13. Restoration of the Endodontically Treated Tooth Flashcards by J L

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

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Introduction
• Factors influencing technique choice
– Type of tooth
• ____, canine,
premolar, molar
– Amount of remaining ____ tooth structure
• Most important indicator in determining prognosis

incisor

coronal

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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

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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

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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 ____

endodontic retreatment

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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Post placement DOES NOT ____ teeth.

Studies have shown it provides no significant ____

strengthen

reinforcement

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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

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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

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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

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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

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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

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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

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(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

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(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

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(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 1. 5 1. 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

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