It has been clearly established that the length of
extra-oral dry time and the stage of root development
are the most critical factors associated with root
resorption.
The critical dry time where a statistically
significant increase in root resorption was observed
was 15 minutes in one study although just five minutes
of dry time was sufficient to increase the incidence of
resorption in another study.
Teeth that are replanted
immediately have the best long-term prognosis and the
least incidence of root resorption.
One animal study
has suggested that removal of a
non-vital periodontal membrane with solutions such as
sodium hypochlorite may slow the rate of resorption in
teeth for which replantation has been delayed (e.g.,
more than 60 minutes), but the findings of this study
have not been corroborated in human material. The
International Association for Dental Traumatology
does not recommend pre-soaking in sodium hypo-chlorite
but it does suggest that the roots of avulsed
teeth with delayed replantation times (more than
60 minutes) should be scrubbed clean with gauze to
remove necrotic material and that the teeth should then
be soaked in a 2% sodium fluoride solution for
20 minutes before replantation in order to help delay
the inevitable onset of replacement resorption and
ankylosis.
If replantation has been delayed, endodontic therapy
can be commenced after replantation in mature teeth
but, for technical reasons, there may be an advantage in
carrying out the endodontic therapy prior to
replantation in teeth with open apices and which have
experienced long delays (greater than 60 minutes)
before replantation.