Restoration of Endodontically Treated Teeth Preformed post Esthetic post Cast post  #### Common Post Types - Preformed post - Esthetic post - Cast post Comparative diagram showing three types of posts used for restoring endodontically treated teeth: Preformed post (metal threaded), Esthetic post (fiber-reinforced translucent), and Cast post (solid metal). Each panel illustrates the post placement within a tooth root surrounded by periodontal structures. 0 THE UNIVERSITY OF WESTERN AUSTRALIA Lecture 3: Post and Core Fabrication Techniques The University of Western Australia  Lecture 3: Post and Core Fabrication Techniques Composite figure illustrating post and core fabrication techniques. The collage includes: (left) two radiographs showing a tooth root canal with an endodontic post inserted; (center) a red wax or resin post on a blue textured mat, and close-ups of tools shaping orange wax blocks with blue tips; (right) multiple views of wax posts being manipulated with dental instruments. These images collectively demonstrate clinical steps in fabricating and adapting posts for restorative dentistry. # **Learning Outcomes** By the end of this lecture, you should be able to: * Understand the difference between direct, indirect and direct indirect post fabrication techniques * Describe each technique available to fabricate a post and core * Understand the advantage and disadvantage of each technique • Describe the post space preparation * Describe the coronal preparation of a tooth receiving a post By the end of this lecture, you should be able to: - Understand the difference between direct, indirect, and direct-indirect post fabrication techniques - Describe each technique available to fabricate a post and core - Understand the advantage and disadvantage of each technique - Describe the post space preparation - Describe the coronal preparation of a tooth receiving a post The University of Western Australia Oral Health Centre of Western Australia **FABRICATION TECHNIQUE** 3 Techniques: - Direct – **pre-fabricated** post + core (composite or amalgam) - Indirect – impression technique - Direct-indirect – burnout resin technique Cast post and core ↓ TEMPORARY POST-CROWN   #### Primary Fabrication Methods There are three main techniques for the fabrication of posts and cores: - **Direct Technique**: Utilizes a pre-fabricated post combined with a core made of composite or amalgam. - **Indirect Technique**: Utilizes an impression-based workflow. - **Direct-Indirect Technique**: Utilizes a burnout resin technique. Following the fabrication of a cast post and core, a temporary post-crown is required. Red curly brace visually grouping three text items: 'Indirect – impression technique', 'Direct-indirect – burnout resin technique', and the end of the first line 'pre-fabricated post + core'. The brace points to the label 'Cast post and core', indicating these methods are used to create cast posts. Yellow downward arrow pointing from 'Cast post and core' to 'TEMPORARY POST-CROWN', illustrating a procedural sequence or relationship between the two concepts. ```mermaid graph TD A[POST SPACE PREPARATION] --> B[Direct Technique] A --> C[Impression Technique] A --> D[Burn-out Resin Technique] B --> B1[Select Pre-fabricated post] B1 --> B2[Check if antirotational features are needed] B2 --> B3[Cement Post] B3 --> B4[Core build up] B4 --> B5[Crown preparation] B5 --> E[Temporary crown] C --> C1["Select impression post<br>(plastic and smooth surface)"] C1 --> C2[Impression using the impression post] C2 --> C3["Pour-up"] C2 -- "Temp Post-Crown" --> C6 C3 --> C4[Burn-out post and core] C4 --> C5[Cast the post and core] C5 --> C6[Cast post and core cementation] C5 -- "Temp Post-Crown" --> E C6 --> C7[Refinement of crown preparation] C7 --> E D --> D1["Select burn out post<br>(plastic and serrated surface)"] D1 --> D2["Separator (canal and coronal surface)"] D2 --> D3["Copy the shape of the canal using Duralay resin (bead-brush technique)"] D3 --> D4["Core build-up using Duralay resin (bead-brush technique)"] D4 --> D5["Core build-up using Duralay resin (bead-brush technique)"] D5 --> D6["Crown preparation on the Burn-out post and core (rough prep)"] D6 --> C5 ``` Preparation of coronal structure: * Removal of existing restorations * Eliminate undesirable undercuts (cast post and core only) * Crown preparation to create ferrule   #### Procedural Workflows Following post space preparation, the workflow depends on the chosen technique: **Direct Technique** 1. Select a pre-fabricated post. 2. Determine if anti-rotational features are required. 3. Cement the post. 4. Perform core build-up. 5. Complete crown preparation. 6. Place temporary crown. **Impression (Indirect) Technique** 1. Select a plastic, smooth-surfaced impression post. 2. Take an impression using the impression post. 3. Pour up the model. 4. Create the burnout post and core. 5. Cast the post and core. 6. Cement the cast post and core. 7. Refine the crown preparation. 8. Place temporary crown. **Burn-out Resin (Direct-Indirect) Technique** 1. Select a plastic, serrated-surface burnout post. 2. Apply separator to the canal and coronal surfaces. 3. Copy the shape of the canal using Duralay resin (bead-brush technique). 