui nated period, and no new contaminated o Id be added to the solution during thattime. All. instruments must be washed free- of blood or other visible material before being placed in the solution. Finally
After disinfection the instruments must be rinsed free of chemicals and used within a short period of time.
An outline of the preferred method of sterilization for selected dental instruments is presented in Table 5-6.
