ORIGINAL RESEARCH article

Front. Public Health, 08 July 2022

Sec. Occupational Health and Safety

Volume 10 - 2022 | https://doi.org/10.3389/fpubh.2022.899582

Adverse Impacts of Temporomandibular Disorders Symptoms and Tooth Loss on Psychological States and Oral Health-Related Quality of Life During the COVID-19 Pandemic Lockdown

  • 1. Department of Stomatology, Clinical Traditional Chinese Medicine College of Yangzhou University, Yangzhou, China

  • 2. Department of Gastroenterology, Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China

  • 3. Health Management Center, Affiliated Hospital of Yangzhou University, Yangzhou, China

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Abstract

Background:

Emotion and quality of life may have been impacted by the coronavirus disease 2019 (COVID-19) crisis, especially in the lockdown. The impact of temporomandibular disorders (TMD) symptoms and tooth loss on mental status and Oral Health-Related Quality of Life (OHRQoL) are not fully understood in a stressful situation.

Objectives:

We aimed to investigate whether TMD and tooth loss were the impaired risks of psychological states and OHRQoL in COVID-19 lockdown, and attempt to explore other potential risk factors.

Methods:

This cross-sectional study surveyed residents via an online self-reported questionnaire, when Yangzhou was in lockdown. Demographic data, clinical information, the level of anxiety, depression and OHRQoL were collected and analyzed.

Results:

Painful TMD symptoms and tooth loss are the risks of more severe anxiety and depression. TMD symptoms and tooth loss worsened OHRQoL. Lower education degree (OR: 6.31, P = 0.019), TMD-related pain symptoms (OR: 10.62, P = 0.005), tooth loss (OR: 3.12, P = 0.035), sleep disorders (OR: 2.92, P = 0.049) and relatively close contacts (OR: 3.95, P = 0.020) were verified as risk factors for increased level of anxiety. With respect to depression, low socio-economic status (OR: 6.22, P = 0.021), TMD-related pain (OR: 7.35, P = 0.012), tooth loss (OR: 4.48, P = 0.009), sleep disorders (OR: 5.13, P = 0.007) and relatively close contacts (OR: 12.94, P = 0.001) were identified as independent factors for developing depression. Additionally, drinking (B: −2.584, P = 0.013) and never going to the dental clinic (B: −3.675, P = 0.024) were relevant to better OHRQoL, while TMD without pain (B: 2.797, P = 0.008), TMD-related pain (B: 12.079, P < 0.001), tooth loss (B: 2.546, P = 0.006), sleep disorders (B: 2.598, P = 0.003) were independent factors for impaired OHRQoL.

Conclusion:

Painful TMD symptoms, tooth loss and sleep disorders were the impaired risks of psychological states. TMD symptoms and tooth loss damaged OHRQoL when the city was in lockdown. Therefore, individualized psychological counseling is supposed to maintain control of mental health and OHRQoL under the stressful event.

Introduction

Temporomandibular disorders (TMD) are a group of conditions that cause pain and dysfunction of the masticatory muscles, temporomandibular joint (TMJ), and the surrounding musculoskeletal structures (1). Being the third most prevalent social dental disease, TMD affects about 10–15% population across the world and the incidence is still rising (2, 3). Typical symptoms of TMD include local pain, limited mandibular movement, and TMJ sounds during movement (4). The etiology of TMD still remains elusive, accumulating evidence suggests that factors from biologic, environmental, social, emotional, and cognitive aspects all play an indispensable role in the occurrence and development of TMD (5). Among these triggers, the contribution of psychological issues involved in emergency or threatening situations like the ones faced with the coronavirus disease 2019 (COVID-19) pandemic, to the onset and duration of TMD has been acknowledged by more and more researchers (6, 7). Psychological and socio-demographic factors, including somatization, depression, stress, anxiety, daytime sleepiness, optimism, gender and age, aggravated pain intensity and pain-related disability in patients with TMD (8). In turn, previous studies showed that TMD patients exhibited higher level of psychological disorders such as anxiety and depression compared with healthy controls (911). Patients with self-reported TMD-pain reported higher scores for anxiety, depression, and somatic symptoms compared to patients with no TMD-Pain complaint (12). In addition, ample evidence demonstrates that tooth loss is negatively associated with depression, anxiety and Oral Health-Related Quality of Life (OHRQoL) (13, 14), which is in line with the observation that effective treatment of tooth loss have positive effects on quality of life and mental status (15). Collectively, the influence of the bidirectional relationship between psychosocial and physical factors deserves further clinical attention.

Since the end of 2019, a novel, threatening pandemic, the COVID-19 caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) infection, caused a health crisis worldwide (1618). Many countries adopted a policy of lockdown aiming to decelerate the contagion, which subsequently made dramatical changes of the daily lifestyle of the residents, and negatively influenced the mental health of individuals (19, 20). Recent studies implicated that outbreak of COVID-19 was supposed to cause emotional disorders, cognition dysfunction, behavioral disturbance and impaired quality of life, especially in population with psychosomatic diseases such as coronary heart disease, irritable bowel disease and psoriasis, in whom psychological distress and somatic diseases could mutually influence one another (2124). Regarding dentistry, most of the studies indicated adverse effects of COVID-19 on psycho-emotional status (stress, anxiety, depression), which lead to the intensification of TMD symptoms and increased orofacial pain (OFP) (25). However, few studies have examined whether some dental problems may be the risk factors of the mental health and OHRQoL during COVID-19 lockdown.

Dental clinic is confronted with potential risk of transmitting COVID-19. On one hand, multiple dental procedures using ultrasound instruments tend to produce aerosol fog of saliva or blood droplets in the workplace, which has been proven to be a potent carrier of the virus (26); on the other hand, the execution of dental treatment involves close contact between dentist and patients, which further exacerbates the possibility of human-to-human transmission (27, 28). Thus, according to the American Dental Association (ADA) recommendation, all dental treatments, in addition to the emergency treatment, should be delayed.

There was a COVID-19 outbreak in Yangzhou, a tourist city in Eastern China. It was a resurgence of the coronavirus since Wuhan lockdown. Before this resurgence, the pandemic of COVID-19 in China had been at stable status. To cope with it, the government took strict lockdown measures. This cross-sectional study was performed using an online questionnaire to explore potential risk factors of the altered psychological status and OHRQoL during Yangzhou lockdown, thereby modifying the variables for which intervention is feasible, and optimizing the management of susceptible people. We assume that TMD or tooth loss are the risk factors of higher levels of anxiety and depression as well as poorer OHRQoL.

