Failure of eruption of a lower third molar with cystic change
27-year-old male
§Chief complaint
Dull ache and swelling behind the last lower right tooth
§Medical & dental history
- 01Healthy
- 0248 never erupted
- 03Two episodes of pericoronitis in the last year
§Clinical examination
- 01Mild buccal expansion distal to 47, mucosa healthy
- 0248 not visible clinically
- 0347 vital, no mobility
- 04Mouth opening 42 mm, no trismus at time of review
§ figuresFigures (3)
Fig. 1dentigerous jaw cyst in the right mandible around and impacted wisdom tooth
“JawCyst (with arrows)” · JawCyst.jpg: Coronation Dental Specialty Group [1] derivative work: Jbarta · CC BY 3.0 · Wikimedia Commons
Fig. 2dentigerous jaw cyst in the right mandible around and impacted wisdom tooth
“JawCyst (with arrows, cropped)” · JawCyst.jpg: Coronation Dental Specialty Group [1] derivative work: Jbarta and M · CC BY 3.0 · Wikimedia Commons
Verified open-access images only, reproduced for education under their stated licences · no AI-generated or illustrative artwork · Dentigerous Cyst figures pending faculty review.
§Differential diagnosis
§Final diagnosis
Dentigerous cyst associated with impacted 48
A well-corticated unilocular pericoronal radiolucency more than 4 mm wide that attaches at the cemento-enamel junction of an unerupted tooth is the defining feature. Only histology excludes a unicystic ameloblastoma presenting identically.
§Investigations
- 01OPG — unilocular corticated pericoronal radiolucency 22 mm around crown of 48
- 02CBCT — roots of 48 in contact with the IAN canal, cortical thinning
- 03Pulp testing of 47 — vital
§Treatment plan
- 01Enucleation of the cyst with removal of 48
- 02Careful nerve-conscious technique given CBCT proximity
- 03Histopathology of the lining
§Surgical procedure
- 01Buccal envelope flap with distal relieving incision
- 02Bone removal, tooth sectioned and delivered, cyst lining enucleated intact
- 03Wound irrigated and closed primarily
§Histopathology report
Cyst wall lined by thin, non-keratinised 2-4 cell layer epithelium without rete ridge formation, mucous cell metaplasia focally, loose fibromyxoid connective tissue wall. Dentigerous cyst; no ameloblastomatous change.
§Follow-up & outcome
- 01Transient lower lip paraesthesia resolving fully by 8 weeks
- 02Radiographic bony fill at 9 months
§Clinical pearls / learning points
- 01Pericoronal space greater than 4-5 mm suggests a cyst rather than a normal follicle.
- 02Coronectomy is an alternative when the IAN is intimately related, but not when cystic change requires full enucleation and histology.
§ evidenceReferences & Evidence
Current Classification
WHO Classification of Head and Neck Tumours
5th Edition — Volume 9
WHO Classification of Tumours Editorial Board · 2022
The authoritative international classification of head and neck, odontogenic and salivary gland tumours. Current terminology on this site follows this edition.
Evidence summary
Highest level of evidence linked to this page: WHO / Official Classification.
- L1 · Classification — 3
- L4 · Research — 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
Current Classification
WHO Classification of Tumours Editorial Board. IARC / World Health Organization · 2022
The authoritative international classification of head and neck, odontogenic and salivary gland tumours. Current terminology on this site follows this edition.
Vered M, Wright JM. Head and neck pathology · 2022 · 16(1):63-75
Summary of odontogenic and maxillofacial bone tumour changes in the 5th edition WHO classification.
IARC / WHO. IARC · 2022
Continuously updated online edition of the WHO head and neck tumour classification.
Radiology References
Dunfee BL, Sakai O, Pistey R et al.. Radiographics : a review publication of the Radiological Society of North America, Inc · 2006 · 26(6):1751-68
Radiologic-pathologic correlation of benign and malignant odontogenic lesions of the jaws.
Histopathology References
Barnes L. CRC Press · 2008
Detailed histopathological reference for head and neck diagnostic criteria.
Textbook References
Neville BW, Damm DD, Allen CM et al.. Elsevier · 2024
Standard reference textbook of oral and maxillofacial pathology used throughout this atlas.
Rajendran R, Sivapathasundharam B. Elsevier · 2020
Undergraduate and postgraduate oral pathology textbook widely used in BDS and FCPS curricula.
Additional sources cited on this page
- Neville BW et al. Oral and Maxillofacial Pathology, 5th ed.
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