Posturedontics: How does dentistry fit you?

Dentists are at high risk for musculoskeletal disorders (MSD's) due to their work. MSD's is an umbrella term for number of injuries affecting different parts of the body, including joints, muscles, tendons, nerves that can arise from sudden exertion or making the same motions repeatedly. These injuries can develop over time and can lead to long-term disability. Dental professional often develop musculoskeletal problems due to bad working habits, uncomfortable physical posture causing unnecessary musculoskeletal loading, discomfort and fatigue. Ergonomic principles when it is applied, it will help to reduce stress and eliminate many potential injuries and disorders associated with the overuse of muscles, bad posture, and repeated tasks. This can be accomplished by using a proper dental chair, lighting and the selection of ergonomically-friendly equipment to fit the dental professionals physical capabilities and limitations. This review addresses about the basics of ergonomics, positioning, viewing, handling, and prevention of MSD's.

Dentist and dental hygienist are high-risk professionals to develop work-related musculoskeletal disorders (MSD's) compared to other health professionals. These disorders are characterized by pain and dysfunction of the neck, back, hands and fingers. It has been estimated that dentists are more susceptible to musculoskeletal injuries often occur in the neck, back, shoulders, elbows, wrists or hands.[1]

Musculoskeletal disorders are injuries that affect the human body's movement or musculoskeletal system (i.e., muscles, tendons, ligaments, nerves, discs, blood vessels, etc.). These disorders are considered to be work-related when the work environment and the performance of work contribute significantly, but are only one of a number of factors contributing to the causation of multifactorial disease.[2] Conditions can vary from mild recurrent symptoms to severe and incapacitating. Symptoms of MSD's can include pain, discomfort, aching, numbness, tingling, burning, stiffness, fatigue.[3]

These problems can be prevented by increasing awareness about the importance of the postures used during work, redesigning the workstation to promote neutral positions, examining the impact of instrument use on upper extremity and following healthy work practices to reduce the stress of dental work on the practitioner's body.[4]

Recently “Ergonomics” has become a popular term. The term has been used with most professions but increasingly in the dental profession.[5] In Greek “Ergo” means work and “Nomos” means natural laws or systems. Ergonomics, therefore, is the study of people's efficiency in their working environment. It is also a study of the relationship among the personnel, equipment and environment in the work area.[6] Working under good ergonomics conditions is the most beneficial way to reduce the chance of developing MSD's. Improving the ergonomic delivery of dental services and accounting for working conditions in dental offices enhance the well-being and safety of patients, staff and practitioners.[7]

Some Predisposing Risk Factor for Musculoskeletal Disorder[68]

Repetitive movements

Awkward postures

Standing or sitting in one posture for long periods of time

Poor posture

Poor postural muscle strength

Poor flexibility

Stress

Infrequent breaks

Inappropriate design of dental chair and magnification tools

Contact stress

Improper work habits

Genetics

Poor nutrition

Environment factor

Poor lighting

Vibration

Medical conditions.

Other Factors Unrelated to Dentistry that can Contribute to Musculoskeletal Disorder[6]

Home computer use

Increased activities involving fingers

Sports activities

Prolonged/awkward postures at home

Use of household tools

Subjecting to repeated activities like heavy lifting, bending, twisting or reaching.

Symptom[6]

Extreme tiredness in the shoulders and neck

Tingling, burning, or other pains in arms

Weak grip, cramping of hands

Numbness in fingers and hands

Clumsiness and dropping of objects

Hypersensitivity in hands and fingers.

Signs of Musculoskeletal Disorder[6]

Decreased range of motion

Loss of normal sensation

Decreased grip strength

Loss of normal movement

Loss of co-ordination.

Mechanism of Musculoskeletal Disorders in Dentistr[91011]

Dentist must consider the principles of ergonomics in his routine day-to-day practices in order to minimize the risk of developing MSD's. When a body is subjected to a static posture for a prolonged period of time, there is a reduction in blood flow to the tissues. Pain and tissue damage will result due to a reduction in the nutrient and oxygen supply with lactic acid and other metabolites accumulating.

This prolonged static posture can initiate a series of events that may result in muscle imbalances, ischemia, joint hypomobility and spinal disk degeneration.

The dentist must understand the mechanisms that contribute to MSDs so they can make informed choices regarding the use of an ergonomically designed equipment, change in the work posture and lifestyle. Applying this in the dental practice is the key to prevent and manage work-related musculoskeletal problems.

Classification of Musculoskeletal Disorder[91213]

According to Rundcrantz (1991) MSD's among dental practitioners can be classified as follows [Table 1]:

Table 1

Classification of musculoskeletal disorders

Preventive Strategies to Reduce Musculoskeletal Disorders in Dentistr[1213]

Although the causes of MSDs are varied and dependent to some extent on worker predisposing factors, anyone who is experiencing a MSD, wishes to minimize the risk of developing a MSD or who simply wants to improve comfort and efficiency. Interventions or prevention strategies require an awareness to manage and prevent injuries effectively. Applying ergonomics to the practice of dentistry provides safety benefits also improve performance objectives through greater productivity. One of the main goals of ergonomics in dentistry is to minimize the amount of physical and mental stress that sometimes occurs day-to-day in a dental practice. Of course, the effectiveness of any given intervention will depend on individual circumstances. Rather, the following interventions should be considered by the practitioner in light of his or her own experience and needs.

According to the International Standards Organization #6385 there are some core interventions applicable to every workplace:

Adapt workspace and equipment to account for operator and work being performed with preferred body postures

Provide adequate space in clinics for body movements

Provide variety in tasks and movements to avoid static muscle tension caused by postural constraints

Design work to allow machinery to do/assist highly repetitive tasks

Avoid extreme posture when exerting high force.

