Fiber post

Fiber post in endodontically treated teeth: indications ,types , placement,bonding & removal

1. Fiber post Dr. Lena Ali Operative Dentistry Departmen t

2. Endodontically treated teeth Root canal treatment reduces the strength of the tooth but the amount of reduction is debatable ,but it for sure doesn’t strengthen the tooth

3. Endodontically treated teeth So endodontically treated teeth are more prone to fracture: The carious lesion destructive effect and leakage through pulp chamber The access cavity preparation through the pulp roof a major connector or bridge between the cusps that distributes the masticatory and functional forces over the entire tooth The change in arrangement and alignment of dentin collagen fibers Dentin dehydration (Debatable)

4. Types of posts Posts can be classified in a number of different ways : 1 ) Retention 2) Composition 3 ) Shape

5. Types of posts 1) Depending on how retention is achieved, posts can be divided into two main subgroups- Active posts Active posts derive their primary retention directly from the root dentine by the use of threads . Passive posts Passive posts gain retention as their name suggests by passively seating in close proximity to the post hole walls, and rely primarily on the luting cement for their retention .

6. Types of posts 2) Based on composition Metal (retentive or passive) (casted or prefabricated) Ceramics e.g. Cosmopost Fiber posts CARBON SILICA Silica Fibre Post : Aestheti Post,Aestheti Plus,Para Post,Snow Post Light Transmitting Post :Double Taper Light Post,Luscent Anchor Post ,Twin Luscent Anchor Post Ribbon Fibre Post : Ribbond

7. Types of posts

8. Types of Fiber posts 3) According to its general shape, each post can be divided into either -Tapered - Parallel sided -Serrated or smooth In general, active posts are more retentive than passive posts of a similar method of configuration, and parallel-sided posts are more retentive than tapered posts.

9. Ideal properties of post material Physical properties: like modulus of elasticity, compressive strength, flexural strength and thermal expansion, similar to that of dentin. It should esthetically resemble and bond efficiently to dentine . Aesthetic appearance and natural translucency

10. The introduction of fiber-reinforced composite posts helped to improve stress distribution, as their elastic modulus is similar to that of dentin usually leading to fewer and more favorable fracture pattern as demonstrated by several in vivo and in vitro studies

11. What is fiber post? *Fiber-based posts are essentially composite materials. *Fiber posts are manufactured from pre-stretched continuous fibers impregnated within a resin matrix with high degree of conversion and a highly cross-linked structure that binds the fibers. . The fibers could be of carbon, glass/silica, and quartz, whereas Epoxy and bis -GMA are the most widely used resin bases .

12. Types of fiber posts: Carbon fiber posts :are prepared from continuous and unidirectional carbon fibers in an epoxy resin matrix. “anisotropic behavior ” Carbon Fibre posts have been successfully used by dentists because of their strength and relative flexibility, ease of placement or ease of removal, if necessary, for endodontic retreatment. The black colour of carbon posts alter the aesthetic effect and hence they cannot be used in clinical situations in which subsequent non-metal and translucent crowns are planned.

13. Types of fiber posts: Silica fibers posts: Drawback of carbon-fiber posts to provide desired esthetics with all-ceramic restorations resulted in the production of translucent and tooth colored silica-fiber posts.It hold similar biomechanical properties as carbon- fiber posts with improved esthetics

14. 2.Silica fiber posts: Glass fiber posts :could contain different types of glass, such as E-glass (electrical glass), and S-glass (high-strength glass ). Quartz fiber posts :made from quartz fiber, which is pure silica in a crystallized form and provide better esthetic results.

15. 2.Silica fiber posts:

16. Polyethylene Fiber‑Reinforced Posts (PFR) They are polyethylene‑woven fiber ribbon of ultrahigh molecular weight ( Ribbond , Ribbond Inc., Seattle, WA ). They are not posts and cores in the traditional sense. This polyethylene‑woven fiber ribbon is coated with a dentine bonding agent and packed into the canal where it is then light polymerized in a position where it becomes rigid and acts like post.

17. Polyethylene Fiber‑Reinforced Posts (PFR)

18. Polyethylene Fiber‑Reinforced Posts (PFR) The leno weave or a triaxial architectural design imparts a three dimensional structure which composes of numerous nodal intersections that prevents propagation crack and also providing good retention for the composite cement.

19. Ribbond Inc. suggest that their woven polyethylene fibre can also be used to construct a directly placed composite post and core . Ribbond maintains the natural strength of the tooth and eliminates the possibility of root perforation. It conforms to the natural contours and undercuts of the canal and provides additional mechanical retention. There are no stress concentrations at the tooth-post interface. The Ribbond post and core is passive and highly retentive.

