13. Restoration of the Endodontically Treated Tooth Flashcards
Introduction
• Special techniques needed to restore an endodontically treated tooth
• Usually considerable amount of tooth structure has been lost
– Due to:
• ____
• Endodontic treatment
• Previous ____
caries
restorations
Introduction
• Factors influencing technique choice
– Type of tooth
• ____, canine,
premolar, molar
– Amount of remaining ____ tooth structure
• Most important indicator in determining prognosis
incisor
coronal
Treatment Planning • Before being restored, endodontically treated tooth must be evaluated for: – Good \_\_\_\_ seal – No sensitivity to pressure – No \_\_\_\_ – No fistula – No apical \_\_\_\_ – No active inflammation
apical
exudate
sensitivity
Treatment Planning
Inadequate endodontically filled teeth should be re- treated before fixed prosthodontic treatment is begun
If doubt remains, the tooth should be observed for several ____
until definitive evidence of success or failure
months
Treatment Planning
• Microleakage studies show significant increase in microleakage at ____ months
– if endodontically treated tooth is left exposed to oral environment for 3 months or longer, recommend ____
3
endodontic retreatment
Treatment Planning
Must account for the ____ of the remaining tooth structure, weighed carefully against the ____ to which the restored tooth will be subjected.
Most of the failures are influenced by ____. As loading increases, failure rates ____.
strength
load
load
increase
Treatment Planning
• Cast post and core
• Prefabricated post and core
If sufficient tooth structure is present to support and retain a core build up, no ____ is necessary
post
Treatment Planning
• Cast post and core
– One-piece foundation restoration for an ____ treated tooth comprising a post within the root canal and a core replacing missing coronal structure to form the tooth preparation
– Two step technique
• post and crown ____ fabricated at same visit
Post and coronal portion prepared intraorally
One piece post and crown ____
Post is fabricated in the laboratory
Post and core is cemented
Crown is fabricated
endodontically
NOT
unacceptable
Treatment Planning
• ____
– A rod fitted into the prepared root canal of a natural tooth
– Provides ____ for the core
• ____
– Replaces any lost coronal tooth structure, allowing optimal tooth preparation geometry to be achieved
Post (dowel)
retention
core
Treatment Planning • Prefabricated post – Different materials for post – \_\_\_\_ – Fiber composite – \_\_\_\_ – Glass fiber --- ceramic and glass fiber for \_\_\_\_
– Different core materials » Composite \_\_\_\_ » Amalgam » \_\_\_\_ ionomer – Two step procedure
metal ceramic esthetics resin glass
Treatment Planning
Main Clinic
• Composite Resin Build Up Materials – Fluorocore (Dentsply)
• ____-releasing dual cure composite core build up material
– Clearfil DC Core (Kuraray)
• ____-cure, radiopaque, ____ component core build up material
fluoride
dual
two
Treatment Planning • Prefabricated metal post – made of different metals • \_\_\_\_ • Ni-Cr • \_\_\_\_ • Au-Pt • \_\_\_\_ • Stainless \_\_\_\_ wire – have high \_\_\_\_ and are very rigid – Main clinic: • \_\_\_\_ (Coltene) • Integrapost (Premier)
pt-au-pd co-cr ti steel modulus of elasticity parapost
Treatment Planning
• Fiber composite posts – Increase in \_\_\_\_ – Bundles of stretched aligned \_\_\_\_ embedded in resin matrix – Less stiffness and strength than \_\_\_\_ – Shorter \_\_\_\_ than metal posts – More easily \_\_\_\_ • If endo retreatment needed – Main clinic: • \_\_\_\_ fibre post 3D (3M) • Fluoropost system (Caulk,Dentsply)
popularity glass carbon fibers ceramic and metal longevity retrievable rely-x
Treatment Planning • Esthetic posts: – \_\_\_\_ posts (high strength ceramic) • Very strong and rigid – \_\_\_\_ composite – Woven \_\_\_\_ (polyethylene) posts • \_\_\_\_ and more flexible than ceramic – CAD/CAM • Impression scanned and digitized. Then \_\_\_\_ milled
zirconia ceramic fiber weaker zirconia
Treatment Planning
Literature Review
• Primary function of post is to provide ____ for the core
– Lovdahl and Nichols (JPD 38:507,1977)
• The strength of an endodontically treated tooth is directly related to the bulk of the remaining ____
– Hock (1976, masters thesis)
• No significant increase in resistance to ____ with the use of a post
retention
dentin
fracture
Post placement DOES NOT ____ teeth.
