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.
Its distance from the Earth varies between 356,000 and 407,000 km (221,000 and 253,000 miles) in the course of each month; the average distance is 384,400 km (238,900 miles), less than 1% of the distance to Venus and Mars, even at the time of their closest approach.