In December 2019, the first case of COVID-19 was reported in Wuhan, China. Globally, as of February 2023, there had been more than 756 million cases of COVID-19, including 6.8 million deaths [1]. In Korea, the total number of confirmed cases of COVID-19 is more than 30 million, and the number of deaths is 33 thousand [2].

The main transmission route of COVID-19 is respiratory droplets from infected people, and the government has implemented various policies to prevent the spread of COVID-19, such as wearing masks, washing hands, social distancing, and refraining from going out [3].

COVID-19 is known to cause changes in daily life and affect the use of healthcare services. A review of 21 studies reported decreased accessibility to health services during COVID-19 worldwide [4]. In 22 public hospitals in China, outpatient visits and discharges decreased by 36.3% and 35.8%, respectively, after the COVID-19 outbreak [5]. In a nationwide survey in Korea, 25.8% and 7.6% of participants experienced delays in health screening and non-urgent medical visits, with varying degrees of change depending on their characteristics [6].

COVID-19 has changed the general population’s access to healthcare and reduced the use of medical services. This is also true for dental care. A nationally representative cross-sectional survey of US adults reported that approximately half of the participants reported delays in dental care due to the COVID-19 pandemic during the spring of 2020 [7]. In Canada, patients receiving dental treatment from March to October 2020 decreased by 46% compared to the same period in 2019, but prescriptions increased by 66% overall [8].

The oral cavity is a pathway for the escape and invasion of pathogens of respiratory infectious diseases, such as COVID-19, and wearing a mask is strongly required in daily life and when visiting medical institutions. Owing to the nature of oral care and dental treatment with a high possibility of generating aerosols, there is increased concern regarding the transmission of COVID-19 in dentistry [7]. Oral health plays an important role in nutrition and pronunciation and can reduce an individual’s quality of life [9] and become a risk factor for various chronic diseases [10]. Unmet dental care occurs when oral problems are not treated due to economic burden or geographic accessi-bility.

According to previous studies, people with low monthly incomes and less educated people are more likely to experience unmet dental needs. In addition, current smokers, people with chronic diseases, and people who perceived their subjective oral health status as poor were more likely to have unmet dental care needs [11,12].

Previous studies have been conducted on the current status of unmet dental care and related factors, but studies conducted during the epidemic of new infectious diseases, such as the COVID-19 epidemic, where general medical use is limited and social distancing, and mask-wearing are important, are insufficient. Therefore, we aimed to identify the current status of unmet dental care during the COVID-19 pandemic and analyze the related factors.

1. Data source and study participants

This study used data from the 2021 Korea Community Health Survey (KCHS). The survey has been conducted annually since 2008 to calculate the health statistics at the community level necessary for establishing a national and community health plan. The KCHS surveyed approximately 230,000 adults aged ≥19 years. The sample areas were selected using the probability-proportional systematic sampling method, and the sample households were selected using a systematic sampling method.

The 2021 survey was conducted face-to-face with trained interviewers from August 16 to October 31, 2021. In accordance with the COVID-19 control guidelines, interviewers conducted a COVID-19 test and participated in the survey only if the results were negative. Survey participants wore masks and were provided with COVID-19 educational materials, and interviewers checked the participants’ body temperatures before the survey. The survey consisted of an individual and household survey and included general characteristics, health-related characteristics, and COVID-19-related characteristics. The KCHS protocol was approved by the Institutional Review Board of the Korea Disease Control and Prevention Agency (2016-10-01-P-A).

Of the 229,242 participants, excluding 35,350 who responded that they did not need dental care, one person who refused to respond, and two who did not know, 193,989 were analyzed.

2. Variables

Unmet dental care responded yes to the following question: ‘During the past year, have you ever been unable to go to the dentist when you wanted to?’ The main reasons for unmet dental care consisted of the following nine items: lack of time, mild symptoms, economic reasons, inconvenient transporta-tion, not wanting to wait for a long time at a hospital or clinic, difficulty in making an appointment at a hospital or clinic, fear of receiving treatment due to the COVID-19 epidemic, and other items.

General characteristics included sex, age, household income, educational level, residential area, and marital status. Health-related characteristics included smoking status (current, past, never), alcohol consumption frequency (none, ≤1/month, 2-4/month, ≥5/month), walking exercise (no, yes), hypertension (no, yes), and diabetes (no, yes). Hypertension and diabetes were defined as lifetime physician diagnosis experi-ences. Subjective oral health status (poor, good), chewing discomfort (no, yes), tooth brushing after lunch (no, yes), and tooth brushing before bed (no, yes) were used.

