Inter-examiner reliability in periodontal diagnosis and treatment planning using the 2018 classification and the EFP S3 clinical guideline

Abstract

Abstract Background The 2018 Classification of Periodontal and Peri-Implant Diseases and Conditions introduced a multidimensional diagnostic framework incorporating staging, grading, and extent, the European Federation of Periodontology (EFP) S3-level clinical practice guidelines provided structured treatment recommendations. Although these frameworks aim to improve diagnostic precision and therapeutic standardization, their inter-examiner reliability in routine clinical settings remains insufficiently validated. This study evaluated diagnostic and treatment planning agreement between clinicians with different levels of experience. Methods In this single-center cross-sectional inter-examiner reliability study, 148 recruited patients diagnosed with periodontitis were included. Comprehensive clinical and radiographic records were obtained for each patient. Two blinded examiners, a first-year periodontology resident and an experienced periodontist, independently classified stage, grade and extent according to the 2018 Classification, and developed treatment plans based on the EFP S3 Clinical Practice Guidelines. Inter-examiner agreement was assessed using Cohen’s kappa (κ) with statistical significance set at p < 0.05. Results Inter-examiner agreement for staging was moderate (κ = 0.463), whereas grading (κ = 0.899) and extent (κ = 0.816) demonstrated almost perfect agreement. Complexity-related variables showed variable reliability, with substantial agreement for flaring (κ = 0.715) but lower kappa values for bite collapse (κ = 0.231) and drifting (κ = 0.116), influenced by low prevalence. Treatment planning agreement was perfect for supragingival biofilm control and diabetes management (κ = 1.000) and almost perfect for smoking cessation counseling (κ = 0.973). Moderate agreement was observed for subgingival instrumentation (κ = 0.487), adjunctive chemotherapeutic agents (κ = 0.543), systemic antibiotics (κ = 0.519), resective surgery (κ = 0.549), and regenerative surgery (κ = 0.603). Conclusions Risk-based components of the 2018 Classification demonstrate high reproducibility, whereas staging, particularly differentiation between Stage III and Stage IV, remains challenging. Treatment decisions for non-surgical therapy are more consistent than those involving surgical or adjunctive interventions. Enhanced calibration and structured decision-support tools may improve uniformity in advanced case management.