Partial indices as indicators of the severity and prevalence of periodontal disease.

The purpose of this study was to analyse the reliability of partial examination in the assessment of the average severity and the prevalence of periodontal disease. A total of 126 subjects aged 15-30 years and 160 subjects aged 31-68 years were examined for the presence or absence of gingival bleeding, supra- and subgingival calculus and pocket depths of 4-5 mm or 6 mm and over on six surfaces of each remaining tooth. From this pool of data three sets of average severity and prevalence scores were extracted. One was based on the full mouth examination; one on observations made from the ten index teeth of the Community Periodontal Index of Treatment Needs (CPITN); and one on the six index teeth of the Periodontal Disease Index. Average severity scores were obtained as accurately from the six Ramfjord teeth as from full mouth examinations for all periodontal disease indicators except for 6 mm or deeper pockets. When the assessments were based on the ten CPITN index teeth, the average severity scores exceeded those based on full mouth examinations for all indicators recorded and the prevalence figures were higher than those based on the six Ramfjord teeth. Even with the CPITN there was an under-estimate of the proportion of individuals affected, ranging from 16 per cent for 4-5 mm pockets to 21 per cent for 6 mm and deeper pockets in the older age group.(ABSTRACT TRUNCATED AT 250 WORDS)