Dental caries or early childhood caries (ECC) is a childhood common chronic infectious disease (1). The disease of early childhood caries is defined as one or more decayed, missing (resulting from caries), or filled teeth in primary dentition in children aged up to 71 months (2, 3). ECC remains prevalent worldwide, with over 573 million children experiencing dental caries (4). In Hong Kong, over 50% of 5-year-old children experience tooth decay or ECC, with more than 90% of their carious lesions remaining untreated (5). The impact of untreated caries in early childhood is not just pain and infection but more immediate and long-term consequences (6). ECC is a health burden to the family and society, including higher risk of acute and chronic pain, hospitalizations and emergency room visits, delays in growth and development, and diminished quality of life, all of which are costly for society, government, and family (7, 8). Given the high prevalence of untreated ECC reported in Hong Kong and globally, there is an urgent need to prevent this disease (9).

Over the years, several preventive programs have been implemented by the Hong Kong Government to reduce dental caries in children. The School Dental Care Service was launched in the 1980s to provide regular check-ups and treatments for primary school students (10). However, preschool children are not eligible to join this service. Oral health education (OHE) programs, such as Brighter Smiles Play Land, are offered to preschool children by the Oral Health Education Division under the Department of Health. Nevertheless, no preventive or curative treatment is available for preschool children from these programs (11). To date, there is no primary oral health program targeting ECC at the government level. To improve the ECC situation, a comprehensive oral health program called Children Oral Health Program was launched by The University of Hong Kong to provide dental care services to all preschool children in Hong Kong (approximately 160,000 children). This program was funded by a charity organization to provide dental services from 2019 to 2022 initially, and then received extra funding to provide services from 2023 to 2026.

The program offers a comprehensive range of services, including on-site dental check-ups and silver diamine fluoride treatment, individual consultation and oral health education for parents, and oral health education training for teachers. The World Health Organization (WHO) suggests that engaging different stakeholders, including teachers and parents, is of vital importance to manage ECC (12). The online OHE training for teachers in this program consisted of a 90-min lecture followed by a 60-min small group discussion modulated by four trained dentists. Between 2019 and 2022, a total of 68 training sessions were conducted fortnightly, excluding public holidays. The lecture content covered essential topics, including oral health status among preschool children, etiology and risk factors of dental caries, prevention and treatment options for dental caries, other common oral health problems and treatments, and the teacher's role and teaching technique suggestions. In small group discussions, the dentists demonstrated tooth-brushing and flossing techniques, examined the acidity of common beverages, answered questions, and invited teachers to share their experiences and difficulties in providing OHE in preschools. The teachers were encouraged to practice tooth brushing and flossing as well as testing common beverage acidity by themselves. The details about the training curriculum can be found in Supplementary File 1. All kindergarten teachers in Hong Kong were invited to attend this optional training. The aim of the OHE training is to empower teachers with knowledge to recognize childhood oral diseases, enhance their skills in delivering oral health education, and ultimately improve children's oral health.

Numerous studies have reported that the prevalence of ECC is significantly related to socioeconomic factors as well as behavioral factors, such as oral hygiene and dietary practices (13, 14). Teachers are one of the key individuals in reinforcing the oral health message and promoting oral-health-related habits to children. Preschool teachers, namely, early childhood educators, are pivotal in shaping the development paths of young children (15, 16). There are strong, responsive relationships between child and caregiver, including early childhood educators, in facilitating children's communication and health behavior development (17, 18). Teachers contribute to children's educational development and influence their wellbeing with daily routines, including essential oral hygiene habits. They interact with children frequently and act as primary influencers of children's daily behaviors (19). Moreover, they usually act as the primary contact point for parents regarding their child's development and needs, and as an influencer to both child and family health-related practices (20, 21). Equipping them with proper training in oral health has substantial potential in enhancing their ability in promoting good oral hygiene habits among children (18).

It is important to understand the impact of OHE training on kindergarten teachers. We can identify gaps to enhance the training and provide evidence-based updates for the dental professionals and policymakers to plan long-term policy and formulate a comprehensive health promotion strategy. Our experience can be contributed to other school-based health programs worldwide. This study aims to examine kindergarten teachers’ satisfaction with the OHE training and their perceived impact of the training. In addition, the study also collected their comments and suggestions toward the OHE training.

This study had 6,210 kindergarten teachers participating in the training between 2019 and 2022. Of them, 4,882 completed the survey (response rate 78.6%). The findings are summarized below and presented in Table 2 and Figure 2.

