Objective: This study examined the factors underlying the sustained intention to participate in oral care for older adults among caregivers and dental hygienists in long-term care facilities, using the capability, opportunity, motivation, and behavior (COM-B) model. Methods: A survey was conducted with 205 participants experienced in providing oral care for older adults in long-term care facilities in the Seoul metropolitan area. Data were analyzed using descriptive statistics, independent t-tests, Pearson’s correlation analysis, and multiple regression analysis. Results: Motivation had the highest mean score, followed by behavior, opportunity, and capability. Dental hygienists demonstrated significantly higher levels of capability, motivation, and sustained intention to participate than caregivers, whereas caregivers showed higher levels of opportunity. Sustained intention to participate was positively correlated with capability, opportunity, and motivation (p<0.001). Motivation (β=0.657), capability (β=0.170), and oral health education experience (β=0.100) were significant predictors, and the model showed an adjusted explanatory power of 59.6%. Conclusions: Motivation was the strongest factor influencing sustained intention to participate. Therefore, practical educational programs tailored to occupational characteristics, continuous educational opportunities, and collaborative support strategies between caregivers and dental hygienists are required to promote sustained participation in oral care for older adults in long-term care facilities.