Re: HOW DOES THE BAD POST ENDODONTIC RESTORATION LEAD TO FAILURE

[Anonymous]

Most clinicians forget that our job of saving a tooth does not end with giving a good rc treatment.It s success is equally dependent on the post-obturatopn filling as well as the crown given to safeguard the tooth.
The long-term prognosis for a root canal treated tooth depends on the endodontic treatment
as well as on the post-endodontic restoration
The objectives for the restorative measures after filling the root canal are to restore the
function, create a bacteria-proof closure, and contain the fracture risk.
The question whether or not the loss of pulp including the blood vessel system would
cause a tooth to dry out and thus increase the risk of fracture was discussed for a long
time. However, numerous studies showed no change of the hard tissue’s physical properties
after a vital extirpation and subsequent endodontic treatment. The fracture risk of an
endodontically treated tooth is mainly due to the trepanation-based loss of the pulp cavity
roof. The root canal and post bed preparations also contribute, though on a minor scale, to
the reduction of the hard tissue and thus to weakening the tooth.
The indication for the restoration of endodontically treated teeth with posts has undergone
a significant change in recent years . While a restoration including a post build-up
used to be considered a stringent indication in the past, today many dental professionals
agree that rather the amount of remaining hard tissue is the decisive factor for a root post
application
More simply phrased, for front teeth and premolars an intraradicular cementation of the
restoration is required if only two coronal dentine walls remain. If the remaining two dentine
walls on molars are less than 3mm high and only a flat pulp cavity exists with insufficient
retention surface for an adhesive restoration a root post is indicated as well
As far as a bacteria-proof closure is concerned a post-endodontic restoration should be
performed without delay. This requirement also takes into account the procedure for a
planned post insertion. For one, temporary luting cements cannot sufficiently prevent a
re-infection of the endodont through saliva, and secondly, temporarily cemented posts
increase the risk of a longitudinal fracture. Glass fiber enforced composites make it possible
to begin reconstruction immediately following the root canal filling, thus fulfilling the
above-mentioned requirement.