In U.S. Patent 7,649,029, 3M Innovative Properties Company (St. Paul, MN) reveals improved ionomer dental compositions containing nanozirconia fillers. The compositions can be used in a variety of dental and orthodontic applications, for example, as adhesives, cements, restoratives, coatings and sealants, according to inventors Brant U. Kolb, Hoa T. Bui, Jason P. Thalacker, Lani S. Kangas, Joel D. Oxman, Kenton D Budd, Jacqueline C. Rolf and Sumita B. Mitra.
The restoration of decayed dental structures including caries, decayed dentin or decayed enamel, is often accomplished by the sequential application of a dental adhesive and then a dental material (e.g., a restorative material) to the relevant dental structures. Similar compositions are used in the bonding of orthodontic appliances (generally utilizing an orthodontic adhesive) to a dental structure. Often various pretreatment processes are used to promote the bonding of adhesives to dentin or enamel. Typically, such pretreatment steps include etching with, for example, inorganic or organic acids, followed by priming to improve the bonding between the tooth structure and the overlying adhesive.
3M’s compositions features stable ionomer compositions containing nanozirconia fillers that provide the compositions with improved properties over previous ionomer compositions. In particular, the inclusion of one or more nanozirconia fillers provides ionomer systems that are optically translucent and radiopaque. The nanozirconia is surface modified with silanes to aid in the incorporation of the nanzirconia into ionomer compositions, which generally contain a polyacid that might otherwise interact with the nanozirconia causing coagulation or aggregation resulting in undesired visual opacity.
The 3M nanocompositions will compete with a variety of dental and orthodontic adhesives, cements, and restoratives that are currently available. Compositions including fluoroaluminosilicate glass fillers (also known as glass ionomer or "GI" compositions) are among the most widely used types of dental materials. These compositions have a broad range of applications such as filling and restoration of carious lesions; cementing of, for example, a crown, an inlay, a bridge, or an orthodontic band; lining of cavity; core construction; and pit and fissure sealing. 3M’s nanozirconia filler compositions overcome many of the shortcoming associated with glass fillers such as problems of mixing and adhesion.
