Physical workload in neck, shoulders and wrists/hands in dental hygienists during a work-day

Musculoskeletal Disorders in the Clinical Practice of Dental Hygienists and Dentists, Prevention and Awareness among Italian Professionals: Focus on Enlarging Systems

(1) Background: Musculoskeletal disorders of the upper limbs are a common medical condition among dental hygienists and dentists, making them a common occupational risk for dental professionals. The purpose of the work was to collect information about the dental professions and their habits to highlight what can be good practices to be carried out to prevent any musculoskeletal disorders. (2) Methods: To identify habits and problems inherent in the professional activity of dental hygienists and dentists, a questionnaire was formulated on the use of enlarging systems. (3) Results: The questionnaire was completed by 241 dental professionals. As for the use of magnifiers, 72.6% of participants use them: among dental hygienists, 67.8% use magnifiers, among dentists, 80.9% use magnifiers; there is a statistically significant difference. There is no statistically significant difference between professions regarding muscle disorders. (4) Conclusions: For a clearer assessment, it would be appropriate to submit the questionnaire to a wider sample of professionals, to define better the correlation between musculoskeletal disorders, work activity and the type of enlarging systems used.

Consistency between the ACGIH TLV for hand activity and proposed action levels for wrist velocity and forearm muscular load based on objective measurements: an example from the assembly industry

Objectives. This study aimed to investigate the consistency between results of the American Conference for Governmental Occupational Hygienists (ACGIH) threshold limit value (TLV) for hand activity and proposed action levels of objective measurements in risk assessments of work-related musculoskeletal disorders. Methods. Wrist velocities and forearm muscular load were measured for 11 assemblers during one working day. Simultaneously, each assembler's hand activity level (HAL) during three sub-cycles was rated twice on two separate occasions by two experts, using a HAL scale. Arm/hand exertion was also rated by the assemblers themselves using a Borg scale. In total, 66 sub-cycles were assessed and assigned to three exposure categories: A) below ACGIH action limit (AL) (green); B) between AL and TLV (yellow); and C) above TLV (red). The median wrist velocity and the 90th percentile of forearm muscular load obtained from the objective measurements corresponding to the sub-cycles were calculated and assigned to two exposure categories: A) below or C) above the proposed action level. Results. The agreement between ACGIH TLV for hand activity and the proposed action level for wrist velocity was 87%. Conclusions. The proposed action level for wrist velocity is highly consistent with the TLV. Additional studies are needed to confirm the results.

Effect of a Novel Adaptive Handle Design on the Ergonomic Performance of Periodontal Curettes in Dental Hygienists with and without Musculoskeletal Disorders: A Pilot Clinical Study

(1) Background: Musculoskeletal disorders (MSDs), discomfort, fatigue, pain, and other acute and chronic work-related injuries are common among dental clinicians. Hand instruments constitute a primary risk factor for these conditions. The overall goal of this study was to compare in dental hygienists with healthy hands, and in those with MSDs, the effect of three different handle designs on instrumentation-related muscle work, comfort, fatigue, and quality of tactile feedback. (2) Methods: Clinicians tested three periodontal curettes: one with a novel adaptive silicone handle, another with a rigid resin handle, and the third with a rigid silicone handle. Ten hygienists-five with MSDs and five without-each scaled three typodonts using the three different curettes. Statistical analysis was performed using a General Linear Model (GLIM) and Tukey's post hoc test, and a significance level of p < 0.05 was implemented. (3) Results: On average, mean comfort and fatigue across all instruments were significantly worse in testers with MSDs, who also expended significantly more work to complete the same task. In all testers, a novel adaptive handle design was associated with significantly reduced total muscle work and post-instrumentation fatigue, as well as better comfort than conventional rigid handle designs. (4) Conclusions: An adaptive curette handle design demonstrated significantly better ergonomic outcomes than conventional rigid curette handle designs. Hygienists with MSDs expend significantly more muscle work during dental instrumentation.

A Novel Ergonomic Curette Design Reduces Dental Prophylaxis-Induced Muscle Work and Fatigue

BACKGROUND

To compare fatigue, comfort, and muscle work associated with the use of two periodontal curettes during scaling: one with a novel adaptive design, the other with a conventional non-adaptive design.

METHODS

Twelve hygienists scaled a typodont using two Universal Barnhart 5/6 curettes: (1) a prototype featuring an adaptive silicone-covered handle (Curette A), and (2) a stainless-steel curette (Curette B). Surface Electromyography (sEMG) traced muscle work. Hand positions, fatigue, comfort, pinch, and grasp strength were recorded. Paired t-tests and a repeated measures ANOVA with covariates were tested for differences. The significance level was set at p < 0.05.

RESULTS

Curette A performed significantly better in all categories. Pinch and grasp strength and fatigue were significantly reduced post-instrumentation for Curette B. Curette A required significantly less (i) total muscle work and (ii) work in individual muscles. Comfort, correct grasp, and blade adaptation were significantly better using Curette A.

CONCLUSIONS

A curette featuring a novel adaptive handle design demonstrated significantly improved ergonomic performance. Additional clinical studies are needed to solidify our understanding of the potential short- and long-term benefits of the novel curette handle design.

PRACTICAL IMPLICATIONS

A novel adaptive curette handle design that enables the clinician to adapt the instrument across the index finger may reduce musculoskeletal burden and fatigue, as well as improve comfort during periodontal instrumentation.

Evaluating the Dental Hygienists' Exposure to the Risk of Musculoskeletal Disorders

OBJECTIVES

 The aim of the study was to evaluate dental hygienists' exposure to the risk of musculoskeletal disorders (MSDs), by the worksheets compatible with the Rapid Entire Body Assessment (REBA).

MATERIALS AND METHODS

 The research included 272 dental hygienists aged 23 to 52 years from the two administrative regions of Poland.

STATISTICAL ANALYSIS

 STATISTICA 12 and Microsoft Excel were used to analyse the results. The level of significance was p<0.05. The normality of the distribution was tested with the Shapiro-Wilk test. The relationships between the variables were assessed with the χ2 test. Due to the lack of "normality" of the REBA risk distribution, the Mann-Whitney test was used to verify the hypotheses.

