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

REPLACEMENT AND REPAIR OF RESTORATIONS
Failed or defective restorations that are associated with a clinically
significant loss of function, tissue inflammation, or pulpal pathology
should be replaced, adjusted or repaired (if possible), providing such
treatment can be expected to overcome the problem. Surface quality
deficiencies alone do not constitute an adequate reason for replace-
ment
14
. It must be remembered that the cyclic replacement of restora-
tions is associated with loss of tooth tissue due to progressive cavity/
preparation enlargement and repeated insults to the pulp.
In recent years there has been a shift towards maintenance and
repair
15
, rather than the replacement of the deteriorating yet service-
able restorations in patients who maintain a good standard of oral
hygiene. These patients with favourable oral environment and low
caries risk should receive minimum intervention.
As a clinician, one must be able to:
• Diagnose a failed restoration.
• Analyse the reason for failure.
• Design the repaired/replacement restoration.
• Efficiently remove failed restorative material.
• Apply/insert corrected restoration.
Management decision
Although a fault may be identified, operative interference may not be
warranted. A minor defect of a restoration margin with no signs of
caries due to microleakage is a serviceable restoration. All operative
interventions carry risk of additional damage to remaining natural 
tissues and intervening in a situation such as this will result in unwar-
ranted removal of healthy tooth structure. Where minor defects have
occurred, it is often possible to adjust local features and avoid radical
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Maintenance of the restored dentition


157
reconstruction for example, clear occlusal interference and remove
ledges from restorations or make minimal marginal additions.
When a fault is present but is localised to one region of the restora-
tion, then consideration should be given to repairing rather than
replacing the restoration, such that the intervention is minimised.
Similarly, when caries is present adjacent to a restoration margin, then
considering the lesion as a new/primary lesion and providing a
localised repair will also act to preserve the health of the tooth.
Although evidence for survival of repaired restorations is sparse,
there are reports of good short-term survival rates
16,17
. When possible
the observable defect should not only be corrected but preventive fac-
tors established to reduce the incidence of recurrent problems. When
such additions/repairs can be made the new preparation should be
designed to be as much as possible within the old restoration and
shaped so that it will afford sufficient extension to:
• Eradicate the old defect.
• Permit adequate operative access when inserting the new 
restoration.
• Provide sufficient resistance and retention form to retain the new
restoration.
Removal of an entire restoration that has a fault may be necessary;
however such radical retreatment must be undertaken in the light of
cost–benefit analysis, which includes the strategic value of the tooth
and the anticipated service life of the new restoration. During the
removal of the old restoration, sectioning of fragments of the restora-
tion rather than removing every bit (with attendant problems of time,
vibration, visibility and over-extension) will help to minimise the
amount of healthy tooth structure lost. The failed restoration should
be studied to identify effective planes of section, for example, across
the isthmus of old compound amalgams followed by sagittal section-
ing of both key and box, thereby allowing the remaining pieces to 
‘fall into’ the body of the preparation for convenient extrication. 
Care should be taken when prising any remaining adherent pieces 
of the restoration from the preparation walls as excessive leverage
may result in cusp/wall fracture. Replacement restorations are 
subject to the same principles of preparation design and associated
operative techniques in their placement as are deployed for primary
restorations.
In all cases in which a restoration is to be repaired or replaced, the
likely cause of failure should be identified, the preparation modified
and, if appropriate, the local environment modified (e.g. by removal
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Chapter 7
of non-working interferences on the tooth/restoration in question) in
order to ensure maximum life of the new restoration. In all cases, the
preparation should be reassessed to consider its potential for clinical
effectiveness, in some cases an extended, indirect or full-coverage
restoration may be indicated. Blind repetition of the initial operative
approach is likely to be followed by ignominious repetition of failure.