Section 4. Examination of a dental patient

Chapter 13. Ergonomics in dentistry

Ergonomics (greek: ergon — work, nomos — law) — the science of adapting workplaces, objects, objects and working conditions in order to optimize it, based on the physical and mental characteristics of the human body. Its goal is to develop the shape of objects and provide a system of interaction with them that would be as convenient as possible for a person when using them.

Ergonomics is based on many principles — anatomy, physiology, hygiene, psychology, toxicology, and its main task is to create such working conditions for a person that would contribute to improving work efficiency, reducing fatigue, maintaining strength, health, and preventing diseases, including professional ones, and simply maintaining a good mood throughout the working day.

The term «ergonomics» was adopted in England in 1949, when a group of English scientists initiated the organization of the Ergonomic Research Society. Since the 1960s, the promotion of ergonomics in the work of dentists began, when special committees and laboratories were organized in many developed countries to coordinate the introduction of modern achievements of technical and biomedical sciences into the practice of dentistry. This was necessary, since the latest technical means, equipment, as well as modern methods of diagnosis and treatment were widely used in the daily work of doctors.

The dentist is subject to high concentration, emotional and muscular stress during work.

Prolonged static load of the doctor subsequently leads to undesirable changes in the musculoskeletal system, osteochondrosis. Uncomfortable posture and isometric muscle tension have an adverse effect on the health of the doctor and his assistant. Proper and ergonomic organization of your workplace and work process allows you to significantly save time, effort and, most importantly, health.

The concept of «ergonomics of work in dental practice» can be divided into three main components (fig. 13.1).

1. The position of the dentist and assistant, the placement of tools.
2. The position of the patient in the dental chair.
3. Technique of the dental assistant.

Fig. 13.1. Doctor's and assistant's work areas

Position of a dentist and assistant

According to modern research, the most appropriate method of ergonomics in dentistry is the method of work of a doctor and assistant, called «four-handed work». The doctor and assistant should work in the most comfortable physiological position that allows you to exclude or minimize irrational movements and manipulations, which reduces the load on the musculoskeletal system. All working surfaces of the dentist and the assistant must be at the same level at the distance of the doctor's or assistant's hand.

The concept of a divided space implies separate work areas for the dentist and assistant. Work areas are distributed as on the clock face. Twelve hours are in the head area of the patient, six hours are in the foot area of the patient.

• Zone 1 is located behind the patient's head. In the zone there are tools that the dentist touches with his left hand without moving the body.
• Zone 2 is located behind and to the right of the dentist, and he can reach it with his right hand.
• Zone 3 is located to the right of the patient's head, and the assistant reaches it with his right hand without turning the body.

The medical module should be located to the right of the patient. Behind the patient's head are the doctor's and assistant's worktables.

To clearly separate the working area of the doctor and assistant, the working area is divided according to the dial principle into 12 «hours». Doctor's segment: 9.00–12.00. Assistant segment: 1.00–3.00 (fig. 13.2).

Fig. 13.2. The «principle of the dial» separation of work areas (explanation in the text)

The doctor's chair should be positioned at such a height that the angle between the hip and the lower leg is equal to 105° (fig. 13.3).

Fig. 13.3. Dentist's chair

The assistant's chair is slightly higher than the doctor's chair to provide a good view of the oral cavity while working. The pedal is located under the patient's head. The doctor should get it out without changing the position that is convenient for him.

It is very important to try to maintain a neutral body position during treatment. This means that the angles between the shin and hip, between the forearm and shoulder should be straight. The head should be on the same vertical line as the spine. And the hands should be parallel to the position of the patient's body (fig. 13.4).

Fig. 13.4. Neutral position of the dentist's body

When the position changes, the load on the doctor's musculoskeletal system changes (fig. 13.5, 13.6).

Fig. 13.5. Recommended position of the dentist's head and back

Fig. 13.6. Recommended position of the dentist's shoulders and arms

When the doctor is in the «8 o'clock» position, sit opposite the patient so that the doctor's hips are at the level of the patient's shoulders. The right hand is located above the patient's chest, and the fingers of the left hand are located in the area of the right zygomatic bone and upper lip (fig. 13.7).

Fig. 13.7. Doctor's position when working in the «8 o'clock» segment

When the doctor is in the «9 o'clock» position, sit down so that the midline of the body is at the level of the patient's mouth. In this case, the legs are located under the headrest of the chair. The right hand is above the patient's right shoulder, and the fingers of the left hand are in the area of the right zygomatic bone (fig. 13.8).