· Sequalae of acute periapical periodontitis
· Ultimate resault of chronic periapical periodontitis-due to acute inflammation that has been inadequately drained and incompletely resolved.
· tooth is usually non vital
· First recognized as rounded area of radiolucency at the apex of the tooth-usually 5mm in diameter and well defined margins.
· Interprited as early cyst formation.
· Chronic periodontitis is typical chronic inflamation characterized by lymphocytes,plasma cells and macrophages.
· Infection is confined by inflammatory cells and granulation tissue surrounds the area.the granulation tissue grows into rounded mass forming granuloma.
· Osteoclasts resorb the bone to accomadate it.
· Spontaneous healing is absent due to tunnel of continuous infection in the root canal
· Variable degrees of proliferation of the epithelial rests of Malaassez in a periapical granuloma at the apex of the dead tooth are common.Epithelial proliferation may be sufficient to lead ultimately to cyst formation