[Occurence of dental plaque among Norwegian children with systematic school dental care. A method for identification of patients with special need for dental plaque control].
The prevalence of dental plaque was assessed in 1534 school children 7-12 years old in Porsgrunn, Norway. Only the first molars and the incisors were examined. In each child 48 scorings were carried out by the Plaque Index (Pl I) (Silness & Löe 1964). The frequencies of Pl I score 0, 1 and 2 were calculated per individual, school class and school. Score 0 expresses an optimal situation whereas score 2 is assumed to indicate the need for treatment. These features have been visualized, and the distribution pattern seems to be suitable for dental public health workers. Mean Pl I was 1.50. Score 3 was not observed. 55% of the tooth surfaces was covered with dental plaque corresponding to score 2, whereas score 1 was observed in 40%. Children with score 0 on all tooth surfaces were not registered. Great variation in plaque prevalence was found between the school classes. The 6. grade (aged 12 years) children showed the best condition.