the prosthetic options and treatment planning, method, techniques of fabrication and impression making and restorting endodontically treated teeth

1. Vinay PavanKumar K
2nd year MDS
AECS Maaruti College of Dental Science and
Research Centre

2. Procedure
Historical
perspective &
Rationale
Post fabrication
Core fabrication
Selection of post
Interim Types of post

3.  Ikram OH etal compared the volume of hard tooth tissue lost
after caries removal, access cavity preparation, root canal
preparation, fibre post space and cast post preparation in
carious premolar teeth.
 The percentage of preoperative hard tooth tissue volume lost
after caries removal was 8.3 +/- 5.83, after access cavity
preparation the loss of volume reached 12.7 +/- 6.7%
(increase of 4.4%). After root canal preparation, fibre post
space and cast post preparation the hard tissue volume lost
reached, 13.7 +/- 6.7 (increase of 1%), 15.1 +/- 6.3 (increase
of 1.4%) and 19.2 +/- 7.4 (increase of 4.1%) respectively
 Each procedure performed after caries removal significantly
increased the amount of hard tissue volume lost with the
exception of the root canal preparation
Ikram OH etal Micro-computed tomography of tooth tissue volume changes following
endodontic procedures and post space preparationInt Endod J. 2009 Dec;42(12):1071-6

4.  The survival relationship between the root
canal treated posterior teeth with and without
crown placement
 Coronal coverage with full cast crown reduced
the risk of tooth fracture
 Endodontically treated teeth with crowns had a
survival rate six times greater than that of teeth
without crowns

5.  1700s Fauchard inserted wooden dowels in
canals of teeth to aid in crown retention
 The wood would expand in the moist
environment to enhance retention of the dowel
 In 1869, Black favored the use of metal posts
in which a porcelain-faced crown was secured
by a screw passing into a gold-lined root canal.

6.  In mid-1800s, Clark developed a device which
was extremely practical for its time because it
included a tube that allowed drainage from the
apical area or the canal
 In 1878, Richmond crown was introduced it
incorporated a threaded tube in the canal with a
screw retained crown
 In 1958, Hampson EL etal and Demas NC et al;
modified to eliminate the threaded tube and was
redesigned as a 1-piece dowel and crown

7.  Endodontically treated teeth are weakened
due to decreased or altered tooth structure
attributed to:
◆ caries and/or previous restorations
◆ fracture or trauma
◆ endodontic access and instrumentation
◆ decreased moisture
The weakness is directly correlated to the
quantity of lost dentine.

8.  Microbial induced degradation or modification
of collagen can cause deterioration of strength
and toughness of dentin.
 Products used for root canal irrigation and
disinfection interact with mineral and organic
contents and significantly reduce dentin
modulus of elasticity & micro-hardness
 Disinfectants like eugenol and formocresol
increase the tensile strength of dentin via
protein coagulation chelation with
hydroxyapatite

9.  Randow and Glantz reported that teeth have a
protective feedback mechanism that is lost in
nonvital and root canal treated teeth,which also may
contribute to tooth fracture
 Sedgley and Messer tested the biomechanical
properties of dentin of endodontically treated teeth
and vital teeth of contralateral side and concluded
that endodontically treated teeth are not more brittle
 Sorensen, J.A. and J.T. Martinoff reported that
endodontically treated posterior teeth with intra-
coronal restorations show a high risk of unrestorable
cusp fracture. The use of crowns can significantly
improve the success for posterior teeth.

10.  Based on the material
Metallic
Non-metallic
 Based on method of fabrication
Pre-fabricated
Custom-fabricated
 Based on configuration
Tapered
Parallel
 Based on surface texture
Smooth sided
Threaded
Serrated

11. Wagnild et al (2002) summarized the ideal
physical properties of a post that include:
 Maximum protection of the root.
 Adequate retention within the root.
 Biocompatible / noncorrosive
 Maximum retention of the core and crown.
 Maximum protection of the crown margin
cement seal.
 Pleasing esthetics
 Radiopaque

12.  Amount of coronal tooth structure
 Tooth anatomy
 Position of the tooth in the arch
 Root length
 Root width
 Canal configuration
 Functional requirements of the tooth
 Torquing force
 Stresses

13.  Development of hydrostatic pressure
 Post design
 Post material
 Material compatibility
 Bonding capability
 Core retention
 Retrievability
 Esthetics
 Crown material

14.  Of paramount importance to the longevity of
the restored endodontically treated tooth is the
presence of adequate height (1.5-2 mm) of
sound tooth structure, or ferrule, between the
core and the crown margin
A tapered post without
a ferrule predisposes
the tooth to root
fracture, due to occlusal
forces being directed
internally down the
canal.
The post to
dislodgement,
due to occlusal
forces directed
down the canal
causing fatigue
failure of
cement.

