How to clean, disinfect, and sterilize a dental operatory

Dental Assistant, The, Nov-Dec, 2004 by Curtis P. Hamann

Widely available from a number of manufacturers, glutaraldehyde is found in products with properties, e.g., buffered, potentiated, alkaline, acidic, etc. The percentage of concentration along with the temperature determines the time needed to achieve sterility. Glutaraldehydes are EPA registered as steriliant/disinfectant chemicals, effective at penetrating blood and bioburden. Most glutaraldehydes must be activated before use by adding an appropriate buffer. Activated solutions have an effective life of 14 to 30 days, depending on the product. Newer acidic potentiated (pH neutral) glutaraldehydes do not require activation. To measure appropriate strength of solutions, glutaraldehyde test strips are available. Manufacturers' instructions should be closely followed.

Slow acting, highly effective glutaraldehydes are not recommended for use on environmental surfaces. With glutaraldehyde as the active ingredient, products can contain other chemicals such as phenolic agents that alone are not rated for high-level disinfection. Hydrogen peroxide is a powerful oxidizing formulation that offers an alternative for high level disinfection and liquid sterilization. Some compounds use peracetic acid as a balancing agent. Hydrogen peroxide is virucidal, sporicidal, tuberculocidal, fungicidal, and bactericidal. Some find this type of product less irritating than glutaraldehydes; however, it can erode materials such as rubber, polyurethane, and polyethylene found in products such as mixing bowls, spatulas and some types of instruments. In addition, hydrogen peroxide can irritate skin and inhalation of vapors should be avoided.

Intermediate and Low Level

Alcohol-based products are low level surface disinfectants that must be used in conjunction with surface cleaners. When used for environmental surface disinfection, alcohol evaporates very rapidly leaving no residual kill capacity. It can damage adhesives, seals and certain plastics due to its drying effect. Alcohol-based disinfectants are not recommended for use in dental offices.

Synthetic phenolic compounds are EPA registered disinfectants with broad-spectrum disinfecting action including a tuberculocidal kill claim. If a surface has been thoroughly cleaned, phenols may be used for surface disinfection. Effective in the presence of detergents, they can be used on metal, glass, or rubber. Manufacturers of dental chairs caution against the use of phenols as they can damage or discolor upholstery. They can also erode plastic eyewear and face shields. Phenols leave a residual film on treated surfaces. Some diluted solutions must be prepared and discarded periodically according to their directions. Phenol-based compounds can irritate skin, eyes, and mucous membranes. Inhalation should be avoided.

Chlorine-based products are fast acting and economical intermediate level surface disinfectant. As an oxidizer, it has a strong odor and is corrosive to many metals. It is also destructive to fabrics and may cause plastic chair covers to fade and crack. Eye and skin irritation are drawbacks to using chlorine-based products. Only commercially available EPA-registered products are recommended in the CDC 2003 Guideline.