Differing profiles of periodontal disease in two similar South Pacific island populations.

The periodontal condition of a cross-section of individuals aged between 15-59 years was characterised from clinical and radiographic observations of dental calculus, gingival inflammation, the level of the gingival attachment , alveolar bone loss, teeth missing or requiring extraction for periodontal reasons. The common characteristics of the profile in Tonga and W. Samoa were a high prevalence of the factors common to periodontal disease: calculus and gingival inflammation; a progressive apical movement of the gingival attachment; and alveolar bone loss. All these criteria showed a positive age dependency with calculus (particularly subgingival calculus) and gingival inflammation being very commonly associated with all tooth types at an early age, less than 30 years. Tooth loss observed was presumed to be previously associated with periodontal disease because the prevalence of dental caries was very low in both populations. Substantial differences were observed in the number of missing teeth between Tongan and Samoan populations, the Tongan subjects having a high rate of tooth loss. From radiographic interpretations of the periodontal conditions fewer subjects in Tonga were assessed as having no disease, and there was a higher prevalence of progressive destructive disease in Tonga than in W. Samoa. The proportion of subjects in both countries with no disease decreased rapidly with age. There was no evident explanation of the greater severity of disease in Tonga than in W. Samoa. The prevalence of microbial plaque, calculus and gingival inflammation was very high in all subjects at all ages particularly over 30 years in both populations.