Dentists are mostly aware of how to position themselves during treatment, however, the root of their problem seems to be related to dental chairs as they force patients into prolonged and awkward positions. Consequently, they must compensate for the difference in positioning by holding postures that place undue strain on their bodies (especially their back and neck). Dentistry is a profession with a high-risk factor regarding the development of musculoskeletal disorders due to the visual demands that necessitate the use of a static working posture. Headaches and vertebral pain have been found to be positively related to dentists’ poor ergonomic working posture.
When operating on the maxillary teeth in the dental upper arch, as an example, the location of the occlusal plane can force the dentist to hold an improper posture in order to have better access for the operation. Dentists and their assistants must be able to position the occlusal plane of the upper arch 20-25 degrees behind the vertical in order to maintain the most optimal working posture. Patients, on the other hand, cannot sit in this position for long periods of time because most double articulating headrests cut into the occiput, making positioning uncomfortable. To compensate for this, operators shift patients forward, sacrificing their own neutral posture in the process. As a result, the operator is forced to work in a forward, hunched position.
Another thing that can result in muscle imbalance is a forward-head posture which contributes to a rounded shoulder posture. When reaching for items, this posture may predispose the practitioner to supraspinatus tendon impingement (rotator cuff impingement). Furthermore, a static posture with the arms elevated by more than 30 degrees restricts blood flow to the supraspinatus muscle and tendon. Prolonged arm abduction can result in trapezius myalgia chronic pain and upper trapezius muscle trigger points. Some of the commonly held postures that lead to chronic pain in dentists include:
- Tilting to gain advantage point
- Lifted arms for long hours without support
- Holding one shoulder in an awkward position (either the round position or holding it up)
- Lumbar curvature reduction
- The angle between thighs that form due to having uncomfortable sitting and obstructed access
A rigid body attitude is not necessarily required for a balanced posture. The dentist has the freedom to move within certain boundaries so that no harmful positions are formed. The active balanced posture entails the dentist only using paravertebral muscles tonicity to keep the back straight (the physiological spine curvatures, also referred to as “S” spine form). The use of lumbar support provided by the seat distinguishes the passive balanced posture. Meaning that given the appropriate setting holding the proper posture would not be either restrictive or distracting.