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Crown PPT

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by

Dodz Dentoz

on 5 March 2013

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Transcript of Crown PPT

Zirconia Posts
Cementation Zirconia Posts are characterized by being having appropriate hardness which should be enough to offer good retention to the restoration , It is used mainly in anteriors being esthetically perfect. One factor that can improve the resistance to fracture of teeth needing restoration is adhesive cementation. Steps of Cementation through adhesion Post surface treatment through air abrasion with 30 µm aluminum oxide modified with silica, then rotating the post manually. Root canal dentin treatment: a multiple-bottle, total-etch adhesive system using 32% phosphoric acid for 30 secs. then rinse with water , after rinsing dry well using paper points then apply pre-Bond Resin . Mix The Adhesivve and apply it intra-radicular through lentulo no.40 spiral then light cure it Cementation of Ready made metal post B.Canal rinsed with water then dried by air A.The post space shoulde be cleaned by application of a chelating agent 17% EDTA for 30 seconds followed by rinsing with sodium hypochloride for 30 seconds D.Apply the cement with root canal tip or lentulospiral C. Canal dried with paper pointpoint till no debris come into paper point Final Positioned Post Cementation Of Cast Posts Composite Resin is the best for cast post however it is very technique-sensitive , also remnants of Zinc oxide Eugenol prevent full setting and polymerization of Resin Apply the cement onto the canal through lentulo spiral mainly, for Zinc Phosphate , we use solvent prior to the cement . Requirements of Cement . resist functional forces.
be insoluble in oral fluids
. be effective while maintaining a low film thickness
. exhibit anticariogenic properties
. be easy to manipulate and clean up
. must be radio-opaque in radiograph There are many types of ready made metal posts , as stainless steel , titatnium and gold plated , cementation may not be needed in some cases as it is done by screwing , but however it is preferred to undergo cementation for better retention For Zinc Phosphate , Only apply the mix over the post and the root canal after being dryed well with paper point and leave it for complete setting Cementation Of Fiber Posts Fiber Posts are considered one of the best types of posts , and considered a very advanced step for posts fabrication , being made mainly of composite resin , it could adhere easily to the core material made of composite , also for fiber cementation we could use Rely-X



Stabilize post by ligth curing coronal portion of post for 20 sec. oral set time is approximately 3.5 min……



Dispense equal amount of base & catalyst onto a mixing pad & mix for 20 sec, until a smooth & uniform paste results.working time at room temperature is at least 3 min.



Remove solvents with a vigorous blast of air for at least 15 sec, or until no visible movement of resin is noted.




Apply generous amounts with a clean brush onto the moist dentin surface.use a paper point to wet the deepest portions of the preparation,leave undisturbed for 15 seconds.



Dentin in the canal should be immediately and thoroughly dried until no visible moisture is visible on the paper point.


Apply the etchant to the post space and cavosurfaces for 10-15 seconds.
Rinse to remove etchant with a spray of oil free water for 5-10 seconds. Proceed immediately with composite core material build up..



Apply mixed cement to post & post space using root fillers or paper points,seat the post.



Mix equal number of drops of bonding agent &activator in a clean mixing well for 2 seconds. For complete removal of debris from the post space use a pesso brush premoistened with alcohol



Remove solvents with a vigorous blast of air for at least 15 sec, or until no visible movement of resin is noted.



Dispense equal amount of base & catalyst onto a mixing pad & mix for 20 sec, until a smooth & uniform paste results.working time at room temperature is at least 3 min. H2O2 should not be used for cleaning , after cleaning the root canal , it is not advised to use pumice or water , they affect the adhesive bond strength , triturate the Rely-X capsule for 10 secs , at 14,000 rpm Zinc Phosphate & Glass Ionomer are mostly used owing to be successful clinically and being easier to use than Composite Resin . Steps of cementation of different post types Components of the post crown system The core The post The extracoronal
restoration Classification of Posts According to the material According to method of construction: metallic
non metallic Luting cements Is a plastic paste of a fine powder
and liquid which hardens
to a solid mass.

