13. What are the factors to be considered while planning the final restoration?
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16. 4 Based on the remaining tooth structure 4 Restoring endodontically treated teeth with posts and cores—a review Ingrid peroz et al.Quintessence International no.9 volume 36 oct 2005. Classification Description Class I 4 walls Class II 3 walls Class III 2 walls Class IV 1 wall Class V No wall
17. 6 Restoration of Endodontically Treated Teeth: An Evidence-Based Literature Review University of Toronto, Faculty of Dentistry. Int J Prosthodont 2008;18(1):40-1.
18. FERRARI AND OTHERS FOKKINGA & OTHERS SAMPLES 240 endodontically-treated premolars in 210 patients 307 endodontically-treated teeth in 257 patients TEST TREATMENT Fiber posts Cast post and core Pre-fab metal post and composite core CONTROL TREATMENT No post Post-free composite core DURATION (YRS) 2 Up to 17 CONCLUSIONS 4 coronal wall remaining: no difference in complication rates ≤ 3 coronal walls remaining: post placement increases survival rates Where “substantial remaining dentin” is available, a post and core does not perform better than a post-free core
19. 8 Ferrari M. Post placement affects survival of endodontically treated premolars. JDentRes 2007;86(8):729-734. 8 Fokkinga W. Up to 17-year controlled clinical study on post-and-cores and covering crowns. J Dent 2007;35(10):778-786.
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24. Anterior Teeth 13 Biomechanical considerations for the restoration of endodontically treated teeth: A systematic review of the literature. Didier Dietschi,, Ivo Krejci, Quintessence international Volume 39 number 2 february 2008
25. Anterior Teeth 14 Biomechanical considerations for the restoration of endodontically treated teeth: A systematic review of the literature. Didier Dietschi,, Ivo Krejci, Quintessence international Volume 39 number 2 february 2008
98. Anterior Tooth Class IV Class I - III Complete Coverage is required Prefabricated fiber post with composite core full ceramic crown Complete Coverage is not required Conservative Trt Resin composite Class V Complete Coverage is required
99. Posterior Tooth Class IV Class I-III Conservative Trt Onlay Class V Composite Core Fiber post Metal Ceramic Crown Pre-fabricated fiber post Composite Core Metal Ceramic crown
Studies pertaining to the clinical performance of post and core and non-post and core retained full coverage crowns. Our aim was to locate research, appraise and communicate the evidence found from scientific studies pertaining to the clinical performance of post and core and non-post and core retained full coverage crowns in order to determine which system would minimize post-operative complications and furnish long term prognoses.
Outcome Measures and Rates (1) Re-cementation of crown is not considered a failure (data is censured instead) (2) Extraction due to periodontal reasons is not considered a failure (data is censured instead). Includes tooth loss due to fracture of crown/root, periradicular disease, caries, trauma, or other reasons)
Typical configuration allowing conservative treatment of an endodontically treated tooth using an adhesive technique with a post as an additional retentive feature. ( a ) Preoperative view: the maxillary right central incisor is nonvital with a large composite restoration. ( b and c ) After removal of existing restorative materials, the residual tooth structure is judged insufficient (width and height) to assume full retention and strength as a prosthetic foundation.
( d and e ) A white fiber post is used as a retentive feature. ( f and g ) Completed prosthetic treatment with all-ceramic restoration on the right central and veneer on the left central incisor.
The inspection of the tooth’s hard tissue after removal of the filling showed a remaining palatal dentine wall so that a post insertion could be indicated. A rubber dam was applied in order to prevent further contamination of the endodont and to not impede the adhesive reconstruction of the crown through saliva penetration. The post bed was first rinsed with a 17% EDTA solution to remove the smear layer and then disinfected with a 5.25% NaOCl solution. After drying the well, the post( uxaPost is a glass fiber reinforced composite post) was seated and checked using a marker and foil pen. For the reconstruction of the coronal portion LuxaCore Z-Dual was used as well and lightcured as described above (figure 15).After the so-called ferrule preparation was completed (figure 16 and 17) a provisional was made and cemented in using a temporary adhesive.
The inspection of the tooth’s hard tissue after removal of the filling showed a remaining palatal dentine wall so that a post insertion could be indicated. A rubber dam was applied in order to prevent further contamination of the endodont and to not impede the adhesive reconstruction of the crown through saliva penetration. The post bed was first rinsed with a 17% EDTA solution to remove the smear layer and then disinfected with a 5.25% NaOCl solution. After drying the well, the post( uxaPost is a glass fiber reinforced composite post) was seated and checked using a marker and foil pen. For the reconstruction of the coronal portion LuxaCore Z-Dual was used as well and lightcured as described above (figure 15). After the so-called ferrule preparation was completed (figure 16 and 17) a provisional was made and cemented in using a temporary adhesive.
A 36-year-old patient came to the surgery complaining of pressure pain on tooth 16. The tooth had been provisionally restored while on holiday after the partial loss of a restoration in silver amalgam (Fig 1). The radiograph (Fig 2) showed a periapical transparency and it was decided that an endodontic intervention was needed on the tooth in question. It was decided that the inappropriate amalgam restoration on tooth 15 would be eliminated as well and two restorations would be applied in composite.
