Operative dentistry aje qualtrough, jd satterthwaite la morrow, pa brunton

Making a decision
Whether or not to perform elective devitalisation should not be an
empirical decision but each tooth should be assessed individually.
Such assessment should include not only a careful clinical examina-
tion regarding current status of the tooth, but also the history of the
tooth. Radiographs and sensibility (vitality) testing are essential aids.
The aim of assessment is to determine the risks involved in not devi-
talising the tooth, primarily with respect to the chance of requiring
root canal treatment once the definitive restoration has been placed,
compared with the increase in complications such as failure of the
root canal treatment and potential for higher failure of the tooth or
restoration itself.
In situations in which elective devitalisation is being considered,
alternative treatment options should be explored. Such options may
include surgical crown lengthening, orthodontic movement or use of
a bonded restoration. Advances in multi-purpose bonding systems
may allow for placement of restorations (direct or indirect) whereby
retention is provided solely by the bond to tooth structure. Although
little long-term clinical data exist for this technique it has obvious
advantages if the longevity of the tooth can be increased.
There will be situations in which significant doubt exists over the
potential for continued vitality of a tooth or when a restoration cannot
be placed without utilising radicular dentine to provide retention.
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Careful planned elective devitalisation and appropriate restoration
may prove wise in such instances.
RESTORATION OF THE ROOT-FILLED TOOTH
Once a tooth has undergone endodontic treatment it is then necessary
to restore the tooth in order to:
• Provide a coronal seal (this has a significant effect on the outcome
of the endodontic treatment)
11,12
.
• Return the tooth to function.
• Protect the remaining tooth from fracture.
In most instances, teeth that have undergone endodontic treatment
will be doubly weakened. By the very nature of factors resulting 
in loss of vitality, the majority of endodontically treated teeth will
already have suffered from a significant loss of tooth structure as a
result of the cumulative ravages of caries and previous restoration. 
To enable endodontic access these already weakened teeth then have
a significant further amount of tooth structure removed. In addition, 
it has been suggested that endodontically treated teeth are more 
brittle. More recent studies dispute this, though some change in 
physical properties do occur.
Anterior teeth
In anterior teeth, the amount of tooth structure removed to gain access
to the pulp space is not overly large and does not have a large effect 
on the fracture resistance of the tooth. Thus for most anterior teeth, 
the only restorative need is to provide a coronal seal and return to
function. In many cases this may be achieved simply by removing the
obturant (gutta-percha) to a level slightly below the gingival margin
or cemento-enamel margin, placing a ‘sealing’ material (such as a
resin-modified glass-ionomer cement) 1–2 mm thick and then restor-
ing the access cavity with a resin composite (Fig. 4.2). Where the 
existing loss of tooth structure is extensive, more attention should be
given to the retention of the ‘core’ restoration and an indirect restora-
tion such as a full coverage crown should be provided.