How to assess the prognosis of MIH in first permanent molar teeth

Assessing prognosis

When looking at first permanent molar teeth (FPM) affected with MIH we are not just assessing the immediate restorability, we are also assessing the potential for future post-eruptive breakdown.

Prognosis Categories

Good – tooth is stable and does not require long-term restorations or extractions

Moderate – MIH lesion may be restored long-term however there is some potential for future breakdown

Poor – MIH lesion is non-restorable or may be pulpally involved, with a generally poor long term prognosis (significant potential for further post-eruptive breakdown)

The prognosis of FPMs with MIH is primarily determined by

1. The position of the lesion
2. The colour of the lesion

Position of the lesion

Any MIH lesion involving cusps has an increased risk of breakdown due to occlusal trauma. Conversely lesions affecting only smooth surfaces are at lower risk of post-eruptive breakdown.

Colour of the lesion

The colour of the lesion will have a predictable affect on the potential for breakdown.

White or creamy lesions have a low potential for breakdown

Yellow lesions have a moderate potential for breakdown

Brown lesions have a high potential for breakdown

If we combine both these elements together then we start to make a realistic assessment of prognosis

Good prognosis

White or creamy lesions limited to smooth surfaces

Moderate prognosis

White or creamy lesions involving occlusal surfaces or cusps

Yellow lesions without cusp involvement

Brown lesions affecting smooth surface

Poor prognosis

Yellow lesions with cusp involvement Brown lesions affecting cusps or multi-surface