Once an adoption proceeding in the juvenile court has been completed, a copy of all the juvenile court records, including filings and documents originally sent upon transfer by the probate court, shall be forwarded to the probate court from which the case was transferred. All other filings and documents that are retained by the juvenile court pertaining to the adoption proceeding shall be sealed, kept as a permanent record of the court, and withheld from inspection except as otherwise ordered by the court for good cause shown.