The protective effect of zinc on rosin and resin acid toxicity in human polymorphonuclear leukocytes and human gingival fibroblastsin vitro

Abstract

Combinations of rosin and zinc are used in dentistry as components of periodontal dressings and cements and as root canal sealers. The composition and properties of rosins differ largely depending on source and refinement processes. Rosin (colophony) is composed of approximately 70% resin acids. In order to study the toxic effects of different natural rosins and purified resin acids and the detoxifying effects of zinc, these compounds were analyzed and tested on human polymorphonuclear leukocytes (PMN cells) and human gingival fibroblasts using the radiochromium release method. The rosins and the pure resin acids showed a strong dose-related cytotoxicity, which was inhibited by increased zinc concentrations. The purified resin acids (isopimaric, levopimaric, and neoabietic acid) were more toxic than the natural rosins. The contents of these resin acids might explain the difference in toxicity of the rosins tested. It is concluded that rosin and zinc are not to be considered inert compounds and that the cytoprotective effects of zinc and its role in dentistry products merit further investigations.

Cytotoxicity Testing of Temporary Luting Cements with Two- and Three-Dimensional Cultures of Bovine Dental Pulp-Derived Cells

“…Combinations of rosin and zinc are used in dentistry as components of periodontal dressings and cements and as root canal sealers. Sunzel et al [31] showed that rosins and pure resin acids had a strong dose-related cytotoxicity that was inhibited by increased zinc concentrations. These materials showed cytotoxic effects in this study as well.…”

Laboratory evaluation of the physicochemical properties of a new root canal sealer based on Copaifera multijuga oil‐resin

“…Zinc oxide, which corresponds to 27.89% of the sealer, is an efficient antimicrobial agent and has been shown to have a cytoprotector effect on cells (Sunzel et al. 1997) and also participates in the sealer radiopacity.…”

“…It also gave good radiopacity to Biosealer, better than barium sulphate, with the advantage of having a lower risk of toxicity, because bismuth is considered a less toxic heavy metal (Sano et al 2005). Zinc oxide, which corresponds to 27.89% of the sealer, is an efficient antimicrobial agent and has been shown to have a cytoprotector effect on cells (Sunzel et al 1997) and also participates in the sealer radiopacity. Calcium hydroxide, which corresponds to 27.89% of the sealer, has a role in setting, as it participates in the acid-base reaction between the basic components of the sealer powder and the acid constituents of the oil-resin (Ribeiro 1984).…”

Microscopic analysis of subcutaneous reactions to endodontic sealer implants in rats

“…Contrary to Endofill, Endomethasone does not contain hydrogenated resin. Sunzel et al35 showed that when these resins are added to dental sealers, they cause a greater cytotoxic effect.…”