Overview
Chronic apical periodontitis (CAP) is the most prevalent periapical pathology — a low-grade, persistent inflammatory reaction of periradicular tissues to bacterial products from a necrotic infected root canal. Unlike its acute counterpart, CAP is typically asymptomatic, discovered incidentally on radiographs as the characteristic periapical radiolucency.
The periapical lesion in CAP is predominantly a granuloma (75–85% of lesions) — a mass of chronically inflamed granulation tissue containing macrophages, lymphocytes, plasma cells, and fibroblasts — or a radicular cyst (15–25%) — an epithelium-lined pathological cavity containing fluid or semi-solid material.
The biological debate over whether periapical cysts can heal with non-surgical root canal treatment or require surgical enucleation has evolved with CBCT evidence showing that most lesions, regardless of histological type, resolve after adequate endodontic therapy.