Methods

Participants

Due to the impossibility of clinical evaluation because of the social isolation, the evaluation of TMD symptoms, OHRQoL, anxiety, and depression was carried out through online questionnaires. The questionnaires were edited through the Wen-Juan-Xing online platform. Then, an electronic two-dimensional code of the questionnaire was created. When Yangzhou was in the lockdown, every residential district has its own WeChat group. A lot of information about epidemic lockdown was sent through the WeChat group, and the questionnaires were randomly distributed to those groups by the group advocates. All the subjects were residents in these enclosed districts, and the sample size collected during the opening hour had reached the expectation. A total of 300 online questionnaires were randomly distributed, but 23 individuals were excluded from the analysis, including 9 were diagnosed with psychological diseases at the time of our study; 10 had other physical disorders closely related to their psychological state, and the remaining 4 cases did not provide sufficient information. The inclusion criteria were as follows: (1) those who were residents in these enclosed districts during Yangzhou lockdown. (2) volunteered to participate in research. The exclusion criteria included (1) those who did not answer the questionnaire in the opening hours; (2) those who were diagnosed with psychological diseases at the time of our study; (3) those who had other physical disorders closely related to their psychological state. According to Peduzzi et al. (29) and Concato et al. (30), the sample size satisfied the following analysis. This survey was conducted 1 month after the implement of the lockdown. All protocols in the study were carried out in accordance with the principles of the Declaration of Helsinki. This study was approved by the Institutional Review Board and Ethics Committee of Clinical Traditional Chinese Medicine College of Yangzhou University (REC ref 2021-29). We obtained their authorization by signing the informed consent.

Data Collection

The first part of the questionnaire collects basic information of the participants, including gender, age, occupation, education, economic level, marital status, etc. The second part is some issues related to the epidemic, for example: Were you close contacts of any confirmed cases or familiar with someone who is confirmed case? Have you been vaccinated? Did you join in the voluntary service against the epidemic in the local community?

The third part mainly assesses the presence of symptoms related to TMD. On the basis of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), which was translated and validated into Chinese with objective questions about TMD symptoms. The answered questionnaires were analyzed by a specialist in the field and the participants were classed into three groups according to their symptoms: without TMD symptoms, with non-painful TMD symptoms, or painful TMD symptoms (31). In this part, there are also some issues about sleep disorder, tinnitus, tooth loss and so on.

The fourth part focuses on the psychological status and OHRQoL of the responders. The Generalized Anxiety Disorder Scale 7 (GAD-7), which assesses the patient's anxiety over the past month, consists of seven questions, each with four choices, with scores ranging from 0 to 3, for a total of 21 points. The higher the score is, the worse the anxiety is. A score of 0–4 is classified as normal, 5–9 as mild anxiety, 10–14 as moderate anxiety and 15–21 as severe anxiety (32). Depression was assessed with Patient Health Questionnaire-9 (PHQ-9). There are nine questions, each score is 0–3 points, with a total score of 27 points. Zero to four is minimal depression, 5–9 mild, 10–14 moderate, 15–19 moderately severe and 20~27 severe (33). To evaluate the OHRQoL of the participants, the Oral Health Impact Profile-14 (OHIP-14) scale was applied. It covers 14 items in seven areas with five choices in each item. The score is 0 to 4 for each item with a total score of 56, which is inversely proportional to the level of OHRQoL (34).

Statistical Analysis

Statistical analysis was performed using SPSS version 22.0 (IBM SPSS Statistics, USA). Continuous variables were presented as mean ± standard deviation (SD) and categorical variables were presented as proportions. Univariate logistic regression was performed to identify potential modifiers of psychological stress.

In univariate analysis, the screening criteria for candidate predictors was P < 0.05. Then, multivariate analysis was further used to eliminate the variables with no statistical significance. P < 0.05 in multivariate analysis was considered statistically significant. Odds ratios (OR) were applied to measure the correlation between variables and outcomes of psychological stress.

Using the added scores of OHIP-14 as a continuous outcome, multiple linear regression analyses were performed adjusted for all variables. The coefficients 95% confidence intervals (CI) for Beta and P-values were calculated.

Result

A total of 300 online questionnaires were randomly distributed among the lockdown population, 23 individuals were excluded as described above. Basic information is shown in Table 1. The age is mainly distributed in the 30–40 stage, and the male: female ratio was 103:174. Seventy- seven percent were married, 17.33% single, and 6.14% divorced. In regard to the occupation, 28.88% worked in state -owned units; 31.41% in private units; 23.47% worked freelance; and the remaining 16.25% had retired. In terms of education level, 78.34% got a bachelor's degree or higher. Smokers and drinkers accounted for 11.91% and 20.58%, respectively.

Table 1

VariablesMean ±SD or n (%)
Gender, n (%)
    Male103 (37.18%)
    Female174 (62.82%)
Age, years (mean ± SD)
    20–30
 30–40
 40–50
 50–60
 60–70
37 (13.36%)
110 (39.71%)
41 (14.80%)
57 (20.58%)
32(11.55%)
Marital status, n (%)
    Married212 (76.53%)
    Single48 (17.33%)
    Divorced17 (6.14%)
Occupation, n (%)
    State-owned units80 (28.88%)
    Private units87 (31.41%)
    Freelance work65 (23.47%)
    Retired45 (16.25%)
Education level, n (%)
    Elementary4 (1.44%)
    Middle school56 (20.22%)
    Bachelor or above217 (78.34%)
Socio-economic status, n (%)
    Very low28 (10.11%)
    Low84 (30.32)
    Middle79 (28.52%)
High86 (31.05%)
Smoking33 (11.91%)
Drinking57 (20.58%)
Vaccination232 (83.75%)
Voluntary service119 (42.96%)
Relatively close contacts123 (44.40%)
Frequency of going to the dental clinics, n (%)
    Regular check28 (10.11%)
    Seldom34 (12.27%)
    When necessary188 (67.87%)
    Never27 (9.75%)
Sleep disorders145 (52.35%)
Tinnitus97 (35.02%)
Tooth loss87 (31.41%)
TMD symptoms, n (%)
    No symptoms of TMD206 (74.37%)
    Symptoms of TMD without pain51 (18.41%)
    Symptoms of TMD with pain20 (7.22%)

Demographic characteristics of patients included in the study.

