POST ENDODONTIC RESTORATION(Dr SAICHARAN)

CONSERVATIVE DENTISTRY AND ENDODONTICS

2. DR SAICHARAN
(SENIOR LECTURER)
DEPT OF CONSERVATIVE DENTISTRY AND ENDODONTICS
MAHE INSTITUTE OF DENTAL SCIENCES & HOSPITAL

3. INTRODUCTION
CHANGES IN ENDODONTICALLY
TREATED TEETH
TREATMENT PLANNING FOR
RESTORATION OF NON VITAL
TEETH
BASIC COMPONENTS USED IN
RESTORATION OF NON VITAL
TEETH
IDEAL PROPERTIES OF DOWEL
DOWEL CLASSIFICATION
RETENTION AND RESISTANCE
FORMS OF DOWEL
CORE MATERIALS
LUTING CEMENTS

5. There is greater deformation of a pulpless
tooth with an extensive cavity than in a
sound tooth under a similar load, because
a dead tooth contains about 9 percent less
water, which diminishes the elastic recoil
of the dentin. Therefore, there is a
potential risk for tooth fracture under
stress.
It is imperative that the risk of fracture be
foreseen and prevented, both during
endodontic treatment and subsequently.

6. CHANGES IN ENDODONTICALLY
TREATED TEETH
Loss of tooth structure
Altered physical characteristics
Altered esthetic characteristics

7. TREATMENT PLANNING FOR
RESTORATION OF
NON VITAL TEETH

9. IMPORTANT CONSIDERATIONS INCLUDE
The amount of remaining tooth structure
The anatomic position of the tooth
The functional load on the tooth
The esthetic requirements for the tooth
The various combinations of the above

10. AMOUNT OF REMAINING TOOTH STRUCTURE
Teeth with minimal remaining structure present several clinical
problems:
Increased root fracture risk
Greater potential for recurrent caries after restoration
Higher occurrence of final restoration dislodgement or loss
Increased incidence of biologic width invasion during
preparation

11. Biological width is defined as
distance measured from base of
gingival sulcus to the alveolar
crest. Average distance is
2.07mm.
Restoration impinging on
biological width will result in loss
of attachment and pocket
formation .

12. ANATOMIC POSITION OF THE TOOTH
Anterior teeth:
•Intact non vital anterior teeth that have non
lost tooth structure beyond access
preparation are at minimal risk for fracture.
They do not require a crown, core or a
dowel
•A non vital anterior tooth that has lost
significant tooth structure requires a crown

13. Posterior teeth:
•They carry greater Occlusal loads than anterior
teeth and restorations must be planned to
protect teeth against fracture.
•The functional forces against molars require
crown or onlay protection.
•When there is sufficient tooth structure to retain
the core and crown, dowels are not needed.
•If there is insufficient tooth structure to retain the
core and crown, dowels are mandatory.

14. FUNCTIONAL LOAD ON THE TOOTH
Abutmentteethforlongspan,fixed
bridgesanddistalextension,removable,
partialdenturesabsorbgreatertransverse
loadsandrequiremoreprotectionthando
abutmentssmallerbridges.
Teeththatexhibitextensivewearfrom
bruxism,heavyocclusionorheavylateral
functionrequirethefullcomplementof
dowel,coreandcrown.

15. ESTHETIC REQUIREMENTS
Anterior teeth, premolars and often the maxillary
first molar inhabit the esthetic zone of the mouth.
Teeth in esthetic zone require careful selection
of restorative materials, careful handling of the
tissues and timely endodontic intervention to
prevent darkening of the root as the tooth loses
vitality.

16. BASIC COMPONENTS
Post/dowel
core
crown

17. DEFINITION
•Post:Referstoacylindricalortaperedobject,
thatfitsintothepreparedrootcanalofatooth,
andissynonymouswiththetermdowelor
endodonticpost.
•Core:Referstoabuilduprestoration,usually
amalgam/compositeplacedinabadlybroken
downtoothtorestorethebulkofthecoronal
portionofthetoothtofacilitatesubsequent
restorationbymeansofanindirectextracoronal
restoration

18. IDEAL PROPERTIES OF THE DOWEL
Maximum protection of the root
Adequate retention with in the root
Maximum retention of the core and crown
Maximum protection of crown margin cement seal
Pleasing esthetics
High radiographic visibility
Retrievability
Biocompatibility

