Pathology · patient case question
What term describes this pattern of missing teeth?
Patient case: Child with widespread absence of permanent tooth buds
Patient: Male, 8 years old
Chief Complaint: Mother: “His teeth are coming out and nothing is growing back.”
Background: Healthy, normal growth and development. No syndromic features reported. Family history not known.
Vital Signs: BP 98/62 mmHg · HR 88 bpm · T 98.4°F
Findings: Panoramic radiograph shows no developing tooth buds in the mandible apart from #17. Teeth #19 and #30 are absent. In the maxilla, several primary teeth have exfoliated and no successor buds are present except for #3 and #4, both of which have erupted. Multiple primary teeth remain with normal crown form.
Show answer and explanation
Correct answer: C. Hypodontia (oligodontia when six or more teeth are absent)
- A. Ankylosis is fusion of cementum to alveolar bone, producing an infra-occluded tooth that fails to exfoliate. It does not explain absent successors.
- B. PSEUDOANODONTIA describes teeth that are PRESENT but unerupted or impacted, so the mouth appears edentulous while the radiograph shows buds. Here the buds are genuinely absent, which is the opposite finding.
- C. CORRECT. HYPODONTIA is the congenital absence of one or more teeth, defined by the absence of the TOOTH BUD on radiographic examination. When SIX OR MORE teeth are missing excluding third molars, the term OLIGODONTIA is applied — this patient sits in that category. Extensive oligodontia should prompt evaluation for ectodermal dysplasia and for the WNT10A, PAX9, MSX1 and EDA gene pathways, and should be distinguished from acquired loss.
- D. ANODONTIA is the COMPLETE absence of teeth, meaning no tooth germs at all in either dentition. It is extremely rare and is not what this radiograph shows — several teeth are present and erupted.
Note: What this item adds is the TERMINOLOGY tier — anodontia versus hypodontia versus oligodontia versus pseudoanodontia — and the radiographic criterion, which is absence of the BUD rather than absence of the erupted tooth. Commonest congenitally missing teeth after third molars: mandibular second premolars, maxillary lateral incisors, maxillary second premolars.