malpractice dentist and dental company

I am not sure from your question that this is medical (dental) malpractice. Your post is a bit unclear to me. The dentist quit doing the procedure on you or the dentist quit the practice? If the former, what reason was given to you as to why the dentist quit doing the procedure and specifically, what procedure was being performed and why was it necessary? If it is the latter issue, certainly wouldn't someone else within the practice be able to take over the treatment of your case? Further, unless you were permanently damaged in some way as a result of what the denitst did, you probably wouldn't have a viable claim anyhow. The statute of limitations in Wisconsin to sue for professional medical malpractice is three years. Failure to file a lawsuit within 3 years from the date of the occurrence, would forever bar your claim.