Dental carries is caused by-

Ans. is 'b' i.e., Streptococcus mutans Viridans streptococcio Viridans streptococci consists of multiple species of alpha hemolytic streptococci,o Various species of viridans streptococci are -# S. salivarius# S. mitis# S. sanguis# S. mutanso They are ordinarily nonpathogenic but can on occasion cause disease. In persons with preexisting cardiac lesions, they may cause bacterial endocarditis, Str. sanguis being most often responsible.o Str. mutans is important in causation of dental caries.o The transient viridans streptococcal bacteremia induced by eating, tooth-brushing, flossing and other source of minor trauma, together with adherence to biological surfaces, is thought to account for the predilection of these organisms to cause endocarditis.o Viridans streptococci are also isolated, often as a part of a mixed flora, from sites of sinusitis, brain abscess and liver abscess.o Viridans streptococcal bacteremia occurs relatively frequently in neutropenic patients, particularly after bone marrow transplantation or high dose chemotherapy for cancer,o Treatment of varidans streptococcal infections includeBacteremia in neutropenic patients - Vancomycin.Other infection - Penicillin.