INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
www.indiandentalacademy.com
CONTENTS
• INTRODUCTION
• HISTORY
• CHANGES IN ENDODONTICALLY TREATED TEETH
• PRE-TREATMENT EVALUATION
• TREATMENT GOALS
•...
• FABRICATION OF POST
• PROVISIONAL RESTORATION
• INVESTING AND CASTING
• POST REMOVAL SYSTEM
• CONCLUSION
• BIBLIOGRAPHY
...
INTRODUCTION
• Initially only extraction
• From past 20 – 30 years, increased interest in restoring.
• It is well known th...
• From the time of Pierre Fauchard till date a wide range of
materials, techniques and designs have been described to
rest...
www.indiandentalacademy.com
HISTORY AND EVOLUTION
• Restoration of endodontically treated tooth by a post to retain a
crown dates back more than 250 y...
• Later wood replaced metal as the post material, and the “Pivot
Crown”, a wooden post fitted to an artificial crown and t...
• G.V. Black developed porcelain fused to metal crown held in by
a screw inserted into a canal filled with gold foil.
• In...
• During the 1930s, the custom cast post and core was developed
to replace the one piece post crowns, because of their dra...
Are endodontically
treated teeth different
www.indiandentalacademy.com
• Moisture loss
• Architectural changes
• Dentinal toughness
• Collagen alteration
• Altered esthetic characteristics
• Lo...
EVALUATION OF ENDODONTICALLY TREATED
TEETH
• ENDODONTIC EVALUATION
• PERIODONTAL EVALUATION
• RESTORATIVE EVALUATION
• EST...
ENDODONTIC EVALUATION
• Good apical seal as revealed by radiographs.
• No tenderness on percussion
• No apical sensitivity...
• Periodontal health is critical to the long term success of teeth that
have been endodontically treated and restored.
• P...
RESTORATIVE EVALUATION
Depends on,
• Amount of remaining tooth structure
• Tooth type
• Morphology
• Occlusal and prosthet...
www.indiandentalacademy.com
ESTHETIC EVALUATION
• Potential esthetic complication should be investigated before
initiation of endodontic therapy.
• Th...
• The translucency of All-ceramic crowns must be considered in
the selection of dowel and build-up materials.
• Tooth colo...
• Gutta percha discoloration can be visible in the coronal aspect
of an endodontically treated tooth and should be limited...
TREATMENT GOALS
• to maintain the coronal and apical seal of the root canal
filling material
• to protect and preserve rem...
www.indiandentalacademy.com
Post
The post is defined as a relatively rigid, metallic or non metallic restorative material
inserted into the root canal...
INDICATIONS FOR POST
• To retain the restoration
• To protect remaining tooth structure
• Marginal integrity
• To stabiliz...
CONTRAINDICATIONS FOR POST
• Abnormal root anatomy.
• Extensive caries including root caries.
• Perforations.
• External r...
Ideal requirements of post
• Simple and safe.
• Biocompatible.
• Should support the core and crown.
• Should provide resis...
Classification
Various classifications given by,
- Ingle and Bakland
- Shillinburg and Kessler
- Robbins
www.indiandentala...
depending upon the preparation
– custom made posts
– pre-fabricated posts
.
www.indiandentalacademy.com
depending upon the flexibility
– stiff
– flexible – flexi post
depending upon the esthetics
• esthetic
• non-esthetic
depe...
depending upon the design
a. tapered
- Smooth sided posts
- Serrated posts
- threaded posts
b. parallel
- Smooth sided
- S...
• Shillinburg and Kessler
• I. Custom-cast Posts
• II. Prefabricated posts
• a) Tapered, smooth-sided posts
• b) Tapered, ...
CLINICAL PROTOCOL FOR RESTORING
ENDODONTICALLY TREATED TEETH
• Anterior teeth
• Pulp less anterior teeth can also be conse...
• Anterior teeth that exhibit mesial and distal restoration should
be restored with a post and core prior to the placement...
Posterior teeth
• The need for a core or a post
and core is determined on
the basis of remaining tooth
structures as well ...
• Clinical consideration
• The apical seal, alveolar bone support, and root
morphology are all important considerations wh...
www.indiandentalacademy.com
• . In mandibular molars, the distal canal should be used
because of the root morphology and size of the canal.
• The bucc...
• When feasible, post placement should be carried out under the
aseptic conditions provided by rubber dam isolating the po...
• Post length
• The length of apical seal remaining after post preparation
and the degree to which it was disturbed during...
www.indiandentalacademy.com
• Traditional view of post length have advocated that the post be
 Equal to the height of the clinical crown.
 One and o...
• Post Width
• The size of a post is dependent on the root width and
canal morphology. In general, the width of a post sho...
• This point is especially critical in the apical area where the
root narrows and stresses are concentrated. Small diamete...
FACTORS AFFECTING RETENTION OF POST SYSTEMS
• Variables reported to affect retention include length, diameter
and design o...
. Post Length
• The post should equal the inciso-cervical or occluso-cervical
dimension of the crown.
• The post should be...
www.indiandentalacademy.com
www.indiandentalacademy.com
www.indiandentalacademy.com
• The length of the post has a significant effect on its retention
and in most instances, the more deeply the post is plac...
• posts with a length of at least 3- quarters of the length of the
root offered the greatest rigidity and least root defle...
Post Diameter
• Increasing the diameter of the post does not provide a
significant increase in the retention of the post, ...
• Therefore post diameter must be controlled to preserve
radicular dentin, reduce the potential for perforations, and
perm...
• . Post Design
• 6 basic commercial systems available as follows:
1. Tapered, smooth-sided posts.
2. Parallel-sided, serr...
Posts systems
• Tapered post, Non threaded
• A tapered post is less retentive than a parallel post.
