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    1. Dental Hygiene
    2. Clinical Hygiene

    Exercise of the Month for April 2013

    April 5, 2013
    According to Bethany Valachi, PT, MS, CEAS, rotator cuff impingement is one of the most common musculoskeletal complaints among dental hygienists. But she says that the correction of a single working posture, plus a preventative exercise that targets the rotator cuff stabilizing muscles can help avoid this situation.

    VIDEO: External Shoulder Rotation

    Rotator cuff impingement develops from gradual wearing of the tendon that passes between the humerus and acromion process. In hygiene, this is often due to frequently lifting the arms away from the sides (Fig. 1) or moving the arm improperly.
    Abducted Arms Fo
    Fig. 1: Working with the arms elevated out to the sides can lead to rotator cuff tendonitis. Working with elevated shoulder postures of only 30 degrees can impede blood flow to the supraspinatus tendon, causing ischemia, as well as over-strengthening of the muscles that lift the arm. Hygienists are more prone to this problem on the left shoulder more than the right, probably due to positioning challenges and using the mirror to retract soft tissue. The patient must be positioned lower to avoid these elevated arm postures—a saddle stool is one way for hygienists to position the patient lower and attain more neutral working posture. Numerous other ergonomic interventions to achieve this are described in Chapters 2 & 4 of “Practice Dentistry Pain-free.” Muscles that lift, or abduct the humerus (supraspinatus and deltoids) must be balanced with the muscles that stabilize the humerus (infraspinatus, teres minor, and subscapularis) in the shoulder joint to allow proper movement and help to keep the tendon from becoming “pinched” between the humerus and acromion process. When properly balanced, the rotator cuff muscles rotate the head of the humerus in the shoulder joint when lifting the arm, keeping it centered and avoiding impingement. If, however, the stabilizing muscles are weak, or if the mover muscles become stronger than the stabilizing muscles, it causes the humerus to roll upward into the acromion and pinches the tendon in-between, resulting in damage to the tendon (Fig. 2).
    Impingement Fo

    Fig. 2: Impingement occurs when rotator cuff muscles become imbalanced.

    Because hygienists are uniquely prone to this rotator cuff imbalance, they must be aware that certain generic shoulder exercises and gym machines (that aren’t a problem for the general public) can worsen this imbalance and put them on the fast track to impingement. It is important to regularly target specific muscles that stabilize the rotator cuff. An example of one such exercise is the External Shoulder Rotation exercise (Fig. 3).

    Rotation Fo

    Fig. 3: Endurance training of the shoulder external rotators is an important preventative exercise for hygienists.

    Place a Theraband door anchor in a door that opens away from you at elbow height. Stand at a right angle to the door holding a small pillow or rolled towel between your elbow and your body. Squeeze your shoulder blades together then slowly rotate the arm outward. Keep the elbow pressed firmly against your side throughout the exercise. Repeat 10-20 repetitions on each side.

    An alternate method is to grasp the elastic band at both ends with hands at hip width apart. Press elbows closely to your sides. Slowly rotate hands outward, and return. If the resistance is too high, unwrap the band once on one or both hands. Be careful not to let the arms "fly away" from the sides during this exercise. This is why a towel roll or similar object under the arm is a good idea.

    Exercise Warning Fo
    View original video: Why Hygienists Require Specific Exercise
    Read more about proper patient positioning in dental hygiene.
    Bethany Valachi Fo
    Bethany Valachi, PT, MS, CEAS, is a physical therapist, dental ergonomic consultant, and CEO of Posturedontics, a company that provides research-based education. Clinical instructor of ergonomics at OHSU School of Dentistry, Valachi lectures internationally at dental meetings, schools, and study clubs. She covers 24 exercises for dental professionals in her new research-based exercise DVD, “Smart Moves for Dental Professionals On the Ball” Home Exercise DVD, available at www.posturedontics.com. Also included in the DVD kit are exercises that dental hygienists should avoid. Enter Discount Code OTB2013 upon checkout to receive RDH eVillage special discount. To read articles in RDH eVillage FOCUS written by Bethany Valachi, click here. To read about ergonomics and dental hygiene, click here.