Clinical Cases Ortho/paeds book

Question 1

Causes of unerupted or missing upper permanent central incisor

Answer 1

Missing
• Congenitallyabsent.
• Avulsed.
• Extracted.

Present but unerupted
• ectopic position of the tooth germ.
• Dilaceration and/or displacement due to trauma.
• Scar tissue.
• Supernumerarytooth.
• Crowding.
• Pathology, e.g. cyst, odontogenic tumour.

Question 2

Classification of supernumerary teeth

Answer 2

1. Conical or peg-shaped – most often lies between upper centrals, and may produce no effect, a median diastema, incisor rotation or failure of upper 1 eruption, 75–78%o s/n.
2. Tuberculate or barrel-shaped– most usually associated with unerupted lower 1 ;~12% o s/n.
3. Supplemental
   resembles and lies adjacent to the last tooth of a series (2’s,5’s, 8’s); likely to produce crowding, centreline shi t (Fig. 2.3B).
4. Odontome– maybe either compound or complex; compound is more common in the anterior maxilla; complex is more common in the premolar and molar areas; associated with unerupted/displaced teeth.