**Restoration of Endodontically Treated Teeth** Compiled and Edited by: Dr. Marrwa Ibrahim, BDS, MD.Sc Lecturer, UWA Dental School  Compiled and Edited by: Dr. Marrwa Ibrahim, BDS, MD.Sc Lecturer, UWA Dental School Comparative diagram illustrating three types of posts used in the restoration of endodontically treated teeth. The image is divided into three vertical panels labeled 'Preformed post', 'Esthetic post', and 'Cast post'. Each panel shows a cross-section of a tooth with the pulp chamber removed, an endodontic filling (gutta-percha), and a post inserted into the root canal. The preformed post appears metallic and threaded; the esthetic post is translucent or ceramic-colored; and the cast post is solid metal, custom-fitted to the canal shape. **The University of Western Australia** **Lecture 2: Post and Core Classification**  #### Post and Core Classification This lecture focuses on the classification systems and clinical considerations for post and core restorations in endodontically treated teeth. Clinical procedure image showing a dental model of the lower jaw with an extracted tooth. A golden post and core structure is being placed into the prepared root canal of the missing tooth using a metal instrument. The surrounding teeth are intact, and the pink gum tissue is visible. # Learning Outcomes By the end of this lecture, you should be able to: **Discuss** the evaluation of endodontically treated teeth before being restored **Discuss** the clinical indication of posts **Understand** the classification of post and cores **Discuss** different types of posts By the end of this lecture, you should be able to: - **Discuss** the evaluation of endodontically treated teeth before being restored - **Discuss** the clinical indication of posts - **Understand** the classification of post and cores - **Discuss** different types of posts # **Role of the Post – Updated View** **Evidence-based conclusions:** * **Posts do not reinforce ETT** * **Posts redistribute stress; depending on design they may increase stress in some regions** * **With adequate tooth structure and ferrule, survival differences with and without posts are small** The University of Western Australia Evidence-based conclusions: - Posts do not reinforce ETT - Posts redistribute stress; depending on design they may increase stress in some regions - With adequate tooth structure and ferrule, survival differences with and without posts are small # When Do We Place a Post? **Indications for a post:** * Inadequate coronal tooth structure to retain a core or crown by adhesion and macro-retention alone * Need for a core that will support a full coverage restoration or FPD retainer **Contraindications:** * Sufficient tooth structure for bonded/core retention * Short or curved roots where post would jeopardize integrity **Situations in between - need to assess:** * Occlusal load * Tooth position * Type of opposing tooth * Function: abutment of FPD or RPD   #### Indications for a Post - Inadequate coronal tooth structure to retain a core or crown by adhesion and macro-retention alone - Need for a core that will support a full coverage restoration or FPD retainer #### Contraindications - Sufficient tooth structure for bonded/core retention - Short or curved roots where post would jeopardize integrity #### Clinical Assessment Factors In borderline situations, the following must be assessed: - Occlusal load - Tooth position - Type of opposing tooth - Function: abutment of FPD or RPD Clinical intraoral photograph showing the occlusal view of a prepared molar tooth with a post space. The image demonstrates an inadequate coronal tooth structure with a visible pink core material inside the pulp chamber, illustrating the indication for placing a post due to insufficient retention. Clinical intraoral photograph showing a posterior tooth in the dental arch with significant decay or carious lesion on the occlusal surface and cervical area. This image likely illustrates a situation requiring assessment (e.g., occlusal load, tooth position) before deciding whether to place a post. Clinical Applications of Posts Typical scenarios: **A)** Post + Direct restoration (amalgam, composite) – separate **B)** Post + Core (amalgam, composite) for a crown preparation – separate **C)** Cast Post and Core (metal alloys such as gold) for a crown preparation – one-piece  Typical clinical scenarios include: 1. **Post + Direct restoration**: Amalgam or composite (separate components) 2. **Post + Core**: Amalgam or composite for a crown preparation (separate components) 3. **Cast Post and Core**: Metal alloys such as gold for a crown preparation (one-piece unit) Labelled diagram illustrating three clinical applications of dental posts (A, B, C). Panel A shows a molar tooth with a post and direct restoration (grey