Which of the following is an indication for referring patients to a periodontist?

Referring patients to a periodontist is particularly warranted in cases of severe attachment loss, which is defined as loss of the connective tissue and bone supporting the teeth. When attachment loss exceeds 6 mm, it indicates significant periodontal disease that can lead to tooth loss if not managed adequately. Periodontists specialize in diagnosing and treating more complex periodontal issues, particularly those that involve advanced stages of periodontal disease. Their expertise is crucial in creating comprehensive treatment plans that may include surgical options or more intensive nonsurgical therapies to restore health to the periodontal tissues.

In contrast, minor gum inflammation, healthy periodontal conditions, and the need for routine cleanings do not typically require the specialized care of a periodontist. Minor inflammation can often be managed by general dental practitioners, while regular cleanings are part of preventive care that can be effectively handled by general dentists. Healthy periodontal conditions indicate that the patient does not have significant issues requiring referral for specialized treatment. Each of these conditions indicates a lesser need for intervention compared to the severe attachment loss signified in the correct choice.