Association of Awake Bruxism with Tooth Wear and Occupational Stress Among Mechanical and Non-Mechanical Workers

By Fatima Tu Zahra¹, Syeda Sameen Zehra Rizvi², Amna Riaz², Amna Nisar³, Amna Khan², Naveed Ahmad²

Doi: https://doi.org/10.36283/ziun-pjmd14-1/003

How to cite: Zahra FT, Rizvi SSZ, Riaz A, Nisar A, Khan A, Ahmad N Association of Awake Bruxism with Tooth Wear and Occupational Stress Among Mechanical and Non-Mechanical Workers. Pak J Med Dent. 2025 Jan ;14(1): 10-16. Doi: https://doi.org/10.36283/ziun-pjmd14-1/003.

Received: Fri, October 11, 2024 Accepted: Wed, December 11, 2024 Published: Fri, January 10, 2025

Background: Awake bruxism, a dental and psychological health concern, is linked to physical and cognitive stress in mechanical workers, while non-mechanical workers may face higher stressors. The purpose of this analysis was to consider the association of awake bruxism with tooth wear and occupational stress in factory workers of Heavy Industries Taxila.

Methods: This descriptive cross-sectional study was conducted in Heavy Industries Taxila Factory, during a period of six months from March 2022 to August 2022 in which 245 factory workers were enrolled. Using nonprobability consecutive sampling technique.  Dental wear was assessed through the clinical examination tool BSE (bruxism Status Examination) scale by the principal investigator (BSE)after taking history using a questionnaire. Using SPSS 26 univariate and Multivariate analysis was done on factory workers involved in heavy machinery presenting with awake bruxism. The p-value of < 0.05 was taken as significant.

Results: 122 (49.8%) of the 245 were non-mechanical workers, and 123 (50.2%) were heavy mechanical workers. According to the index, the total tooth wear (SD) was 3.1±0.5 (2.9±0.4 for non-mechanical workers and 3.3±0.8 for mechanical workers). Among which, 53 (43.6%) non-mechanical workers were categorized as grade 2 and 49(40.0%) mechanical workers as grade 3. Moreover, mechanical workers had a higher prevalence of awake bruxism (56.4% versus 36.4%,). Only 33(27.3%) of non-mechanical workers acknowledged experiencing occupational stress, in contrast with 56(45.5%) of mechanical workers. The number of instances of mechanical workers who reported having both conditions was three times higher than that of non-mechanical workers (23.6% vs. 7.3%).

Conclusion: Awake bruxism tooth wear and occupational stress in participants working in a factory involved with heavy machinery exhibited significant association.

Keywords: Tooth Wear, Dental Attrition, Awake Bruxism

The surface loss of dental hard tissues brought on by causes other than dental illnesses, trauma, or developmental abnormalities is referred to as “tooth wear” or “tooth surface loss.¹.  Tooth wear is an effect of disparate mechanisms, such as erosion caused by acidic substances resulting². Dissolution of hard tissues, abrasion, ensuing as a result of exogenous materials and substances, or wearing of tooth, and attrition, caused by tooth-to-tooth contact³. Consequently, it leads to a variety of issues, including altered occlusion vertical dimensions with potential functional deficiencies, elevated tooth hypersensitivity, pulp association, uneasiness, and infrequently, reduced aesthetic appeal⁴.

The World Health Organization categorizes occupational hazards are one of the leading causes of morbidity. Tooth wear caused by awake bruxism is one of the risk factors in the workplace^5. Awake bruxism (AB) and sleep bruxism (SB) have been categorized as different behaviors recently⁵. A masticatory muscle activity characterized by repeated tooth contact, bracing, and thrusting of the jaw is defined as awake bruxism. A new system has been devised to grade and diagnose awake bruxism and categorized into three classes, labelled as “possible,” “probable” and “definite”⁶. Possible awake bruxism is diagnosed only on a positive self‐report only, while probable awake bruxism is based on a positive clinical inspection, with or without a positive self‐report. Definite awake bruxism is based on a positive instrumental assessment, with or without a positive self‐report and/ or a positive clinical inspection⁷. The signs and symptoms observed in association with awake bruxism were observed both in soft tissue and hard tissues. The soft tissue findings were mostly found to be hypertrophy of muscles and indentation marks detected on lips cheeks and tongue⁸. The hard tissue findings were mostly apparent in the form of mechanical tooth wear or cracks in tooth or cusps, sometimes mobility of teeth, failure of restorations or failure of abutments or indirect restorations on implants. The patients also complain of pain associated with the temporomandibular joint and associated structure ⁹. Headache, arthralgia, and muscular pain were also found in these patients, and most importantly tenderness and soreness of muscles of mastication⁸. The purpose of this study was to evaluate the relationship between awake bruxism, tooth wear, and occupational stress because, to our understanding, such a relationship hasn’t been explored before.

