Diagnosis of Stage III Periodontitis and Ambiguities of the "Gray Zones" in Between Stage III and Stage IV.

INTRODUCTION: How to best classify the Stage III and IV periodontitis cases that share common features of the most severe clinical attachment loss and the most severe radiographic bone loss? CASE PRESENTATION: Two patients presented features of generalized periodontitis, with severe probing depth and clinical attachment loss that would meet inclusion in both Stage III and IV. The cases retained all teeth but were further complicated by teeth drifting and secondary occlusal trauma. Appropriate disease classification required clinical judgement and led to the final classification of Stage III, Grade C for both cases. CONCLUSION: Patient-based clinical judgement, aiming for long-term preservation of natural dentition, drives the final assignment of staging when the case falls in the "gray zone" that focuses on major differences in Stage III and IV periodontitis.