Tapered posts generall...
• . For these reasons, this type of post is only recommended for
very tapered canals in which parallel sided posts would r...
Parallel sided posts, Threaded or Non threaded and inactive
 Parallel sided post design
offer increased retention
over ta...
advantages
 ease of placement,
 minimal stress production within the root,
 and good retention,
 as well as offering t...
• . Parallel sided posts, Threaded, Active.
• They rely on some form of mechanical engagement of
cutting flute into dentin...
• If a threaded post is selected for use, there must be an attempt
to minimize internal stresses from thread placement
• T...
Amalgam Coronal – Radicular Dowel Core
• It is not an absolute requirements that an endodontically
treated tooth should ha...
• Auxillary pins should be employed with this technique only if
additional retention is deemed absolutely necessary
www.in...
• Luting Agents
• Luting agents, including zinc phosphate, polycarboxylate,
glass ionomer, and filled and unfilled resin c...
• Glass ionomer, resin, and zinc phosphate cements all have
been shown to the acceptable for post placement.
• The cementa...
• . Any moisture remaining in the prepared canal will
significantly diminish retention of the post.
www.indiandentalacadem...
• Canal Shape
• Because the predominant canal shape is ovoid and the
walls of prefabricated posts are commonly parallel, t...
Preparation Of The Canal Space And Tooth
• When necessary, gutta percha should be removed with an
endodontic heat carrier ...
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• twist drills should not be used to remove filling materials.
Twist drills also should not be forced but should passively...
Location in the dental arch
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PREFABRICATED POSTS
www.indiandentalacademy.com
.
Carbon fiber reinforced epoxy resin posts
• Most prefabricated posts are metallic, but there are several
newer nonmetall...
• Carbon fiber reinforced epoxy resin is a recently introduced
dental restorative material composed of unidirectional carb...
• In vitro studies have indicated that these carbon fiber posts
possessed inferior strength compared to metal posts
• thei...
www.indiandentalacademy.com
Zirconia posts.
• With recent advances in ceramic technology, the all ceramic
crown has become more popular
• The response...
www.indiandentalacademy.com
• The post is made from fine grain, dense tetragonal zirconium
poly-crystals (TZP), and the zirconia post has been reporte...
Woven fiber composite materials
• The manufacturer of a cold glass plasma treated polyethylene
woven fiber has suggested t...
• These prefabricated posts
embedded in the woven
fiber composite were not as
strong as cast posts and
cores, but were les...
CORE MATERIALS
• When prefabricated posts are used, the core build up should be
either in amalgam, glass ionomer, or compo...
• Ideal properties of the core material
• High compressive and tensile strength.
• High modulus of elasticity (rigidity).
...
Composite resin
• Composite resin cores are commonly used in the anterior
region. The final strength of these cores ranges...
• . It is further seen that mechanical properties of composite
degrade with thermocycling and exposure of water.
www.india...
Amalgam
• The most commonly used core material with prefabricated
posts is amalgam. Amalgam is relatively easy to use, pro...
• Amalgam is classified as to the shape of its particles.
• Spherical
• Spheroidal, or
• A blending of the two types known...
• . Fast setting amalgam is necessary if the practitioner wants to
prepare for the final restoration at the same appointme...
Glass Ionomer
• Increased use of glass ionomer has been reported recently to
restore the endodontically treated teeth
• Th...
• Their use is indicated primarily for blocking out small
undercut areas for crown preparation
www.indiandentalacademy.com
Cast Post and Core
• Cast post and core can be fabricated by direct and indirect
methods.
• Customs post and core patterns...
• nickel chromium alloys offer an acceptable strength
component, they also exhibit low resilience to loading and
may under...
• Advantages of the cast post and core include
• Preservation of the maximum tooth structure as the post is
fabricated to ...
• Disadvantages include
• The appointments necessary to fabricate a pattern and then seat
the post.
• The decreased retent...
ROLE OF THE FERRULE EFFECT
• The ferrule has been defined as a circumferential band to cast
metal at the margin of a crown...
www.indiandentalacademy.com
• describe this 360-degree ring of cast restoration at least 2mm
apical to junction of the core and remaining tooth struct...
CORROSION
• Recommendation have been made that the post and core, and
possibly the crown, be fabricated of the same metal ...
CRITERIA FOR CAST POST AND CORE DESIGN
• maxillary incisors, requires locking notches or keyways
incorporated into the can...
www.indiandentalacademy.com
• The cast post is roughened prior to cementation with a
sandpaper disk to remove the oxide layer of the casting and
incre...
PROCEDURES
• three stage operation.
1. removal of the root canal filing material to the appropriate
depth.
2. enlargement ...
Removal of the endodontic filling material
• It is recommended that the root canal system first be
completely obturated an...
• There are two commonly used methods for removing gutta
percha –
1. with a warmed endodontic plugger
2. and with a rotary...
• calculate the appropriate length of the post.
• Select and endodontic condenser large enough to hold heat
• Mark it at t...
• shape the canal as needed
• This is accomplished with endodontic hand instruments or a
low speed drill.
www.indiandental...
Enlargement of the canal
• Prior to enlargement of the canal, a decision must be made
regarding the type of post system th...
For prefabricated posts
• Enlarge the canal one or two sizes with a drill, endodontic file,
or reamer that matches the con...
For custom made posts
Use custom made posts in canals that have a non-circular
cross section or extreme taper.
 Enlargin...
Procedures for custom made posts
I. 1- by direct method:
I. by self-cure resin
II. By thermo plastic material
• 2- by in-d...
By thermo plastic material
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laboratory method
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For multi rooted tooth
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Preparation of the coronal tooth structure
• Ignore any missing tooth structure
• Remove all under cuts that would prevent...
