Reliability and Diagnostic Performance of Digital Versus Clinical Assessment of Oral Hygiene and Gingival Health in Older Community‐dwelling Adults

Aims This study evaluated the diagnostic performance and interexaminer reliability of digital versus clinical oral hygiene assessments in community‐dwelling older adults, focusing on the Plaque Index for Long‐Term Care (PI‐LTC), Quigley–Hein Index (QHI), and Marginal Gingival Index (MGI). Methods and Results Fifty‐two participants aged ≥ 65 years (mean 77.2 ± 6.8 years) underwent standardized clinical and digital examinations before (PI‐LTC, QHI, MGI) and after professional toothbrushing (QHI). Two independent digital examiners—one calibrated for gerodontology (D 1 ) and one uncalibrated (D 2 )—assessed intraoral scans obtained with a 3Shape TRIOS 4 system (Straumann). Inter‐ and intraexaminer reliability were determined using intraclass correlation coefficients (ICC), and discriminative performance was analyzed via area under the receiver‐operating characteristic curve (AUROC). Both PI‐LTC and QHI demonstrated strong discrimination (AUROC 0.85–1.00). The QHI showed the highest and most consistent reliability (ICC ≈ 0.65–0.75), whereas the PI‐LTC achieved higher sensitivity but moderate reproducibility (ICC ≈ 0.50), particularly in posterior regions. The MGI yielded fair to good reliability (ICC ≈ 0.45–0.55) and was more examiner dependent. The calibrated examiner (D 1 ) achieved near‐perfect agreement with the clinical reference (D 0 ), while the uncalibrated examiner (D 2 ) also performed acceptably but with lower accuracy (ΔAUROC ≈ 0.10–0.20). Conclusion Digital intraoral scanning enables reliable and valid assessment of oral hygiene in older adults. Examiner calibration substantially enhances diagnostic precision, though uncalibrated digital evaluations also remain clinically useful. The QHI offers superior reproducibility, whereas the PI‐LTC provides greater sensitivity for plaque risk detection. Clinical Trial Registration German Clinical Trials Register (DRKS), DRKS00032639, 19.07.2024