Final answer:
Streptococcus mutans is the microorganism most commonly associated with root surface caries. It produces organic acids that dissolve tooth minerals, leading to decay. Streptococcus mutans can also spread throughout the body, causing inflammation and potential health issues.
Step-by-step explanation:
The microorganism most commonly associated with root surface caries is Streptococcus mutans. This bacterium is a major cause of cavities and is found in the mouth, particularly in plaque biofilms on teeth. Streptococcus mutans produces organic acids that dissolve the minerals of the tooth, leading to decay. It can also spread throughout the body, causing inflammation and potential health issues.