# Surveying Procedures Dr Matsubara The University of Western Australia | Oral Health Centre of Western Australia Dr Matsubara The University of Western Australia | Oral Health Centre of Western Australia # Survey and Design **THE UNIVERSITY OF WESTERN AUSTRALIA** | **Oral Health Centre of Western Australia** ## Learning outcomes * Discuss the importance of study models * Discuss the importance of surveying for the fabrication of an RPD * Describe all steps of dental surveying * Define the position of rest/rest seat, undercuts, minor and major connectors * Describe the adjustment of the high of contour on abutment teeth #### Objectives of Study and Design - Discuss the importance of study models - Discuss the importance of surveying for the fabrication of a Removable Partial Denture (RPD) - Describe all steps of dental surveying - Define the position of rest/rest seat, undercuts, minor and major connectors - Describe the adjustment of the height of contour on abutment teeth # Survey and Design ## The University of Western Australia Oral Health Centre of Western Australia ### Study Model **Dental stone (Type III gypsum)** **Function:** * **Analysis** of models mounted on the articulator * Interim RPD* * Surveying (**Design** of the RPD framework) * Fabricate custom tray     #### Materials and Applications Study models are typically constructed using **Dental stone (Type III gypsum)**. #### Primary Functions - **Analysis**: Evaluation of models mounted on the articulator. - **Interim RPD**: Construction of temporary removable partial dentures. - **Surveying**: Facilitating the design of the RPD framework. - **Custom Tray Fabrication**: Creating individualized impression trays. Clinical photo showing a dental study model (Type III gypsum) mounted on an articulator. The upper cast is seated in the lower jaw of the articulator, demonstrating the mounting process for analysis or fabrication as referenced in the text. Clinical photo of a dental study model with survey lines drawn in red and yellow to illustrate the design of an RPD framework. This corresponds to the 'Surveying' function mentioned in the text. Line diagram illustrating a lateral view of the mandible and maxilla with a horizontal line representing the occlusal plane or survey line across the teeth. Schematic diagram showing a simplified representation of teeth with arrows indicating direction of force or movement, likely related to the design of the RPD framework or surveying process. **Survey and Design** **SURVEYING PROCESS** **AIMS:** * Define the shape, form and contours of teeth and associated structures that will influence the RPD design * Identify modifications of dental structures required to optimize RPD design * Allows selection of Path of Insertion most compatible with: * Aesthetic requirements * Guiding plane location * Retention - location and depth of undercut * Hard & soft tissues interferences ### Image contents  #### Objectives of the Surveying Process The primary aims of surveying are to: - Define the shape, form, and contours of teeth and associated structures that will influence the Removable Partial Denture (RPD) design. - Identify modifications of dental structures required to optimize RPD design. - Facilitate the selection of a Path of Insertion most compatible with: - Aesthetic requirements - Guiding plane location - Retention (location and depth of undercut) - Hard and soft tissue interferences Photograph of a dental surveyor in use. The image shows the metal instrument positioned over a white stone cast of teeth. The device features a vertical post and an articulated arm with a pointer tip touching the surface of the dental model to demonstrate the process of defining contours and paths of insertion. # **Survey and Design** ## **Surveying Process** ### **Steps:** 1. **Preliminary visual assessment** 2. **Determine the path of insertion** 3. **Mark the height of contour of teeth (identifying the retentive area)** 4. **Define the position of rest** 5. **Identify the desired undercut** 6. **Draw the outline of the framework** 7. **Adjust the height of contour and create guiding planes**       #### Sequential Steps in Surveying 1. Preliminary visual assessment 2. Determine the path of insertion 3. Mark the height of contour of teeth (identifying the retentive area) 4. Define the position of rest 5. Identify the desired undercut 6. Draw the outline of the framework 7. Adjust the height of contour and create guiding planes Schematic diagram illustrating the surveying process. It depicts a dental cast with an overlay indicating the path of insertion (blue lines) and the height of contour line (red line). Clinical photograph showing a dental surveyor tool positioned against a tooth on a model to determine the path of insertion. Close-up clinical photograph demonstrating the marking of the height of contour on a tooth using the surveyor indicator. Photograph of a complete upper dental cast with red markings outlining the retentive areas and framework design. Photograph showing a lower dental cast with a red pencil pointing to a specific area, likely demonstrating the definition of rest position or undercut identification. Close-up clinical photograph showing the adjustment of the height of contour or creation of guiding planes on a tooth using the surveyor tool. # Survey and Design THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia 1) PRELIMINARY VISUAL ASSESSMENT Simple visual assessment made by the clinician, with the cast being viewed from above. * Kennedy classification * Fulcrum line(s) * Potential rest seat location * Indirect retention  A simple visual assessment is made by the clinician, with the cast being viewed from above. This initial review should identify: - Kennedy classification - Fulcrum line(s) - Potential rest seat location - Indirect retention Clinical photograph of a maxillary dental cast viewed from above. The image displays an arch form with anterior teeth and molars on the left and right posterior regions. Two specific molar units are highlighted with white circles, indicating potential abutment sites for a removable partial denture design. **Survey and Design** 