Methods and kits of materials and supplies for forming a dental prosthesis by an injection molding process in situ in a patient's mouth so as to correct the imperfect teeth of the patient's dentition. The imperfect teeth are corrected by injection molding the dental prosthesis in situ in the patient's mouth using a mold of a corrected model of the patient's dentition placed over the imperfect teeth. Adjacent teeth are covered with a polymer release material prior to injection molding of teeth to be corrected, such that the teeth to be corrected have at least one tooth between them draped with the polymer release material to provide a space adjacent to each of the corrected teeth. The corrected teeth are then covered with the polymer release material in a second round of treatment to complete the procedure on the remaining teeth.