Studies have shown it provides no significant ____
strengthen
reinforcement
Disadvantages of Cemented Post
• Additional ____ procedure to place
• Removal of additional ____ structure to
accommodate post
• Difficult to ____ if failure
– ex. Inadequate core retention
• Complicates or prevents future ____ re-treatment
Only place post if need to retain ____
operative tooth remove endodontic core
Considerations for Anterior Teeth
• Endodontically treated anterior teeth do NOT always need full ____
– Depends on amount of remaining tooth structure
• Post is only recommended for teeth requiring ____
• If tooth discoloration, but tooth is intact, recommend attempt ____, first and direct ____
coverage
full coverage
bleaching
restoration
Considerations for Anterior Teeth
• When loss ofcoronal tooth structure is ____ or tooth will be ____ or ____ abutment, ____ mandatory
– Retention and support of core derived from within canal due to limited coronal ____
extensive
FDP
RPD
full crown
Considerations for Anterior Teeth
Endodontic access and small proximal lesions
Restore with ____ resin restorations
Endodontic access and large proximal lesions
____restoration needed to restore
composite
full coverage
Considerations for Posterior Teeth
• Subject to greater loading than anterior teeth
• Morphologic characteristics – Cusps can be ____ apart
– more susceptible to fracture
• Endodontically treated posterior teeth should receive ____ coverage to prevent fracture
– Gives best protection against fracture
wedged
cuspal
Considerations for Posterior Teeth
Minimal tooth destruction. No facial or lingual damage
>
Possible ____ with cuspal coverage or ____ coverage
Moderate to severe damage
>
____ build up or ____-core and crown for premolars/molars
Total coronal destruction
>
____-core and
crown, possible crown ____ for premolars/molars
onlay
full
core
dowel
dowel
lengthening
(1)Conservation of Tooth Structure (a)Preparation of Canal
Six Features of a Successful Preparation
Positive ____ stop (to minimize wedging)
Adequate apical ____
Adequate post ____
Minimum canal ____ (no undercuts)
Vertical wall to prevent ____ (similar to box)
Extension of definitive restoration onto ____ tooth structure
horizontal seal length enlargement rotation sound
(1)Conservation of Tooth Structure
(a)Preparation of the Canal
• Remove only minimal tooth structure from canal
• Excessive enlargement can perforate or ____ the root
– May ____ during post cementation or function
• Thickness of remaining ____ is prime variable in fracture resistance of root
• Photoelastic stress analysis has shown internal stresses reduced with ____ posts
weaken
split
dentin
thinner
(1)Conservation of Tooth Structure (a)Preparation of the Canal
• Root canal should be enlarged only enough to enable post to fit accurately and passively
– Enlargement generally accomplished ____ file sizes beyond largest file size
one or two
(1)Conservation of Tooth Structure (b)Preparation of Coronal Tissue
• Endodontically treated teeth often have a substantial amount of missing tooth structure
– ____, existing restorations, endo access
• Cast post and core requires substantial reduction which results in minimal coronal ____
– Need to remove undercuts for preparation
• Save as much ____ tooth structure as possible
The amount of remaining ____ is the most important predictor of clinical success
caries
dentin
coronal
tooth structure
(1) Conservation of Tooth Structure
(b) Preparation of Coronal Tissue
• Tooth preparation and loss of internal tooth structure for endodontic treatment results in ____, fragile tooth structure
– Often need to reduce this in ____
thin
height
(1)Conservation of Tooth Structure (b)Preparation of Coronal Tissue
Need to maintain as much coronal tooth structure as possible
Extensive coronal tooth structure lost. More forces are transmitted to ____
root
(1)Conservation of Tooth Structure (b)Preparation of Coronal Tissue
• Extension of axial wall of crown apical to
missing tooth structure provides ____
– ____ used to fit the root or crown of tooth instead of completely ____ core material
– Thought to help bind remaining tooth structure together
– Helps prevent ____ of an endodontically treated tooth
ferrule
metal band
encircling
fracture
(1)Conservation of Tooth Structure (b)Preparation of Coronal Tissue
• If unable to achieve ferrule effect or if less
than 2mm coronal tooth structure remains circumferentially, ____, ____, or combination is indicated.