Concerning the TMD symptoms, most participates (74.37%) did not report any symptoms of TMD, 51 patients suffered from TMD without pain, while the rest complained of TMD with pain. A total of 145 patients (52.35%) reported sleep disorders. Tinnitus and tooth loss were present in 35.02% and 31.41% patients, respectively. When talking about the frequency of going to the dental clinics, 10.11% of the participates had a regular check, while the majority turned to a dental clinic when necessary. After the outbreak of the epidemic, 119 patients in our study joined in the voluntary service against the epidemic in the local community, and most of the population (83.75%) accepted vaccine injection. In addition, 123 (44.40%) were considered as relatively close contacts.

When using 5 as the cut-off value for the GAD-7 scale, the incidence of anxiety was 46.21% (128/277), with 86 in the mild group, 23 in the moderate group and 19 in the severe group (Table 2). In terms of depression, 117 (42.24%) scored ≥5 for the PHQ-9 scale, regarded as the existence of depression, and among these, 82 (29.60%) presented mild depression, 19 (6.86%) moderate, and 16 (5.78%) moderately severe. During the closure, the mean score of the OHRQoL assessed by OHIP-14 is 11.22 ± 7.66.

Table 2

Variablesn (%)Mean ±SD
Anxiety (GAD-7)
    No149 (53.79%)1.96 ± 1.39
    Mild86 (31.05%)7.01 ± 1.29
    Moderate23 (8.30%)11.35 ± 1.20
    Severe19 (6.86%)15.42 ± 1.43
Depression (PHQ-9)
    No160 (57.76%)1.99 ± 1.26
    Mild82 (29.60%)5.99 ± 1.09
    Moderate19 (6.86%)11.87 ± 1.07
    Moderately severe16 (5.78%)16.63 ± 1.49
    Severe0/
OHRQoL(OHIP-14)11.22 ± 7.66

Level of anxiety, depression and OHRQoL among patients included in the study.

To explore the influencing factors of anxiety in the situation of COVID-19 lockdown, we first applied univariate logistics regression to screen potential variables. As shown in Table 3, compared with retired, working in state-owned [OR: 0.30 (95% CI: 0.10–0.88), P = 0.028) or private units [OR: 0.33 (95% CI: 0.11–0.95), P = 0.040] tended to have lower anxiety. Lower education degree [OR: 5.45 (95% CI: 2.34–12.72), P < 0.001], poorer socio-economic status, regular check at the dental clinics, [OR: 17.85 (95% CI: 1.73–184.56), P = 0.016], TMD-related pain [OR: 14.46 (95% CI: 3.89–44.79), P < 0.001], tooth loss [OR: 2.12 (95% CI: 1.02–4.44), P = 0.044], sleep disorders [OR: 3.10 (95% CI: 1.18–8.19), P = 0.022], tinnitus [OR: 5.53 (95% CI: 2.49–12.51), P < 0.001] and relatively close contacts [OR: 4.58 (95% CI: 1.74–12.05), P = 0.002] were significantly related to higher anxiety. After adjustment by multivariant analysis, lower education degree [OR: 6.31 (95% CI: 1.35–29.37), P = 0.019], TMD-related pain [OR: 10.62 (95% CI: 2.07–54.59), P = 0.005), tooth loss [OR: 3.12 (95% CI: 1.08–8.99), P = 0.035], sleep disorders [OR: 2.92 (95% CI: 1.003–15.30), P = 0.049) and relatively close contacts [OR: 3.95 (95% CI: 1.24–12.60), P = 0.020] were verified as risk factors for more severe anxiety.

Table 3

VariablesUnitivariable analysisMultivariable analysis
POR95%CIPOR95%CI
Gender (male)0.1960.580.25–1.33
Age
    20–300.1530.170.01–1.94
    30–400.2580.470.13–1.74
    40–500.9060.910.21–4.02
    50–600.8750.890.22–3.61
    60–70
Marital status
    Married0.3560.540.15–1.99
    Single0.2300.350.06–1.94
    Divorced
Occupation
    State-owned units0.028*0.300.10–0.880.2882.960.40–21.85
    Private units0.040*0.330.11–0.950.4082.220.34–14.57
    Freelance work0.4730.670.22–2.02
    Retired
Education level
    Elementary 00.2015.450.41–73.18
    middle School<0.001*5.452.34–12.720.019*6.311.35–29.37
    Bachelor or above
Socio-economic status
    Very low<0.001*22.894.66–112.510.05411.370.96–135.37
    Low0.025*3.151.15–8.610.0783.330.87–12.76
    Middle0.028*3.071.13–8.350.0523.530.99–12.60
    High
Smoking0.5310.640.16–2.62
Drinking0.4820.700.27–1.87
Frequency of going to the dental clinics
    Regular check0.016*17.851.73–184.560.4433.220.17–64.46
    Seldom0.0828.080.77–84.69
    When necessary0.0736.830.84–55.81
    Never
Voluntary service0.6030.820.39–1.71
Vaccination0.7441.170.46–2.97
TMD symptoms
    No symptoms of TMD
    Symptoms of TMD without pain0.6760.810.30–2.16
    Symptoms of TMD with pain<0.001*14.463.89–44.790.005*10.622.07–54.59
Tooth loss0.044*2.121.02–4.440.035*3.121.08–8.99
Sleep disorder0.022*3.101.18–8.190.049*2.921.003–15.30
Tinnitus<0.001*5.532.49–12.510.3141.760.59–5.27
Relatively close contacts0.002*4.581.74–12.050.020*3.951.24–12.60

Factors associated with elevated anxiety.

*

, P < 0.05 was considered significant.

With respect to depression, after using univariate logistics regression to screen potential variables, we performed multivariant analysis. Low socio-economic status [OR: 6.22 (95% CI: 1.33–29.14), P =0.021], TMD-related pain [OR: 7.35 (95% CI: 1.55–34.81), P = 0.012], tooth loss [OR: 4.48 (95% CI: 1.45–13.80), P = 0.009], sleep disorders (OR: 5.13 (95% CI: 1.55–16.98), P = 0.007] and relatively close contacts [OR: 12.94 (95% CI: 2.98–56.15), P = 0.001] were identified to be independent factors for progression of depression (Table 4).

