Ergonomic Interventions in the Dental Setups and Their Role in Preventing Musculoskeletal Disorders among Dentists: A Systematic Review

Abstract

Dentists are susceptible to work related musculoskeletal disorders (WMSDs) due to the extensive hand dexterity and endurance required for performing various dental procedures. This systematic review will evaluate the randomized controlled trials that have implemented physical and cognitive ergonomic interventions in a population of dentists to prevent WMSDs. The research question was formulated by using the population-intervention-comparison-outcome format. Relevant articles were identified from various databases, such as PubMed, PubMed Central, and ScienceDirect. Two reviewers analyzed the study characteristics and conducted the final analysis of the five selected studies. The quality of the included studies was assessed independently by both authors using the Effective Public Health Practice Project Quality Assessment Tool. The risk of bias was assessed using RevMan software 5.4.1. In this review, five randomized controlled trials were included. The two reviewers demonstrated good agreement (κ = 0.63, 95% confidence interval [CI]: 0.45-0.821, p < 0.005) during the screening stage and very good agreement (κ = 0.8, 95% CI: 0.65-1.000, p < 0.005) during the eligibility stage. Studies incorporating physical and cognitive ergonomic interventions demonstrated a significant reduction in symptoms associated with musculoskeletal disorders. Cognitive interventions, when introduced early in a dentist’s career, can raise awareness and guide them on the dos and don’ts of comfortable ergonomics while achieving patient-friendly treatment.

INTRODUCTION

According to the International Ergonomics Association, Ergonomics is ‘the scientific discipline concerned with the fundamental understanding of interactions among humans and other elements of a system, and the application of appropriate methods, theory and data to improve human well-being and overall system performance’ [1]. Musculoskeletal disorders (MSDs) caused due to work is defined as an injury to the bones, cartilage, muscles, tendons, blood vessels, ligaments or nerves, aggravated primarily by the performance of a particular work in a certain work environment [2,3]. Dental professionals work for long hours in a static position and is these takes a toll on the body. Dentists are prone to work related musculoskeletal disorders (WMSDs) because of the high degree of hand dexterity and endurance required to perform various dental procedures. All the treatments are performed in a confined and restricted workspace; the oral cavity. WMSDs have been identified as a significant occupational health risk among dental professionals [4].

Globally, the prevalence of non‐specific WMSDs among dental professionals is estimated to be between 49% and 92% [5,6]. The clinical environment itself poses a high risk for developing WMSDs among dentists as the nature of dental procedures cannot be performed without assuming uncomfortable positions and non‐neutral wrist positions. When working on teeth in the contra-lateral quadrants or in the maxillary posteriors, the dentists have to work resisting gravity [7]. Forward head posture is a position where is the head is positioned in front of the body’s vertical midline. This type of abnormal posture can lead to joint and connective tissue damage leading to pain and disability [8]. Other MSDs complaints among dentists are lower back pain, neck pain, cervico-brachial pain, shoulder tendinitis, De Quervain syndrome, carpal tunnel syndrome, and Guyon syndrome [9].

The European Society for Dental Ergonomics defines dental ergonomics as the adaptation of the working environment and working techniques, with respect to their physical and psychological capacity for healthy, safe, and comfortable functioning in their professional activity. The International Ergonomic Association classifies ergonomics into three specific categories. Physical ergonomics in dentistry refers to any interventions that will enable the operator to work with minimal strain on the body like adopting the right dental chair positions and apt instrumentation. The second category of ergonomics is cognitive ergonomics that consists of awareness programs and lectures on the importance of ergonomics. The third category of ergonomic interventions are the organizational ergonomics that includes optimization of work policies, work flow, appointment scheduling and other related factors [10]. This systematic review will assess the randomized controlled trials that have used physical and cognitive ergonomic interventions in a population of dentists to prevent WMSDs.

