Temporomandibular joint disorder among Peruvian music students of different instrumental specialties

1. Introduction

Music, often considered one of the most sublime human expressions, is not without physical implications for those who produce it. Professional and amateur musicians, regardless of the instrument they play or the musical style they practice, are exposed to several physical challenges that can have a significant impact on their well-being.¹ One of the most prevalent but least studied health problems in this population is craniofacial and temporomandibular pain. Temporomandibular pain is a common problem, with estimates suggesting that up to one-third of the population may experience symptoms at some point in their lives. However, it is important to keep in mind that the prevalence may vary significantly depending on the population studied, the methodology used, and the definition of temporomandibular joint disorder employed in the study.²

Although the scientific literature has extensively explored musculoskeletal ailments in musicians, such as carpal tunnel syndrome or tendonitis, there is a gap regarding the assessment of pain-associated disabilities in the craniofacial and temporomandibular region. It is plausible to assume that they may be at increased risk due to the muscle strain associated with practicing and performing their art.³

Disability associated with craniofacial and temporomandibular pain in musicians is a phenomenon that can be influenced by a combination of biomechanical, psychological and occupational factors. Postures and techniques, fundamental to the art of music making, can also be the epicenter of biomechanical stress that could lead to craniofacial and temporomandibular pain and disability. The biomechanical complexities of playing a musical instrument cannot be underestimated. And then there is posture. The way a musician positions himself or herself in relation to his or her instrument can have enormous repercussions. A stooped posture or an incorrect head angle can strain the musculature and joints of the craniofacial area, creating fertile ground for the appearance of temporomandibular problems. Let us not forget the phenomenon of overuse either. The muscles of the face and jaw, like any other muscle in the body, have their limits. In the heat of practice or during marathon performance sessions, these limits can easily be exceeded. The resulting muscle fatigue can become a critical factor contributing to the development of painful conditions in the craniofacial region. Even technique, that holy grail of musical mastery, can be a double-edged sword. Poor technique can multiply the biomechanical load on the craniofacial structures. On the other hand, even “correct” technique is no guarantee against the risk of disability, as the physical demands of musical performance often transcend anatomical capabilities.⁴

The aim of this study was to determine the differences in the frequency of temporomandibular joint disorder among music students of different instrumental specialties.

2. Methods

The research was applied, with an observational, cross-sectional, and descriptive correlational design.

Our study followed the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines for cross-sectional studies. The study was approved by the Research Ethics Committee of the School of Stomatology of the Universidad César Vallejo with Official Letter No. 0103-2023-/UCV/P, dated December 20, 2023. We adhered to the principles of the Declaration of Helsinki. Written informed consent was obtained from all participants.

3. Results

The sample studied is significantly skewed towards the male sex, representing 71.4% (25 out of 35) versus 28.6% of women (10 out of 35). The median age of the participants is 23 years, with an interquartile range of 21 to 25 years, suggesting a young population. In terms of marital status, the majority are single (97.1%), probably reflecting their stage of student life.

Regarding dental occlusion, there was a predominance of Class II (51.4%), followed by Class I (31.4%) and Class III (17.1%).

The instrumental specialty is evenly distributed among five categories, each with 20% of the total number of participants.

Regarding temporomandibular joint disorder, 14.3% of the students had no signs or symptoms, while 60.0% showed mild TMJD, 22.9% moderate TMJD and 2.9% severe TMJD.

Finally, the mean stress score for students is 44.7, with a standard deviation of 5.6, which could indicate moderate levels of stress in this population.

The distribution of musical instruments practiced by students is diverse, ranging from guitar in the plucked string category (20%), to wind, percussion and bowed string instruments, with varied representations. For example, in bowed string, the double bass is practiced by 8.6% of the students, while the cello, violin and viola have smaller representations. In metal wind, trombone and trumpet are practiced by 8.6% and 5.7% respectively. In percussion, timpani stand out with 11.4%. Finally, in woodwind, the saxophone is practiced by 8.6% of the students.

The time since they started playing their specialty instrument shows a median of 9 years, with an interquartile range of 8 to 12 years. This indicates considerable experience in their musical specialty. In addition, weekly practice with their specialty instrument has a median of 20 hours, reflecting a high degree of commitment and practice.

Interestingly, 82.9% of the students also practice other instruments in addition to their major, suggesting musical versatility, but also possibly overcharge. The time spent weekly practicing their major and other instruments has a median of 23 hours.

Table 1 presents a detailed analysis of the relationship between sociodemographic factors, dental occlusion, instrumental specialty, stress and the presence of temporomandibular joint disorder (TMJD) in music students. The data are structured according to the severity of TMJD, grouped into categories of no signs and symptoms, mild, moderate and severe TMJD.

