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.
Since Earth and Mars both orbit the Sun but at different distances and different speeds, the distance varies. So Earth and Mars can be as close as about 55 million kilometers, or as far as about 400 million kilometers - quite a difference. On average, they're about 225 kilometers apart.