What it is
Molar-Incisor Hypomineralisation (MIH) is a developmental condition in which the enamel of one or more permanent first molars is weaker and less mineralised than normal. The permanent incisors may also be affected.
The enamel can appear:
- White, cream, yellow or brown
- Patchy or irregular
- More porous and fragile than normal enamel
Affected teeth may be sensitive, particularly to cold, brushing or dental treatment, and the weakened enamel can break down after the tooth erupts.
Signs of MIH
Common signs include:
- Clearly defined white, yellow or brown areas on permanent molars or incisors
- Sensitivity to cold, sweet foods or brushing
- Difficulty keeping affected teeth clean
- Enamel breaking down soon after eruption
- Cavities developing rapidly in affected areas
- Children avoiding brushing because their teeth are sensitive
- Difficulty achieving comfortable dental treatment because of sensitivity
Why It Happens
The exact cause of MIH is not fully understood. It occurs while the permanent teeth are developing before they erupt into the mouth.
MIH is *not caused by poor brushing or eating too much sugar*. However, affected enamel is more vulnerable to plaque, decay and breakdown once the tooth has erupted.
How It’s Managed
Treatment depends on the child’s age, symptoms and severity of the enamel defect.
Management may include:
- Fluoride varnish and other remineralisation treatments
- Desensitising products
- Fissure sealants to protect vulnerable grooves
- Glass ionomer or composite restorations
- Stainless steel crowns for severely affected molars
- Careful monitoring of erupting permanent teeth
- Preventive advice and regular dental visits
- Referral for orthodontic or restorative planning when teeth have a poor long-term prognosis
Why Early Treatment Matters
MIH can become more difficult to manage once the fragile enamel starts breaking down.
Early assessment allows us to:
- Identify affected teeth as they erupt
- Control sensitivity
- Protect weak enamel before it breaks down
- Prevent or reduce decay
- Make brushing more comfortable
- Plan treatment before extensive damage occurs
- Help children become comfortable with dental care
When It’s Treated:
Children with MIH benefit from assessment as soon as affected permanent teeth begin to erupt.
Treatment is particularly important when:
- A tooth is sensitive
- Enamel is breaking down
- There are early signs of decay
- A child is struggling to brush affected teeth
- A molar is difficult to restore because of extensive enamel defects
- The child is becoming fearful of dental treatment because of sensitivity or previous painful experiences
