Back to the Basics: Infection Control Procedures

Over the past several months, our consultants have received many questions regarding infection control procedures for incoming work and other areas downstream of receiving.  So it seems time to do a little refresher on the subject.  The infection control areas to be discussed are receiving, model department, die trim and denture repair.

RECEIVING

Unfortunately, many of our clients are still receiving impressions with visible blood and bloody retraction cords and cotton rolls.  Communication between the dental laboratory and the dental office needs to occur to ensure that blood and other matter is removed from the items in the dental office prior to shipment to the dental laboratory.  If it’s not, then the laboratory needs to know how to deal with it.

The Centers for Disease Control recommends in their 2003 infection control guidelines for dentistry that cleaning should be the first step of any disinfection process.  The guidelines state “cleaning is a form of decontamination that renders the environmental surface safe by removing organic matter, salts and visible soils, all of which interfere with microbial inactivation.”  It is further stated in the guidelines that the disinfection process can be compromised if visible blood and inorganic and organic matter is not removed prior to disinfection.

Let’s take this and apply it to the preparation of incoming work in the dental laboratory:

Step 1: Wearing gloves, gown, mask, and safety eyewear, unpack containers received from the dental office.

Step 2:  Prior to discarding, decontaminate all packing material that has come into contact with items that have been in a patient’s mouth.

Step 3:  Rinse all items that have been in contact with the patient to remove blood and inorganic and organic matter.

NOTE:  Rinsing is also needed to remove any chemical residue that may remain on the appliance as a result of incomplete decontamination in the dental office prior to packaging and shipment.  A reaction between disinfecting chemicals could adversely affect the impression material.

Step 4:  Disinfect the items for the length of time required by the manufacturer of the chemical to deactivate TB.  The CDC recommends the use of a hospital-grade, EPA registered disinfectant with a tuberculocidal claim.  Time this process to ensure that the items remain wet for the appropriate length of time.

Step 5:  Rinse the items to remove the disinfectant.

NOTE:  When disinfecting models received from dentists, it is recommended that the model be rinsed immediately following the decontamination process.

MODEL DEPARTMENT

The two areas of concern in the model department are handling of partials imbedded in impressions and trimming back an over-extended border on an impression.

After separating a partial from an impression, it is recommended that the two surfaces that did not receive decontamination in the receiving area be decontaminated.

Technicians have indicated to me that it’s not unusual to expose blood and saliva during the trimming back process.  The technician performing this task must wear hand protection, safety eyewear, gown, and a mask just as in the receiving area.  After trimming back is completed, then disinfect the impression and the instrument used to cut through the impression material.

DIE TRIMMING OF CLINICALLY POURED MODELS

Prior to pouring the model in the dental office, the dental staff should decontaminate the impression, however, it is usually unknown by the technician if this decontamination has been performed.  The CDC indicates in their guidelines referenced above that movement of organisms from impressions onto casts has been demonstrated and that certain microbes may remain viable within the gypsum case for up to seven days.

In light of this, it is recommended that the technician be protected with appropriate personal protective equipment (PPE) when grinding on clinically poured casts.  Dust collection is usually used during the die trimming process, which will help reduce dust.  At the end of the workday, the areas used for die trim of clinically poured models must be decontaminated.

DENTURE REPAIR AND RELINES

These dentures are usually decontaminated in the receiving area, however, it is best to decontaminate at the end of the work day all work areas where this work was performed and all equipment used for denture repair and reline work.  This includes the pressure pot.

IN SUMMARY

Review your current procedures for infection control and ensure that you are protecting your workers in the receiving area by ensuring that they are wearing the appropriate PPE and that they are protecting their co-workers downstream of receiving by following stringent decontamination procedures.  Also, ensure that workers in the production areas listed above are decontaminating when necessary.

* Photo courtesy of Wanda Hincher, CDT

Do you have a question for Mary Borg? E-mail jdt@nadl.org.

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