RESULTS

 Overall, 48.5% of the examined showed a neck flexion >20, torsion of 80.1%, and 37.5% declared the presence of both types of loads. Also, 14.3% of the examined kept a vertical position, 53.7% flexion to the torso up to 20degrees, 31.4% to 60degrees, and 2.1% to >60degrees. Further, 78.3% of people indicated that they twist the torso. Then, 7% marked the low load's arms position, 45.6% marked the range from 20 to 45degrees, and 39.7% marked the range from 45 to 90degrees. Over 55% showed additional load related to the raising or abduction of the shoulders. Overall, 43% showed a wrong position of forearms. Also, 62.9% showed wrists flexed <15° and the rest showed >15degrees. Again, 79% showed additional twisting and flexion of the wrists. Almost 75% of the examined are exposed to overloads associated with the static load. The examined are not exposed to excessive loads resulting from sudden exertion. REBA scores indicate that the negligible MSDs risk concerns 0.7% examined; low risk, 5.5%; medium risk, 33,1%; high risk, 49.3%; and very high risk, 11.4%. The correlation coeffcients analysis showed that exposure risk is strongly correlated with the overloads on the tested parts of the body in both groups.

CONCLUSION

 The levels of MSDs risk indicate that hygienists more often should be subjected to periodic check-ups in the workplace. They also need ergonomic interventions (education, preventive technique, physical activity, and improvement of the working environment) and modifications of hygienist's college programs in the field of work ergonomics can be also considered.

Wearable Motion Capture Devices for the Prevention of Work-Related Musculoskeletal Disorders in Ergonomics-An Overview of Current Applications, Challenges, and Future Opportunities

Work-related musculoskeletal disorders (WMSDs) are a major contributor to disability worldwide and substantial societal costs. The use of wearable motion capture instruments has a role in preventing WMSDs by contributing to improvements in exposure and risk assessment and potentially improved effectiveness in work technique training. Given the versatile potential for wearables, this article aims to provide an overview of their application related to the prevention of WMSDs of the trunk and upper limbs and discusses challenges for the technology to support prevention measures and future opportunities, including future research needs. The relevant literature was identified from a screening of recent systematic literature reviews and overviews, and more recent studies were identified by a literature search using the Web of Science platform. Wearable technology enables continuous measurements of multiple body segments of superior accuracy and precision compared to observational tools. The technology also enables real-time visualization of exposures, automatic analyses, and real-time feedback to the user. While miniaturization and improved usability and wearability can expand the use also to more occupational settings and increase use among occupational safety and health practitioners, several fundamental challenges remain to be resolved. The future opportunities of increased usage of wearable motion capture devices for the prevention of work-related musculoskeletal disorders may require more international collaborations for creating common standards for measurements, analyses, and exposure metrics, which can be related to epidemiologically based risk categories for work-related musculoskeletal disorders.

Pinch force generation during scaling by dental professionals: A systematic review

OBJECTIVE

The objective of this review was to examine the impact of instrument designs on pinch force generation during scaling by dental professionals.

METHODS

Three databases were utilized from September 2019 to November 2021 in addition to hand-searching specific journals and reference lists. Research articles that examined pinch force generation in dental professionals during scaling with manual instruments only were included. Bias was assessed in the individual articles.

RESULTS

Six research articles were included with sample populations that varied from 12 to 24 participants. Four articles evaluated instrument designs in relation to pinch force generation during scaling by dental professionals. Two articles evaluated the clinicians' experience levels and the impact on pinch force generation. Results of three articles revealed instruments with large diameters and low weights produced the least amount of pinch force (p < 0.05). Additionally, two articles found instruments with a round, tapered shape produced less pinch force and instrument handles made of silicone produced higher pinch strength post-scaling (p < 0.05). One study indicated instrument designs associated with modified scaling techniques may reduce thumb and index finger pinch force (p < 0.05).

CONCLUSION

The findings from this review indicate weak evidence for instrument choices to reduce pinch force during scaling. Dental professionals should consider lightweight and large diameter instruments for manual scaling. Clinicians may also want to consider round, tapered handles and instrument designs with modified scaling techniques. This systematic review further identified the need for clinical research studies with rigorous research designs that examine the ergonomic impacts of instrument designs.

Surgeons' physical workload in open surgery versus robot-assisted surgery and nonsurgical tasks

BACKGROUND

Musculoskeletal disorders (MSDs) are common among surgeons, and its prevalence varies among surgical modalities. There are conflicting results concerning the correlation between adverse work exposures and MSD prevalence in different surgical modalities. The progress of rationalization in health care may lead to job intensification for surgeons, but the literature is scarce regarding to what extent such intensification influences the physical workload in surgery. The objectives of this study were to quantify the physical workload in open surgery and compare it to that in (1) nonsurgical tasks and (2) two surgeon roles in robot-assisted surgery (RAS).

METHODS

The physical workload of 22 surgeons (12 performing open surgery and 10 RAS) was measured during surgical workdays, which includes trapezius muscle activity from electromyography, and posture and movement of the head, upper arms and trunk from inertial measurement units. The physical workload of surgeons in open surgery was compared to that in nonsurgical tasks, and to the chief and assistant surgeons in RAS, and to the corresponding proposed action levels. Mixed-effects models were used to analyze the differences.

RESULTS

Open surgery constituted more than half of a surgical workday. It was associated with more awkward postures of the head and trunk than nonsurgical tasks. It was also associated with higher trapezius muscle activity levels, less muscle rest time and a higher proportion of sustained low muscle activity than nonsurgical tasks and the two roles in RAS. The head inclination and trapezius activity in open surgery exceeded the proposed action levels.

CONCLUSIONS

The physical workload of surgeons in open surgery, which exceeded the proposed action levels, was higher than that in RAS and that in nonsurgical tasks. Demands of increased operation time may result in higher physical workload for open surgeons, which poses an increased risk of MSDs. Risk-reducing measures are, therefore, needed.

Mind the gap - development of conversion models between accelerometer- and IMU-based measurements of arm and trunk postures and movements in warehouse work

Sensor type (accelerometers only versus inertial measurement units, IMUs) and angular velocity computational method (inclination versus generalized velocity) have been shown to affect the measurements of arm and trunk movements. This study developed models for conversions between accelerometer and IMU measurements of arm and trunk inclination and between accelerometer and IMU measurements of inclination and generalized (arm) velocities. Full-workday recordings from accelerometers and IMUs of arm and trunk postures and movements from 38 warehouse workers were used to develop 4 angular (posture) and 24 angular velocity (movement) conversion models for the distributions of the data. A power function with one coefficient and one exponent was used, and it correlated well (r2 > 0.999) in all cases to the average curves comparing one measurement with another. These conversion models facilitate the comparison and merging of measurements of arm and trunk movements collected using the two sensor types and the two computational methods.