crown lengthening
orthodontic extrusion
(1)Conservation of Tooth Structure (b)Preparation of Coronal Tissue
• Crown lengthening – A surgical procedure
to increase extent of ____ tooth structure for restorative or esthetic purposes by apically positioning the ____, removing supporting ____ or bot
supragingival
gingival margin
bone
(1)Conservation of Tooth Structure
(b)Preparation of Coronal Tissue
• Orthodontic
extrusion
– Movement of tooth beyond the natural ____ that may be accompanied by a similar movement of their ____
occlusal plane
supporting tissues
2)Retention Form
(a)Anterior Teeth
• Post retention affected by
– (A)Preparation ____ – (B)Post ____
– (C)Post ____
– (D)Post ____
– (E)____ agent
Simultaneous dislodgement of crown with post and core results from inadequate \_\_\_\_ form.
geometry length diameter surface texture luting retention
(2)Retention Form
(A)Preparation Geometry
• Different canals have different canal configurations
• Ideal post has ____ walls (minimal taper)
– Canals with CIRCULAR cross section
• Can accommodate ____ sided post
– Canals with ELLIPTICAL cross section
• Need some ____ to ensure retention and eliminate undercuts
• For parallel post, need to considerably enlarge canal which would ____ tooth
parallel
parallel
taper
weaken
(2)Retention Form (A)Preparation Geometry
• Post retention increases as vertical wall taper is ____
• Use of a parallel sided post in tapered canal requires considerable ____ of post space
reduced
enlargement
(2)Retention Form
(B)Post Length
• Post should be as long as possible without jeopardizing apical seal
– Ideal to maintain ____mm apical seal
– If post is ____ than coronal height of clinical crown, unfavorable due to possible root fracture
5
shorter
Post too short
- Inadequate ____
- Increased risk of root ____
Post too long
- jeopardizes ____
retention
fracture
apical seal
(2)Retention Form (B)Post Length
Risk of root fracture is greater with ____ dowel than long one
The longer dowel distributes the stress over a ____ area of bone-supported root
short
larger
(2)Retention Form (C)Post Diameter
- Increasing post ____ results in tooth weakening
- Controversial if increase in diameter increases ____
- Post diameter should NOT exceed ____ of cross sectional root diameter
diameter
retention
one third
(2)Retention Form (D)Post Surface Texture
• Serrated or roughened post is more ____ than smooth one
• ____ of post and root canal, increases
retention of tapered post
retentive
grooving
(2)Retention Form (E)Luting Agent
• Improved retention with adhesive resin luting agents – \_\_\_\_-containing root canal sealers • remove or etch (37%) for effectiveness of adhesive luting agent – Indicated if post becomes dislodged • Selection more important if \_\_\_\_ fit – If \_\_\_\_ or wobble, remake post
eugenol
poor
rotation
(2)Retention Form (b)Posterior Teeth
• Posterior teeth have curved roots and ____ or ribbon–shaped canals
– Retention better provided by two or more relatively ____ posts in ____ canals
ellipitical
short
divergent
(2) Retention Form
(b) Posterior Teeth
• When>3-4 mm of coronal tooth structure with reasonable wall thickness remains, use of a post in canal, not ____
– Reduces risk of ____
– Chamber must provide adequate ____ for the core
• Prepare ____ post spaces to extend core material
necessary
perforation
retention
short divergent
(2) Retention Form
(b) Posterior Teeth
Molars missing one or two cusps
– place one or more ____ posts with ____ condensed around it
• ____ canal maxillary molars
• ____ canal for mandibular molars
cemented
amalgam
palatal
distal
(2)Retention Form (b)Posterior Teeth
• Severely compromised molar missing 3 or 4 cusps
– Assess overall prognosis
– Fabricate ____
• Prepare post space and then, ____ space in another canal
• Possibly multiple piece ____ if different paths of withdrawal
cast post and core
shorter
interlocking
(3)Resistance Form
(a)Stress Distribution
• Influence of post design on stress distribution:
– Stresses are reduced as post ____ increases
– Glass fiber posts have ____ (flexibility) similar to dentin
• Lower stress concentration than ____
– ____ sided post distribute stress more evenly than tapered (wedging effect)
• However, parallel sided posts generate high stresses at ____
length elastic modulus metal or ceramic parallel apex
(3) Resistance Form
(a) Stress Distribution
