Occupational injuries (OIs) remain a major problem in many industrialized countries, and the prevention of workplace accidents is important because of their high socioeconomic impact. In 2020, the Swiss accident insurance agency reported more than 800,000 injuries to the Accident Insurance Statistics Collection Office (SSUV), including approximately 264,311 occupational injuries and illnesses (ACCIDENT INSURANCE STATISTICS UVG 2021).
Occupational injuries associated with temporary or permanent disabilities and illnesses result in days away from work. This is significant because temporary or permanent incapacity to work leads to economic losses for the country and social problems for the affected employers, employees and their families (UNSAR ET AL. 2009). Existing studies on the prevalence of workplace injuries show that the medical profession and the construction industry, including the automobile industry, are associated with an increased risk of occupational injuries (EMPLOYER-REPORTED WORKPLACE INJURIES AND ILLNESSES 2020). Therefore, automotive mechanics who diagnose, adjust, repair or overhaul motor vehicles are statistically more likely to get injured on the job than the average worker (BUREAU OF LABOR STATISTICS 2019). Previous studies indicate that automotive mechanics and technicians are exposed to a variety of chemical and physical hazards, such as high noise levels and non-ergonomic working conditions (BEJAN ET AL. 2001; BLAKE ET AL. 2008; COHEN ET AL. 2008; DOTSON ET AL. 2006; FREDRIKSSON ET AL. 2001; HAGBERG ET AL. 1995; SOROCK ET AL. 2004; VANDERGRIFT ET AL. 2012). Frequent contact with work-related objects and equipment, such as automotive parts, materials and vehicles, represents a significant risk factor.
Occupational injuries often occur due to equipment tipping over, falling or collapsing, resulting in sudden major traumatic injuries as well as minor cuts and burns (BUREAU OF LABOR STATISTICS 2019). The most commonly affected body parts of mechanics are the hands, back, shoulders, eyes and knees (BUREAU OF LABOR STATISTICS 2019). Such workplace injuries can also involve maxillofacial areas, including the mouth, teeth and periodontal tissues (ZALECKIENE ET AL. 2014). The reported prevalence rates for occupational traumatic dental injuries (TDIs) range from 6% to 39%. Data from various studies show that one-third of adults have suffered work-related trauma to the permanent dentition (ZALECKIENE ET AL. 2014). Traumatic dental injuries often result in increased tooth mobility, crown/root fractures, dislocation, or avulsion. Moreover, occupational injuries to anterior teeth in the esthetic zone generally lead to more demanding restorative treatments associated with higher economic burdens for the affected workers and their families (KRASTL ET AL. 2011; SOLIMAN ET AL. 2020). Although occupational orofacial injuries are common, there is a lack of scientific data on the topic of occupational health and safety in Europe and Switzerland (LÓPEZ-ARQUILLOS ET AL. 2016; UGOLINI ET AL. 2018). To the best of our knowledge, there are no studies to date on work-related orofacial injuries and oral trauma in the automotive repair industry in Switzerland. Therefore, various researchers have recognized the importance of collecting data to improve our understanding and awareness of occupational injuries and the importance of worker protection in the automotive sector (GUSEVA CANU ET AL. 2020).
This study was conducted to evaluate the self-reported prevalence of occupational trauma to the head, including traumatic dental injuries (TDIs), among automotive repair workers involved in the repair and maintenance of motorcycles, cars and vehicles over 3.5 tons.
Materials and methods
To survey vehicle repair workers in Switzerland from 2019 to 2021, we sent a questionnaire to 1000 randomly selected automotive repair workshops out of approximately 6331 in Switzerland. A total of 121 workers responded, yielding a response rate of 12%: 98% (n=119) were healthy mechanics currently or previously employed in automotive repair and maintenance involving motorcycles, cars and vehicles over 3.5 tons at the targeted repair workshops and were thus included in the study. The exclusion criteria were as follows: (1) persons who were minors, (2) persons who did not perform work/repair/maintenance on motorcycles, cars or vehicles over 3.5 tons. All individuals included in the study participated voluntarily. The study was approved by the ethics committee of the University of Basel, Switzerland (approval number swissethics: Req-2020-00728).
