L3- Tx on endo teeth Flashcards
(60 cards)
proper diagnosis and tx planning occurs?
BEFORE the RCT – this is critical
questions we ask before tx planning
- is it restorable?
how much coronal and radicular tooth structure is left?
is it periodontally sound?
what is the root morphology?
what is the condition of adjacent teeth?
s the tooth an abutment for a FPD or RPD?
main restorative options for endo treated teeth
- direct restoratino
- onlay (partial coverage restoration)
- crown (full coverage restoration)
success rates of psoterior teeth without coronal coverage
1 year– 96%
2 year – 88%
5 year – 36%
*SIGNIFICANT IMPROVEMENT CAN BE MADE IF PULPESS TEETH ARE CROWNED
purpose of the core
the objective of a core buildup is primarily to replace missing coronal tooth structure sufficiently to provide adequate retention and resistance for the crown that will eventually restore the function and the aesthetics of the tooth in the treatment
post indicated?
post is indicated where there is inadequate remaining coronal tooth structure to retain a core for an artifical crown
use post when? - general
ONLY WHEN NECESSARY
Three factors for good post
- apical seal
- proper length of post
- ferrule effect
success with post was hihest when?
with a parallel sided serrated post
effects of an adequate ferrule
- reduce ris of root fracture
- reduce risk of post fracture
- reduce ris of post and core dislodgment
- reduce failure of cement seal of artifical corwn
dimensions of ferrule
must be at least 1.5 to 2.0 mm of tooth structure apical to the core
post fractures share what similarities
all post fractures showed a smiliar pattern ot a lack of a ferrule effect of the metal collar at the CROWN MARGIN AREA AND A SHARP INTERFACE between the post and core
ways to increase the ferrule
- crown lengthening
- forced eruption
- subgingival prep
length of post related to success - general
longer posts = higher success rates
if the length of post = the length of crown – increased failure rate
25% increase in failure rate if the post was 1/4 the length of the crown
posts associated with vertically fractured enfo treated teeth
2/3 of them were a result of an extremely SHORT post terminating int the CERVICAL third of the roots
what stress increases a lot when shorter ferrule
shear stresses increased substantially as post length decreased
corwn length related to length of post in terms of force
if the crown is double the length of the post, the force of the crown is doubled in the root
ratio 1:1 to post and crown?
force is equal
if post is 1/4 lnegth of crown?
the force is multiplied by a factor of 4
saw a 25% failure rate (10 fold increase compared to 2.5 % failure rate when the length of the post = length of the crown
fracture toughness proportional to?
directly proportional to bulk
width of post?
if width of post exceeds 1/2 of the width of the root – the success rate is much lower
shape and stress in the post
if tapered post – stresses are in the cervical area
if parallel post – the stresses are more apical portions (concentrates stresses more apically)
apical seal with a post?
at least 4-5 mm of apical gutta percha MUST be retained in order to avoid reindection of the peri-apical region
ranking order of strength of core materials
- silver amalgam
- composite resin
- silver modified glass ionomer cement
