Molar incisor hypomineralisation
MIH affects first permanent molars and often incisors; sensitivity, breakdown and restoration difficulty are common.
Understand
MIH is a qualitative enamel defect of first permanent molars, often with affected incisors. Porous enamel may break down after eruption and cause severe sensitivity.
Assess
Examine all first permanent molars and incisors, record extent and sensitivity, and distinguish MIH from fluorosis or caries.
Apply
Prioritise prevention, desensitisation and durable coverage where needed. Restoration margins in sound enamel are more reliable; severe cases may need coordinated extraction timing advice.
Key distinctions
MIH varies from mild opacity to post-eruptive breakdown and can make brushing, anaesthesia and bonding difficult. Distinguish it from hypoplasia, fluorosis and caries by pattern and enamel character. Early identification allows desensitisation, prevention and monitoring before a first permanent molar collapses; severe cases may need orthodontic timing advice.
Think through a case
A newly erupted first permanent molar has chalky yellow enamel and sensitivity, making brushing difficult. Manage sensitivity and plaque risk while planning durable coverage.
The distinction to remember
Do not mistake a porous MIH margin for a reliable bonding substrate or assume all enamel opacity is caries.
Test your recall
Why might an MIH molar be difficult to anaesthetise or restore?
Show answer
Hypersensitivity and porous enamel complicate care.