Ergonomics: Health Implications for Dental Hygienists

1. Ergonomics: Health Implications for Dental Hygienists Dr. John H. Park, DC, CSCS Progressive Spinal & Sports Rehab 10076 Darnestown Road Suite 200 Rockville, MD 20850 www.ProSpineRehab.com

2. Overview: Ergonomics and Health Implications for Dental Hygienists • Increase awareness • Decrease work-related pain and injuries • Heighten productivity • Improve musculoskeletal health • Increase comfort • Improve quality of life • Extend careers

3. What is Ergonomics? • Ergonomics is the study of workers and their relationship with their occupational environment • How you position yourself, your patient, how equipment is utilized, how the workplace is designed and how it impacts your health • ERGONOMICS is a way to work smarter, more efficiently with less effort and discomfort to the human body

4. Studies show work-related pain in the dental field is not decreasing Over half of all dental professionals continue to experience work-related pain Why? The physically challenging nature of the work with numerous risk factors Risk Factors Prolonged Static Postures Repetitive Movements Working in a confined space Challenges with positioning yourself or the patient Limitations with the tools and equipment used Ergonomics in the Dental Health Field

5. Ergonomics: The Human Factor • People Are Different We come in different shapes and sizes yet the workplace is often set up for “one size fits all” • People Have Limitations We have physical and mental limits for working - The wrist cannot tolerate excessive extension - The back cannot tolerate excessive bending or twisting - The neck was not meant to be in constant flexion - Muscles will fatigue if under constant tension

6. Consequences of Poor Ergonomics • Fatigue • Pain/Discomfort • Illness/Injury • Missed days at work • Errors • Lower productivity • Patient dissatisfaction

7. Physical Signs Decreased range of motion Deformity Decreased grip strength Loss of muscle function Symptoms Pain Numbness Tingling Burning Cramping Stiffness Poor Ergonomics: Signs and Symptoms

8. Poor Ergonomics = Musculoskeletal Disorders The World Health Organization definition: Musculoskeletal Disorderis “a disorder of the muscles, tendons, peripheral nerves or vascular system not directly resulting from an acute trauma or instantaneous event” Two Most Common Causes for Musculoskeletal Disorders in the Dental Health Profession Cumulative Traumas Prolonged Static Postures

9. Cumulative Trauma • Repetitive Movements like Scaling and Polishing are Cumulative Traumas • Vibrations transmitted by dental handpieces or mechanical scalers are Cumulative Traumas • Cumulative Traumas add up These microtraumas cause “wear and tear” on the muscles, tendons, and nerve tissue

10. Prolonged Static Postures • Human body was designed for movement • Dental hygiene procedures means practitioners must maintain static postures • Hygienists hold postures that require more than 50% of the body’s muscles to contract to resist gravity • Muscle overload leads to decreased blood flow and increased pressure on the muscles and joints

11. Static Postures leads to Muscular Imbalances • Muscles responsible for rotating the body to one side become tighter (shorter), while opposing muscles become weaker (longer) • Right handed hygienists repeatedly assume NECK ROTATION TO LEFT with SIDE-BENDING TO RIGHT to gain better visibility • Problems with NECK ROTATIONTORIGHT with SIDE-BENDING TO LEFT

12. Static Postures=Muscle Ischemia • As postures deviate from neutral, muscles contract harder to maintain working postures • During static muscle contraction, the vascular supply to muscle and surrounding tissues is restricted • Results in depleted nutrient and oxygen supply (ischemia) • Lactic acid and other metabolites accumulates causing pain and tissue damage

13. Trigger Points and Myofascial Pain Disorders of Neck Degenerative Joint Disease (Arthritis) Thoracic Outlet Syndrome Tendinitis Carpal Tunnel Syndrome Trigger Finger Nerve Entrapment Syndromes Lower Back Pain Sciatica Cumulative TraumasandProlonged Static Postures Lead to Musculoskeletal Disorders

14. Myofascial Pain: Trigger Points • Trigger Points: groups of muscle fibers that are in a constant state of contraction inside a tight band of muscle • Feels like a knot or a small pea in muscles, and when pressed on can refer pain to distant parts of the body • Ischemic areas are susceptible to the development of trigger points

15. Myofascial Pain:Trigger Points

16. Static Postures: Degenerative Joint Disease • Synovial fluid, which lubricates the joints, is produced each time a joint moves • Lack of movement and contracted muscles from static postures reduces the synovial fluid production, resulting in joint hypomobility • This loss of mobility leads to degenerative changes and more musculoskeletal disorders

17. Static Postures: Degenerative Joint Disease Symptoms • Intermittent/chronic pain and stiffness • “Creaking” or “cracking” of joints • Swelling in the joints • Loss of motion in the joints • Increased pain with activity or use

18. Neck and Shoulder DisordersThoracic Outlet Syndrome • Condition resulting from compression of the nerves, arteries, and veins as they pass through from the neck to the arm (thoracic outlet) • Possible causes: tight scalenes, cervical rib, tight pectoralis muscle, traumas • Often misdiagnosed

19. Neck and Shoulder DisordersThoracic Outlet Syndrome Symptoms • Pain in the neck, shoulder, arm or hand • Numbness and tingling of fingers • Muscle weakness/fatigue • Cold sensation in the arm, hand or fingers

20. Cumulative Trauma Injury: Tendinitis • When tendons slide back and forth through their sheaths friction is created • As with any other moving part, enough friction can cause wear and tear along with inflammation • When tendons or sheaths swell, and there is pain and tenderness

