Aim: This was to examine the records of 182 children (aged 6-14 years) with molar-incisor-hypomineralisation (MIH) or molar hypomineralisation (MH) in order to develop and examine a Hypomineralisation Severity Index for first permanent molars (FPMs).
Study design: Records of 429 FPMs in these children were examined and scored for eruption status, extent of hypomineralisation, sensitivity, number of restorative treatments; summed scores were converted to an index for each dentition (possible range: 1.25-7.00). Indices were examined regarding medical conditions occurring singly or in combinations in parentally-recalled children's histories to age 3 years; mean indices were compared for dentitions with these conditions/combinations.
Results: The proportion of FPMs receiving no/preventive treatment was higher in dentitions with MH than with MIH (56% vs. 41%); restorative treatment for FPMs was more frequent in dentitions with MIH than with MH (45% vs. 29%). Dentitions with MIH had higher severity indices than those with MH (MIH: index range: 3.25-5.25: 43%; MIH: index range: 1.25-2.00: 61%). Mean severity indices clearly had a higher trend in dentitions of children with certain condition combinations than for those without. Ten condition combinations each contained 3 to 5 medical conditions; 11/12 condition combinations included fevers; 9/12 included chicken pox; 9/12 included perinatal conditions, 6/12 included antibiotic use.
Conclusions: A preliminary Hypomineralisation Severity Index developed for dentitions with hypomineralised first permanent molars in children has shown that MIH and MH form part of an MIH spectrum, where MIH is a more severe form of the condition than MH. The index has indicated associations between hypomineralisation of these molars and combinations of medical conditions, particularly implicating fevers, chicken pox, perinatal conditions and antibiotic use. Further clinical studies are indicated to validate the proposed index and confirm its prognostic value in treatment planning.