Ergonomics problems in dental profession-dentists working position

Background/Aim: Dental professionals are under higher risk of development musculoskeletal disorders. Working in unnatural position is one of the main risk factor for the development of MSDs. The aim of study was to record inclinations of the back in dentists during typically dental work. Material and Methods: In order to monitor the inclination of the body, high-performance sensor systems, triaxial digital 12-bit accelerometers LIS3LV02 (SGS-Thomson Microelectronics, USA) were installed. The inclination of the body was measured in ten dentists, while performing dental work. Results: During dental work in a sitting position, sloping back more than 20 ̊ was during 74% of the time, while during standing 62% of the time. The participants performed the dental examination sloping to the left side. During sitting, the inclination to the left side was greater than 20 ̊ during 65% of the time, while during work in the standing position it was 50%. Conclusions: An inclination of the back, more than 20 degrees is state as one of the main risk factor for the development of MSD. Inclination of the dentist's body in antero-posterior and medio-lateral direction during daily work in standing as well in sitting position was greater than 20 degrees. According to those facts dentists are under risk of developing musculoskeletal diseases during their daily working procedure. According to that ergonomics in dentistry is an area of research that needs more attention. The implementation of ergonomic principles in usual dental work leads to increased work performance, greater satisfaction, efficiency and productivity.

Ergonomics problems in dental profession-dentists working position

Background/Aim: Dental professionals are under higher risk of development musculoskeletal disorders. Working in unnatural position is one of the main risk factor for the development of MSDs. The aim of study was to record inclinations of the back in dentists during typically dental work. Material and Methods: In order to monitor the inclination of the body, high-performance sensor systems, triaxial digital 12-bit accelerometers LIS3LV02 (SGS-Thomson Microelectronics, USA) were installed. The inclination of the body was measured in ten dentists, while performing dental work. Results: During dental work in a sitting position, sloping back more than 20 ̊ was during 74% of the time, while during standing 62% of the time. The participants performed the dental examination sloping to the left side. During sitting, the inclination to the left side was greater than 20 ̊ during 65% of the time, while during work in the standing position it was 50%. Conclusions: An inclination of the back, more than 20 degrees is state as one of the main risk factor for the development of MSD. Inclination of the dentist's body in antero-posterior and medio-lateral direction during daily work in standing as well in sitting position was greater than 20 degrees. According to those facts dentists are under risk of developing musculoskeletal diseases during their daily working procedure. According to that ergonomics in dentistry is an area of research that needs more attention. The implementation of ergonomic principles in usual dental work leads to increased work performance, greater satisfaction, efficiency and productivity

Evaluating cyclist biometrics to develop urban transportation safety metrics

The transportation safety paradigm for urban transportation - particularly safety for those walking and cycling - relies on counting crashes to parameterize safety. These objective measures of safety are spatially static and reflective of past events: they can be enriched by including the human response to risk at diverse infrastructure designs. This perceived risk has been well captured qualitatively in the transportation safety literature; in the following study, we seek to develop a quantitative methodology that captures perceived risk as a continuous measure of human biometrics. Building on diverse safety-critical fields, we hypothesize that the perception of safety can be measured proactively with traveler biometrics, including eye and head movements, such that high readings of biometric indicators correlate with less safe areas. We collect biometric data from cyclists traversing an urban corridor with a protected, yet not continuously, cycle lane. By isolating and correlating peaks in cyclist biometric measures with infrastructure design, we develop a set of continuous variables - lateral head movements, gaze velocity, and off-mean gaze distance, both independently and as a vector - that allow for the evaluation of urban infrastructure based on perceived risk. The results reflect that higher biometric readings correspond to less safe (i.e., unprotected) areas, indicating that perceived risk can be measured proactively with biometric data.

Effects of Sensor Types and Angular Velocity Computational Methods in Field Measurements of Occupational Upper Arm and Trunk Postures and Movements

Accelerometer-based inclinometers have dominated kinematic measurements in previous field studies, while the use of inertial measurement units that additionally include gyroscopes is rapidly increasing. Recent laboratory studies suggest that these two sensor types and the two commonly used angular velocity computational methods may produce substantially different results. The aim of this study was, therefore, to evaluate the effects of sensor types and angular velocity computational methods on the measures of work postures and movements in a real occupational setting. Half-workday recordings of arm and trunk postures, and movements from 38 warehouse workers were compared using two sensor types: accelerometers versus accelerometers with gyroscopes-and using two angular velocity computational methods, i.e., inclination velocity versus generalized velocity. The results showed an overall small difference (<2° and value independent) for posture percentiles between the two sensor types, but substantial differences in movement percentiles both between the sensor types and between the angular computational methods. For example, the group mean of the 50th percentiles were for accelerometers: 71°/s (generalized velocity) and 33°/s (inclination velocity)-and for accelerometers with gyroscopes: 31°/s (generalized velocity) and 16°/s (inclination velocity). The significant effects of sensor types and angular computational methods on angular velocity measures in field work are important in inter-study comparisons and in comparisons to recommended threshold limit values.

Effect of standing desk use on cognitive performance and physical workload while engaged with high cognitive demand tasks

It is clear that the cognitive resources invested in standing are greater than in sitting, but six of eight previous studies suggested that there is no difference in cognitive performance. This study investigated the effects of sitting and standing workstations on the physical workload and cognitive performance under variable cognitive demand conditions. Fifteen participants visited two times for testing sitting and standing workstations, and were asked to play two difficulty levels of Tetris game for 40 min while kinematic variables, CoP regularity, CoP SD, and cognitive performances were captured every 5 min. Results revealed a more neural posture in standing than in sitting, but using the standing workstation degraded attention and executive function. The CoP SD was 7 times greater in standing, but the CoP regularity was 1/4 in sitting, denoting greater attentional investment while engaged at the standing workstation.

Improvement of Workplace Environment That Affects Motivation of Japanese Dental Hygienists

Dental hygienists are in high demand due to insufficient workforce and a lack of an effective reinstatement support system. We investigated the reasons for willingness to work by analyzing the survey results of the employment status of Japanese dental hygienists conducted by Japan Dental Hygienists’ Association. In total, we mailed 16,113 questionnaires to all members of the association (response rate 53.4%). We carried out statistical analysis to determine the specific items to improve the hygienists’ working environment. Fourteen factors of working conditions that they wish to improve were determined. Structural equation modeling showed that a path, “Reduction of work volume”, “Reduction of working hours” and “Increased number of holidays” were higher than other items. A decision analysis demonstrated that most of the respondents answered “Yes” to “Improvement in working conditions including higher salary” out of those who answered, “Strongly disagree” for “Do you feel that dental hygienist work is rewarding?”. Improving workplace environment is integral to keeping high levels of work motivation and a low turnover rate. Most of the hygienists wish for a salary raise among all the conditions. The transition from conventional work styles to non-conventional flexible working patterns is needed.

