title: Evaluation of a 3D stereophotogrammetric technique to measure the stone casts of patients with unilateral cleft lip and palate.
abstract: OBJECTIVE
  To assess a three-dimensional stereophotogrammetric method for palatal cast digitization of children with unilateral cleft lip and palate.
  
  
  METHODS
  As part of a collaboration between the University of Milan (Italy) and the University CES of Medellin (Colombia), 96 palatal cast models obtained from neonatal patients with unilateral cleft lip and palate were obtained and digitized using a three-dimensional stereophotogrammetric imaging system.
  
  
  METHODS
  Three-dimensional measurements (cleft width, depth, length) were made separately for the longer and shorter cleft segments on the digital dental cast surface between landmarks, previously marked. Seven linear measurements were computed. Systematic and random errors between operators' tracings, and accuracy on geometric objects of known size were calculated. In addition, mean measurements from three-dimensional stereophotographs were compared statistically with those from direct anthropometry.
  
  
  RESULTS
  The three-dimensional method presented good accuracy error (<0.9%) on measuring geometric objects. No systematic errors between operators' measurements were found (p > .05). Statistically significant differences (p < 5%) were noted for different methods (caliper versus stereophotogrammetry) for almost all distances analyzed, with mean absolute difference values ranging between 0.22 and 3.41 mm. Therefore, rates for the technical error of measurement and relative error magnitude were scored as moderate for Ag-Am and poor for Ag-Pg and Am-Pm distances. Generally, caliper values were larger than three-dimensional stereophotogrammetric values.
  
  
  CONCLUSIONS
  Three-dimensional stereophotogrammetric systems have some advantages over direct anthropometry, and therefore the method could be sufficiently precise and accurate on palatal cast digitization with unilateral cleft lip and palate. This would be useful for clinical analyses in maxillofacial, plastic, and aesthetic surgery.
authors.affiliation: Dipartimento di Morfologia Umana e Scienze Biomediche Città Studi, via Mangiagalli 31, I-20133 Milano, Italy. chiarella.sforza@unimi.it
authors.forename: Chiarella
authors.initials: C
authors.lastname: Sforza
authors.forename: Marcio
authors.initials: M
authors.lastname: De Menezes
authors.forename: Elena
authors.initials: E
authors.lastname: Bresciani
authors.forename: Ana M
authors.initials: AM
authors.lastname: Cerón-Zapata
authors.forename: Ana M
authors.initials: AM
authors.lastname: López-Palacio
authors.forename: Myriam J
authors.initials: MJ
authors.lastname: Rodriguez-Ardila
authors.forename: Lina M
authors.initials: LM
authors.lastname: Berrio-Gutiérrez
mesh_terms: D002648:Child; D002971:Cleft Lip / Q000473:pathology*; D002972:Cleft Palate / Q000473:pathology*; D003105:Colombia; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007558:Italy; D008297:Male; D003765:Models, Dental; D010780:Photogrammetry / Q000379:methods*