We have assembled a glossary of terms for basic repairs to give you an idea about some of the internal workings of your dental unit. This will help you diagnose the parts to check and possibly replace if something goes wrong with your system. This system depicts industry standards. Our parts and accessories are interchangeable with most contemporary delivery systems.
The diagram below illustrates the basic principles of operation of most pneumatic dental delivery systems, rather than the specific operations of any one unit. If you have any questions, as always, feel free to contact our technical staff.
Delivery Unit Components
Automatic Handpiece Control Block (#49-87)
A valve that activates individual handpieces for use and routes air, coolant air, and water to each individual handpiece.
Automatic Handpiece Holder (#10-05)
A holder with a valve that is used in conjunction with the automatic handpiece control block to automatically activate an individual handpiece when removed from this holder. When a handpiece is removed from the holder, it terminates and relieves air pressure that is being applied on a diaphragm in the automatic handpiece control block. The constant air pressure holding the diaphragm down stops. The diaphragm relaxes and in turn opens the ports to that specific handpiece for use.
- Read more about the holder valves inside these holders in Practice Tip #108.
Handpiece Connectors (#12-02)
A connector and threaded nut used to screw your high-speed handpiece onto. These connectors also take swivel disconnects for your various handpiece models.
Foot Controls (#04-01)
A foot control is essentially a variable flow one way “valve” that supplies drive air to handpieces. Optionally, if the foot control has accessories, it can be used to control water on/off, etc.
- Read about the role of the foot control in Practice Tips #61.
Pressure Gauge (#07-11)
Gauge used to measure the amount of air pressure being delivered to your handpiece station. If it is in the junction box, it measures the air or water pressure to your delivery system.
- Read more about dental unit air pressure in Practice Tip #73.
Junction Box (#16-22)
The junction box consists of an area usually at the floor or perhaps on the wall. It is where the air, water and vacuum comes into the operatory. Oftentimes it includes an electrical box and your vacuum pipe too. Inside usually consists of: manual shutoffs, master on/off valves, regulators, and gauges for air and water.
- Read more about your utility center in Practice Tips #23.
Manual On/Off Valves (#49-90)
Manual valves control the main supply of air and water to delivery systems. These valves are connected to the main water or air lines. They turn on or off by manually turning a handle. This is considered the hard plumb.
- Read more about manual shutoff valves in Practice Tip #116.
Master On/Off Valves (#05-558)
Master valves provide on/off control of the main supply of air and water to delivery systems. They install directly to a manual on/off valve (at the hard plumb), and are remotely activated by an on/off relieving type of toggle valve.
Master On/Off Assembly (#05-54)
Assembly consists of a combination of a master, regulator, gauge, and filter all-in-one. It has adjustable (80 psi) and activates by a relieving type on/off valve (#05-02). Install it on a manual shutoff (#49-90) as a source for air or water.
- Read more about how these master valves have evolved over time in Practice Tips #99.
Water On/Off Relay Valve (#05-50, #05-52, or #05-51)
Relay valves supply water to the handpieces, water cup filler, and cuspidor bowl rinse. The valve activates using an on/off relieving toggle valve.
On/Off Relieving Type Toggle Valves (#05-02)
These toggle valves that when turned off also relieve air pressure from the tubing and valve system they connect to. This type of valve supplies air pressure to activate water relay valves, master on/off valves, arm assembly vertical brakes, and automatic handpiece control blocks. They must relieve in order to retract a diaphragm or pistol for on/off control in the specific valves they control as listed above.
- Read more about the role of the master on/off toggle in Practice Tip #127.
On/Off Non-relieving Toggle Valves (#05-01)
Non-relieving toggle valves do not relieve pressure from the tubing system they are connected to when they turn off. Normally used for water on/off control with systems that do not use a water relay valve.
- Read about the different kinds of toggle valves in Practice Tips #19.
On/Off Momentary Toggle Valves (#05-03)
Momentary toggle valves must be held in the “on” position and when released spring-back to the “off” position. These are often used for cuspidor cup fillers or for some purging systems.
Needle Routing Valves (#05-11)
Use a needle valve to variably control the flow of water or air. Normally used to control the amount of air or water coolant to the handpieces.
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