Site-level progression of periodontal disease during a follow-up period

<div><p>Periodontal disease is assessed and its progression is determined via observations on a site-by-site basis. Periodontal data are complex and structured in multiple levels; thus, applying a summary statistical approach (i.e., the mean) for site-level evaluations results in loss of information. Previous studies have shown the availability of mixed effects modeling. However, clinically beneficial information on the progression of periodontal disease during the follow-up period is not available.</p><p>We conducted a multicenter prospective cohort study. Using mixed effects modeling, we analyzed 18,834 sites distributed on 3,139 teeth in 124 patients, and data were collected 5 times over a 24-month follow-up period. The change in the clinical attachment level (CAL) was used as the outcome variable. The CAL at baseline was an important determinant of the CAL changes, which varied widely according to the tooth surface. The salivary levels of periodontal pathogens, such as <i>Porphyromonas gingivalis</i> and <i>Aggregatibacter actinomycetemcomitans</i>, were affected by CAL progression. “Linear”- and “burst”-type patterns of CAL progression occurred simultaneously within the same patient. More than half of the teeth that presented burst-type progression sites also presented linear-type progression sites, and most of the progressions were of the linear type. Maxillary premolars and anterior teeth tended to show burst-type progression. The parameters identified in this study may guide practitioners in determining the type and extent of treatment needed at the site and patient levels. In addition, these results show that prior hypotheses concerning "burst" and "linear" theories are not valid.</p></div

Multilevel logistic regression model with repeated measures to distinguish “linear” and “burst” progression during the 24-month follow-up period.

<p>Multilevel logistic regression model with repeated measures to distinguish “linear” and “burst” progression during the 24-month follow-up period.</p

Multilevel random intercept model for changes in CAL between the baseline and after 24 months (Model 1).

<p>Multilevel random intercept model for changes in CAL between the baseline and after 24 months (Model 1).</p

CAL change patterns during the 24-month follow-up period.

<p></p><p></p><p></p><p>(A) Changes of the improved, slightly improved, stable, slightly progressed, progressed and fluctuated categories.</p><p>···▲···: Improved, ··△···: Slightly improved, ─●─: Stable.</p><p>---□---: Slightly progressed, ---■---: progressed, ─■─: Fluctuated</p><p>Differences in the CAL changes over 24 months were classified into six categories: ≤ -3 mm, improved; between -3 mm and -2 mm, slightly improved; between -1 mm to 1 mm, stable; between 1 mm and 2 mm, slightly progressed; 3mm, progressed. In addition, cases with both ≤ -3 mm and ≥ 3mm were classified as fluctuated.</p><p></p><p></p><p>(B) CAL progression patterns of the progressed category</p><p>···▲···: Cluster 1, ···△···: Cluster 2, ─●─: Cluster 3.</p><p>─□─: Cluster 4, —■—: Cluster 5</p><p>A hierarchical cluster analysis was performed for the progressed type portrayed in Fig. 2(A), and 5 clusters were generated. The slope of cluster 1 was moderate, and the slopes of the other clusters were steep. Cluster 1 may correspond to the linear-type progressed sites, and the other clusters may correspond to the burst-type progressed sites.</p><p></p><p></p><p></p> <p>(A) Changes of the improved, slightly improved, stable, slightly progressed, progressed and fluctuated categories.</p> <p>···▲···: Improved, ··△···: Slightly improved, ─●─: Stable.</p> <p>---□---: Slightly progressed, ---■---: progressed, ─■─: Fluctuated</p> <p>Differences in the CAL changes over 24 months were classified into six categories: ≤ -3 mm, improved; between -3 mm and -2 mm, slightly improved; between -1 mm to 1 mm, stable; between 1 mm and 2 mm, slightly progressed; 3mm, progressed. In addition, cases with both ≤ -3 mm and ≥ 3mm were classified as fluctuated.</p> <p>(B) CAL progression patterns of the progressed category</p> <p>···▲···: Cluster 1, ···△···: Cluster 2, ─●─: Cluster 3.</p> <p>─□─: Cluster 4, —■—: Cluster 5</p> <p>A hierarchical cluster analysis was performed for the progressed type portrayed in Fig. 2(A), and 5 clusters were generated. The slope of cluster 1 was moderate, and the slopes of the other clusters were steep. Cluster 1 may correspond to the linear-type progressed sites, and the other clusters may correspond to the burst-type progressed sites.</p

Mean values of the CAL changes during the 24-month follow-up period.

<p>CAL changes during the 24-month follow-up period are separately illustrated by the CAL at baseline and by the type of tooth surface. Baseline CAL values are divided into three groups: (A) <3mm; (B) 3 mm; and (C) > 3 mm.</p> <p>─●─: Maxillary molar, ---■---: Maxillary premolar, ···▲···: Maxillary anterior,</p> <p>─○─: Maxillary molar, ---□---: Maxillary premolar, ···△···: Maxillary anterior</p> <p>Baseline CAL values of < 3mm gradually deteriorated, while baseline CAL values of > 3 mm improved. Molars with a baseline CAL of 3 mm progressed, whereas premolars and anterior teeth were stable or improved.</p> <p>CAL: clinical attachment level.</p