Topics in Oral Medicine
Back to Abnormalities in Tooth Number

Oligodontia

From the DentTest dentistry textbook, with 10 practice questions. Last updated 6 August 2026.

Clinical case

A 10-year-old child is referred because many permanent teeth have not erupted. Clinical examination shows multiple retained primary teeth and spacing. A dental panoramic radiograph confirms absence of eight permanent tooth germs, excluding third molars. Hair, sweating and nails appear normal.

Pathophysiology

Oligodontia reflects a more extensive disturbance of tooth germ initiation than hypodontia. It may be inherited and can involve genes important in epithelial-mesenchymal interactions during odontogenesis.

Oligodontia may also be syndromic, particularly in:

The absence of multiple teeth can reduce alveolar bone development and complicate later prosthodontics rehabilitation.

Epidemiology and Risk Factors

Non-modifiable

Modifiable

Family history

Childhood cancer therapy

Syndromic disease

Craniofacial anomalies

Clinical Features

Oligodontia is defined as missing 6 or more developing teeth (excluding wisdom teeth). The congenital absence of 5 or less developing teeth is called hypodontia.

Symptoms

Signs

Missing 6 or more teeth (excluding wisdom teeth)

Retained primary teeth

Delayed eruption

Reduced alveolar ridge development

Speech concerns

Reduced lower facial height (in severe cases)

Difficulty chewing

Peg-shaped teeth (suggests ectodermal dysplasia)

Investigations

Primary investigations:

  • Full dental and medical history

  • Family history

  • Clinical examination

  • Radiographs: OPG to confirm number and distribution of missing teeth

  • Orthodontic assessment

Gold standard investigation:

Diagnosis is based on clinical examination with radiographic confirmation of 6 or more developmentally absent teeth.

This preview stops here. The full topic continues with a free account.