title: Crystal growth by restorative filling materials.
abstract: This study examined the activity and ability of materials to mineralize teeth in gaps, simulating microleakage between the materials and teeth. Three restorative materials (two glass ionomer cements and a compomer) were used in this study. Cured disks of restoratives were placed over flat human tooth surfaces (enamel and dentin), separated by a standardized 20-μm interfacial space, and stored in water for 24 h or 1 yr. After the water-storage period, the materials were detached from the teeth and the opposing surfaces were examined by scanning electron microscopy (SEM) and electron probe micro analysis (EPMA).Hemispherical-shaped precipitations, composed of minute semicircle plate-like crystals, were observed by SEM on the enamel surface after 1 yr of water storage for glass ionomer cement. The amount of crystal growth with the chemical-cured type of glass ionomer cement was greater than with the dual-cured type of glass ionomer cement. However, there was no crystal formation in the compomer. Moreover, no structural changes were observed on dentin surfaces for any material in water after 1 yr. The elements detected in the crystals by EPMA were calcium (Ca), phosphorus (P), and aluminum (Al). The two glass ionomer cements tested have the ability to induce crystals whose composition might be derived from cured glass ionomers.
authors.affiliation: Division of Biomaterials and Bioengineering, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Endo
authors.forename: Masanori
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Haraguchi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ohno
mesh_terms: D020770:Compomers; D003460:Crystallization; D003743:Dental Enamel / Q000648:ultrastructure; D003763:Dental Leakage / Q000517:prevention & control*; D003793:Dental Restoration, Permanent / Q000379:methods*; D003804:Dentin / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D005899:Glass Ionomer Cements; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008855:Microscopy, Electron, Scanning; D055116:Self-Curing of Dental Resins
chemical_list: D020770:Compomers; D005899:Glass Ionomer Cements