hi everyone in this video we'll be covering the principles of restoring root treated teeth
talking about posts customer coverage cool materials and answering a question that's
frequently asked which is how long do we wait before restoring root treated tea
so just before we get started we'd like to thank dr kushal Ghadia who is a consultant
in restorative dentistry and a specialist in periodontology orthodontics endodontics
restorative dentistry and has a special interest in dental implantology dr guardia has been kind
enough to provide this content from ace courses and while this video is only a summary the full
webinar is available for students completely free of charge on his ace courses website root treated
teeth are more brittle and excess cavities weaken teeth depending on how much tooth tissue has been
lost you have about twenty percent weakening if the occlusal surface has been lost a forty
percent weakening if you've lost mesial buckle or distal occlusal surfaces and a 60 weakening
for an mod this varies based on the extent of the ridge lost if the functional cost has been lost or
if the patient has a parafunctional habit we need to do something to restore the strength at the end
of the root canal treatment the more dentine that is lost the more likely that a root filled tooth
will fracture it's also important to note that as you use irrigance during endodontic treatment
these irrigans change the physical properties of the teeth by decreasing the flexural strength of
the dentine and increasing the brittleness the survival of a tooth is reduced by five things
one the loss of both marginal ridges two if the tooth is used as an abutment tooth for a fixed
or removable prosthesis this by the way should not be done because we'll end up compromising the root
treated tooth due to its inability to cope with as much load as a sound tooth three if it's a molar
four narrow deep probing defects which indicate the presence of a crack or a fracture and finally
five if there in fact is a crack the more of these you have the worse the prognosis for the tooth
the first principle we're going to be talking about is to preserve as much tooth structure
as possible so wherever you can do an online instead of a crown it is increasingly believed
that the ability of a root filled tooth to resist the fracture is directly related to the amount
of tooth tissue remaining the more tooth tissue remaining the less likely it is to fracture but
we should also be aiming to reduce the amount of stress that the tooth will endure the second
principle to discuss is about replacing the old restoration before carrying out your root canal
treatment if someone presents with a previous restoration an mo composite or amalgam or a
previous crown for example and there's a need to root canal treat the tooth you should remove the
previous restoration even if it looks clinically and radiographically sound the reason for this
is there is a 65 chance that there is secondary carries present underneath so you should remove
the old restoration or the old crown instead of accessing through it clear the carries and then
build it back up with good margins before starting your ender the third principle we'll talk about is
ensuring that the patient is pain free before obturating favoring doing endodontics over two
appointments instead of one so if your patient attends for your obturation appointment but they
were still in pain you should do more chemical debridement put more medication down the canals
close to the working length temporise and send the patient away before reviewing them ensuring they
are symptom-free before bringing them back in for obturation the fourth principle is to provide a
good coronal seal there has been controversy over what is more important the root canal treatment or
the quality of the restoration afterwards a 1995 study supports the claim that it's the restoration
after which determines the prognosis of the tooth you might have come across a patient with
a not so great root treated tooth but they'll tell you they've had no problems with the
tooth for over 20 years in this case without any doubt they would have had an amazing coronal seal
however later in 2000 there was evidence to show that both a good root canal treatment and a high
quality restoration were both important that said you should aim to do both well but if
for whatever reason the root canal treatment didn't go exactly as you would have liked then
it's really important to make sure that you've got that optimal coronal seal otherwise the endo
will just fail the fifth principle we will speak about is the necessity of a pharaoh the 1.5 to 2
millimeters of coronal dentin all the way around the tooth and most importantly at the functional
load-bearing areas without the ferrule effect the crown would have less resistance to fracture loads
and will dislodge quite easily for example if a maxillary incisor which has a crown had
forces occluding labially from an occluding mandibular incisor the path of dislodgement would
be in the labial direction to reduce this you should increase the ferrule on the palatal aspect
of the upper incisor by preparing the surface equi gingivally instead of super gingivally and
those extra couple millimeters will provide you with a significant difference in resisting those
occluding forces this way it's still cleansable but also provides you the greatest amount of