material). Panel B depicts a molar tooth with a post and core for crown preparation. Panel C illustrates a cast post and core as a one-piece unit. # Post Classification – Overview **Classify posts by:** * Fabrication method: prefabricated vs custom cast * Material: metal, fiber-reinforced composite, ceramic * Shape: parallel, tapered, anatomic * Surface: smooth, serrated, threaded Posts are classified based on the following criteria: - **Fabrication method**: Prefabricated vs. custom cast - **Material**: Metal, fiber-reinforced composite, ceramic - **Shape**: Parallel, tapered, anatomic - **Surface**: Smooth, serrated, threaded # Post Classification- Fabrication Method **THE UNIVERSITY OF WESTERN AUSTRALIA** ## Prefabricated vs Custom Posts ### Prefabricated posts: * Off-the-shelf, standardized dimensions * Best suited to relatively circular canals * Cemented in the root canal and the core is directly produced in composite or amalgam <img style="display:inline; width: 270px; padding-right: 25px; vertical-align: top;" src="https://i.imgur.com/2NNgP80.jpg"> <img style="display:inline; width: 300px; padding-left: 25px; vertical-align: top;" src="https://i.imgur.com/i5GypYo.jpg">    - Off-the-shelf, standardized dimensions - Best suited to relatively circular canals - Cemented in the root canal and the core is directly produced in composite or amalgam A labeled figure showing a collection of prefabricated dental posts arranged horizontally. The image includes metal threaded posts and white fiber-reinforced or zirconia posts of varying shapes (tapered and parallel-sided), visually demonstrating the 'off-the-shelf, standardized dimensions' mentioned in the OCR text. An intraoral clinical photograph showing a prepared tooth with a dark-colored prefabricated post cemented inside the root canal. A metal matrix band is visible on the adjacent tooth, indicating preparation for a restoration. This visual demonstrates the placement step where the core is directly produced. A close-up clinical photograph of anterior teeth with a temporary restoration placed over a root-end post. The post extends through the temporary material to the gingival margin, illustrating the clinical application and appearance of a prefabricated post system. **Post Classification- Fabrication Method** **Prefabricated vs Custom Posts** **Custom cast posts and cores:** Indicated in flared or irregular canals Allow ideal fit and core shape but require more appointments The post and the core are cast as a single unit    - Indicated in flared or irregular canals - Allow ideal fit and core shape but require more appointments - The post and the core are cast as a single unit Collage of clinical procedure images demonstrating custom cast post fabrication. The top-left panel shows an X-ray radiograph of a tooth with a radiopaque post and core in place. Adjacent panels show the preparation of orange wax patterns on dental models using a tool and a red measuring ruler. The central image displays a red wax pattern for a post on a textured blue mat. Bottom panels show the finished metal post and core assembly placed on a model, alongside a close-up of a hand holding the completed prosthesis. Close-up photograph of a custom cast metal post and core specimen against a light blue background. The object is silver-colored with a distinct irregular shape, featuring a thin post extending downwards and a wider, flared crown section. Close-up photograph of another custom cast metal post and core specimen, likely made of gold or similar alloy, resting on a white surface. This specimen has a long, tapered post section and a thickened crown portion with visible casting details. # Post Classification- **Shape** **Parallel** • Increased retention (parallel walls) • Produce uniform stress distribution along the post length • Less root fracture • Stress concentration at the apical portion **Tapered** • Follow natural canal form and configuration preservation of tooth structure at the post apex • Wedging effect – more stress • Stress concentration at the coronal portion of root • Lower retentive strength   #### Parallel Posts - Increased retention due to parallel walls - Produce uniform stress distribution along the post length - Less root fracture - Stress concentration at the apical portion #### Tapered Posts - Follow natural canal form and configuration - Preservation of tooth structure at the post apex - Wedging effect creates more stress - Stress concentration at the coronal portion of root - Lower retentive strength Clinical photograph showing a row of six dental posts with parallel walls. The visual demonstrates the 'Parallel' post classification mentioned in the text, which is associated with increased retention and uniform stress distribution. Clinical photograph displaying three groups of