The use of planimetry to record and score the modified Navy index and other area-based plaque indices. A comparative toothbrush study

Abstract

Many plaque-scoring methods are based on a subjective assessment of the amount of tooth surface covered by plaque or the presence or absence of plaque at specific sites. The 2x modified Navy plaque index is an example of the latter and requires chairside decisions from 9 zones of all buccal and lingual tooth surfaces, i.e., up to 576 for a complete dentition. The present study describes a procedural modification to the index, whereby plaque is recorded using an established planimetric plaque area method. Scoring is then performed using an overlay away from the clinic. To test the method, plaque-area measurements were made during a 30-subject, crossover study to compare plaque removal following single toothbrushings with 3 different types of manual toothbrush. Consistent with many such studies, no significant differences in plaque removal were noted between the brushes. The method was found quick and simple at the chairside, provided a permanent record of plaque distribution and could be analysed by clinical or nonclinical personnel under ideal conditions. The same method could be employed for other plaque indices based on area or site subjective decisions.