The effectiveness of ergonomics interventions in reducing upper limb work-related musculoskeletal pain and dysfunction in sonographers, surgeons and dentists: a systematic review

The aim of this systematic review was to summarise the effects of ergonomics interventions on work-related upper limb musculoskeletal pain and dysfunction, and on productivity in sonographers, surgeons and dentists. A total of 31 studies were included. All studies reported effects on upper limb pain. Nine studies reported effects on dysfunction and only two studies reported effects on productivity. Moderately strong evidence in reducing upper limb pain was found for instigation of microbreaks into long duration surgical procedures, and the use of wider, lighter handles in dental instruments. Moderate evidence was also found for use of prismatic glasses and favourable positioning in reducing upper limb pain. Weak, inconsistent or no evidence was found for all other ergonomics interventions in reducing upper limb pain and dysfunction and increasing productivity. The lack of high quality research, particularly in sonographers and in the outcome of productivity, should be addressed. Practitioner summary: This systematic review investigates the effectiveness of ergonomics interventions on upper limb pain, dysfunction and productivity in sonographers, dentists and surgeons. Instigation of microbreaks during long duration procedures and the use of wider, lighter instrument handles were most effective in reducing upper limb work-related pain. Abbreviations: ANOVA: analysis of variance; CLS: conventional laparoscopic surgery; DMAIC: define, measure, analyze, improve and control; GRADE: grading of recommendations, assessment, development and evaluations; HD: high definition; PRISMA: preferred reporting items for systematic reviews and meta-analyses; PROSPERO: The International Prospective Register of Systematic Reviews; RCT: randomised control trial; SILS: single incision laparoscopic surgery; VITOM: video telescopic operative microscope; WNSWLHD: Western New South Wales Local Health District; WMSD: work related musculoskeletal disorder.

Surgeons' posture and muscle strain during laparoscopic and robotic surgery

Background

It is assumed that conventional laparoscopy (LAP) and robotic-assisted laparoscopic surgery (RALS) differ in terms of the surgeon's comfort. This study compared muscle workload, work posture and perceived physical exertion of surgeons performing LAP or RALS.

Methods

Colorectal surgeons with experience in advanced LAP and RALS performed one of each operation. Bipolar surface electromyography (EMG) recordings were made from forearm, shoulder and neck muscles, and expressed relative to EMG maximum (%EMGmax). The static, median and peak levels of muscle activity were calculated, and an exposure variation analysis undertaken. Postural observations were carried out every 10 min, and ratings of perceived physical exertion before and after surgery were recorded.

Results

The study included 13 surgeons. Surgeons performing LAP showed higher static, median, and peak forearm muscle activity than those undertaking RALS. Muscle activity at peak level was higher during RALS than LAP. Exposure variation analysis demonstrated long-lasting periods of low-level intensity muscle activity in the shoulders for LAP, in the forearms for RALS, and in the neck for both procedures. Postural observations revealed a greater need for a change in work posture when performing LAP compared with RALS. Perceived physical exertion was no different between the surgical modalities.

Conclusion

Minimally invasive surgery requires long-term static muscle activity with a high physical workload for surgeons. RALS is less demanding on posture.

Surgeons' muscle load during robotic-assisted laparoscopy performed with a regular office chair and the preferred of two ergonomic chairs: A pilot study

Surgeons work in awkward work postures and have high precision demands - well-known risk factors for musculoskeletal pain. Robotic-assisted laparoscopy is expected to be less demanding compared to conventional laparoscopy; however, studies indicate that robotic-assisted laparoscopy is also associated with poor ergonomics and musculoskeletal pain. The ergonomic condition in the robotic console is partially dependent upon the chair provided, which often is a regular office chair. Our study quantified and compared the muscular load during robotic-assisted laparoscopy using one of two custom built ergonomic chairs and a regular office chair. The results demonstrated no differences that could be considered clinically relevant. Overall, the study showed high levels of static and mean muscular activity, increased perceived physical exertion from pre-to-post surgery, and moderate to high risk for musculoskeletal injuries measured by the Rapid Upper Limb Assessment worksheet. Authors advocate for further investigation in surgeons' ergonomics and physical work demands in robotic surgery.

A comparison of biomechanical workload between smartphone and smartwatch while sitting and standing

Increasing concerns about musculoskeletal disorders in the upper back arising from excessive daily use of the smartwatch have been widely validated by the rising prevalence of discomfort. This study explored the smartwatch as a potential ergonomic intervention over the smartphone. Fourteen healthy participants completed five tasks (application setting, calling, message typing, message checking and vocal message entry) with smartphone and smartwatch in both sitting and standing postures. The neck-shoulder kinematics and muscle activation levels were monitored to assess the effects of the tasks, devices, and postures. The results indicated greater head flexion, head rotation and shoulder abduction and greater muscle activities for smartwatch use compared to smartphone use, but the performance measure (i.e., elapsed time) was superior for smartwatch use in all tasks except message typing. Collectively, only short and simple tasks such as message checking and application setting should be conducted with the smartwatch.

Self-recordings of upper arm elevation during cleaning - comparison between analyses using a simplified reference posture and a standard reference posture

BACKGROUND

To reduce ergonomic risk factors in terms of awkward and constrained postures and high velocities, it is important to perform adequate risk assessments. Technical methods provide objective measures of physical workload. These methods have so far mainly been used by researchers. However, if written instructions how to apply the sensors and how to adopt the reference posture are provided, together with triaxial accelerometers, it may be possible for employees to record their own physical workload. The exposure in terms of e.g. upper arm elevations could then easily be assessed for all workers in a workplace. The main aims of this study were: 1) to compare analyses for self-recording of upper arm elevation during work using a simplified reference posture versus using a standard reference posture, and 2) to compare the two reference postures.

METHODS

Twenty-eight cleaners attached an accelerometer to their dominant upper arm and adopted a simplified reference according to a written instruction. They were thereafter instructed by a researcher to adopt a standard reference. Upper arm elevations were recorded for 2 or 3 days. Each recording was analysed twice; relative to the simplified reference posture and relative to the standard reference posture. The group means of the differences in recorded upper arm elevations between simplified and standard reference analyses were assessed using Wilcoxon signed ranks test. Furthermore, we calculated the group mean of the differences between the simplified reference posture and the standard reference posture.

RESULTS

For arm elevation during work (50th percentile), the group mean of the differences between the two analyses was 0.2° (range -7 - 10°). The group mean of the differences between the two references was 9° (range 1 - 21°). The subjects were able to follow the instructions in the protocol and performed self-recording of upper arm elevation and velocity.

CONCLUSIONS

The small difference between the two analyses indicates that recordings performed by employees themselves are comparable, on a group level, with those performed by researchers. Self-recordings in combination with action levels would provide employers with a method for risk assessment as a solid basis for prevention of work-related musculoskeletal disorders.