4. Perform core build-up using Duralay resin (bead-brush technique). 5. Perform rough crown preparation on the burnout post and core. 6. Proceed to casting and cementation. #### Preparation of Coronal Structure - Removal of existing restorations. - Elimination of undesirable undercuts (required for cast post and core only). - Crown preparation to create a ferrule. Flowchart diagram illustrating 'POST SPACE PREPARATION' with three main branches: 'Direct Technique', 'Impression Technique', and 'Burn-out Resin Technique'. Each branch contains a sequence of procedural steps (e.g., 'Select Pre-fabricated post', 'Pour-up', 'Copy the shape of the canal using Duralay resin'). Arrows indicate workflow progression, including cross-references like 'Temp Post-Crown' pointing to shared steps. All text is contained within colored boxes. Text list titled 'Preparation of coronal structure:' containing three bullet points: 'Removal of existing restorations', 'Eliminate undesirable undercuts (cast post and core only)', and 'Crown preparation to create ferrule'. POST SPACE PREPARATION **1. Determine the post length based on PA** - Increase of post length = increase of retention - **Careful**: Very long may damage the seal of the root canal fill or cause root perforation if the apical third is curved or tapered **Preserve tooth structure** A side view diagram of a root with short posts labeled 'R' and 'R'. Text indicates: **"Short posts are more likely to result in root fracture."** A pink force vector 'F' is shown near the root tip. B side view diagram of a root with long posts labeled 'R'' and 'R''. Pink arrows are on the posts. A pink force vector 'F' is shown near the root tip. Bottom right corner text: Contemporary Fixed Prosthodontics 4<sup>th</sup> ed    #### Preservation of Tooth Structure - Increase of post length results in an increase of retention. - **Caution**: Excessively long posts may damage the seal of the root canal fill or cause root perforation if the apical third is curved or tapered. - Short posts are more likely to result in root fracture. #### Length Determination via Periapical Radiograph (PA) 1. Determine the post length based on PA. Side view diagram of a tooth root labeled 'A' with a short post. Pink arrows labeled 'R' point to the root structure near the gum line. A pink force vector labeled 'F' points upwards at the bottom tip. A text box states: 'Short posts are more likely to result in root fracture.' Side view diagram of a tooth root labeled 'B' showing a long post extending deeper into the canal compared to diagram A. Pink arrows labeled 'R'' point to the root structure. A pink force vector labeled 'F' is shown at the bottom. Illustration of a tooth with a post and crown. Red arrows indicate specific areas of concern or structural failure points on the tooth anatomy. ```html <table border='1'> <tr> <td>R</td> </tr> <tr> <td>4-5 mm</td> </tr> <tr> <td>R</td> </tr> <tr> <td>F</td> </tr> </table> POST SPACE PREPARATION 1. **Determine the post length based on PA** * **Increase of post length = increase of retention** * **Careful:** Very long may damage the seal of the root canal fill or risk root perforation if the apical third is curved or tapered * **Ideal:** at least 5-mm apical seal * **Very short roots and high crowns:** 4-mm apical seal ```  #### Apical Seal Requirements - **Ideal**: Maintain at least a 5-mm apical seal. - **Very short roots and high crowns**: Maintain a 4-mm apical seal. - **Caution**: Excessively long posts may damage the seal of the root canal fill or risk root perforation if the apical third is curved or tapered. Labelled cross-sectional diagram of a tooth illustrating post space preparation. Shows the root canal filled with gutta-percha (labeled 'F' for filling material), and a post inserted into the prepared space. The region labeled 'R' indicates the apical seal area, which is annotated as 4-5 mm in height, consistent with the text's recommendation for ideal apical seal length. The University of Western Australia Oral Health Centre of Western Australia POST SPACE PREPARATION 1. Determine the post length based on PA • There is no absolute guideline for the optimal post length - Post length at least equal to the crown length - 2/3 of the remaining tooth length - ½ of the clinical root - ¾ of the of the root canal length Always maintain the 4-5 apical seal Schwartz et al 2004   #### Guidelines for Optimal Post Length There is no absolute guideline for optimal post length, but common benchmarks include: - Post length at least equal to the crown length. - 2/3 of the remaining tooth length. - 1/2 of the clinical root. - 3/4 of the root canal length. **Note**: Always maintain a 4-5 mm apical seal. Clinical radiograph (X-ray) of posterior teeth showing post space preparation. The central tooth displays a prepared root canal with a purple-colored core and post structure at the base. Labels include 'Clinical crown', 'Clinical root', 'Post', and 'Core'. Brackets labeled 'a' indicate proportional measurements relative to crown and root lengths. Schematic diagram illustrating ideal post length proportions. Left side shows a cross-section of a prepared tooth with annotations for '2/3' and '1/3' of remaining tooth length. Right side illustrates root anatomy with '1/2' clinical root height and '1/2' root canal length marked. A blue arrow indicates apical seal maintenance zone. Work length (WL) Removal of GP Extract text from PDF. Use the OCR text for context to enhance accuracy. Prioritize image text but use the OCR text to resolve ambiguities. If the text is in a different color format it as bold. Errors may occur in the OCR text; if is corrupted or error-ridden then ignore it. <table> <tr> <th> <h3>POST SPACE PREPARATION</h3> </th> </tr> <tr> <td> **1. Determine the post length based on PA** <br><br> **1°)** Measure the crown height (use contralateral tooth as a reference) <br> **2°)** Mark where the post should end (apical end) <br> **3°)** Pick one point on the tooth that is visible in the X-ray (e.g., incisal edge, marginal ridge, cusp tip) <br> **4°)** Measure the distance between the reference point and the apical limit = working length <br> <br> Removal of GP </td> </tr> </table>  #### Measurement Steps for Working Length 1. **Measure the crown height**: Use the contralateral tooth as a reference. 2. **Mark the apical end**: Identify where the post should terminate. 3. **Select a reference point**: Pick a visible point on the tooth in the X-ray (e.g., incisal edge, marginal ridge, cusp tip). 4. **Calculate distance**: Measure the distance between the reference point and the apical limit to determine the working length (WL). Radiograph diagram illustrating post space preparation. The image shows a tooth with an X-ray overlay highlighting the working length (WL) measurement between the incisal edge and the apical limit, marked by red arrows labeled 'X'. A yellow bracket indicates the crown height reference point. **The University of Western Australia** Oral Health Centre of Western Australia **POST SPACE PREPARATION** **2. Rubber Dam** - Avoid bacterial contamination (saliva, blood) - Avoid inhalation of instruments (endo files, burs) - Avoid contact of sodium hypochlorite with mucosa (we have to clean the canal at the end of the session) #### Rubber Dam Usage - Avoid bacterial contamination from saliva or blood. - Prevent inhalation or ingestion of instruments (e.g., endodontic files, burs). - Protect mucosa from contact with sodium hypochlorite used during canal cleaning. **3. Removal of GP** - Start with a heated endodontic plugger - Use a rubber stop to mark the **WL** - Use Gate Glidden bur to reach the **WL** **3D Caulking Instrument** **3D Caulking Instrument** **3D Caulking Instrument** **3D Caulking Instrument** **3D Caulking Instrument** **3D Caulking Instrument** **AVOID PERFORATION** - Use the bur parallel to the path of insertion - Light vertical forces - Start with smaller bur and increase the size if necessary - Should see red GP coming out (not white dentin) - Take PA if you are not sure if the bur is following the root canal **Contemporary Fixed Prosthodontics 4ed**      #### Procedure for Gutta Percha Removal - Start with a heated endodontic plugger. - Use a rubber stop to mark the working length (WL). - Use a Gates Glidden bur to reach the WL. #### Perforation Prevention - Use the bur parallel to the path of insertion. - Apply light vertical forces. - Start with a smaller bur and increase size if necessary. - Monitor debris: Red gutta percha should be visible rather than white dentin. - Take a periapical radiograph (PA) if the bur's path is uncertain. Intraoral radiograph showing a tooth with an endodontic post and filling. A yellow bracket highlights the prepared post space, labeled 'Y', indicating the measurement or depth of the post cavity preparation. Close-up clinical photo of a heated endodontic plugger being used to remove gutta-percha (GP) from a root canal. The plugger has a red rubber stop attached near the tip to mark the working length (WL). Clinical photo showing a dental handpiece equipped with a Gate Glidden bur actively removing GP material from a tooth's root canal. A purple rubber dam is visible in the background. A row of five Gate Glidden burs displayed vertically. These are rotary cutting instruments used for post space preparation, varying slightly in size or design features. Photo demonstrating the use of a dental handpiece with a Gate Glidden bur during post space preparation. The image illustrates the technique of using light vertical forces while the bur follows the path of insertion to avoid perforation. POST SPACE PREPARATION 3. Removal of GP Take a PA to verify if you reach the **WL** – post length that you calculated (remove GP from the canal walls before taking the PA), and to check the remaining apical GP. #### Radiographic Verification Take a PA to verify if the calculated working length (post length) has been reached. Ensure gutta percha is removed from the canal walls before taking the PA to check the remaining apical gutta percha. # POST SPACE PREPARATION ## 4. Post space preparation - Use ParaPost drills (ParaPost System) - Create parallel walls (let the drill make the work, do not tilt the drill) - Remove undercuts inside the canal - Establish the Width of the post **AVOID PERFORATION** - Drill following the root canal direction - Light vertical forces - Start with smaller drills and increase the size if necessary - Take PA if you are not sure if the bur is following the root canal   #### Post Space Preparation Technique - Use ParaPost drills (ParaPost System). - Create parallel walls; allow the drill to work without tilting. - Remove undercuts inside the canal. - Establish the width of the post. #### Perforation Prevention - Drill following the root canal direction. - Apply light vertical forces. - Start with smaller drills and increase size if necessary. - Take a PA if the bur's path is uncertain. Clinical photograph showing a set of five ParaPost drills arranged vertically. The drills feature silver metallic shafts with fluted cutting ends and are color-coded at the top (orange, yellow, blue, red, black) to indicate different sizes or types. Anatomical diagram illustrating post space preparation in a tooth cross-section. It shows a drill bit inserted into the root canal, demonstrating the process of creating parallel walls while avoiding perforation of the lateral root wall. The image visually reinforces the instruction 'let the drill make the work' by showing the tool's orientation. THE UNIVERSITY OF **WESTERN** AUSTRALIA Oral Health Centre of Western Australia --- POST SPACE PREPARATION **4. Post space preparation** - Establish the Width of the post - Increase post width, increase of retention and resistance - Wide post weaken the root (removal of tooth structure) - No more than 1/3 of the width of the root - Preserve buccal wall in upper incisors   #### Post Width Considerations - Increasing post width increases retention and resistance. - **Caution**: Wide posts weaken the root due to excessive removal of tooth structure. - Post width should be no more than 1/3 of the root width. - Preserve the buccal wall in upper incisors. Cross-sectional diagram of a tooth illustrating post space preparation guidelines. The image shows the root divided into three vertical sections (labeled '1/3'), with a central post occupying approximately one-third of the root's width to demonstrate retention and resistance principles while preserving structural integrity. Clinical intraoral photograph showing an upper incisor with a prepared access cavity for post placement. A black bracket measurement line spans the internal width of the canal opening, visually demonstrating the recommended post width limitation relative to the root structure mentioned in the text. **POST SPACE PREPARATION** 4. **Post space preparation** - Establish the Width of the post Select the size of ParaPost drill Minimum size for **Cast post** is **Yellow** (1 mm diameter) Minimum size for **Pre-fabricates** is **Brown** (0.9 mm)   #### ParaPost Drill Selection - **Cast Post**: Minimum size is Yellow (1 mm diameter). - **Prefabricated Post**: Minimum size is Brown (0.9 mm diameter). Clinical photograph of a set of dental ParaPost drills arranged vertically. The drills are metallic with distinct colored bands (black, purple, red, blue, yellow, brown) indicating different diameters. A color-coded legend chart displaying the diameter specifications for each drill size shown in the photo above. It maps colors to measurements: Black (Ø0.060" / 1.50 mm), Purple (Ø0.055" / 1.40 mm), Red (Ø0.050" / 1.25 mm), Blue (Ø0.045" / 1.14 mm), Yellow (Ø0.040" / 1.00 mm), and Brown (Ø0.036" / 0.90 mm). **THE UNIVERSITY OF WESTERN AUSTRALIA** Oral Health Centre of Western Australia POST SPACE PREPARATION **4. Post space preparation** - Establish the Shape of the post **Uniradicular teeth with minimal coronal structure:** - The post space should have elliptical shape to have an antirotational feature - If the canal is circular, create a small groove in the root canal following the path of insertion on the thickest wall Contemporary Fixed Prosthodontics 4ed   #### Post Shape for Uniradicular Teeth - For teeth with minimal coronal structure, the post space should have an elliptical shape to provide an antirotational feature. - If the canal is circular, create a small groove in the root canal following the path of insertion on the thickest wall. Cross-sectional diagram of a tooth showing post space preparation. The image displays the crown and root with an elliptical-shaped canal prepared for a post. A red line indicates the path of insertion on the thickest wall, demonstrating antirotational features for uniradicular teeth with minimal coronal structure. Clinical photograph of three adjacent teeth in a dental arch. The central tooth shows significant caries and decay at the cervical area, exposing the pulp chamber. This image illustrates the clinical context of preparing a post space in a tooth with compromised coronal structure. POST SPACE PREPARATION 4. Post space preparation - Establish the Shape of the post Multiradicular teeth with minimal coronal structure: • Use more than one canal to provide antirotational feature and improve retention Contemporary Fixed Prosthodontics 4ed  #### Post Shape for Multiradicular Teeth - For teeth with minimal coronal structure, use more than one canal to provide antirotational features and improve retention. Labelled anatomical diagram of a multiradicular tooth (likely a maxillary molar) in cross-section. The