Periapical Tissue Diseases Overview

Disease of Periapical Tissue

• Periapical area: The area surrounding the apical foramen of a dental root.
• Periapical Lesions: Inflammation surrounding the apical foramen of the dental root.
• Etiology of Periapical Lesions:
  • Pulpitis
  • Traumatic Injury
  • Deep-seated restorations
  • Infection through gingival crevice (periodontal diseases)
  • Use of unsterilized instruments during root canal treatment
  • Application of strong chemical antiseptics during root canal treatment

Periapical Periodontitis

• Inflammation of the periodontal ligament (PDL) around the apical portion of the root.
• Types:
  • Acute periapical periodontitis
  • Chronic periapical periodontitis

Acute Periapical Periodontitis

• Painful inflammation of the periodontium due to trauma, irritation, or infection through the root canal.
• Also called symptomatic apical periodontitis.
• Tenderness on percussion, severe pain causing difficulty closing teeth.

Etiology (Causes)

• Vital tooth:
  • Occlusal trauma
  • Wedging of foreign body
  • Blow to the teeth
  • Orthodontic pressure
• Non-vital tooth:
  • Sequelae of pulpitis
  • During root canal therapy (forcing irrigating irrigants or medicaments through the apical foramen)
  • Extension of obturating material
  • Perforation of the root
  • Overinstrumentation

Clinical Features (Symptoms)

• Hot or cold substances do not cause pain
• Slight extrusion of the tooth from its socket
• Tenderness on mastication due to inflammatory edema in the PDL
• Severe pain due to external pressure forcing edema fluid against sensitized nerve endings
• Tender to percussion (preapical test).
• Widening of the PDL space (radiographic feature).

Histopathological Features

• Acute apical periodontitis characterized by an inflammatory reaction with engorged blood vessels and neutrophil accumulation.
• This inflammation is often transient if caused by acute trauma
• Progress to bone resorption if irritant not removed.
• Abscess formation possible with bacterial infection(acute preapical abscess/alveolar abscess)

Treatment

• Selective grinding if inflammation is due to occlusal trauma
• Extraction or root canal treatment (RCT) to drain exudate.

Acute Periapical Abscess (Dentoalveolar Abscess)

• An acute suppurative process in the dental periapical region.
• Accumulation of acute inflammatory cells at the apex of a non-vital tooth.
• Etiology:
  • Infection (following pulpitis, hematogenous spread)
  • Traumatic injury
  • Pulp necrosis
  • Mechanical/chemical manipulation in RCT
• More commonly, exacerbation of a chronic infection (e.g., periapical granuloma, "phoenix abscess").

Clinical Features for Acute Periapical Abscess

• History of pain (due to previous pulpitis)
• Large carious cavity/filling usually present
• Thermal stimulation does not cause pain (due to pulp necrosis)
• Tooth extremely painful and sensitive to percussion
• Tooth slightly extruded from its socket
• Intense throbbing pain as pus forms
• Systemic manifestations: Red and tender gingiva around the affected root, no swelling (inflammation confined within bone), lymphadenitis and fever possible

Radiographic Features

• Amorphous radiolucent area with irregular faintly margined borders in the periapical area of the dental root.

Histological Features of Acute Periapical Abscess

• Dense, almost solid masses of neutrophils (pus cells)
• Intermingling with inflammatory exudate, cellular debris, necrotic material, bacterial colonies, or histiocytes
• Dilated blood vessels in the PDL and bone marrow space
• Inflammatory infiltration of the bone marrow
• Resorption and degeneration of osteocytes (bone cells)

Complications of Untreated Periapical Abscess

• Pus may discharge directly into the oral cavity (sinus tract).
• Pus tracking palatally forming a palatal abscess
• Abscesses in molar regions penetrating buccal cortical plate
• Inflammatory edema and suppuration spreading into surrounding soft tissues (face, neck, cellulitis)
• Abscesses may drain through skin surface.
• Perforation of bone above tooth attachments, potentially leading to the eye or upper lip.
• Potential discharge into the maxillary sinus
• Potential involvement of sublingual, submandibular, and lateral pharyngeal spaces.