retention and resistance to those labial forces reducing the likelihood of dislodgement when the
lower incisor is in function or when a person goes into anterior guidance this is an example
to help you visualize the importance of feral in the functional load-bearing areas especially
now let's move on to posts for posts three millimeters of root structure apically
should improved fracture resistance for teeth restored with the post and core
it's important to note that posts serve no purpose other than to hold their core they don't reinforce
the teeth instead to actually weaken them and long and parallel posts are generally better than
tapered and screw posts the ferrule of 1.5 to 2 millimeters is needed and the greater the height
the greater the resistance features that you will have with the crown posts can be prefabricated or
cast in a lab you would use a cast post if you wanted the post to be customized to the shape
of the canal and this is beneficial when you have a really large canal and you want it to
limit dentine removal with a prefabricated post on the other hand you need to prepare the dentine
in the canal to match it to the shape of the post this can be really destructive especially
in large canals the disadvantage of using a cast post is that you'll need a temporary
post while the lab makes your customized post and your temporary post can't provide the same
hermatic coronal seal that a prefabricated post and core can provide however there are a couple
ways to reduce the likelihood of the invasion of microorganisms during this temporarization period
while the lab fabricates your post the first one is to cut back the gpu two millimeters further
than where you want your post to be and fill the canal with two millimeters of irm by doing this
you're creating an extra seal the second thing is to do some immediate dentin sealing we won't
get into all the benefits of ideas today and hopefully we'll cover it in a future video
but for now if you're unfamiliar with what ids is there's some great evidence-based content online
that you should check out and we'll leave some links in the description for you to have a read
very briefly it's when you sandblast etch prime and bond to seal the dentine instead of keeping
the dentin exposed between the time that you temporize and fit the definitive restoration
so then do all root treated teeth need caspal coverage for anterior teeth if the only tooth
tissue lost is that of the access cavity or the access cavity and some proximal tissue then a
composite restoration would probably be sufficient however if there's an access cavity or multiple
restorations or a very large restoration then a full coverage crown would be needed for premolar
teeth there's a bit of a gray area but this should give you some guidance on what you should be doing
depending on the presentation pause the screen to have a look for molars you should almost always be
providing customer coverage one scenario where you don't need to provide classical coverage
is when you have a very conservative access and it's completely intact otherwise and when we see
it very conservative here we're referring to an optimal isthmus width of less than a third
of the tooth tissue removed between the cusps if there is any more than a third of the tooth tissue
lost between the buccal and paleto cusp or if there is a ridge or a cusp missing then you will
need customer coverage this paper shows that root treated posterior teeth are six times more likely
to be lost if they didn't have customal coverage as compared to if they did have classical coverage
so you can choose to place a naiar core with amalgam or you can place a composite core
and each have their advantages and disadvantages for an ir core you can
prep two to four millimeters into the canal and again use a two millimeter irm plug which will
provide an extra seal in the canals beneath that nio core however an amalgam restoration will shine
through so if you're planning for an aesthetic restoration like an emax crown or if you intend
on having a bonded restoration it would be preferable to do it with a composite core
ng ital in 2008 said that there are four things which significantly improve the outcome of primary
root canal treatments and they are shown on the screen now the fourth on the list is a final
coronal restoration we should all consider the immediate coronal seal as the final part of the
root canal treatment and this links back to making sure that the patient is symptom free before
obturating it shouldn't be the case that you have obturated and the patient is still in pain
and now you're waiting for them to get out of pain before doing the coronal seal instead this
coronal seal should be done immediately after the root canal treatment okay guys we hope you
guys found that video useful and if you did we'd really appreciate if you gave this video
a like and subscribe to our channel there are more videos like this coming soon in line with
the ace courses webinars created by dr guardia for the full webinar make sure you check out
the ace courses website which is completely free for students to use there are lots of webinars on
there on dentures occlusion tooth surface loss and much more there's a link in the description
to sign up if you haven't already and we'll see you in the next video thank you for watching