Differential induction of surface chemical compositional change on tooth structure by glass ionomer restorative materials.

Glass ionomer cement (GIC) is a restorative dental material capable of promoting mineral deposition on surrounding tooth substrates. However, it is unclear as to whether demineralization and remineralization due to an oral pH change of the tooth affect the dissolution pattern of tooth crown and root differently. It also remains to be elucidated how GIC alters superficial chemical compositions of tooth crown structurally known as enamel, in relation to the root. In this study, we investigated an effect of pH challenge on chemical compositional change of tooth crown and root, as well as the contribution of GIC restorations on a shift of elemental abundance on tooth crown and root. Our findings demonstrated that an exposure to a pH cycling resulted in a drastic change of elemental profile of the root, but not the crown. Modification of superficial elemental ingredients of GIC-restored cavities located on different anatomical part of the tooth was found after an acid attack. Notably, a differential induction of chemical compositional shift was dependent on the type of GIC used and the location of restored GIC. Our study highlights a susceptibility of root portion to acid-induced elemental dissolution, and that GIC use might be implicated in the delayed dissolution rate of the tooth structure.