Cellulitis

• Diffuse inflammation of soft tissues, tending to spread through tissue spaces and fascial spaces .
• Clinically: painful, swelling of involved soft tissues, malaise, elevated temperature, trismus (difficulty opening mouth), swelling due to inflammatory edema, suppuration and abscess formation.
• Potential eye involvement is a serious concern (potential cavernous sinus thrombosis)
• Etiology is often related to spreading infection.

Chronic Periapical Abscess

• Features: May be a chronic condition or a sequela of acute infection. No acute symptoms, but tooth is felt high in socket, intraoral sinus formation, possible salty taste.
• Microscopically: Pus cavity with chronic inflammatory cells, lymphocytes, plasma cells, macrophages; fibrous tissue and capillaries are present; a fibrous capsule at the periphery

Periapical Granuloma

• Localized granulation tissue mass surrounding the apical foramen of a non-vital tooth; most common periapical lesion.
• Resulting from pulp death and diffusion of bacterial toxins from root canals into surrounding periradicular tissue (through apical and lateral canals).
• Possible presence of lateral/accessory root canals leading to lateral granuloma
• Treatment typically involves apicectomy and root canal treatment.

Chronic Periapical Periodontitis

• Occurs as a result of pulp death; diffusion of bacterial toxins from the root canals into the surrounding periradicular tissue occurs through apical and lateral canals.
• Most common periapical lesion.
• Chronic periapical inflammation characterized by granulation tissue.

Osteomyelitis

• Acute or chronic inflammatory process in bone marrow spaces or cortical surfaces; usually bacterial infection.
• Classification includes acute suppurative, chronic suppurative, chronic low-grade (sclerosing), focal sclerosing, and proliferative periostitis.
• Etiology includes dental infection, jaw fracture, or hematogenous spread.
• Predisposing factors include radiation damage, Paget's disease, osteoporosis, and systemic diseases (e.g., malnutrition, acute leukemia, uncontrolled diabetes, sickle cell anemia, chronic alcoholism).
• Acute osteomyelitis: Rapidly destructive inflammatory process; virulent bacterial strains commonly cause acute spreading of inflammatory process through medullary spaces in bone
• Acute osteomyelitis pathogenesis, pathology: inflammation, exudate spread, vascular thrombosis, necrosis, bacterial pus-filled pockets, lifting of periosteum (worsening necrosis) and osteoclastic activity (bone resorption).

Chronic Osteomyelitis

• Often a sequella of acute osteomyelitis.
• Characterized by a persistent low-grade infection, bone destruction, and granulation tissue formation, with little suppuration.
• Local bone sclerosis is more likely than in acute osteomyeliti.s and it is less likely to cause rapid spread of infectious agents
• Common sites are posterior mandible, and the disease process is characterized by low-grade pain, bad taste from pus, swelling with increased pain and discharge , along with increased mobility of affected teeth in some cases.

Diffuse Sclerosing Osteomyelitis

• Chronic low-grade inflammation of bone
• Occurs as a response to a low-grade stimulus
• Pathogenesis; bacterial infection causing formation of a mass of chronically inflamed granulation tissue, which then results in sclerosis of surrounding bone with dense bone trabeculae and fibrotic marrow tissue (infiltrated by a small number of lymphocytes and plasma cells).
• Clinical features; usually asymptomatic adults, commonly involves the mandible

Focal Sclerosing Osteomyelitis

• Focal bony reaction to low-grade periapical infections or pulpal inflammation
• Primarily affects children and young adults
• Usually asymptomatic
• Radiographically, often associated with a narrowed periodontal space or periapical area , which is denser then the surrounding bone
• Pathology; characterized by a dense mass of sclerotic bone trabeculae, scanty fibrotic marrow tissue, with an infiltration of a small number of lymphocytes and plasma cells.

Chronic Osteomyelitis with Proliferative Periostitis (Garré's)

• Characterized by hard bony swelling around the jaw, often at the periphery
• Essentially periosteal osteosclerosis with reactive vital bone expanding the surface of affected bone
• Primarily children and young adults
• Radiographically shows duplication of the hard cortex - known as onion skin appearance
• Histologically, shows a supra-cortical but subperiosteal mass of parallel layers comprised of reactive new bone or osteoid. Connective tissue usually fibrous, with occasional lymphocycte and plasma cells patches.