THE EFFECT OF A LIGHT-CURED PERIODONTAL DRESSING MATERIAL ON HELA-CELLS AND FIBROBLASTS IN-VITRO

THE EFFECT WHICH A VISIBLE LIGHT-curing periodontal dressing material based upon a urethane dimethacrylate resin has upon HeLa cells and fib roblasts in its uncured and fully cured stales has been studied in vit ro. Fully-cured material has no effect on either cell type. Uncured ma terial produces a surrounding zone of growth inhibition and cell death on direct contact. Inhibition is caused by the release into the mediu m of substances toxic to cells. However, this growth inhibition is ove rcome in time (5 days). It is suggested that partly-cured material con taining residual free monomer in contact with a healing gingival site could impede rapid repair. Nuclear magnetic resonance microimaging has shown that in places where there is a greater depth of material (e.g. , interproximal regions) this underlying material may be partly cured. Increasing the exposure to the curing light will prevent (or minimize ) the presence of partly-cured material; the fully-cured material bein g compatible with the cells.