COVID-19-related characteristics included the impact of COVID-19 on daily life, household income change after COVID-19, household expenditure change after COVID-19, the psychological impact of COVID-19 (infection, criticism, and economic damage), and vaccination against COVID-19. The impact of COVID-19 on daily life was assessed using the following question: “If the state of daily life before the COVID-19 epidemic is 100 points and the complete suspension of daily life is 0 points, what is the current state?” A score of 30 points was classified as high, 31-60 points as moderate, and 61-100 points as not applicable (daily life became more active compared to before the COVID-19 epidemic) and was classified as low. Changes in household income after COVID-19 were assessed as unchanged, decreased, or increased with the following question: “Has there been a change in total household income compared to before the COVID-19 epidemic (January 2020)?” Changes in household expenditure after COVID-19 were assessed as unchanged, decreasing, or increasing with the following question: “Compared to before the COVID-19 epidemic (January 2020), has there been a change in essential consumer spending, such as clothing expenses, food and dining expenses, housing expenses, hospital medical expenses, and education.” Psychological effects of COVID-19 were defined as a very yes or yes response to the following questions: infection “I am concerned that I will be infected with COVID-19”; criticism “I am concerned that if I am infected with COVID-19, I will be criticized or harmed by others for that reason”; economic damage “I am concerned that the COVID-19 pandemic will cause economic damage to me and my family (including losing or finding a job).” COVID-19 vaccination was a yes response to “whether you have ever been vaccinated against COVID-19.”

3. Analysis

This study was analyzed using SPSS 27.0, and descriptive analysis was conducted on general, health-related, COVID-19- related, and unmet dental care needs. Chi-square tests were conducted to analyze differences in unmet dental care according to general, health-related, and COVID-19-related charac-teristics. Finally, multiple logistic regression analysis was performed to analyze the factors associated with unmet dental care during the COVID-19 epidemic. The statistical significance level was set at p<0.05.

1. Unmet dental care

Among the participants, 16.8% had unmet dental care needs in the past year. The main reason for unmet dental care was lack of time (33.0%), and 15.1% were unable to visit a dentist due to the COVID-19 epidemic (Table 1).

Table 1 . Unmet dental care

Characteristics	Classification	N=193,989
Unmet dental care	No	161,356 (83.2)
	Yes	32,633 (16.8)
		N=32,633
Main reason of unmet dental care	Don’t have time	10,767 (33.0)
	Economic reasons	5,750 (17.6)
	Symptoms are mild	4,963 (15.2)
	Due to COVID-19 situation	4,939 (15.1)
	Fear of dental treatment	2,647 (8.1)
	Inconvenient transportation	1,333 (4.1)
	Long waiting time	484 (1.5)
	Hard to make an appointment	249 (0.8)
	Others	1,501 (4.6)

Data were expressed as number (%).

2. Unmet dental care according to general and health-related characteristics

The rate of unmet dental care was 15.6% in males and 17.8% in females. According to the age group, the rate of unmet dental care was 16.3% in those aged 19-44, 18.5% in those aged 45-64, and 15.3% in those aged ≥65 years. According to the monthly household income, the unmet dental care rate was 19.3% in those with less than 2 million won, 16.7% in those with 2 million to 3.99 million won, and 15.0% in those with 4 million won or more (Table 2).

Table 2 . Unmet dental care according to general and health-related characteristics

