In any case involving a conservatorship, guardianship of the estate or testamentary trust in which it appears to the court that the fiduciary has neglected or refused to complete such matter, and the appointment of a successor fiduciary would serve no useful purpose, the court may hold a hearing, after giving public notice thereof and such other notice as the court deems reasonable. Thereafter, on its own motion, the court may order and decree the matter closed for dormancy and the bond released without adjudication, provided the bond shall be released for future acts and not for any acts or misdeeds occurring prior to the closing of the matter. The matter shall be reopened only by further order of the court.