system components and cause the failure of your dental unit. A 750ml bottle constructed of polyethylene plastic is used to hold the water for the system. The bottle cannot be heat sterilized, but can be sterilized using ethylene oxide. Before attempting to use a self-contained water system, read the manufacturers instructions for operation and maintenance.
A large central air compressor in your clinic provides compressed air. This enables most dental units to operate up to three dental handpieces and the 3-way syringe. Because of the noise level and for safety reasons, this system is located outside of the patient treatment area.
Most dental handpieces operate on air pressure within 20- to 80- pounds per square inch (psi) range, with a specific pressure recommended for each handpiece.
Most units have a type of control system located on the bracket tray where air pressure can be adjusted. If you locate any air leaks, have a DET correct them as soon as possible.
Probably the most complex system on a dental unit is the electrical system. When there is a problem with this system, report it to the DET. Among the items affected by a dental unit's electrical system are the water heaters and solenoids (electrically operated switches).
Generally, a central vacuum system provides suction to numerous dental units. The vacuum is connected to the unit with hoses and oral evacuation equipment, such as high-volume evacuator (HVE) and saliva ejector. A filtering component of the central vacuum for both the HVE and saliva ejector is the solids separator (fig 11-4). It contains a strainer which collects large pieces of debris that could clog suction hoses. At least once a week or if a decrease in vacuum is detected, remove and clean the strainer. This ensures proper suction from the central vacuum and maintains proper DTR infection control.
HIGH-VOLUME EVACUATOR. - The water spray from the handpieces and three-way syringes, along with debris from the patient's mouth, must be removed. The most efficient way to do this is with an
Figure 11-4.Solids separator.
HVE (fig 11-5). The principle of this evacuator is low pressure and high volume.
A tip is placed into the HVE handpiece and the suction turned off and on by a control valve or button on the handle. Some of the newer models of HVEs have a quick disconnect device and are now autoclavable. Follow the manufacturers instructions for maintenance.
During certain procedures, the provider may choose to keep the working site dry by using the saliva ejector. This type of suction is effective only when there is a limited amount of fluids, such as saliva, to remove from the patient's mouth. It can also be used to hold the tongue away from the working site and keep an area dry for placement of material that takes a long time to set A disposable plastic saliva tip inserts into the rubber end of the saliva ejector assembly and is turned on/off by a control valve. Follow the manufacturer's instructions for maintenance.
Figure 11-5.High-volume evacuator (HVE). 11-9