The internet usage rate of the Korean population aged 3 years or older was 91.5% in 2018, with a 1.2% increase compared to the previous year. The differences according to age and gender have decreased significantly, indicating that the majority of people are using the internet [1].

Recently, a large volume of unstructured information on social media has been circulating owing to the proliferation and rapid increase in smartphone and internet use. “Social media” includes Internet-based applications that allow people to share their experiences and opinions and exchange comments online [2]. Data based on the social relations of such social media applications are known as “social big data” [3], and research has been conducted in various fields to collect and analyze the large-scale data generated in real-time to derive countermeasures or predict social changes [4]. Moreover, the universality of social media integrates the functions of rapid acquisition of information and personal communication, while it can also be used to identify public interests and trends by focusing on specific issues, social phenomena, and keywords [5].

The current study was implemented with the idea that the field of public health and dentistry should identify public interests and trends related to oral health and reflect them in the development of oral health projects and planning.

Regarding the formulation of plans for dental health projects in Korea, projects regarding the dental health of pregnant women and infants must be included and should be managed as dental health projects for mothers and infants as per the Mother and Child Health Act [6].

Pregnant women and infants are thus a target segment of the population and are specifically vulnerable to oral health complications. Parents play an important role in the oral health condition of infants and toddlers [7]. This is particularly true of pregnant women because the oral health condition of the mother is closely related to that of the child [8]. In addition, the oral health behaviors of infants and toddlers affect their entire lives. Therefore, the importance of oral health in infants and pregnant women is emphasized by regulations and various public health services [9].

Because infants and toddlers are susceptible to oral diseases and are unable to care for their own oral health, caregivers are required to help them with oral health management, knowledge acquisition, and habit formation [10]. During this period, the role of parents and caregivers is important and should focus on thorough management and prevention of the dental caries [11,12].

Pregnancy gingivitis in pregnant women is very common [13], and periodontal disease during pregnancy can lead to low birth weight, preeclampsia, and preterm delivery [14,15]. Therefore, the oral health of pregnant women and infants is important systemically and must be managed at the clinical and government levels.

The identification of common search keywords and common perceptions regarding oral health using the social media big data mentioned above in mother-and-child subjects may enable us to develop more practical oral health projects and conduct more effective promotional activities. Two examples of social big data analyses are trend analyses of health technologies [16] and network analyses in health informatics [17]. There are also cases in which diseases are predicted by the analysis of search trends [18]. Such analyses of public perceptions are, however, field- and country-specific. So far, there have been no big data analyses in the field of dentistry and dental hygiene in Korea. The existing methods of survey research to understand public perceptions have their limits because it is necessary to analyze social media big data associated with actual public perceptions and not simply base analyses on the oral condition index provided by experts.

In this study, we focused on online child-rearing communities, so-called “mom cafés”, where concerns about childrearing are shared and social learning through interaction is carried out. The trends of mom cafés were analyzed and compared with those of other cafés, including those run by dental clinics, to investigate the two main subjects of mother-and-child oral health, and infants and mothers.

Mom cafés are personally run, online child-rearing communities, which have the “café” format provided by Naver. Members are mainly parents of infants and preschool children as well as prospective parents [19]. Mom cafés are characterized by bidirectional communication regarding pregnancy, childbirth, and child-rearing and are subcategorized into various dashboards. Hence, mom cafés are considered to better reflect the search keywords regarding mother-and-child oral health than any other online communities.

This study investigated the trend in the search keywords regarding the oral health of infants and expectant mothers and analyzed social media big data concerning oral health in so-called mom cafés, whole cafés, and dental cafés belonging to a domestic portal (Naver).

The social network services (SNSs) mainly used in Korea in 2017 were Facebook, Kakao Story, and Instagram, while Naver cafés belonging to the “community” category of social media accounted for 10.7% of SNS use [1].

Among these, mom cafés are an internet space where users who are interested in topics related to pregnant women, parents of infants and toddlers, and children come together grouped by region and interests, to form a community and share information. Therefore, we decided that using these mom cafés in community social media could enable us to understand the interests and perceptions of pregnant women and women with infants more effectively.

First, to confirm the general public’s awareness of and interest in dental health, the frequencies of search results from all cafés, dental clinic/hospital cafés, and mom cafés were examined. Our results showed that the rankings for each keyword differed according to the type of café. The top search keywords for the mom cafés mainly targeting pregnant women appeared to be “oral examination”, “sealant”, and “tooth brushing”.

Dental examinations are preventive activities for the early detection and treatment of oral diseases, and they are administered three times from 18 to 65 months of age in infants and toddlers [20]. Children who have undergone oral examinations later need less medical care than do those who have not, demonstrating the effectiveness of early examinations in reducing pain and medical costs [21]. Our data confirm that awareness of and interest in oral examinations is greater among users of mom cafés compared to users of other cafés.

