If the dentist or his/her staff committed malpractice in not making the dentures properly, you could sue him or her for damages--such as for the cost of new dentures. Malpractice, or literally bad practice, is not providing medical care that is at the generally accepted level, whether due to carelesness, inadequate training, not having the proper tools, etc. Forming dentures improperly may fall under this category. You should contact your local small claims court (other in person or online) and look into whether you could bring this action there, where you would not need an attorney and where the costs are low (typically, $30 - $50 to file the case). Good luck.