Over-the-Patient Delivery

This is the system most used in dental clinics today. This unit design meets the requirements of time and motion concepts and promotes good ergonomic positioning. With the unit over the patient, the assistant can easily retrieve the handpieces and transfer them to the doctor who does not need to remove his or her eyes from the operating site. There are no hoses to interfere with the assistant’s position. This type of unit has been designed for the practice of true four-handed dentistry. Also, if the dentist is working alone the handpieces are easily accessible.

Advantages

• The most ergonomically-sound system for the dentist
• Easily converts to left-handed or right-handed
• Moves up or down with the chair to maintain a constant relationship
• Provides the most practical use of space
• Allows dentist and assistant to handle instruments and switches
• Allows the dentist to release the handpiece without looking up

Disadvantages

• The most visible system to patients in terms of seeing the instruments
• Is very confining for patients
• Patients may bump into unit if they rise up suddenly
• Not generally recommended for treating children or patients with conditions that result in aggressive behavior or unpredictable movements
• Patient's feet can get tangled in the handpiece cords

Rear Delivery

The doctor must pick up the handpieces, which requires severe twisting and turning, since the doctor is forced to turn from the operating field to pick up the handpiece. Often it is necessary to transfer the handpiece from the retrieval hand to the operating hand. The units are mounted in a fixed position that cannot be moved to accommodate for the positions of the dentist or for ease of use for the assistant. HVE hosing and air/water syringes are permanently affixed to an assistant’s work area.

Advantages

• Least expensive system and easily combinable with an assistant cart for little additional expense
• Easily converts to left-handed or right-handed
• The least-visible system for patients
• Easy patient access to dental chair
• Allows handpieces to be transferred and burs to be changed by the assistant
• Easy to connect to in-wall utilities

Disadvantages

• Ergonomically less sound for the dentist, who must twist to reach handpieces or instruments
• Places the dentist at increased risk for sharps injuries from dental burs, due to the location of the handpiece holder near the dentist's forearm
• Cords can become tangled and difficult to position for efficient use
• Requires two entries to operatory--one for the dentist, and one for the assistant
• Makes working alone or standing up difficult for the dentist

Side Delivery

This unit has been a popular concept for many decades. In fact, most schools use this style of unit, often supplied with a bracket tray. This unit requires the dentist to pick up the handpieces so they must remove their eyes from the treatment site, twist and turn to grasp the instrument, and then refocus. The assistant can’t reach the instruments to exchange handpieces or change burs, reducing productivity that is gained from four handed dentistry.

Advantages

• Provides easy patient access to chair
• Less confining to patients
• Easy to connect to in-wall utilities

Disadvantages

• Most do not convert to left-handed and right-handed
• Handpieces inaccessible to assistant, so dentist must change burs
• Ergonomically less sound for the dentist, who must twist to reach for handpieces or instruments