Lateral throat form re-classified using a customized gauge: A clinical study

A common problem faced by prosthodontists is achieving adequate retention and stability in the mandibular dentures. Recording the lateral throat form (LTF) correctly can aid in the retention and stability. Till date, Neil's classification has been considered as the gold standard in measuring the depth of the LTF. This is a subjective classification and varies among different operators. In this study, a customized tool was used to measure the depth of the LTF, and a classification was proposed according to the measured depths.

The objective of this study is to measure the exact depth of LTF using customized gauge and to propose a classification based on the measured depth.

A customized gauge was made to measure the depth of the LTF. Two different observers classified the LTFs according to Neil's classification and according to the proposed classification in a total group of 50 patients. The customized gauge was inserted into the alveolo-lingual sulcus to measure the depth. The Pearson's correlation statistics was carried out to observe the inter-observer relationships of sulcus depth using this customized gauge. ANOVA test was used to compare the mean depth of the sulcus as measured by observers 1 and 2.

There was more inter-observer variability when Neil's classification was used as compared to the one with the proposed classification using the gauge. The inter-observer agreement for the proposed new classification was assessed by Cohen's kappa value, with P < 0.001. The mean depth of the sulcus as calculated by observers 1 and 2 was compared with ANOVA test and found to be significant with P < 0.001.

The proposed new classification for LTF gave consistent results and was easier to use with less variability when compared to the Neil's classification.