Provided herein are aptamers that bind specifically to the surface proteins of periodontal pathogens. Also provided herein are methods for detecting and treating periodontal disease in a subject. The method comprises detecting bacteria associated with periodontal disease by use of the present aptamers to analyze a sample taken from a gum pocket of a tooth of the subject; and treating the periodontal disease of the subject by administering to the gum pocket of the tooth a bactericide or an anti-microbial phototherapy to eradicate the bacteria associated with periodontal disease.