Legal Question in Legal Ethics in Illinois

Unclear for many reasons, including why you suddenly lost trust in him. While I would not recommend using that as a reason, have you asked? And it depends on the "procedure". For example, if the dentist said you need a crown and the dentist already prepared the tooth, took the needed mold and has ordered the crown, full or partial payment was most likely already due so it may not be "in advance" and you could be considered in "breach". If no work has been performed, however, that may be a different story.