Dr. Han experienced in research on clinical interventions and public health dentistry, including 40 peer-reviewed articles at high-end dental and public health journals using nationally representing surveys and cohort datasets. His research interests were the interaction of oral health-systemic diseases and the promotion of community oral health as well as oral health equity. In particular, he had been performing research in areas such as the effect of socio-environmental factors on the trend of dental caries, the relationship of the salivary microbiome with oral and systemic diseases, and epidemiological analysis.