title: Distribution and severity of molar hypomineralisation: trial of a new severity index.
abstract: BACKGROUND
  Current molar hypomineralisation (MH) indices do not guide clinicians in management of affected dentitions, and treatment is based on individual judgment.
  
  
  OBJECTIVE
  The aims of this study were to describe characteristics of MH and molar incisor hypomineralisation (MIH) and trial the new Molar Hypomineralisation Severity Index (MHSI).
  
  
  METHODS
  First permanent molars (FPMs) and permanent incisors (PIs) in 283 affected children were examined for hypomineralisation characteristics [defect colour, location, post-eruptive breakdown (PEB); restorations placed/replaced/atypical; sensitivity]. The MHSI scores were compared with treatment received (152 children).
  
  
  RESULTS
  Mean (SD) affected teeth/dentition were as follows: FPMs: 3.2 (1.0) and PIs: 1.6 (1.6). Affected FPMs showed no arch or quadrant predilection; maxillary central PIs were affected particularly. As affected FPMs/dentition increased, MIH diagnoses also increased (P = 0.009). Among FPMs, defects most prevalent were brown (47%) and cuspal (74%); 67% showed PEB. Before study entry, 43% of FPMs had restorations placed/replaced. Among PIs, white defects were common (65%) on smooth surfaces; sensitivity was rare. Affected FPMs received more restorations and extractions than unaffected FPMs (P = 0.0001). As MHSI scores increased, FPM treatments/dentition increased (number, invasiveness). All characteristics were significant in predicting treatment (logistic regression model).
  
  
  CONCLUSIONS
  A spectrum from MH to MIH occurred. The MHSI characteristics were predictive of the treatment of affected FPMs and can guide management.
authors.affiliation: Paediatric Dentistry, Melbourne Dental School, The University of Melbourne, Melbourne, Vic., Australia.
authors.forename: Kelly
authors.initials: K
authors.lastname: Oliver
authors.forename: Louise B
authors.initials: LB
authors.lastname: Messer
authors.forename: David J
authors.initials: DJ
authors.lastname: Manton
authors.forename: Karen
authors.initials: K
authors.lastname: Kan
authors.forename: Fiona
authors.initials: F
authors.lastname: Ng
authors.forename: Christopher
authors.initials: C
authors.lastname: Olsen
authors.forename: John
authors.initials: J
authors.lastname: Sheahan
authors.forename: Margarita
authors.initials: M
authors.lastname: Silva
authors.forename: Narisha
authors.initials: N
authors.lastname: Chawla
mesh_terms: D003744:Dental Enamel Hypoplasia / Q000628:therapy*; D006801:Humans; D012720:Severity of Illness Index