Penetration of ions from silicate cement restorations into Copalite® - covered cavity walls

Abstract

Tveit, A.B. & Hals, E. Penetration of ions from silicate cement restorations into Copalite©-covered cavity walls. Acta Odont. Scand. 36, 15–24 This study aimed to assess the effect of silicate cement on Copalite®-covered cavity walls in extracted human teeth. Class V cavities were prepared in 24 premolars and filled with silicate cement (Bio-Trey®). Four cavities were unlined, the rest of the cavities were lined with 1 or 2 layers of Copalite before insertion of the restorations. After 6 months, 70-100 μm thick longitudinal sections of the teeth were studied by polarized light microscopy, microradiography and electron probe microanalysis. When imbibed in water or quinoline, a subsurface zone of altered birefringence was noticed in nearly all cavity walls. Nearly half of the cavit walls in the experimental groups showed a surface zone of increased radiopacity. In a few instances a subsurface radiolucent zone was present. By electron probe microanalysis F (0,4-3% by weight), Zn (14%) and Al (0,2-6%) were measured in the outer 10–60 μm of the cavity walls. The study shows that even with a double layer of Copalite, known to prevent microleakage, a desirable uptake of F and A1 from silicate restorations into cavity walls can take place. Copalite does not prevent a phosphoric acid effect on the cavity walls.