Prevalence of symptoms of temporomandibular disorders, oral behaviors, anxiety, and depression in Dentistry students during the period of social isolation due to COVID-19

Abstract Temporomandibular dysfunction (TMD), anxiety, and depression are disorders that, due to the current lifestyle, are affecting an increasing portion of the population. Investigating the prevalence of the symptoms of these disorders during the quarantine due to the coronavirus 2019 pandemic (COVID-19) is important to outline clinical strategies for patient care. Objective: This study assessed the prevalence of TMD symptoms, anxiety, depression, and oral behaviors and their associations during the social isolation due to COVID-19. Methodology: Questionnaires were used to assess TMD symptoms in accordance with the Diagnostic Criteria for Temporomandibular Disorders: clinical protocol and assessment instruments, a questionnaire to verify oral behaviors and Hospital Anxiety and Depression Scale to assess symptoms of anxiety and depression in students of dentistry at the Faculty of Health Sciences of the University of Brasília in May 2020. Qualitative data were subjected to descriptive statistics and chi-squared analysis (p<0.05). The relationship between quantitative and qualitative data was evaluated using Spearman's rho correlation (p<0.05). Results: There was a high prevalence of TMD symptoms, anxiety, and depression in the participants, resulting in association between gender and anxiety symptoms (p=0.029). There was a positive correlation between oral behaviors and TMD symptoms (r=0.364; p<0.001), between oral behaviors and anxiety symptoms (r=0.312; p=0.001), and between oral behaviors and symptoms of depression (r=0.216; p=0.021). Conclusion: Social isolation due to the COVID-19 pandemic has an impact on the prevalence of TMD symptoms, anxiety, and depression.

can be transmitted from one person to another through close contact, leading to COVID-19. 3 Infected patients can develop severe respiratory distress, requiring intensive care, and can be fatal. 1,3 Owing to this scenario, several countries in the world are adopting restrictive quarantine measures to control the spread of the virus and the collapse of health systems.
It is not uncommon for people with a confirmed diagnosis or with suspected COVID-19 to experience great psychological pressure. Health professionals are also susceptible to these problems, as they must care for infected patients, to decrease or, in some cases, to restrict living with their family, among other factors. 4 In addition, people who are quarantined, fulfilling social isolation, restricted to leave, concerned about infection, afraid of death, lack information, and who have lost daily social relationships, can further experience high levels of anxiety and depression. 5 Psychological factors are associated with the development of some diseases and disorders, including temporomandibular disorders (TMD), which is a collective term used to describe disorders related to temporomandibular joints (TMJs) and masticatory muscles, which are primarily responsible for the movement of TMJs and related structures. 6 The etiology of TMD is multifactorial, including the combined action of environmental, biological, psychological, biomechanical, and neuromuscular factors. 6,7 Symptoms are generally jaw pain, ear pain, toothache (of non-dental origin), joint pain, headache, and mandibular functional limitation. 8,9 More than 50% of the population present some level of TMD, but only 3.6% to 7% require treatment. 10 The highest prevalence is in women aged 20 to 40 years. 10 Currently, the bio-psychosocial model studies the etiology of TMD due to biological factors, such as genetic or biochemical factors, psychological factors, such as anxiety, stress, and depression, and social factors, such as culture, family behavior, and socioeconomic status. However, the mechanisms by which psychological factors influence the development of TMD remain unknown. 7 Therefore, studies that assess the influence of the COVID-19 pandemic, and its consequences on TMDs are important. Thus, the objective of this study was to assess the prevalence of TMD symptoms, anxiety, depression, and oral behaviors and their associations during the social isolation due to COVID-19. The null hypothesis is that there will be no association between TMD symptoms, anxiety, depression, and oral behaviors.

Methodology
This was a cross-sectional study performed on dental medicine students from the School of Health Sciences of the University of Brasília (FS/UnB). The study was approved by the National Council of Ethics in Research (CAAE: 30637620.2.0000.0008).
A minimum sample size of 104 participants was determined based on the size of the student population of this course of 220 students, an accuracy of 5%, an estimated prevalence of 15%, and a 95% confidence interval, using an online sample size calculator. (http:// sampsize.sourceforge.net/iface). All students of both genders were invited to participate in the research.
All subjects signed an informed consent form before participation. Students on medication for anxiety and/ or depression were excluded.
Due to the impossibility of clinical evaluation because of the social isolation due to COVID-19, the evaluation of TMD symptoms, oral behaviors, anxiety, and depression was carried out through questionnaires, applied between May 12 and 19, 2020, and made available through a QR code and link, which was sent to class e-mails and disseminated on social networks.
General data such as name, age, gender, and medication use were collected. In addition, the following was asked: How is your isolation going? Total social isolation -without ever leaving home; Partial social isolation -at home, but going to the market, pharmacy, and other essential services, or; No isolation -I am not performing social isolation.
Are you carrying out any physical activity at home? Prevalence of symptoms of temporomandibular disorders, oral behaviors, anxiety, and depression in Dentistry students during the period of social isolation due to COVID-19 J Appl Oral Sci.

Assessment of anxiety and depression
The Hospital Anxiety and Depression Scale (HADS) was used to assess symptoms of anxiety and depression. It is made of 14 items, 7 of which assess anxiety (HADS-A) and 7 depression (HADS-D). 12 Each of its items can be scored from 0 to 3, making up a maximum score of 21 points for each scale. 13 Responses to the HADS items were obtained to assess frequency of anxiety and depression. The No association was found between TMD symptomatology and gender, anxiety symptoms, depression symptoms, type of social isolation, and physical activity ( Table 1). The association between anxiety symptoms and gender was verified [X2 (2) = 4,769; p=0.029]; however, there was no association between anxiety symptoms and type of social isolation and physical activity ( Table 2). There was no 2020;28:e20200445 4/8 association between depression symptoms and gender, type of social isolation, or physical activity (Table 3).
There was a positive correlation between oral behaviors ( using the OBC) and TMD symptoms (ρ=0.364 and p<0.001), between oral behaviors and anxiety symptoms (ρ=0.312 and p=0.001), and between oral behaviors and symptoms of depression (ρ=0.216 and p=0.021) ( Table 4).

Variables
With anxiety symptoms   which can result in muscle overload, local ischemia, and pain. 32 The frequency of oral behaviors is increased in patients with greater anxiety. 33  Thus, investigations about the influence of the pandemic and its consequences on TMDs should be carried out to better understand the current situation, and how it will influence the post-pandemic in orofacial pain. The major limitation of the present study was that it was carried out in a very specific population.
Therefore, the results cannot be extrapolated convincingly to the general population.