Restoration of the Endodontically Treated Tooth Flashcards
what should you look for in a clinical assessment of an endodontically treated tooth
coronal seal
amount of remaining tooth structure
is the tooth restorable
swelling
sinus
TTP
buccal sulcus
mobility
what should you be looking for on the radiograph of an endodontically treated tooth
root filling - length, quality
unfilled/ missing root canals
shape of canal
patency
bone support
crown to root ratio
how often should you follow up with PA assessment of a RCT tooth
every year
how often should you follow up with PA assessment of a RCT tooth
every year
what are the problems after RCT
massive loss of dentine and tooth structure - internally and externally
wide post holes
fractured instruments/ perforations/ curved canals
what is ferrule
no tooth preparation above the gum - 2mm of dentine above gingivae
are RCT teeth more likely to fracture
because there is a massive loss of dentine they are more likely to fracture
are RCT teeth as hard as non-root treated teeth
dentine hardness is not altered
does dehydration affect the hardness of a RCT tooth
no it doesnt weaken strength or toughness
what is coronal microleakage
ingress of oral-microorganisms into root canal system
what should happen generally to root filled teeth that are left unrestored for 3 months
they should be re-root canal treated
how do you create a coronal seal
trim GP to the access cavity and place RMGI over pulp floor and root canal openings
if its a small access cavity (eg lingual/ palatal of anteriors)
composite restorations
what restoration would be required for an anterior tooth missing marginal ridges
post crown
what is the main indication for direct post restorations
ferrule present
what is an indication for cast post and cores
no ferrule - no dentine above the gum level
what is a disadvantage of doing a cast post crown on a tooth with no dentine above the gum level
its not stable and can rock when patients bite and can loosen the cement and cause bacteria ingress
what is a post/ core
gains intraradicular support for a definitive restoration
the core provides the retention for a crown
post retains the core
do posts strengthen or reinforce the tooth
no preparation of the root canal for a post weakens the tooth
what is the post
placed in the root canal
what is a core
what the prosthesis is cemented to - eg crown or bridge abutment
what is required for post placement
incisors and canines
avoid in mandibular incisors due to thin roots
avoid in curved canals to avoid perforations
what is the root filling length for post placement
4-5mm apically
what should the width of the post be
no more than 1/3 of root width at narrowest point and have 1mm of remaining circumferential coronal dentine
how much alveolar support is needed for a post
at least half of the post length into the root
what is the requirements for a ferrule
at least 1.5mm height and width of remaining coronal dentine
how is a ferrule described
dentine collar
what are the advantages of retaining a ferrule
prevents tooth fracture
prevents root fracture
why should posts be parallel sided
avoids wedging in the tooth
more retentive than tapered
why should posts be non-threaded
smooth surface incorporated less stress to remaining tooth than threaded
why should posts be cement retained
less retentive than threaded posts but cement acts as buffer between masticatory forces and post/ tooth
what are the three classifications of posts
manufacture
material
shape
what is the manufacture class of posts
pre-formed/ pre-fabricated or custom made
what materials are used to make posts
cast metal, steel, zirconia, carbon/ glass fibre
what shapes can pots be
parallel sided or tapered
what are the classifications of pre-fabricated posts
tapered smooth
tapered serrated
tapered threaded
parallel smooth
parallel serrated
parallel threaded
what are advantages of using prefabricated posts
only 1 visit required
no impression and lab visit required
chairside core build up
what are custom posts
cast from direct pattern fabricated in patient’s mouth
how is a custom post manufactured
unified post and core made in one piece with the same material
what are the properties of a metal post material
poor aesthetics, root fracture, corrosion, cant use if patient has nickel sensitivity, radiopaque on radiographs
what are the properties of ceramic post materials
high flexural strength and fracture toughness, favourable aesthetics, difficult retrievability and root fracture common
what are the properties of fibre post materials
flexible, similar properties to dentine, aesthetic, retrievable, bond to dentine with DBAs, radiolucent
what s a core build up
the internal part of the tooth is build up with restorative material to replace the lost tooth tissue
what does the core build up provide
retention and resistance for definitive restorations
what are the three common core materials
composite
amalgam
glass ionomer
what are the properties of using composite as a core material
tooth coloured, good aesthetics, bonds to tooth structure, technique sensitive, moisture control required
what type of post is a composite core usually used with
fibre post
why are amalgam cores tended to be avoided
retention is required and poor aesthetics and have to leave for 24 hours to set
why are glass ionomer cores not favourable
absorb water and core expands in size
what is a Nayyar core
they cut a bit of the coronal GP away and replace it with amalgam to increase retention
what is the difference between inlay and onlay
inlays - the cusps are not covered or supported whereas with onlays the cusps are supported
how to determine if a tooth needs a post
could you build up a core
does the tooth need a post now
what factors should you consider when designing the restoration post RCT
how long will post be
have you got a ferrule
how wide
3-5mm remaining GP
is canal straight
how much space needed for the core
what degree of taper should you have in your canal
6 degree
how do you fit a post
do not fill post space with cement
use firm apical pressure
get rid of excess
ask lab for provisional acrylic crown
name four problems with posts
perforation
core facture
root fracture or crack
post fracture
what is the management for post perforation
repair - internal or external (periradicular surgery)
extraction
how are posts removed
ultrasonics
masseran kit
eggler
moskito forceps
what are the reasons by percentage why posts fail
60% due to restorative reasons
32% due to periodontal problems
8% due to endodontic reasons
do all RCT teeth need a post and crown
no - can do onlay or composite build up
why are unified post and core preferred for non vital teeth
it avoids material interfaces
do all cores need a post
no
