The guidelines mentioned above in combination with a well-designed dental unit allow you to sit, see and work well – all at the same time.
Mandal3 determined that the healthiest sitting position is what he called “the upright balanced position”, with an angle of around 120 degrees between thighs and upper body. In this position, the spine retains its natural curve preventing extended pressure on the intervertebral discs.
The dental assistant’s head should be at the same horizontal level as your head while working. If you are taller, the assistant may use a stool with a foot ring to increase their horizontal position.
Please note that the upright balanced sitting position requires a higher position of patient chair, hand instrument table and worktop than the traditional position with horizontal thighs!