15. Rosen in 1961 suggested that the “hugging action”
Eissman and Radke (1987) used the term ferrule effect to
describe this 360-degree ring of cast metal and
recommended extension of the definitive cast restoration at
least 2 mm apical to junction of the core and remaining tooth
structure.
The ferrule provides bracing or casing action to protect the
integrity of the root.

16. Wagnild et al (2002) emphasized that the crown and core
must meet five requirements for a crown preparation to be
successful:
(1) a minimum of 2 mm dentin axial wall height
(2) parallel axial walls
(3) the metal (core) must totally encircle the tooth
(4) it must be on solid tooth structure and
(5) it must not invade the attachment apparatus.

17.  Gegauff AG (1999) reported although the
crown-lengthening allows a ferrule, it also leads
to a much less favorable crown-to-root ratio
and therefore increased leverage on the root
during function
 adequate circumferential tooth structure for the
vital tooth can best be gained by
 surgical crown lengthening
 forced orthodontic eruption or
 sub-gingival preparation and prolonged
temporization to allow reestablishment of the
biological width

18.  Root anatomy such as root curvature, mesio-distal width,
and labio-lingual dimension dictates post selection
 ANTERIOR TEETH
◆ If no crown is required, a post is generally unnecessary.
◆ If a crown is necessary, a post is generally required.
 POSTERIOR TEETH (crowns generally required)
◆ Molar with an adequate pulp chamber don’t require a post.
◆ Molar with inadequate pulp chamber may require a post.
◆ Maxillary bicuspids generally require a post.
◆ Mandibular bicuspids require independent consideration.

19.  Goerig et al (1983) found that lateral excursive forces
can shear the remaining cusp or cause vertical root
fracture
 Greater emphasis on the adhesively retained core is
given to posterior teeth because of their close
approximation to the transverse hinge axis, muscle of
mastication and the morphological characteristics of
the tooth
 All endodontically treated maxillary premolars and
most mandibular second premolars should receive
cuspal coverage to protect the remaining cusps during
occlusion.

20.  The greater the post length, the better the
retention and stress distribution
 The length and shape of the remaining root
determines the length of the post
 The use of reinforced composite luting agents
may compensate for the reduced post length
 For molars with short roots the placement of more
than one post will provide additional retention for
the core foundation restoration

21.  Stern and Hirshfeld (1973) suggest
the post width should not be
greater than one third of the root
width at its narrowest dimension.
(Propotionist)
 Preservationist (Halle EB et al; 1984) proposed that the
post should be surrounded by a minimum of 1mm of sound
dentin.
 Pilo and Tamse (2000) advocated minimal canal
preparation and maintaining as much residual dentin as
possible (conservationist approach).

23.  Torsional forces on the post-core-crown unit
may lead to loosening and displacement of the
post from the canal
 resistance to torsional forces is integral to the
survival of the post-core-crown unit
 Active post designs provide greater torsional
resistance than a passive post

24.  Post and core restored endodontically treated
teeth are subjected to various types of
stresses: compression, tensile and shear
 an increase in the post length with the diameter
kept to a minimum will help to reduce shear
stresses and preserve tooth structure.

25.  Peters MT et al; 1983, and Fernandes AS et al;
2001 reported an increase in stress within the
root canal during cementation because of the
development of hydrostatic pressure
 The fitting stresses can be reduced by careful
placement of the post and by using a proper
post design with a cement vent to permit
escape of the luting agent
 The more viscous the cement, the greater the
development of the hydrostatic pressure

26.  The surface characteristics of the post also change
the retentive values
threaded > serrated surface >smooth surface
 if the available post space is short 5 to 6 mm, a
more retentive active post is indicated.
 If post space is 8 to 9 mm and the canal is not
funnel shaped, a tapered post may be a better
choice,

27.  The material used for the post should have
physical properties similar to that of dentin, can be
bonded to the tooth structure, and biocompatible in
the oral environment
 Posts with a high modulus of elasticity do not flex
with the tooth under loading and are empirically
believed to cause root fractures
 the modulus of elasticity for stainless steel and
Zirconia is roughly 20 times greater than dentin

28.  72% of longitudinal and oblique root fractures
to prolonged electrolytic reaction between
dissimilar post and core metals
 Corrosion of the post may be initiated because
of the access of the electrolyte to the post
surface, through microleakage around the
coronal restoration, and through the accessory
canals
Noble metals > titanium alloys > non metallic