image shows the root structure with two visible roots and a crown sectioned to reveal internal anatomy. Labels include 'Lingual' on the left and 'Buccal' on the right. The context indicates this illustrates post space preparation for teeth with minimal coronal structure, showing how multiple canals may be used. **The University of Western Australia** **Oral Health Centre of Western Australia** POST SPACE PREPARATION 4. Post space preparation - Take a PA after the post space preparation to verify that there is no GP on the walls and confirm the final shape #### Final Verification Take a PA after post space preparation to verify that no gutta percha remains on the walls and to confirm the final shape. **The University of Western Australia | Oral Health Centre of Western Australia** **Should I remove existing temporary restoration and make the crown prep before or after the post space preparation?** **BEFORE:** * Better visualization of the canal * Know how much natural tooth structure will be left so you can plan the post space preparation accordingly (length, shape, antirotational) * Sometimes you lose the reference point for post space preparation (need a new PA and select another RP) #### Timing of Crown Preparation: Before Post Space Preparation Advantages of preparing the crown before the post space: - Better visualization of the canal. - Accurate assessment of remaining natural tooth structure for planning post length, shape, and antirotational features. - **Note**: Reference points for post space preparation may be lost, requiring a new PA and selection of a new reference point. The University of Western Australia | Oral Health Centre of Western Australia **Should I remove existing temporary restoration and make the crown prep before or after the post space preparation?** **BEFORE:** * Better visualization of the canal * Know how much natural tooth structure will be left so you can plan the post space preparation accordingly (length, shape, antirotational) * Sometimes you lose the reference point for post space preparation (need a new PA and select another RP) **AFTER:** * Maintain the reference point establish using the PA taken after the RCT * Easier to temporize during multi-appointment post space preparation #### Timing of Crown Preparation: Comparison **Before Post Space Preparation:** - Better visualization of the canal. - Accurate assessment of remaining natural tooth structure for planning. - Potential loss of original reference points. **After Post Space Preparation:** - Maintains the reference point established using the PA taken after root canal treatment (RCT). - Easier to provide temporary restorations during multi-appointment post space preparation. **Should I remove existing temporary restoration and make the crown prep before or after the post space preparation?** 1 or 5) Preparation of the coronal structure * Remove all existing restorations (temporary or definitive) * Eliminate undesirable undercuts (only for cast post and core) * Make the full crown preparation * Eliminate unsupported tooth structure (<2 mm) * Preparation of margins (create ferrule) * Positive horizontal stop Jotkowitz et al 2010, Contemporary Fixed Prosthodontics 4ed   #### Coronal Structure Preparation Steps - Remove all existing temporary or definitive restorations. - Eliminate undesirable undercuts (specifically for cast post and core). - Complete the full crown preparation. - Eliminate unsupported tooth structure (less than 2 mm). - Prepare margins to create a ferrule. - Establish a positive horizontal stop. Comparative diagram illustrating the importance of a positive horizontal stop in crown preparation. The left side shows an incorrect preparation with undercut walls (marked with a red 'X'), while the right side demonstrates the correct parallel or slightly tapered walls that provide retention for the post and core. Anatomical cross-section diagram of a tooth demonstrating specific preparation dimensions. It highlights the need to eliminate unsupported tooth structure (less than 2 mm) and illustrates the required wall thickness (1.5 - 2 mm) and positive horizontal stop at the finish line. **"Should I remove existing temporary restoration and make the crown prep before or after the post space preparation?"** **1 or 5) Preparation of the coronal structure** **LF Pegorario**  #### Preparation of the Coronal Structure Should I remove existing temporary restoration and make the crown prep before or after the post space preparation? Side-by-side clinical comparison photos illustrating the preparation of a coronal tooth structure. The left image shows a tooth with an existing temporary restoration and gingival tissue. The right image displays the same area after the temporary restoration has been removed, revealing the prepared post space (a circular void) within the tooth structure. POST SPACE PREPARATION Direct Technique | Impression Technique | Burn-out Resin Technique CAST POST AND CORE THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia  #### Post Space Preparation Methodologies - Direct Technique - Impression Technique - Burn-out Resin Technique Hierarchical flowchart diagram illustrating the classification of Post Space Preparation