Prevalence of molar-incisor-hypomineralisation among 8-year-olds








If at least two first permanent molars are affected at 8 years of age, then there is an increased risk teeth erupting later being affected 












The average estimated prevalence of MIH was 8.3%.»


Dentists often see patients with developmental defects in tooth enamel. The characteristically white, brown or yellow stains are present from when the tooth first erupts. But, how common are these defects?

A recent study by NIOM and several collaborators looked at the frequency of patients with teeth affected by molar-incisor-hypomineralisation (MIH). In addition it sought to discover whether the number of affected teeth in the early developing dentition, could predict whether the later erupting teeth will be affected.

The study

The study was retrospective, with both cross-sectional and longitudinal components. It was based on electronic oral health records of all 8-year-olds examined between 2002 and 2016 by the public oral health services in Helsinki.

The findings

The average estimated prevalence of MIH was 8.3%. This is comparable to that previously reported in the literature.It was revealed that the upper first permanent molar were most commonly affected.

In the follow-up part of the study, it was observed that those who had at least two affected first permanent molars at 8 years of age, had an increased risk of teeth erupting later being affected, compared to those with only one tooth affected.

Collaborative partners

This study was a collaboration between the University of Helsinki, Helsinki University Hospital, Department of Social Services and Health Care, City of Helsinki, Ministry of Social Affairs and Health, Helsinki, Finland and NIOM.

Pictured: The characteristically white, brown or yellow stains are present from when the tooth first erupts. Credit: Aida Mulic.


Battsetseg Tseveenjav, Jussi Furuholm, Aida Mulic, Håkon Valen, Tuomo Maisala, Seppo Turunen, Sinikka Varsio, Merja Auero & Leo Tjäderhane (2020): Estimating molarincisor-hypomineralization among 8-year-olds based on 15-year public oral health practice-based data, Acta Odontologica Scandinavica, DOI: 10.1080/00016357.2020.1751274

NIOM Newsletter May 2020