UCLA Infection Control Manual

Dr. Andy Wong

A variety of sterilization methods and many types of liquid chemical disinfecting agents are available. Heat sterilization is preferable for all materials and equipment that can withstand high temperatures.

Dental Treatment Facilities (DTF's) should have a Central Sterilization Room (CSR) or central sterilization facility. The critical elements of CSR design are:

1. Dedicated Work Areas. These areas must include work areas for receiving, cleaning, processing, sterilizing, storing, and issuing.

2. Functional Flow of the Sterilization Process. Materials and equipment must flow from receiving to issue without physically retracing or impinging on a preceding step or area. Contaminated items are not to be processed in an area common to the handling of sterilized items.

3. Traffic Control. Pre-sterilization and sterilization areas are to be off limits to anyone not involved in the sterilization process.

4. Receiving and Cleaning. Ideally, this area will be physically separate from the sterilized area. Use of appropriate equipment such instrument cassettes and ultrasonic cleaning units will minimize handling of contaminated materials and instruments.

5. Processing. Ample work surface is critical. All inspecting, sorting, wrapping, and packaging of contaminated materials occur here.

6. Sterilization.Certified sterilization units are mandatory with regular sterilization testing and periodic maintenance.

7. Sterile Storage and Issue. Physically separate storage and issue areas from contaminated processing and sterilization areas.

A. The Management of Contaminated Instruments. Take contaminated instruments directly to the receiving area of the CSR following a patient's treatment. Do not unnecessarily handle contaminated instruments or materials in the DTR's or other patient treatment areas.

B. Instrument Cleaning. Break down packs and place disposable items and soiled linen in appropriate containers. Immerse instruments in an EPA registered, ADA approved pre-soak before any additional handling. Process instruments using one of the following methods, listed in order of preference:

1. Ultrasonic Cleaning. Safer and more effective than manual scrubbing. Always use baskets in and covers on ultrasonic units. Solutions must be capable of removing protein, blood, and other debris and be changed daily or when visibly soiled.

2. Automated Washer Processing.While convenient, most washers cannot clean as effectively as ultrasonic cleaning can. Automated washing after ultrasonic cleaning is preferred.

3. Manual Scrubbing. While wearing general purpose utility rubber gloves, face mask, plastic apron, hair cover, and eye protection follow the following sequence:
   1. pre-rinsing in running water
   2. soaking in pre-soak solution.
   3. washing and scrubbing with long-handled brush.
   4. final rinsing.

C. Drying - All washed items should be allowed to dry, dried by dry heat or hand-dried using disposable paper towels.

D. Pre-sterilization steps:

1. Inspect and sort instruments.

2. Dip instruments requiring special attention in rust inhibitor.

E. Wrapping and Packaging:

Critical and semi-critical instruments shall be packaged before sterilization if they are not to be used immediately. Properly manage by:

1. Use of trays, cassettes or bags.
2. Opening all hinged instruments.
3. Wrapping loosely to allow steam or dry heat to circulate freely throughout the pack.
4. Using chemical heat sensitive indicators.
5. Labeling packs with dated processing labels.

E. Sterilization Methods

1. Steam Heat Sterilization
   1. Arrange all packs loosely in the chamber.
   2. Use perforated or mesh bottom trays.
   3. Follow manufacturer's instructions on sterilizers and sterilizing agents.
   4. Biological monitoring at least weekly.
   5. Maintain a consolidated sterilization log for CSR sterilizers containing sterilizer identification number, sterilization dates, duration and temperature of cycle, operator's name, biological monitoring results, repair and preventive maintenance dates, and a synopsis of actions taken.
   6. Allow all sterile bags, trays, and packs to cool on a wire rack before moving to storage areas to prevent condensation formation. Resultant contamination may be due to the warm packs on a cool surface.

2. Dry Heat Sterilization: Sterilization time depends on temperature. A typical dry heat cycle is 30 minutes at 320 degrees F, plus the time required to bring the load up to temperature. Be sure to follow the manufacturer's instructions.

3. Chemical Vapor Sterilization: Requires 20 minutes at 270 degrees F.

4. Ethylene Oxide Sterilization. Follow manufacturer's instruction on existing equipment.

5. Liquid Chemical Sterilization. Treat these products as high level disinfectants rather than sterilants because it is impossible to adequately monitor the effectiveness of this sterilization technique.

A. Heat stable critical and semi-critical instruments shall be cleaned and sterilized before use.

B. Surgical and all hand instruments.

C. Handpieces, sonic scalers and tips, low speed motor attachments.

D. Burs and Diamonds. Clean in an ultrasonic cleaner and dry before sterilizing. Screw-cap glass tubes are recommended with heat sterilization using biological and chemical indicators to monitor.

E. Gates-Glidden Burs and Endodontic Files. Arrange set in gauze packs or endodontic file holder and seal in peel packs before autoclaving. Restock and dry heat sterilize file storage boxes weekly. Broaches are used once and discarded into a sharps container.

F. Rubber Products. Use steam or dry heat on heat stable rubber and use ethylene oxide or chemical on non-heat stable rubber. Prophy cups are used once and discarded.

G. Extracted Teeth for Pre-clinical Laboratory Course. Submerge teeth in 10% buffered formalin solution for at least two weeks in tightly sealed jars. Before use, rinse the teeth thoroughly while wearing utility gloves.

A. Types of sterilization monitoring:

1. Process Indicators. Usually in tape form to distinguish processed packs and trays from those that have not been cycled.

2. Chemical Indicators. Chemical dyes on strip that change color are placed inside an instrument pack to determine whether the conditions necessary for sterilization have been met.

3. Biological Monitors. Also known as spore-testing, bacterial endospores are used to determine the effectiveness of sterilization.

B. Guidelines for Biological Monitoring:

1. Monitoring should occur at least weekly.

2. Test Procedure. Use a biological monitoring system compatible with the specific sterilization method. While processing a normal load, place monitors in an instrument pack and subject the load to a normal sterilization cycle. Monitors should be used according to manufacturer's directions. Use unprocessed biological monitors for controls.

3. Evaluation Criteria. Designated, trained personnel must evaluate the results. A test is satisfactory if control monitor is positive and the test monitor is negative. If a CSR log is maintained, make appropriate log entries.

4. Positive Test Monitor Results:
   1. Notify your Clinic Director or Supervisor.
   2. Make proper log entries if CSR log maintained.
   3. Re-sterilize all packs processed since the last negative test.
   4. Notify the repair department for corrective action.
   5. After corrective repair action, re-test the sterilizer using biological monitors to confirm negative results.
   6. Review the sterilization log for recent repairs or maintenance, if CSR log is maintained.

C. Guidelines for Process & Chemical Indicators:

1. Use chemical indicators inside and process indicators outside each pack. Screw top test tubes for burs if used must have internal indicators.

2. Follow manufacturer's instructions when reading the processed indicators.

3. Only biological monitoring can identify whether or not sterilization has actually occurred.

D. Liquid chemical disinfectant or sterilants cannot be biologically monitored, and therefore are used as high-level disinfectants.

*The shelf-life of a packaged item is event related and depends on the quality of the wrapping material, the storage conditions, the conditions during transport, and the amount of handling. These expiration times are provided as a means of setting uniform standards.

*Specifically not recommended due to difficulty in eliminating air from packs.

PERIODONTICS INFORMATION CENTER