Grade C molar-incisor pattern periodontitis classification and its challenges

Background: The classification of periodontitis has changed, establishing not just the severity and extent of disease but also more comprehensive risk assessment for patients and hopefully guiding more tailored treatment approaches. Although the new classification presented several benefits to the severity and risk of progression of disease, some limitations remain. This review highlights key gaps in the grade C and molar-incisor pattern (C-MIP) classification, particularly the exclusion of primary dentition involvement, which limits early awareness, diagnosis, treatment, and research. Additionally, the current “grade C” category includes a broad spectrum of patients, ranging from systemically healthy young individuals with early onset and rapid disease progression to older adults whose disease is associated with modifying factors. This overlap masks key clinical and biological differences, complicating efforts to identify susceptibility profiles and tailor treatment. Moreover, cases extending beyond the molar-incisor pattern, including premolars or atypical presentations, pose challenges to the current classification system. These patients often exhibit early onset, familial aggregation, rapid progression, and absence of systemic risk factors, suggesting a unique susceptibility profile that may not be adequately captured by the current classification and deserve proper categorization to be better studied and treated. Conclusion: In the conclusion of this paper, we suggest expansion and clarification of the current classification system to: (1) recognize periodontitis in the primary dentition; (2) distinguish patients with grade C periodontitis by the presence or absence of modifying factors; and (3) introduce a subclassification for grade C cases predominantly affecting young patients. These refinements may improve diagnostic accuracy and support more targeted research, prevention, and treatment for at-risk youth.