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post and core techniques, materials and trouble shooting
- 2. Why?
- 4. Richard Feynman “If you want to Master something Teach it”
- 5. Restoration Of endo treated teeth Selection criteria Post & core Endo crown 1 32
- 6. why use post and core? o get retention and resistance from the root
- 7. 1 32
- 9. When to use post and core? When remaining coronal tooth Structure Can’t give us enough Retention or resistance
- 10. is post and core safe? Posts can cause vertical root fracture And other problems not properly planned and execu (Why not use it for every endo treated tooth?)
- 11. How can they cause VRF y transfer stress directly to the r Root is weaker and have less dentin thickness after RCT NOT MENTIONING 1.Additional dentin lost with dril 2.Rigid metal post 3.Inadequate post length 4.Threaded post…etc
- 13. conclusion Only use post when you need it Because it gives you both benefits and risks
- 14. So we decided to use post Lets do it right do it so that we can reduce risks failures
- 15. We will talk about : Length, design, materials,…etc
- 16. Post length 3 to 5 mm GP As long as possible At least longer than crown
- 17. Post length = Post is Like a lever Occlusalforces Forcestransmittedtotheroot throughthepost
- 18. In molars It doesn’t need to be longer than 7 mm And rest of the canals with core extentions
- 19. Choose the post According to canal size don't Enlarge a smaller canal To fit a larger post
- 20. Why should a post fit the canal? Why shouldn’t we allow space between post and canal?
- 21. parallel tapered Wedging effect Can be solved by providing Horizontal coronal surface Less retention They are the same if You use adhesive resin Cement(monoblock) Less conservative pically if you want it to fit coronally
- 22. serrated smooth More stress concentration at the apical end Equal stress Distribution All over the Length of the post
- 23. Best solution is paralleltapered With serrations
- 25. First of all Post receives bending force Translated to tensile on one s And compression on the other So we need to make the post from material that withstand tensile stress
- 26. What material? composite amalgam cement metal Fiber post NO YES BUT… YES BUT… NO NO
- 27. FIBER POSTS HAVE FIBERS fibers Resin matrix SEM
- 28. So if we used other materials with post In the canal in large amount They won’t withstand the tensile force They will fracture
- 29. Non rigid rigid metal Ceramic (zirconia) Carbon fiber Glass fiber Quartz fibe Fiber post If ferrule is 2 mm Or more If ferrule is Less than 2 mm
- 30. if post is flexible ? force crown post Absorbs some stress Bends slightly core and crown Will lean on cervical Part of the tooth(ferrule) Exerting force on it Finally rest of stress Goes to the canal throug The postNot all the stress will go to the root some will go to the ferrule and some absorbed by the post force F FStres s Some Stress here here
- 31. if post is flexible And no ferrule ? Stress will concentrate on the bond interface between core and tooth structure Causing debonding And Marginal gap
- 32. so If there is no ferrule we need rigid post to Transfer the entire stress to the root an d Take some precautions
- 33. Oval canals and canals with great taper Great space around post Needs custom post to fit it Post fits apically or does not fit Like cast post and core problem but It sacrifices dentin What if we need non rigid custom post That doesn’t sacrifice Dentin?
- 34. Canals likeWhich post can fit
- 35. Lets divide these canals into 2 types Space around The Post is less than half The diameter of the post . 25 mm . 25 mm 1.5 mm Space around The Post is more than half The diameter of The post or equal 1 mm 1 mm .25 mm 2 solutions 2 solutions • anatomic post • Oval post • Fiber augmented post • Accessory posts
- 36. But first You must select the post that most fits the canal even apically (master post) And surface treatment of post Should Select most suitable post using Xray
- 38. Anatomic post Why not fill the space with cement Cement is weak if applied in Large film thickness it will And post will come out of the Why not fill the space with Composite and cure it inside The canal Polymerization shrinkage will cause i debond from canal wall like it is a cl cavity filled with composite in on increment and post + composite wil come out 1. to apply composite on the post 2. Make it take canal’s shape 3. Cure it outside the canal 4. Then cement it as if it’s a cast post solution
- 39. 1 2 3 4
- 40. Accessory post
- 41. Fiber augmented post Same as accessory post technique but use fiber bundles(poly ethylene or glass fibers) ; ever stick c&b from GC
- 43. Surface treatment Canal side Fiber post side 1. Clean from sealer remnants by drill/gates 2. Use sponge with alcohol to clean walls 3. Advisable to use CHX 4. dry Self adhesive resin cement Don’t need etch & bond If core material is Used then 1. Etch 2. Bond with chemical/dual cure adhesive 1. Roughness by Sand blasting 24% H2O2 or 2. Then apply silane 3. Then apply bond/dry/cure
- 44. EXAMPLES
- 45. Dual cure core build up material Stropko’s irrigator Self adhesive resin cement capsule
- 47. Surface treatment Canal side metal post side 1. Roughness by or The same HF acid Sand blasting Co-jet Alloy primer(MDP)silane Bond That contain The primer/silane Or separate bottle You find them in
- 49. silaneMDP notes bisco kurary 3m Brochure states 21 Mpa shear bond strength without silane Doesn’t need Silane according To brochure
- 50. What to buy HF acid syringe 24% H2O2 Etch fiber And Metal post cement Prime fiber Metal post And bond to dentin
- 51. ال في المصادر Description بالفيديو الخاص