Midline spaces.
D000293:Adolescent; D000717:Anatomy, Comparative; D000818:Animals; D002648:Child; D003817:Dentition; D003970:Diastema; D007312:Eulipotyphla; D006801:Humans; D007742:Labial Frenum / Q000002:abnormalities* / Q000601:surgery; D008310:Malocclusion / Q000453:epidemiology* / Q000209:etiology; D008437:Maxilla / Q000196:embryology; D009971:Orthodontics, Corrective