Objective To explore knowledge and attitudes regarding the links between diabetes and periodontitis of medical and dental healthcare professionals as well as those of people with diabetes.

Design Qualitative interview study.

Participants 4 people with diabetes, four dental professionals, three general practitioners (GPs) with a specialist interest in diabetes, one GP without a specialist interest in diabetes, three diabetic nurse specialists and two consultant diabetologists.

Setting Primary and secondary care in Newcastle upon Tyne.

Methods Interviews were audio recorded and transcribed verbatim. Framework analysis was used iteratively to achieve progressive focusing and to develop conceptual ideas.

Results 3 inter-related themes emerged: (1) uncertain knowledge—a lack of familiarity about the links between periodontitis and diabetes; (2) unworkable knowledge—that even if the links between periodontitis and diabetes were known, it is impossible for anything to be done for patient benefit given the differing systems that medical and dental health professionals work in and (3) isolated knowledge—the perceived division that exists between the medical and dental professions has the potential to negatively impact on advances in diabetes patient care. The patients simply wanted all the healthcare professionals to be giving the same messages consistently and to help them access the (dental) care they need.

Conclusions The research on the links between periodontal disease and diabetes appears to have limited impact on the organisation of diabetes care, and the divisions that exist between the medical and dental professions have the potential to negatively impact on patient care.