Fig 3 Once the tooth has been treated post-endodontically and after the cavity has been thoroughly cleaned, the healthy residual tissue can be assessed and decisions made on the most appropriate restoration technique. Fig 4 The composite restoration is built up very gradually in order to reduce curing shrinkage that causes stress to the walls.
Fig 5 The preparation is now complete and the retractor threads are positioned for a precision impression. Fig 6 The composite inlays are ready for adhesive cementing.
Fig 7 Once the first inlay has been cemented, any excess material is carefully eliminated. The inter-proximal can then be finished and the second inlay begun. Fig 8 The finished case. Please note the high level of functional and esthetic integration. Fig 9 The final radiographs show the healing and precision of the inlays: the different radio-transparencies of the materials utilized are clearly shown and this helps to understand the thickness of the buildup, the dentin, and the enamels used.
Hence, posts do not serve to strengthen teeth. They only serve to retain the core.In actuality, placing a post can predispose a tooth to fracture.
a post is that the minimum length of remaining solid tooth equal the sum of the biologic width (2.5 mm), the ferrule length (2 mm), the apical seal (4 mm) and the post length, or 8.5 mm + post length ( Fig. 1 ).
The post should be wide enough so that it does not deform under loading. This will depend on the alloy used for construction. A post should not be so wide that the root is unnecessarily weakened, since this increases the risk of root fracture
A serrated parallel-sided post is usually the optimal choice for an anterior root-filled tooth. Smooth-sided cast posts are used in canals that are oval in cross-section or when there has been significant loss of coronal dentine from the root canal. The surface of the cast post can be sandblasted to improve retention. Ceramic posts are smooth and are used with a dentine bonding agent to improve retention.
When a crown is placed on a tooth with optimal ferrule, the crown and root function as one integrated unit and occlusal forces are transmitted in normal physiological fashion to the periodontium. Where inadequate ferrule exists, occlusal stresses are transferred directly to the core and/or post with high likelihood of tooth, root or post fracture or post dislodgement. In such cases adequate circumferential tooth structure for the vital tooth can best be gained by a)surgical crown lengthening, b) forced orthodontic eruption or, in selected cases, c) sub-gingival preparation and prolonged temporization to allow reestablishment of the biological width.
Antirotation effect 1)Risk of fracture without ferrule 2)with ferrule
Posts can be broadly divided into prefabricated and custom made. The prefabricated posts can be further divided into metallic and non metallic.
Posts can be made from various materials such as stainless steel (A), aesthetic carbon fiber (B), carbon fiber (C), and ceramic (D)
Prefabricated post designs. A , Tapered, smooth. B , Parallel, serrated. C , Tapered, self-threading. D , Parallel, threaded. Note that the post fits into pretapped threads in the dentin. E , Parallel, serrated, tapered end.
DIRECT TECHNIQUE:(-pretend the model is patient ' s mouth-) Do NOT allow resin to set completely. Loosen and reset it several times while it is still rubbery • Once resin has polymerized, remove the pattern • Inspect for any undercuts in pattern and trim away • Measure and verify pattern post is same as prepared post length • Check that pattern goes in and out of canal without binding • Additional resin is Indirect Technique Any elastomeric material will make An accurate impression of the root canal if a wire reinforcement is placed to prevent distortion
Advantages: Preservation of maximum tooth structure, the post is fabricated to fit the radicular space Provision of anti-rotational properties Core retention, since core is an inherent part of the post RECOMMENDED USE: The cast post and core is indicated where the inclination of the canal is significantly different from the alignment of the crown. FIGURE: Cast gold post and core for replacement of an anterior tooth.
Recommended Use: Only when maximum retention is essential like in teeth with short roots.
Flexural Strength – the max load it can withstand during bending Tensile Strength - maximum load that a material can support without fracture when being stretched Elastic modulous – the deformity under elastic load, low value means that the matrial is flexible so it wont fracture easily
Core of the post and core restoration replaces carious, fractured or missing tooth structure It also retains the final crown
*Durability; dental crowns can last for up to 10 years if properly cared for *Aspect; the look of the tooth will be natural *Restoring dental function and protecting the tooth *Form; a destroyed tooth will get its initial shape after the placement of the crown
Inadequate tooth reduction can lead to a bulky crown and poor aesthetics. It is possible to finish the buccal margins with a porcelain butt shoulder to improve the marginal fit and give excellent appearance
Stained dentine and metal posts affect the aesthetic appearance of a porcelain jacket crown; however, they can be placed over cores built up in composite or glass ionomer. Excessive occlusal loading may be a problem and can result in unpredictable fracture. In-ceram crowns have a glass infiltrated aluminium oxide ceramic core covered with conventional porcelain. Greater tooth reduction is required than with a metal-ceramic crown (1.5-2.0 mm for In-ceram crowns).
Minimal Coronal damage *Intact Marginal Ridge, *Intact cingulum, *Intact incisal ridge, (esthetically acceptable) Moderate Coronal Damage *one or two small proximal lesions Significant Coronal damage *undermined marginal ridges, *loss of incisal edge, *coronal fracture, (esthetically unacceptable)
Minimal Coronal damage *low risk of fracture, *minimal occlusal forces, Intact buccal and lingual cusps Moderate Coronal Damage *minimum one sound cusp Significant Coronal damage little or no remaining coronal tooth structure, High risk of fracture
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