Longitudinal changes in periodontal disease in untreated subjects.

About 300 subjects, 20-79 years of age were recruited for a longitudinal study on the effect of periodontal therapy. The result of a baseline examination have been reported earlier. Following this baseline examination, the subjects were monitored for 24 months without therapy. Re-examinations were performed after 12 and 24 months. All teeth including the 3rd molars were included in the examinations. Presence of plaque was assessed at 4 surfaces per tooth and gingivitis, probing pocket depth, probing attachment levels were assessed at 6 locations per tooth. Out of the subject sample examined at baseline, 57 individuals failed to return for either the 1st, the 2nd or both re-examinations. An analysis was performed regarding the periodontal status at baseline, of the respondents and non-respondents. The results from the follow-up examinations of the participating 20 to 79 year-old subjects revealed that the sample underwent, during a 2-year period, only minor changes with respect to a series of different parameters characteristic of periodontal disease. Thus, the mean values of probing pocket depth and probing attachment level failed to change between baseline and the re-examinations after 1 and 2 years. Even if the mean values underwent only minor changes, however, certain subjects within each age category improved their periodontal conditions, whereas other subjects worsened. Furthermore, the findings of the re-examinations revealed that there was a strong correlation between improving plaque levels and gingivitis. The relationship between supragingival plaque levels and changes with respect to probing depth and attachment levels were weak.