RESEARCH QUESTION

The research question was formulated by using the PICO format. The research question of this systematic review was formulated as ‘Can ergonomic interventions prevent MSDs in dentists?’ The PICO of the research question is as follows:

P- Population: Dental professionals

I- Intervention: Ergonomic intervention

C- Control group

O- Outcome measure: Prevention of MSDs

METHODOLOGY

The Cochrane guidelines (Cochrane Collaboration) for systematic reviews was followed for the identification of studies. Relevant articles were identified from various databases like PubMed Central and science direct. The initial screening of articles was done by screening of titles and abstracts. Duplicate articles were removed in the process. The full text of the selected articles was retrieved and completely analyzed according to the selection criteria. The selected articles were included in the current systematic review.

1. Search methodology

The search methodology was carried out in PubMed database and science direct using a list of selected keywords.

2. Registration

The current systematic review was registered in the International Prospective Register of Systematic Reviews Database (Registration number: CRD42023487270).

3. Criteria for study selection

The search dates for the studies included in this review were from 2018 to 2023. The searches were subjected to initial analysis followed by a final analysis. Unpublished studies from grey literature were excluded. In the search criteria all randomized clinical trials with any ergonomic intervention that was done in a population of dentists were included. Apart from physical interventions, the studies that used cognitive interventions like awareness programs, educative sessions in the form of didactive lectures were included in the analysis. Studies that followed a hybrid method of intervention where both physical and cognitive interventions were also included. Questionnaire studies, observational studies were excluded from the review. Studies done with a population of dental hygienists or dental assistants were also excluded. Once the intervention is introduced, the dental professionals fill self-assessment forms regarding their ease and comfort in performing routine dental procedures before and after the intervention. Self-assessment can be designed in the form of questionnaires, pictorial representation like a happy or sad face, graphs, scores indicating the understanding of using an intervention, using a rubric to identify strengths and weaknesses in one's capability to utilize a new tool etc. The search also yielded case control studies that evaluated the effectiveness of physical and cognitive ergonomic interventions in dental professions.

4. Study synthesis

This systematic review included 2 reviewers for application of the eligibility criteria and selection of studies for inclusion in the systematic review (one person will screen and others will re-check the final decision). RevMan 5.4.1 software (Cochrane Collabration) was used for decision making process. The interrater agreement in the screening and eligibility stages is reported using the Cohen’s kappa coefficient (κ).

5. Quality assessment

The quality of the included studies was assessed independently by both authors using, the Effective Public Health Practice Project Quality Assessment Tool. Authors have stated that this tool is suited for use in systematic reviews of effectiveness and has been reported to have content and construct validity [11]. The tool assesses 6 domains: selection bias, study design, confounders, blinding, data collection method and withdrawals/dropouts. Each domain can be rated as strong (1 point), moderate (2 points) or weak (3 points). Any disagreement in the ratings was resolved with discussion, and the interrater agreement is reported using the Cohen’s kappa coefficient (κ).

6. Data extraction

Only randomized controlled trials conducted with dental professionals as population were extracted. A total of three reviewers checked the data (i.e., One person was involved independently for the data extraction and two persons checked the extracted data). The disagreements between individual judgements were resolved at each phase of the systematic review starting from search strategy till the final process of the manuscript. Data was recorded using RevMan 5.4.1.

The software was used to record the data for the population selection, sample size, type of intervention, control group, outcome measures, results and inference of all included studies. One person was used to review the procedure of study selection and two reviewers were involved in the quality assessment.

RESULTS

1. Literature evaluation

This systematic review included five studies in total and were thoroughly examined (Table 1) [12-16]. Five studies which were randomized controlled trials were included in the review. The sample sizes ranged from 17 to 135 subjects with an average of 63 subjects. Two studies followed physical intervention, two studies followed cognitive intervention and one study followed a combination of physical and cognitive intervention. For assessing the outcome of interventions, one study used Branson’s modified posture assessment instrument (PAI), one study used M-DOPAI, another used RULA and the last study used both WAI and CMQ assessment tools. The 2 reviewers demonstrated good (κ = 0.63, 95% confidence interval [CI] = 0.45 to 0.821, p < 0.005) and very good agreement (κ = 0.8, 95% CI = 0.65 to 1.000, p < 0.005) at the screening and eligibility stage, respectively.

