title: Objective growth monitoring of the maxilla in full term infants.
abstract: OBJECTIVE
  To develop a non-invasive method for longitudinal maxillary volume measurements and to provide first normative data.
  
  
  METHODS
  Thirty-four healthy infants served as a gold standard for a growing population sample. Alginate impressions were taken of the upper jaw within the first week after birth, and consecutively at different stages of development. The plaster casts were digitised by an optical scanner generating a high resolution polygon mesh of each object. The digital models were aligned to a reference coordinate system with an iterative, landmark-independent procedure. Biometric linear and volume measurements were obtained by using feature-dependent calculations independent of landmark placements. Intra-investigator reproducibility was tested by repeated alignments and measurements of 30 randomly selected casts. To assess the effect of mesh resolution, the reproducibility test was repeated with low resolution models. The method was proved to be valid on the defined gold standard consisting of 96 consecutive edentulous casts.
  
  
  RESULTS
  Feature-dependent, linear distances are less error prone (0.56-2.66%) compared to subjectively determined measurements (0.88-3.65%). The same applies to feature-dependent volume calculations (4.34%) compared to subjectively determined volumes (4.95%). Mesh resolution shows an effect (p<or=0.001) only on two linear measurements: palatal depth and palatal length. Growth of the individuals in the population sample was evidently confirmed by the maxillary volume measurements (asymptotic pattern) and by comparisons of head circumference (proportional pattern).
  
  
  CONCLUSIONS
  The described method is non-invasive, precise and without any risk for the infant. Maxillary volume calculation could serve as an important biometric measurement for bone growth evaluation.
authors.affiliation: Poliklinik für Kieferorthopädie, Westfälische Wilhelms-Universität Münster, Waldeyer Str. 30, 48129 Münster, Germany. hohoffa@uni-muenster.de
authors.forename: Ariane
authors.initials: A
authors.lastname: Hohoff
authors.forename: Thomas
authors.initials: T
authors.lastname: Stamm
authors.forename: Ulrich
authors.initials: U
authors.lastname: Meyer
authors.forename: Dirk
authors.initials: D
authors.lastname: Wiechmann
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ehmer
mesh_terms: D001699:Biometry / Q000379:methods; D002508:Cephalometry / Q000379:methods; D002657:Child Development / Q000502:physiology; D005260:Female; D006257:Head / Q000033:anatomy & histology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008437:Maxilla / Q000033:anatomy & histology / Q000254:growth & development*; D008953:Models, Anatomic; D010159:Palate / Q000033:anatomy & histology; D015203:Reproducibility of Results; D012307:Risk Factors; D047929:Term Birth