Molar-Incisor Hypomineralisation: defects 1st permanent molars w defects permanent incisors (unknown aetiology), “hypomin (of systemic origin) of 1-4 permanent 1st molars & w affected incisors”, opaque discolourations to soft & fragile yellow or brown defects, severe cases enamel disintegrates under occlusal loads, “post-eruptive breakdown”, referrals from SDS, difficult to deal w, restore 1st molars (maintained indefinitely), extract & let 2nd molars take place (<8 or 9, sure 7s aren’t hypoplastic, big teeth little mouths)