Impact event and orofacial pain amid the COVID-19 pandemic in Brazil: a cross-sectional epidemiological study

Abstract Objectives This study aims to assess the impact of social isolation, due to the Covid-19 pandemic, on mental health, Temporomandibular Disorder (TMD) and orofacial pain in men and women. Methodology Individuals living in Brazil answered an online questionnaire on their sociodemographic and behavioral aspects, emotional scale (DASS-21), Impact of Event Scale, and Pain Screener in Temporomandibular Disorders (TMD-Pain Screener) during June 2020. Descriptive statistical analyses and logistic and linear regressions were applied (5% significance). Results Overall, 2301 individuals were included, 89.1% practiced social isolation, 72.6% were employed/studying, at least 15% presented severe or extremely severe levels of emotional distress and presence of powerful (34.1%) and severe impact event (15%). During the outbreak, 53.2% perceived feeling worse and 31.8% reported that orofacial pain started or worsened after the pandemic outbreak. Gender was associated with “social class” (P=0.036), “pain/stiffness in the jaw on awakening” (P=0.037), “change of pain during jaw habits” (P=0.034) and “perception of change in the situations mentioned in the TMD-Pain Screener” (P=0.020), “depression” (P=0.012), “anxiety” (P=0.006) and “impact of the event” (P=8.3E-11). Social isolation had a lesser chance to change the routine, to be practiced by the unemployed/not studying, and to be practiced by men (all with P<0.001). Associations were found between social class and all subscales of the DASS-21 and IES, all with P<0.001. Conclusions The practice of social isolation has social determinants. High levels of psychological and event impacts were detected. The presence of orofacial pain seemed to increase during the health crisis, and there were gender differences in the response to the COVID-19 pandemic.


Introduction
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), known as originated in China, caused a health crisis worldwide, being classified as a pandemic by the World Health Organization (WHO). 1 Measures of social isolation and quarantine were applied worldwide 1  Regarding Dentistry, it is important to emphasize the multifactorial nature of temporomandibular disorders (TMDs), including psychosocial causes. 5 The Diagnostic Criteria for TMD Questionnaire (DC/TMD) acknowledges the importance of the psychological and social aspects of pain. 5 It is possible to speculate an increase of severe psychological and physiological disorders, of interest to Dentistry, during the pandemic. Specialists forecast that the pandemic's influence on psychological factors may increase the risk of development, or worsening, of symptoms related to TMDs. 6 Several studies relating the difference between gender and the presence of orofacial pain and TMDs have been conducted, 7 reporting that women have a higher prevalence of presenting almost every painful symptom in the orofacial region. Some studies have shown that women report more painful experiences and have a more negative response to pain. 8 Many aspects of these differences should be noted, such as behavior, perception, pain tolerance, and the structural differences of the masticatory system. Emotions and negative stress influence pain perception and expectation. Coping ability (i.e., perceived stress) and behavior choice (exposition, fear-escape, adaptation, and no adaptation) also influence the pain experience. 9 The strategy of coping and cognition seems to be different between men and women, according to El-Shormilisy, Strong, and Meredith 10 (2015), who reported a maladaptive coping strategy and high catastrophizing levels in women. This can be important because women are twice as likely to develop TMD compared to men. 11 This study aims to assess the influence of social isolation due to the Covid-19 pandemic on mental health and on TMD and orofacial pain in men and women. The hypotheses are that there could be sociodemographic determinants for the practice of social isolation and high levels of depression, anxiety, stress; and that there is a possible relation between the emotional influence of the COVID-19 pandemic and frequent presence of orofacial pain, with notable differences between genders.

Methodology Study design
The study was performed using an epidemiological cross-sectional and analytic design. Participants answered an online questionnaire and were encouraged to pass it to others. The questionnaire was sent to different social groups through social media, emails, and message applications aiming to decrease the risk of homogeneity of participants and consequent bias.
Answers were collected in June 2020, amid the peak of the first wave of the COVID-19 crisis in Brazil.