In terms of sex, no significant differences were observed in the frequency of TMJD (p=0.827), with a similar proportion between women and men in each TMJD category.

Regarding age, similar means were observed among the different degrees of MDD, varying slightly between 21.7 and 23.8 years, but without statistically significant differences (p=0.579). This homogeneous trend suggests that age is not a clear differentiating factor in the prevalence of TMJD in this population.

The molar ratio presents a varied distribution in the different degrees of TMJD, with a slight tendency to a higher prevalence of mild TMJD in Class II and Class III, but without statistically significant differences (p=0.577).

Regarding instrumental specialty, variations in the distribution of TMJD according to specialty were observed, but no statistically significant differences were found (p=0.222) in the bivariate analysis.

Finally, the stress score, although varying slightly between groups (44.4 in no TMJD, 45.7 in mild TMJD, 42.1 in moderate TMJD and 47 in severe TMJD), does not show significant statistical differences (p=0.490), indicating that the level of perceived stress does not correlate obviously with TMJD severity.

Table 2 examines the proportion ratio (PR) of temporomandibular joint disorder (TMJD) in music students, considering variables such as instrumental specialty, molar ratio, practice time and instrument weight. The table presents results from both a simple model and an adjusted model, which allows a deeper understanding of the factors that could influence the prevalence of TMJD.

In the instrumental specialty analysis, the simple model shows a statistically significant association in metal wind and woodwind students, with PR of 0.04 (95% CI [0.00; 50.04] and 0.03 (95% CI [0.00; 0.56] respectively, indicating a lower proportion of TMJD compared to the reference (Plucked string). In a post-regression test, we also found a difference in the prevalence of TMJD in metal wind students compared to percussion students (p=0.030) and in the prevalence of TMJD in percussion students compared to woodwind students (p=0.025).

However, in the adjusted model, these majors maintain a significant association (PR of 0.04; 95% CI [0.00; 50.04] and PR=0.03; 95% CI [0.00; 0.56], respectively), suggesting that, even after adjustment for other variables, students in these majors have a lower prevalence of TMJD. On the other hand, Bowed string and percussion group show no significant differences in either model. In a post-regression test, we also found a difference in the prevalence of TMJD in metal wind students compared to percussion students (p=0.032) and in the prevalence of TMJD in percussion students compared to woodwind students (p=0.045).

4. Discussion

In our study, we have identified that instrumental specialty is a determining factor in the frequency and severity of temporomandibular joint disorder among music students. We observed that those who play metal wild and woodwind instruments have a lower prevalence of temporomandibular joint disorder compared to pulsed students. We also found a difference in the prevalence of TMJD in metal wind students compared to percussion students and in the prevalence of TMJD in percussion students compared to woodwind students.

There are several factors that might explain why students who play metal wind and woodwind instruments exhibit a lower prevalence of TMJD compared to those who play plucked string instruments. Musicians who play wind instruments tend to adopt a more ergonomic posture and experience less stress on the jaw. The technique of using diaphragmatic breathing can distribute tension more evenly throughout the body, thereby reducing the load on the jaw muscles. In contrast, playing plucked string instruments, such as the guitar, often requires postures and techniques that generate more tension in the jaw and neck, particularly when these instruments are played for extended periods without adequate breaks. The biomechanical load also varies between these types of instruments. Wind instruments necessitate a controlled and specific use of facial and mandibular muscles, which might promote balanced muscle development and less strain in these areas. On the other hand, the tension in the hands, arms, shoulders, and neck while playing plucked string instruments can translate into tension in the jaw due to the rigid posture and muscle stress associated with playing techniques. Additionally, the muscle use involved in playing these instruments differs. Correct technique for playing wind instruments involves repetitive movements that are less likely to harm the jaw, as they engage a controlled range of motion. In contrast, plucked string instruments may involve repetitive and sustained jaw movements, especially if the musician sings and plays simultaneously, which could increase the tension in the temporomandibular joint. Similarly, in percussion, the muscles involved may adopt repetitive and vigorous postures and movements that can generate greater tension in the jaw and neck due to the nature of striking and handling drumsticks or mallets.

The relationship between our research and the studies conducted by Reijani N and Benetti FA⁸ is particularly revealing. In their study, Reijani and Benetti found that a significant proportion of musicians experienced musculoskeletal problems, highlighting how posture and technique used during instrumental practice can directly influence musculoskeletal health. This link is particularly pertinent in the context of our research, which demonstrates how musicians, who are likely to adopt specific postures and perform repetitive movements, have lower prevalence of temporomandibular joint disorder. The convergence of these findings underscores the need for greater awareness and prevention in terms of posture and technique among musicians, especially those in specialties more susceptible to musculoskeletal conditions.