methods. The chart starts with a central green node labeled 'POST SPACE PREPARATION', which branches into three distinct categories: 'Direct Technique' (blue), 'Impression Technique' (yellow), and 'Burn-out Resin Technique' (orange). A red outline specifically highlights the latter two techniques. **The University of Western Australia | Oral Health Centre of Western Australia** **IMPRESSION TECHNIQUE** **INDICATION:** * **Multiple post and cores** * **Abutments of bridge (easier to establish parallelism)** * **Posterior teeth with divergent canals** **Advantage:** * **Faster clinical procedure compared to burn-out resin** * **Lab will manufacture the post** **Disadvantage:** * **May introduce errors (distortion during impression and pour-up)** * **May need more adjustments during try-in**   #### Clinical Indications - Multiple post and cores - Abutments of bridge (easier to establish parallelism) - Posterior teeth with divergent canals #### Advantages - Faster clinical procedure compared to burn-out resin - Laboratory will manufacture the post #### Disadvantages - May introduce errors (distortion during impression and pour-up) - May need more adjustments during try-in Clinical intraoral photograph showing multiple teeth with post and core restorations. The left panel displays an anterior view of the upper jaw with visible metal posts in extracted tooth sockets and prepared abutments for a bridge. The right panel shows an occlusal view of the same arch, highlighting divergent canal structures and existing metallic crowns. Photograph of a dental cast model demonstrating divergent root canals (likely molars) after impression-taking and pouring, illustrating the complexity addressed by this technique. # IMPRESSION TECHNIQUE - Use full arch stock tray or custom tray - Dry the canal (air and paper points) - Verify the impression post seating - Apply the light body PVS - Seat the impression post - Apply heavy/medium body on the tray - Insert the tray - Remove the tray with 'snap' movement      #### Clinical Procedure 1. Use full arch stock tray or custom tray 2. Dry the canal (air and paper points) 3. Verify the impression post seating 4. Apply the light body PVS 5. Seat the impression post 6. Apply heavy/medium body on the tray 7. Insert the tray 8. Remove the tray with 'snap' movement Clinical photo demonstrating the first step of the impression technique: drying the canal. The image shows a dental model with teeth and a prepared root canal being dried using a paper point held by tweezers. Clinical photo illustrating the application of light body PVS to the tray and seating the impression post. A blue tube (likely the light body material) is shown dispensing into the impression post area on the dental model. Clinical photo showing the final stage of seating the impression post after applying heavy/medium body material. The impression post is fully seated in the prepared tooth socket on the dental model. Visual reference for materials used in the procedure. Shows a red stock impression tray against a yellow background. Visual reference for materials used in the procedure. Shows blue silicone impression material applied to a dental stone cast, likely representing the heavy/medium body PVS mentioned in the text. **IMPRESSION TECHNIQUE** - Lab pour up the model and create a burn-out resin post and core - Cast post and core <Pegoraro>    #### Laboratory Phase - Laboratory pours up the model and creates a burn-out resin post and core - Cast post and core fabrication Clinical photo showing a dental stone model of an upper jaw with several red resin posts inserted into prepared root canals. This illustrates the 'burn-out resin post and core' step mentioned in the OCR text. Clinical photo showing a close-up of the same dental model with red burn-out posts placed in the prepared sites. This visualizes the intermediate stage before casting. Clinical photo showing the final cast metal post and core structure emerging from the pink impression material on the dental model. This demonstrates the result of the 'Cast post and core' step described in the text. # BURN-OUT RESIN TECHNIQUE INDICATION: * University or multiradicular teeth without Divergent root canals CONTRA INDICATION: * Patients allergic to monomer * Patients who cannot stay with the mouth open for long period of time * Divergent roots Advantage: * You have control of the shape of the post and core * Less adjustments during try-in (not always!) Disadvantage: * More difficult method * More clinical time is necessary THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia #### Indications - Uniradicular or multiradicular teeth without divergent root canals #### Contraindications - Patients allergic to monomer - Patients who cannot stay with the mouth open for long period of time - Divergent roots #### Advantages - Clinician has control of the shape of the post and core - Less adjustments during try-in (not always) #### Disadvantages - More difficult method - More clinical time is necessary # The University of Western Australia | Oral Health Centre of Western Australia ## BURN-OUT RESIN TECHNIQUE - Dry the canal (air and paper points) - Select the size of the burn-out post - Apply