'Occupational Therapy, Quinnipiac College, Hamden, CT 06518, USA b Dental Hygiene, Tunxis Community Technical College, Farmington, CT 06032, USA.
WORK A Journal of Prevention, Assessment & Rehabilitation
ELSEVIER
Work 8 (1997) 55-72
Ergonomic strategies for dental professionals Martha J. Sanders*a, Claudia A. Turcotte b 'Occupational Therapy, Quinnipiac College, Hamden, CT 06518, USA Hygiene, Tunxis Community Technical College, Farmington, CT 06032, USA
b Dental
Abstract This study examined the extent to which dental professionals have made changes within their practice environments to decrease the potential for developing a cumulative trauma disorder. A survey was disseminated to a sample of 95 dental professionals. The survey addressed the presence and location of pain, changes professionals made within their workplaces, and whether or not these changes were perceived as effective. Fifty two surveys were returned for a response rate of 55%. Results indicated that 96% noted pain during or after work; 88% had made changes in their work practices. Common strategies used to promote health were stretching, good posture, personal relaxation, and instrument maintenance. Use of ergonomic instruments, workstations, and new instrumentation strategies were seen as effective, but rated slightly lower than other categories. Copyright © 1997 Elsevier Science Ireland Ltd.
Keywords: Research; Ergonomic education; Carpal tunnel syndrome; Cumulative Trauma Disorders; Ergonomics; Dental
1. Introduction
The concept of applying ergonomic principles to dental hygiene is being widely embraced by dental professionals and health care professionals who specialize in injury prevention. The precipitating factors to this new pursuit are both the high incidence of cumulative trauma disorders (CTDs) in dental hygienists and the alarming number of dental professionals who report working with pain every day. In fact, studies report that 6.4-11% of all dental hygienists are diagnosed with carpal tunnel syndrome (McDonald et aI., 1988; Atwood and Michalak, 1992; Rice et aI., 1995). The prevalence of general musculoskeletal pain is much higher, ranging from 63 to 93% for
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combined low back, neck, shoulder, arm, and hand pain (Osborn et aI., 1990; Atwood and Michalak, 1992). While dental hygienists are generally aware of the potential for developing a cumulative trauma disorder, the degree to which dental hygienists have made changes to prevent musculoskeletal problems is not clear. This paper will briefly analyze the work of dental hygienists and the risk factors for cumulative trauma disorders specific to this profession. The impact of the current Occupational Safety Health Administration (OSHA) regulations on work practices will be examined in light of the implications for CTDs. The results of a survey on the current use of ergonomics strategies by dental hygienists will be presented. Finally, this paper will update healthcare practitioners on the ergonomic strategies and resources available to dental hygienists.
1051-9815/97/$17.00 Copyright © 1997 Elsevier Science Ireland Ltd. All rights reserved PlI S 1 051-9815(96) 00220-3
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2. Job analysis Dental professionals who deliver or assist in the delivery of oral health care include the dentist, dental hygienist, and dental assistant. All dental professionals report musculoskeletal pain during work. However, the incidence of such disorders is much higher in dental hygienists and dental assistants (Rice et aI., 1995). This discussion will highlight these latter two professions. 2.1. Overview Dental hygienists are responsible for providing preventive oral health care to dental clients. Dental assistants work directly with dentists, assisting them with instrument exchange and the preparation of dental materials (Torres and Ehrlich, 1995). Both dental professionals work under the jurisdiction of dentists in most states and therefore have varying degrees of autonomy over their work hours and numbers of clients seen. The primary role of dental hygienists is to perform intra-oral and extra-oral facial exams, remove calculus (tartar), plaque and stain from teeth, deliver fluoride treatments, expose radiographs, and educate patients. Dental hygienists may also participate in maintaining equipment, patient scheduling and treatment planning (Wilkins, 1994). Dental hygienists provide services to an average of ten clients per day, at 45 min each. However, this number may range from 8 to 14 clients per day depending on the setting and type of practice (Atwood and Michalak, 1992; Rice et aI., 1995).