In addition to widely recognized general interventions, consider the following interventions as well:

Use of comfortable equipment

Early Treatment of MSDs

Posture and stools

Patient positioning

Hand instruments

Equipment layout

Delivery systems

Lighting and magnification

Gloves

Four-handed dentistry

Supervised exercise/stretching

Proper temperatures.

Use of comfortable equipment[14]

When purchasing new equipment, dentists should consider the ergonomic ramifications of the purchase and be aware that the term “ergonomically designed” could simply be a marketing ploy. There are, unfortunately, no industry standards. Consequently, dentists should develop an understanding of ergonomic risk factors and the concept behind ergonomic interventions to help them make more knowledgeable decisions about instrument and equipment purchases.

Early treatment of musculoskeletal disorders[15]

Early intervention is of the utmost importance. Early symptoms in the wrist and hand respond to conservative medical management that includes rest, icing, nonsteroidal anti-inflammatory drugs, and splints. In order to reduce the ill-effects of MSD's intervention should be provided at the initial stage.

Posture and stools[69]

Operator should maintain an erect posture by positioning chair close to the patient; one can minimize forward bending or excessive leaning over the patient

Place feet flat on the floor and adjust the seat height up until thighs gently slope downward while the feet remain flat on the floor

Each clinician who uses the chair should readjust it to fit his or her own body. A chair that is adjusted correctly for another person may be uncomfortable for you. Chair should have important feature like, adjustable height, width, tilt, backrest, seat pan and armrests

Saddle-style and tilted seats help avoid pressure to the posterior thighs and maintain the lumbar curve of the lower back by placing the pelvis in a more neutral position, which naturally balances the spinal curves.

Patient positioning[16]

While the patient's chair should provide support and comfort for the patient, it should also be adjustable to allow the operator to maintain neutral posture while working

Supine position – The position of the patient during dental treatment, with the patient lying on his or her back in a horizontal position and the chair back nearly parallel to the floor

The chair should be raised so the operator's thighs can freely turn beneath the patient's chair

Clearance around the patient's head should at least allow unimpeded operator access from the 7:00 to the 12:30 position, for right-handed operators

The headrest should stabilize the patient's head while allowing enough movement to position the patient and maximize access

For treating the maxillary second and third molars, the maxillary plane should be 25° beyond the vertical

For mandibular areas ask your patient to open the mouth and tilt the head downward. The term for this patient head position is the chin-down position.

Hand instruments[1718]

Design of the instrumentation can play a key role in the prevention of negative health effects for its users

Following table summarizes critical areas to consider when selecting new or evaluating existing instrumentation. [Table 2]

Table 2

Hand instruments design

Equipment layout[17]

Should be located in a manner, which allows you to maintain a neutral working posture

Should require minimum adjustment and effort so as to reduce postural deviation while working

Position the frequently used items as close to the point of use (22–26 inches for most people) and not above or below waist height.

Lighting and magnification

When properly selected and adjusted, lighting and surgical magnification can support balanced musculoskeletal ergonomics. Conversely, of course, improperly selected or poorly adjusted systems can contribute to, or may even create, unacceptable working postures[19]

The goal of overhead lighting is to produce even, shadow-free, color-corrected illumination that is concentrated on the operating field. Furthermore, the light source should be in the patient's mid-sagittal plane; directly above and slightly behind the patient's oral cavity; and 5 toward the head of the operator in the 12 o’clock position[20]

Use of fiberoptic lights on high-speed handpieces, followed by fiberoptic and LED lights attached to ultrasonic scalar units and dental mirrors resulted in improved visibility

Clinician can select a magnification device based on the available space, magnification requirements, and prior exposure to the device, learning curve and cost

e.g.: For magnification devices procedure scope, loupes, magnification lenses and dental operating microscopes.[8]

Gloves[1417]

Universal precautions mandate the routine use of gloves. Each dental healthcare worker must have gloves of proper size and fit. Although the influence of gloves on hand discomfort has yet to be explored, it is been indirectly cited as a potential contributor to carpel tunnel syndrome

Ambidextrous (i.e., nonhand specific): Exert more force than fitted gloves across palmar region of hand and may exacerbate symptoms of carpal tunnel syndrome (CTS)

Hand-specific (i.e., right vs. left) is recommended which fits better and places less force on hand.

Four-handed dentistry[14]

Dental assistants create a more efficient environment for the operator by eliminating unnecessary motion; decreasing twisting and turning movement; decreasing long reaches and unbalanced posture.

Chair side stretching exercises[1016]

Directional stretching involves a rotation, side bending or extension component

Resting hands frequently helps in preventing CTS

To relieve eyestrain look up from the task and focus eyes at a distance for approximately 20 s

Try head rotation for neck stiffness

Shoulder shrugging can be used to stretch the shoulder muscle by pulling it up toward the ears, roll them backward and forward in a circular motion

Aerobic exercise should be performed 3–4 times a week for at least 20 min. It increases blood flow to all the tissues in the body and improves their ability to use oxygen.

Proper temperatures[14]

It is recommended that hands and fingers be kept above 25°C or 77°F to avoid detrimental effects on dexterity and grip strength.

Conclusion

Overall this paper clearly demonstrates that MSD represent a significant burden for the dental profession. So the thorough understanding of the ergonomics is essential to know about the musculoskeletal problems that could arise because of improper ergonomics in dentistry. The clinician must optimize his/her working environment to help eliminate awkward postures, physical wear and tear and fatigue. Right ergonomics along with regular exercises, relaxation technique, proper nutrition helps us combat stress, thus converting the productive energy, thereby increasing comfort, improving the quality of life, ultimately leading to extended careers. This would enable the clinicians to work in a comfortable posture, to lead a healthy life and render appropriate care for the patients in need.