The use of a standardised protocol, diagnostic and grading criteria will greatly enhance the quality of epidemiological studies of MIH.

This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. This study focused on the relationship between Deciduous Molar Hypomineralization (DMH) and Molar Incisor Hypomineralization (MIH). First permanent molars develop during a period similar to that of second primary molars, with possible comparable risk factors for hypomineralization. Children with DMH have a greater risk of developing MIH. Clinical photographs of clean, moist teeth were taken with an intra-oral camera in 6,161 children (49.8% girls; mean age 74.3 mos, SD ± 5.8). First permanent molars and second primary molars were scored with respect to DMH or MIH. The prevalence of DMH and MIH was 9.0% and 8.7% at child level, and 4.0% and 5.4% at tooth level. The Odds Ratio for MIH based on DMH was 4.4 (95% CI, 3.1-6.4). The relationship between the occurrence of DMH and MIH suggests a shared cause and indicates that, clinically, DMH can be used as a predictor for MIH.

With the development of the European Academy of Paediatric Dentistry (EAPD) judgment criteria, there has been increasing interest worldwide in investigation of the prevalence of demarcated opacities in tooth enamel substance, known as molar–incisor hypomineralisation (MIH). However, the lack of a standardised system for the purpose of recording MIH data in epidemiological surveys has contributed greatly to the wide variations in the reported prevalence between studies. The present publication describes the rationale, development, and content of a scoring method for MIH diagnosis in epidemiological studies as well as clinic- and hospital-based studies. The proposed grading method allows separate classification of demarcated hypomineralisation lesions and other enamel defects identical to MIH. It yields an informative description of the severity of MIH-affected teeth in terms of the stage of visible enamel destruction and the area of tooth surface affected (i.e. lesion clinical status and extent, respectively). In order to preserve the maximum amount of information from a clinical examination consistent with the need to permit direct comparisons between prevalence studies, two forms of the charting are proposed, a short form for simple screening surveys and a long form desirable for prospective, longitudinal observational research where aetiological factors in demarcated lesions are to be investigated in tandem with lesions distribution. Validation of the grading method is required, and its reliability and usefulness need to be tested in different age groups and different populations.