SPG11 and chronic periodontitis: The expression frequencies of the ALS3, ALS4, ALS5, ALS9, SAP4, SAP5, and SAP6 genes were lower in the strains isolated from chronic periodontitis compared to those from moderate periodontitis and gingivitis, which suggests that, in a more severe stage of the disease where there is a high destruction of tissues, these adhesion and protease genes are not essential.