exclusion of spray from the other three un-anaesthetized molars, which probably will
also be very sensitive.
If the intention is to maintain the molar in the long term, then the choice of restorative
techniques expands. If the area of breakdown of the hypomineralized enamel is
relatively confined then the operator should use conventional restorative techniques. It
is however difficult to determine where the margins of a preparation should be left as
sometimes seemingly normal enamel (to visual examination) undergoes breakdown.
Amalgam is of limited use, because, further breakdown often occurs at the margins,
and it is non-adhesive so does not restore the strength of the tooth. Composite resins,
on the other hand, when used with an appropriate bonding agent in well, demarcated
lesions, should have a good success rate. Deciding where to leave the margin in these
teeth presents difficulty. Fayle (2003) described his approach of investigating
abnormal looking enamel at the margins of the defect with a slow rotating steel bur
extending into these areas until good resistance is detected. This approach is at present
not backed up by clinical studies but is a technique adopted by many dentists and
could help avoid unnecessary sacrifice of sound tissue. (See 493HFig. 9.41.)
Most hypomineralized molars with surface breakdown involving one cusp or more
will need a restoration with greater coverage. Either stainless-steel crowns or cast
adhesive copings provide the most satisfactory options.
494H
Fig. 9.39 MIH effects on the incisors; a
mild white patch on one tooth can occur
in the same mouth as more severe brown
discolouration with some surface
breakdown.495H
Fig. 9.40 MIH affecting the first
permanent molars; some breakdown of
the hypomineralised enamel is already
occurring.