Are used to retain restorations
and occupy marginal voids. Cementation should be a procedure
which allows full seating
of a crown with no damage
to the tooth or restoration. Adhesion to tooth structure.
Biological compatibility.
High mechanical properties.
Long working time.
Easy flow.
Translucency.
Easy removal of excess cement There are five major categories of dental cements for luting purposes, they are: Zinc phosphate Zinc polycarboxylate Zinc oxide and Eugenol (conventional, reinforced) Glass ionomer (conventional, resin modified) Composite resin (conventional, adhesive)
Mechanical interlocking
Irritant to the pulp
High mechanical prop.
Soluble cement
Long working time Adhesive.
Biocompatible.
Low compressive and modulus of elasticity.
Soluble
Extremely short working time
Difficult to remove excess cement Mechanical
biocompatible
Limited strength properties
soluble
short working time Adhesive (strong bond to non precious alloys)
Not irritant.
High compressive and tensile strength.
Resin modified resist solubility.
Longer working time.
Excellent flow.
Translucent. Proper selection of luting cements: The different cements should be properly selected
according to their merits for the particular
cementation utilization Cementation of post crown requires :- high flow
High strength properties
Adhesive So Cement of choice 1-Glass ionomer
2-Zinc phosphate
3-Adhesive composite resin
is used for cementation of non metallic posts such as
zirconium oxide ceramic
posts and carbon fiber
epoxy posts. Let's see different types of posts
& their cementation procedures 5. The remaining radicular tooth structure is etched thoroughly. It is then washed and dried. 4. The post is tried into the proper depth 2. The post is tried in and found too long 1. The post endodontic canal is ready for restoration Clinical Case 3. The size-associated reamer
is used to re-prepare the canal
to the proper length 6. The bonding agent is applied
into the canal and (inset) on
the remaining dentin as well 11. Once the core has been shaped to the required dimension it is light cured. 10.composite added to form the full dimensions of core 12.The post & core is now complete ( buccal view )

13.The post & core is now complete ( occlusal view ) 9. then light cured 8. The Post is inserted fully into the canal 7. injected into the canal from bottom to top 3-cement was injected into
the root canals
and then applied
over the posts. 2-the cement was introduced
into the root canals with
spiral filler and applied
over the posts. 1-The cement was applied over the posts only There are different techniques depending
on retention 4-cement was injected into the root canals
and a spiral was used to spread
it into the root canals,
and cement was also
applied over the posts. Panavia Rely X Ready made Custom made According
to post design Parallel sided
Tapered According
to post surface configurat ion
Smooth
Serrated
Threaded Custom Made
Posts Custom-made posts are usually fabricated
by a laboratory with the coronal portion (core)
attached Metallic :-
Ni-Cr
Co-Cr
Gold-plated
Titanum Non-Metallic :-
Zirconia

For many years, custom cast metal posts were considered the standard.
Although, they require more chair time than other posts and involve laboratory procedures and fees.
For these reasons, they are no longer widely used. the conventional custom-made cast metal posts prepared by direct wax pattern technique

The custom made post and core is then cemented in the root canal using glass ionomer luting cement Cementation Procedure

The post after being checked for fitness
within the root canal, is thoroughly cleaned
and washed then dried. Inspect all radicular preparation
surfaces for cleanliness.
The prepared root canal is gently
dried using paper points Apply the cement using the proper
technique for retention requirements.
To extend the working time, the cement
should be applied to a cool post Dry the root canal once again gently and push the post into place.
Final seating is best achieved until all
excess cement is seen to have escaped.
Remove the excess cement. This study compares the effect of different cementation techniques on the retention of cast posts and cores.

Under the conditions of this study,
the injection of cement into a root canal space followed by the use of a spiral resulted in the highest level of post retention. Ready made
Posts Supplied in different sizes & shapes
Available with special drills
Has simplicity of the technique
The recommended length is two-thirds the length of the root in bone while maintaining 5 mm of gutta-percha at the apex. Metallic :-
Ni-Cr
St-st
Titanum Non-Metallic :-
Carbon fiber
Glass fiber
Zirconia Metallic Ready Made The ready made metal post is then cemented
in the root canal using Zn Phosphate cement through an etch & rinse technique Non-Metallic Ready Made Carbon Fiber
Post Carbon fiber is very strong and almost unbreakable.
It is biocompatible, corrosion-resistant, and strong
Its elasticity is similar to dentin, enabling the carbon posts to move and work with the natural dentin.

The braided plait form of the carbon fiber bundles in a multi-axial arrangement give the posts superior resistance to bending and torsion forces compared to fibers in a typical single-axial arrangement Glass Fiber
Post Titanium metal prefabricated post Titanium alloys are generally weak and therefore not suitable for thin posts.
Titanium alloys have the same radiodensity as gutta-percha and are sometimes hard to detect radiographically. Zirconia
post Endo - Crown Used in Conservative approach
If there is sufficient tooth
structure & just small cavity
in middle of the tooth THANK YOU
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