infection in root canal

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

[Jerome Bogin, D.D.S.]

I can not tell you what is causing the teeth to shift without seeing you. I am not inclined to believe that you should not       be on an antibiotic regiment every time you are in pain.Either the root canal is retreated or a surgical procedure (apicoectomy) is done I think there has to be a concerted effort to remove the infection without using the antibiotics.The orthodontics should be considered after the teeth are asymptomatic.

[mike1105]

i would not pursue orthodontics until the problem with tis molar is solved. you may have a fracture, a periodontal problem, or a root that has not been cleaned out of nerve tissue. not all root canals work. I'd get another opinion on the root canal from a different endodontist. continually placing you on antibiotics everytime the tooth flares up is not a permanet fix. the source of the problem needs to be addressed. then, see a good general dentist for a full exam and complete written treatment plan detailing the other prolems in your mouth, including the shifting---