Effect of neck posture on cervicothoracic loads in overhead crane operators

Awkward neck postures are commonly documented to be associated with an increased risk of neck disorders. This study intended to continuously monitor and evaluate neck postures and to estimate the cervicothoracic loads among overhead crane operators during work time. Neck postures were measured among 40 randomly selected operators by an inclinometer during 2 h of work time. To determine the tasks and adapt the posture recordings to each of their corresponding tasks, direct observation was conducted concurrently. The median neck flexion and lateral bend angles were 28.23° and 11.30°, respectively. The mean compression and shear loads on the neck ranged from 75.22 to 113.14 N and from 9.50 to 41.11 N, respectively. The results indicated substantial levels of exposure to awkward and extreme neck postures among the operators. The nature of the operators' work and the visual requirements of some tasks will increase the mechanical loads on the neck.

Assessment of risk factors and preventive measures and their relations to work-related musculoskeletal pain among dentists

BACKGROUND

Dentists have a high prevalence of musculoskeletal (MS) pain, which is the most common symptom associated with work-related musculoskeletal disorders (WMSDs). To overcome this problem, identification of the risk factors and preventive measures for MS pain are of paramount importance to dentists in order to improve their quality of life and work.

OBJECTIVES

The aims of this study were to recognize the risk factors for MS pain and their impact on dental work, as well as to identify preventive measures of MS pain among dentists.

METHODS

Self-reporting questionnaire consisting of 78 questions was exclusively developed for the study and sent to 500 working active dentists in Serbia.

RESULTS

Response rate was 71.2% (356 dentists). The prevalence of MS pain was 82.6% among dentists. The main risk factors for MS pain were advanced age, female dentists, presence of chronic diseases, long working hours, and high frequency of treated patients. The most effective preventive measures in preventing MS pain were massage treatments and physical activities. Followed by use of ergonomically designed equipment, correct and dynamic working positions, and an adequate workflow organization.

CONCLUSION

The risk factors for MS pain and their impact on dental work should widely be disseminated among dentists. Importantly, proper implementation in everyday life of adequate preventive measures is essential for preventing MS pain and development of WMSDs.

Musculoskeletal symptoms of the neck and shoulder among dental practitioners

OBJECTIVES

Musculoskeletal symptoms of the neck and shoulder represent a condition whose basic characteristic is pain. These conditions are very often present in dental health professionals. The aim of the paper was to determine presence of discomforts in areas of head, neck, shoulders, upper back and upper limbs at health professionals in area of dentistry, as well as discomfort localisation and methods of treatment.

METHODS

The research included 45 health professionals (dentists, dental assistants and dental technicians) employed at Dental Clinic of Vojvodina. The information was collected via questionnaire for analysis musculoskeletal disorders.

RESULTS

Most of the dentists (75.9%) and the dental assistants (90.9%) as well as nearly half of the dental technicians (40%) experience discomforts in area of the neck, which are occasional, present in all three working positions and this discomforts are a little more frequent at women. The present musculoskeletal disorders are followed by headache, whose presence is statistically more significant compared to the other symptoms. The headache is usually located in the occipital part, it occurs individually or joined with other symptoms. Due to said discomforts the examinees in 59.4% of the cases don't contact the doctor. Medical therapy prevails in opposition to physical therapy.

CONCLUSION

The discomforts deriving from the cervical part of the spine are present at great percentage of our examinees. Considering the fact that the said discomforts affect performing both professional and everyday activities, its prevention is necessary in order to avoid the consequences they carry.

Physical workload and musculoskeletal disorders in back, shoulders and neck among welders

This study aimed to determine the effect of the physical workload on the back, neck and shoulders of welders. The prevalence of musculoskeletal symptoms was assessed using the Nordic questionnaire among 15 welders. The physical workload of the neck, back and upper arms was then measured by means of inclinometry as the welders were working. The results revealed that the highest prevalence of musculoskeletal disorders during the previous 12 months was in the lower back and shoulders. The median trunk and neck flexion were significantly associated with back and neck pain in welders with symptoms during the past year (p < 0.05). Physical exposure in welders with pain was characterized by significantly more awkward postures and percentage of time spent with the trunk and neck flexed more than 20°. The nature of their work and the design of their workstations may be causes of the symptoms they experienced during work.

Workplace health in dental care - a salutogenic approach

OBJECTIVE

The purpose was to explore self-reported psychosocial health and work environments among different dental occupations and workplaces from a salutogenic perspective. A further purpose was to analyse possible associations between three salutogenic measurements: The Sense of Coherence questionnaire (SOC), the Salutogenic Health Indicator Scale (SHIS) and the Work Experience Measurement Scale (WEMS).

METHODS

Employees in the Public Dental Service in a Swedish county council (n = 486) were invited to respond to a self-reported web survey including demographics, work-related factors, the SOC, the SHIS and the WEMS.

RESULTS

This study showed positive associations between employee characteristics and self-reported overall psychosocial health as well as experienced work environment. Autonomy was reported more among men than women (P < 0.000) and to a higher degree by dentists and dental hygienists than dental nurses (P < 0.000). Meaningfulness, happiness, job satisfaction, autonomy and positive to reorganization were reported by personnels aged less than 40 years (P ≤ 0.047). Clinical coordinators reported significant better health (SOC, SHIS) and experienced more autonomy, better management and more positive to reorganization than other dental professions. Dental hygienists and nurses experienced less time pressure than dentists (P ≤ 0.007). Better health and positive work experiences were also seen in smaller clinics (P ≤ 0.29).

CONCLUSION

Dental professionals reported a high degree of overall psychosocial health as well as a positive work experience. Some variations could be seen between employee characteristics such as gender, years in dental care, professionals, managing position and workplace size. Identify resources and processes at each workplace are important and should be included in the employee's/employers dialogue.

Comparing two methods to record maximal voluntary contractions and different electrode positions in recordings of forearm extensor muscle activity: Refining risk assessments for work-related wrist disorders

BACKGROUND:

Wrist disorders are common in force demanding industrial repetitive work. Visual assessment of force demands have a low reliability, instead surface electromyography (EMG) may be used as part of a risk assessment for work-related wrist disorders. For normalization of EMG recordings, a power grip (hand grip) is often used as maximal voluntary contraction (MVC) of the forearm extensor muscles. However, the test-retest reproducibility is poor and EMG amplitudes exceeding 100% have occasionally been recorded during work. An alternative MVC is resisted wrist extension, which may be more reliable.

OBJECTIVE:

To compare hand grip and resisted wrist extension MVCs, in terms of amplitude and reproducibility, and to examine the effect of electrode positioning.

METHODS:

Twelve subjects participated. EMG from right forearm extensors, from four electrode pairs, was recorded during MVCs, on three separate occasions.

RESULTS:

The group mean EMG amplitudes for resisted wrist extension were 1.2–1.7 times greater than those for hand grip. Resisted wrist extension showed better reproducibility than hand grip.

