title: Comparative morphology of normal and cleft minipigs demonstrates dual origin of incisors.
abstract: OBJECTIVE
  The incisors of the mammalian dental arch develop from tissues arising from separated facial prominences. These primordial craniofacial structures undergo complex morphogenetic processes as they merge and fuse in a time and space dependent fashion. However, local contributions of precursor facial prominences to the incisors that develop subsequently remain unknown. The purpose of this study was to characterize the development of all three deciduous upper rostral teeth in the pig (Sus scrofa f. domestica) for the identification of the likely facial prominence contributions to the incisors based on normal and pathological developmental relationships.
  
  
  METHODS
  Embryonic minipigs were collected between gestational days 20-36 (E20-36), processed for histological analysis and subjected to computerized 3D modelling. The location and morphology of the incisors (i) in these specimens were characterized and compared between developmental stages. A second set of neonatal minipigs displaying cleft lip and/or cleft palate defects were also obtained and incisor locations and eruption patterns were morphologically examined.
  
  
  RESULTS
  Palate formation begins during the third week of gestation (E20) in the minipig with ossification of the premaxilla initiating soon afterwards (E24). The third incisor (i3) develops caudally to the contact seam formed by the fusion of the primary and secondary palates in normal embryos. All cleft animals displayed normal i3 and canine, on other hand, development of i1 and i2 was often disrupted similar to human.
  
  
  CONCLUSIONS
  Our observations suggest a dual embryonic origin of the incisors in minipigs with the first and second incisors originating from the frontonasal prominence whilst the third incisor forms from tissues derived from the maxillary prominence.
authors.affiliation: Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic.
authors.forename: Iveta
authors.initials: I
authors.lastname: Putnová
authors.forename: Svetlana
authors.initials: S
authors.lastname: Odehnalová
authors.forename: Vítězslav
authors.initials: V
authors.lastname: Horák
authors.forename: Ladislav
authors.initials: L
authors.lastname: Stehlík
authors.forename: Ivan
authors.initials: I
authors.lastname: Míšek
authors.forename: Scott
authors.initials: S
authors.lastname: Lozanoff
authors.forename: Marcela
authors.initials: M
authors.lastname: Buchtová
mesh_terms: D000818:Animals; D002971:Cleft Lip / Q000196:embryology*; D002972:Cleft Palate / Q000196:embryology*; D021621:Imaging, Three-Dimensional; D007180:Incisor / Q000196:embryology*; D009805:Odontogenesis / Q000502:physiology*; D013552:Swine; D013556:Swine, Miniature