The correlated binomial model in the analysis of clinical diagnostic test parameters for recurrence of periodontitis

Validity of the "Community Periodontal Index of Treatment Needs" (CPITN) for population periodontitis screening

The aim of the present study was to validate two versions of CPITN for periodontitis diagnosis. A sample of 400 individuals underwent full mouth periodontal examination including Clinical Attachment Loss, Periodontal Pocket Depth, and Sub-gingival Calculus. Full and partial CPITN versions were derived from this exam (gold standard). Contingency tables were constructed and operational characteristics obtained, as well as ROC curves. The results show 58% sensitivity for full CPITN and 80.6% specificity. Positive and negative predictive values were 87% and 46.3%, respectively. According to the test, estimated periodontitis prevalence was 46%, while the figure obtained with the gold standard was 69%. The partial version of the CPITN showed 50% sensitivity and 87.1% specificity. Positive and negative predictive values were 89.6% and 43.9%, respectively. Estimated periodontitis prevalence, through partial CPITN, was 30.5%. Adjusted global agreement (kappa) for partial and full CPITN was 0.32 and 0.29, respectively. Both CPITN versions disagreed significantly with gold standard results (chi-square p < 0.001). As a conclusion, both total and partial CPITN failed to reflect the real periodontal status of the sample.

Clinical effects of scaling and root planing in adults infected with Actinobacillus actinomycetemcomitans

The periodontal pathogen Actinobacillus actinomycetemcomitans can frequently be isolated from subgingival plaque of adults with chronic inflammatory periodontal disease and individuals with plaque-induced gingivitis. Problems with the persistence of the organism after thorough debridement of root surfaces have been reported. In the present study clinical effects of the hygienic phase of periodontal therapy in ten adult patients with moderate or advanced periodontitis harbouring A. actinomycetemcomitans were analysed. Since proper analysis of highly correlated data within a given patient is crucial for appropriate interpretation, a major objective of this study was to compare the results of different models derived from logistic regression of clinical and microbiological factors on gain or loss of clinical attachment under different assumptions. Subgingival samples from every tooth present were obtained before and 6 weeks after thorough subgingival scaling, and selectively cultivated for the organism. A relevant gain of clinical attachment of 2 mm or more was observed at a total of 36% of periodontitis sites after scaling. Overall, loss of attachment of 2 mm or more was observed at 8% sites. Most loss occurred at sites with gingival enlargement (15%), whereas 3% periodontitis sites lost 2 mm or more. In multivariate analyses erroneously assuming either independence of data or correctly considering the correlated structure of observations attachment gain was mainly associated with deep probing depths at the outset. Presence or absence of A. actinomycetemcomitans before or after therapy was not included into the periodontitis models. Also, loss of attachment of 2 mm or more after subgingival scaling was not influenced by the organism. A direct comparison of the results obtained with both approaches of logistic regression may be helpful in the assessment of the influence of the magnitude of correlation of the data on the regression coefficients.

Clinical indicators of probing attachment loss following initial periodontal treatment in advanced periodontitis patients

16 advanced periodontitis patients were subjected to initial periodontal treatment and monitored every 3rd month during 42 months. Clinical characteristics at baseline and during the 42-month maintenance period were investigated for their association with probing attachment loss over the 42-month period, both on a patient level and on a site level. On a patient level, averaged full-mouth plaque and bleeding on probing scores over the maintenance interval showed little association with probing attachment loss. Little association was also observed for % sites with depth > or = 6 mm at baseline. However, a notable relationship was seen for % sites > or = 6 mm at 3 months. This finding initiated a separation of the 16 subjects into 2 groups based upon % sites > or = 6 mm at 3 months (groups 'high' and 'low'). Site level analyses for these groups showed little association between frequent presence of plaque at the sites over the maintenance interval and probing attachment loss. Frequent bleeding on probing showed limited relationship with attachment loss for group 'low', but an appreciable association for group 'high'. The findings suggest that advanced periodontitis patients with multiple residual probing depths > or = 6 mm at re-evaluation run a greater risk of developing sites with additional attachment loss than patients with few such residual depths. For such higher risk patients, bleeding on probing at maintenance examinations may be a useful indicator of subsequent deterioration at a site level.

Effect of root canal filling materials containing calcium hydroxide on the alkalinity of root dentin

The effect of root canal filling pastes containing calcium oxide resp. calcium hydroxide on the alkalinity of extracted human teeth was investigated using a colour indicator (cresol red). An aqueous suspension of calcium hydroxide (Pulpdent), which is normally used for temporary root canal filling, most consistently produced alkalinity. Removal of the smear layer following instrumentation of the root canal led to increased proportion of alkaline-positive spots in dentinal locations distant from the canal. A clearly smaller effect was found with a calcium salicylate cement (Sealapex) and an oil-paste (Gangraena Merz), both of which are available for definite root canal fillings. Following removal of the smear layer, these hard-setting preparations caused moderate alkalinity in dentin adjacent to the canal but no effect was observed in locations more distant from the canal. Neither at locations adjacent to nor distant from the root canal was alkalinity found when another calcium salicylate cement (Apexit) was used. Apparently the release of hydroxyl ions into root dentin from calcium hydroxide containing root canal filling materials is not solely influenced by the absolute amount of calcium hydroxide, but also depends on other ingredients which variably inhibit the release of these ions.