Do I have a case if a dentist left a piece a metal and a small rubber piece in my gum that was removed in 2019 which this may has been why I was misdi

More details would be needed in order to evaluate whether you have a claim.  Your brief description does, however, raise a concern that the statute of limitations may have expired.  In Pennsylvania, there is a 2 year statute of limitations.  There are some limited circumstances which could suspend the commencement of the limitation period, but your description does not provide enough details to assess this issue.  You may want to talk with a lawyer.