separator in the canal and coronal structure - Apply acrylic resin (Duralay or Pattern Resin) inside the canal and around the burn-out post (bead-brush technique) – PASSIVE FIT - Insert the burn-out post into the canal - Wait until the acrylic starts to set, and then make in and out movements until the acrylic polymerize      #### Clinical Procedure: Post Modeling 1. Dry the canal (air and paper points) 2. Select the size of the burn-out post 3. Apply separator in the canal and coronal structure 4. Apply acrylic resin (Duralay or Pattern Resin) inside the canal and around the burn-out post using the bead-brush technique to ensure a passive fit 5. Insert the burn-out post into the canal 6. Wait until the acrylic starts to set, and then make in and out movements until the acrylic polymerizes Photo showing the preparation phase: left panel shows a finger holding a white burn-out post with a metal pin inserted; right panel shows two small glass containers—one green and one pink—likely containing separator or acrylic resin materials. Photo demonstrating the application of red acrylic resin (Duralay or Pattern Resin) into the canal of a white tooth model using a bead-brush technique. The text specifies this step involves applying resin inside the canal and around the burn-out post for a passive fit. Photo illustrating the polymerization phase: a clear plastic tool is shown making in-and-out movements within the canal filled with partially set red acrylic resin, as described in the procedure to ensure proper curing. Close-up photo of a red textured surface, likely representing the cross-section or texture of the acrylic resin material used in the burn-out post technique. Diagram/photo combination showing the final assembly step: a white tooth model with a red burn-out post inserted into its canal. A double-headed arrow indicates the 'in and out' motion required during polymerization as per the textual instructions. **BURN-OUT RESIN TECHNIQUE** - Build up the core **after** the modeling of the post, - Apply the Duralay to reestablish the missing coronal structure (do not overbuild) - Make the crown preparation - Remove the handle and check occlusal clearance (MIP and excursion) - Send the acrylic post and core to the lab for cast Mori, Pegorano #### Clinical Procedure: Core Build-up and Preparation 1. Build up the core after the modeling of the post 2. Apply the Duralay to reestablish the missing coronal structure (do not overbuild) 3. Make the crown preparation 4. Remove the handle and check occlusal clearance (MIP and excursion) 5. Send the acrylic post and core to the lab for casting **POSTERIOR TEETH - CAST POST AND CORE** - No coronal structure to support the core material - Use more than one post **Divergent canals** - Multipiece cast post and core - More retention - Impression technique **** **** **** **** **Main Post** Upper molars: Palatal Lower molars: Distal **Contemporary Fixed Prosthodontics 4th ed**   #### Clinical Considerations - Used when there is no coronal structure to support the core material - Use more than one post #### Management of Divergent Canals - Multipiece cast post and core - Provides more retention - Utilizes the impression technique #### Selection of Main Post - **Upper molars:** Palatal canal - **Lower molars:** Distal canal Clinical comparison of cast post and core designs. Left panel shows a single-piece metal post with parallel canals; right panel shows a multipiece post in divergent canals. Series of four dental models illustrating the construction and fit of a multipiece cast post and core for posterior teeth with divergent canals, showing individual components and final assembly. **POST SPACE PREPARATION** **Direct Technique** **Impression Technique** **Burn-out Resin Technique** **THE UNIVERSITY OF WESTERN AUSTRALIA** | **Oral Health Centre of Western Australia**  #### Post Space Preparation Methods - Direct Technique - Impression Technique - Burn-out Resin Technique Hierarchical flowchart diagram illustrating the categories of 'POST SPACE PREPARATION'. The top node branches into three sub-categories: 'Direct Technique' (highlighted with a red border), 'Impression Technique', and 'Burn-out Resin Technique'. University branding is present at the top. **DIRECT TECHNIQUE** *(Pre-fabricated post)* Improve core retention • Leave undercuts (help retention) • Add pins if necessary (extra retention) • Use amalgam tags in other canals (amalgam core in posterior teeth)  #### Strategies to Improve Core Retention - Leave undercuts to assist with retention. - Add pins if necessary for extra retention. - Use amalgam tags in other canals when performing an amalgam core in posterior teeth. Anatomical diagram of a posterior tooth (molar or premolar) illustrating the 'Direct Technique' for a pre-fabricated post. The image displays a cross-section showing two root canals with pink pulp tissue and a central amalgam core (tan color) built up between them. A white outline at the bottom represents the gingival margin. This visual demonstrates the placement of an amalgam core in posterior teeth to improve retention, as described by the text. **<u>DIRECT TECHNIQUE</u>** **(Pre-fabricated post)** * Dry the canal (air and paper points) * Select the size (diameter) of the pre-fabricated post that fits tight in the post space (same as the last Parapost drill used) * Check the length of the post according to the interarch space * Adjust the length by cutting the apical end if needed (post completely embedded in the core material) * Clean the post space (saline) and dry very well (paper points) **Cementation:** Resin cement (e.g. Panavia) – metal and fiber post GIC and RMGIC (e.g. Permacem) – metal After cementation, wait the complete setting (at least 10 min)     #### Post Selection and Preparation 1. Dry the canal using air and paper points. 