Which is the typical facies of Down syndrome?
Hypoplastic maxilla
Prognathic maxilla
Retrognathic mandible
Prognathic mandible
Skeletal findings are an underdeveloped midface, creating  a  prognathic  occlusal  relationship.  Oral  findings include  mouth  breathing,  open  bite,  appearance  of macroglossia, fissured lips and tongue, angular cheilitis, delayed eruption times, missing and malformed teeth, oligodontia, small roots, microdontia, crowding, and a low level of caries. Children with Down syndrome experience a high incidence of rapid, destructive periodontal disease, which may be related to local factors such as tooth morphology, bruxism, malocclusion, and poor oral hygiene.
Reference: McDONALD AND AVERY’S DENTISTRY for the CHILD and ADOLESCENT, 10th ed page no 527