Extent and Severity Index based on assessments of radiographic bone loss

The purpose of the present study was to develop a partial recording system based on the principles of the Extent and Severity Index, aiming at describing the degree of radiographic alveolar bone loss on a population level. The data analyzed were derived from a subject sample comprising 531 individuals aged 25-75 yr. In these subjects alveolar bone level (ABL) was radiographically assessed at all approximal tooth surfaces. An ABL value of greater than 2 mm was required for a tooth site to be included in the computation of a full mouth bivariate Extent and Severity Index (FESI). A partial recording index (PESI-2) based on 18 ad hoc selected tooth sites depicted in one periapical and one vertical bitewing radiograph was evaluated in comparison with the FESI as well as with partial recording indices based on the 9 and 18 tooth sites which displayed the highest correlation with full mouth scores (PESI-9 and PESI-18, respectively). It was shown that all three partial recording systems generated values reasonably close to the full-mouth scores. However, the fitness of all partial indices varied with age. The potential of the partial indices to predict full-mouth scores could be further enhanced via simple regression models. Such an evaluation should, ideally, be carried out in an independent subject sample.