Table 1.

Characteristics of the studies included in the systematic review

Author, year of publication	Study design and evidence level	Sample distribution	Type of intervention	Study and control group	Outcome measure	Results	Follow up	Inferences
Bud et al. [12] (2021)	Randomized controlled trial	17	Physical ergonomic (PE) intervention: Dental loupes, dental operating, microscope	Study group: Dental students prepared cavity with dental loupes and dental operating microscope Control group: Dental students prepared cavity with unaided vision	Branson’s modified posture assessment instrument (PAI)	The use of the direct operating microscope (DOM) improved the overall posture of the students by 36%, with an average PAI score difference of 0.70 points (p < 0.0001) when compared to the unaided eye vision technique. The use of loupes also confirmed out expectations and improved the overall posture of the students by 8.9% (p = 0.0041)	-	The study showed significant improvement of the working posture using magnification systems compared to direct vision. The biggest improvement was obtained through the use of DOM, followed by the dental loupes. Students perceived dental loupes as being the most comfortable and easy to adapt to. They reported being more focused when using DOM
Faust et al. [13] (2021)	Randomized controlled trial	41	Cognitive ergonomic intervention: 2-hour didactic lecture on ergonomics and correct operator and patient positioning	Study group: The case group received additional 1-on-1 instruction with facilitators trained in effective ergonomic postures and positioning (21) Control group: Students who don’t receive 1-on-1 instructions on ergonomics (20)	Hip flexion lumbar placement shoulder abduction neck flexion, thoracic posture (in relation to forward head posture), lateral flexion of the spinal column, elbow flexion (corresponds with height of the patient chair), and the angle of the patient’s maxillary or mandibular arch	Statistically significant differences in the mean values were noted between the case and control groups in the areas of operator shoulder abduction (p = 0.029), and lateral flexion of the spinal column (p = 0.021). The mean composite ergonomic positioning score was also statistically significantly different between the 2 groups (p = 0.005)	-	Hands on instruction with physical therapists and trained dental faculty positively affects ergonomic compliance and provides students with tailored feedback that can be applied to clinical practice
Lin et al. [14] (2022)	Randomized controlled trial	135	Cognitive ergonomic intervention: 45-min ergonomic lesson about basic knowledge on MSD prevention and control PE intervention: 235 ergonomic changes in their daily dental practices were made, including work posture, repetitive motions, tool usage, work break relaxation, and work time re-arrangement	Study group: Dentists received 45-min ergonomic lesson about basic knowledge on musculoskeletal disorder (MSD) prevention and control followed by working group meetings on 235 ergonomic interventions (125) Control group: Dentists received only a 45-min ergonomic lesson about basic knowledge on MSD prevention without any further meetings or discussions (13)	Quick exposure check Work ability index (WAI) Chinese Nordic musculoskeletal questionnaire Work posture, repetitive motions, tool usage, work break relaxation and work time re-arrangement with total 235 ergonomic changes in the trail	The changes in MSD prevalence and WAI during the 1-year follow-up. Compared to the prevalence of baseline, MSDs on neck, low back and wrists/hands were significantly reduced after 9-month or 12-month in the intervention group, while no significant changes were found in the control group during the follow-up	1 year	PE intervention is effective in reducing ergonomic risk exposure and MSDs on neck and wrists/hands among young dental professionals. The findings from this current study suggest that PE should be offered as early as the dental career starts, to reduce the possibility of MSDs among dental profession
Partido et al. [15] (2020)	Randomized controlled trial	30	Cognitive ergonomic intervention: Discussion of ergonomic principles, recognizing harmful postures, and practicing ergonomics evaluations using sample photographs	Study group: Dental educators received feedback involving photography and self-assessments Dental educators in the training group had two additional photographs taken (front and profile) and completed an ergonomic self-assessment (M-DOPAI) with the physical intervention Control group: Dental educators received feedback involving photography and self-assessments only	Modified-dental operator posture assessment instrument (M-DOPAI) Photography and self-assessment	From week 1 to week 4, the ergonomics training utilizing photography resulted in improvements in the dental educators’ ergonomic scores but not the accuracy of their ergonomic self-assessments	-	In this study, the ergonomics training utilizing photography resulted in improvements in dental educators’ ergonomic scores but not the accuracy of their ergonomic self-assessments
Pispero et al. [16] (2021)	Randomized controlled trial	90	PE intervention: Dental loupes, dental operating, microscope	Study group: Dentists performed tooth extractions with dental loupes and dental operating microscope Control group: Dentists performed tooth extraction with unaided vision	Rapid upper limb assessment (RULA) evaluated using 2D marker	Naked eye and medical loupes interventions there is a high risk, confirming the results in while, for the surgical microscope, the total risk is classified just as ‘low’	-	2D marker when applied to dental surgery, allowed us to estimate the risk of work related musculoskeletal disorders for different visual aids, pointing out that using the surgical microscope is less fatiguing than medical loupes and the naked eye

