Хронический апикальный периодонтит
Prevalence: Found in 20–50% of root-filled teeth on radiographic surveys; extremely common incidental finding
Overview
Бессимптомное периапикальное разрушение — образование гранулёмы и кисты у верхушки корня
Etiology
Chronic apical periodontitis develops when the host-pathogen balance in an infected root canal establishes a stable, low-grade equilibrium. Bacteria in the apical portion of the root canal system continuously release antigens that provoke periapical inflammation, but the immune response contains rather than eliminates the infection.
Intraradicular biofilm dominates the microbiology — polymicrobial communities with Fusobacterium, Prevotella, Actinomyces, Streptococcus, and others form robust biofilms on canal walls, in ramifications, isthmuses, and accessory canals that resist irrigation and instrumentation.
Extraradicular infection (biofilm on root surfaces, periapical actinomycosis) accounts for a minority of persistent lesions but is critical to recognize as it does not respond to non-surgical treatment. Periapical actinomycosis — Actinomyces species forming sulfur granules visible histologically — is the classic example.
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Pathogenesis
Radicular granuloma formation is a classic Type IV (delayed-type) hypersensitivity response. Persistent antigen stimulation drives macrophage accumulation and epithelioid transformation. Lymphocytes, plasma cells, and fibroblasts proliferate; new blood vessels form (angiogenesis); and the lesion becomes encapsulated in fibrous tissue.
Classification
Periapical Granuloma
Granulation tissue mass without epithelial lining; most common (75–85%)
Radicular Cyst
Epithelium-lined cystic cavity; formed by Malassez epithelial rests proliferation
Clinical Manifestations
Chronic apical periodontitis is primarily a radiographic diagnosis. The vast majority of patients are completely asymptomatic — no pain, no swelling, no sensitivity to biting. The lesion is discovered incidentally during routine dental radiographs or investigation of adjacent teeth.
Diagnosis
Periapical radiographs reveal the characteristic periapical radiolucency — ranging from subtle widening of the PDL space to a well-defined, corticated radiolucent lesion (suggesting cyst) or a diffuse, poorly-defined radiolucency (suggesting granuloma). The radiographic appearance does NOT reliably distinguish granuloma from cyst histologically.
Treatment Protocol
Non-Surgical Root Canal Treatment
First-line treatment; achieves healing in 85–95% of granulomas and many cysts
Prognosis
Non-surgical root canal treatment achieves periapical healing in 85–95% of teeth without previous root canal treatment. For retreatment of previously filled teeth with persistent lesions, success rates range from 65–80%. Large lesions (>10mm) and true radicular cysts have lower healing rates with non-surgical treatment alone.
Prevention
- Adequate coronal seal after root canal treatment to prevent re-infection
- Timely crown placement after root canal treatment (within 3 months)
Interactive Quiz
Test your understanding of Хронический апикальный периодонтит.
Q1.
3D Pathology Description
Three-panel visualization: Panel 1 — periapical granuloma cross-section showing the layered architecture: necrotic canal center (dark grey) → bacterial biofilm on root surface (violet layer) → fibrous capsule (dense grey band) → central granuloma tissue (pink/red with cellular dots representing macrophages, lymphocytes, plasma cells) → peripheral bone with active osteoclasts (orange). Panel 2 — radicular cyst formation: same root but with epithelial lining (thin pink layer) → cyst lumen filled with clear fluid containing cholesterol crystal formations (angular yellow reflective shapes) → inflammatory cells in cyst wall. Panel 3 — healing after root canal treatment: progressive bone fill animation over 18 months, show cancellous trabeculae regenerating from periphery inward as time slider advances. In all panels, animate Malassez cell rests in PDL as small green clusters that proliferate into cyst lining when stimulated. Include CBCT-style cross-sectional view option showing lesion in axial, coronal, and sagittal planes simultaneously.