20. BONDABLE REINFORCEMENT FIBER POST (RIBBON FIBRE POST)

21. Shortcomes of fiber posts The predetermined shape of a prefabricated FRC post seldom follows the anatomy of the root canal. Therefore, when placing a prefabricated FRC post, a large space will be filled with resin cement coronally , and an unnecessary amount of dentin may have to be removed apically. The coronal part of the prefabricated FRC post-core system may not be stiff enough, to resist the high stresses produced by occlusal loads at the coronal and cervical areas ( Pegoretti et al. 2002 ). The result is a post-core system with insufficient load-bearing capacity and a restored tooth which will not be able to resist the high stresses cervically at the restoration margins. This will lead to marginal breakdown by means of adhesive failure on the tension side of the restoration and in the end secondary caries ( Schmitter et al. 2011). This problem arises particularly when the restoration is lacking a ferrule effect .

22. Shortcomes of fiber posts Prefabricated FRC posts are attached to the root canal dentin using adhesives and composite resin luting cements. However, their highly cross-linked polymer matrix with a high degree of conversion is nonreactive and therefore difficult to bond to resin luting cements and core materials ( Kallio et al. 2001 ). The bond between epoxy-based matrix of certain FRC posts and composite resin luting cements and composite core material is mainly mechanical ( Purton and Payne 1996 ; Torbjörner and Fransson 2004 ). To overcome the problem with adhesion, some manufacturers have added surface features, e.g., serrations (Love and Purton 1996 ; Al- Harbi and Nathanson 2003 ), to the prefabricated FRC post to increase mechanical retention of resin cements and core material. However, this has been shown to be non beneficial or even harmful with regard to adhesion and flexural strength of a FRC post with an anisotropic nature ( Soares et al. 2012 ; Zicari et al. 2013 ). Efforts with different surface treatments, of the prefabricated FRC post surface, both mechanical and chemical , have been made to improve the bond ( Mannocci et al. 1999a , b ; Lastumäki et al. 2002 ; Kallio et al. 2003 ; Sahafi et al. 2003 ). These methods include air-particle abrasion , silanization , and resin impregnation.

23. Frequent Myths Posts reinforce the residual tooth structure Post fit influences retention The coronal restoration has the greatest impact on the clinical success of the endodontically treated tooth A wider post space provides greater post retention because a thicker post can be used Translucent fiber posts transmit light to cure the cement in the root canal Notched fiber posts result in better retention than smooth fiber posts The type of root canal sealer affects bonding to root canal dentin A silane solution must be applied onto the post surface prior to luting Luting fiber posts in the root canal does not provide an adequate sealing because fiber posts may flex under occlusal load

24. Luting of FIBER POST Luting fiber posts with adhesive techniques involves the use of a dentin adhesive system for hybridization of the dentin substrate and a resin cement to fill in the space between the root canal walls and the fiber post. A.There are two adhesive strategies that can be used; Etch & rinse ( ER) adhesives, which require previous phosphoric acid etching and rinsing, Self etch (SE) adhesives .

25. B. The luting cement strategy Chemical cure Light cure Dual cure Typically, dual cure resin cements are the material of choice due to limited access of light to the middle and apical root thirds. In alternative to the ER and SE strategies, the luting protocol may be carried out without a separate adhesive system. In this case, self adhesive resin cements may be used.

26. Regardless of the type of material and/or technique, the bonding protocol to root dentin usually involves the same steps as used to bond to coronal dentin. However, an in vitro study with posts by Bouillaguet et al. ( Bouillaguet et al. 2003 ) reported that lower bond strengths were achieved when posts were bonded in the root canal system compared to when posts were bonded to flat ground radicular dentin. This difference is an example of several limiting factors that may require increased clinical awareness to minimize bonding failures.

27. Why bonding to the root canal is a challenging task? The Dentin Substrate

28. Why bonding to the root canal is a challenging task? The smear layer A.Primary smear layer

29. Primary Endodontic Smear Layer

30. B. Secondar smear layer

31. Why bonding to the root canal is a challenging task? Chemical Preparation During Endodontic Treatment Incompatibility Between Adhesives and Cements Insufficient Light Intensity During Polymerization Operator Experience Cavity Configuration (C-Factor)

32. Factors That Could Affect Fiber Post Bond Strength and Stability Cleanliness of the Post Space Preparation

33. Factors That Could Affect Fiber Post Bond Strength and Stability Selection of Sealers for Root Canal Filling

34. Factors That Could Affect Fiber Post Bond Strength and Stability Final Irrigation After Post Space Preparation

35. Step-by-step illustration of making an individually formed root canal post.(Polyethylene Ribbond )

36. Removal of fiber post

37. Removal of fiber post