Effect of zinc upon cell attachment and proliferation on periodontally-diseased root surfaces

The purpose of this study was to determine the effect of zinc ions on fibroblast attachment to periodontally-diseased root surfaces in vitro. Extracted periodontally-diseased teeth were treated with 0.5% ZnCl2 by iontophoresis at 0.5 mA for 2 to 6 minutes. Control groups were untreated diseased and untreated healthy teeth. Sections of the root underlying the pocket were cut from the diseased teeth. The specimens were incubated for 18 hours with L929 mouse fibroblasts, then transferred and incubated in cell-free medium for 48 hours. Cell attachment was evaluated by cell counts and scanning electron microscopy (SEM). Root surfaces were sampled with an acid-etch technique and zinc was measured with an atomic absorption spectrophotometer. Two samples from each group were examined for cell attachment with SEM. Data were analyzed using the appropriate statistical methods. The results showed that diseased, untreated root surfaces had significantly fewer cells attached; however, zinc iontophoresis did not significantly improve cell attachment to the diseased root surfaces. Zinc analysis showed that diseased, untreated root surfaces had a higher zinc content than healthy ones. SEM examination showed striking differences in cell attachment to healthy versus diseased root surfaces. The data indicated that zinc iontophoresis did not significantly enhance cell attachment to root surfaces of diseased teeth.