title: Prevalence of infraocclusion of primary molars determined using a new 2D image analysis methodology.
abstract: The reported prevalence of infraocclusion varies widely, reflecting differences in definitions and measurement/scoring approaches. This study aimed to quantify the prevalence and extent of infraocclusion in singletons and twins during the late mixed dentition stage of dental development using a new diagnostic imaging method and objective criteria. The study also aimed to determine any associations between infraocclusion and gender, arch type, arch side and tooth type.
  
  
  
  Two samples were analysed, 1454 panoramic radiographs of singletons and 270 dental models of twins. Both samples ranged in age from 8 to 11 years. Adobe Photoshop CS5 was used to measure the extent of infraocclusion. Repeatability tests showed systematic and random errors were small.
  
  
  
  The prevalence in the maxilla was low (<1%), whereas the prevalence in the mandible was 22% in the singleton sample and 32% in the twin sample. The primary mandibular first molar was affected more often than the second molar. There was no significant difference in the expression between genders or sides.
  
  
  
  A new technique for measuring infraocclusion has been developed with high intra- and interoperator reproducibility. This method should enhance early diagnosis of tooth developmental abnormalities and treatment planning during the late mixed dentition stage of development.
authors.affiliation: School of Dentistry, The University of Adelaide, South Australia, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Odeh
authors.affiliation: School of Dentistry, The University of Adelaide, South Australia, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Mihailidis
authors.affiliation: School of Dentistry, The University of Adelaide, South Australia, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Townsend
authors.affiliation: Research Center for Oral Health Sciences, Faculty of Medicine, University of Oulu, Oulu, Finland.|Medical Research Center, Oulu University Hospital, Oulu, Finland.
authors.forename: R
authors.initials: R
authors.lastname: Lähdesmäki
authors.affiliation: School of Dentistry, The University of Adelaide, South Australia, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Hughes
authors.affiliation: School of Dentistry, The University of Adelaide, South Australia, Australia.|Institute of Dentistry, Queen Mary University of London, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Brook
mesh_terms: D000367:Age Factors; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000000981:diagnostic imaging / Q000453:epidemiology*; D008334:Mandible / Q000000981:diagnostic imaging; D008437:Maxilla / Q000000981:diagnostic imaging; D008963:Molar / Q000002:abnormalities*; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012737:Sex Factors; D014071:Tooth Abnormalities / Q000453:epidemiology*; D014094:Tooth, Deciduous / Q000002:abnormalities*
keywords: Dental models; panoramic radiographs; primary dentition; submerged teeth; tooth eruption