SOD1 and chronic periodontitis: A wide distribution of ALS genes was detected globally in the strains across the three diagnoses, where ALS1 (79/80), ALS3 (70/80), ALS4 (79/80), ALS6 (77/80), ALS7 (78/80), and ALS9 (76/80) were found in most strains from gingivitis, moderate periodontitis, and chronic periodontitis.