2. Select the size (diameter) of the pre-fabricated post that fits tightly in the post space. This should correspond to the size of the last Parapost drill used. 3. Check the length of the post according to the available interarch space. 4. Adjust the length by cutting the apical end if needed, ensuring the post will be completely embedded in the core material. 5. Clean the post space with saline and dry thoroughly with paper points. #### Cementation Protocols - **Resin cement (e.g., Panavia):** Used for metal and fiber posts. - **GIC and RMGIC (e.g., Permacem):** Used for metal posts. After cementation, allow for the complete setting of the material (at least 10 minutes). Clinical photo showing an open tooth cavity with the pulp chamber exposed. The surrounding gingiva is visible, and the tooth structure shows signs of decay or preparation. Product photograph of a prefabricated dental post. It is a slender, cylindrical object with a textured surface, likely made of metal or fiber-reinforced composite, shown against a neutral background. Clinical photo demonstrating the insertion step of the direct technique. A prefabricated post has been placed into the prepared root canal space of the tooth. The fit appears tight as per the instructions in the text. Clinical photo demonstrating the cementation step of the direct technique. A translucent cement material (likely resin cement like Panavia) is being applied over the inserted post to secure it within the tooth structure. **DIRECT TECHINIQUE** (Pre-fabricated post) *** • Core build-up *** *** Before crown prep After crown prep   #### Core Build-up Stages - Core build-up - Before crown preparation - After crown preparation Clinical photo of a tooth showing the state before crown preparation. The image displays a central incisor with a visible post and core build-up material (brownish) at the gum line, flanked by adjacent healthy teeth. Clinical photo of the same tooth after crown preparation. The image shows the tooth structure has been reduced to create space for a crown, while retaining the pre-fabricated post and core build-up at the gingival margin. Schwartz and Robbins. Post Placement and Restoration of Endodontically Treated Teeth: A Literature Review. Journal Of Endodontics. 30(5) 2004 Fernandes et al. Factors determining post selection: a literature review. The Journal of Prosthetic Dentistry 90(6), 556-562. 2003 Peutzfeldt et al A survey of failed post-retained restorations/ Clin Oral Invest (2008) 12:37–44 Figueiredo et al. Do Metal Post–retained Restorations Result in More Root Fractures than Fiber Post–retained Restorations? A Systematic Review and Meta-analysis. J Endod 2015;41:309–316 Rosenstiel et al. Contemporary Fixed Prosthodontics 4th ed Jotkowitz et al. Rethinking ferrule – a new approach to an old dilemma. British Dental Journal 2010; 209: 25–33 - Schwartz and Robbins. Post Placement and Restoration of Endodontically Treated Teeth: A Literature Review. Journal Of Endodontics. 30(5) 2004 - Fernandes et al. Factors determining post selection: a literature review. The Journal of Prosthetic Dentistry 90(6), 556-562. 2003 - Peutzfeldt et al. A survey of failed post-retained restorations. Clin Oral Invest (2008) 12:37–44 - Figueiredo et al. Do Metal Post–retained Restorations Result in More Root Fractures than Fiber Post–retained Restorations? A Systematic Review and Meta-analysis. J Endod 2015;41:309–316 - Rosenstiel et al. Contemporary Fixed Prosthodontics 4th ed - Jotkowitz et al. Rethinking ferrule – a new approach to an old dilemma. British Dental Journal 2010; 209: 25–33 [^1]: Original PDF page 1: [[L3_RETT_2026_Post and Core Fabrication Techniques.pdf#page=1|L3 RETT 2026 Post and Core Fabrication Techniques, p.1]] [^2]: Original PDF page 2: [[L3_RETT_2026_Post and Core Fabrication Techniques.pdf#page=2|L3 RETT 2026 Post and Core Fabrication Techniques, p.2]] [^3]: Original PDF page 3: [[L3_RETT_2026_Post and Core Fabrication Techniques.pdf#page=3|L3 RETT 2026 Post and Core Fabrication Techniques, p.3]] [^4]: Original PDF page 4: [[L3_RETT_2026_Post and Core Fabrication Techniques.pdf#page=4|L3 RETT 2026 Post and Core Fabrication Techniques, p.4]] [^5]: Original PDF page 5: [[L3_RETT_2026_Post and Core Fabrication Techniques.pdf#page=5|L3 RETT 2026 Post and Core Fabrication Techniques, p.5]] [^6]: Original PDF page 6: [[L3_RETT_2026_Post and Core Fabrication Techniques.pdf#page=6|L3 RETT 2026 Post and Core Fabrication Techniques, p.6]] [^7]: Original PDF page 7: [[L3_RETT_2026_Post and Core Fabrication 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