With the increase in the number of multicultural families, the number of children born in these families is also increasing; the youth population of general families is gradually decreasing, whereas the number of youths in multicultural families continues to increase, exceeding 100,000 in 2017 [1].

Although adolescence is more important than other periods because physical and emotional changes are evident and youths undergo many changes [2], adolescents from multicultural families often drop out because of cultural adjustment stress, negative school adjustment, and bad school experiences, such as prejudice and bullying among students [3]; these negative events lead to critical psychological problems [4]. Lim et al. [5] reported that mental health issues such as depression and suicidal ideation among adolescents from multicultural families were approximately 10% higher than among adolescents from general families, and the happiness index was lower at 3.06 points among adolescents from multicultural families than among adolescents (3.38 points) from general families [6]. Thus, attention should be paid to the mental health of adolescents from multicultural families.

In addition, poor mental health during adolescence has a negative effect on oral health by increasing the morbidity of oral diseases and risk behaviors of oral health [7,8]. Negative mental health leads to poor eating habits and worsening oral hygiene, and causes various oral diseases such as gum swelling, bad breath, and oral mucosa disease [9]. In particular, adolescents had worse mental and oral health than other age groups [9,10]. Since adolescents from multicultural families have worse mental and oral health than adolescents from general families [10], it seems necessary to identify the relationship between oral health and mental health of adolescents from multicultural families, as management of both oral and mental health was judged necessary. However, most previous studies were conducted on adolescents from general families [11] or investigated stress only in the context of mental health [12], and few studies have been reported on adolescents from multicultural families. As a result, various aspects of mental health have not been addressed.

Adolescents who have correctly formed knowledge, behaviors, and perceptions of oral health can continue into subsequent periods and have good oral health throughout their lives [13]. Hence, adolescence is a critical period for developing the ability to maintain a healthy oral cavity.

Based on the data of the Korea Youth Risk Behavior Web-based Survey, this study aims to develop plans and measures for improving oral health among adolescents from multicultural families by investigating the mental health of adolescents from multicultural families in various ways and determining the relationship between stress, depression and suicidal ideation, and self-perceived oral symptoms.

It has been reported that adolescents from multicultural families have worse mental health than those from general families, and this state of psychological instability can also be a risk factor for oral health [14,15]. Hence, this study identified the relationship between mental health and self-perceived oral symptoms of adolescents among multicultural families.

Adolescents from multicultural families felt the greatest mental health stress; female students were more likely to be stressed, depressed, and have suicidal ideation than male students. This is the same result as derived for the study of adolescents from general families [16,17], which is thought to be because female students experience more negative mental health effects than male students [18]. Further, within the residence category, multicultural youth living with their families were more likely to have suicidal ideation, compared with the youth of general families [19]. It is believed that authoritarian parental education, authoritative parenting attitudes, and family-environmental influences among other factors affect the mental health of multicultural adolescents [20], and measures for mental health management are needed considering that the influence factors applied to adolescents from multicultural families differ from those of general families.

Female adolescents in multicultural families experienced more trauma and pain within the category of self-perceived oral symptoms than did male adolescents, and ulorrhagia was higher within the middle and lower economic classes than among the upper class. This was the same result, as this study covered not only multicultural families but also adolescents from general families [21]. The economic status of adolescents is not related to oral health conditions and incidence of diseases and plays a vital role in predicting their health conditions [21,22]. However, since adolescents in multicultural families experience more unfavorable conditions such as low economic status and a poor environment for oral health than those in general families, more attention should be paid to multicultural adolescents, and oral health education and programs should be provided.

Stress and depression were related to pain in the category of self-perceived oral symptoms, indicating the same results as in Won et al. [23], and suicidal ideation was related to trauma in the category of self-perceived oral symptoms. Such mental health phenomena as stress, depression, and suicidal ideation among adolescents can be considered in relation to the study [24], which showed that they affected oral health behaviors and conditions. Stress, in particular, is reported to be considered in the category of mental health in oral care because many previous studies showed that a higher level of stress was associated with higher incidence of gum swelling, oral mucosa disease, and dental caries, and had negative effects on oral health behavior [25,26]. In addition, the decayed, missing, and filled teeth (DMFT) index was higher among the group with depression experiences than among the group without depression experiences, indicating a worse oral condition [11]. It can be speculated that this was because subjects who had not engaged in good oral care might have experienced various symptoms related to oral diseases, potentially leading to poor mental health [13].

The above results showed that mental health and self-perceived oral symptoms among adolescents from multicultural families were related and showed different self-perceived oral symptoms depending on stress, depression, and suicidal ideation. Therefore, it is necessary to develop a customized oral health plan and management measures considering factors appropriate to the mental health only for adolescents from multicultural families.

This study has a limitation in that causality cannot be explained clearly through a cross-sectional study. However, it is meaningful that Korea Youth Risk Behavior Web-based Survey data that can represent Korean adolescents elucidate the relationship between mental health and self-perceived oral symptoms among adolescents from multicultural families. Based on this study, it is expected that a study using adolescents from general families as a control group or a multifaceted study using various variables, such as oral health factors, will be needed in the future.

Based on the 15th Korea Youth Risk Behavior Web-based Survey (2019), this study investigated the relationship between mental health and self-perceived oral symptoms among adolescents from multicultural families.

1. In the category of mental health according to general characteristics, stress was higher among women and those with lower grades, and depressive experiences and suicidal ideation were higher among women, the middle class, and those living with family.

2. In the category of self-perceived oral symptoms according to general characteristics, trauma and pain were higher among women, and ulorrhagia was the highest among the middle class.

3. Regarding the relationship between mental health and self-perceived oral symptoms, the group with stress suffered pain levels that were 2.09 times higher and ulorrhagia levels that were 1.94 times higher than those without stress. The group with depression experiences suffered pain levels that were 1.52 times higher and ulorrhagia levels that were 1.61 times higher than the group that had not experienced depression. The group with suicidal ideation suffered trauma levels that were 2.40 times higher than the group without suicidal ideation.

The results of this study show that oral health plans and measures for oral health should be prepared according to mental health among adolescents from multicultural families.