Solitary median maxillary central incisor (SMMCI) is a rare dental anomaly. It is usually considered as a minor manifestation (variant) of holoprosencephaly (HPE).
It is estimated to occur in 1:50,000 live births.
It is a complex disorder consisting of multiple, mainly midline defects of development resulting from unknown factor(s) operating in utero about the 35-38th day from conception. The aetiology is uncertain.
A missense mutation in the SHH gene (I111F) at 7q36 may be associated with SMMCI 2.
Up to 90% have choanal atresia,midnasal stenosis or pyriform aperture stenosis
- single,midline central maxillary incisor
- midpalatal vomerine ridge
- v-shaped palate
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