Classifying periodontal diseases--a long-standing dilemma.

Any attempt to group the entire constellation of periodontal diseases into an orderly and widely accepted classification system is fraught with difficulty, and inevitably considerable controversy. No matter how carefully the classification is developed, and how much thought and time are invested in the process, choices need to be made between equally unsatisfactory alternatives. Despite this dilemma, in the past hundred years, experts have periodically assembled to develop a new classification system for periodontal diseases, or to refine an existing one (1, 2, 4, 5, 11, 19, 58, 80, 81, 86, 91, 106, 122, 139).