• Influence of post design on stress distribution (continued):
– ____ angles should be avoided because they produce high stresses at apex
– High stress can be generated during ____
• Especially parallel-sided posts with no ____ for cement escape
sharp
insertion
vent
(3)Resistance Form
(a)Stress Distribution
• Influence of post design on stress distribution (continued):
– ____ posts not recommended due to high stress distribution in dentin
– ____ layer results in a more even stress distribution to the root with less stress concentrations
– ____ posts lead to lower stresses with less catastrophic failures
• fractures may occur in posts and not ____
threaded
cementer
glass fiber
(3)Resistance Form
(b)Rotational Resistance
• Rotational resistance in an extensively damaged tooth can be obtained by preparing a small ____ in the root canal
– Must be in ____ of post and core
– Locate where root ____
– Not needed if sufficient coronal tooth structure ____
groove
path of placement
bulkiest
remains
Anterior teeth
Adequate coronal tooth structure and favorable occlusal loading
>
Restoration into ____
Missing substantial coronal tooth structure
>
____**
Posterior teeth
Adequate coronal tooth structure
>
____ or other direct restorative material for core
Missing substantial coronal tooth structure
>
Cemented ____ and build up or cast post and core
access
cast post and core
amalgam
posts
Procedure • Endodontic therapy successfully completed – If \_\_\_\_, need re-treatment • Tooth preparation – Removal of root canal filling material to appropriate depth – Enlargement of canal – Preparation of coronal tooth structure
silver points
Procedure
• Calculateappropriate length of post
– Guidelines:
• Equal to height of anatomic crown (or 2/3 length of root)
• Leave ____mm of apical gutta percha, if possible (no less than 3mm)
– Apical 5mm may have ____ and ____ canals, which makes preparation difficult
5
curvatures
lateral
Procedure – Guidelines (continued): • If know working length, can calculate post length – Working length minus \_\_\_\_mm – If not, use \_\_\_\_ as guide • Apply \_\_\_\_ dam – Prevent aspiration
5
radiograph
rubber
Procedure
Removal of Endodontic Filling Material
• (1)Warmed endodontic plugger
– More ____mm consuming
– Eliminates possibility of ____mm damage
– May remove gutta percha immediately after ____mm
time
dentin
obturation
• Select an endodontic condenser ____ enough to hold heat
– Not too large to bind against ____
• Mark working length on ____
• ____ condenser and place in canal to soften gutta percha
large
canal
condenser
heat
Procedure Removal of Endodontic Filling Material • (2)Rotary instrument – \_\_\_\_ than warmed plugger – Possibility of dentin \_\_\_\_ and/or perforation
faster
damage
• ____ speed rotary instrumentation with specialized post preparation instruments
– Types
• Peeso-reamers
• Gates Glidden drills
– Results in small ____ in walls
• ____ softens gutta percha to follow canal
• Choose instrument slightly ____ than canal
slow
concavities
friction
narrower
Procedure
Rotary Instrument
• Be certain to follow ____ of gutta percha
– Do not cut dentin
• When gutta percha removed to appropriate ____, shape canal as needed
center
depth
• To shape canal – \_\_\_\_-speed drill • Same depth as initial length • Removes \_\_\_\_ • Prepares canal to receive post – \_\_\_\_ sided twist drill for parallel sided post • ParaPost • This is \_\_\_\_ and is NOT used to gain length • \_\_\_\_ to size of post
low undercuts parallel end-cutting widen
Procedure
Post Selection
• No more than \_\_\_\_ root diameter Root and walls at least \_\_\_\_mm thick • Knowrootanatomy – Prefabricated posts are \_\_\_\_ • Need more reduction with \_\_\_\_ canals to achieve circular shape
1/3
1
circular
ellipitical
Procedure Canal Enlargement • Know what type post system using – Decide based on clinical situation • Parallel-sided prefabricated posts – \_\_\_\_ prepared canals • Cast post and core – Excessively \_\_\_\_ canals
conservatively
flared
Procedure
Prefabricated Posts
• Use a prefabricated post that matches the size of the instrument to enlarge canal
• Be careful not to remove more ____
than necessary at apical extent of post space
dentin
• Verify post space preparation with ____
– Some practitioners believe if careful ____ techniques are utilized, radiograph is not necessary (?