Ethical considerations
This study was approved by the Ethics Committee of Human Research of the School of Dentistry in Araçatuba, UNESP (opinion number: 32483020.7.0000.5420).
The participants received information about the study and ethical principles. They had access to the informed consent form and choose to participate in the research by selecting the appropriate option before starting the questionnaire ("I do not wish to participate" or "I wish to participate in a free and informed way").
The recommendations of the Ethics Committee were followed, and the principles of Helsinki 12 were applied. Brazilian Portuguese and to have the cognitive ability to comprehend and answer the questions. The participants could be living in any of the five regions of Brazil, belong to any social class, and have any education level, provided that they were literate.
Individuals who did not complete the questionnaire, underaged, as well as duplicated forms were excluded from the study.

Questionnaire
The questionnaire was developed and applied

Statistical Analysis
Sample size was estimated to include 1,412 participants, considering the estimated prevalence of chronic orofacial pain in 19% the population of this study, with α = 0.05, β = 0.2, and power = 0.8. This percentage was estimated based on a pilot study with 160 participants, in which this value was found in the question "Have you had pain in the region of the head and neck, mainly on the mandible and its joint for more than three months?". The website https://clincalc.com/stats/samplesize.aspx was used to estimate sample size.
Descriptive analyses were performed for demographic data. The distribution and percentages were estimated. Quantitative statistical analyses were performed using R software (version 3.5.3; R Foundation for Statistical Computing, Austria).
Logistic regression was performed with data regarding questions on the practice of social isolation and gender as independent variables. The remaining data were analyzed as dependent variables. The probability rates (odds ratio) with superior and inferior confidence limits (95% confidence interval) were estimated.
Linear regression was applied for age, social class, and the DASS-21 and IES questionnaires, all with 5% significance.
Most participants declared to have practiced social isolation (n=2,052). On the other hand, 151 women (6.56%) and 98 men (4,25%) declared that they did not practice social isolation (n=249). Table 1 shows the distribution of demographic data according to practice of social isolation and gender.
Regarding the results for DASS-21 questionnaire, more than half of the participants were classified as "normal" in the three subscales (Depression n=1,239; Anxiety n=1,413 and Stress n=1,294). Results of "severe" and "extremely severe" counted at least 15% situations mentioned above (DASS-21 questions) were different in the last week compared to with those of the period before the pandemic?" were: "Yes, I feel they have been worse" (n=1,224=53.2%), "Yes, I feel they have been better" (n=359=15.6%); "No, I have felt the same as I did before the pandemic" (n=718=31.2%).
Regarding the IES questionnaire, the distribution of scores was: no meaningful impact (n=443=19.2%), impact event-you may be affected (n=731=31.7%), powerful impact event-you are certainly affected (n=786=34.1%), and severe impact event-this is capable of altering your ability to function (n=359=15%). Table 2 shows the distribution of answers for the TMD-Pain Screener. Answers to the question "If you answered yes to any of the questions above (TMD-Pain Screener), was this pain different from that of the period before the pandemic?" were: 1) "Yes, because the pain started after the pandemic" (n=284, 12.4%); 2) "Yes, the pain was present before the pandemic, but it has been worse" (n=445, 19.4%); 3) "Yes, the pain was present before the pandemic, but it has been better" (n=54, 2.3%); 4) "No, the pain is the same or I have not felt pain during the pandemic" (n=1518, 65.9%). Answers to the question "Have you had pain in the area of the head and neck, mainly on the mandible and its joint for more than three months?" were: "Yes" (n =679, 29.5%) and "no" (n=1622, 70.5%).

Quantitative data
The number of participants that declared to be non-binary for the question of gender was inexpressive (n=2); however, they were excluded from the quantitative analysis.

Logistic regression
Associations were found between the "practice of social isolation" and "gender", "changes in routine" and "employed/studying", all with p<0.001. Men presented 1) In the last 30 days, how long did any pain last in your jaw or temple area on either side? The questions and replies were copied and pasted from the English version of DC/TMD Assessment Instruments. 18 a 39% lesser chance of practicing social isolation.
Individuals that practiced social isolation presented a 54% higher chance of having changes in routine, and individuals that were employed/studying had a 54% chance of not practicing social isolation (Table 3).
We could not find associations between "gender" and "presence of pain in the jaw and temporalis" (p=0.070), "chewing hard food" (question 3.a from the TMD-Pain Screener) (p=0.735), "opening or moving the jaw" (question 3.b from the TMD-Pain Screener) (p=0.708), "other jaw activities" (question 3.d from the TMD-Pain Screener) (p=0.101), nor "presence of pain for three months" (p=0.102). Men presented a 28% lesser chance of having pain/stiffness in the jaw on awakening, were 1.34 times more likely to have changes of pain during jaw habits, and were 1.23 times more likely to perceive changes of situations mentioned in the TMD-Pain Screener (Table 4).