19. DOWEL CLASSIFICATION
Depending upon the preparation
–Custom made cast post and cores
–Pre fabricated post and cores
Metallic Non metallic
Non threaded threaded
ceramic
carbon fiber
fiber reinforced
resin

20. Depending upon geometrical configuration
•Tapered
•Parallel
Depending upon surface configuration
•Smooth
•Serrated
•Threaded

21. Commercially available post systems
Tapered, smooth-sided post systems
Eg: Kerr Endopost.
Parallel sided, serrated post systems.
Eg Whaledent parapost
Tapered, self threading post systems.
Eg: Dentatus screw.
Parallel-sided, threaded post systems.
Eg Radix anchor. Kurer anchor.
Parallel-sided, threaded, split-shank post
systems. Eg: Flexipost

23. INDICATIONS
Anterior teeth
•Where the natural crown of a root filled tooth either has
been lost, or is extensively damaged.
•Where the root filled tooth is to be used as a bridge
abutment
•Where a change in axial position greater than 1 mm is
required
•A crowned anterior endodontically involved tooth to
reinforce the crown covered tooth at cervical area
susceptible to fracture
•Loss of two proximal surfaces with a lingual endodontic
access opening which weakens the tooth .

24. Posterior teeth:
•Indicated, when the remaining coronal portion is less than 50%
and sufficient long thick root structure is present.
•Indicated when the root filled tooth is to be used as an
abutment for a bridge.
•In case of malposed teeth, when preparation of tooth would
cause exposure of the pulp.
•Indicated is restored bicuspids which are endodontically
involved.
•Shortened tooth due to the nature of destruction or removal of
undermined, undesirable tooth structure
•Where there is a vital tooth with insufficient retention for a
conventional crown

25. CONTRAINDICATIONS
oSevere curvature of the root
oPersistent periapical lesion
oPoor periodontal health
oPoor crown to root ratio
oWeak / fragile roots
oTeeth with heavy Occlusal contacts
oPatients with unusual and occupational habits
oEconomic factors
oInadequate skill

26. RETENTION FORM
oPost design
oPost length
oPost diameter and remaining dentin
oSurface preparation of the post and canal
oCement placement
oLuting cements

27. RETENTION FORM
oPost design
Active threaded > Passive parallel > passive tapered.
oPost length
More the length, more the retention
Ideally, length of post = Crown Length or at least 2/3-3/4 the length
of root
oPost diameter and remaining dentin
–Conservative
–Proportionist
–Preservationist
More the diameter more is the retention but more is the fracture
susceptibility as well.
Ideally d <
1
/
3cross-sectional d of root

28. RETENTION FORM
•CONSERVATIONIST approachadvocatesminimalcanal
preparationandmaintainingasmuchresidualdentinas
possible,therebysuggestingrestrictionofthepostdiameterin
anefforttoconservetheremainingtoothstructure
•PRESERVATIONIST—the post should be surrounded by a
minimum of 1 mm of sound dentin.
•PROPORTIONIST—Stern and Hirshfeld suggested that the
post width should not be greater than the root width at its
narrowest dimension. This proportionist approach was
advocated with the intent of saving sufficient tooth structure

30. RESISTANCE FORM
oFerrule effect
oVertical remaining coronal tooth structure
oAnti rotation
A groove / notch at the orifice of canal in the region of max bulk is
placed. Then is called as anti-rotational notch/groove / element or
keyway

31. FERRULE EFFECT
oAferruleisdefinedasabandofextracoronalmaterialatthe
cervicalmarginofacrownpreparationthatencompassesthe
toothandprovidesresistanceformtothetooth.Thisis
usuallyprovidedbythecrownthatisplacedoverthepostand
coresystem
oOneto2mmoftoothtissuecoronaltothefinishlineofthe
crownpreparationsignificantlyimprovesthefracture
resistanceofthetoothandismoreimportantthanthetypeof
coreandpostmaterial

33. REMOVAL OF ENDODONTIC FILLING
MATERIAL
oThe timing for removal of GP is still controversial.
It was previously believed that 24 hours to a week
delay was required to avoid disturbing the seal.
Recent reports reveal that adequately condensed
GP can be removed immediately.

