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.
Because of this, and because of the difference in their period of revolution, the distance between Earth and Mars can vary greatly. At its closest approach, Mars is about 50 million km from Earth; at its farthest almost 402 million km (when Earth and Mars are on opposite sides of the Sun). The average distance between Earth and Mars is over 200 times as far as it is from the Earth to the Moon.