Table 4

VariablesUnitivariable analysisMultivariable analysis
POR95%CIPOR95%CI
Gender (male)0.4500.710.29–1.74
Age
    20–300.4510.370.03–5.00
    30–400.1690.390.10–1.49
    40–500.8071.220.25–6.07
    50–600.4110.560.14–2.25
    60–70
Marital status
    Married0.7031.270.37–4.41
    Single0.5470.550.08–3.87
    Divorced
Occupation
    State-owned units0.0680.360.12–1.08
    Private units0.1070.410.14–1.21
    Freelance work0.3970.600.18–1.95
    Retired
Education level
    Elementary0.1835.890.43–80.32
    Middle school0.002*3.911.65–9.250.1922.240.67–7.49
    Bachelor or above
Socio-economic status
    Very low0.003*7.891.99–31.280.4112.290.32–16.56
    Low0.030*3.481.13–10.770.021*6.221.33–29.14
    Middle0.0812.720.88–8.34
    High
Smoking0.3690.5330.14–2.10
Drinking0.8030.870.30–2.51
Frequency of going to the dental clinics
    Regular check0.2593.960.36–43.29
    Seldom0.8200.710.04–13.24
    When necessary0.2333.770.43–33.38
    Never
Voluntary service0.3080.660.29–1.46
Vaccination0.4201.520.55–4.19
TMD symptoms
    No symptoms of TMD
    Symptoms of TMD without pain0.3591.740.53–5.70
    Symptoms of TMD with pain<0.001*15.014.48–50.250.012*7.351.55–34.81
Tooth loss0.042*2.261.03–4.970.009*4.481.45–13.80
Sleep disorder0.005*4.031.52–10.730.007*5.131.55–16.98
Tinnitus0.005*3.351.44–7.790.2052.160.66–7.06
Relatively close contacts<0.001*11.213.19–39.490.001*12.942.98–56.15

Factors associated with elevated depression.

*

, P < 0.05 was considered significant.

In addition, drinking (B: −2.584, P = 0.013) and never going to the dental clinic (B: −3.675, P = 0.024) were relevant to better oral related quality of life, while TMD without pain (B: 2.797, P = 0.008), TMD-related pain (B: 12.079, P < 0.001), tooth loss (B: 2.546, P = 0.006), sleep disorders (B: 2.598, P = 0.003) were independent risk factors for impaired OHRQoL (Table 5).

Table 5

VariableBStd. errorBeta (standardized)tP95%CI for B
Age
    20–30
    30–400.2421.8440.0150.1310.896−3.390–3.873
    40–50−0.2772.144−0.013−0.1290.897−4.500–3.945
    50–600.5712.0700.0300.2760.7833.506–4.648
    60–70−1.0762.382−0.045−0.4520.652−5.768–3.616
Gender
    Male
    Female0.1020.8520.0060.1200.904−1.575–1.780
Occupation
    State-owned units0.4180.5990.0570.6980.486−0.762–1.599
    Private units−0.1000.974−0.006−0.1030.918−2.018–1.818
    Freelance work0.1021.4350.0060.0710.943−2.725–2.929
    Retired
Education level
    Elementary−0.0351.675−0.002−0.0210.983−3.334–3.263
    Middle school1.2031.8980.0630.6340.527−2.536–4.941
    Bachelor or above
Marital status
    Married
    Single0.8771.3180.0430.6650.506−1.719–3.473
    Divorced2.5761.7720.0811.4540.147−0.914–6.066
Smoking1.1291.3110.0480.8610.390−1.454–3.712
Drinking−2.5841.034−0.136−2.4980.013*−4.620–(−0.547)
Socio-economic status
    Very low0.3850.5880.0500.6540.514−0.774–1.544
    Low−1.0841.171−0.065−0.9250.356−3.391–1.224
    Middle1.2141.0720.0721.1320.259−0.899–3.326
    High
Frequency of going to the dental clinics
    Regular check0.9460.6880.0931.3760.170−0.408–2.301
    Seldom−0.4621.322−0.020−0.3490.727−3.066–2.142
    When necessary
    Never−3.6751.616−0.142−2.2750.024*−6.857–(−0.493)
Voluntary service−0.9330.924−0.060−1.0100.314−2.753–0.887
Vaccination0.0041.1060.0000.0040.997−2.174–2.183
TMD symptoms
    No symptoms of TMD
    Symptoms of TMD without pain2.7971.0510.1422.6600.008*0.726–4.868
Symptoms of TMD with pain12.0791.7320.4086.976<0.001*8.669–15.490
Tooth loss2.5460.9180.1542.7730.006*0.738–4.355
Sleep disorder2.5980.8810.1692.9490.003*0.863–4.333
Tinnitus1.2610.9850.0781.2790.202−0.680–3.201
Relatively close contacts0.1680.8320.0110.2020.840−1.470–1.806

Factors associated with OHRQoL.

*

, P < 0.05 was considered significant.

In order to assess the impact of these variables to the occurrence of anxiety and depression, logistic regression analyses were performed. The multivariant analysis showed that sleep disorder (OR: 3.468, P < 0.001) and relatively close contacts (OR: 6.859, P < 0.001) were independent risk factors for the occurrence of anxiety, and 30–40 years old (OR: 6.073, P = 0.009), 50–60 years old (OR: 7.857, P = 0.005), tooth loss (OR: 1.958, P = 0.036), divorced status (OR: 6.155, P = 0.012), tinnitus (OR: 2.083, P = 0.027) and relatively close contacts (OR: 3.182, P < 0.001) were verified as risk factors for increasing the occurrence of depression. Male (OR: 0.541, P = 0.049) decreased the occurrence of depression (Tables 6, 7).