2. Study characteristics and quality assessment

Four studies concluded that there were significant improvement of the working posture using magnification systems compared to direct vision. Three studies found significant improvement in the operating positions after providing ergonomics training and self-assessment of photography. The main characteristics of the included studies are summarized in Table 1 [12-16]. The agreement between the reviewers in the quality assessment stage was very good (κ = 0.86, 95% CI= 0.754 to 0.98, p < 0.005).

3. Risk of bias

All studies had an unclear risk of bias with respect to the blinding of outcome data. There was low risk for selective reporting in all the studies. The allocation concealment and performance bias had a high risk of bias in all the studies. Selection bias had a low risk of bias in the study by Bud et al. [12] and Partido et al. [15] whereas selection bias was a high-risk parameter in studies by Faust et al. [13], Lin et al. [14], and Pispero et al. [16]. The assessment of risk of bias is given in Fig. 1.

Fig. 1.

Assessment of risk of bias.

DISCUSSION

According to the National Institute for Occupational Safety and Health of the U.S, MSDs refer to specific conditions that affect the nerves, tendons and muscles, and support structures like the intervertebral discs. MSDs include a wide range of conditions with a range of severities from mild, intermittent to chronic debilitating symptoms [17]. MSDs have become a major complaint among dentists. The majority of dentists experience muscle pain at some point during their professional life. Although an occasional backache or neck pain may not seem important, frequent ignorance of such pains may result in the development of a chronic disability [18]. Risk of MSDs manifesting as pain in different body parts is high in dental profession due to various factors like the repetitive nature of work, long working hours in static positions without breaks, incorrect posture during the procedures, application of excessive force, and use of wrong instrumentation [19]. Studies have explained the occurrence of WMSDs in dental practitioners, after considering factors like the number of work hours per day, number of years worked, work intensity, force used during cavity preparation or scaling, nature of procedures, type of instruments, work-rest cycles, etc., The available data are too scattered, and are obtained through subjective, self-assessment tools or observation, and thus they lack objective measurements and defined criteria. Specific guidelines for dentists with respect to WMSDs are documented in limitedly. The current systematic review aimed to provide sound, scientific, and evidence-based data on ergonomic interventions for dentists.

