AtlasDentalPeriapical Abscess

Dental Diseases

Periapical Abscess

aka Dental Abscess · Dentoalveolar Abscess · Apical Abscess

Localised collection of pus at the root apex resulting from pulp necrosis and bacterial infection.

Acute
Pain, swelling, systemic signs
Chronic
Sinus tract, minimal symptoms
Treatment
Drainage + RCT/extraction

Red Flags

  • ·Trismus
  • ·Dysphagia
  • ·Dyspnoea
  • ·Floor of mouth elevation
  • ·Fever >38.5°C

§ figuresFigures (4)

Fig. 1A root showing an abscess at the apex after extraction.

“Periapical abscess” · lacihobo · CC BY-SA 4.0 · Wikimedia Commons

Verified open-access images only, reproduced for education under their stated licences · no AI-generated or illustrative artwork · Periapical Abscess figures pending faculty review.

§ overviewOverview

Acute or chronic suppurative process at the periapex secondary to non-vital pulp.

§ icdICD Classification

K04.7

§ etiologyEtiology

  • 01Sequela of untreated caries/pulpitis
  • 02Trauma
  • 03Failed RCT

§ epidemiologyEpidemiology

Common; major cause of dental emergency visits.

§ pathogenesisPathogenesis

Pulp necrosis → bacterial proliferation → PMN accumulation → pus formation → bone resorption → intra/extra-oral sinus if untreated.

§ clinicalClinical Features

  • 01Acute: severe throbbing pain, tooth elevation ('high tooth'), swelling, fever
  • 02Chronic: sinus tract (parulis), mild discomfort or asymptomatic

§ signsSigns & Symptoms

  • 01Tender to percussion
  • 02Mobility
  • 03Regional lymphadenopathy
  • 04Fluctuant swelling

§ differentialDifferential Diagnosis

  • 01Periodontal abscess
  • 02Pericoronitis
  • 03Osteomyelitis
  • 04Lateral periodontal cyst

§ radiographicRadiographic Features

  • 01Widened PDL space (acute)
  • 02Periapical radiolucency (chronic)

§ investigationsInvestigations

  • 01Vitality tests (negative)
  • 02PA radiograph
  • 03Aspiration if fluctuant

§ treatmentTreatment

  • 01Establish drainage: access opening or I&D
  • 02RCT or extraction
  • 03Antibiotics if spreading infection / systemic signs

§ medicalMedical Management

  • 01Amoxicillin 500 mg TDS × 5 days
  • 02Metronidazole add-on for anaerobes
  • 03Analgesics

§ complicationsComplications

  • 01Cellulitis
  • 02Fascial space spread
  • 03Ludwig's angina
  • 04Cavernous sinus thrombosis
  • 05Sepsis

§ prognosisPrognosis

Excellent with drainage and definitive treatment.

§ examKey Examination Points

  • 01Drainage is paramount; antibiotics without drainage fail
  • 02Chronic abscess = radiolucency + sinus tract
  • 03Extraction if non-restorable

§ revisionQuick Revision Summary

  • 01Incision and drainage principle
  • 02Parulis = chronic sinus tract
  • 03Antibiotics adjunctive, not primary

§ vivaBDS Viva Questions

  • 01How do you differentiate periapical from periodontal abscess?
  • 02What is the significance of a sinus tract?
  • 03When are antibiotics indicated?

§ mcqsMCQs — Assessment (3)

Question 1

Most important initial treatment for periapical abscess:

Question 2

A 'gum boil' (parulis) indicates:

Question 3

Radiograph of acute periapical abscess may show:

§ evidenceReferences & Evidence

Current Classification

WHO Classification of Tumours Online — Head and Neck

IARC / WHO · 2022

Continuously updated online edition of the WHO head and neck tumour classification.

View official source

Evidence summary

Highest level of evidence linked to this page: WHO / Official Classification.

  • L1 · Classification — 1
  • L6 · Textbook — 3

1 linked source was published from 2024 onwards. Where guidance is limited or contested, rely on the higher-level sources above rather than this summary. Educational use only — not a substitute for clinical judgement.

Content last reviewed

September 2026

Evidence last reviewed

September 2026

Next scheduled review

September 2027

Review status

EVIDENCE REVIEWED

Search latest PubMed evidence

Last literature search: 7 September 2026

Open PubMed

Current Classification

Reference #1L1 · ClassificationWHO / Classification Verified
WHO Classification of Tumours Online — Head and Neck

IARC / WHO. IARC · 2022

Continuously updated online edition of the WHO head and neck tumour classification.

DOI: Identifier not availablePMID: Identifier not available
View source

Histopathology References

Reference #4L6 · TextbookHistopathology References Unverified
Surgical Pathology of the Head and Neck3rd Edition

Barnes L. CRC Press · 2008

Detailed histopathological reference for head and neck diagnostic criteria.

DOI: Identifier not availablePMID: Identifier not available

Textbook References

Reference #2L6 · TextbookTextbooksRecent Verified
Oral and Maxillofacial Pathology5th Edition

Neville BW, Damm DD, Allen CM et al.. Elsevier · 2024

Standard reference textbook of oral and maxillofacial pathology used throughout this atlas.

DOI: Identifier not availablePMID: Identifier not available
View source
Reference #3L6 · TextbookTextbooks Unverified
Shafer's Textbook of Oral Pathology9th Edition

Rajendran R, Sivapathasundharam B. Elsevier · 2020

Undergraduate and postgraduate oral pathology textbook widely used in BDS and FCPS curricula.

DOI: Identifier not availablePMID: Identifier not available

Additional sources cited on this page

  1. Neville BW. Oral & Maxillofacial Pathology, 4e
  2. Topazian RG. Oral and Maxillofacial Infections, 4e

Browse the full evidence library →

Draft — pending faculty review. Educational use only; verify against current guidelines and primary sources before clinical application.