Dental caries is caused by

Streptococcus mutans is an alpha Hemolytic streptococcus which is a pa of the normal flora of the oral cavity. This gram-positive coccus is commonly found in the mouth from where it can spread to cause dental caries or endocarditis in individuals with risk factors(dental extraction in individuals with damaged hea valves). The bacteria has a polysaccharide coat that allows it to stick to teeth and also to the damaged hea valves. It produces acid from sugar in saliva and this promotes erosion of tooth enamel. Reference: Textbook of Microbiology; Anathanarayan and panicker's; 10th edition; Page no: 221