Restorability of Root canal treated tooth

3. Treatment Planning Considerations for
Endodontically Treated Teeth

4. •The endodontic and restorative plans should be
considered jointly before treatment is carried out.
•The successful outcome of healing and function,
ultimately, depends upon maintaining the coronal
and apical seal of the endodontically treated tooth.
•The importance of coronal restoration after
endodontic treatment.

5. How Does the Coronal Restoration
Impact the Success of Endodontic
Treatment?

6. •It is generally accepted that a favourable outcome
of endodontic treatment relates to the technical
quality of the canal disinfection and long-term seal
of the obturating material.
•Although an adequate coronal seal may be
provided by a well-obturated root canal system,
over time an inadequate coronal restoration may
allow for the ingress of microbes and contribute to
the recontamination and ultimate failure of the
endodontic and restorative treatment.

7. Which is more important; an adequate
endodontic treatment or an adequate
coronal restoration? Could they be equally
important?

8. • Ray and Trope (1995) presented a thought-provoking finding,
in that the effect of the restoration on the radiographic success
was statistically greater than the effect of a good endodontic
filling.
• Tronstad et al. ( 2000 ) raised the counterpoint, stating that
the quality of the root canal filling was the most important
factor for the outcome of endodontic treatment.
• In a systematic review published by Gillen et al. ( 2011 ), the
impact of the quality of coronal restoration and the quality of
root canal fillings on success of root canal treatment were
considered. Poorer clinical outcomes may be expected
with adequate root filling-inadequate coronal restoration
and inadequate root filing-adequate coronal restoration.

9. Is there an expected rate of unfavourable
outcome associated With prosthodontic
failure?

10. • Vire(1991)evaluated and classified failures of endodontically
treated teeth according to
• Prosthodontic
• Periodontic
• Endodontic
• Teeth that had been crowned had a greater longevity (87
months) than uncrowned teeth (50 months) of the 116
endodontically treated teeth, of 59.4 % were prosthetic
failures, primarily due to crown fracture.

11. When and Why Do Endodontically
Treated Teeth Require Full
Coverage?

12. The need for a full-coverage restoration after
endodontic therapy is largely determined by:
• Tooth type
• Amount of tooth structure loss
• The amount of occlusal stress on the tooth.

13. Anterior Teeth
•Not always need complete coverage by placing a
complete crown
•Extensive loss of coronal tooth structure or tooth will
be serving as an FPD or RPD abutment crown or post
&crown

14. Posterior Teeth
•Subject to greater loading of cusps can be wedged
apart (Cuspal deflection)
•This type of Cuspal deflection creates stress within
the tooth and can lead to catastrophic coronal
fractures
•Complete coverage is recommended on teeth with
high risk of fracture

16. Quantifying Tooth Loss Peroz et al. ( 2005 ).
• Based on the number of remaining axial walls:
• Class I 4 walls present ( occlusal cavity )
• Class II mesio-occlusal (MO) or disto-occlusal (DO) cavity in
which one cavity wall is missing
• Class III MOD cavity with two remaining axial walls.
• Class IV category, a single axial wall either buccal or lingual
remains
• Class V crownless tooth with no remaining axial walls

20. • According to Peroz et al. ( 2005 ), if Class I, II, and III
cavity walls have thicknesses greater than 1.0 mm and
axial heights of at least 2.0 mm, then a post is not
recommended.
• When only one cavity wall remains in anterior teeth, it
is recommended to use fiber posts with all-ceramic
crowns; both metal and non-metal posts are acceptable
options for posterior teeth.

22. Tilk et al 1979 demonstrated that teeth with and without
posts had the same longevity outcome,
Raiden et al 1999 determined that teeth with posts
exhibited significantly more apical periodontitis than teeth
without posts.
Results from a study indicated that the preparation and
placement of a post can actually compromise the apical
endodontic seal.

23. Disadvantages to the Routine Use of a Cemented Post
•Placing the post requires an additional operative
procedure.
•Preparing a tooth to accommodate the post entails
removal of additional tooth structure.
•The post can complicate or preclude future
endodontic re-treatment that may be necessary.

24. Clinical Complications of Post and Core Restorations
• Post loosening
• Influence of post form
• Influence of post length
• Root fracture and Root perforation
• Influence of threaded posts
• Influence of post length
• Influence of residual dentin thickness
• Influence of instrument diameter

26. Principles for Restoration of
Endodontically Treated
Teeth

27. • Several factors affect the outcome when
endodontically treated teeth are restored.
➢ Post Length
➢ Post Diameter
➢ Canal Preparation
➢ Ferrule Effect
➢ Anatomical and Structural Limitations

28. Post Length
• The appropriate length for a post should be based on
its potential to minimize damage to the tooth,
optimize post retention, and maintain an appropriate
apical seal for the root canal filling.
• Recommendations have been made regarding post Length,
including the following:
1. Post length should equal the incisocervical or occlusocervical
dimension of the crown
2. Post should be longer than the crown
3. Post should be one and one-third times the crown length
4. Post should be one-half the root length