tapered dental posts. This visual illustrates the 'Tapered' post classification described in the text, which follows natural canal form but results in lower retentive strength due to the wedging effect. # Post Classification-Surface Features ## **Active Post:** * Engage the walls of the canal (**Threaded**) * More retentive * Introduce more stress into the root * Require substantial amount of root dentin * Indication: short roots in which maximum retention is needed (**limited use**) ## **Passive Post:** * Smooth, serrated * Retained strictly by the luting agent * Require close adaptation to the canal wall * Less stress into the root * Less catastrophic failures * More commonly used <br> <img>Comparison of Active Post (threaded) and Passive Posts (smooth/conical and serrated)  #### Active Posts - Engage the walls of the canal (Threaded) - More retentive - Introduce more stress into the root - Require substantial amount of root dentin - Indication: Limited use for short roots where maximum retention is needed #### Passive Posts - Smooth or serrated surface - Retained strictly by the luting agent - Require close adaptation to the canal wall - Less stress introduced into the root - Less catastrophic failures - More commonly used Clinical photograph showing a side-by-side comparison of four dental posts. From left to right: an active post with a threaded surface (metallic), a passive post with a textured/serrated surface (metallic), and two conical smooth posts (white ceramic). The image visually demonstrates the 'Surface Features' described in the text, contrasting the threaded design of the Active Post with the smooth or serrated designs of Passive Posts. # Post Classification-Material ## Ideal Physical Properties of Post Materials **Dentin-like stiffness** (modulus of elasticity close to dentin) to promote favourable stress distribution **Reliable bondability** to tooth structure (strong adhesion to dentin and core materials) **Biocompatible** and corrosion-resistant in the oral environment **Energy-dissipating behaviour** (helps absorb/attenuate functional forces rather than concentrate stress) - **Dentin-like stiffness**: Modulus of elasticity close to dentin to promote favourable stress distribution - **Reliable bondability**: Strong adhesion to dentin and core materials - **Biocompatible**: Corrosion-resistant in the oral environment - **Energy-dissipating behaviour**: Helps absorb or attenuate functional forces rather than concentrate stress **Post Classification- Fabrication Method /Material** **Pre-fabricated posts** •**Metal**: stainless **steel**, titanium (± titanium alloys) •**Fibre-reinforced composite (FRC)**: glass fibre, quartz fibre, carbon fibre •**Ceramic**: zirconia **Custom / cast posts (post–core)** •**Cast metal alloys**: • Noble / high-noble (e.g., gold-based) • Base-metal (non-precious) alloys •**Custom ceramic**: zirconia (CAD/CAM or laboratory-fabricated)   #### Pre-fabricated Posts - **Metal**: Stainless steel, titanium (and titanium alloys) - **Fibre-reinforced composite (FRC)**: Glass fibre, quartz fibre, carbon fibre - **Ceramic**: Zirconia #### Custom / Cast Posts (Post–Core) - **Cast metal alloys**: - Noble / high-noble (e.g., gold-based) - Base-metal (non-precious) alloys - **Custom ceramic**: Zirconia (CAD/CAM or laboratory-fabricated) Clinical photo showing a collection of pre-fabricated dental posts arranged on a green background. The image demonstrates the variety in shape and surface texture of these components, corresponding to the 'Pre-fabricated posts' category mentioned in the OCR text. Clinical photo displaying custom / cast posts (post–core). The image shows four distinct examples: three resin-based or acrylic posts (left) and two metal alloy posts (right), illustrating the materials listed under 'Custom / cast posts'. **Metal Posts – Advantages and Risks** **Metal Posts (Cast or Pre-fabricated)** **Advantages** **Long clinical track record with predictable performance** **High strength and stiffness → low risk of post fracture** **Good retention** when properly designed and fitted Some studies report **higher retention for stainless-steel posts** compared with certain fibre posts (e.g., carbon fibre) (Schwartz et al., 2004; Peutzfeldt et al., 2008; Figueiredo et al., 2015) **Risks / Limitations** **High modulus of elasticity** may concentrate stress in root dentin → increased risk of root fracture **Corrosion** possible with some alloys (rarely clinically significant, but may contribute to degradation) **Aesthetic limitations** under translucent ceramic crowns **Cast post–core**: increased chairside/lab time and cost, and more complex retreatment/removal  #### Advantages - Long clinical track record with predictable performance - High strength and stiffness resulting in low risk of post fracture - Good retention when properly designed and fitted - Higher retention reported for stainless-steel posts compared with certain fibre posts (e.g., carbon fibre) #### Risks and Limitations - **High modulus of elasticity**: May concentrate stress in root dentin, increasing risk of root fracture - **Corrosion**: Possible with some alloys (rarely clinically significant, but may contribute to degradation) - **Aesthetics**: Limitations under translucent ceramic crowns - **Cast post–core**: Increased chairside/lab time, higher cost, and more complex retreatment or removal Clinical photograph of five pre-fabricated metal posts. The image displays the physical objects corresponding to the 'Metal Posts' topic discussed in the text, illustrating their metallic appearance and varying tip geometries. # **Fiber Posts – Evidence and Limitations** **Advantages:** * Modulus closer to dentin → more favorable, repairable failure patterns * Esthetically compatible under all-ceramic crowns * Corrosion resistance * Biocompatible **Limitations:** * Technique-sensitive bonding to radicular dentin * Failure of cementation (adhesion to dentin is not reliable)  #### Advantages - Modulus closer to dentin, leading to more favorable and repairable failure patterns - Esthetically compatible under all-ceramic crowns - Corrosion resistance - Biocompatible #### Limitations - Technique-sensitive bonding to radicular dentin - Failure of cementation (adhesion to dentin is not always reliable) Clinical photograph showing four fiber posts arranged diagonally. The posts are translucent white with colored identification bands (blue, yellow, red, and black) near the top, likely corresponding to different brands or types of fiber-reinforced composite materials. # Ceramic and Zirconia Posts * **Excellent aesthetics** — ideal under translucent all-ceramic crowns * **High stiffness and brittleness** — may concentrate stress and increase risk of root fracture * **Retreatment is challenging** — difficult to remove if endodontic re-intervention is needed * **Less robust clinical evidence** compared with fibre and metal posts  - **Excellent aesthetics**: Ideal under translucent all-ceramic crowns - **High stiffness and brittleness**: May concentrate stress and increase risk of root fracture - **Challenging retreatment**: Difficult to remove if endodontic re-intervention is needed - **Clinical evidence**: Less robust clinical evidence compared with fibre and metal posts Clinical photograph of a white ceramic or zirconia dental post against a black background. The object is shaped like an arrow with a wider head and narrower tail, likely designed for insertion into a tooth root canal to support a crown. [^1]: Original PDF page 1: [[L2_RETT_2026_Post and core classification.pdf#page=1|L2 RETT 2026 Post and core classification, p.1]] [^2]: Original PDF page 2: [[L2_RETT_2026_Post and core classification.pdf#page=2|L2 RETT 2026 Post and core classification, p.2]] [^3]: Original PDF page 3: [[L2_RETT_2026_Post and core classification.pdf#page=3|L2 RETT 2026 Post and core classification, p.3]] [^4]: Original PDF page 4: [[L2_RETT_2026_Post and core classification.pdf#page=4|L2 RETT 2026 Post and core classification, p.4]] [^5]: Original PDF page 5: [[L2_RETT_2026_Post and core classification.pdf#page=5|L2 RETT 2026 Post and core classification, p.5]] [^6]: Original PDF page 6: [[L2_RETT_2026_Post and core classification.pdf#page=6|L2 RETT 2026 Post and core classification, p.6]] [^7]: Original PDF page 7: [[L2_RETT_2026_Post and core classification.pdf#page=7|L2 RETT 2026 Post and core classification, p.7]] [^8]: Original PDF page 8: [[L2_RETT_2026_Post and core classification.pdf#page=8|L2 RETT 2026 Post and core classification, p.8]] [^9]: Original PDF page 9: [[L2_RETT_2026_Post and core classification.pdf#page=9|L2 RETT 2026 Post and core classification, p.9]] [^10]: Original PDF page 10: [[L2_RETT_2026_Post and core classification.pdf#page=10|L2 RETT 2026 Post and core classification, p.10]] [^11]: Original PDF page 11: [[L2_RETT_2026_Post and core classification.pdf#page=11|L2 RETT 2026 Post and core classification, p.11]] [^12]: Original PDF page 12: [[L2_RETT_2026_Post and core classification.pdf#page=12|L2 RETT 2026 Post and core classification, p.12]] [^13]: Original PDF page 13: [[L2_RETT_2026_Post and core classification.pdf#page=13|L2 RETT 2026 Post and core classification, p.13]] [^14]: Original PDF page 14: [[L2_RETT_2026_Post and core classification.pdf#page=14|L2 RETT 2026 Post and core classification, p.14]] [^15]: Original PDF page 15: [[L2_RETT_2026_Post and core classification.pdf#page=15|L2 RETT 2026 Post and core classification, p.15]] [^16]: Original PDF page 16: [[L2_RETT_2026_Post and core classification.pdf#page=16|L2 RETT 2026 Post and core classification, p.16]]