Antibiotics cannot cure a root canal infection because the source of the infection is inside the tooth where there is no blood supply; without blood supply there is no mechanism to deliver antibiotics. The cure is the complete shaping, cleaning and obturation (sealing) of the contaminated root canal space.
Thanks for the A2A, Joseph Boyle. You've already gotten plenty of answers, but since they differ a bit, I may as well cast my vote. According to http://Space.com The minimum distance from the Earth to Mars is about 54.6 million kilometers. The farthest apart they can be is about 401 million km.
UCSB Science Line. Mars is about 35 million miles from the earth -- and was closer on Aug 27. 2003 than at any time in the last several thousand years. Over two years, the distance varies from about 39 million to about 240 million miles.