Studies Related to the Discoloration in the Surrounding Gingiva of Fixed Prosthesis

Part 1. Analysis of Clinical and Experimental Findings

Abstract

Localized gingival discoloration can sometimes be observed around fixed prosthesis, and our main objective was to investigate those clinical findings where gingival discolorationswere thought to be caused by cast core preparations. Gingiva of dogs were used to clarify the mechanismof this type of discoloration.
Clinical findings revealed large amounts of granular pigmentations within the lamina duraregion of the gingiva, and chemical tests revealed silver sulfate to be the main substance.
Experimental findings showed the cause of discoloration to be due to metal fragmentationsflying into the subgingival region around the tooth abutment during the cast core preparation.The metal fragmentations, after remaining in the lamina dura region for a period of 4 weeks, can be observed through the epithelial membrane, but not to the extent of those found in theclinical findings. Metal fragmentations were also found to be fairly large with inflammatory Cellinfiltration within the surrounding gingival region. Chemical analysis also revealed amounts ofsilver, but no traces of silver sulfate.