Table 6

Unitivariable analysisMultivariable analysis
POR95%CIPOR95%CI
Gender (male)0.033*0.5820.354–0.9570.0640.5460.288–1.036
Age
    20–30
    30–40<0.001*4.8592.038–11.5880.0613.7380.94–14.869
    40–500.025*3.1311.158–8.4650.1692.9970.627–14.322
    50–600.009*3.51.368–8.9540.1872.6590.622–11.367
    60–700.3661.6480.558–4.863
Marital status
    Married
    Single0.027*0.4720.242–0.9200.710.8250.299–2.278
    Divorced0.7581.1680.434–3.143
Occupation
    State-owned units
    Private units0.40.770.419–1.415
    Freelance work0.0930.5650.291–1.1
    Retired0.5320.7920.381–1.646
Education level
    Elementary 0
    Middle school0.9450.9310.122–7.081
    Bachelor or above0.8620.8390.116–6.065
Socio-economic status
    Very low
    Low0.1841.8750.742–4.737
    Middle0.0972.2020.868–5.59
    High0.019*3.0131.197–7.5850.0573.6230.964–13.625
Smoking0.1180.5430.252–1.168
Drinking0.4860.8110.45–1.461
Frequency of going to the dental clinics
    Regular check
    Seldom0.7460.8430.3–2.372
    When necessary0.3691.450.645–3.261
    Never0.3511.6640.571–4.853
Voluntary service0.4641.1950.742–1.926
Vaccination0.1720.6390.336–1.214
TMD symptoms
    No symptoms of TMD
    Symptoms of TMD without pain0.015*2.161.158–4.030.1911.7010.768–3.767
    Symptoms of TMD with pain0.002*6.0491.953–18.7360.2452.3140.563–9.51
Tooth loss0.023*1.8121.085–3.0250.4690.7770.393–1.537
Sleep disorder<0.001*4.9572.964–8.29<0.001*3.4681.83–6.574
Tinnitus0.002*2.1881.323–3.6170.9441.0260.504–2.088
Relatively close contacts<0.001*6.1983.671–10.464<0.001*6.8593.585–13.121

Factors of the occurrence of anxiety.

*

, P < 0.05 was considered significant.

Table 7

Unitivariable analysisMultivariable analysis
POR95% CIPOR95% CI
Gender (male)0.009*0.5050.303–0.8410.049*0.5410.293–0.999
Age
    20–30
    30–40<0.001*8.8732.945–26.7350.009*6.0731.559–23.662
    40–500.0523.4140.991–11.758
    50–60<0.001*12.1963.805–39.0910.005*7.8571.848–33.415
    60–700.043*3.751.044–13.4720.3762.0350.422–9.807
Marital status
    Married
    Single0.011*0.3880.188–0.8010.2190.5470.29–1.43
    Divorced0.006*6.0871.699–21.8090.012*6.1551.503–25.208
Occupation
    State-owned units
    Private units0.7480.9040.49–1.668
    Freelance work0.1740.6250.318–1.23
    Retired0.6761.1690.562–2.43
Education level
    Elementary 0
    Middle school1.0001.0000.131–7.605
    Bachelor or above0.6910.6690.093–4.841
Socio-economic status
    Very low
    Low0.5750.780.327–1.861
    Middle0.8951.0610.444–2.532
    High0.8181.1060.468–2.616
Smoking0.9821.0090.483–2.105
Drinking0.2220.6850.374–1.256
Frequency of going to the dental clinics
    Regular check
    Seldom0.2450.5450.196–1.515
    When necessary0.5620.7900.357–1.75
    Never0.1270.4210.139–1.277
Voluntary service0.3591.2530.774–2.027
Vaccination0.05*0.5260.276–1.0010.1260.5430.249–1.188
TMD symptoms
    No symptoms of TMD
    Symptoms of TMD without pain0.0750.5480.282–1.062
    Symptoms of TMD with pain0.0682.4410.935–6.372
Tooth loss<0.001*2.6621.581–4.480.036*1.9581.046–3.664
Sleep disorder0.002*2.1571.324–3.5160.9011.0410.557–1.945
Tinnitus<0.001*3.4992.088–5.8640.027*2.0831.089–3.984
Relatively close contacts<0.001*3.422.076–5.634<0.001*3.1821.754–5.77

Factors of the occurrence of depression.

*

, P < 0.05 was considered significant.

Discussion

Our findings showed that during the city-wide lockdown caused by SARS-CoV-2, TMD and tooth loss significantly altered psychological stress and OHRQoL. When confronting the stress of COVID-19, people had to change their daily life and behavior, particularly social relationships, which can affect health in varieties of aspects, including mental and physical risks (35). In the field of dentistry, previous studies showed that the pandemic's influence on psychological factors may increase risks of developing TMD symptoms and certain oral diseases, such as bruxism and OFP (25, 36, 37). For instance, a study conducted during the pandemic in Israeli and Polish indicated that COVID-19-related mental disorders led to the intensification of bruxism and TMD symptoms, and consequently OFP increased (38). Gender differences has been proven to be an influential factor contributed to such processes: the anxiety and stress caused by COVID-19 participate in deteriorating stomatognathic diseases, and women were generally more influential than men (36, 39). The cross-sectional study from Wuhan lockdown showed a significantly higher impact of COVID-related stress in TMD patients in comparison to orthodontic patients and control population (40). A prospective study in Italy revealed that as compare with acute/subacute TMD patients, chronic TMD patients were more likely to suffer from increased facial pain severity and COVID-19-related stress (41). However, whether dental problems such as TMD and tooth loss may aggravate psychological stress and deteriorate OHRQoL during COVID-19 lockdown in China was rarely reported before. We attempted to identify potential risk factors to predict psychological disorders and the impaired sense of wellbeing under the stressful event. The results provide data supports to improve the manner of treatments and optimize management for people with dental problems. Additionally, our findings are complementary and reinforce the influence of the bidirectional relationship between psychosocial and physical factors in dentistry.

According to our questionnaire-based analysis, our findings demonstrated that TMD-related pain was significantly correlated with increased psychological stress. Of the 71 subjects who reported TMD symptoms, 20 (28.19%) suffered from painful TMD symptoms, which was found to be responsible for the development of more severe anxiety and depression. There were previous studies showing that chronic pain increases the severity of anxiety, as well as depression (42, 43). Although we didn't investigate the specific reason behind elevated stress, one important factor that could not be ignored is the intense confinement under the context of lockdown, which may exacerbate feelings of loneliness. Therefore, we can infer that “home isolation” could be considered as a critic trigger, which was previously confirmed in another study (44).

Our study revealed that TMD symptoms significantly decreased OHRQoL of the volunteers, suggesting that perception of happiness was impaired by TMD symptoms. Our findings could partially explain why non-steroidal anti-inflammatory drugs (NSAIDs) and selective serotonin reuptake inhibitors (SSRIs) could effectively improve the OHRQoL of TMD patients (45). Thus, it is reasonable to speculate that NSAIDs and SSRIs may be considered to relieve the decline of OHRQoL during the pandemic, especially in those with prominent TMD symptoms.

