Molar Incisor Hypomineralisation

Molar Incisor Hypomineralisation (MIH) is a condition affecting the enamel of permanent teeth. Most commonly the first permanent molars and incisors are affected.
Normally, the enamel is white and very hard but in cases of MIH the enamel can be creamy or have a yellow/brown colour. The texture is often rough and tends to chip away very easily.
These teeth are often sensitive to cold and the child may be reluctant to brush them. They are also at a higher risk of developing dental caries (decay).

MIH has been described as a global dental problem. The prevalence varies considerably from a few percent in a study from China to almost 40% in Demark and Brazil. A study undertaken in Perth in 2008 stated a prevalence of 22%.

Various causes of MIH have been mentioned but the aetiology still remains unclear. Some of the possible causes are:

  • Environmental conditions
  • Respiratory tract infections
  • Perinatal complications
  • Dioxins
  • Oxygen starvation and low birth weight
  • Calcium and phosphate metabolic disorders
  • Childhood diseases
  • Antibiotics
  • Prolonged breast-feeding

Treatment often starts with desensitizing toothpastes or gels and temporary coatings until a definitive treatment plan can be formulated. This treatment may be delayed to allow all the first permanent molars to fully erupt.
At this early stage it may be appropriate for the patient to be reviewed by an orthodontist to assess the growth and development. Once this is completed a treatment plan can be presented.

Treatment of minor cases of MIH may only require the teeth to be restored (filled) with a composite resin (tooth coloured) restoration. In moderate to severe cases preformed stainless steel crowns are often placed. In some cases with severe MIH the first permanent molars may be extracted to allow other molars to erupt into their position.

If the front teeth are affected they may require some cosmetic improvements. This may involve external bleaching followed by masking the defect with a tooth coloured filling material. This treatment is often delayed until growth completion unless there are specific aesthetic concerns expressed by the patient or parents.

Treatment is often carried out in the clinic with local anaesthetic. In cases where the child is anxious or the teeth are very sensitive, relative analgesia (sedation) can be used. Where there is extensive treatment to be performed arrangements can be made for this to be completed under a general anaesthetic.