A plaque index for occlusal surfaces and fissures. Measurement of repeatability and plaque removal.

Plaque indices have largely been developed for buccal and lingual tooth surfaces. There has been minimal interest in plaque accumulation on occlusal surfaces despite the predilection for caries at these sites. A numerical plaque index (0-5) is described based on the presence and distribution of plaque in the fissures and over the occlusal surfaces of permanent molar and premolar teeth. The repeatability of a single examiner in scoring the index was performed using 4 groups of 10 subjects. Each group of volunteers suspended tooth cleaning for 48 h and the index scored after disclosing plaque deposits. The index was rescored 60-90 min later. Plaque area was also determined by drawing the outline of plaque onto grids. Except for one condition of repeatability for one group, the 4 conditions of repeatability in scoring the index were met for all 4 groups of subjects. The sensitivity of the index and area recordings to detect plaque removed by brushing was then evaluated. A group of 10 subjects had plaque scored by index and area after suspending toothcleaning for 48 h. Subjects were then randomly allocated to brush or not brush their teeth and plaque rescored. The experiment was then repeated and brushing or not brushing crossed over. Highly significant differences between brushing and no brushing plaque indices and areas were determined. In conclusion, the occlusal fissure plaque index was easy to apply, repeatable and sufficiently sensitive to detect plaque removed by brushing. The index could find use as an additional measure of oral hygiene, in clinical trials on plaque control and possibly epidemiological studies relating to caries.