We discovered that the score of anxiety, depression and oral quality in the group with tooth loss were remarkably higher than those without tooth loss. This phenomenon was in consistence with other investigations, but might be more serious under that situation, which could be, at least in part, attributed to the closure of the dental clinics (46, 47).

Lower economic status and educational level were also identified as important risk factors for predicting the severity of psychological disorders during the lockdown. This finding was in accordance with previous studies, which have linked long-term stress including financial or educational problems to the increased stress (43, 48). One possible explanation for this phenomenon is the limited understanding of the SARS-CoV-2, which can be considered as a direct trigger for psychological stress.

It was widely acknowledged that sleep problem is a crucial factor in emotional burden. As an important health indicator, sleep quality may help strengthen the immune system against infection and facilitate in the regulation of behavior and emotion (49). Previous studies demonstrated that global stressor events (e.g., global pandemic, wars) were critical factors for sleep and psychological disorders (50). In this study, we also verified the negative impact of sleep disorders on psychological distress and OHRQoL, indicating that sleep quality could be a potent target for the management of dental patients during lockdown. Of note, people who never go dental have lower oral quality scores than other groups. This sounds strange but is actually reasonable, because those who never go dental might be quite satisfied with their oral health, which was reported in previous literatures (51, 52).

In the present study, no individuals were diagnosed with COVID-19, but 123 (44.40%) were considered as relatively close contacts and strongly associated with anxiety and depression. Under that situation, people were under the almost complete lockdown and all non-emergency medical and dental treatments were suspended. Most public places such as shops, restaurants were closes. Personal contact with family members and/or friends who are not cohabiting in the same household is prohibited. For the confirmed cases and their closest contacts, medical isolation was conducted, which means separation in isolation wards, nuresd by medical staff. Importantly, the relatively close contacts who contacted of any confirmed cases relatively closely or was familiar with confirmed case, faced much higher risk and more fear of being contaminated by the virus than the general population. Based on this, it is not surprising that relatively close contacts presented higher levels of anxiety and depression. Our findings suggest the importance of timely psychological counseling for reducing the psychological pressure of the relatively close contacts. It's encouraging that online intervention for TMD or psychological problems can be useful at least at its initial stage in times of isolations when face-to-face consultation is prohibited during COVID-19 (25). Further investigation is obviously needed to confirm the role of online intervention during COVID-19 lockdown in more detail.

Our findings should be considered with caution given some limitations of the study. Firstly, the relatively small sample size may have influenced results. Secondly, this study was conducted in one center in one country, which reduces the external validity and the generalizability of the results. In addition, Since, the questionnaires were self-reported, subjectivity is a factor that cannot be ignored when translating these findings into clinical practice. In some cases, the extent of anxiety/depression may be overstated or underestimated, which lead to the severity of the illness may be inaccurate. Hence, these factors should be taken into consideration when using the results of our study. Despite these limitations, it is worth noting that the current study for the first time to investigate the impacts of TMD symptoms and tooth loss on the COVID-19 lockdown related anxiety, depression and OHRQoL.

The results remind us that as oral health professionals, our work shouldn't be limited to just the oral cavity, but the whole person. When treating patients with TMD or tooth loss, additional attention should be paid to their psychological status, so as to support their oral health as well as the integral ability to perform activities of daily living. Further prospective longitudinal studies are necessary to validate our findings, thus extending the clinical application of the current study.

Conclusion

This study highlights COVD-19 pandemic, especially the lockdown followed have significant adverse impacts on psychological states and OHRQoL in people with TMD symptoms. Those with TMD-related pain, tooth loss and sleep disorders were more prone to experience worse psychological stress. Individualized management such as psychological counseling should be promoted to maintain control of mental health and OHRQoL under the stressful event.

Funding

This work was supported in part by grant from National Natural Science Foundation of China (No. 31800675 to SH, the Postdoctoral Science Foundation in Jiangsu Province (No. 2018K263C to SH), and 2021 Yangzhou Policy Guidance Plan (Soft Science Research) Project (No.YZ2021231 to XJ).

Publisher's Note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Statements

Data availability statement

The original contributions presented in the study are included in the article/supplementary material, further inquiries can be directed to the corresponding authors.

Ethics statement

This study was approved by the Institutional Review Board and Ethics Committee of Clinical Traditional Chinese Medicine College of Yangzhou University (REC ref 2021-29). The patients/participants provided their written informed consent to participate in this study. Written informed consent was obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article.

Author contributions

SW, SH, XJ, and YS carried out the studies, participated in the experimental design and statistical analysis, and drafted the manuscript. All authors read and approved the final manuscript.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

References

  • 1.

    ScrivaniSJKeithDAKabanLB. Temporomandibular disorders. N Engl J Med. (2008) 359:2693705. 10.1056/NEJMra0802472

  • 2.

    MałgorzataPMałgorzataKMKarolinaCGalaA. Diagnostic of temporomandibular disorders and other facial pain conditions-narrative review and personal experience. Medicina. (2020) 56, 472. 10.3390/medicina56090472

  • 3.

    LimPFSmithSBhalangKSladeGDMaixnerW. Development of temporomandibular disorders is associated with greater bodily pain experience. Clin J Pain. (2010) 26:11620. 10.1097/AJP.0b013e3181c507ef

  • 4.

    XieCLinMYangHRenA. Prevalence of temporomandibular disorders and its clinical signs in Chinese students, 1979-2017: a systematic review and meta-analysis. Oral Dis. (2019) 25:1697706. 10.1111/odi.13016

  • 5.

    ListTJensenRH. Temporomandibular disorders: old ideas and new concepts. Cephalalgia. (2017) 37:692704. 10.1177/0333102416686302

  • 6.

    TayKJYapAUWongJCMTanKBCAllenPF. Associations between symptoms of temporomandibular disorders, quality of life and psychological states in Asian Military Personnel. J Oral Rehabil. (2019) 46:3309. 10.1111/joor.12751

  • 7.

    FillingimRBOhrbachRGreenspanJDKnottCDiatchenkoLDubnerRet al. Psychological factors associated with development of TMD: the OPPERA prospective cohort study. J Pain. (2013) 14(12 Suppl):T7590. 10.1016/j.jpain.2013.06.009

  • 8.

