6-YEAR PROGRESSION OF DESTRUCTIVE PERIODONTAL-DISEASE IN 2 SUBGROUPS OF ELDERLY CHINESE

Two GROUPS OF ELDERLY CHINESE WERE SELECTED from a large epidemiological sample on the basis of a low (''best'' group) or a high (''worst'' group) number of sites with attachment loss levels greater-than-or-equal-to 6 mm and/or pocket depth greater-than-or-equal-to 4 mm and at least 16 teeth present. Six years later the patients were clinically reexamined and the subgingival microflora was assessed. This paper presents the clinical characteristics of destructive periodontal disease progression among the two subgroups. The ''best'' group lost an average of 1.8 teeth, contrasting the average loss of 5.3 teeth among the ''worst'' group. Virtually all teeth lost among the ''worst'' group had a baseline attachment loss level greater-than-or-equal-to 4 mm, in contrast to 48% among the ''best'' group. While dental caries could be identified as a cause of tooth loss in both groups, the excess tooth loss among the ''worst'' group seems attributable to periodontal destruction. The average of 1.21 mm attachment/site lost among the ''best'' group was not statistically significantly different from the 1.36 mm/site lost among the ''worst'' group during the 6 years. Individual mean losses of attachment ranged from a gain of 0.03 mm to a loss of 3.19 mm. An attachment loss greater-than-or-equal-to 2 mm at a site was highly positively associated with a high initial attachment loss level (greater-than-or-equal-to 4 mm) at that site among the ''best'' group, whereas a highly negative association was seen among the ''worst'' group. This may indicate that progression in the ''best'' group mainly occurs in sites already ''marked'' for progression, whereas progression in the ''worst'' group continues to implicate new sites.