29. Several studies have demonstrated that short posts are
associated with higher root stresses and greater tendency
for root fracture to occur

30. Post Diameter
• Several studies have demonstrated that an increase in
post diameter does not increase post retention
• Increase in post diameter necessitates removal of
unnecessary tooth structure decreasing resistance to
fracture
• Deutsch et al determined that, when large diameter
posts (1.5 mm or more) were placed, root fracture
increased six fold for every millimetre of decreased root
diameter
• Increase in post diameter increases internal stresses
within the tooth

32. • post diameter not exceed one-third the root diameter
• To ensure that posts do not exceed one-third the root
diameter, the post diameter should be between 0.6 and
1.2 mm, depending on the tooth
• Preserve at least 1.0 mm of root wall thickness following
post preparation

33. Guidelines for pulp chamber preparation
• Prefabricated post ; morphologic undercuts present in
the pulp chamber should be retained for core retention
• Custom cast post and core; pulp chamber undercuts
should be blocked out with a definitive cement or
restorative material that is bonded to the tooth, or the
undercut should be eliminated by removal of tooth
structure

34. Guidelines for root canal preparation
• Successful use of rotary instruments is related to initial
use of a small-diameter instrument
• Confirm the amount of gutta-percha removed with a
radiograph and the use of a periodontal probe.
• After the length is established, any required increases to
the post diameter are accomplished incrementally with
larger rotary instruments or hand files.

35. Immediate versus delayed removal of gutta-percha and
post space preparation
• Several studies have indicated that there is no difference
in the leakage of the root canal filling material when the
post space is prepared immediately after completion of
endodontic therapy
• Abramovitz et al compared immediate gutta-percha
removal with hot pluggers and delayed gutta-percha
removal (after 2 weeks) with Gates Glidden drills. They
found no difference between the two methods.

36. Instruments for removal of gutta-percha without
disturbing the apical seal
• Three methods:
• Chemical (oil of eucalyptus, oil of turpentine, and
chloroform), not utilized for specific reasons (resulting
microleakage and inability to control removal)
• Thermal (electric or heated instruments)
• Mechanical rotary instruments

37. Ferrule Effect
• When possible, maintenance of 1.5 to 2.0 mm of intact
tooth structure around the entire circumference of a
core creates an optimally effective crown ferrule.
• If the supragingival crown preparation results in a
margin that is partially or entirely seated on foundation
restorative material, the forces of occlusion may be
transmitted to the foundation restoration and in the case
of a post and core, between the internal aspect of the
root and the post.

38. • A Ferrule Performs Three
Additional Functions
• 1. Protects the post against
fracture
• 2. Minimizes post dislodgement
• 3. Protects the cement seal at
the margin of the crown

40. • Gargiulo et al reported the average length of the
dentogingival junction to be 2.04 mm.
• They identified the subcomponents of the dentogingival
junction as the connective tissue attachment (1.07 mm) and
the epithelial attachment (0.97 mm).
• Ingber et al suggested that the term biologic width be used
to describe the average value of the dentogingival junction,
approximately 2 mm. They suggested that an additional 1
mm be added coronal to the 2-mm dentogingival junction as
an optimal distance between the bone crest and the
restorative margin

41. Components of the biologic width (~ 2.04 mm): EA epithelial attachment
(~ 1.00 mm); CTA connective tissue attachment (~ 1.00 mm). S sulcus (~
0.75 mm).

43. Management of Severely Damaged
Endodontically Treated Teeth

44. •Crown Lengthening
• Allowing longer clinical crowns and reestablishment of the
biologic width
• Crown lengthening surgery has been categorized as esthetic
or functional

45. Preprosthetic Orthodontic Tooth Eruption
These anatomical considerations exclude the
following situations from orthodontic tooth
eruption: posterior teeth where the furcation
would be exposed on tooth extrusion, and
teeth with moderate to severe bone loss from
periodontal disease where the procedure
would also compromise the optimal crown-root
ratio.

46. ■ Effect of apical preparation on crown-to-root ratio. A, Schematic of extensively damaged
premolar tooth. Apical extension of the gingival margin would encroach on the biologic width .This
preparation has no ferrule. C, crown length; R, root length. B, Creating a ferrule with orthodontic
extrusion reduces root length (R′), whereas crown length remains unchanged. C, Surgical crown
lengthening also reduces root length (R′) but increases crown length (C′). This results in a much
less favorable crown-to-root ratio, which may, in fact, weaken the restoration.

47. Supracrestal fiberotomy
Indicated when the bone is extruded with the tooth,
requiring its removal for two reasons: bone levelling with
the adjacent teeth and exposure of sufficient tooth
substance for crown restoration.
Fiberotomy. The surgical blade (blue) is inserted
to the depth of the gingival sulcus, through the
biologic width (BW), and severs all fibrous
attachments around the tooth, almost beyond the
supracrestal fibers (SF), to a depth of nearly 2 to 3
mm apical to the alveolar crest (dashed line).
(Adapted from Edwards7 with permission.)