• This will create a positive stop to prevent overseating and
possible splitting of the tooth. Similarly rotation of the p...
Custom made posts
• A custom made post can be cast from a
• direct pattern or –with auto polymerising resin resin for sing...
• Direct procedure
• Indirect procedure
www.indiandentalacademy.com
Core fabrication
• The core of a post-and –core restoration replaces missing
coronal tooth structure, and thereby forms th...
Plastic filling materials
• The advantages of amalgam, glass ionomer or resins are that
• (1) maximum tooth structure can ...
Step-by-step procedure for amalgam
• Apply the rubber dam and remove gutta-percha-2to4mm
• Remove any existing restoration...
• Condense the first increments of amalgam into the root canals
with an endodontic plugger
• Carve the alloy to shape. The...
Direct pattern for multirooted teeth
• A direct pattern can be used for multirooted posterior teeth,
although limited acce...
• The core is cast directly onto the post of one canal.
• The procedure is simple, as long as smooth parallel sided or
tap...
6. Remove, invest, and cast the core with the roughened single
post.
7. When this has been done, the holes for the auxilia...
Indirect pattern for posterior teeth
• Wax the custom-made posts as described previously.
• Build part of the core around ...
INVESTING AND CASTING
• A cast post-and –core should fit somewhat loosely in the
canal. A tight fit may cause root fractur...
Review of litrature
• RETENSION STRENGTH OF 5 LUTING CEMENTS
ON PRE FABRICATED DOWELS AFTER ROOT
CANAL OBTURATION WITH ZOE...
• IN VITRO EVALUATION OF RETENTION OF
COMPOSITE FIBER AND STAINLESS STEEL
POSTS
• The stainless steel posts luted with zin...
• RETENTION OF CUSTOM CAST AND PARALLEL
SIDED SERRATED POSTS AS INFLUENCED BY
CEMENTING MEDIA
• When the mean retentive va...
SUMMARY AND CONCLUSION
• Although restoration of endodontically treated teeth has been
rationalized, information from cont...
References:
• Rosenstiel SF, Land MF,Fugimoto:Contemporary fixed
Prosthodontics,3rd edition,St louis ,2001 Mosby.
• Shilli...
• RETENSION STRENGTH OF 5 LUTING CEMENTS
ON PRE FABRICATED DOWELS AFTER ROOT
CANAL OBTURATION WITH ZOE SEALER mark
s. Hagg...
• RETENTION OF CUSTOM CAST AND PARALLEL
SIDED SERRATED POSTS AS INFLUENCED BY
CEMENTING MEDIA ajay v. sabane
www.indianden...
For more details please visit
www.indiandentalacademy.com
www.indiandentalacademy.com
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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.

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Restoration / academy general dentistry

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. CONTENTS • INTRODUCTION • HISTORY • CHANGES IN ENDODONTICALLY TREATED TEETH • PRE-TREATMENT EVALUATION • TREATMENT GOALS • POSTS/DOWEL AND ITS CLASSIFICATION • CORE www.indiandentalacademy.com
  3. 3. • FABRICATION OF POST • PROVISIONAL RESTORATION • INVESTING AND CASTING • POST REMOVAL SYSTEM • CONCLUSION • BIBLIOGRAPHY www.indiandentalacademy.com
  4. 4. INTRODUCTION • Initially only extraction • From past 20 – 30 years, increased interest in restoring. • It is well known that with proper endodontic treatment and adequate restoration, pulpless teeth can serve indefinitely as an integral part of the dental apparatus, provided the supporting structures are not compromised. www.indiandentalacademy.com
  5. 5. • From the time of Pierre Fauchard till date a wide range of materials, techniques and designs have been described to restore endodontically treated teeth. • However, there is no clear consensus regarding an ideal system, this is because each tooth presents with a unique requirement. • A thorough understanding of the proper use of posts and cores will enable clinicians of today to provide an optimum restoration that uniquely balances between maximizing retention of the tooth while minimizing the risk of failure. www.indiandentalacademy.com
  6. 6. www.indiandentalacademy.com
  7. 7. HISTORY AND EVOLUTION • Restoration of endodontically treated tooth by a post to retain a crown dates back more than 250 years. • In 1747, Pierre Fauchard a French dentist used “Tenons” which were metal posts (Gold or silver) into the roots of teeth to retain bridges. He used heat softened adhesive called MASTIC. www.indiandentalacademy.com
  8. 8. • Later wood replaced metal as the post material, and the “Pivot Crown”, a wooden post fitted to an artificial crown and to the root canal became popular. But they led to repeated episodes of swelling and pain. • In mid 1800 –Dr.F.H.Clark – developed a “spring loaded dowel” a retentive device consisting of a metal tube in the canal and a split metal dowel which was inserted into it. They also had channels for continuous suppuration from the underlying tissues. www.indiandentalacademy.com
  9. 9. • G.V. Black developed porcelain fused to metal crown held in by a screw inserted into a canal filled with gold foil. • In 1878 , the “Richmond Crown”, a single piece post-retained crown with a porcelain facing was engineered to function as a bridge retainer. www.indiandentalacademy.com
  10. 10. • During the 1930s, the custom cast post and core was developed to replace the one piece post crowns, because of their drawback of using in diverging roots and difficulty in removal and replacement of FPD crowns. • In 1960s prefabricated posts were introduced. • 1990 Duret et al described a non metallic material for the fabrication of posts based on carbon fibres reinforcement principle. www.indiandentalacademy.com
  11. 11. Are endodontically treated teeth different www.indiandentalacademy.com
  12. 12. • Moisture loss • Architectural changes • Dentinal toughness • Collagen alteration • Altered esthetic characteristics • Loss of Neuro-sensory feedback www.indiandentalacademy.com
  13. 13. EVALUATION OF ENDODONTICALLY TREATED TEETH • ENDODONTIC EVALUATION • PERIODONTAL EVALUATION • RESTORATIVE EVALUATION • ESTHETIC EVALUATION www.indiandentalacademy.com
  14. 14. ENDODONTIC EVALUATION • Good apical seal as revealed by radiographs. • No tenderness on percussion • No apical sensitivity • No exudate • No fistula • No active inflammation. www.indiandentalacademy.com