Variable	Division	Total	Unmet dental care	χ2 (p-value)
Sex	Male	87,561 (45.1)	13,680 (15.6)	163.893 (<0.001)
	Female	106,428 (54.9)	18,953 (17.8)
Age (year)	19-44	54,182 (28.0)	8,828 (16.3)	271.444 (<0.001)
	45-64	76,100 (39.2)	14,073 (18.5)
	≥65	63,707 (32.8)	9,732 (15.3)
House income (10,000 per month)	200	59,836 (31.0)	11,541 (19.3)	445.654 (<0.001)
	200-399	55,554 (29.8)	9,270 (16.7)
	≤400	77,760 (40.2)	11,663 (15.0)
Education level	≤Elementary school	40,652 (21.0)	7,503 (18.5)	277.153 (<0.001)
	Middle & high school	77,903 (40.2)	13,745 (17.6)
	≥University	75,326 (38.8)	11,365 (15.1)
Residence	Urban	110,462 (56.9)	17,696 (16.0)	117.959 (<0.001)
	Rural	83,527 (43.1)	14,937 (17.9)
Marital state	With spouse	123,905 (63.9)	19,851 (16.0)	156.655 (<0.001)
	Without spouse	70,021 (36.1)	12,768 (18.2)
Smoking status	Current	30,980 (16.0)	6,452 (20.8)	429.324 (<0.001)
	Past	36,899 (19.0)	5,761 (15.6)
	Never	126,104 (65.0)	20,419 (16.2)
Drinking frequency per month	None	85,453 (44.0)	14,314 (16.8)	91.069 (<0.001)
	≤1	42,029 (21.7)	6,887 (16.4)
	2-4	32,393 (16.7)	5,140 (15.9)
	≥5	34,107 (17.6)	6,290 (18.4)
Walking exercise	Yes	154,506 (79.7)	24,764 (16.0)	346.302 (<0.001)
	No	39,427 (20.3)	7,868 (20.0)
Hypertension	Yes	57,059 (29.4)	9,693 (17.0)	1.604 (0.205)
	No	136,912 (70.6)	22,935 (16.8)
Diabetes	Yes	24,684 (12.7)	4,374 (17.7)	16.325 (<0.001)
	No	169,296 (87.3)	28,256 (16.7)
Subjective oral health	Good	47,678 (24.6)	2,994 (6.3)	5,021.420 (<0.001)
	Bad	146,309 (75.4)	29,639 (20.3)
Chewing difficulty	Yes	42,118 (21.7)	13,038 (31.0)	7,680.683 (<0.001)
	No	151,871 (78.3)	19,595 (12.9)
Tooth brushing after lunch	Yes	127,138 (65.5)	19,623 (15.4)	507.831 (<0.001)
	No	66,833 (34.5)	13,007 (19.5)
Tooth brushing before bed	Yes	176,797 (91.1)	28,890 (16.3)	330.829 (<0.001)
	No	17,188 (8.9)	3,743 (21.8)

Data were expressed as number (%).

According to smoking status, the unmet dental care rate was 20.8% in current smokers, 15.6% in past smokers, and 16.2% in nonsmokers. The rate of unmet dental care was 16.8% in non-drinkers, 16.4% in those who drank less than once a month, 15.9% in those who drank 2-4 times a month, and 18.4% in those who drank more than 5 times a month. The unmet dental care rate was 6.3% in those with good subjective oral health, 20.3% in those with poor subjective oral health, 31.0% in those with chewing discomfort, and 12.9% in those without (Table 2).

3. Unmet dental care according to COVID-19-related characteristics

The unmet dental care rate was 20.3% for those who responded that the impact of COVID-19 on their daily lives was high, 16.4% for those who responded as moderate, and 15.7% for those who responded as low. The unmet dental care rate was 15.6% among those who responded that their household income had not changed since COVID-19, 18.9% among those who responded that it had decreased, and 17.9% among those who responded that it had increased. The unmet dental care rate was 15.6% among those who responded that there was no change in household expenditure after COVID-19, 18.7% among those who responded that it had decreased, and 19.1% among those who responded that it had increased (Table 3).

Table 3 . Unmet dental care according to COVID-19-related characteristics

Variable	Division	Total	Unmet dental care	χ2 (p-value)
Impact of COVID-19 on daily life	High	33,462 (17.3)	6,789 (20.3)	361.377 (<0.001)
	Moderate	86,460 (44.6)	14,207 (16.4)
	Low	73,832 (38.1)	11,602 (15.7)
Changes in household income due to COVID-19	Unchanged	120,711 (62.3)	18,807 (15.6)	354.818 (<0.001)
	Decreased	68,412 (35.3)	12,952 (18.9)
	Increased	4,781 (2.4)	856 (17.9)
Changes in household expenditure due to COVID-19	Unchanged	121,384 (62.6)	18,880 (15.6)	375.365 (<0.001)
	Decreased	28,505 (14.7)	5,323 (18.7)
	Increased	44,041 (22.7)	8,420 (19.1)
Concerns about COVID-19 infection	Yes	124,124 (64.0)	21,171 (17.1)	13.476 (<0.001)
	No	69,855 (36.0)	11,461 (16.4)
Concerns about criticism from the surrounding people due to COVID-19 infection	Yes	141,520 (73.0)	23,967 (16.9)	4.817 (0.028)
	No	52,435 (27.0)	8,660 (16.5)
Concerns about economic damage due to COVID-19	Yes	144,552 (74.5)	25,189 (17.4)	147.583 (<0.001)
	No	49,417 (25.5)	7,441 (15.1)
COVID-19 vaccination	Yes	160,668 (82.8)	25,981 (16.2)	284.050 (<0.001)
	No	33,317 (17.2)	6,652 (20.0)

Data were expressed as number (%).

