HYPOPLASTIC AND HYPOMINERALISED TEETH
The term “hypoplastic” means less quantity of enamel, and the term “hypomineralised”
means less mineralised tissue. Basically this involves a tooth which is less mineralised
therefore more porous. A hypoplastic tooth has reduced amount of enamel so the surface
may be rough. Your child may have teeth which have developed in this manner. The most
common teeth to be affected are the second primary molars which erupt at the age of 2 ½
years or in the permanent dentition the first permanent molars which erupt at age 6.
Hypoplastic and hypomineralised teeth develop as a result of an event which has occurred
during the development of the enamel. There have been over 100+ different sources
identified in causing hypoplastic and hypocalcified teeth. Some of these causes include
infections (tonsillitis, chest infections, ear infections, acute gastrointestinal infections etc),
fevers, convulsions, nutritional imbalances, electrolyte imbalances, measles, chicken pox,
hand, foot and mouth diseases, other viral infections, etc, etc.
In some children when these infections or causes occur, the cells which lay down the enamel
start to lay down enamel which is less mineralised and more porous therefore giving the
appearance of mottled, yellow or white opacities, or the enamel is laid down in very thin
sheets. These areas are more prone to breaking and wearing down and rough surfaces will
attract plaque and food retention. Ultimately these teeth can become prone to developing
decay.
The severity of hypoplasia and hypocalcified teeth varies where some children will have very
slight yellow/white flecks and no discomfort, ranging right through to where the entire tooth
surface may be affected and the child experiences sensitivity to air and cold substances.
The management of these teeth depends on the severity. Each child is different and in mild
cases fissure sealants to protect the surfaces on top of the teeth can be applied or
restorations. Where over 50% of the surface is involved a crown (stainless steel) may be
required to protect the surface until the child is old enough to have a permanent gold or
ceramic crown.
In more severe cases a consultation with an orthodontist may be required and a decision to
extract the severely affected teeth may be taken. This would allow the developing second
permanent molars to take their place. An OPG radiograph is taken by the orthodontist which
will show all the new developing permanent teeth and their position. The reason for taking
out these severely affected teeth in children is to avoid them from having repetitive dental
care (restorations, root canals, crowns) over time on these same weak teeth. If these weak
teeth are extracted while the children are growing there is a good chance that the second
permanent molars which are developing in the bone behind these affected teeth will drift
forward and erupt into their spaces.
Figures 1 and 2 show hypomineralised permanent molar teeth for a seven year old girl. The
teeth have a yellow colour in comparison to her remaining teeth which have white enamel.
When “drilling” into this affected enamel it is similar to drilling into cheese. This
hypomineralised enamel is very porous and fissure sealants and fillings do not bond well to
it. She experienced multiple restorations from her dental therapist and dentist, which
continued to break and fail. An OPG radiograph showed the presence of permanent second
molars developing in the bone, so it was decided to extract the affected teeth under a short
general anaesthetic and allow the second permanent molars to drift forward.
Figures 3 and 4 show hypoplastic second primary molars in a 4 year old boy. The surface is
rough, allowing plaque and food to trap readily onto this surface leading to decay. Stainless
steel crowns were placed on these teeth.
Figure 1.
Figure 2.
Hypocalcified
upper first
permanent
molars in a 7
year old girl.
She complained
of hot and cold
sensitivity.
Her lower teeth.
These teeth had
repeated
restorations
from her dental
therapist and
dentist which
would often
fractured.
Note: the
normal white
enamel of her
other teeth
We extracted
these teeth.
Figure 3.
Figure 4.
Hypoplastic
primary second
molars in a 4
year old boy. At
the age of 18
months he had
measles which
most likely
contributed to
this enamel.
Hypoplastic
lower primary
second molars
in a 4 year old
boy.
Note: the rough
surface of the
reduced enamel.
Plaque and food
readily stick this
rough surface
leading to
decay.