cause problems.
Molar-incisor hypomineralization has been defined as 'hypomineralization of
systemic origin of one to four permanent molars frequently associated with affected
incisors'. The expression of the phenomenon can vary in severity between patients but
also within a mouth, so in one quadrant there may only be a small hypomineralized
area, while in others almost total destruction of the occlusal surface.(See 489HFigs. 9.39
and 490H9.40.)
Usually the incisors do not suffer the same breakdown of the surface and sensitivity as
the molars. However, they do frequently cause a cosmetic defect. This can be treated
as the child becomes conscious of it, either by coverage with composite (veneer) or
partial removal of the defect and coverage with composite (localized composite
restoration). Details of these treatment techniques will be covered in 491HChapter 10.
The first problem to remedy in molars is the sensitivity. Various desensitizing agents
theoretically and anecdotally do help, but no clinical trials specifically related to MIH
have been reported. They include:
- Repeated application of 5% sodium fluoride varnish (Duraphat).
- Commercially available 'sensitive tooth toothpastes'.
- Daily use of 0.4% stannous fluoride gels.
Fissure sealants can be useful where the affected areas are small and the enamel is
intact. The use of bonding agents as described above under the resin sealant should
help with bonding if the margin of the sealant is left on an area of hypomineralized
enamel. The application of the bonding agents alone, once polymerized may reduce
the sensitivity in the affected teeth per se. It is important to remember to monitor
fissure sealants in these teeth very carefully as there is a high chance of marginal
breakdown. If there is surface breakdown the tooth will require some form of
restoration. The first decision to make is whether the clinician needs to maintain the
tooth throughout life or if it is more pragmatic to consider extraction (492HChapter 14). If
the decision is that the first molars will be extracted as part of a long-term orthodontic
plan, it is probable that they will still need temporisation because of the high level of
sensitivity. These teeth are very difficult to anaesthetize, often staying sensitive when
the operator has given normal levels of analgesic agent. If a child complains during
treatment of a hypomineralized molar tooth, credibility should be given to their
grievance. If a child experiences pain or discomfort during treatment, they will
become increasingly anxious in successive treatments. This has been shown to be true
for 9-year-old children, where dental fear, anxiety, and behaviour management were
far more common in those children with severely hypomineralized first permanent
molars when compared with unaffected controls.
Inevitably, a balance has to be made between using simpler methods, such as dressing
with a glass ionomer cement that may well need replenishment often on several
occasions before the optimum time for extraction, and deciding early within the
treatment to provide a full coverage restoration, for example. a stainless-steel crown
which should last without requiring replacement prior to extraction time. All adjuncts
to help the analgesia, such as inhalation sedation should be used, if indicated. It is also
useful to use rubber dam for all the usual reasons plus the protection afforded by