AtlasDevelopmentalAmelogenesis Imperfecta

Developmental Disorders

Amelogenesis Imperfecta

aka AI · Hereditary Enamel Defects

Group of inherited disorders affecting enamel formation resulting in hypoplastic, hypomature, or hypocalcified enamel.

Gene examples
AMELX, ENAM, MMP20, KLK4
Classification
Witkop (Types I-IV)
Treatment
Crowns, veneers, implants

§ figuresFigures (3)

Fig. 1amelogenesis imperfecta, hypoplastic type. Note the association of pitted enamel and open bite.

“B amelogenesis imperfecta” · see above · CC BY 2.0 · Wikimedia Commons

Fig. 2amelogenesis imperfecta, hypomineralised type. The enamel is rough, soft and discoloured.

“E amelogenesis imperfecta” · see above · CC BY 2.0 · Wikimedia Commons

Fig. 3Amelogenesis imperfecta, hypomineralised type. The enamel is rough, soft and discoloured. In this case it's part of cone rod dystrophy syndrome. Various enamel defects (both hypoplastic and hypomineralised) coexist in th

“F amelogenesis imperfecta” · see above · CC BY 2.0 · Wikimedia Commons

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

§ overviewOverview

Genetically heterogeneous conditions with enamel abnormalities without systemic disease.

§ icdICD Classification

K00.5

§ etiologyEtiology

  • 01Mutations in AMELX, ENAM, MMP20, KLK4, FAM83H genes
  • 02Autosomal dominant, AR, or X-linked inheritance

§ epidemiologyEpidemiology

Prevalence 1:700 to 1:14,000 depending on population.

§ pathogenesisPathogenesis

Defective amelogenin secretion (hypoplastic), impaired enamel matrix removal (hypomature), or deficient mineralisation (hypocalcified).

§ clinicalClinical Features

  • 01Thin, pitted or absent enamel (hypoplastic type)
  • 02Soft, cheese-like enamel (hypocalcified)
  • 03Opaque, mottled enamel (hypomature)
  • 04Anterior open bite common
  • 05Tooth sensitivity

§ differentialDifferential Diagnosis

  • 01Fluorosis
  • 02Dentinogenesis imperfecta
  • 03Molar-incisor hypomineralisation
  • 04Chronological hypoplasia

§ histopathHistopathology

  • 01Reduced enamel thickness or prismatic disruption
  • 02Dentin normal

§ radiographicRadiographic Features

  • 01Thin or absent enamel with normal dentin contrast (hypoplastic)
  • 02Enamel and dentin similar radiodensity (hypocalcified)

§ investigationsInvestigations

  • 01Clinical + family history
  • 02Genetic testing for confirmation

§ classificationClassification

  • 01Type I — Hypoplastic (14 subtypes)
  • 02Type II — Hypomature (6 subtypes)
  • 03Type III — Hypocalcified (4 subtypes)
  • 04Type IV — Hypomature-hypoplastic with taurodontism

§ treatmentTreatment

  • 01Preventive fluoride varnish
  • 02Composite restorations / veneers
  • 03Full-coverage crowns for severe cases
  • 04Overdentures or implants long-term

§ complicationsComplications

  • 01Rapid attrition
  • 02Caries susceptibility
  • 03Aesthetic and psychosocial impact

§ prognosisPrognosis

Good with early restorative intervention; lifelong dental maintenance required.

§ examKey Examination Points

  • 01Classify by Witkop classification
  • 02Distinguish from DI by dentin appearance
  • 03X-linked forms affect males more severely

§ revisionQuick Revision Summary

  • 01AI = enamel only, DI = dentin only
  • 02Type III hypocalcified = soft, rapidly lost enamel
  • 03AMELX mutation = X-linked hypoplastic

§ vivaBDS Viva Questions

  • 01What genes are implicated in AI?
  • 02How do you differentiate AI from fluorosis?
  • 03Describe the Witkop classification.

§ mcqsMCQs — Assessment (3)

Question 1

Which type of AI results in enamel that chips away easily after eruption?

Question 2

AMELX mutation causes which inheritance pattern?

Question 3

Which condition affects ONLY dentin?

§ 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. Witkop CJ. Am J Med Genet 1988;28:345
  2. Neville BW. Oral & Maxillofacial Pathology, 4e

Browse the full evidence library →

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