gienist proceeds with 'scaling' to remove deposits of calculus on the teeth, and 'root planing' to smooth the root of the tooth. Finally, the dental hygienist may polish the teeth or simply floss and brush the teeth. The dental hygienist completes the visit with patient education and recording the client's status. The specific tasks of the dental hygienist may vary according to the needs of the client. 2.3. Workstation The majority of dental hygiene practitioners deliver client services from a seated position. Workstations involve the entire operatory set-up including the client chair, operating light, fixed or moveable instrumentation units (called 'delivery
2.2. A typical treatment session A prophylactic treatment ('prophy' or cleaning) typically begins with a medical and dental history and an extraoral exam. An extraoral exam consists of the dental hygienist palpating the head and neck area including the face, cheeks, and mandible of the client. The dental hygienist then completes the intra-oral exam, which involves an oral cancer screening, detection of tooth irregularities, and gently 'probing' alongside each tooth to detect hard and soft tissue loss. Once the exams are complete, the dental hy-
Fig. 1. The dental professional's workstation includes the client chair, operator stool, dental assisting cha ir, ope rating light, instrumentation units and co unter space .
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systems'), operator stool (dental hygienist's seat) and counter surface. (Please refer to Figure 1.) The instrumentation unit includes high and low speed handpieces, air-water syringes, ultrasonic and sonic scalers and an evacuation system to rid the mouth of saliva. The placement of the instrumentation unit in relation to the dental hygienist may be to the front, side, or to the rear of the dental hygienist. Some operatory set-ups include a combination of two or all three placement modes. Moveable stations allow dental hygienists to change positions throughout treatment sessions.
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hand and powered instruments to complete treatment (Fig. 2). Hand instruments include an assortment of small-diameter, cylindrical metal instruments with thin, angled tips at one or both ends. These instruments are designed to remove calculus and detect soft and hard tissue loss. Powered instruments include ultrasonic or sonic scalers and motor driven hand pieces. Ultrasonic scalers are mechanical vibrating instruments with tips used to remove tenacious calculus (tartar) and stain. Motor driven ultrasonic scalers operate at frequencies of 30 kHz, 115 volts and 50-60 Hz. Motor driven hand pieces are also vibrating instruments that polish teeth by removing stains.
2.4. Dental instruments 2.5. Instrumentation
The type and use of instruments strongly influences the pattern of musculoskeletal problems in dental professionals. Dental hygienists use both
The primary grasp used for instrumentation is called a 'modified pen grasp' (Fig. 3). To perform
Fig. 2. De ntal instruments include both hand and powered instrume nts. Common hand instruments are scale rs and curets. Powered instruments include ultrasonics and polishing instruments.
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Fig. 3. The primary grasp used for instrumentation is called the ' modified pen grasp'. The instrument is held between the thumb, index, and third fingers; the ring finger acts as a fulcrum for hand and forearm forces.
this grasp, the instrument is held between the thumb, index and middle fingers. The fourth finger is positioned in extension on an adjacent tooth, acting as a fulcrum that leverages hand forces (Wilkins, 1994). In proper instrumentation, the fingers guide the instrument yet remain in a static position on the instrument. The wrist and forearm motions power the stroke and therefore move constantly from flexion to extension within a range of about 50° in each direction; the forearm rotates from supination to pronation around the fulcrum of the fourth finger. The neck and shoulders remain in a static position to stabilize the body for this precise work. Probing involves a gentle up and down stroke next to the tooth; scaling requires short strokes with high forces to remove the calculus; rootplaning demands longer strokts and less force than scaling with more wrist and forearm motion to smooth the tooth root. A dental hygienist cannot always directly view every area of the mouth.
Therefore, a small mirror is used to view these tooth and gum surfaces. This practice, called indirect vision, alleviates the need for dental hygienists to severely flex their necks and twist their bodies in order to view various areas. In summary, dental hygienists and dental assistants use primarily small-diameter instruments and finely coordinated movements in order to accomplish their jobs. These professionals work in static head, neck, and shoulder positions for up to 45 min at a time. They additionally work with the potential stress of treating anxious clients. 3. OSHA impact In addition to the American Dental Hygiene A