    SuNLobbezooFvan WijkAvan der HeijdenGJVisscherCM. Associations of pain intensity and pain-related disability with psychological and socio-demographic factors in patients with temporomandibular disorders: a cross-sectional study at a specialised dental clinic. J Oral Rehabil. (2017) 44:18796. 10.1111/joor.12479

  • 9.

    BoscatoNAlmeidaRCKollerCDPrestaAAGoettemsML. Influence of anxiety on temporomandibular disorders–an epidemiological survey with elders and adults in Southern Brazil. J Oral Rehabil. (2013) 40:6439. 10.1111/joor.12076

  • 10.

    De La Torre CanalesGCâmara-SouzaMBMuñoz LoraVRMGuarda-NardiniLContiPCRRodrigues GarciaRMet al. Prevalence of psychosocial impairment in temporomandibular disorder patients: a systematic review. J Oral Rehabil. (2018) 45:8819. 10.1111/joor.12685

  • 11.

    QuartanaPJBuenaverLFEdwardsRRKlickBHaythornthwaiteJASmithMT. Pain catastrophizing and salivary cortisol responses to laboratory pain testing in temporomandibular disorder and healthy participants. J Pain. (2010) 11:18694. 10.1016/j.jpain.2009.07.008

  • 12.

    Al-KhotaniAMeishaDEAl SayeghSHedenberg-MagnussonBErnbergMChristidisN. The association between psychological symptoms and self-reported temporomandibular disorders pain symptoms in children and adolescents. Front Oral Health. (2021) 2:675709. 10.3389/froh.2021.675709

  • 13.

    HaagDGPeresKGBalasubramanianMBrennanDS. Oral conditions and health-related quality of life: a systematic review. J Dent Res. (2017) 96:86474. 10.1177/0022034517709737

  • 14.

    OkoroCAStrineTWEkePIDhingraSSBalluzLS. The association between depression and anxiety and use of oral health services and tooth loss. Community Dent Oral Epidemiol. (2012) 40:13444. 10.1111/j.1600-0528.2011.00637.x

  • 15.

    ThomasonJMHeydeckeGFeineJSEllisJS. How do patients perceive the benefit of reconstructive dentistry with regard to oral health-related quality of life and patient satisfaction? A systematic review. Clin Oral Implants Res. (2007) 18(Suppl. 3):16888. 10.1111/j.1600-0501.2007.01461.x

  • 16.

    HarveyWTCarabelliAMJacksonBGuptaRKThomsonECHarrisonEMet al. SARS-CoV-2 variants, spike mutations and immune escape. Nat Rev Microbiol. (2021) 19:40924. 10.1038/s41579-021-00573-0

  • 17.

    VaidyanathanG. Coronavirus variants are spreading in India - what scientists know so far. Nature. (2021) 593:3212. 10.1038/d41586-021-01274-7

  • 18.

    WangPNairMSLiuLIketaniSLuoYGuoYet al. Antibody resistance of SARS-CoV-2 variants B. 1351 and B117. Nature. (2021) 593:1305. 10.1038/s41586-021-03398-2

  • 19.

    DongLBoueyJ. Public mental health crisis during COVID-19 pandemic, China. Emerg Infect Dis. (2020) 26:16168. 10.3201/eid2607.200407

  • 20.

    KimHHJungJH. Social isolation and psychological distress during the COVID-19 pandemic: a cross-national analysis. Gerontologist. (2021) 61:10313. 10.1093/geront/gnaa168

  • 21.

    WuMShenLWangQLiuLLuSJinJet al. Anxiety and depression prevalence and risk factors among patients with cardiovascular diseases in post-COVID-19 China. Front Public Health. (2021) 9:758874. 10.3389/fpubh.2021.758874

  • 22.

    KuangYShenMWangQXiaoYLvCLuoYet al. Association of outdoor activity restriction and income loss with patient-reported outcomes of psoriasis during the COVID-19 pandemic: a web-based survey. J Am Acad Dermatol. (2020) 83:6702. 10.1016/j.jaad.2020.05.018

  • 23.

    QuekSXZLooEXLDemutskaAChuaCEKewGSWongSet al. Impact of the coronavirus disease 2019 pandemic on irritable bowel syndrome. J Gastroenterol Hepatol. (2021) 36:218797. 10.1111/jgh.15466

  • 24.

    RossiRSocciVTaleviDMensiSNioluCPacittiFet al. COVID-19 pandemic and lockdown measures impact on mental health among the general population in Italy. Front Psychiatry. (2020) 11:790. 10.3389/fpsyt.2020.00790

  • 25.

    Emodi-PerlmanAEliI. One year into the COVID-19 pandemic - temporomandibular disorders and bruxism: what we have learned and what we can do to improve our manner of treatment. Dent Med Probl. (2021) 58:2158. 10.17219/dmp/132896

  • 26.

    PengXXuXLiYChengLZhouXRenB. Transmission routes of 2019-nCoV and controls in dental practice. Int J Oral Sci. (2020) 12:9. 10.1038/s41368-020-0075-9

  • 27.

    TangSMaoYJonesRMTanQJiJSLiNet al. Aerosol transmission of SARS-CoV-2? Evidence, prevention and control. Environ Int. (2020) 144:106039. 10.1016/j.envint.2020.106039

  • 28.

    JohanssonMAQuandelacyTMKadaSPrasadPVSteeleMBrooksJTet al. SARS-CoV-2 Transmission from people without COVID-19 symptoms. JAMA Net Open. (2021) 4:e2035057. 10.1001/jamanetworkopen.2020.35057

  • 29.

    PeduzziPConcatoJKemperEHolfordTRFeinsteinAR. A simulation study of the number of events per variable in logistic regression analysis. J Clin Epidemiol. (1996) 49:13739. 10.1016/S0895-4356(96)00236-3

  • 30.

    ConcatoJPeduzziPHolfordTRFeinsteinAR. Importance of events per independent variable in proportional hazards analysis. I Background, goals, and general strategy. J Clin Epidemiol. (1995) 48:1495501. 10.1016/0895-4356(95)00510-2

  • 31.

    SchiffmanEOhrbachRTrueloveELookJAndersonGGouletJPet al. Diagnostic criteria for temporomandibular disorders (DC/TMD) for clinical and research applications: recommendations of the international RDC/TMD consortium network* and orofacial pain special interest group†. J Oral Facial Pain Headache. (2014) 28:627. 10.11607/jop.1151

  • 32.