21. Wrist Tendinitis • Pain, swelling and inflammation on the thumb side of the wrist • Made worse with grasping and twisting activities (polishing and scaling) • Occasional “catching” or snapping when moving thumb

22. Carpal Tunnel Syndrome • Compression of the Median Nerve as it passes through the Carpal Tunnel • Caused by pinching and gripping activities with the wrist bent • Made worse with repetitive flexion and extension activities at the wrists

23. Carpal Tunnel Syndrome Symptoms • “Pins and needles” in the hands and fingers • Pain in the thumb, index and middle finger • Limited range of motion at the wrist • Pain radiating up the arm • Decreased grip strength • More pain at night

24. Trigger Finger (Tenosynovitis) • Sustained forceful grips and repetitive motion irritates the tendon and tendon sheath (tenosynovium) • Nodules form in tendon causing warmth, swelling, tenderness of the tendon • Pain occurs during movement that place tendons in tension • Fingers lock in “Trigger Position”

25. Cubital Tunnel Syndrome • Prolonged use of the elbow while flexed or trauma from overuse can compress the Ulnar Nerve • Pain, numbness, tingling and impaired sensation in the little and ring fingers, side and back of hand • Loss of fine control • Reduced grip strength

26. Guyon’s Syndrome • Compression of ulnar nerve in Guyon’s canal at the base of the palm • Caused by repetitive wrist flexing or excessive pressure on palm/base of hand • Pain, weakness, numbness, tingling, burning in the little finger and part of the ring finger • Symptoms may worsen at night or early morning

27. Upper Crossed Syndrome • TightLevator Scapulae Upper Trapezius Scalenes Pectorals • WeakMiddle/Lower Traps Rhomboids Serratus Anterior Deep Neck Flexors • Elevated shoulders • Forward head postures • Jutting shoulder blades • Neck Pain and Upper Back Pain

28. Low Back Pain • Low Back Pain is the leading cause of occupational disability in the dental healthcare profession • Studies show that low back pain is clearly related to seated postures and sitting duration

29. Low Back Pain: The Problem with Sitting • With seated postures, pressure in the lumbar disks increases by 50% from standing • Unsupported sitting causes 2x more axial loading in the spine than standing • During forward flexion and rotation (a position often assumed by dental hygienists) the pressure increases by 200%

30. Low Back Pain:Disc Degeneration, Bulge and Herniation • Spinal discs provide for flexibility shock absorption • Discs are composed of tough outer layer (annulus fibrosis) and gel-like center (nucleus pulposis) • When weight is applied to the disc, the nucleus expands outward and puts pressure on the annulus fibrosis

31. Low Back PainDisc Degeneration and Herniation • Sitting while flexing forward compresses the discs in the front • Uneven pressure on the disc leads to disc bulging and herniation • When the disc bulges or herniates backwards the nerves can become pinched

32. Low Back Pain: Sciatica • Pain from lower back or hip radiating to the buttocks and legs • Leg weakness, numbness, or tingling • Commonly caused by prolapsed intervertebral disc pressuring the sciatic nerve • Worsened with prolonged sitting or excessive bending and lifting

33. Low Back Pain:A Vicious Cycle • People with back problems seem to be faced with this vicious cycle • There is considerable evidence that bed rest and passive treatments have limited value • We now know that activity and the right kind of exercise are critical to treating back pain

34. Lower Crossed Syndrome • TightHip Flexors Lower Back Muscles • WeakAbdominal MusclesGluteus Maximus • Swayback - excessive curve of the lower back • Anterior Pelvic Tilt - hips tilted forward • Lower Back Pain

35. Preventing Ergonomic Injuries • Move • Change Position • There is no one “correct” posture best for an entire working day • The Human Body Needs Change and Mobility

36. Preventing Ergonomic InjuriesStretching Guidelines • Never stretch to the point of pain or discomfort • Do not bounce or use quick, jerky movements • Stretch should be performed every half hour

37. Suboccipital Muscles • Deep muscles at the base of the skull responsible for protraction, rotation, and tilting of the head • Suboccipitals become shortened with forward head postures • Common cause for headaches

38. Levator Scapulae • Primary function is to elevate the scapula • Also bends the neck to the side • Tightens up when carrying a bag with a strap or talking on the phone

39. Scalenes • Functions to stabilize the neck during lateral movements • Aids in inspiration • Becomes tight with awkward leaning positions while seated

40. Trapezius • Upperelevates the shoulders • Middleretracts the shoulder blades • Lowerrotates the shoulder blade downwards • Becomes tight with elevated arm postures

41. Pectoralis Minor • Functions to draw the shoulder blade forward and downward • Tight in people with a rounded shoulder posture • Shortened pec minor is a possible cause for Thoracic Outlet Syndrome

42. Wrist Flexors/Extensors • Prime function is to flex and extend the wrist • “Tennis Elbow” is pain on the lateral side of elbow • “Golfer’s Elbow” is pain on the medial side of the elbow

43. Hamstrings • Main function is to bend the knee • Secondary role in extending the hip • Weak low back and glute muscles increases tightness in the hamstrings • Prolonged seated postures also causes tight hamstrings

44. Iliopsoas • Primary function is to flex the hip (bring thigh up towards the abdomen) • People with chronic lower back pain often have very tight hip flexors • Commonly shortened with prolonged seated postures

45. Piriformis • Main function is to externally rotate the hip/thigh • Shortened in people who sit for long periods of time • “Piriformis Syndrome” causes compression of the Sciatica nerve

46. Questions and Answers