  15. 15. • Periodontal health is critical to the long term success of teeth that have been endodontically treated and restored. • Periodontal condition must be assessed before endodontic treatment, and the effect of planned restoration on the attachment apparatus must be considered. • Any structural defects of teeth should be considered that jeopardize coronal restoration. • Extensive caries, tooth fracture, previous restoration, perforation and external resorption can destroy tooth structure at the level of the periodontal attachment. PERIODONTAL EVALUATION www.indiandentalacademy.com
  16. 16. RESTORATIVE EVALUATION Depends on, • Amount of remaining tooth structure • Tooth type • Morphology • Occlusal and prosthetic forces • Periodontal support www.indiandentalacademy.com
  17. 17. www.indiandentalacademy.com
  18. 18. ESTHETIC EVALUATION • Potential esthetic complication should be investigated before initiation of endodontic therapy. • Thin gingiva may transmit a shadow of dark root through the tissue. • Metal or dark carbon fiber post and amalgam placed in the canal can result in unacceptable gingival discoloration from the underlying root. www.indiandentalacademy.com
  19. 19. • The translucency of All-ceramic crowns must be considered in the selection of dowel and build-up materials. • Tooth colored carbon fiber glass-reinforced composite resin, or zirconia posts can be used in esthetic areas. Similarly, tooth colored, rather than opaque, composite core material should be selected for esthetics. • An intact endodontically treated tooth requires critical control of endodontic materials in the coronal third of the canal and pulp chamber in order to maintain its color and translucency. www.indiandentalacademy.com
  20. 20. • Gutta percha discoloration can be visible in the coronal aspect of an endodontically treated tooth and should be limited to an apical level in the root. • Endodontic and restorative materials in these esthetically critical cases must be selected to provide the best health service with the minimum of esthetic compromise. www.indiandentalacademy.com
  21. 21. TREATMENT GOALS • to maintain the coronal and apical seal of the root canal filling material • to protect and preserve remaining tooth structure • to provide a supportive and retentive foundation for the placement of a definite restoration • To restore function and esthetics. www.indiandentalacademy.com
  22. 22. www.indiandentalacademy.com
  23. 23. Post The post is defined as a relatively rigid, metallic or non metallic restorative material inserted into the root canal of a nonvital tooth to aid in retention of a core component and to transmit the forces . www.indiandentalacademy.com
  24. 24. INDICATIONS FOR POST • To retain the restoration • To protect remaining tooth structure • Marginal integrity • To stabilize radicular fractures www.indiandentalacademy.com
  25. 25. CONTRAINDICATIONS FOR POST • Abnormal root anatomy. • Extensive caries including root caries. • Perforations. • External resorption. • Short roots. • Dilacerated roots. • Blunderbuss canal. • Young patients with coronal fracture, with incomplete root formation. • Patients with poor oral hygiene. www.indiandentalacademy.com
  26. 26. Ideal requirements of post • Simple and safe. • Biocompatible. • Should support the core and crown. • Should provide resistance for stresses. • Maximum protection of root. • Adequate retention within the root. • Pleasing esthetics, when indicated. • High radiographic visibility. • Easily removable. • Less expensive. www.indiandentalacademy.com
  27. 27. Classification Various classifications given by, - Ingle and Bakland - Shillinburg and Kessler - Robbins www.indiandentalacademy.com
  28. 28. depending upon the preparation – custom made posts – pre-fabricated posts . www.indiandentalacademy.com
  29. 29. depending upon the flexibility – stiff – flexible – flexi post depending upon the esthetics • esthetic • non-esthetic depending upon the retention  Active –eg; flexi-post, Kurer anchor • passive – cast post, smooth tapered post, parapost www.indiandentalacademy.com
  30. 30. depending upon the design a. tapered - Smooth sided posts - Serrated posts - threaded posts b. parallel - Smooth sided - Serrated posts - threaded post www.indiandentalacademy.com
  31. 31. • Shillinburg and Kessler • I. Custom-cast Posts • II. Prefabricated posts • a) Tapered, smooth-sided posts • b) Tapered, serrated posts • c) Tapered, threaded posts • d) Parallel, smooth-sided posts • e) Parallel, serrated posts • f) Parallel, threaded posts www.indiandentalacademy.com
  32. 32. CLINICAL PROTOCOL FOR RESTORING ENDODONTICALLY TREATED TEETH • Anterior teeth • Pulp less anterior teeth can also be conservatively restored with a bonded composite resin restoration rather than artificial crown. • A laminate veneer offers a conservative alternative if the facial surface is intact with moderate discolouration. . www.indiandentalacademy.com
  33. 33. • Anterior teeth that exhibit mesial and distal restoration should be restored with a post and core prior to the placement of a crown. • Mandibular incisors and maxillary lateral incisors would always require a post and core before placing an artificial crown. www.indiandentalacademy.com
  34. 34. Posterior teeth • The need for a core or a post and core is determined on the basis of remaining tooth structures as well as expected occlusal and prosthetic forces that will be applied www.indiandentalacademy.com
  35. 35. • Clinical consideration • The apical seal, alveolar bone support, and root morphology are all important considerations when determining post size and depth. Anatomy and morphology of teeth also should be considered when planning for a post • When posts are to be used in maxillary molars, the palatal canal should be used because of its relatively large and straight configuration www.indiandentalacademy.com
  36. 36. www.indiandentalacademy.com
  37. 37. • . In mandibular molars, the distal canal should be used because of the root morphology and size of the canal. • The buccal roots in maxillary molars and the mesial root of mandibular molars are not good candidates to receive a post because of their size, morphology and curvature www.indiandentalacademy.com
  38. 38. • When feasible, post placement should be carried out under the aseptic conditions provided by rubber dam isolating the post and prevents bacterial contamination of the radicular space by salivary leakage. www.indiandentalacademy.com