radiograph
measurement
Procedure
Prefabricated Posts
• If a good fit is not achievable with a prefabricated post, a custom-made post is indicated
Custom posts indicated for teeth with root canals whose cross section is not ____ or is extremely ____
circular
tapered
Procedure
Prefabricated Posts
• Once post is adequately fitted, cement into canal with few ____ of post sticking out of tooth structure
– Post should not interfere with occlusal or ____ tooth reduction
• Place core build up
millimeters
axial
Procedure
Prefabricated Post and Core
• Fit matrix band, wedge, burnish contacts
– May need ____ band if little tooth structure
• Condense ____ or place composite resin or glass ionomer around post
• Fill pulp chamber and coronal cavity in conventional manner
• Shape and finish restoration to normal anatomical contour
• For amalgam, patient needs to ____ to prepare for crown
• For composite resin or glass ionomer, tooth could be prepared for crown at same ____
copper
amalgam
return
visit
Preclinic
Bonding Agent
Mix with ____ cure activator for dual cure resins
self
Procedure
Custom-made Post
• Need to remove ____ within the canal and then, perform additional shaping
undercuts
Procedure
Custom-made Post Preparation of Coronal Tooth Structure
• After the post space is prepared, the remaining coronal tooth structure is ____ for the crown
• Amount of reduction and margin design depends on type of ____ planned
– All ceramic, porcelain-fused to metal, or all metal
reduced
crown
Procedure
Custom-made Post Preparation of Coronal Tooth Structure
• Determine crown preparation design
• Ignore missing coronal tooth structure and
prepare tooth structure as if crown is intact
• Remove all internal and external ____
• Remove any unsupported tooth structure
– Try to leave walls minimum ____mm thickness
• Reduce wall height proportionally to wall
thickness
– Thin walls may fracture when interim restoration is removed or during seating of the casting
undercuts
1
Procedure
Custom-made Post Preparation of Coronal Tooth Structure
• Prepare part of remaining coronal tooth structure ____ to post for positive stop to minimize wedging and splitting of tooth
• Flat surface ____ to post to prevent rotation
• Anti-____ groove, if needed
perpendicular
parallel
rotation
Procedure
Custom-made Post Preparation of Coronal Tooth Structure
• Eliminate ____ angles and establish smooth finish line
• Determine if will fabricate
– ____ technique
– ____ technique
sharp
direct
indirect
Procedure
Custom-made Post Direct Technique
- For single canals with good clinical access
- Lightly lubricate canal and notch a loose-fitting ____ which extends full depth of canal preparation
plastic dowel
Procedure
Custom-made Post Direct Technique
• Using autopolymerizing resin, add in ____ with brush to dowel
• Seat in preparedcanal
• DONOTALLOW RESIN TO HARDEN FULLY IN CANAL
– Loosen and reseat several times when ____
bead
rubbery
Procedure
Custom-made Post Direct Technique
• Once resin has polymerized, remove pattern
• Form apical part of post by adding additional resin and reseating and removing post
– Do NOT lock it into canal
• Trim away ____ with
scalpel
• Post is complete when it can be inserted and removed without ____
undercuts
binding
• Slightly ____ core and let polymerize fully
• Shape core with carbide finishing burs or diamonds
– ____ spray
• Remove pattern and sprue or send to laboratory to sprue and cast
overbuild
water
Procedure
Custom-made post indirect technique
- For multiple canals or difficult access
- Use thin plastic pre- fabricated post or ____ wire, which fits loosely in canal and seats to end of preparation
- ____ post for retention (adhesive on ortho wire)
- Place ____ cord, if needed
orthodontic
roughen
retraction
Custom-made Post Indirect Technique
• With impression syringe, syringe ____ material into canal
• Seat plastic, roughened post into canal
• Continue to add impression material
around the prepared tooth
• Insert ____ tray
impression
impression
Procedure
Custom-made Post Indirect Technique
• Remove impression after setting complete
• Pour ____ cast, or send to laboratory to pour
• Laboratory will fabricate wax
pattern, invest and then, cast post and core
definitive
Procedure
Inserting Cast Post and Core
• Evaluate casting surface for nodules, etc.
