An histological study of cystic lesions following pulp therapy in deciduous molars.

The clinical and radiographic features of a group of apical periodontal cysts associated with endodontically treated deciduous molar teeth have been previously reported. The histological description and histochemical investigation of distinctive intraepithelial inclusions are described in this paper. The chronic inflammatory response is dominated by plasma cells and the wall contains an amorphous, eosinophilic material that is shown to contain phenolic groupings similar to those present in the intracanal medicaments used clinically. A direct relationship is proposed between the inclusions, continued antigenic stimulation within the lesions and their clinical behaviour.