All 121 study participants completed the study questionnaire, which was written in German. The questionnaire was divided into six sections and contained a total of 12 questions. Section 1 collected demographic data (gender), Section 2 information regarding the subjects’ profession, education and professional experience, Section 3 investigated protective measures and Section 4 captured data on occupational injuries among automotive repair and maintenance workers handling motorcycles, cars and vehicles over 3.5 tons. Section 5 involved the description and treatment of pain, and Section 6 the incidence of traumatic dental injuries in childhood. The German to English translation of the questionnaire is shown in Supplementary Table I.
Statistical analyses were performed using the Tidyverse 1.3.0 package within the R statistical programming environment, version 3.5.3 (The R Foundation; Vienna, Austria). Differences between groups were analyzed by Fisher's exact tests. The chi-squared test was used to test for association between categorical variables (e.g., sex and profession). A logistic regression model was used to predict a history of work-related injury (yes versus no) adjusted for gender and years of employment. The odds ratio (OR) was calculated along with the corresponding 95% confidence interval (CI) and p-values. The level of significance was set at p < 0.05 (two-sided).
After screening for compliance with the inclusion criteria, a total of 119 healthy participants were enrolled in the survey. Two respondents were excluded because they did not meet inclusion criteria. The vast majority of participants (94%) were male.
Profession, education and professional experience
According to the self-reported questionnaire data, the most common profession was automotive mechanic (n=54, 45%), followed by automotive mechatronic technician (n=28, 23.5%), and automotive specialist (n=20, 16.8%). Among the 119 participants, 70 (59%) reported more than 10 years of professional experience, 32 (27%) had 4-10 years of experience, and 13 (10.9%) were in professional training. Furthermore, 112 (94%) of the surveyed individuals worked full-time and 92% were involved in car repair.
105 respondents (88.2%) used protective gear such as goggles (n=95, 90.5%), hearing protection (n=62, 59%), breathing masks (n=49, 47%), helmets (n=11, 10.5%), and mouthguards (n=2, 1.9%), while 14 (13%) worked without personal protective gear (Figure 1). Of the persons reporting workplace accidents, 30 (28.6%) had one to three occupational injuries to the head or teeth.
Regarding the question of whether they had suffered an occupational injury in an automotive repair shop, most of the respondents answered “YES” (n=85, 71.4%). The most commonly injured parts of the body were the hands (n=72, 84.7%), followed by the arms (n=27, 31.7%), feet (n=17, 20%), and legs (n=15, 17.6%) (Figure 2). Moreover, the most common types of OIs were lacerations (n=51, 60%), contusions (n=36, 42.3%) and burns (n=32, 37.6%). Thirty-seven (31%) of 119 participants reported an OI to the head or tooth region, and 19 of them required one (n=13, 10.9%) or more (n=8, 6.7%) medical or dental treatment center visits for these injuries. Tooth involvement was reported in 16 of 37 cases (43.2%); the most common type of occupational TDI was tooth fracture (11.8%; p=0.191) (Figure 3). Interestingly, 57 (81.4%) of the participants who reported occupational injuries in general, 26 (37.1%) who reported occupational injuries to the head or teeth, and 9 (12.9%) who reported work-related tooth fractures had more than 10 years of professional experience (Figure 4).
Influence of traumatic dental injuries in childhood
Thirty-eight participants (31.9%) had traumatic dental injuries in childhood. Childhood TDI increased the odds of occupational injury to the head or teeth by a factor of 2.4 (n=17, 95% CI: 1.1, 5.5, p=0.036) (Figure 5). Furthermore, traumatic dental injuries during childhood increased the odds ratio for occupational injury in general by a factor of 1.5 (n=33, 95% CI: 0.4, 6.1, p=0.54) in automotive repair and maintenance workers.