  39. 39. • Post length • The length of apical seal remaining after post preparation and the degree to which it was disturbed during post hole preparation can influence the long term success of the restoration. When ever mechanical preparation of the post hole is required, 4-5 mm of undisturbed apical gutta percha should remain after post preparation www.indiandentalacademy.com
  40. 40. www.indiandentalacademy.com
  41. 41. • Traditional view of post length have advocated that the post be  Equal to the height of the clinical crown.  One and one half times the length of the clinical crown and  Two third the length of the remaining root www.indiandentalacademy.com
  42. 42. • Post Width • The size of a post is dependent on the root width and canal morphology. In general, the width of a post should not be larger than one third of the root width at its narrowest dimension. In addition, the post should be surrounded by at least 1 mm of sound dentin www.indiandentalacademy.com
  43. 43. • This point is especially critical in the apical area where the root narrows and stresses are concentrated. Small diameter posts provide greater resistance to fracture as compared with larger diameter posts, and evidence exists indicating that the post diameter has no significance effect on retention. www.indiandentalacademy.com
  44. 44. FACTORS AFFECTING RETENTION OF POST SYSTEMS • Variables reported to affect retention include length, diameter and design of the post, canal shape and preparation, luting medium, method of cementation, and location in the dental arch. www.indiandentalacademy.com
  45. 45. . Post Length • The post should equal the inciso-cervical or occluso-cervical dimension of the crown. • The post should be larger than the crown. • The post should be 1/3rd the length of the crown. • The post should be a certain fraction of the length of the root such as one half, two thirds, or four fifths. • The post should end halfway between the crestal bone and the root apex. • The post should be as long as possible without disturbing the apical seal. www.indiandentalacademy.com
  46. 46. www.indiandentalacademy.com
  47. 47. www.indiandentalacademy.com
  48. 48. www.indiandentalacademy.com
  49. 49. • The length of the post has a significant effect on its retention and in most instances, the more deeply the post is placed, the more retentive it becomes www.indiandentalacademy.com
  50. 50. • posts with a length of at least 3- quarters of the length of the root offered the greatest rigidity and least root deflection (bending) when compared with posts that were a half or a quarter the root length. • Short posts are especially dangerous and have a much higher failure rate. www.indiandentalacademy.com
  51. 51. Post Diameter • Increasing the diameter of the post does not provide a significant increase in the retention of the post, however, it can increase the stiffness of the post at the expense of the remaining dentin and the fracture resistance of the root. www.indiandentalacademy.com
  52. 52. • Therefore post diameter must be controlled to preserve radicular dentin, reduce the potential for perforations, and permit the tooth to resist fracture www.indiandentalacademy.com
  53. 53. • . Post Design • 6 basic commercial systems available as follows: 1. Tapered, smooth-sided posts. 2. Parallel-sided, serrated, and vented posts. 3. Tapered, self-threaded posts. 4. Parallel-sided, threaded, split-shank posts. 5. Parallel-sided, threaded posts. 6. Carbon-fiber posts www.indiandentalacademy.com
  54. 54. Posts systems • Tapered post, Non threaded • A tapered post is less retentive than a parallel post. Tapered posts generally will have a wedging action on the root and have a relatively low retention rate. • These posts also have been shown to be less successful than placement of no post at all www.indiandentalacademy.com
  55. 55. • . For these reasons, this type of post is only recommended for very tapered canals in which parallel sided posts would require excessive tooth preparation. • www.indiandentalacademy.com
  56. 56. Parallel sided posts, Threaded or Non threaded and inactive  Parallel sided post design offer increased retention over tapered design.  These have excellent clinical retention and failures are caused most often by dislodgement. www.indiandentalacademy.com
  57. 57. advantages  ease of placement,  minimal stress production within the root,  and good retention,  as well as offering the added advantage of allowing final tooth preparation during the same appointment. www.indiandentalacademy.com
  58. 58. • . Parallel sided posts, Threaded, Active. • They rely on some form of mechanical engagement of cutting flute into dentin to gain increased retention. • These are the most controversial type of post category. • Posts in this group have been shown to induce increased stresses with in the root, which may later lead to root fracture. www.indiandentalacademy.com
  59. 59. • If a threaded post is selected for use, there must be an attempt to minimize internal stresses from thread placement • This category of posts is indicated only for very short root in which use of a nonthreaded post would result in failure due to lack of length for retention. www.indiandentalacademy.com
  60. 60. Amalgam Coronal – Radicular Dowel Core • It is not an absolute requirements that an endodontically treated tooth should have a dowel placed in the root. As already pointed out, this decision should be made after careful evaluation of the previously described criteria of remaining tooth structure, tooth type and morphlogy arch position, occlusal forces, and periodontal status www.indiandentalacademy.com
  61. 61. • Auxillary pins should be employed with this technique only if additional retention is deemed absolutely necessary www.indiandentalacademy.com
  62. 62. • Luting Agents • Luting agents, including zinc phosphate, polycarboxylate, glass ionomer, and filled and unfilled resin cements • The choice of dental cement for post cementation is essentially one of operator preference www.indiandentalacademy.com
  63. 63. • Glass ionomer, resin, and zinc phosphate cements all have been shown to the acceptable for post placement. • The cementation of custom cast or prefabricated dowel and core foundations must be carried out in an isolated environment to minimize entry of bacteria into the prepared canal and aid to moisture control. www.indiandentalacademy.com
