A New Classification of Palatal vaults: A Clinical Approach

I am presenting here a new classification for the Palatal vault in a completely edentulous patient.

Need for a classification: The general classification of palatal vaults as given by House is High, Medium and Low.
What does this indicate? It gives some idea about the depth of the palate, but so long as this information cannot be applied to a particular step in the fabrication of the denture, it has limited value! Should we do something different if a patient is categorised as House's High palate? or low?... In which area of the maxilla do we actually measure and assess that the vault is high or medium or low?

Therefore I have come up with a new classification that co relates the palatal vault to phonetic requirements.

In this classification the depth of the palate is measured at the 1st canine - premolar level, assuming that the tongue makes maximum contact in that zone of the palate during speech, especially linguo-palatal sounds.

Methodology employed :
After denture try-in, the region of the canine-1st premolar is marked on
 the ridge of the cast. An imaginary line joining these bilateral points is
 used as a reference and a perpendicular drawn from this line to the
 surface of the palate on the cast gives us the depth of the palate.



Based on this depth as measured in a large section of edentulous patients in our society, 3 categories of palatal vaults have been derived:

  SK1 - Shallow palatal vault. Depth : 0-5mm

SK2 - Medium palatal vault. Depth : 6-10mm 

                

SK3 - Deep palatal vault. Depth : greater than 11mm

This classification was derived from a study of measuring palatal depths by the above method for 50 patients.


Significance of the new classification:
Since it is based on the palatal depth in the region of the canine-1st premolar,(which is the most common region of the articulation of the tongue with the palate)it can be directly linked to phonetic requirements of complete dentures.
The canine-1st premolar region is the region where the palate can give an L beam effect to a denture. One would expect that SK3 category patients will have greater denture stability. The classification can thus give a prognosis of the denture stability.I am presently studying whether in patients with varying palatal depths, (Whether a patient is SK1 or SK2 or SK3 category); does the incorporation of palatal rugae make any difference to the speech of the patient or not?