Dental caries is one of the most common preventable childhood diseases, and the most common chronic disease for people worldwide. Dental caries affects general health and the quality of life in preschool children . Pain caused by severe caries can cause poor chewing and affected the quantity and variety of food eaten. Also, it can make eating of high sucrose diet more likely that can compromise intake of other nutrients [1, 2]. By 2011, the overall caries prevalence of Taiwanese preschoolers was 79.3%, significantly higher than in European countries and the United States, and higher than the World Health Organization (WHO) 2020 global goals for oral health: “More than 90% of preschool children free of dental caries” .
Since 2000, the number of immigrant women from Southeast Asia has increased rapidly in Taiwan. The majority of immigrant women are Vietnamese (64.7%) and Indonesian (20.5%), followed by Thais, Filipinos, and Cambodians. These women are colloquially called “foreign brides” or “alien brides” because their marriages were arranged by marriage brokers. The aggregate number of Southeast Asian wives in Taiwan was estimated at more than 466,000, or approximately one-third of Taiwanese marriages. One in 12 children were born of a foreign spouse by 2011 .
With the growing number of transnational marriages in Taiwan, health disparities have become a vital public health issue, especially in maternal and child health. Oral health inequalities exist between immigrants and non-immigrants. Previous studies conducted in Europe and the United States highlighted the worsening dental status of immigrant children [5–7]. Among immigrant children aged 4 to 6 years in Taiwan, the caries index was significant higher than in native children (6.05 vs. 3.88) . The risk factors for preschool children with caries experience were found positively associated with parents in lower educational levels, scant parental attention to the child’s tooth-brushing habits, poor parental brushing habits, and higher frequency of sugar intake among parents [5, 9, 10], with parents playing an important role in preschool children’s caries.
Immigrant mothers have difficulty accessing the health care system because of language barriers, cultural conflicts, social and interpersonal isolation, and a lack of support systems . Literature showed that unemployment, inequality and poverty is a root cause to poor health status, especially in developing countries. The social dimension of globalization encompasses security, culture and identity, inclusion or exclusion and the cohesiveness of families and communities that can impact on the health status of individual, family and society. It can also lead to deteriorating nutritional intake and inaccessibility to medical services [12, 13]. Immigrant women in Taiwan were living in households with low family incomes and educations, in contrast to the native group, which has gradually led to inferior medical care for these women and their children . Numerous studies reported that health insurance can increase dental care use and that is a contributing factor in the decision to seek health care services [15, 16]. The Taiwanese National Health Insurance (NHI) program provides universal and comprehensive health insurance with low co-payments for dental care. Dental care insurance has 100% coverage excluding non-health problem procedures including orthodontics, prosthetic and dental implant but scaling . Nevertheless, previous study  showed that immigrant children had lower numbers of dental restoration treatments than did native children, causing further oral health inequalities. The Taiwanese government has recently begun to pay more attention to the health care for these immigrants and provides several gratis services; however, those above services do not involve some essential oral health services. In addition, the services in the Health Care Service Project (HCSP) by the Department of Health only targets at premarital or prenatal women while the HCSP does not directly provide oral health services for preschool children, and ignores the oral health status of preschool children in new immigrant groups.
The 5-year Lay Health Advisor Approach to Promote Oral Health Program (LHA-POHP), promoting the oral health of new immigrant children, was first implemented in the Kaohsiung area in 2011. The LHA’s strategies are feasible and effective for promoting health care, especially among disparate immigrant populations [18, 19]. We therefore used the baseline data of the LHA Program to explain the immigrant-native differences in caries-related knowledge, attitudes, and oral health behaviors.