Worldwide, approximately 270 million work-related injuries occur annually, resulting in a loss of 3.5 healthy life years per 1,000 workers (BARLING ET AL. 2004; CONCHA-BARRIENTOS ET AL. 2005). Several studies indicate that automobile repair work is a perilous occupation with an increased injury prevalence (BEJAN ET AL. 2001; BLAKE ET AL. 2008; COHEN ET AL. 2008; DOTSON ET AL. 2006; SOROCK ET AL. 2004; VANDERGRIFT ET AL. 2012). Although traumatic dental injuries are common among individuals with multiple occupational injuries, there are no studies to date on the prevalence of work-related TDIs in automotive repair shops in Switzerland (EILERT-PETERSSON ET AL. 2011). Therefore, the current study aimed to identify factors associated with occupational injuries and dental trauma in the automotive repair industry in Switzerland. Furthermore, we analyzed the data to identify effective protective measures for automotive mechanics and technicians.
Most participants in our survey (n=85, 72%) had a history of occupational injury. The incidence rate observed here is in accordance with that of Vyas et al., who found occupational injuries in 63% of mechanics in automotive repair workshops (VYAS ET AL. 2011). Additional studies indicate that automotive mechanics have an increased prevalence of injuries to the hands and upper extremities (BUREAU OF LABOR STATISTICS 2019; VYAS ET AL. 2011).
Similarly, our survey revealed that the most commonly affected parts of the body were the hands, followed by the arms, feet and legs, and that 37 of 85 participants (43.5%) had sustained occupational injuries to the head or tooth region. Traumatic dental injuries including lateral luxation, intrusion and avulsion can lead to long-term tooth loss due to periodontal damage arising from either replacement resorption or infection-related root resorption (HERSBERGER ET AL. 2012; PERSIC ET AL. 2006). Furthermore, dental trauma is frequently associated with complex dental restorative treatments (e.g., tooth replacement or prosthetic rehabilitation), resulting in an increased economic burden (REICHARDT ET AL. 2021; UGOLINI ET AL. 2018).
Several investigators reported a different prevalence range for occupational traumatic dental injuries (ZALECKIENE ET AL. 2014). The epidemiological study by Ugolini et al. 2018 indicated a low prevalence of 5.6 per 1000 work-related traumatic dental injuries (UGOLINI ET AL. 2018). Remarkably, the total number of those occupational injuries was statistically comparable with that in construction, farm, and factory workers. Our survey revealed a high prevalence of dental traumatic injuries in automotive repair workers: 13.4% out of 119 participants. This figure is elevated compared to that of the aforementioned study (UGOLINI ET AL. 2018). Furthermore, in the study by Ugolini et al., the highest prevalence of work-related TDIs occurred in the fourth and fifth decades of life and in males compared to females. We were unable to confirm the latter finding due to the preponderance of males in the present survey. Most of our participants with occupational injuries to the head or teeth, including tooth fractures, had more than 10 years of professional experience. This finding is consistent with that of Hansen et al., who detected an association between years of work experience and occupational injuries in aging male construction workers in Denmark and concluded that physical work demands are a significant risk factor for occupational injuries (HANSEN ET AL. 2022).
Baidwan et al. found that aging workers who perceived their workplaces to be high in psychological and physical work demands and efforts had a nearly two times greater risk for occupational injuries than those who did not (BAIDWAN ET AL. 2019). Hence, it can be assumed that the risk of occupational injury increases with age and work experience in occupations with high physical work demands, such as automotive repair and maintenance.
The results of our survey showed that traumatic dental injuries during childhood increased the odds of automotive repair workers having an occupational injury in general by a factor of 1.5 (p=0.544), and increased their odds of occupational injury to the head or teeth 2.4 fold (95% CI: 1.1, 5.5, p=0.036) (Figure 5). In agreement with these findings, Filippi & Krastl observed that the leisure behavior of children and adolescents has become more aggressive and risk-taking than in the past (FILIPPI & KRASTL 2007). There is an annual increase in traumatic dental injuries, including those associated with “trendy” sports equipment, such as inline skates, kickboards and water slides in swimming pools. Moreover, epidemiological studies have shown that traumatic dental injuries occur in about 55 out of every 100 children in Europe and the USA before they reach the age of 16 (BORSSÉN ET AL. 2000; KASTE ET AL. 1996). The most common types of trauma to the teeth were dislocation in the primary dentition and crown fracture in the permanent dentition (FILIPPI ET AL. 2007). Various studies have shown that age, gender and traumatic dental injuries in childhood may also influence the prevalence of work-related dental trauma (ROCCIA ET AL. 2013; TRULLÁS ET AL. 2013; UGOLINI ET AL. 2018). The results of our survey of Swiss automotive repair workers highlighted the need for even more effective safety strategies for certain parts of the body.
