Reliability study of Mahajan's classification.

Sir,

It was interesting and thought-provoking to read the article by Mahajan et al.[1] regarding the reliability study of his classification. The authors have endeavored to validate the “use of Mahajan's modification of Miller's classification for gingival recessions as it has all the qualities of a reliable classification system, and it eliminates the limits and drawbacks of Millers classifcation.”[1]

One of the major drawbacks of Miller's classification[2] is the absence of information about keratinized gingiva.[3] According to Pini-Prato “A tooth with gingival recession always presents a certain amount of keratinized tissue (free gingiva), the marginal tissue recession cannot extend to or beyond the mucogingival junction (MGJ). Therefore, Class II could never exist and Classes I and II would represent a single category.”[3] This fact was stated in the context of Miller's classification but also applies to the Mahajan's classification.

Second major drawback of Miller's classification is absence of criteria to classify marginal tissue recession with inter-proximal bone loss, which does not extend to the MGJ.[34] Although in the present article, authors have tried to answer this question by stating that there is a clear delineation between the recession groups (Mahajan's Classes I and II are recessions with only soft tissue loss, while Classes III and IV are with inter-proximal bone loss).[1] However, similar distinction exists in original Miller's classification as well (Miller's Classes I and II deal with soft tissue loss on the facial aspect with no interdental bone/soft tissue loss and Classes III and IV deal with facial loss with inter-proximal loss). In this aspect, Miller's classification at least specifies the level of facial loss (marginal tissue loss to or beyond MGJ), whereas Mahajan's classification has no provision to specify the loss of facial tissue. Without any component to elucidate the extent of facial loss in Mahajan's Classes III and IV, the marginal tissue recession with inter-proximal bone loss, which does or does not extend to the MGJ cannot be clearly classified.

Mahajan et al.[1] have also pointed out the inability to classify palatal/lingual recessions as the limitation of their classification system. This limitation has been called “theoretical” by the authors. Do authors mean to say that palatal/lingual recessions are imaginary/speculative? This limitation is present in Miller's classification as well.[3] One of the characteristics of any classification system is exhaustiveness.[15] Exhaustiveness means that classification should be comprehensive, and accommodate every member of the group.”[1] Inability to classify palatal/lingual recession defects in both Miller's and Mahajan's classification means that the criteria of exhaustiveness remain unfulfilled.

Authors justifying the “inability to classify palatal/lingual recessions” by emphasizing that patients ask for the treatment of only facial/buccal gingival recessions may not be an acceptable explanation. A patient not asking for a treatment of a palatal/lingual recession cannot be the basis to eliminate or not classifying palatal/lingual recession defects. There are countless number of patients who do not ask for treatment of facial/buccal gingival recessions defects, so does that mean that even facial/buccal recession cases should not be classified in such patients?

Recessions are recorded during case history recordings. Absence of criteria to record palatal/lingual recession defects will result in partial and under-recording of recession defects. Partial/incomplete recording leads to an erroneous diagnosis, prognosis, and hence treatment planning.[4] What would any investigator do in a case where only palatal or lingual recessions are present? How would any investigator record them? Overlooking of palatal/lingual recessions for the fact that the patients don’t ask for the treatment will lead to grossly erroneous diagnosis of a case. Interestingly, Kumar and Masamatti's classification[4] overcomes all the three major limitations mentioned above.