48. Intra-alveolar Transplantation
a) Bone sounding of the root fragment.
b) Initial periapical radiograph.
c) Initial CBCT analysis of cross section
d) (d) Atraumatic extraction with a Power
tome.
(e) Arrested extraction.
(f) Interproximal interrupted sutures.
(g) Postoperative radiograph.
(h) Completed endodontic treatment at 5
weeks.
(i) Periapical radiograph at 13 weeks.
(j) Core build-up and tooth preparation.
(k) Anterior view of the tooth preparation.
(l) Occlusal view of the tooth preparation.

50. •Gingival margins do not stabilize completely
until at least 5 months after surgery
•In areas of no esthetic concern, it is this
author’s opinion that restorative treatment
can be commenced after at least a 6- to 8-
week healing period without aberrant healing
issues.

51. Root curvature
Anatomical and Structural Limitations
Molar posts should not exceed 7 mm in length in the
primary roots because of the potential for perforation
due to root curvature
Fig 4-17 Given the curvature of the
distal canal, the post space should not
exceed 7 mm from the orifice of the
canal. (Courtesy of Dr Axel Yabroudi,
Phoenix, AZ.)

52. Root selection for multirooted teeth

55. •a)Custom – made posts:
• type IV gold or Nickel-chromium alloys,
•b) Prefabricated posts:
• Metallic( stainless steel, titanium)
•Non-metallic (fiber reinforced resin, glass-
fiber, ceramic)

56. goldNiCr

61. •The luting agent must fill all dead space within the
root canal system
•A rotary (lentulo) paste filler or cement tube is used to
fill the canal with cement
•Inserted gently to reduce hydrostatic pressure Voids
may be a cause of periodontal inflammation via lateral
canals.

62. If cement is placed only on the post, as it is seated (large arrow) the air trapped within
the post preparation travels through the liquid cement (small arrows), producing
multiple voids. (Reprinted from Morgano and Brackett3 with permission.)

65. Core Build-up Materials

66. Amalgam
➢ It has physical properties that are better than those of most
other core materials
➢ Relatively dimensionally stable (even in the presence of water),
and is easy to condense
➢ Resistance to leakage of amalgam improves with time because
of its corrosion products
➢ It is a relatively inexpensive material compared with composite
resin or glass ionomer
Disadvantages
lack of bonding to dentin, the poor color under an all-ceramic
crown, and the formation of amalgam tattoo during tooth
preparation. At initial setting, the strength of amalgam is
low.Hence, it cannot be prepared right away
Advantages

68. Composite resin
Advantage
• Easy to use and satisfies esthetic demands
• More flexible than amalgam
• It adheres to tooth structure
• May be prepared and finished immediately
• Acceptable core material when substantial coronal
tooth structure remains

69. Disadvantage
• Poor choice when a significant amount of tooth structure is
missing
• Instability of the material in oral fluids (water sorption)
• Hygroscopic expansion of composite and cements can
generate significant stresses that have the potential to cause
extensive cracking in the overlying ceramic layer
• Shrinkage during polymerization causes stress on the
adhesive bond resulting in gap formation

70. Glass ionomer
• It adheres to tooth structure by forming a chemical bond
• Has a low thermal expansion coefficient
• Low polymerization shrinkage
• Has the ability to release fluoride
• Weakest core build up material when compared with
amalgam and composite resin.
• lack of adequate strength (flexural and tensile) along with
a sensitivity to moisture lower its resistance to fracture
• Used primarily to block minor undercuts in a tooth
preparation

72. Removal of Posts

73. Risks of Post Removal Procedures
•May cause cracks, vertical root fracture, or
perforation as a result of direct mechanical
action from the transfer of ultrasonic energy

74. Removal of Posts TECNIQUES
•Post removal devices divided into three different
categories:
• Mechanical post removal devices
• High-speed rotary instruments
•Ultrasonic devices.

75. Removal of Posts TECNIQUES
•Mechanical Devices:
• All mechanical post removal devices require some
degree of direct contact with the intraradicular post
and sufficient remaining tooth structure to provide
fulcrum to support the removal instrument.
• Most mechanical devices do have limited success in
removing threaded posts
• Threaded posts are best removed by grasping the
exposed and flattened head of the post and gently
turning it, usually in a counter clockwise direction

76. Endodontic Treatment of a Tooth with a Prosthetic Crown

77. Retrofitting a Post to an Existing Crown

82. References
Contemporary Fixed Prosthodontics; Fifth edition; Restoration of the
Endodontically Treated Tooth, 278
Restoration of Root Canal-Treated Teeth- An Adhesive Dentistry
Perspective, Jorge Perdigão , © Springer International Publishing Switzerland
2016
The Dental Reference Manual , A Daily Guide for Students and
Practitioners, Geraldine M. Weinstein Mitchell T. Zientz Editors© Springer
International Publishing Switzerland 2017
Contemporary Restoration of Endodontically Treated Teeth Evidence-Based
Diagnosis and Treatment Planning/[edited by] Nadim Z. Baba. © 2013
Quintessence Publishing Co Inc