These findings coincide with the results of the American Bureau of Labor Statistics, which indicate that the head, especially the eye region, is one of the most commonly affected parts of the body (BUREAU OF LABOR STATISTICS 2019). In our study sample, the predominant use of eye, hearing and breathing protection is probably why no occupational injuries were reported in those sensitive parts of the body. On the other hand, the lack of protection of the face, head and teeth increased the odds of having occupational injuries, including dental trauma. According to Ugolini and co-authors, the upper jaw and upper incisors are the most commonly involved sites of occupational injuries involving the head and teeth (UGOLINI ET AL. 2018). Accidental tooth loss (knock out) occurred in one automotive mechanic included in the present survey. Moreover, tooth fractures were the most common type of workplace dental trauma reported in the present study (14 out of 16 participants). This rate is similar to that in the Italian study (UGOLINI ET AL. 2018).
Besides dental fractures of different types, pain can also be an effect of traumatic dental injuries. The results of our survey indicated that among the 16 participants with dental injuries, the majority reported a dull, pulsating pain that lasted for more than one hour. Most of these cases required a dental or medical treatment center visit. Hence, protective measures are important in professional fields like the automotive industry. In view of the different hazards in their workplace, automotive mechanics can most effectively protect themselves against traumatic dental injuries by wearing a mouthguard.
Additionally, they should be informed about the use of a tooth rescue box in the rescue chain for avulsed teeth (BRUNNER ET AL. 2009; KIRSCHNER ET AL. 2013; MÜLLER ET AL. 2008). The results of the present study indicate that Switzerland has reached a higher standard of protective equipment for automobile workers compared to other countries (VYAS ET AL. 2011).
However, mechanics and technicians should be trained about special protective tools even more frequently. The wearing of mouthguards or helmets to prevent injuries to the head and face area is crucial as these parts of the body are more frequently affected by occupational injuries than others (BRUNNER ET AL. 2009; KIRSCHNER ET AL. 2013; MÜLLER ET AL. 2008).
Hence, it is important to customize, adapt and implement occupational safety information and disease prevention programs to improve the health status of automobile repair workers according to the individual needs of the specific local conditions. Moreover, because well-designed studies on this topic are lacking, additional research is needed to reduce the number of work-related injuries in this occupational field.
Limitations of this study
One limitation of this study is that the prevalence of occupational injuries was calculated based on employee self-reported data rather than medical or administrative data sets. A further limitation has to do with the small size of the study sample.
Several studies indicate that automotive repair work is a perilous occupation with an increased risk for work-related injuries. Additionally, it is reported that automotive mechanics have a high prevalence of injuries to hands, arms, and head, including the teeth. The results of the present survey documented the predominant use of eye, hearing and breathing protection in Switzerland and, accordingly, the study participants reported no injuries in those sensitive parts of the body. On the other hand, the use of additional protective gear, such as mouthguards or helmets, could have prevented traumatic injuries to the head and tooth region but, apparently, many of the respondents failed to do so.
Accordingly, the surveyed automotive mechanics reported a high prevalence of injuries to the hands, extremities, head and teeth, including traumatic dental injuries. The most common type of dental trauma reported in this survey was tooth fracture. The present survey also indicates that age, gender and traumatic dental injuries accidents in childhood may also influence the prevalence of occupational injuries. The results of this questionnaire survey highlight the need for more protective gear, especially for the head and teeth, in the automotive industry and similar fields. Moreover, Information campaigns to improve the health status of automobile repair workers are another important issue.
Acknowledgements: The authors would like to thank P791 car residence AG for their support.
Conflict of interest: The authors declare that they have no conflict of interest.
Funding: No external funding was received for this research.