Linear Regression
Associations were found between social class and all subscales of the DASS-21 and IES, all with p<0.001 (Table 5).

Discussion
The hypotheses were confirmed, considering that   Values found by logistic regression analysis. that can affect health in various aspects, such as mental, behavioral, physical, and mortality risk. 22 The absence of such relationships may be experienced by all sporadically; however, with the COVID-19 outbreak, isolation became necessary and mandatory, affecting peoples' health and well-being. 23,24 Our study assessed the practice of social isolation and found that 89.19% of participants declared to adhere to it. Nevertheless, we emphasize that the assessment was made thought the report of "yes" or "no", presenting a possible limitation to this study, since each person considered isolation according to their own perception.
The WHO acknowledges the need for actions in mental health during the pandemic period, since an increase in symptoms of depression and anxiety have been reported in several countries. 25 The study by Wang,et al. 19 (2020) showed that, during the initial phase of the COVID-19 pandemic, more than half of the participants reported moderate to severe psychological impact and one-third reported moderate to severe anxiety. We should not only consider the psychological influence, but also pay close attention to the physiological effects that these psychiatric Values found by linear regression analysis.  15 The International Association for the Study of Pain affirms that headache and orofacial pain must last for at least three months to be considered chronic. 28 Our study collected data regarding pain for at least three months (from the beginning of the COVID-19 crisis in Brazil to the moment of data collection) and found its presence in 29.5% of participants. Although most of participants did not feel TMD-related pain, this percentage is higher than normally found in other studies, demonstrating a possible increase in orofacial pain during the COVID-19 pandemic Moreover, regarding the situations mentioned on the TMD-Pain Screener, 12.4% of participants reported that their pain started after the pandemic and 19.4% that they had had pain before, but it became worse after the pandemic. This information is important for dental professionals that must be prepared to attend to the increasing treatment demand and to understand the psychological effect of the pandemic on psychosomatic pain. The increase in TMD-related chronic pain may also occur due to the social isolation and the paucity of dental treatments for several months. Other authors also concluded that the COVID-19 outbreak has led to psychological problems such as stress, anxiety, depression, difficulty sleeping, and negative behaviors such as denial, anger, and fear, and that they deserve attention from public policies, as these changes may weaken strategies to control the COVID-19 crisis and lead to more mental health morbidities at a global level. 29 Mowbray 30 (2020) stated that the prevalence of post-traumatic stress disorder in the general population ranges from 4% to 41%. The same authors affirmed that the prevalence of major depression increased by 7% after the outbreak. 29 They cited some factors that may increase the risk of developing these conditions: female gender, lower socioeconomic status, interpersonal conflicts, frequent social media use, and lower resilience and social support, 29 which corroborates our study.
Social skills are essential to psychosocial well-being in different cultures. 31,32 However, cultural differences that must be investigated, making it difficult to directly compare studies in different cultures. For example, researchers have argued that people from more individualistic cultures (USA) seem to have more elevated social skills (e.g., due to socialization goals of parents) compared to those in collectivistic cultures, 33 and these social skills offer benefits to a person's well-being.
In 2016, social isolation and its implications were studied and their correlation with loneliness was moderate, emphasizing that both were associated with depression, considering genetic factors. 21 Logistic regression analyses showed that loneliness was more associated with depression when compared with social isolation. 21 These authors concluded that young adults in social isolation did not necessarily experience loneliness, but those who feel lonely present more signs of depression. 21 In our study, loneliness during the pandemic was not assessed, neither if the participant lived alone in this period, which could be a limitation of the study and should be further studied.
However, the emotional effect during the pandemic was high, especially in females.

Conclusion
The practice of social isolation during the COVID-19 pandemic in Brazil had social determinants. High levels of psychological and event impacts were detected.
The presence of orofacial pain seemed to increase during this health crisis, and individuals form different genders responded differently to the COVID-19 pandemic.