Clinical Foundations - Outcome 2

Question 1

3 Basic models of delivery for dental unit in treatment room

Answer 1

The dental unit must be easily accessible for both the operator and the assistant and can be set up in three basic models of delivery.

• Front delivery: positioned over the patient’s lap
• Side delivery: positioned at either side of the patient’s chair
• Rear delivery: positioned behind the dental chair

Question 2

Zones of Activity in Treatment Room

Answer 2

With each of the three types of delivery systems, there are designated zones of activity. The area around the patient’s oral cavity is divided into four zones of activity during dental treatment. The zones were established to promote effective ergonomics for both the dentist and the dental assistant. It is important to note that the zones are opposite for left- and right-handed operators. To locate the zones, you must first imagine that the patient’s head is the face of a clock. (i.e., mid-forehead is 12:00 and the chin is 6:00)

The Operator Zone
This zone extends from 7 to 12 o’clock for a right-handed operator and from 12 to 5 o’clock for a left-handed operator. This part of the circle is where the dentist can be positioned to gain access to areas of the mouth.

The Assistant Zone
The assistant’s zone is from 2 to 4 o’clock for a right-handed operator and from 8 to10 o’clock for a left-handed operator. In this area, there should be nothing to interfere with the dental assistant having access to instruments and materials used for the treatment being performed on the patient.

The Transfer Zone
This zone is where instruments and materials are transported to and from the oral cavity. It extends from 4 to 7 o’clock for a right-handed operator and from 5 to 8 o’clock for a left-handed person. This area is only used for the transfer of instruments and material and allows the dentist to keep his eyes on the treatment are

The Static Zone
This is a non-traffic area and is from 12 to 2 o’clock for a right-handed operator and from 10 to 12 o’clock for a left-handed operator. Equipment, additional cabinets, and dental materials used during treatment can be placed here.

Question 3

four-handed dentistry

Answer 3

process by which the operator and the assistant work together to perform clinical procedures in an ergonomically structured environment

Question 4

Ideal operator positioning

Answer 4

seated as far back as possible, with the front edge of the stool just touching the backs of the knees

thighs parallel to the floor, or knees slightly lower than the hips

feet kept flat on the floor and not crossed

backrest of chair positioned to support lower portion or small of back

height of chair maintained to keep operator’s forearms parallel to the floor when bent at the elbow

Question 5

Positioning of the Dental Assistant

Answer 5

seated back on stool
feet resting on base or foot ring of stool
positioned as close as possible to the patient’s oral cavity
hip at the patient’s left shoulder, and legs parallel to the patients chair towards the patient’s head
eye level 4 to 6 inches above operator

Question 6

Right Handed Dentist Zones (clock)

Answer 6

operator’s zone - 7-12 o’clock
transfer zone - 4 to 7 o’clock
assistant’s zone - 2-4 o’clock
static zone - 12-2 o’clock

Question 7

Left Handed Dentist Zones (clock)

Answer 7

operator’s zone - 12-5 o’clock
transfer zone - 5-8 o’clock
assistant’s zone - 8-10 o’clock
static zone - 10-12 o’clock

Question 8

objectives of efficient instrument transfer

Answer 8

• know the sequence of the procedure
  -anticipate when instrument transfer is required
• transfer instruments with the left hand, right is kept free to suction and to read the next transfer of an instrument
• transfer instruments with use of only class 1,2, or 3 movements (involving only fingers, wrist, or elbow)
• to transfer instruments in the position of use, which refers to directing the working end of the instrument downward for the mandibular arch and upward for the maxillary arch. This is so the dentist does not have to reposition
• to transfer an instrument so the dentist can grasp the instrument for its appropriate use
• to position an instrument in the dentist’s hand firmly, so the dentist can receive it without moving his or her eyes from the field of operation