The interfacial region of the tooth/glass ionomer restoration: a confocal optical microscope study

The dynamic interactions between the tooth tissues and a glass ionomer cement were investigated, using fluorescent markers incorporated into components of glass ionomer restorations. A confocal optical microscope was used to examine the tooth/restoration interface. Samples were examined at specific intervals after restoration to determine the effect of maturation of the glass ionomer matrix. Loss of fluorescent dye from the glass ionomer restoration into the subjacent dentin indicated fluid movement across the interface during maturation. To determine the effect of shrinkage from water loss on the integrity of the tooth/restoration interface, restored teeth were maintained fully hydrated and then allowed to dry. Substantial cracking at the enamel margins after drying of the set restoration indicated the strength of the attachment to enamel and also cautioned against excessive clinical drying.