What is Molar Hypomin?
"Molar Hypomin" is short for "Molar Hypomineralisation" (the technical term for Chalky Molars), a very troublesome D3 that causes lots of suffering and costs around the world. On the bright side however there is good reason to expect this widespread problem may eventually go away (i.e. become preventable), once scientists figure out what causes it – and that’s an exciting quest many families are helping us with.
What does the name mean?
As the name implies, a key feature of Molar Hypomin is that it’s quite selective for certain teeth. Molars of course are back teeth and those most prone to this type of D3 are the "6-year molars" – otherwise known as the first "adult" or "permanent" molars whose eruption into the mouth typically occurs at 6–7 years of age. Other molars can also be affected including the "2-year molars" in toddlers and the "12-year molars". Sometimes in badly affected children their front teeth (incisors) can have this problem too, in which case you may hear the term "Molar-Incisor Hypomin" or its abbreviation "MIH" used. "Hypomineralisation" is just a technical way of saying "abnormally low amounts of calcium mineral" – in other words, "Hypomin" describes tooth enamel that is often soft and porous (chalky) rather than hard and shiny white. And it’s that chalkiness which can cause problems, as we explain below.
What does it look like?
Molar Hypomin enamel is easy to recognise when it also affects the front teeth – as seen in this bad case in a 10-year-old (top picture), the enamel appears more opaque than normal and its colour may range from unnaturally "extra white" through creamy yellow to brown. The defective patches usually have quite obvious boundaries with normal enamel which is why dental people refer to them as "demarcated opacities". In contrast, opacities associated with excessive fluoride have a more diffuse appearance (i.e. dental fluorosis). This picture also shows how the problem affects some teeth but not others – whereas the two middle front teeth (central incisors) are really wonky, the next teeth outside them (lateral incisors) are both fine.
You can tell a lot about how bad the Molar Hypomin is just from its appearance. In mildly affected teeth, the defective enamel is usually "extra white" and the tooth surface is hard and intact (although perhaps a little duller than normal), as can be seen in the middle picture – those back teeth are the 1-year and 2-year molars in a 4-year-old. In moderate cases, the enamel has more colour than normal (typically creamy-yellow) and the surface might have started to crumble (i.e. suffer "breakdown") as seen above in the right front tooth. In severe cases, such as the badly affected 6-year molar (lower picture), the defective enamel is a creamy brown colour and so soft that a large "pothole" has formed even before the tooth has finished erupting. Note that often these potholes start out being simply the result of Molar Hypomin and have nothing to do with decay (i.e. "cavities" or dental caries), as explained further below.
Dentists will grade the severity of your child's Molar Hypomin taking into account not only how badly each tooth is affected (i.e. colour, hardness and size of defective patch, plus any pothole development) but also the number of teeth affected. The number of defective teeth can vary widely, from one to six or more. In mild cases, typically just one or two molars are defective whereas all four of the 6-year molars plus some incisors, and other teeth too, might be affected in particularly bad cases of Molar Hypomin. And what became of those chalky front teeth in our 10-year-old? We're pleased to say there was a happy ending! (click here to see the result)
What's the problem with it?
Unsurprisingly the chalky enamel in Molar Hypomin can lead to several problems – the three main issues for sufferers are sensitivity (dental pain or toothache), crumbling and potholes leading to increased risk of decay (dental caries), and unsightly appearance in the case of front teeth. Dentists can also strike problems when trying to fix these defective teeth. So, although Molar Hypomin kids can be perfectly healthy in all other regards, it's possible their dental condition can be quite troublesome if not cared for well.
In Molar Hypomin the dental pain (sore tooth or jaw) might be triggered by hot or cold foods or toothbrushing, and vary in severity from a minor inconvenience to full-on disruption of daily life. It is important to realise that Molar Hypomin teeth can be painful even if they show no evidence of potholes, cavities or dental caries. In other words, even children who have taken great care to keep their mouths free of decay (and fillings) can unfortunately end up with bad toothache as a consequence of Molar Hypomin. Not knowing this, some parents in the past have felt (quite inappropriately) that they were to blame for the "neglected" condition of these "rotten teeth". A good rule of thumb is, if the rest of the teeth are free of decay and it’s only the 6-year molars that are painful or crumbling, then there's a better than average chance that Molar Hypomin may be to blame.
Putting pain issues aside however, those kids affected more severely by Molar Hypomin do have a higher risk of getting caries (cavities) for several reasons. First, when their enamel is chalky and porous rather than shiny hard, the "plaque bugs" (bacteria) that cause dental caries can penetrate the tooth more easily and so become inaccessible to cleansing with a toothbrush. This situation only gets worse when the enamel is soft and crumbly, giving even more places for bacteria to hide. Third, the extreme sensitivity of some Hypomin teeth can stop kids brushing in that part of the mouth, so aggravating the risk for caries – a dental example of a vicious circle.
Unsightly front teeth may not only lead to anxiety for the owner but also create awkwardness for onlookers. Fortunately, Dentists these days have many options for improving the cosmetic appearance of front teeth, and often these work well when the defective patches are relatively small. In badly affected molars however, the defective enamel can cause Dentists all manner of problems and as a result some types of fillings don't last as long as normal. Another problem is that sensitive Molar Hypomin teeth can be slow to go numb with local anaesthetic, which of course is awkward for both Dentist and child. For these reasons, your Dentist might suggest using an alternative type of anaesthetic or refer you to a specialist (read more).