  64. 64. • . Any moisture remaining in the prepared canal will significantly diminish retention of the post. www.indiandentalacademy.com
  65. 65. • Canal Shape • Because the predominant canal shape is ovoid and the walls of prefabricated posts are commonly parallel, the majority of luted prefabricated posts are unlikely to adapt well along their entire interface with the canal walls. • As a result, the post may not fit the preparation closely, and the luting agent may not totally fill the interface. www.indiandentalacademy.com
  66. 66. Preparation Of The Canal Space And Tooth • When necessary, gutta percha should be removed with an endodontic heat carrier until the desired length is reached. • A minimum of 4 to 5 mm of gutta percha must remain to preserve the apical seal. www.indiandentalacademy.com
  67. 67. www.indiandentalacademy.com
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  70. 70. • twist drills should not be used to remove filling materials. Twist drills also should not be forced but should passively follow the course of the previously established canal. Stops should be placed on engine-mounted drills at the desired depth as an added precaution. www.indiandentalacademy.com
  71. 71. Location in the dental arch www.indiandentalacademy.com
  72. 72. PREFABRICATED POSTS www.indiandentalacademy.com
  73. 73. . Carbon fiber reinforced epoxy resin posts • Most prefabricated posts are metallic, but there are several newer nonmetallic system available. • A post fabricated from a carbon fiber reinforced epoxy resin was developed in France by Duret and Renaud, and became commercially available in Sweden in 1992 www.indiandentalacademy.com
  74. 74. • Carbon fiber reinforced epoxy resin is a recently introduced dental restorative material composed of unidirectional carbon fibers that are 8 μm in diameter embedded in a resin matrix. The material is radiolucent and appears to be biocompatible www.indiandentalacademy.com
  75. 75. • In vitro studies have indicated that these carbon fiber posts possessed inferior strength compared to metal posts • their ability to bond to adhesive dental resins appears unremarkable, and their bond can be improved with mechanical retention such as serrations. www.indiandentalacademy.com
  76. 76. www.indiandentalacademy.com
  77. 77. Zirconia posts. • With recent advances in ceramic technology, the all ceramic crown has become more popular • The response to the need for a post that possesses optical properties compatible with an all ceramic crown, an all ceramic post has been developed. • This post is composed of zirconium oxide www.indiandentalacademy.com
  78. 78. www.indiandentalacademy.com
  79. 79. • The post is made from fine grain, dense tetragonal zirconium poly-crystals (TZP), and the zirconia post has been reported to possess high flexural strength and fracture toughness • zirconia post was designed for use with an adhesive resin cement. • Ceramics are tough materials with high compressive strengths, but are brittle when subjected to shearing forces www.indiandentalacademy.com
  80. 80. Woven fiber composite materials • The manufacturer of a cold glass plasma treated polyethylene woven fiber has suggested this material in a resin composite to provide corono-radicular stabilization for pulp less teeth. www.indiandentalacademy.com
  81. 81. • These prefabricated posts embedded in the woven fiber composite were not as strong as cast posts and cores, but were less likely to cause fracture of the roots when subjected to failure loads www.indiandentalacademy.com
  82. 82. CORE MATERIALS • When prefabricated posts are used, the core build up should be either in amalgam, glass ionomer, or composite resin www.indiandentalacademy.com
  83. 83. • Ideal properties of the core material • High compressive and tensile strength. • High modulus of elasticity (rigidity). • High fracture toughness. • Dimensional stability. • Ease of manipulation. • Short setting time. • The ability to bond to both tooth and post. • Biocompatibility. • Inert (no corrosion). • Natural tooth color, when indicated. • Low plastic deformation. • Low cost. www.indiandentalacademy.com
  84. 84. Composite resin • Composite resin cores are commonly used in the anterior region. The final strength of these cores ranges from good to excellent and they offer the option of preparation immediately after placement • They also lead to water sorption. Which results in core breakdown. This expansion of composites due to water is a potential concern due to generation of internal stresses. www.indiandentalacademy.com
  85. 85. • . It is further seen that mechanical properties of composite degrade with thermocycling and exposure of water. www.indiandentalacademy.com
  86. 86. Amalgam • The most commonly used core material with prefabricated posts is amalgam. Amalgam is relatively easy to use, provides a corrosion interface with the tooth, and has an excellent final strength. Its coefficient of thermal expansion is almost double of that of dentin and it is relatively stable in the presence of water. www.indiandentalacademy.com
  87. 87. • Amalgam is classified as to the shape of its particles. • Spherical • Spheroidal, or • A blending of the two types known as an admix www.indiandentalacademy.com
  88. 88. • . Fast setting amalgam is necessary if the practitioner wants to prepare for the final restoration at the same appointment, and the spherical alloys best meet this requirement. • This type of amalgam gains strength rapidly and will allow careful preparation after 15 to 20 minutes www.indiandentalacademy.com
  89. 89. Glass Ionomer • Increased use of glass ionomer has been reported recently to restore the endodontically treated teeth • The major drawback to their use is the question of adequate strength to support the final restoration. • They also require good isolation for placement. Which may present a clinical challenge. www.indiandentalacademy.com
  90. 90. • Their use is indicated primarily for blocking out small undercut areas for crown preparation www.indiandentalacademy.com
  91. 91. Cast Post and Core • Cast post and core can be fabricated by direct and indirect methods. • Customs post and core patterns should be casted in Type III and Type IV gold alloys or high noble alloys. • They possess adequate strength and minimize corrosion. • If a patient is not allergic to nickel, then nickel chromium alloys should be used www.indiandentalacademy.com
