what is the difference between an oral antibiotic and an oral antibacterial?

Answer 1

An antibiotic kills germ colonies that have already invaded and grown. An antibacterial kills a few germs that may be in your mouth so that they don't invade and grow large colonies which would result in an abcess (large pocket of infection).

Answer 2

Aside from the commonality of being taken orally, one is for broad spectrum bacteria (antibacterial) while the other one can kill more bacteria and viruses than the first one.