This is the first study to evaluate a program-based OHE training for kindergarten teachers in Hong Kong. This territory-wide school-based outreach oral health program is the first of its kind, an eye-catching program benefiting over 100,000 preschool children. Teacher training is an essential part of this program because effective collaboration and engagement with different stakeholders are crucial to the success of oral health promotion (20). The results of this study showed that the OHE training demonstrated a high level of engagement and satisfaction among participants. The training was essential for their teaching in kindergartens and participating teachers generally valued the training and its benefits. They reported that the training helps equip them with more knowledge to recognize children’s oral diseases and to deliver oral health education to children. The training met teachers’ expectations and was recommended to continue in the long term. Moreover, participants raised comments and suggested different key elements that may also act as references for other health programs. They commented that the training is comprehensive and informative, significantly enhancing their knowledge about children's oral health. They appreciated that the rich content covered essential precautions for dental caries and effective dental care methods. Moreover, the professionalism of the training team was highly praised. In general, this OHE training met its goal of empowering preschool teachers.

Participants offered valuable suggestions to enhance the training. They suggested the content of the training should be more realistic and closer resemble daily situations. Some studies suggested that case-based learning using real-life cases helps learners impart relevance and connect the theory to reality (24). In addition, interactive and hands-on activities should be increased because traditional lectures have certain limitations. Interactive tools help to attract people's attention and participation, which may also benefit the implementation of the training (25, 26). Moreover, more resources and support were also considered necessary for the training. People tend to seek more information and practical support after realizing the importance of oral health. Providing educational resources after training, such as PowerPoint documents, notes, and reading materials, are necessary to aid teachers in their ongoing learning and teaching efforts. Educational resources may help people learn about the related topic and post (27). Teaching materials, including tooth models and booklets, are useful tools to facilitate demonstrations of proper dental care techniques. This practical support may help to solve problems and be effective in transferring and applying the skills and behavior learned during training to the teacher's workplace (27, 28). Therefore, this program has undergone significant adjustments in phase II (2023–2026). The teacher training has been revamped to include more real-life cases and various interactive elements such as hand-on activities. The training has been refined, with more focus on children's oral health topics, and expanded to include more content on different treatment option, knowledge of tooth replacement, dental development abnormalities, and the management of dental emergencies. In addition, different teaching and learning materials, such as tooth models and booklets, are offered. The impact of the teacher training in phase II will be evaluated in a future assessment.

The WHO suggested that the school setting provided a unique platform for implementing population-directed oral health interventions (20). Children's participation was increased in a school setting and those who were unable to go to dental clinics could be reached (29). Moreover, school is the place where students develop lifelong health-related behaviors, beliefs, and attitudes, which may help develop good oral health awareness and behaviors (12, 26, 30). Professional training is a major component of updating teachers' knowledge and skills in different categories (31). A key step to establishing collaboration with schools is to provide effective professional preparation for childhood educators. A study conducted in Hong Kong kindergartens indicated that teachers’ understanding of a health program might affect their attitudes toward the implementation of the program in their kindergartens (32). A literature review showed that teacher advocacy for health programs can effectively influence their implementation (33). Therefore, it is important to involve teachers in school-based programs in advance, trigger their interest, and empower them to teach children about oral health in a school setting. Teacher training is crucial to the school-based health program's success and is beneficial to kindergarten children in improving their oral health. The WHO also suggests that both parents and teachers play a crucial role in children's oral health behaviors and attitudes. A literature review revealed that many parents are not adequately trained and informed about managing their children's oral hygiene. The gap in oral health literacy can lead to a range of negative oral health outcomes (34). Therefore, parents’ oral health education is also important (35). It is essential to develop and implement a comprehensive program promoting oral health at school to empower caregivers to manage oral-health-related risk factors among their children.

This study was conducted following the Program Evaluation Standard in Public Health framework from the CDC. To gather evidence from participants, this study adopted closed-ended questions to collect solid results as well as open-ended question to allow participants to express detailed insights and discover unanticipated responses (36, 37). To manage diverse responses from the open-ended questions, a thematic analysis was adopted to discover, interpret, and report patterns and clusters of meanings. Moreover, this study used themes and coding during data analysis to facilitate the process of summarizing key issues and to present the findings in a clear and compelling narrative (36).

However, this study has some limitations. First, the program conducted online OHE training during the COVID-19 epidemic during 2019–2022. This setting may influence participants’ experiences, potentially differing from face-to-face training. Second, participants in this optional training might be influenced by social desirability bias, leading to favorable and positive feedback. Third, the materials and curriculum are not universally recognized and may need to be validated or updated if they are adopted by other countries. Nevertheless, this study helps researchers, project managers, and different stakeholders understand teachers’ views toward school-based oral health education training for teachers and provides different ways of improving the framework, service, and lesson to plan future health programs.

The participating teachers were generally satisfied with the training and agreed that the training achieved its objective of equipping them with knowledge and skills. They expressed positive attitudes toward the training. They agreed that this training was beneficial and suggested that it was implemented regularly, providing suggestions for its content and resources. This study provided evidence on the impact of this program-based oral health education training for kindergarten teachers in Hong Kong.