A descriptive study was employed to gauge the association of attrition due to awake bruxism among factory workers dealing with heavy machinery in HIT Taxila, Pakistan. A quantitative research methodology was developed. The sample size of 245 participants was calculated as follows: alpha error = 5%, statistical power = 90%, estimated pervasiveness in heavy machinery operators = 65%, and null = 50% ¹⁰. The data collection was carried out between March 2022 to August 2022 after approval from the ethical review board with letter number MSPH-IRB/13-31. The sampling technique was nonprobability consecutive sampling. The study was conducted in the Heavy Industries Taxila factory, and the research participants were HIT factory heavy machinery workers and factory workers not involved with heavy machinery workers of all age groups who were present in the factory during the data collection. To be eligible for the study, participants (a) possess no fewer than 21 teeth, (b) are in good general health, and (c) do not have any psychological or mental conditions. Individuals who did not submit an authorization form or had a history of long-standing systemic medical conditions were not enrolled.

Data collection was done using a questionnaire filled out by the investigator consisting of demographic information regarding age, gender, and work experience. Knight and Smith’s index was used to clinically diagnose tooth wear. The tooth wear in mechanical workers was then examined by using the BSE scale (awake bruxism status examination scale).  A thorough clinical training and awareness of two investigating dental specialists was conducted who performed the clinical examination and grading of tooth wear by employing the indices of tooth wear to increase the reliability of scores and grading, the tool has a Crohn’s back alpha of 0.7.

Prospective participants who met the inclusion requirements were invited to take part in the study by both dentists; those who agreed were asked to fill out self-administered questionnaires, and clinical data was also gathered from each participant. Since both mechanical and non-mechanical workers were included in the study, the recruitment of subjects was done in two stages: first, mechanical workers were sought out until the required sample size was reached (N = 123), and then non-mechanical workers (N = 122). The subjects responded to 11 questions on a condensed version of Karasek’s questionnaire before the dental screenings¹. It has been used in many studies and is an eminent, validated instrument to quantify occupational stress¹¹. The responses were logged in Likert scale format by designated numerical values:

High = 4 Sometimes:3 Low = 2 Never = 1.

Masticatory muscle hypertrophy, tongue or lip indentations, and/or a Linea alba on the inner cheek were among the clinical indications of both awake and sleeping bruxism. Others included mechanical tooth wear (attrition), repeated failures of prosthodontic constructions or restorative procedures, or trauma to the dental hard tissues (cracked/fractured teeth). The International Consensus on the Assessment of Bruxism’s non-instrumental approach, consisting of both clinical examination and self-report of daytime or night time bruxism, was adopted for the determination of bruxism^3,12. For continuous data, the descriptive statistics comprised means and standard deviations (SD), and for categorical variables, frequency distributions with percentages. Data was coded and recorded carefully to avoid any errors, in Statistical Package for Social Sciences (SPSS) version 26. Data analysis was done in two phases.

A chi-square test was used to analyse the differences in bruxism, occupational stress, and a combination of bruxism and high stress between mechanical and non-mechanical workers. Bruxism was then the dependent variable in a univariate and multivariate logistic regression test that controlled for confounding variables like occupational stress (low vs. high) and occupation (mechanical vs. non-mechanical). A p-value of less than 0.050 was deemed statistically significant.

Table 1: Sociodemographic of The Study Participants

The sample (N = 245) comprised of 123 heavy mechanical workers and 122 non mechanical workers. The average age was 24.8±3.2 years among the contestants, heavy mechanical workers belonged to a slightly younger age group than non-mechanical workers (28.0±5.0) years against 31.6±7.0 years). Approximately partial of the mechanical workers (49.6%) and 54.9% of non-mechanical workers had experience of ≤ 5 years, while the remainder (47.9% of mechanical workers and 47.3% of non-mechanical) had experience of > 5 years. The overall mean (SD) tooth wear (according to the index used) was 3.1±0.5 (3.3±0.8 for mechanical workers and 3.1±0.4 for non-mechanical workers). About the observation of the degree of tooth wear, 40.0% of mechanical workers were logged as grade 3, while 43.6% of non-mechanical workers were noted as grade 2. 46.4% of the total sample, history of bruxism was existing in with a higher prevalence among mechanical workers than non-mechanical (56.4% and 36.4%, respectively)

Table 2: A Correlation Between Occupation (Mechanical Versus Non-Mechanical) And High Levels of Stress, Bruxism, And Occupational Stress.

The participants’ occupational stress was assessed by using replies to the questionnaire. The survey found that compared to only 27.3% of non-mechanical workers, 45.5% of mechanical workers reported experiencing occupational stress. Further, in contrast to non-mechanical occupations, mechanical workers had a greater percentage of awake bruxism (52.7% vs. 30.9%). The proportion of mechanical workers who were afflicted by both bruxism and severe occupational stress was more than threefold that of non-mechanical workers (23.6% vs. 7.3%).

