SOST and abscess: Correlation matrix analysis showed good to moderate correlation between PAI-AP severity and PAI-abscess score (r = 0.811), OHI score (r = 0.762), and GCF sclerostin (r = 0.496); moderate to low correlation between PAI-abscess score and OHI-S (r = 0.495), GCF sclerostin (r = 0.476), and GCF RANKL (r = 0.300); and low, but statistically significant, correlation between GCF sclerostin and GCF RANKL levels (r = 0.476).