4. Factors related to unmet dental care

Women (odds ratio [OR]=1.48, 95% confidence interval [CI]: 1.43-1.54), 19-44 years old (OR=1.93, 95% CI: 1.83-2.03), and those with household income <2 million won per month (OR=1.22, 95% CI:1.18-1.27) were more likely to have unmet dental care. Current smokers (OR=1.33, 95% CI: 1.27-1.39) and those who drank more than five times a month (OR=1.12, 95% CI: 1.08-1.17) were significantly more likely to have unmet dental care. People with poor subjective oral health (OR= 2.92, 95% CI: 2.80-3.04) and those with chewing discomfort (OR=2.79, 95% CI: 2.71-2.87) were significantly more likely to have unmet dental care. Unmet dental care was significantly higher in those who responded that the impact of COVID-19 on their daily life was very high (OR=1.21, 95% CI: 1.16-1.25), those whose total income decreased after COVID-19 (OR=1.11, 95% CI: 1.08-1.15), and in those whose household spending increased after COVID-19 (OR=1.22, 95% CI: 1.18-1.26). Moreover, unmet dental care in those with concerns about economic damage due to COVID-19 (OR=1.07, 95% CI: 1.04-1.11) and in those without COVID-19 vaccination experience (OR=1.20, 95% CI: 1.16-1.24) was significantly higher (Table 4).

Table 4 . Factors related to unmet dental care

Variables		OR (95% CI)
Sex (/male)	Female	1.48 (1.43-1.54)
Age (/≥65)	19-44	1.93 (1.83-2.03)
	45-64	1.81 (1.74-1.88)
House income (10,000 per month) (/≥400)	<200	1.22 (1.18-1.27)
	200-399	1.07 (1.04-1.10)
Education level (≥university)	≤Elementary school	0.95 (0.90-1.00)
	Middle & high school	1.00 (0.97-1.03)
Residence (/urban)	Rural	1.06 (1.03-1.09)
Marital state (/with spouse)	Without spouse	1.07 (1.04-1.10)
Smoking status (/never)	Current	1.33 (1.27-1.39)
	Past	1.17 (1.12-1.22)
Drinking frequency per month (/none)	≤1	1.04 (1.01-1.08)
	2-4	1.04 (1.00-1.08)
	≥5	1.12 (1.08-1.17)
Walking exercise (/yes)	No	1.12 (1.09-1.16)
Diabetes (/no)	Yes	0.97 (0.94-1.01)
Subjective oral health (/good)	Bad	2.92 (2.80-3.04)
Chewing difficulty (/no)	Yes	2.79 (2.71-2.87)
Tooth brushing after lunch (/yes)	No	1.20 (1.17-1.23)
Tooth brushing before bed (/yes)	No	1.19 (1.14-1.24)
Impact of COVID-19 on daily life (/low)	High	1.21 (1.16-1.25)
	Moderate	1.00 (0.97-1.02)
Changes in household income due to COVID-19 (/unchanged)	Decreased	1.11 (1.08-1.15)
	Increased	1.09 (1.01-1.18)
Changes in household expenditure due to COVID-19 (/unchanged)	Decreased	1.11 (1.07-1.16)
	Increased	1.22 (1.18-1.26)
Concerns about COVID-19 infection (/no)	Yes	0.99 (0.96-1.02)
Concerns about criticism from the surrounding people due to COVID-19 infection (/no)	Yes	0.96 (0.93-0.99)
Concerns about economic damage due to COVID-19 (/no)	Yes	1.07 (1.04-1.11)
COVID-19 vaccination (/yes)	No	1.20 (1.16-1.24)

CI: confidence interval, OR: odds ratio.

Due to the COVID-19 epidemic, medical institutions have been restricted, as have restrictions on daily life such as social distancing and refraining from going out. In particular, during the epidemic of a new infectious disease that is transmitted through the respiratory tract, wearing a mask is strongly recommended, and dental care may be affected. Therefore, we aimed to identify the current status of unmet dental care during the COVID-19 pandemic and analyze the related factors.

In this study, the unmet dental care rate among all participants was 16.8%, which increased from 14.7% in a study using the 2019 KCHS [13]. This is similar to previous studies that found delayed dental visits or treatment due to the COVID-19 pandemic. In a survey of Spanish adults conducted in March 2020, 30.9% of participants responded that they were afraid to visit a dentist for fear of COVID-19. Furthermore, 43.7% responded that they would not visit the dentist the following year, and fear of COVID-19 was the most common reason [14]. In a survey of parents of children under 17, 36% of respondents perceived that dental clinics pose a greater risk of COVID-19 infection than public places, and the majority would take their children to the dentist only in an emergency [15]. Dental visits may have decreased because of concerns about COVID-19 infection, as masks cannot be worn during dental treatment, and there is a risk of airborne transmission and aerosol generation.