  92. 92. • nickel chromium alloys offer an acceptable strength component, they also exhibit low resilience to loading and may undergo corrosive change, making them less desirable as gold substitutes. • . It does not absorb water and has a coefficient of thermal expansion very close to that of dentin www.indiandentalacademy.com
  93. 93. • Advantages of the cast post and core include • Preservation of the maximum tooth structure as the post is fabricated to fit the radicular space. • Provision of anti-rotational properties and • Core retention, because the core is an inherent part of post and does not need to be retained by the post. www.indiandentalacademy.com
  94. 94. • Disadvantages include • The appointments necessary to fabricate a pattern and then seat the post. • The decreased retention of the tapering design, and • The wedging effect exerted on the root. www.indiandentalacademy.com
  95. 95. ROLE OF THE FERRULE EFFECT • The ferrule has been defined as a circumferential band to cast metal at the margin of a crown which is placed on solid tooth structure. • A post and core in a pulpless tooth can transfer occlusal forces intraradicularly with resultant predisposition to vertical fracture of the root. • “hugging action” of a subgingival collar of cast metal provided extracoronal bracing that could prevent fracture of tooth structure. www.indiandentalacademy.com
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  97. 97. • describe this 360-degree ring of cast restoration at least 2mm apical to junction of the core and remaining tooth structure. www.indiandentalacademy.com
  98. 98. CORROSION • Recommendation have been made that the post and core, and possibly the crown, be fabricated of the same metal as the prolonged electrolytic reaction between dissimilar post and core metals (stainless steel, silver, or brass posts reacting with the tin in the amalgam core) may result in longitudinal and oblique root fractures. • The products of this reaction, deposit in the root canal, induce volumetric changes and cause root fracture. www.indiandentalacademy.com
  99. 99. CRITERIA FOR CAST POST AND CORE DESIGN • maxillary incisors, requires locking notches or keyways incorporated into the canal to resist rotational movements. • The post should closely approximate the walls of the canals without a wedging effect • If the fit is too tight the forces of cementation may be sufficient to fracture the root. www.indiandentalacademy.com
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  101. 101. • The cast post is roughened prior to cementation with a sandpaper disk to remove the oxide layer of the casting and increase the retention. • The post is vented by flattening a small portion of the buccal or lingual post along the length allow cement to escape • www.indiandentalacademy.com
  102. 102. PROCEDURES • three stage operation. 1. removal of the root canal filing material to the appropriate depth. 2. enlargement of the canal and 3. Preparation of the coronal tooth structure. www.indiandentalacademy.com
  103. 103. Removal of the endodontic filling material • It is recommended that the root canal system first be completely obturated and then space made for a post. • This will ensure that lateral canals are sealed. www.indiandentalacademy.com
  104. 104. • There are two commonly used methods for removing gutta percha – 1. with a warmed endodontic plugger 2. and with a rotary instrument . Of these techniques, the warmed condenser is preferred because it eliminates the possibility of the rotary instrument’s inadvertently damaging the dentin. www.indiandentalacademy.com
  105. 105. • calculate the appropriate length of the post. • Select and endodontic condenser large enough to hold heat • Mark it at the appropriate length heat it, and place it in the canal to soften the gutta percha. • If the gutta percha is old and has lost its thermoplasticity, use a rotary instrument, • . Gates glidden drill. Para Post drill. www.indiandentalacademy.com
  106. 106. • shape the canal as needed • This is accomplished with endodontic hand instruments or a low speed drill. www.indiandentalacademy.com
  107. 107. Enlargement of the canal • Prior to enlargement of the canal, a decision must be made regarding the type of post system that will be used for fabrication of the post and core • Parallel sided prefabricated posts are recommended for conservatively prepared root canals in teeth with roots of circular cross section • Excessively flared canals we use custom made posts www.indiandentalacademy.com
  108. 108. For prefabricated posts • Enlarge the canal one or two sizes with a drill, endodontic file, or reamer that matches the configuration of the post. • In the case of a threaded post, the appropriate drill is followed by a tap. • Use a prefabricated post that matches standard endodontic instruments. www.indiandentalacademy.com
  109. 109. For custom made posts Use custom made posts in canals that have a non-circular cross section or extreme taper.  Enlarging canals to conform to a preformed post may lead to perforation.  Often very little preparation will be needed for a custom made post.  However, undercuts within the canal should be removed and some additional shaping usually is necessary. • Be most careful on molars to avoid root perforation www.indiandentalacademy.com
  110. 110. Procedures for custom made posts I. 1- by direct method: I. by self-cure resin II. By thermo plastic material • 2- by in-direct method: laboratory method www.indiandentalacademy.com
  111. 111. By thermo plastic material www.indiandentalacademy.com
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  114. 114. laboratory method www.indiandentalacademy.com
  115. 115. For multi rooted tooth www.indiandentalacademy.com
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  117. 117. Preparation of the coronal tooth structure • Ignore any missing tooth structure • Remove all under cuts that would prevent withdrawal of the pattern. • Remove any unsupported tooth structure, but be careful to preserve as much of the crown as possible. • Be sure also that part of the crown is prepared perpendicular to the post. www.indiandentalacademy.com
