The present invention relates to a deagglomerated glass filler for sustained ion release for imparting ion sustained-release property to a dental material for use in the dental field. The dental material means a material for use in filling, prosthetic repair, temporary sealing, temporary bonding, preparation of a prosthetic appliance, adhesion/luting, pit and fissure sealing, or the like in a dental treatment. A glass filler for sustained ion release that sufficiently continuously releases a metal ion present in a glass composition as compared with a conventional glass filler for sustained ion release has been demanded in the field of a dental material. Such an object is achieved by a glass filler for sustained ion release that is obtained by performing a silane compound treatment step and an acidic polymer treatment step and that is controlled to satisfy a specific D50 particle size relationship in each of the steps.