In studies prior to the COVID-19 epidemic, the main reason for unmet dental care was “economic reasons,” followed by “feeling less important than other problems,” “because I couldn’t leave work or school,” and “fear of dental treatment” [16]. However, in this study, the main reason for not receiving dental treatment was “lack of time” at 33.0%, followed by “economic reasons” at 17.6%, “because of mild symptoms” at 15.2%, and “because of the COVID-19 pandemic” at 15.1%. Therefore, many people did not receive dental treatment because of the COVID-19 pandemic.

In this study, COVID-19-related characteristics affected unmet dental care needs. People affected by COVID-19 daily were more likely to have unmet dental needs. The government has implemented a strong social distancing policy to prevent the spread of COVID-19, which may have affected the daily lives of the general population. According to data from the Health Insurance Review and Assessment Service, the number of outpatient treatment cases in Korea in 2020 decreased by 12.6% compared to 2019. Depending on the disease group, respiratory diseases such as “influenza” and “acute bronchitis” showed the greatest decrease. Compared to 2019, the number of cases treated increased by 3.5% for “endocrine, nutritional, and metabolic diseases,” 5.1% for “mental and behavioral disorders,” and 2.0% for “diseases of the circulatory system” [17,18]. In the era of new infectious diseases, the effect on medical use differs depending on the disease group, and it will be necessary to identify the impact on dental treatment, including the use of medical institutions, according to the disease group in the future.

Compared to those with no change in household income or expenditure due to COVID-19, those with changes, such as increases or decreases, were more likely to have unmet dental care. During the COVID-19 pandemic, restrictions on going out, shortening business hours, limiting the number of people in private gatherings, and social distancing have changed income and consumption patterns. This has led to changes in consumer behavior, including overall spending, spending frequency, amount, product categories, and delivery channels [19,20] According to previous studies, socioeconomic status is associated with unmet medical care [21] Unmet medical care was the highest among medical aid beneficiaries compared to those eligible for health insurance [22]. In addition, “economic reasons” were the most common reason for unmet dental care [16], and changes such as a decrease in family income or an increase in expenses due to COVID-19 may have affected the use of dental care.

People with concerns about COVID-19 are more likely to receive unmet dental care. In a previous study using the 2020 KCHS, concerns about the COVID-19 epidemic were high among the general public [23]. In a previous study conducted in May 2020 on adults over 18 in Korea, 43% answered that they hesitated to visit the dentist because of the risk of COVID-19 infection [24]. Therefore, concerns about the infection or transmission of COVID-19 may have had a negative impact on dental visits.

The proportion of unmet dental care was lower among those with a history of COVID-19 vaccination. With the introduction of the COVID-19 vaccine, vaccination has been recommended for the general population in Korea. People must visit medical institutions for vaccination. As of February 2023, 87.6% of the population in Korea completed the first vaccination, and 86.8% completed the second vaccination [25]. In this study, 82.8% had a history of vaccination, and those who visited medical institutions for vaccination would have had fewer unmet medical care needs due to increased access to medical institutions or contact with medical personnel.

Unmet dental care was related not only to COVID-19-related characteristics but also to general and health-related charac-teristics. The proportion of unmet dental care was higher in women than in men. Women were more likely to be at risk of delays in health screening and non-urgent medical visits than men [6], and dental fear, which was associated with the avoidance of dental visits, was higher in women than in men during COVID-19 [26].

Unmet dental care needs were common in patients with poor subjective oral health or chewing discomfort. The main reason for not visiting the dentist was the burden of treatment costs, despite poor oral health and discomfort with chewing [27]. However, if oral health is not properly managed, it may deteriorate, the masticatory function may decrease, and social activities and quality of life may decrease [28]. Therefore, education on the need for regular oral examinations, including dental visits and treatment in case of symptoms, should be provided.

This was a cross-sectional study using the KCHS, and future studies are needed to conduct a prospective study to confirm the trend of change and causal relationships. The KCHS was conducted from August to October of the survey year, and it was difficult to identify the characteristics of the epidemic period of COVID-19 or the impact on unmet dental care depending on the pattern of COVID-19 occurrence.

Our study found that the rate of unmet dental care needs during the COVID-19 pandemic was 16.8%. This was related to changes in daily life due to the COVID-19. This study could serve as evidence for understanding the status of dental care use during epidemics of infectious diseases such as COVID-19 and measures should be taken to increase access to dental care during future epidemics of infectious diseases.

This article is a condensed version of the first author’s master’s thesis from Chosun University.

No potential conflict of interest relevant to this article was reported.