Effectiveness of an educative ergonomic plan in reducing musculo-skeletal disorders among dental practitioners

Faculty of Dental Sciences. Bengaluru, India. ABSTRACT Objective: Work related musculo skeletal disorders (WMSD) are very common among dental practitioners who use precise hand-wrist motions and prolonged static postures. The aim of this study was to develop an educative ergonomic plan and test its effectiveness in reducing symptoms of musculo-skeletal disorders among dental practitioners. Material and Methods: This study was conducted on a random sample of 50 dental practitioners of both genders (25 male, 25 female) practising for more than 4 years in urban Bengaluru, India and showing symptoms of neck pain, back pain or wrist pain. In the first round of the questionnaire data was collected from all 50 dentists. Next an educative ergonomic plan was developed which included simple exercises and recommendations in the form of do’s and don’ts. The study population were asked to follow the guidelines given and perform the exercises given in the poster daily for a period of 3 months. Then, the questions were again asked. The differences in responses during the first stage and second stage were analyzed. Results: The use of the ergonomic plan led to a statistically significant improvement in certain ergonomic practises such as practise of changing their positions during clinical practice, keeping shoulders and arm at correct level while working instruments within hand There a use of the ergonomic plan. Conclusion: The ergonomic plan in the form of recommendations and exercises were an effective tool in improving ergonomic practises and reducing the symptoms


Sabrish S et al.
Effecti veness of an educati ve ergonomi c pl an i n reduci ng muscul o-skel etal di sorders among dental practi ti oners Sabrish S et al.
Effectiveness of an educative ergonomic plan in reducing musculo-skeletal disorders among dental practitioners INTRODUCTION E r g o n o m i c s i s d e f i n e d a s a s e t o f multidisciplinary knowledge applied to the organisation of labour activities and elements that make up a job [1]. In Greek, "ergo" means work and "nomos" means natural laws or systems [2]. Ergonomics modifies the work to meet the needs of people, rather than forcing people to accommodate the work [2]. The clinical practise of dentistry requires a great amount of clinical skill as well as theoretical knowledge. The clinical skills in dentistry are developed through years of practise and this practise entails fine motor skills and repeated movements of the clinician's hand, wrist, neck, back etc [1,3]. Dentistry itself demands a compromised working posture owing to the fact that the working area has limited access and indirect vision is often used [4,5]. There is always a neutral zone of movement for every joint and muscle. Injury risks increase whenever work requires a person to perform tasks with body segments outside of his or her neutral range in a deviated posture [6]. Musculo skeletal disorders (MSD) or work related musculo skeletal disorders (WMSD) are very common among dental practitioners who use precise hand-wrist motions and prolonged static postures. Spine, shoulders, elbows and hands are the most likely areas of the body to be involved [7]. 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 [8]. The onset of these MSDs can progress to a severe condition if care is not taken at a proper time. A systematic review focusing mainly on the pain experience found that the prevalence of WMSD in dentists ranged as high as 64% and 93% [9]. Musculoskeletal disorders account for 29.5% of the reasons for early retirement among dentists [10].
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 [11]. 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 [12]. Several detailed guidelines have been provided to diagnose and prevent MSD among dentists [2,5]. This should be part of the education curriculum for dental students. Although the condition is common, there is very low awareness about methods to prevent them [1]. The reporting of musculoskeletal symptoms by dental students as early as the first year of the dental program suggests that ergonomics should be covered and taught as part of the dental curriculum to reduce risks of WMSD in the future [8]. A majority of students (92%) reported minimum participation in workshops related to ergonomics in dentistry and 77% were unfamiliar with treatment and remedies available in the case of WMSD [8]. Students have also reported to have knowledge regarding ergonomics and are aware of its importance for occupational health. However, they have difficulty adopting ergonomic postures [13]. Therefore, ergonomics improvements, health promotion and institutional interventions are needed for reducing the risks for WMSD. Hence there is a need to improve the knowledge and practices among students and dentists. It has also been recommended to perform specific exercises for trunk, shoulder, hands, head and neck on regular basis to prevent these disorders [14].
The aim of this study was to develop an educative ergonomic plan in the form of a poster with exercises and recommendations and to test its effectiveness in reducing musculo-skeletal disorders among dental practitioners in urban Bangalore, India.

METHOD AND MATERIALS
The study was a questionnaire study with convenience sampling method conducted over a period of 3 months. A random sample of 50 dental practitioners of both genders (25 male, 25 female) who were willing to participate in the study were considered. Inclusion criteria were: Dentists practising for more than 4 years in urban Bengaluru and showing symptoms of neck pain, back pain or wrist pain. Exclusion criteria were practitioners who were under any pain medication, pregnant, suffering from any medical conditions like bone disorders, hypothyroidism, and with a history of trauma, fracture of wrist, etc.
The questionnaire was prepared by consulting specialists (Orthopedician and Physiotherapist) in the field. In the first part of the study, the 50 dental practitioners selected were given the questionnaire. The questionnaire is shown in Table 1.

