This observational study will evaluate the accuracy of a self-reported periodontal questionnaire in adults attending screening appointments in Abha, Saudi Arabia. Participants will complete the questionnaire and then undergo a same-visit clinical periodontal examination. The study will compare questionnaire-based results with clinical examination findings to assess diagnostic accuracy and agreement.

This observational, cross-sectional clinical validation study will assess the validity of a self-reported periodontal questionnaire (CDC-AAP self-report items) among adults attending scheduled screening appointments at Asir Specialized Dental Center in Abha, Saudi Arabia. At the screening visit, participants will complete the self-reported questionnaire. During the same visit, trained clinicians will perform a standardized full mouth clinical periodontal examination, which will serve as the reference standard for determining periodontal status and/or periodontal disease categories according to predefined clinical criteria in the study protocol.

The primary objective is to determine how accurately the self-reported questionnaire identifies clinically determined periodontal status. Questionnaire responses and any questionnaire-derived classification will be compared with clinical examination results to estimate diagnostic accuracy (e.g., sensitivity, specificity, and overall accuracy) and to assess agreement between questionnaire-based and clinically based classifications. Additional outcomes may include feasibility measures such as questionnaire completion rates and missing data patterns. Data will be recorded using study identifiers and stored in secure, access-controlled systems to protect confidentiality. Participation does not involve assignment to any treatment; it consists only of completing a questionnaire and undergoing a same-visit periodontal examination.

Inclusion Criteria:

• Age 18 years or older
• Able to provide informed consent
• Able to complete the self-reported periodontal questionnaire
• Willing to undergo a same-visit clinical periodontal examination

Exclusion Criteria:

• Less than ten teeth present
• Any condition that makes periodontal probing unsafe, as judged by the clinician according to local policy
• Unable to complete study procedures or provide informed consent

Participants will be selected from adults scheduled for dental screening appointments at Asir Specialized Dental Center, Abha, Saudi Arabia. Recruitment and all study procedures will take place at the center during the scheduled screening visit.

De-identified, controlled access.

De-identified IPD and supporting documents will be available beginning 12 months after publication of the primary results (or 12 months after study completion if not published) and will remain available for 5 years thereafter.

Access will be provided to qualified researchers who submit a methodologically sound proposal (protocol/analysis plan) and obtain any required ethics approval/exemption. Approved requestors will receive de-identified participant-level data (questionnaire responses and clinical periodontal status) and selected supporting documents under a data use agreement, shared via secure transfer. No direct identifiers will be shared.