I had a root canal to last upper molar and also molar next to it (this canal was done through a crown and endo went into tooth twice). Since then, I have had toothaches on and off. When I get the ache, the doc puts me on antibiotics. I have had 3 rounds of PenVK and am now on amoxicillin. I get better on the antibiotics, but then about a week after I finish them, the pain returns, so I'm put back on. How many rounds of antibiotics is okay? Also, all my teeth are shifting on this right upper side so I have made apt with an orthodontist. Can braces be put on even though I'm having root/infection problems and the crowns aren't sealed off? What would be causing the teeth to shift so? HELP