ASEPTIC TECHNIQUE & LABORATORY ASEPSIS

Impressions and prostheses should be rinsed under gently running tap water to remove excess blood and saliva. All items that have been used intraorally (wax rims etc.) must be disinfected by immersion or by using the “spray-wipe-spray” technique. Stone casts must be immersed in hypochlorite or an iodophore. Dentures and impressions should be immersed in a disinfecting solution for the time recommended for TB disinfection. After the necessary immersion time has elapsed (check product directions) it is necessary to rinse the impression under running tap water to remove any residual disinfectant.

The following table can be used as a guide when selecting disinfecting solutions for impressions and prostheses:

  GLUTARALDAHYDES IODOPHORES CHLORINE COMPOUNDS COMPLEX PHENOLIC
Mixing Ratio: Manufacturer's Directions 1:213 dilution 1:10 Manufacturer's Directions
Impressions        
alginate - + + -
polysulfides + + + +
silicones + + + +
ployethers - - + -
hydrocolloid - + + ?
compound - + + -
Prostheses        
complete dentures
(acrylic/porcelain)
- + + -
removable partial dentures
(metal components)
- + #  

+ Recommended Method
- Not Recommended
# Could Damage Metal
? Insufficient Data

Note: Solutions must be prepared according to the manufacturer's recommendations for surface disinfection or immersion in disinfection. Sodium Hypochlorite diluted 1:10.

Warning: Materials vary in their response to chemicals. If damage or distortion occurs, shorten the immersion time or spray the impression, wrap in a paper towel and store in a sealed plastic bag.

Adapted from: Merchant V. Prosthodontics and infection control, Oral Health, November 1989. Vol. 79 No. 11 and Palenik C. & Miller C., Laboratory ascpsis: Disinfection of impression materials and microbially soiled dental prostheses. Quintessence of Dental Technology. 1990/1991.

Any instruments or materials to be used on new uncontaminated prostheses should be kept and used separately from those to be used with prostheses that have already been inserted in the mouth. Any laboratory equipment such as a bur which has come into contact with a denture that is being adjusted, repaired, or relined or otherwise altered must be cleaned and sterilized after each patient denture case using the method recommended on page 7 of this document. Exercise caution to ensure that no damage occurs to the prosthesis during the disinfection procedure.

Use an approved disinfectant solution (iodophore or sodium hypochlorite) in place of water in the pumice pan. It is advisable to have two pumice pans, one for use on new prostheses and the other for contaminated prostheses. If a single pumice pan is used on all dentures, the pumice must be changed after each case. If a separate pan is used for new prostheses only, that pumice should be changed daily.

Use only rag wheels which are autoclavable/sterilizable. Soak brushes and other non-sterilizable, non-disposable items overnight in an approved disinfecting solution such as glutaraldehyde, iodophore, complex phenolic or sodium hypochlorite. Some rag wheels can be autoclaved and should be sterilized when possible.

Countertops must be kept clean throughout the day and must be disinfected frequently, at minimum, at the end of each day. Clean and disinfect around sinks and taps daily. Clean and disinfect work pans each time a case is completed.

Any items that are being sent to a laboratory should be disinfected and packaged before it leaves the clinic. Any item returning from a laboratory should be disinfected immediately upon arrival.