In addition, the results of Clemente MP et al.⁹ provide a deeper understanding of how specific physical characteristics, such as craniofacial morphology, may influence the musician's experience and prevalence of related pain. Their study, focused on wind instrument players, analyses the relationship between different classes of malocclusion and mouth opening during musical performance. By finding significant differences in mouth opening between musicians with different malocclusions, Clemente et al. highlight the relevance of craniofacial morphology not only in musical performance, but also in predisposition to conditions such as temporomandibular joint disorder. This complements our findings, suggesting that certain physical characteristics may influence the development of TMJD.

The studies by Bourne D et al. and Vastamäki M et al.¹⁰ provide crucial insight into how sustained and repetitive musical practice, especially among string orchestra players, may be a significant contributing factor to the development of musculoskeletal pain. Bourne and colleagues, through a phenomenological approach, highlighted that the pain experienced by string players affects not only their musical performance, but also various aspects of their daily lives, thus evidencing the multifaceted impact of performance-related pain. Vastamäki M et al. quantified this phenomenon, showing a higher prevalence of musculoskeletal pain in orchestral musicians compared to the general working population. Comparison between these studies and ours suggests that certain instrumental specialties, due to their unique physical demands, may predispose musicians to a higher incidence of musculoskeletal conditions such as temporomandibular joint disorder. In addition, the study by Kaczorowska A et al.¹¹ brings an additional dimension to this discussion. By finding that both the intensity and frequency of musculoskeletal pain in musicians are related to the amount of time spent practicing, this study reinforces the idea that the duration and intensity of instrumental practice are critical factors in the development of musculoskeletal conditions. We observed that all music students are required to practice for many hours each day. This is important to consider in future research, despite our not finding any differences, possibly due to the small sample size.

These intersections between the studies and our research underscore the complexity of temporomandibular joint disorder in musicians. They highlight the importance of considering a variety of factors, from posture to instrumental technique and practice, for a comprehensive approach to the prevention and management of TMJD in this specific population.

In acknowledging the limitations of our study, it is critical to consider that, although we have included and measured stress as a key variable, there are other factors that we have not assessed that could have influenced the results. These factors include specific pain management techniques and the individual medical history of the participants. However, these limitations do not undermine the robustness of our findings, as our study provides an important basis for understanding the relationship between instrumental specialty and temporomandibular joint disorder in musicians. Considering many variables not addressed in other studies and focusing specifically on the music student population ensures the relevance of our results.

Looking forward, the limitations of our study open avenues for future research. These studies could further explore how other individual factors interact with the physical demands of instrumental specialties in the development and management of temporomandibular joint disorder. This could lead to the development of more specific and effective strategies to prevent and treat temporomandibular joint disorder in musicians, considering both the physical demands of their musical practice and psychosocial aspects such as stress. This future research could provide a more detailed and comprehensive understanding of the multiple factors that influence temporomandibular joint disorder in the musician population.

Our central finding highlights instrumental major as a significant factor in the prevalence of temporomandibular joint disorder among music students. Furthermore, we suggest the need for additional research that explores how the combination of stress management strategies and music practice techniques may influence the prevention and treatment of temporomandibular joint disorder. This conclusion leads us to recommend the implementation of educational and training programs that focus on ergonomics and instrument-specific techniques to minimize the risks of developing this condition.

Ultimately, our findings not only contribute to the field of musicians' health, but also establish a foundation for future research that seeks a more complete understanding of how the various aspects of a musician's life and practice interact and affect his or her physical and psychological well-being. By addressing these areas, we will be able to significantly improve the quality of life and the sustainability of musicians' careers.

5. Conclusion

There are significant differences in the prevalence of temporomandibular joint disorder (TMJD) among music students, which vary according to their instrumental specialty. Students who play metal wind and woodwind instruments show a lower prevalence of TMJD compared to those who specialize in pulsed instruments. Also, there are a difference in the prevalence of TMJD in metal wind students compared to percussion students and in the prevalence of TMJD in percussion students compared to woodwind students.

Ethics and Consent

The study was approved by the Research Ethics Committee of the School of Stomatology of the Universidad César Vallejo with Official Letter No. 0103-2023-/UCV/P, dated December 20, 2023. We adhered to the principles of the Declaration of Helsinki. Written informed consent was obtained from all participants.