29.  The bonding of a post to the tooth structure
should improve the prognosis by increasing
post retention and by reinforcing the tooth
structure
 resin luting agents showed good adhesion to
carbon fiber posts and glass fiber posts.
 The adhesion to Zirconia posts was found to be
unsatisfactory

30.  The primary reason for using a post is to retain
the core and the post head design is an
important factor
 It should provide adequate retention and
resistance to displacement of the core material.
 Bonding techniques are crucial to reinforce the
retention of the core to the post head

31.  Ideally the post system should be easy for the clinician
to retrieve the post without substantial loss of tooth
structure
 Post removal can be preformed by conventional rotary
instruments and solvents
 Other Post retrival intruments include the Masseran
Kit, Post Removal System, Endodontic extractors, and
ultrasonic unit Roto-Pro bur
 a combination of tube extractors with cyanoacrylate
will aid in post removal by breaking up the cement

32.  Freedman (2001) and Vichi (2000) have
emphasized the need to have the color of the
foundation restoration as close to that of natural
dentin
 This concern has led to the development of posts
made from reinforced resins or ceramics in an
effort to eliminate the color deficiency
 The availability of different cement shades permits
minor esthetic corrections under all ceramic
crowns

33.  good apical seal
 no sensitivity to pressure
 no exudate
 no fistula
 no apical sensitivity
 no active inflammation

34.  Optimal Post Preparation
◆ Use of non-end-cutting rotary instruments
◆ Minimal canal enlargement
◆ Diameter one-third root width or less
◆ Length at least equivalent to crown height
(short and extra long posts increase root fracture)

35. ◆ Minimum 4-5 mm gutta percha remaining
◆ Post modification to fit canal
◆ Passive post design and placement
◆ Adequate ferrule (1.5-2 mm) between core and
crown margins

37. Direct technique with autopolymerizing resin

38. Direct procedure using thermoplastic resin

39. Indirect procedure

45. o replaces missing coronal tooth structure
o combined with remaining coronal tissue, forms
shape of tooth preparation
o shaped in resin or wax
o cast directly onto the prefabricated post
o Can be made from plastic materials

46. o place rubber dam, remove GP till 4mm remains
o matrix band or copper band is placed
o condense amalgam into the root canal with
endodontic plugger

47. Direct procedure for single rooted
teeth
o prefabricated metal or custom
acrylic resin post
o resin added by bead technique
to post
o overbuild slightly and allow
polymerization
o carbide finishing and diamond
burs for shaping

50. Direct procedure for multi-rooted teeth
o fit prefabricated posts into the canal
o roughen the post to be incorporated
in core and lubricate the others
o build the core with autopolymerizing
resin
o remove the lubricated posts
o cast the core with the roughened
post

61. o post loosening – mean incidence 5%
o root fracture – 3%
o caries – 2%
o periodontal disease – 2%
Goodacre C.J et al, Clinical complications in fixed prosthodontics, J
Prosthet Denr 2003; 90: 31-41.

62. Restoration of the endodontically
treated teeth using exisiting coronal restoration

69.  Rosenstiel S.F, Land M.F, Fujimoto J, Contemporary
fixed prosthodontics, 3rd edition, 2001, Mosby, St.
Louis, pp 272-312.
 Shillingburg H.T, Hobo S, Whitsett L.D, Jacobi R,
Brackett S.E, Fundamentals of fixed prosthdontics, 3rd
edition, 1997, Quintessence, Canada, pp 194-209.
 Ingle J.I, Endodontics, 4th edition, pp 913-950.
 Morgano S.M, Brackett S.E, Foundation restorations in
fixed prosthodontics: Current knowledge and future
needs, J Prosthet Dent 1999; 82: 643-57.

70.  Cheung W, A review of the management of endodontically
treated teeth: Post, core and the final restoration, J Am Dent
Assoc 2005; 136: 611-619.
 Ikram OH etal Micro-computed tomography of tooth tissue
volume changes following endodontic procedures and post
space preparation Int Endod J.2009 Dec;42(12):1071-6
 Goldberg I.S et al, Restoration of endodontically treated teeth
:Review and Treatment recommendations, International
Journal od Dentistry 2009; 1-9.
 Fernandes A.S, Factors determining post selection: A
literature review, J ProsthetDent 2003; 90:556-6.
 Fages M, The Endocrown: A different type of all ceramic
reconstruction for molars, J Can Dent Assoc 2013;79:d140