Recordings of supragingival plaque, bleeding, suppuration and probing depth were obtained for 42 months following initial periodontal therapy. Scores accumulated after various time intervals during monitoring were studied for their predictive value in revealing probing attachment loss as determined by regression analysis during the 0-42 month period. Accumulated plaque scores demonstrated low predictability. Accumulated bleeding scores showed modest predictive values. Suppuration on probing was not a frequent finding during the observation interval and also had modest predictive power. Increase in probing depth compared to baseline and deep residual probing depth had modest predictability after 3 and 12 months, but showed increasing accuracy in revealing probing attachment loss over later time intervals. After a few years of maintenance, increase in probing depth, particularly if combined with high frequency of bleeding on probing, showed the highest predictive value for probing attachment loss of the scores examined.

The healing response of non-molar sites, molar flat surface sites, and molar furcation sites was investigated in 19 adult periodontitis patients following a periodontal therapy of plaque control and root debridement. A total of 2472 sites were monitored by recordings of dental plaque, bleeding on probing, probing depth, and probing attachment levels every 3rd month for 24 months. The results demonstrated that in sites with initial probing depth of 4.0 mm or greater, molar furcation sites responded less favorably to the therapy as compared to molar flat surface sites or non-molar sites. This was demonstrated by higher mean scores for bleeding on probing, less reduction in probing depth, and a mean loss of probing attachment of 0.5 mm over 24 months. Site analyses using linear regression showed a higher % of deeper sites with probing attachment loss for the molar furcations than either molar flat surface or non-molar sites. Among sites initially 7.0 mm or deeper, 21% of molar furcations were identified as showing probing attachment loss as compared to 7% of the molar flat surface sites and 11% of the non-molar sites.