CONCLUSIONS:

The results indicate that the use of resisted wrist extension is a more accurate measurement of maximal effort of wrist extensor contractions than using hand grip and should increase the precision in EMG recordings from forearm extensor muscles, which in turn will increase the quality of risk assessments that are based on these.

Musculoskeletal pain symptoms among allied health professions' students: Prevalence rates and associated factors

BACKGROUND

Very few articles, comprehensively, investigated musculoskeletal pain symptoms (MPS) among wide variety of allied health professions (AHP) students.

OBJECTIVES

This study aimed to investigate the prevalence of MPS and their associated factors among different AHP majors' students.

METHOD

A cross-sectional design was conducted. A sample of AHP students from nine majors (n= 838, Mean age = 21.3 years) completed a validated structured self-administrated questionnaires including Nordic Musculoskeletal Questionnaire, Depression Anxiety Stress Scale (DASS 21), and specific questions regarding demographics and life style. MPS prevalence rate were compared between males and females and between majors. Logistic regression was conducted to identify predictors of MPS.

RESULTS

MPS in neck, lower back, and shoulder 12-month were the most prevalent (67.1%, and 61.4%, 58.8% respectively). MPS prevalence was significantly higher in females and statistically different among majors. MPS were significantly associated with increased clinical training load, mental stress symptoms, and smartphone average use time.

CONCLUSIONS

MPS in AHP students are prevalent and statistically higher among females. Students are advised to adhere to different conservative precautions and follow prevention programs. Future studies are needed to assess actual mechanisms causing MPS among AHP students and designing effective prevention programs specific to AHP students.

Investigation of musculoskeletal discomfort, work postures, and muscle activation among practicing tattoo artists

Tattoo artists are an understudied worker population with respect to investigation of work-related musculoskeletal (MSK) discomfort and associated risk factors. Results from one discomfort survey has been published; no analysis of worker biomechanics has been published. As such, a study was conducted to begin exposure assessment of tattoo artists to work factors that could result in MSK discomfort. Consistent with the prior survey, the current study showed an elevated prevalence of MSK discomfort. Twelve month discomfort prevalence exceeded 50% in the neck, shoulders, hands/wrists, and upper and lower back (range: 53-94%). Seventy-one percent of postures evaluated during 16 h of observation had total RULA scores of 5, 6, or 7 (investigation and changes are required soon or immediately). Static muscle activity levels in the left, right, or both upper trapezius muscles in each study participant exceeded the 2-5% MVE limit recommended in the literature. Intervention concepts are also discussed.

The biomechanical demands of manual scaling on the shoulders & neck of dental hygienists

The purpose of this study was to evaluate the postural and muscular demands placed on the shoulders and neck of dental hygienists when performing a simulated manual scaling task. Nineteen healthy female dental hygienists performed 30-min of simulated manual scaling on a manikin head in a laboratory setting. Surface electromyography was used to monitor muscle activity from several neck and shoulder muscles, and neck and arm elevation kinematics were evaluated using motion capture. The simulated scaling task resulted in a large range of neck and arm elevation angles and excessive low-level muscular demands in the neck extensor and scapular stabilising muscles. The physical demands varied depending on the working position of the hygienists relative to the manikin head. These findings are valuable in guiding future ergonomics interventions aimed at reducing the physical exposures of dental hygiene work. Practitioner Summary: Given that this study evaluates the physical demands of manual scaling, a procedure that is fundamental to dental hygiene work, the findings are valuable to identify ergonomics interventions to reduce the prevalence of work-related injuries, disability and the potential for early retirement among this occupational group.

Attitudes and barriers to providing dietary advice: perceptions of dental hygienists and oral health therapists

OBJECTIVES

Effective dietary counselling in a dental setting can significantly reduce the risk of oral disease. However, studies suggest that dental professionals are not instigating dietary advice on a regular basis, and there is a lack of current information of the barriers experienced that limit the delivery of dietary advice. The aim of this study was to investigate the current attitudes and practice behaviours of dental hygienists and oral health therapists in NSW, Australia, regarding dietary advice, and identify the barriers that limit its delivery.

METHODS

A convenience sample of dental hygienists and oral health therapists were surveyed using a mail-out questionnaire. The questionnaire investigated the demographic data of participants, the attitudes and practice behaviours of participants, the perceived barriers and current dietary resources accessed by participants.

RESULTS

Of 987 dental hygienists and oral health therapists, 426 participants responded. The study results suggest that many dental hygienists and oral health therapists have positive beliefs regarding the importance of dietary counselling. However, there are a multitude of barriers preventing the delivery of dietary advice; these include time, patient compliance, patient knowledge of nutrition topics, personal counselling skills and practitioners' knowledge of nutrition.

CONCLUSION

Whilst dental hygienists and oral health therapists recognize the importance of diet and have positive attitudes towards providing dietary advice to patients, this study identified many barriers preventing implementation in practice. This information may be used to develop targeted strategies aimed at overcoming these barriers and improving behaviours.

Opting to wear prismatic spectacles was associated with reduced neck pain in dental personnel: a longitudinal cohort study

Background

The aim of this study was to investigate effects on perceived exertion, work ability self-reported neck pain and clinically diagnosed conditions in the neck, of an intervention with prismatic spectacles among dental personnel.

Methods

In this cohort study a baseline questionnaire including questions about frequency of neck pain, perceived exertion during work and background information was distributed to dental personnel in municipal dental care units. In connection, personnel from 78 out of 110 dental care units underwent a clinical neck examination and rated their perceived work ability with the single-item question from the Work Ability Index. The study population consisted of 564 participants; 366 in the questionnaire group, 321 in the examination group, whereof 123 participated in both assessments. In total 371 belonged to the intervention group and received individually adjusted prismatic spectacles after the baseline assessments (inclusion based on self-selection) and 193 belonged to the reference group. At the 12-month follow-up the clinical examination was repeated and the same questionnaire with additional questions was completed. Fisher’s exact test or the Mann–Whitney U test was used to assess differences between the intervention group and the reference group at baseline. Differences at follow up between the two groups were assessed by means of Linear-by Linear association test for trends.

Results

A significant decrease in neck pain (p = 0.047), clinical diagnoses in the neck (p = 0.025), and perceived exertion (p = 0.003) was observed at follow up for the intervention group compared to the reference group. Moreover, for the intervention group a significantly improved self-rated work ability (p = 0.040) was reported. Finally, opting to wear prismatic spectacles during dental work appeared to have a preventive effect on neck pain.

Conclusions

Dental personnel opting to wear prismatic spectacles reduced their neck pain significantly more at follow up compared with the reference group. These results are worthwhile testing in a randomised design. The practical implication of this study is that recommendations regarding ergonomics for dental professionals may include the use of prismatic glasses, both as primary and secondary prevention of work-related neck pain. Such glasses should also be tested in other working situations where the work tasks include high visual demands in sustained awkward neck postures.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1145-1) contains supplementary material, which is available to authorized users.

