title: Molar incisor hypomineralisation: prevalence in Jordanian children and clinical characteristics.
abstract: OBJECTIVE
  To investigate Molar Incisor Hypomineralisation (MIH) in Jordanian children in terms of prevalence, distribution and severity of defects.
  
  
  METHODS
  A crosssectional national study with a representative sample was used. A multistage random sampling system yielded 3,666, 7-9 year-old schoolchildren, from 97 public, private and UNRWA schools from Amman, Irbid and Al-Karak. A questionnaire of six sections was sent to the parents with a consent form to participate in the study. A total of 3,241 children participated resulting in a response rate of 88.4%. A single calibrated investigator examined all children using established criteria for MIH and molar hypomineralisation (MH). Analysis of data was performed with a p value set at 0.05.
  
  
  RESULTS
  Of the children examined, 570 (17.6%) were diagnosed with MIH with more females affected than males (53% vs. 47%). The 570 subjects were distributed as MIH cases in 196 children (34.4%) and MH cases in 374 children (65.6%) given that at least one incisor was erupted. Mandibular molars and maxillary central incisors were more frequently affected (p<0.05). No significant difference was found between right and left sides of the mouth. Most defects were mild in severity (44%) and severity increased with age and was related to the number of teeth affected (p<0.05). MIH teeth were more severely affected than MH teeth.
  
  
  CONCLUSIONS
  MIH was common among 7-9 year-old Jordanian children with a prevalence of 17.6% and was gender related. MH was more common than MIH and can be considered a mild form of an MIH spectrum. Majority of MIH and MH cases were mild in nature but demonstrated an agerelated severity.
authors.affiliation: Dr. F.I. Zawadieh. P.O.Box 488, Irbid 211-10 Jordan. fedazawaideh@just.edu.jo
authors.forename: F I
authors.initials: FI
authors.lastname: Zawaideh
authors.forename: S H
authors.initials: SH
authors.lastname: Al-Jundi
authors.forename: M H
authors.initials: MH
authors.lastname: Al-Jaljoli
mesh_terms: D000367:Age Factors; D018912:Arabs; D002648:Child; D003430:Cross-Sectional Studies; D003744:Dental Enamel Hypoplasia / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology; D007597:Jordan / Q000453:epidemiology; D008297:Male; D008963:Molar / Q000473:pathology; D015995:Prevalence; D012744:Sex Ratio