Taking care of your instruments

Sept. 1, 2004
What you need to know to protect your instruments and your patients

What you need to know to protect your instruments and your patients

Faulty instrument processing procedures could result in a multitude of problems in the practice. On the one hand, these risks are of infectious nature. Residual moisture on an instrument through insufficient treatment, for example, even without the presence of specific nutrients, can lead to the accumulation of potentially infectious pathogens. On the other hand, these risks can result in temporary or permanent material damage through the application of too high temperatures of disinfectant concentrations. This damage could impede or completely forbid further use of the instrument on patients. A correct processing of instruments is therefore required because of hygienic-infectious concerns, as well as material and technical requirements.

Testing, care, and wrapping before sterilization

In accordance with regulations, mechanically or manually cleansed instruments should be macroscopically clean. They must be free from blood, saliva, and other contaminants such as filling materials and caustic agents. To avoid metal abrasions, instruments must be cooled before testing their functions. Corrosion can be a consequence of metal abrasions. Hinges of instruments such as forceps, scissors, and needle holders must be oiled with an after-care substance of paraffin base before the function test. Due to the danger of patch formation, no silicone oil may be used. To be tested is whether or not the instruments fulfill their complete functions. Instruments that are blunt, bent, stained, or otherwise damaged must be weeded out. To check sensitive instruments (microsurgical instruments and periodontal instruments), the following special measures are to be applied:

1. Function check under the magnifying glass and

2. Storage in special racks or other suitable devices to avoid transport damage (safeguarding against friction, pressure, and slipping).

Amongst other things, causes of staining may be:

*Insufficient mechanical or manual cleansing and rinsing

*Medicament residues

*Inferior water quality

*Poor surface quality of instruments

*Unsuitable cleansing, disinfection, and after-care agents

*No observance of measurement instructions of cleansing, disinfection agents

*Polluted sterilizing steam

*Procedure error (omitted cleansing of brand new instruments before the first sterilization, etc.)

*Streaks from sterilization indicators

Flawless instruments of stainless steel should not come in contact with damaged surfaces (rusty instruments or those with flaked off chromium or nickel layer, etc.). Faulty instruments must be weeded out in order to avoid the resulting contact corrosion of rust-free instruments, sterilizing accessories and sterilizers as well as disinfection and cleansing machines. Also, using unsuitable sterilization wrappings can result in residual moisture remaining on the instruments, causing corrosion. Besides, the sterilization effect is endangered. Therefore, the sterilization wrapping must fulfill the valid norms regarding quality and usage, and be applicable to the chosen sterilization procedure.


Only fully desalinated or distilled water may be used in the steam sterilizer. The use of tap water leads to film coatings and corrosion damages to the instruments and sterilizer.

Salts are dissolved in all natural water. The types of water mineral contents - as well as their concentration - fluctuate in relation to the origin and type of drinking water. Potable water can exhibit an unduly high concentration of material contents, leading to patch formation or damage to instruments on sterilization. Particularly critical of water mineral contents are the hardness formers and chlorides. With water vapors, the material contents remain back as salt crusts. The lime from the water hardener forms water or scale stones.

Chlorides occur in all natural water in different concentrations. The relationships between the chloride of water and puncture corrosion are in most cases not foreseeable. Consequently, it is possible - due to unfavorable influences - that puncture corrosion can appear even with low water chloride concentrations. In order to avoid deposits and patches, particularly with mechanical sterilization, softened water is used. Because chloride is not removed from water by softening, it is advisable - with elevated chloride concentrations - to use fully desalinated water to avoid puncture corrosions.

Other material contents can - even in small concentrations - cause brown, blue, gray-black or other rainbow-colored staining. Such stainings can be elicited through compounds of iron, copper, manganese, magnesium, and silicon. Generally, in these cases, it is not a matter of corrosion. These stains can usually be removed by placing the instruments in instrument basic-cleaning agents according to the manufacturer’s instructions. Besides, the natural mineral water content sometimes turns up in potable water. This stems from corroded conduction systems. With sterilization, this rust deposits on instruments and produces rust flakes and, consequently, corrosion. This “alien rust” can be remedied by using fully desalinated water and (if need be) by conduction system renovation.


The sterilizer and sterilizing procedure must meet the valid norms and regulations. The complete function capacity of the apparatus must be ensured, and the service instructions and maintenance procedures of the sterilizer manufacturer must be accurately observed. The use of distilled water, proper sharpening, and lubrication, as well as following maintenance instructions for your autoclave will ensure long life of not only your instruments, but your sterilizer as well.

Cindy L. Hutcheson, CDA, COA, CDPMA, COMSA, FADAA, BS, is the chief executive officer of Hutcheson Clinical Consulting. She serves on the editorial board of the NADA Journal and previously served in the same capacity for the ADAA Journal. She can be reached at (888) 99-DENTAL or by e-mail at [email protected].

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