Nanocomposites and nanoionomers for orthodontic bracket bonding

Abstract In day-to-day clinical practice, it is essential to obtain a reliable bond between an orthodontic attachment and the tooth enamel. Traditionally, dental (restorative) composite materials have been used for orthodontic bonding. Dental composites are composed of mainly organic synthetic polymer matrices, inorganic fillers, and silane coupling agents that bond the reinforcing fillers to the polymer matrix. The overall mechanical and physical behaviors and clinical performance of the composite resins are largely governed by the size, quantity, and distribution of the filler particles incorporated in the matrix. In conventional dental composites, the filler particle size ranges from mega, to mini, to microfillers. When the inorganic filler particle size in a composite resin becomes nanosized, they are called nanocomposites. When the filler content of resin-modified glass ionomer cements (RMGIC) is replaced with the formulation based on bonded nanofiller technology, it is called a nanoionomer. In this chapter, the physical properties and clinical applications of nanocomposites and nanoionomers in orthodontic bonding are discussed.