As practitioners know all too well, dentistry involves the kind of awkward static poses and repetitive movements that can lead to injury and pain. Cumulative trauma disorder — when your body accumulates small injuries more quickly than it can repair them — can lead to a variety of issues, from difficulty gripping instruments to pain or numbness in affected areas.
Good ergonomic positioning is key to avoiding these kinds of injuries, but maintaining proper posture can be a challenge — especially given the range of movements and stances required by a typical day of dentistry. That makes the use of ergonomic equipment and careful attention to both clinician and patient positioning essential to enabling and reinforcing healthy work postures.
While many products claim to be ergonomic, not all actually are, which means it's important to get data and research supporting any ergonomic claims before purchasing equipment. But even true ergonomic equipment will only help you protect your body when used correctly. Proper positioning is crucial to ensure your office facilitates healthy work practices, regardless of your equipment's ergonomic status.
To help you get started, we’ve outlined a checklist of steps dental professionals can take to make sure their offices are as conducive as possible to a healthy work environment:
- Check that your operator stool is adjusted correctly. That means making sure your stool's backrest supports your lower back, that its seat pan is the appropriate depth, that its armrests are set so you're not elevating your shoulders and that its height allows you to sit with your thighs sloping slightly downward. If you're considering a saddle stool, make sure it fits the curve of your spine. Saddle stools can cause pain for some people with certain kinds of lordosis.
- Recline your patient appropriately. When looking at a patient's lower arch, they should be reclined in their chair to within 10 to 20 degrees of a fully supine position. They should be fully supine when examining the upper arch.
- Adjust the orientation of your patient's occlusal plane to help you practice good posture. Situating your patient so that their occlusal plane is 20 to 25 degrees behind the vertical allows you to examine them while maintaining an upright, neutral posture. Getting them in that position will require some additional cushioning, though. Have your patient scoot up until the end of their head is flush with the end of the headrest. Then, place ergonomic cushions in their cervical curve, lumbar area and at their knees to ensure comfort. Wheelchair, pediatric and geriatric patients may all need additional adjustments.
- Adjust the height of your patient's chair. It's important that you’re able to reach your patient with your forearms angled upward no more than 10 degrees without elevating your shoulders.
- Rotate your patient's head. This can be a big help with positioning. For chairs with a flat headrest, encourage patients to give their head a side bend.
- Pay attention to your clock position. Your line of sight needs to be perpendicular to the tooth surface or quadrant you are examining, and you should aim to be in the 11 o'clock to 12 o'clock position 70% of the time. That means you'll need space in your office to operate in that position — ideally having at least 20 to 22 inches of clearance between the headrest and any obstruction like a counter or a delivery system. Choosing the right chair is also key to enabling good clock positioning. Chairs with wide wings, for instance, can inhibit close positioning, whereas chairs with narrow upper backrests and thin headrests typically allow easier access to the oral cavity.
- Have your delivery system nearby. Over-the-patient delivery is perhaps the best method from the perspective of the clinician's posture, as it allows them to reach all the instruments and handpieces from any clock position without turning and twisting. The one potential downside is that having the equipment in the patient's sightline could heighten their anxiety. Rear delivery systems work best for four-handed dentistry, where an assistant is making the instrument transfers and changing the burs on handpieces so that the dentist isn't having to twist around to swap out equipment. For hygiene, rear delivery also works well, provided hygienists retrieve instruments with their off hand and transfer them to their dominant hand. In addition, side delivery works for hygiene and four-handed dentistry, but hygienists must remember to keep the delivery system close at hand.
- Place your lighting appropriately. New guidelines from Dr. Lance Rucker at the University of British Columbia, School of Dentistry, recommend that your overhead light should parallel your line of sight as closely as possible. That means it should be slightly behind and to one side of your head. A head-mounted light is also very effective, as it most closely parallels your line of sight.
- Remember to use a finger fulcrum on your non-dominant side. It is common for dentists and hygienists to have more pain in their non-dominant shoulder than their dominant one, which suggests that while practitioners are good at finger-fulcruming on their dominant side, they sometimes forget to use a finger fulcrum on their non-dominant side.
- Practice your head posture. This is particularly important given that many dental loupes are non-ergonomic. To practice maintaining good posture while using a non-ergonomic loupe, put the loupe on and look straight ahead while holding your thumbnails together at a little above waist-level to approximate the position of the patient's oral cavity. Next, shift your gaze downward without moving your head and then dip your chin slightly until you can see your thumbs. Maintaining this posture when using your loupe will reduce stress at the C5-C6 vertebrae, which is where disc herniation often occurs.
- Alternate between sitting and standing. Even a simple decision like choosing to stand whenever doing injections will help make sure you are regularly changing positions, which can aid in preventing lower back pain.
No one wants their body to force them to retire before they're ready, but the repetitive and physical nature of dentistry means practitioners are at risk of suffering debilitating, sometimes irreversible injuries. Every team member, from assistants to hygienists to dentists, is susceptible to developing pain on the job. Appropriate positioning — of clients, of clinicians and of equipment — is key to ensuring a safer operatory. Paying careful attention to posture and proper ergonomic positioning can help ensure a long and healthy career.