Foreign body gingival lesions: distribution, morphology, identification by X-ray energy dispersive analysis and possible origin of foreign material

BACKGROUND: Foreign material may cause and aggravate gingival lesions. This is rarely considered clinically. The lesions are resistant to frequently protracted conventional therapy. The foreign material is often inconspicuous and easily overlooked by the pathologist. METHODS: 85 cases of gingival lesions containing foreign material were investigated by conventional and polarization light microscopy, focusing on the morphology and optical characteristics of the foreign substance. Supplemented with the results of X-ray energy dispersive analysis the foreign material was compared with commonly used dental materials. RESULTS: The foreign material was most frequently compatible with amalgam. Inconspicuous crystals, often revealed only by polarization microscopy, were most commonly compatible with abrasives, particularly corundum and silicates, and mostly occurred together with amalgam dust. CONCLUSIONS: Iatrogenic introduction of dental materials during dental procedures explains most foreign body gingival lesions which could be reduced or avoided by prophylactic measures. Pathologists should meticulously scrutinize gingival biopsies routinely applying polarization microscopy.