As a third year in dental school,
one of the most difficult tasks in clinic is gauging the longevity of certain
teeth. This past week in our Endodontics class we learned about cracked teeth
and the various prognoses for each type of crack that may result.
The first type of crack is the
fractured cusp. Patients with this type of crack in a tooth generally present
with pain upon release and this can be gauged with a tooth sleuth to determine
which cusp is the one in question. To treat this type of crack, remove the cusp
and restore the tooth. Root canal therapy is only necessary if the crack has
affected the pulp but otherwise the overall prognosis of the tooth is good once
it has been restored. The next type of crack is one that starts in the crown
and cracks the tooth mesiodistally. To treat, the crack must be prepared until
it is gone and a crown is likely to keep the tooth healthy. Again, root canal
therapy may be indicated based on the extent of the crack. If a cracked tooth
is untreated, it can lead to a split tooth in which the crack extends down to
the root and can separate the tooth in segments. If the crack extends on to the
root surface beyond a restorable area, extraction will then be necessary. A
third type of crack is the vertical root fracture. This starts in the root as
opposed to the crown and usually begins in a buccolingual direction. These
teeth almost always have had a root canal treatment prior. The only way to
treat these teeth is by extraction or removal of the fractured root (a root
amputation or hemisection may also be indicated).
The best way to diagnose any of
these types of cracks is first to use transillumination. This technique uses a
light and shines it directly onto the tooth from the lingual in order to see if
a crack exists in the coronal portion of the tooth. Taking a periapical
radiograph is also very useful in diagnosis of cracked teeth. Another valuable
tool is the periodontal probe. With cracked teeth, there will almost always be
a deep pocket where the crack arises; thus, probe around the tooth in question
and if you feel a deep pocket and the tooth was otherwise periodontally
healthy, a crack may have resulted. As with any type of dental pain, the
earlier you can treat it the better. Be sure to get these patients in as soon
as possible before their problems progress because once a tooth is extracted, a
patient’s dentition will never be the same again.