  118. 118. • This will create a positive stop to prevent overseating and possible splitting of the tooth. Similarly rotation of the post must be prevented by preparing a flat surface parallel to the post • Complete the preparation by eliminating sharp angles and establishing a smooth finish line. www.indiandentalacademy.com
  119. 119. Custom made posts • A custom made post can be cast from a • direct pattern or –with auto polymerising resin resin for single root canals • an indirect one. –for multi rooted tooth www.indiandentalacademy.com
  120. 120. • Direct procedure • Indirect procedure www.indiandentalacademy.com
  121. 121. Core fabrication • The core of a post-and –core restoration replaces missing coronal tooth structure, and thereby forms the shape of the tooth preparation • . It can be shaped in resin or wax and added to the post pattern before the assembly is cast in metal. www.indiandentalacademy.com
  122. 122. Plastic filling materials • The advantages of amalgam, glass ionomer or resins are that • (1) maximum tooth structure can be conserved because undercuts do not need to be removed, (2) treatment requires one less patient visit, • (3) there are fewer laboratory procedures, and • (4) testing generally shows good strength characteristics, possibly because of the good adaptation to tooth structure. www.indiandentalacademy.com
  123. 123. Step-by-step procedure for amalgam • Apply the rubber dam and remove gutta-percha-2to4mm • Remove any existing restoration, undermined enamel, or carious or weakened dentin • if cusps are missing-adequate retention can be gained by extending the amalgam into the root canals • floor of the pulp chamber is thin-protect it from condensing pressures with a cement base. www.indiandentalacademy.com
  124. 124. • Condense the first increments of amalgam into the root canals with an endodontic plugger • Carve the alloy to shape. The impression can be made immediately. www.indiandentalacademy.com
  125. 125. Direct pattern for multirooted teeth • A direct pattern can be used for multirooted posterior teeth, although limited access may make the indirect approach easier • . A single-piece core with auxiliary posts is used as opposed to the multisection core recommended for indirect posterior cast post-and cores www.indiandentalacademy.com
  126. 126. • The core is cast directly onto the post of one canal. • The procedure is simple, as long as smooth parallel sided or tapered posts are used 1. Fit prefabricated posts into the prepared canals. One post is roughened; the others are left smooth and lubricated. 2. Build up the core with auto polymerizing resin by the bead technique. 3. Shape the core to final form with carbide finishing burs. 4. Grip the smooth lubricated posts with forceps and remove them. www.indiandentalacademy.com
  127. 127. 6. Remove, invest, and cast the core with the roughened single post. 7. When this has been done, the holes for the auxiliary posts can be refined with the appropriate twist drill. 8. After verifying the fit at try –in, cement the core and auxiliary posts to place. www.indiandentalacademy.com
  128. 128. Indirect pattern for posterior teeth • Wax the custom-made posts as described previously. • Build part of the core around the first post. • Remove any undercuts. • Wax additional sections and cast them. • The use of dovetails to interlock the sections www.indiandentalacademy.com
  129. 129. INVESTING AND CASTING • A cast post-and –core should fit somewhat loosely in the canal. A tight fit may cause root fracture. The casting should be slightly undersized, which can be accomplished by restricting expansion of the investment (e.g., by omitting the usual ring liner or casting. www.indiandentalacademy.com
  130. 130. Review of litrature • RETENSION STRENGTH OF 5 LUTING CEMENTS ON PRE FABRICATED DOWELS AFTER ROOT CANAL OBTURATION WITH ZOE SEALER • Para posts cemented with panavia 21 and 4 different cements into dowel spaces prepared one week after obturation with guttaparcha/ or zoe sealer www.indiandentalacademy.com
  131. 131. • IN VITRO EVALUATION OF RETENTION OF COMPOSITE FIBER AND STAINLESS STEEL POSTS • The stainless steel posts luted with zinc posphate cement provided significantly greater tensile resistance than all composits fiber dowel group www.indiandentalacademy.com
  132. 132. • RETENTION OF CUSTOM CAST AND PARALLEL SIDED SERRATED POSTS AS INFLUENCED BY CEMENTING MEDIA • When the mean retentive values were compared between custom cast posts and parallel sided serrated posts the diff was stastically significant • The parallel sided serrated posts recorded significantly higher retentive values than custom cast posts www.indiandentalacademy.com
  133. 133. SUMMARY AND CONCLUSION • Although restoration of endodontically treated teeth has been rationalized, information from controlled long term clinical trials is still needed. • As much tooth structure must be preserved as possible and post and core is basically used to provide retention and support for a cast restoration. • There is not one post , core or final restoration that can be used in all – clinical situations. So we have to learn with these variables and understand the basic concepts of how to use them to maximum advantage www.indiandentalacademy.com
  134. 134. References: • Rosenstiel SF, Land MF,Fugimoto:Contemporary fixed Prosthodontics,3rd edition,St louis ,2001 Mosby. • Shillinburg HT, Hobo S, WhitSett LD, Jacobi R, Brackett SE: Fundamentals of fixed Prosthodontics, 3rd edition, Illinios Quintessence. • WFP Malone, DL Koth, E Cavazos Jr, Da Kaiser, SM Morgano: Tylman’s Thoery and practice of fixed Prosthodontics, 8th edition. Ishiyaku EuroAmerica, inc. publishers. Tokyo. St Louis. www.indiandentalacademy.com
  135. 135. • RETENSION STRENGTH OF 5 LUTING CEMENTS ON PRE FABRICATED DOWELS AFTER ROOT CANAL OBTURATION WITH ZOE SEALER mark s. Hagger etal jpd vol 11 no 3 2003 168-175 • IN VITRO EVALUATION OF RETENTION OF COMPOSITE FIBER AND STAINLESS STEEL POSTS john r.gallo atal jpd vol 1,1 no 1, 2002, 25-29 www.indiandentalacademy.com
  136. 136. • RETENTION OF CUSTOM CAST AND PARALLEL SIDED SERRATED POSTS AS INFLUENCED BY CEMENTING MEDIA ajay v. sabane www.indiandentalacademy.com
  137. 137. For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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