Magnification devices improve direct and indirect vision while performing various dental procedures. Dental loupes are the most commonly used devices for magnification, due to the affordable prices and the ease of use without making major changes in the working protocol or ergonomics. They are available in multiple variants and models offering magnifications up to 6.5×. The most common magnification used is 2.5×. Authors have reported a number of benefit while using loupes like improvement in ergonomics and posture, easier evaluation/detection of dental conditions and overall treatment quality. Several studies have stated that dentists can perform better restorative treatments under microscopic view due to the precise diagnosis and proper completion of the treatment. A magnified image of the operative field may help the dentist to check cavity preparations, rubber dam and matrix fitting, saliva infiltration, dentine debris, composite layering, occlusal morphology, macro/micro details, air voids, and tooth contours in a better way [20].

In the included studies, under physical interventions, authors had used a combination of dental loupes and dental operating microscope in two studies. In the clinical trial by Pispero et al. [16], the posture of dentists while performing extraction of third molars were recorded using three-dimensional acquisitions. There was a significant reduction in neck traction during the procedure while using dental loupes and dental operating microscopes. The other study recorded the ergonomics of dental students while preparing class I cavities. The PAI scores were significant when the dental students performed the procedure using direct operating microscope (DOM) and dental loupes compared to unaided vision. The scores obtained while working with the unaided eye, dental loupes and dental operating microscope were statistically significant, for all three body segments analyzed namely; trunk, head and neck, shoulders [12].

In the 5 studies included in this systematic review, three studies used cognitive interventions in dentists. Under cognitive intervention, didactic lectures were given to dentists through one-on-one instructions. Awareness lectures on how to prevent WMSDs, details on the right operator and patient positions were discussed. The studies used digital photography as a tool by which photographs of the dentists working on the patients were captured. These photographs were used along with assessment forms to educate the dentists on their postural deficiencies. Cognitive interventions involving lectures and feedback involving photography and self-assessments had significant improvements on the participant’s understanding of ergonomics in both the studies [13-15]. The findings of our analysis were similar to a review by Rivilis who found that participatory ergonomic interventions lead to better health outcomes by reducing injuries among workers thus reducing their compensation claims. The workers also were regular to work by avoiding sick leaves. The need for organizational support through availability of resources, alternate rest break schedules for the dentists, flexible timings, rotational duty, cross-functional training, communication, quality management and routine ergonomic trainings are immaterial in achieving ideal ergonomics at dental workplaces. Our findings were in consensus with the results of another systematic review that studied articles between 1993 and 2014 on the effect of ergonomic interventions on employees and their health. The authors found that more than half of the studies showed positive outcomes after the use of different ergonomic interventions [21]. Similarly, when particular dental intervention tools and techniques are incorporated according to the different work environments, there can be better quality of work with higher work efficiency.

CONCLUSION

Ergonomics in dentistry is a much-needed topic of concern considering the increase in WMSDs among the dental professionals. Ergonomics should strike a balance between keeping the dentist healthy and providing efficient treatment. Physical interventions in the form of magnification tools should be introduced as part of dental curriculum. Cognitive interventions when given to dentists at an early stage in their careers can provide good awareness and guide them on the dos and don’ts of comfortable ergonomics while achieving patient friendly treatment. Better ergonomical considerations will undoubtedly improve the quality of work, quality of life, personal health and productivity. In the current analysis, we found that physical interventions like magnification loupes, DOM provide better ergonomic outcomes by reducing the incidence of MSDs. Further our findings indicate that multicomponent intervention program that comprises of a combination of any two or three interventions like physical and cognitive or physical and organizational interventions can help achieve a better health and enhance work performance among dentists. Such multicomponent programs can be a solution when it is aptly integrated with optimal ergonomics training. A comprehensive approach incorporating participatory ergonomic techniques along with long term follow up can reduce the incidence and prevalence of WMSDs among dental professionals. We also suggest that physical interventions like dental loupes, magnification loupes, DOM should be made mandatory at all hospitals and dental clinical setups thus making it a part of routine practice. Implementation research in all levels of organization should be introduced so that the physical and emotional welfare of dental healthcare professionals who work for long hours are prioritized.

Funding Statement

• Funding: None.