Observations on a calcium hydroxide lining in retrieved deciduous teeth, with proximal amalgam fillings

The integrity and thickness of Dycal linings were determined on exfoliated deciduous teeth in which proximal fillings had been placed in vivo. The teeth remained in the oral cavity for more than 18 months after placement of the restorations. The average lining thickness was found to be 114 microns. One-third of the samples showed evidence for the presence of Dycal at the gingival floor, up to the proximal tooth wall. Wash-out of the lining was observed for most teeth in which Dycal had been present near the proximal tooth wall. Incipient caries formation, associated with wash-out of the lining, was noted in a few samples. Contact between amalgam and dentine was frequently observed at the line angle, pulpal floor and axial wall.