    SpitzerRLKroenkeKWilliamsJBWLöweB. A brief measure for assessing generalized anxiety disorder: the GAD-7. Arch Intern Med. (2006) 166:10927. 10.1001/archinte.166.10.1092

  • 33.

    KroenkeKSpitzerRLWilliamsJB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med. (2001) 16:60613. 10.1046/j.1525-1497.2001.016009606.x

  • 34.

    El OstaNTubert-JeanninSHennequinMBou Abboud NaamanNEl OstaLGeahchanN. Comparison of the OHIP-14 and GOHAI as measures of oral health among elderly in Lebanon. Health Qual Life Outcomes. (2012) 10:131. 10.1186/1477-7525-10-131

  • 35.

    UmbersonDMontezJK. Social relationships and health: a flashpoint for health policy. J Health Soc Behav. (2010) 51(Suppl):S5466. 10.1177/0022146510383501

  • 36.

    SakiMShadmanpourMNajafiHZ. Are individuals with orofacial pain more prone to psychological distress during the COVID-19 pandemic?Dent Med Probl. (2021) 58:1725. 10.17219/dmp/131683

  • 37.

    ColonnaAGuarda-NardiniLFerrariMManfrediniD. COVID-19 pandemic and the psyche, bruxism, temporomandibular disorders triangle. Cranio. (2021). 10.1080/08869634.2021.1989768. [Epub ahead of print].

  • 38.

    Emodi-PerlmanAEliISmardzJUzielNWieckiewiczGGilonEet al. Temporomandibular disorders and bruxism outbreak as a possible factor of orofacial pain worsening during the COVID-19 pandemic-concomitant research in two countries. J Clin Med. (2020) 9:3250 10.3390/jcm9103250

  • 39.

    DE CaxiasFPAthaydeFRFJanuzziMSPinheiroLVTurcioKHL. Impact event and orofacial pain amid the COVID-19 pandemic in Brazil: a cross-sectional epidemiological study. J Appl Oral Sci. (2021) 29:e20210122. 10.1590/1678-7757-2021-0122

  • 40.

    WuYXiongXFangXSunWYiYLiuJet al. Psychological status of TMD patients, orthodontic patients and the general population during the COVID-19 pandemic. Psychol Health Med. (2021) 26:6274. 10.1080/13548506.2020.1858489

  • 41.

    AsquiniGBianchiAEBorromeoGLocatelliMFallaD. The impact of Covid-19-related distress on general health, oral behaviour, psychosocial features, disability and pain intensity in a cohort of Italian patients with temporomandibular disorders. PLoS ONE. (2021) 16:e0245999. 10.1371/journal.pone.0245999

  • 42.

    De LeeuwRBertoliESchmidtJECarlsonCR. Prevalence of traumatic stressors in patients with temporomandibular disorders. J Oral Maxillofac Surg. (2005) 63:4250. 10.1016/j.joms.2004.04.027

  • 43.

    AkhterRHassan NM AidaJKanehiraTZamanKUMoritaM. Association between experience of stressful life events and muscle-related temporomandibular disorders in patients seeking free treatment in a dental hospital. Eur J Med Res. (2007) 12:53540.

  • 44.

    SaccomannoSBernabeiMScoppaFPirinoAMastrapasquaRViscoMA. Coronavirus lockdown as a major life stressor: does it affect TMD symptoms?Int J Environ Res Public Health. (2020) 17:8907. 10.3390/ijerph17238907

  • 45.

    FischoffDSpivakovskyS. Are pharmacological treatments for oro-facial pain effective?Evid Based Dent. (2018) 19:289. 10.1038/sj.ebd.6401294

  • 46.

    Galindo-MorenoPLopez-ChaichioLPadial-MolinaMAvila-OrtizGO'ValleFRavidaAet al. The impact of tooth loss on cognitive function. Clin Oral Investig. (2021). 10.1007/s00784-021-04318-4

  • 47.

    KiselySSawyerESiskindDLallooR. The oral health of people with anxiety and depressive disorders - a systematic review and meta-analysis. J Affect Disord. (2016) 200:11932. 10.1016/j.jad.2016.04.040

  • 48.

    PallegamaRWRanasingheAWWeerasingheVSSitheequeMA. Anxiety and personality traits in patients with muscle related temporomandibular disorders. J Oral Rehabil. (2005) 32:7017. 10.1111/j.1365-2842.2005.01503.x

  • 49.

    SimonEBOrenNSharonHKirschnerAGoldwayNOkon-SingerHet al. Losing neutrality: the neural basis of impaired emotional control without sleep. J Neurosci. (2015) 35:13194205. 10.1523/JNEUROSCI.1314-15.2015

  • 50.

    UhacITaribaPKovacZSimonić-KocijanSLajnertVMesićVFet al. Masticatory muscle and temporomandibular joint pain in Croatian war veterans with posttraumatic stress disorder. Coll Antropol. (2011) 35:11616.

  • 51.

    LockerDGibsonB. Discrepancies between self-ratings of and satisfaction with oral health in two older adult populations. Community Dent Oral Epidemiol. (2005) 33:2808. 10.1111/j.1600-0528.2005.00209.x

  • 52.

    MatthewsDCBrillantMGClovisJBMcNallyMEFiliaggiMJKotzerRDet al. Assessing the oral health of an ageing population: methods, challenges and predictors of survey participation. Gerodontology. (2012) 29:e65666. 10.1111/j.1741-2358.2011.00540.x

Summary

Keywords

COVID-19, TMD symptoms, tooth loss, mental health, Oral Health-Related Quality of Life (OHRQoL), lockdown

Citation

Weng S, Hou S, Jiao X and Sun Y (2022) Adverse Impacts of Temporomandibular Disorders Symptoms and Tooth Loss on Psychological States and Oral Health-Related Quality of Life During the COVID-19 Pandemic Lockdown. Front. Public Health 10:899582. doi: 10.3389/fpubh.2022.899582

Received

18 March 2022

Accepted

16 June 2022

Published

08 July 2022

Volume

10 - 2022

Edited by

Mieszko Wieckiewicz, Wroclaw Medical University, Poland

Reviewed by

Antonino Maniaci, University of Catania, Italy; Zeinab A. Kasemy, University of Menoufia, Egypt

Updates

Copyright

*Correspondence: Yun Sun Xiuping Jiao Sicong Hou

This article was submitted to Occupational Health and Safety, a section of the journal Frontiers in Public Health

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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