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Background & Aims of the Study: Improper posture of dentists causes cumulative pressure on their body and ultimately leads to occupational injuries. Despite the existence of numerous studies performed on musculoskeletal pain, complaints around this disease are still widespread in the dentistry profession. This study was aimed at the precise identification of individual and occupational risk factors for musculoskeletal pain among dentists working in Qom, Iran, in 2018. Materials and Methods: This cross-sectional study was conducted on 51 dentists with at least one year of work experience. In this study, the occupational sitting activities were taken into account. In order to evaluate the ergonomics status of such activities, Branson’s Posture Assessment Instrument (BPAI) was used. The data were collected using a researcher-made demographic form and body map questionnaire. Statistical analysis of data was performed in SPSS software (Version 22) by Mann-Whitney U test, Kruskal-Wallis H test, and Spearman’s correlation coefficient. Results: Based on the results of the study, 84.3% (n=43) of the dentists had pain in at least one or more parts of their musculoskeletal system. The most commonly affected areas were the neck (72.7%) and shoulder (54.5%). In addition, 21.6% and 80.4% of postures were at acceptable and compromised levels, respectively. It was revealed that posture had a significant relationship with work experience and the amount of rest breaks (P

Manual materials handling (MMH) devices like jigs and fixtures are required for transporting or positioning materials in large-scale operations. An MMH device was designed to feed cassava mash into fry pan during batch gari-frying. Flow is facilitated through the tapered outlet of a 40 kg-capacity hopper while lifting is achieved by turning a triple-start screwed shaft handle, housed in a u-steel channel framework with wide rigid base that can support holding content in position without buckling. Feeding is done until the content is exhausted ready for reloading. It can deliver more than 160 kg/hr depending on the fry pan capacity and working rate. The worker avoids stretching, bending and twisting the trunk or the neck, or move round more frequently for reloading, thus overcoming the stated ergonomic risk factors and slowness of the work process. The device is also adaptable to other tasks requiring similar feeding mechanism.

[Purpose] The aim of this study was to analyze, through ergonomic analyses, those motions most used by radiological technologists that can cause musculoskeletal disorders. [Subjects and Methods] The subjects were 7 radiological technologists with work experience in hospitals for more than 5 years. For the analysis of working postures, we simulated the work posture of radiological technologists when moving patients, when pushing or pulling an apparatus, when conducting ultrasonography, and when handling a mouse for MRI were analyzed. [Results] In this study, the burdens on the radiological technologists’ waists were shown to be high when they were moving patients for a CT scan. During mouse handling for an MRI scan, large burdens were imposed on the neck. In the case of ultrasonography working postures, larger burdens on the leg and neck were found when the patient’s examination sites were located further away. The assessment of working postures when pushing a portable radiation apparatus showed that burdens on the musculoskeletal system increased as the weight of the apparatus increased. [Conclusion] The musculoskeletal disorders of radiological technologists occur in various regions of their bodies but occur most frequently in the shoulder and the lumbar region. Therefore, hospitals need to be educated regarding the concept of musculoskeletal disorders.

Objectives To investigate the relation between manipulative dexterity and vibration exposure, ergonomic risk factors, and upper limb disorders in a group of workers exposed to hand-transmitted vibration (HTV). Methods Manipulative dexterity was investigated on 115 HTV workers (82 forestry workers and 33 stone workers) and 64 control men over 1-year follow-up period. The Purdue pegboard method was used to test manipulative dexterity which was scored for the dominant hand, nondominant hand, and both hands. Information about individual, work and health history was obtained by means of a standardised questionnaire. Vibration exposure was assessed in terms of tool vibration magnitudes, daily and total exposure duration, and cumulative vibration dose. Results On the cross-sectional investigation, Purdue pegboard scores were significantly lower in the HTV workers than in the controls (0.001 \ P \ 0.05). Over 1-year follow-up period, Purdue pegboard scores were found to be inversely related to age, smoking and use of vibratory tools (0.001 \ P \ 0.05). Moreover, deterioration of some measures of manipulative dexterity was significantly associated with sensorineural and vascular symptoms in the fingers of the HTV workers. Randomintercept linear regression analysis showed that Purdue pegboard scores decreased with the increase of vibration exposure. The reduction of assembly score (i.e. number of pins, collars, and washers assembled in a 60-s period) was significantly associated with the increase in vibration exposure and ergonomic stress (neck-upper arm posture, hand-intensive work, and total ergonomic score). Purdue pegboard scores tended to improve over the follow-up period in both the controls and the HTV workers, suggesting a possible learning effect over time. Conclusion The findings of this longitudinal study suggest an association between deterioration of manipulative dexterity and neurovascular symptoms in the fingers of HTV workers. There was evidence for a significant relation between loss of precise manipulation and exposures to hand-transmitted vibration and ergonomic risk factors.