Sabrish S et al.
Effecti veness of an educati ve ergonomi c pl an i n reduci ng muscul o-skel etal di sorders among dental practi ti oners

Sabrish S et al.
Effectiveness of an educative ergonomic plan in reducing musculo-skeletal disorders among dental practitioners In the next stage of the study an ergonomic plan (educative poster including exercises and recommendations) was developed.
Initially a review was done of the literature on musculoskeletal disorders and ergonomics among dentists from pubmed and scopus indexed journals, reference books and other authentic sources. [1][2][3][4][5][6][7][8][9][10] The information was critically reviewed to summarize practical techniques and exercises for better ergonomics. An educative poster was developed which included simple exercises and recommendations in the form of do's and don'ts. The poster was validated with subject experts. An orthopedic surgeon and a physiotherapist were consulted for validation. Method used for validation was PEMAT-P (Patient Education Materials Assessment tool for printable materials [15]. The contents of the poster was as follows-(exercises and recommendations) WRIST EXERCISES:- Figure 1 A) Spider push up -Start with your hands together in prayer position. Spread fingers apart as far you can, then separate your palms and bring fingers together. Repeat ten times.    DONT'S -Avoid arching of your back. Avoid lifting shoulders in strained position. Don't keep patient's chair too high. Avoid tilting head to one side only for longer durations. Avoid overflexion of the spine. Avoid working with elbow too high in relation to shoulder. Avoid extreme wrist deviation from side to side. Avoid excessive wrist movements.
Once the poster and recommendations were prepared the next stage the study was conducted. The study sample were given the poster prepared

Sabrish S et al.
Effecti veness of an educati ve ergonomi c pl an i n reduci ng muscul o-skel etal di sorders among dental practi ti oners

Sabrish S et al.
Effectiveness of an educative ergonomic plan in reducing musculo-skeletal disorders among dental practitioners and the ergonomic recommendations. The study design is shown in Figure 3. The study group of 50 dentists were asked to follow the guidelines given and perform the exercises given in the poster daily for a period of 3 months. At the end of this phase, the dentists were again asked to answer the questionnaire. The differences in responses during the first stage and second stage were analyzed and are presented. The compliance of following the plan was recorded in a chart.
The data collected was saved in an excel chart. Statistical Package for Social Sciences  Table 2 present the distribution of study participants according to age. 62% were in the age range of 20-30 years.

RESULTS
In this study 94.0% of the sample reported that they were familiar with the ergonomic postures to perform clinical procedures in dental practice at the pre intervention phase. 70% of the sample reported that they were had some musculoskeletal pain due to dental practice at the pre intervention stage but after the intervention this number increased to 87.5%. The difference was not statistically significant. Table 3 presents the area or region where they felt pain. Table 4 shows the rating of the pain levels.
16% of the sample experienced pain during or after using vibrating instruments (high speed handpiece) and even after the intervention there was no statistically significant difference in this response. 32 subjects (64%) reported that they frequently change their positions during clinical practice and this changed to 48 samples after the intervention and this change was statistically significant as seen in Table 5.
30% of the sample reported that they kept their shoulders and arm high while working and this changed to 22.2% after the intervention and this change was statistically significant as seen in Table 6.   Effectiveness of an educative ergonomic plan in reducing musculo-skeletal disorders among dental practitioners The responses to questions 16, 17, 18 and 19 in the questionnaire did not give much differences when comparing the pre and post intervention data. Only 22% of the sample reported that after finishing clinical practice they performed stretching exercises at the pre intervention stage. This changed to 70.3% after the intervention and this change was statistically significant as seen in Table 7.
72% of the sample reported that their instruments were within hand reach and they didn't make strenuous movements before the intervention and this changed to 76.6% after the intervention and this change was statistically significant as seen in Table 8.

DISCUSSION
As shown in Table 2 the age distribution of study participants varied from 20 to 60 years and majority were in the age range of 20-30 years. The sex distribution was equal. Hence this study focussed on younger practitioners with a minimum of 4 years of experience.
94.0% of the sample reported that they were familiar with the ergonomic postures to perform clinical procedures in dental practice at the pre intervention phase and this changed to 100% of the sample at the post intervention phase. This showed that the participants were conscious of the increase in their knowledge on the topic as a consequence of participating in this study. The probable reasons for not following the ergonomic practises earlier could be a poor understanding of ergonomics theory; a gap between the theoretical discipline and its clinical application; and a working environment unsuitable for ergonomically correct dental work [1]. Our study correlates to another study where it was found that knowledge of ergonomics postural requirements and their clinical application among the dental students surveyed were not satisfactory [1]. In another study among dental students in Malaysia they found that majority of students (92%) reported minimum participation in workshops related to ergonomics in dentistry and 77% were unfamiliar with treatment and remedies available. They also advised that theory and practice of ergonomics should be incorporated into the dental undergraduate curriculum [8].
Our study also made similar recommendations based on findings among dental practioners in India. In another study done it was found that 84.6% of all students surveyed suffered from Effectiveness of an educative ergonomic plan in reducing musculo-skeletal disorders among dental practitioners MSD associated with the clinical requirements of their training [16]. This finding suggests that oral health professionals may have an increased risk of developing MSD during their education and training, well before the beginning of a professional career. There is a requirement for the inclusion of ergonomics in the dental curriculum, and also stressing theoretical knowledge and practical implication during various dental procedures [17].
A statistically significant reduction in pain levels was seen after the use of the ergonomic plan. This reduction was seen across the participants who had higher pain levels (between 5-10). This suggests that the combination of ergonomic exercises and practise recommendations is an effective method to reduce the symptoms of MSD among practitioners and this suggestion is supported by similar literature [5]. A probable reason for this effectivveness could be that the poster was prominently displayed in the clinical area which acted as a reminder to the clinicians to follow the principles. Hence development of an exercise regimen such as that used in this study should prove to be a significant factor in reducing these disorders. Such practises ought to be ingrained in the training and curriculum. 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 [18].
The limitations of this study is that it had a small sample size based on convenience sampling and a cross sectional design and hence cannot relate specific practises to development of MSDs. The data collected relied on self-reporting by the dentists and could lead to over or under estimation of the pain and the related injuries or recall bias. Compliance was checked using selfassessment in a chart but there could have been bias in reporting of compliance.

CONCLUSION
The ergonomic plan in the form of recommendations and exercises were an effective tool in improving ergonomic practises and reducing the symptoms of musculoskeletal disorders among dental practitioners. There is a requirement for the inclusion of ergonomics in the dental curriculum.