Intraoperative workload in robotic surgery assessed by wearable motion tracking sensors and questionnaires

BACKGROUND

The introduction of robotic technology has revolutionized radical prostatectomy surgery. However, the potential benefits of robotic techniques may have trade-offs in increased mental demand for the surgeon and the physical demand for the assisting surgeon. This study employed an innovative motion tracking tool along with validated workload questionnaire to assess the ergonomics and workload for both assisting and console surgeons intraoperatively.

METHODS

Fifteen RARP cases were collected in this study. Cases were performed by 10 different participants, six primarily performed console tasks and four primarily performed assisting tasks. Participants had a median 12 (min-3, max-25) years of surgical experience. Both console and assisting surgeons performed robotic prostatectomy cases while wearing inertial measurement units (IMUs) that continuously track neck, shoulder, and torso motion without interfering with the sterile environment. Postoperatively, participants completed a workload questionnaire (SURG-TLX) and a body part discomfort questionnaire.

RESULTS

Twenty-six questionnaires were completed from 13 assisting and 13 console surgeons over the 15 cases. Postoperative pain was reported highest for the right shoulder and neck. Mental demands were 41 % higher for surgeons at the console than assisting (p < 0.05), while physical demands were not significantly different. Assisting surgeons worked in demanding neck postures for 58 % of the procedure compared to 24 % for the console surgeon (p < 0.01). Surgeons at the console were primarily static and showed 2-5 times fewer movements than assisting surgeons (p < 0.01).

CONCLUSIONS

Postures were more ergonomic during console tasks than when assisting by the bedside; however, the console may constrain postures leading to static loads that have been associated with musculoskeletal symptoms for the neck, torso, and shoulders. The IMU sensors were effective at quantifying ergonomics in robotic prostatectomies, and these methods and findings have broad applications to other robotic procedures.

Exposure-response relationships for work-related neck and shoulder musculoskeletal disorders--Analyses of pooled uniform data sets

There is a lack of quantitative data regarding exposure-response relationships between occupational risk factors and musculoskeletal disorders in the neck and shoulders. We explored such relationships in pooled data from a series of our cross-sectional studies. We recorded the prevalence of complaints/discomfort (Nordic Questionnaire) and diagnoses (physical examination) in 33 groups (24 female and 9 male) within which the workers had similar work tasks (3141 workers, of which 817 were males). In representative sub-groups, we recorded postures and velocities of the head (N = 299) and right upper arm (inclinometry; N = 306), right wrist postures and velocities (electrogoniometry; N = 499), and muscular activity (electromyography) in the right trapezius muscle (N = 431) and forearm extensors (N = 206). We also assessed the psychosocial work environment (Job Content Questionnaire). Uni- and multivariate linear meta-regression analysis revealed several statistically significant group-wise associations. Neck disorders were associated with head inclination, upper arm elevation, muscle activity of the trapezius and forearm extensors and wrist posture and angular velocity. Right-side shoulder disorders were associated with head and upper arm velocity, activity in the trapezius and forearm extensor muscles and wrist posture and angular velocity. The psychosocial work environment (low job control, job strain and isostrain) was also associated with disorders. Women exhibited a higher prevalence of neck and shoulder complaints and tension neck syndrome than men, when adjusting for postures, velocities, muscular activity or psychosocial exposure. In conclusion, the analyses established quantitative exposure-response relationships between neck and shoulder disorders and objective measures of the physical workload on the arm. Such information can be used for risk assessment in different occupations/work tasks, to establish quantitative exposure limits, and for the evaluation of preventive measures.

Working position influences the biomechanical demands on the lower back during dental hygiene

This investigation monitored the biomechanical demands on the lower back during simulated dental hygiene work. A total of 19 female, registered dental hygienists performed 30 continuous minutes of manual scaling (plaque removal) of a manikin's teeth while seated. We monitored the working location and orientation of the dental hygienists, with respect to the manikin, along with their spine kinematics, spine extensor muscle activities and seat pressure, throughout the 30 min. A clock representation was used to express the working location. The location significantly influenced the dental hygienists' pelvic orientation with respect to the manikin, spine posture, erector muscle activity and pressure distribution. Findings from this study suggest that the prevalence of lower back pain amongst dental hygienists may be directly related to low-level tonic activity of the spine's extensor musculature, and the combined flexed and axially rotated spine postures. Practitioner Summary: Low back pain (LBP) is prevalent in dental hygienists, yet occupational demand on the low back has not been investigated. Posture, muscle activity and seat pressure were monitored. Combined spine rotation and flexion, and tonic activity of the extensor musculature may be related to LBP in dental hygienists.

Prevalence of musculoskeletal symptoms among garment workers in Kandal province, Cambodia

OBJECTIVES

The main objectives of this cross-sectional descriptive study were to identify the prevalence of musculoskeletal symptoms and workstation biomechanical risk levels for garment workers in Kandal Province, Cambodia.

METHODS

This cross-sectional descriptive study used multistage sampling techniques to select 714 workers from three garment factories among 22 medium-size factories (250-1,000 workers). Face-to-face interviews and direct observation using the rapid upper limb assessment scale (RULA) were used to collect data.

RESULTS

The response rate was 98.3% (702/714), and the majority (89.3%) of the respondents were female. Ninety-two percent (95% CI=90.0-94.0) of the workers reported musculoskeletal symptoms in at least one body region in the previous 12 months and 89.0% (95% CI=86.7-91.3) of the workers reported such symptoms in the past seven-day period. The neck, shoulder, and lower back were the most affected body regions. In addition, the RULA data showed that 81.2% of the workers' postures were rated as action level 3, indicating that investigation and change were required soon, and that 7.5% their postures were rated as action level 4, indicating that investigation and change were required immediately.

CONCLUSIONS

Cambodian garment workers reported a high prevalence of musculoskeletal symptoms in upper body regions, and their workplaces were rated as high risk ergonomically.

The relationship between physical load and musculoskeletal complaints among Brazilian dentists

The aim of the present study was to assess the relationship between physical load and musculoskeletal complaints in dentistry and to analyze the prevalence and severity of such complaints in nine anatomical regions using a cross-sectional study of 387 dentists from Natal, Brazil. The highest prevalence of complaints was related to the lower back (58.4%) and the lowest prevalence was found in the elbow (10.3%). In general, symptoms were classified as mild because they did not cause absence due to illness. Pain complaints were associated with the following characteristics: awkward posture at work; prolonged standing or sitting; strenuous position of the upper limbs; excessive tightening of the hands during clinical treatment; and the use of vibrating tools. The results of the present study suggest a high prevalence of musculoskeletal complaints in dentists that are significantly associated with variables related to their physical workload.

