Fig. 2
The histopathological images show periapical granuloma in tissues from the healing and non-healing groups: Healing group (A–C): A the granulation tissue with prominent blood vessels showed mixed inflammatory infiltrate comprising of histiocytes, lymphocytes, and plasma cells, can be labeled as an intermediate stage of periapical granuloma. (Hematoxylin and Eosin (H & E); original magnification × 400). B The periapical granuloma with intense inflammation (numerous neutrophils). In addition, the granulation tissue with prominent foamy macrophages and blood vessels can be seen, can be labeled as an early stage of periapical granuloma. (H & E; original magnification × 400). C The granulation tissue showed mixed inflammatory infiltrate comprising of histiocytes, lymphocytes, and plasma cells. In addition, the brown areas represent hemosiderin pigmented fibrous stroma with prominent fibroblasts are also seen which characterize as a late stage of periapical granuloma. (H & E; original magnification: × 400). D The histopathological image of no healing group: Periapical granuloma with fibrous connective tissue with a significant number of fibroblasts and infiltration of inflammatory cells (few plasma cells and histiocytes). (H & E; original magnification: × 400)