It causes bad breath, discolors teeth and promotes tooth decay that leads to tooth loss. Spit tobacco users have a decreased sense of smell and taste, and they are at greater risk of developing cavities. The grit in snuff eats away at gums, exposing tooth roots, which are sensitive to hot and cold temperatures and can be painful. The sugar in spit tobacco further contributes to decay. Spit tobacco users also have a hard time getting their teeth clean.