Case report A case of a 59-year-old female patient who attended with a history of periodontitis, who had been successfully treated and maintained for several years, is described. Following a full periodontal assessment, the patient was diagnosed with 'generalised periodontitis; stage IV; grade C; currently stable'.Conclusion The present case report exemplifies the use of the 2017 classification system in a successfully treated and well-maintained patient whose treatment need is supportive periodontal treatment. It recognises the fact that, by staging and grading, the patient is a high-risk periodontitis patient due to historical disease experience, but also that following successful therapy and maintenance she is currently 'stable' with no need for active periodontal therapy.