Self-reported occupational health problems among Libyan dentists

OBJECTIVES

To investigate the prevalence of the most common occupation-related health problems as well as factors associated with their incidence among dental practitioners.

MATERIALS AND METHODS

A cross-sectional, questionnaire-based survey of Libyan dental practitioners. Participants provided information regarding their experience of occupationally related problems they encountered over the past 12 months which included inquiries about musculoskeletal pain, percutaneous injuries, allergy, eye and sight problems, and hearing problems.

RESULTS

Musculoskeletal problems were the most frequently reported (48.2%), followed by percutaneous injuries (35%), eye problems (22%), allergy (11%) and hearing problems (7.6%). Musculoskeletal problems were significantly higher among dentists who work in private sector, full timer as well as those who prefer to work in a sitting position (p=0.021, 0.027 and 0.008, respectively). Practitioners with less than 5 years in service reported significantly higher percentage of percutaneous injuries (p=0.027) than their senior counterparts, whereas practitioners who spent more than 10 years in service were more likely to suffer from visual disturbances (p=0.033).

CONCLUSION

The findings of this study indicate that musculoskeletal problems and percutaneous injuries are the most commonly reported occupational health problems among dentists, whereas allergic reactions and hearing problems are the least reported ones.

CLINICAL SIGNIFICANCE

Dentists should use alternate working positions to minimise musculoskeletal problems and adopt more effective strategies to prevent percutaneous injuries particularly among novices.

Trapezius muscle load, heart rate and time pressure during day and night shift in Swiss and Japanese nurses

The aim of the present study was to analyze the activity of the trapezius muscle, the heart rate and the time pressure of Swiss and Japanese nurses during day and night shifts. The parameters were measured during a day and a night shift of 17 Swiss and 22 Japanese nurses. The observed rest time of the trapezius muscle was longer for Swiss than for Japanese nurses during both shifts. The 10th and the 50th percentile of the trapezius muscle activity showed a different effect for Swiss than for Japanese nurses. It was higher during the day shift of Swiss nurses and higher during the night shift of Japanese nurses. Heart rate was higher for both Swiss and Japanese nurses during the day. The time pressure was significantly higher for Japanese than for Swiss nurses. Over the duration of the shifts, time pressure increased for Japanese nurses and slightly decreased for those from Switzerland. Considering trapezius muscle activity and time pressure, the nursing profession was more burdening for the examined Japanese nurses than for Swiss nurses. In particular, the night shift for Japanese nurses was characterized by a high trapezius muscle activity and only few rest times for the trapezius muscle.

Approach of industrial physical therapy to assessment of the musculoskeletal system and ergonomic risk factors of the dental hygienist

This study aimed to provide fundamental data to be utilized in preventing and treating musculoskeletal disorders and analyzing working postures commonly used during periodontal treatment. [Subjects] The subjects were three dental hygienists with work experience in dental clinics for more than 10 years. [Methods] For the analysis of working postures, we simulated the work posture of dental hygienists during the scaling procedures and oral radiographic imaging tasks. The subjects were recorded on video to precisely observe them while they were working. The captured working postures were assessed and analyzed using ergonomic assessment methods, the Rapid Entire Body Assessment, Rapid Upper Limb Assessment, and Strain index. [Results] No differences were exhibited in the intensities of manual scaling and ultrasonic scaling. Commonly, the shoulders and waist were found to be the most overburdened. According to the strain index, manual scaling and ultrasonic scaling working postures were identified to be most dangerous. [Conclusion] The work postures of dental hygienists during scaling are postures that are highly likely to generate work-related musculoskeletal disorders. Therefore, the development of therapeutic exercise programs easily performable in the workplace and daily life is thought to be crucial to prevent work-related musculoskeletal disorders.

Exposure-response relationships in work-related musculoskeletal disorders in elbows and hands - A synthesis of group-level data on exposure and response obtained using uniform methods of data collection

There is a serious lack of quantitative data regarding exposure-response relationships between occupational risk factors and musculoskeletal elbow and hand disorders. This paper explores such relationships in group-level data from our earlier cross-sectional studies. Prevalence of complaints (Nordic Questionnaire) and diagnoses (physical examination) were recorded in 19 groups of female workers (1891 individuals), and 8 groups of male workers (761 individuals), with highly similar work tasks within each group. Linear regression was performed on the group means of wrist postures and angular velocity (obtained by electrogoniometers), as well as muscular load (obtained using electromyography), recorded in representative sub-samples, and psychosocial exposure (Job Content Questionnaire). To tackle within-group variations in physical exposure, sensitivity analyses were performed by bootstrapping simulations, rendering confidence intervals. The sex-adjusted slope of the regression line (β) for wrist angular velocity vs. complaints during the past 7 days was 0.6%/(°/s), (95% CI 0.3-0.9), and for carpal tunnel syndrome (CTS) 0.2%/(°/s), (0.1-0.3). For palmar flexion, p50, β over the past 7 days was 0.8%/° (0.4-1.2); for CTS 0.3%/° (0.1-0.5); β for muscular activity p90: 0.9%/%MVE (0.3-1.6), and 0.3%/%MVE (-0.03-0.6) respectively and finally β for muscular rest: -1.2%/%time (-2.4-0.03) and -0.5%/%time (-0.9 to -0.01). Relationships were also demonstrated for low job control, job strain and isostrain. Women exhibited a higher prevalence of complaints than men. In conclusion, we have established quantitative exposure-response relationships between physical work load and elbow/hand disorders. Wrist angular velocity was the most consistent risk factor.

Rationalisation in public dental care--impact on clinical work tasks and mechanical exposure for dentists--a prospective study

Swedish dentistry has been exposed to frequent rationalisation initiatives during the last half century. Previous research has shown that rationalisation often results in increased risk of developing work-related musculoskeletal disorders, thus reducing sustainability in the production system. In this prospective study, we assessed mechanical exposures among Swedish dentists in relation to specific rationalisations of clinical dental work during a six-year period. Body postures and movements of 12 dentists were assessed by inclinometry synchronised to video recordings of their work. No rationalisation effects could be shown in terms of a reduction in non-value-adding work ('waste'), and at job level, no major differences in mechanical exposure could be shown between baseline and follow-up.

CONCLUSION

The present rationalisation measures in dentistry do not seem to result in rationalisation at job level, but may potentially be more successful at the overall dental system level.

PRACTITIONER SUMMARY

In contrast to many previous investigations of the mechanical exposure implications of rationalisation, the present rationalisation measures did not increase the level of risk for dentists. It is highlighted that all occupations involved in the production system should be investigated to assess production system sustainability.