Facilitators and Barriers to Oral Health Behaviors among Patients with Stage III and Stage IV Periodontitis: A Qualitative Study Based on the COM-B Model

Background Periodontitis is a chronic inflammatory disease mediated by dental plaque biofilm, which can eventually lead to tooth mobility, displacement, and even loss, severely impairing masticatory function, quality of life, and overall systemic health. This study employed the COM-B (Capability, Opportunity, Motivation-Behavior) model as a theoretical framework to explore the facilitators and barriers to oral health behaviors among patients with stage III and stage IV periodontitis. Methods This study adopted a descriptive qualitative research design. A purposive sampling method was utilized to recruit patients with stage III and stage IV periodontitis from the periodontal outpatient clinic in a stomatology hospital in Hangzhou, China, between December 2025 and January 2026. Face-to-face semi-structured interviews were conducted based on the COM-B framework. Data were analyzed using a thematic analysis approach with NVivo software. The reporting of this study adhered to the​Consolidated Criteria for Reporting Qualitative Research (COREQ) guidelines. Results The study involved interviews with 19 patients with periodontitis, at which point data analysis indicated that theoretical saturation was reached. A total of 25 facilitators and 31 barriers influencing their oral health behaviors were identified. These were systematically organised within the COM-B framework, resulting in the derivation of 11 sub-themes. Patients commonly experience gaps between knowledge and action, alongside structural barriers such as limited time, restricted access to dental services, and insufficient social support. Emotional responses, health beliefs, and long-established habits further influence behavioral adherence. Conclusions This study demonstrates that oral health behaviors among patients with stage III and stage IV periodontitis arise from complex interactions between individual capability, environmental opportunity, and personal motivation. Interventions grounded in the COM-B model may be more effective in facilitating long-term oral health behavior change and periodontal disease management.