Background
Work-related musculoskeletal disorders (WMSD) are common amongst dental personnel, who work in a restricted field that makes high demands on vision, and requires them to sit in a static or awkward posture, use excessive force, as well as undertake precise repetitive hand and wrist movements. Many studies have investigated the prevalence of WMSD amongst dentists. A systematic review on this topic focusing mainly on the pain experience found that the prevalence of WMSD ranged as high as 64% and 93%. According to the World Health Organization (WHO) and the National Institute for Occupational Safety and Health (NIOSH), the causes of WMSD are multifactorial including not only workplace conditions and workplace exposures but also organizational, psychosocial and sociocultural variables, amongst others. In our study the term WMSD refers to signs and symptoms arising due to series of micro traumas to bones, joints, ligaments, muscle tendons, blood vessels and nerves that accumulate and are intensified by work.
It is important to highlight this issue as WMSD in dentistry might contribute considerably to sick leave, reduced productivity and future possibility of leaving the profession at an early age. It was reported that dentists who suffer musculoskeletal symptoms are more susceptible to neuro-circulatory disease, including varicose vein, postural defects, and flat (foot) feet with subsequent effects on their general health and well being.
It has been suggested that injuries caused by WMSD, or similar cumulative trauma disorders, can be reduced or prevented by applying ergonomics in dental equipment and instrument design. Good ergonomic practices can prevent a number of WMSD conditions such as carpal tunnel syndrome. Adjusting the patient's chair when accessing different quadrants, placing instruments and materials within easy reach, working with elbows lower than shoulders have been advised to improve posture in a clinical environment thus minimizing fatigue and the risk of developing WMSD.
On the other hand, some studies have shown that musculoskeletal pain was negatively correlated with years of experience. It has been hypothesized that more experienced dentists learn to adjust their work posture to avoid such problems, or that those dentists with severe WMSD have left the profession. Therefore, this suggests that even dental students can manifest early signs of WMSD during their years of training. These findings were supported by research that revealed that more than 70% of dental students experienced neck, shoulder and lower back pain as early as the third year of their dental training.
Previously much of the focus regarding WMSD has centered on dentists and dental hygienists, while WMSD prevalence amongst dental students has not been thoroughly addressed in the literature. An assessment of the WMSD amongst the dental students and the underlying factors associated with it, is required to more clearly elucidate the nature of this important issue for dental students.
Therefore, the main objective of the present study was to assess the point prevalence of WMSD among dental students in their clinical and non-clinical years. The secondary objective of the study was to correlate the prevalence of WMSD of clinical-year students with the work characteristics during their training years. In addition to this, students' understanding of ergonomics and their capability for self-application during dental practice were also assessed. The aim of the study was to obtain this information which may improve the understanding of contributing risk factors thereby preventing early manifestation of WMSD.