Dental sealants were first included in the National Health Insurance (NHI) benefits in December 2009 for the first molar in children aged 6–14 years and for the second molar in October 2012. The qualifying age for the benefit has since been continuously expanded to include anyone under the age of 18 years in May 2013 [22]. In addition to oral health examinations for infants and toddlers, dental sealants are used a preventive measure for dental caries in children, and they are of high interest to parents who have young children because they are covered by the NHI. Our findings confirm that parents were actively sharing information on the top three items, namely, “oral examination”, “sealant”, and “tooth brushing” on mom cafés because these are essential for dental care in infants and toddlers.

On the other hand, “periodontal disease” was the most frequent result for keywords used in dental clinic/hospital cafés. Generally, social media sites operated by clinics/hospitals are for specific patients, and their interests differ from those for pregnant women and women with infants. This indicates that the keywords of interest regarding oral health in the general public vary depending on the specific subject and the nature of the community.

Medical consumers receive information about doctors, clinics, and healthcare through social networking web sites, such as blogs run by doctors, online communities, or YouTube, as well as specialized health portal sites. In addition, SNS information provided by medical institutions is regarded as a verified resource, and it influences the formation of a positive and trustworthy image [23].

From 2008 to 2018, the prevalence of periodontal disease in the Korean population aged 19 years or older decreased by 8.7% [24]. However, periodontal disease is the main cause of missing teeth and major oral disease; therefore, thorough oral healthcare is necessary. Accordingly, the search keywords regarding adult oral diseases are ranked at the top in dental cafés.

The results of the analysis of the network of oral health-related keywords for infants and pregnant women showed that the network consisted of keywords related to prevention in infants and toddlers, while those for pregnant women included “periodontal disease” and “oral disease”. As previously mentioned, there was great interest in the preventive treatment and management of infants and toddlers because this is essential for oral care, but “prevention” in pregnant women seemed to be of interest to only a minority, and very little interest was observed for “scaling”.

Oral health education and oral examinations are provided for pregnant women, and Mother and Child Health Pocketbooks are issued to those with infants, according to the Mother and Child Health Act [6]. Various services such as fluoride coating and tooth brushing education are also being provided by community health centers. In particular, it is highly important to implement prevention activities, such as oral health education, for pregnant women. It has been reported that a mother’s oral health knowledge has a greater influence on the oral healthcare of the child than the father’s because the mother spends more time with the child [25].

It has also been reported that the child’s dental caries experience is directly proportional to the mother’s dental caries experience [26]. Therefore, children’s level of oral health may differ according to their mothers’ oral health knowledge and behavior.

This shows that it is necessary to promote awareness and change the perception of oral health examinations, oral health education, and preventive management in pregnant women.

We also analyzed trends in changes in the frequency of the search terms “dental caries”, “dental health”, “scaling”, “tooth brushing”, and “oral examination” according to the search period. We found that the frequency of all keywords increased overall in 2016 and 2017 compared to January 2015. This may be a result of the increased use of the internet, but it also suggests that public awareness of oral health increased.

The frequency of the keyword “dental caries” increased over time on all cafés, especially on the mom cafés. In addition, the word cloud related to dental caries was focused on the treatment of the affected teeth rather than on preventive treatment. Dental caries in infants is an infectious and contagious disease, which affects the surfaces of multiple teeth simultaneously, and its incidence rapidly increases until childhood [27]. According to a survey of the oral health status of children in Korea conducted in 2015, the percentage of childhood dental caries was 62.2% in 2012 and 64.4% in 2015, suggesting that preventative activities related to dental caries should be actively promoted [28,29].

On the other hand, the search term “dental health” was characterized by a significantly higher frequency on all cafés and on dental cafés, compared to mom cafés, while “implants” and “orthodontics” were prominent terms in the word cloud. Implants and orthodontic treatment are tertiary preventative dental treatments that are applied for oral rehabilitation in cases where tooth loss and malocclusion are evident. Therefore, the keyword “dental health” in the public seems to be perceived as treatment-oriented rather than prevention-oriented. The keyword “scaling” showed a sudden increase in frequency on mom cafés and across all cafés in June 2017. This suggests that the frequency of the keyword search increased due to a change in the coverage period for scaling implemented around that time. The keywords “tooth brushing” and “oral examination” were dominant on mom cafés, while their frequencies were very low across cafés of general dental clinics/hospitals, indicating a difference in interests.

To summarize, the present study analyzed dental health-related keywords used on community SNSs that are used mainly by mothers, in comparison to those used by the general public. We found a difference between the interests of the general public and those expressed on the mom cafés. In addition, there was an interest in preventive management, such as oral examinations, dental sealants, and tooth brushing to improve oral health in infants and young children, but it seems there is a need to raise awareness of prevention management among pregnant women. Furthermore, as the perception of dental caries is still focused on treatment rather than prevention, it is necessary to change this perception and provide oral health education for pregnant women and women with infants as well as for the general public. This study was conducted using a single portal site at one time-point; therefore, the results cannot be generalized to all pregnant women and women with infants. The perceptions of the general population need to be further assessed through the analysis of big data obtained from a variety of subject populations.