Assessment of Reliability of Three Indices Measuring Gingival Overgrowth

Numerous indices have been used to grade the severity of gingival overgrowth which led to suspicion regarding the results concerning its prevalence and pathogenicity. The aim of this study was to assess the concordance of three different gingival overgrowth indices, which were used widely in previous studies, and check their reliability and reproducibility.

A total of 30 full-mouth plaster casts and 90 intra-oral photographs collected from 30 patients diagnosed with gingival overgrowth were included in our study. Three trained examiners performed measurements twice on plaster casts using gingival hyperplasia index (A index) and hyperplastic index (B index). Intraoral photographs were assessed also twice using (C index).

Concordance of intra-examiner and inter-examiner reliability of the recorded measurements was carried out for each index using weighted kappa (K), with a confidence interval of 95%. The A index revealed intra-examiner total kappa values between 0.724-0.876 for horizontal measurement and 0.512-0.823 for vertical measurement, and inter-examiner total kappa values between 0.255-0.626 horizontally and 0.235-0.279 vertically. The B index presented intra-examiner total kappa values between 0.587-0.868 horizontally and 0.653-0.855 vertically; and inter-examiner total kappa values between 0.393-0.595 and 0.372-0.635 for horizontal and vertical measurements, respectively. The C index achieved the highest intra-examiner concordance with total kappa values between 0.758-0.855 and inter-examiner total kappa values between 0.716-0.804.

The C index evaluated through intraoral photographs is considered the most reliable and applicable method to be utilized. The C index is suggested to be used in large scale populations with its definite detailed criteria.