34. CORE MATERIALS
•Cast core
•Amalgam core
•Composite resin core
•Glass ionomer core
•Resin modified glass ionomer core

35. IDEAL REQUISITES FOR CORE MATERIAL
•High compressive strength
•Dimensional stability
•Ease of manipulation
•Short setting time
•Ability to bond to both the tooth and pos
•Adequate rigidity of core material
•Chemical stability
•High radiopacity
•Biocompatibility
•Inexpensive

36. CAST CORE
Acastmetaldowelandcoreisatraditionalway
torestoreendodonticallytreatedteeth.Thecore
isaninterregnalextensionofthedowel

37. Advantages
Noble metals are non corrosive
High strength and rigidity
Disadvantages
Higher rate of root fracture
Financial cost of this service is high
Two appointments are needed and laboratory
expenses is significance.

38. •Thecustom-castpostandcoreisrecommended
whenevermorethanthree-fourthofthecoronal
toothstructureislost.
•Theprefabricatedpostandcoresystemsare
recommendedwhenthelossisrestricted
betweenone-halfandtwo-thirdofthecoronal
toothstructure.

39. CLINICAL RECOMMENDATION
• Glass fiber–reinforced epoxy resin post system → More
than one-half coronal tooth structure loss
• Metal post system → More than two-third coronal tooth
struc ture loss

40. AMALGAM CORE
It is a traditional core build up material with a long
history of clinical success
Advantages:
High compressive and tensile strength
High modulus of elasticity
High stability to thermal and functional stresses
Easy to manipulate
Dimensionally stable
Contrasting color to tooth

41. DISADVANTAGES
Significant potential for corrosion and
subsequent discoloration of the gingiva or
remaining dentin
High coefficient of thermal expansion
Does not adhere to tooth structure
Slow setting time –requires separate
appointment for core build up and tooth
preparation

42. COMPOSITE RESIN CORE
Advantages
High compressive strength
Reliable bond to tooth structure
Command set nature to allow immediate tooth
preparation
Radiopaque
Ease of manipulation

43. DISADVANTAGES:
•High coefficient of thermal expansion –
potential for microleakage
•It is not dimensionally stable in wet
environment
•Water sorption –absorbs water –core
expands –composite dries –core shrinks

44. GLASS IONOMER CORES
•Glass ionomer and glass ionomer silver are
adhesive materials useful for small buildups or
to fill undercuts in prepared teeth.
•Indications:
•It is indicated in posterior teeth:
–in which bulk of a core material is possible
–Significant sound dentin remains
–Additional retention is available with pins
–Moisture control is assured
–Caries control is indicated

45. ADVANTAGES
Adhesion
Anticariogenic property-fluoride release
Radiopaque
Contrasting color to tooth
Coefficient of thermal expansion similar to tooth
structure

46. DISADVANTAGES
Low compressive and flexural strength
Low fracture toughness

47. RESIN MODIFIED GLASS
IONOMER CORE
Resinmodifiedglassionomermaterials
areacombinationofglassionomerand
compositeresintechnologies;theyexhibit
propertiesofboththematerials.

48. Advantages
•Bond to tooth structure
•Exhibit moderate strength greater than glass
ionomer and less than composite resin
•Adequate for moderate –size build ups
•Anticariogenic property
Disadvantages
•Strength still not adequate as core buildup
•High hygroscopic expansion
•High solubility

49. LUTING CEMENT
Cementation plays a significant role in
enhancing retention, stress distribution, and
sealing irregularities between the tooth and the
post.
The most common luting agents are as follows:
• Resin luting cement
• Glass ionomer cement (Type I)
• Resin-modified glass ionomer cement
• Zinc phosphate cement

50. Zinc phosphate cement and Type I GIC cement have been
successfully used for the cementation of posts for many years.
The current trend is to employ resin luting cement.
Advantages of resin luting agents are as follows:
• Increased retention
• Strengthening of the root (short term at least)
• Reduced leakage
• More resistant to cyclic loading
• Ability to bond with resin-based posts to form one unit
(monoblock)
Disadvantages of resin luting agents are as follows:
• More technique sensitivity
• Proper cleaning and etching of the canals which were
obturated with eugenol-containing sealers is important to
ensure proper polymerization
• The steps of bonding the post with such auto cure or dual cure
resin cements should be performed carefully and quickly