Table 3: The Dependent Variable in Both Univariate and Bivariate Logistic Regression Analysis Is the Degree of Bruxism.

Table 3 displays the results of an analysis of logistic regression with an instance of bruxism as the dependent variable. Both the univariate and bivariate logistic regression tests exhibited a significant correlation between bruxism and occupation type (mechanical vs. non-mechanical) after adjusting for occupational stress: OR = 2.6, 95% CI: 1.2.–5.8; p = 0.020 and (OR) = 2.5, 95% CI: 1.1–5.4; p = 0.016 each), respectively.

The current research identifies the Prevalence of bruxism among mechanical workers was found to be 52.7%, falling between 30.4% and 69% for other professionals. According to the literature review, this is a pioneer study that identifies the pervasiveness of dental wear due to awake bruxism in mechanical factory workers in Pakistan.

The frequency of awake bruxism ranged from 50% to 60% when compared to other populations with different professions (Brazilian police officers) characterized by stress¹³. Bruxism was noted in our study among factory workers who did not use heavy equipment. Numerous global surveys of the public revealed a prevalence of bruxism that was related to stress and unrelated to strenuous physical activity like students¹⁴. Regardless of occupation, some worldwide research reported a 20%–30% frequency in the general population^15,16. A wide variation in results between bruxism in the general population and occupational workers could be addressed by the difference in tools and methods used to assess the signs of bruxism^17,18. Bruxism is also found in association with other dental-related conditions, and they are observed and measured using different scales and assessment tools^19,20.

The current study results also show a significant association of clenching while sleep which was gauged by clinical examination and with the presence of signs and symptoms of temporomandibular joint disorders like pain and toothwear²¹. The same another study was conducted which shows that awake bruxism was reported by 15% of the population the study depicts those signs and symptoms of TMDs, as well as sleep and behavioral issues, are usually linked to sleep and wake time parafunction^6,22. The study also depicts a significant value of muscle fatigue with dental wear in heavy machinery workers as compared to non-mechanical workers. The signs of observed muscle fatigue were masticatory muscle hyperactivity indentations on the tongue and the presence of Linea alba on the buccal mucosa. Compared to another research that looked at actions such as teeth grinding and clenching along with tiredness and soreness in the lower jaw muscles utilized electromyography (sEMG) signal analysis to determine the extent of bruxism²³.

It has been demonstrated that Artificial Neural Networks improve the accuracy of awake bruxism diagnosis. When noted during a patient interview, frequent awake bruxism may be associated with persistent multifactorial stress in everyday life and at work, which may help occupational health care specialists identify more complicated stress disorders²⁴. As can be inferred from the results, there is a direct relationship between occupational stress and bruxism, and this calls for means to reduce the stress and prevent the associated symptoms found in the workers.

Jaw clenching while lifting heavy loads is involuntary, one way of overcoming this is to guide the workers to be mindful and be consciously aware of this. For this meditation and relaxation exercises could be helpful.in certain severe conditions occlusal splints and mouth guards can be fabricated to prevent undue loads on the TM joint and at the same time preclude tooth wear^21,25. Despite the sincere efforts of the researchers, a few limitations were still present in this study, foremost it was a cross-sectional study, and hence no contributory relationship can be established in this study. It is significant to note that there was no prior research to compare to evaluate the progression of tooth wear over time in study participants. Secondly, the illiterate workers were not included in the study due to the language barrier which can be a source of assortment partiality in this study. Thirdly, only male respondents were included in this study because of the non-availability of female workers in the specific unit, this may have decreased the credibility of the study concerning gender.

Within the limitations of this study, the mechanical workers in this study demonstrated significantly higher occupational stress and bruxism than the non-mechanical workers. The mechanical workers were more than three times as likely to have both stress and bruxism compared to non-mechanical workers. It is necessary to establish basic programs for the treatment and control of occupational stress and treat pathologies that may compromise the performance of heavy machinery workers.

BSE: Bruxism Status Examination

AB: Awake bruxism

HIT: Heavy industries Taxilla

SD: Standard deviations

SPSS: Statistical Package for Social Sciences

OR: Odd’s Ratio

CI: Confidence interval

TMD: Temporomandibular Disorder

EMG: Electromyography

We extend our sincere gratitude to our esteemed co-authors whose dedicated contributions were pivotal in shaping this manuscript. Their expertise, insightful inputs, and collaborative efforts significantly enriched the content and quality of the document. We would also like to express our heartfelt appreciation to the patients who generously participated in our study.

There is no conflict of interest.

The study was conducted following approval from the Ethical Review Committee of Al-Shifa School of Public Health with letter number MSPH-IRB/13-31.

The consent was obtained from the patients included in the research study.

FZ, SSZ, AR, and AN made major contributions to writing the manuscript, NA did the data collection and analysis, and AK did the formal analysis and editing.

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