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.

An epidemiologic and clinical study of neck and upper limb musculoskeletal disorders was carried out on 65 vibration-exposed forestry operators using chain-saws and 31 comparable control subjects (maintenance workers) performing manual activity and not exposed to vibration. Upper limb function was evaluated by measuring finger and wrist circumference size, maximal hand grip strength and range of motion manoeuvres in both the controls and the exposed workers. Vibration from two chain-saws was measured, and vibration exposure for each forestry worker was assessed in terms of 4 h energy-equivalent frequency-weighted acceleration according to ISO 5349. Job analysis indicated a slight excess risk of upper extremity cumulative trauma disorders (CTDs) in the forestry operators compared with the control workers. After adjustment for age and body constitution, significantly higher prevalence rates of persistent upper limb pain, muscle-tendon syndromes and carpal tunnel syndrome were observed among the forestry workers than among the controls. In the forestry operators, the occurrence of upper limb musculoskeletal disorders increased with increasing vibration exposure. Upper limb function was found to be impaired in the forestry workers compared with the controls. Vibration exposure was significantly related to increased finger circumference size, diminished muscle force and reduced joint function. Even though it is difficult to establish the relative importance of vibration and ergonomic factors in the aetiology of CTDs, nevertheless the results of this study indicate that musculoskeletal impairment to the upper limbs was more severe in the forestry operators than in the controls who did solely manual work. This finding and the observed dose-effect relationships suggest that vibration stress is an important contributor to the development of musculoskeletal disorders in workers using hand-held vibrating tools.

The occurrence of several types of low back pain (LBP) was investigated by a standardized questionnaire in a group of 219 port machinery operators exposed to whole-body vibration (WBV) and postural load and in a control group of 85 maintenance workers employed at the same transport company. The group of port machinery operators included 85 straddle carrier drivers, 88 fork-lift truck drivers, and 46 crane operators. The vector sum of the frequency-weighted r.m.s. acceleration of vibration measured on the seatpan of port vehicles and machines averaged 0·90 m/s 2 for fork-lift trucks, 0·48 m/s 2 for straddle carriers, 0·53 m/s 2 for mobile cranes, and 0·22 m/s 2 for overhead cranes. The 12-month prevalence of low back symptoms (LBP, sciatic pain, treated LBP, sick leave due to LBP) was significantly greater in the fork-lift truck drivers than in the controls and the other two groups of port machinery operators. After adjusting for potential confounders, the prevalence of low back symptoms was found to increase with the increase of WBV exposure expressed as duration of exposure (driving years), equivalent vibration magnitude (m/s 2 ), or cumulative vibration exposure (yr m 2 /s 4 ). An excess risk for lumbar disc herniation was observed in the port machinery operators with prolonged driving experience. In both the controls and the port machinery operators, low back complaints were strongly associated with perceived postural load assessed in terms of frequency and/or duration of awkward postures at work. Multivariate analysis showed that vibration exposure and postural load were independent predictors of LBP. Even though the cross-sectional design of the present study does not permit firm conclusions on the relationship between WBV exposure and low back disorders, the findings of this investigation provide additional epidemiological evidence that seated WBV exposure combined with non-neutral trunk postures, as while driving, is associated with an increased risk of long-term adverse health effects on the lower back.

The occurrence of low-back pain (LBP) was investigated in a population of 1155 tractor drivers exposed to whole-body vibration (WBV) and postural stress (response rate 91.2%) and in a control group of 220 office workers (response rate 92.2%). The subjects were questioned about several types of low-back symptom (LBP, sciatic pain, acute LBP, transient and chronic LBP) and various work- and individual-related risk factors, by using a standardized questionnaire. Vibration measurements were performed on a representative sample of the vehicles driven by the tractor drivers in the last ten years. Vibration magnitude and duration of exposure were used to calculate a vibration dose for each tractor driver. Perceived postural load was assessed in terms of frequency and/or duration of awkward postures at work. The prevalence of LBP was found to be greater in the tractor drivers than in the controls. After controlling for potential confounders by logistic modelling, low-back disorders were found to be significantly associated with both vibration dose and postural load. Back accidents and age were also significant predictors for LBP. Quantitative regression analysis indicated that vibration exposure and postural load were independent contributors to the increased risk for LBP according to a multiplicative model. The exposure levels for WBV recently recommended by a proposal of European Directive on physical agents seem to be more adequate to prevent long-term health effects on the lower back than the exposure limits suggested by the International Standard ISO 2631/1.