If what the dentist did does not meet the standards for acceptable dental care--which appears to be the case from what you write--then you may have a malpractice claim. If so, you could potentially recover for pain and suffering, if significant enough; for medical costs (like the cost to have someone fix the problem); and for lost wages (if you miss work). It would be worthwhile to speak to a medical malpractice attorney about your situation, especially one who provides a free consultation.