• Cast post and core should fit somewhat loosely
– Prevent ____
• Should insert with ____
pressure
• ____ fit not as crucial as other cast restorations because crown will fit over it
fracture
gentle
marginal
Procedure
Inserting Cast Post and Core
• Luting agent must fill all ____ space within root canal system
• Coat post with cement
• ____ spiral is used to
fill canal with cement
– May need ____ to allow for escape of cement (especially ____ sided post)
• Seat post with gentle pressure
dead
lentulo
groove
parallel
Interim Restorations
• Endodontically treated teeth should be restored as soon as possible to avoid need for re- treatment
• temporary restorative materials (ex. ____) result in ____
• If cast post and core is made, the tooth will require a provisional restoration while the cast post and core is being fabricated
– Prevent ____ of teeth
– Support ____
– ____
ZOE microleakage drifting occlusion esthetics
Procedure
Provisional Restoration
• ____ wire or paper clip (?) fitted into canal and sticking out
• Preformed crown or vacu-form with ____ resin added with post in place
• Loosen and reseat while setting to avoid locking in
orthodontic
autopolymerizing
Procedure Provisional Restoration • Add more acrylic resin where needed • Adjust occlusion • Trim margins • Smooth and polish • Cement with \_\_\_\_
temporary cement
• Replacewithcleartooth • Reduce\_\_\_\_mmincisally • Toothlength – Approximately \_\_\_\_mm • Working length – Subtract 5mm from reference point • Approximately \_\_\_\_mm • Enlarge up to yellow parapos
5
21
16
Laboratory Manual 2018 Criteria for Evaluation
Cast Post and Core Preparation #8
• Gutta percha removed to correct length – Working length minus 5mm
• Internalundercutsremoved – Check with endodontic
explorer
• No root perforation
• Thin, unsupported dentin (
1
- 5
- 3
• Lingualshoulder-1mm
• Incisalreduction
– Preclinically, axial wall height should be no greater than ____mm
• Lingualclearance-1.5mm – May not be applicable
• Roundedinternallineangles
• CorrectF-LandM-Dangle
of convergence
4
Criteria for Evaluation
GC Pattern Resin Fabrication
• Internal aspect of post preparation adequately reproduced
• Fits to apical extent of post space
• Seats without resistance and
rotate
• Core ends with ____ in tooth preparation
• Core prepared to form of ____
• No voids, positive nodules, or deficiencies in resin pattern
• Crown preparation completed
butt joint
preparation
- Gutta percha removed to correct length – Tooth length: approximately ____mm – Working length: ____mm-14mm
- Post space prepared to correct diameter (yellow post)
- Internal anatomy of canal reproduced
- Post fits to apical extent of post space
- Post fits well and is not too loose or too tight
- Post space has adequate coronal length
- Retentive head of post is intact
18
13
- For endodontically treated teeth, preserving as much tooth structure as possible is important
- If a post is needed to retain the core, it should be of adequate length to retain core, but not jeopardize apical seal
- ____ instruments are the safest method to create a post space
heated
Summary • For anterior teeth – If largely intact, no \_\_\_\_ needed – Especially flared or elliptical canals, recommend c\_\_\_\_ – Prefabricated post and core can be used if adequate retention and \_\_\_\_ form – Esthetic post materials recommend if dark post would prevent fabrication of esthetic restoration
full coverage
cast post and core
resistance
Summary • For posterior teeth – \_\_\_\_ coverage needed prevent fracture – \_\_\_\_ may be used if minimal tooth structure missing – If extensive loss of tooth structure, \_\_\_\_ may be necessary
cuspal
core build up and no post
cast post and core