1) **PRELIMINARY VISUAL ASSESSMENT** Simply a visual assessment made by the clinician, with the cast being viewed from above. Relative parallelism of proximal tooth surfaces to be considered for the first time A visual assessment is made by the clinician with the cast viewed from above. During this stage, the relative parallelism of proximal tooth surfaces should be considered for the first time. # Survey and Design **The University of Western Australia** | Oral Health Centre of Western Australia 1) PRELIMINARY VISUAL ASSESSMENT > Simply a visual assessment made by the clinician, with the cast being viewed from above. > Relative parallelism of proximal tooth surfaces to be considered for the first time > Gross problems relating to interference, contour and undercuts can be identified. The clinician performs a visual assessment by viewing the cast from above. #### Initial Considerations - Relative parallelism of proximal tooth surfaces is considered for the first time. - Gross problems relating to interference, contour, and undercuts can be identified. # Survey and Design 1) **PRELIMINARY VISUAL ASSESSMENT** - Decide potential rest seat locations -mark with vertical black lines on bases. - - From posterior aspect mark vertical overlap.   - Decide potential rest seat locations and mark with vertical black lines on bases. - From the posterior aspect, mark the vertical overlap. Clinical photo demonstrating the marking of potential rest seat locations. Two images show a dental cast with a pencil drawing vertical black lines on the occlusal surface of the teeth bases. Close-up clinical photos showing markings on anterior teeth. The left image shows a pencil marking a line across the incisal edges from a posterior view. The right image highlights the 'Incisal limit of casting' with an arrow and text box annotation. # Survey and Design ## 2) Path of Insertion Roach technique (three points) ### MAXILLA Contact point 11 and 21 Marginal ridge of molars    The path of insertion is determined using the Roach technique, which utilizes a three-point reference system. #### Maxillary Reference Points To establish the reference plane for the maxilla, identify the following three points: - The contact point between teeth 11 and 21. - The marginal ridges of the molars. Clinical photo of a maxillary dental cast showing the surveyor contact point at tooth positions 11 and 21 (lateral incisors), demonstrating the Roach technique for path of insertion. Clinical photo of a maxillary dental cast showing the surveyor tip positioned at the marginal ridge of the molars, illustrating the second point of the Roach technique for establishing path of insertion. Clinical photo of a maxillary dental cast showing the surveyor tip positioned near the anterior teeth region, completing the three-point Roach technique setup for determining path of insertion in the maxilla. Survey and Design 2) Path of Insertion Roach technique (three points)  Roach technique (three points) Clinical procedure image demonstrating the Roach technique for path of insertion in dentistry. The image shows a dental cast with an overlay illustrating the occlusal table parallel to the base of the surveyor (indicated by red lines). A large yellow arrow points downward, indicating the direction of insertion, while a black instrument is shown engaging the tooth structure.  Clinical diagram demonstrating the Roach technique for determining the path of insertion on a mandibular cast. A yellow arrow points downward from the incisal edge region toward the anterior teeth, indicating the direction of insertion. Three red dots mark key survey points: one at the incisal edge of incisors and two at the marginal ridges of molars. Yellow lines connect these points to form a triangle, illustrating how the path of insertion is derived from these three reference points. # Survey and Design THE UNIVERSITY OF WESTERN AUSTRALIA | Oral Health Centre of Western Australia 2) Path of Insertion Roach technique (three points) **MANDIBLE** Mesial marginal ridges of pre-molars Marginal ridge of molars  #### Mandibular Reference Points To establish the reference plane for the mandible, identify the following three points: - The mesial marginal ridges of the pre-molars. - The marginal ridges of the molars. Labelled diagram of a mandibular dental cast illustrating the 'Roach technique' for determining path of insertion. A yellow arrow points downwards to indicate the direction of insertion. Four black dots mark specific anatomical landmarks: two on the mesial marginal ridges of pre-molars and two on the marginal ridge of molars. Yellow lines connect these points to form a reference plane. **Survey and Design** **2) Path of Insertion** **Roach technique (three points)** **Create the reference with wax** **THE UNIVERSITY OF WESTERN AUSTRALIA** **Oral Health Centre of Western Australia**      #### Reference Creation Create the reference with wax. Clinical photo of a dental cast showing the maxillary arch with red and blue markings indicating survey lines or path of insertion guides. The image relates to the 'Roach technique' mentioned in the text. Clinical photo of a lower dental cast (mandibular) made of plaster or stone, showing teeth and surrounding anatomy. Likely used as a base for demonstrating the wax-up procedure described in the text. Diagram illustrating the Roach technique for creating a reference with wax. It shows a cross-section of a dental cast with two vertical blue lines representing guide pins or surveyor arms, and an orange block representing wax material placed on the cast surface. Image of several translucent red rectangular sheets, likely representing sheet wax used in dentistry for creating paths of insertion or other procedural references. Image of pink rectangular blocks of wax, possibly modeling wax or bite registration material, arranged in a stack. These are materials used in the described dental procedure. **Survey and Design** **3) Height of Contour** Survey lines of supporting teeth   Survey lines of supporting teeth Clinical photo showing a dental surveyor instrument being used to mark the height of contour on a lower jaw dental cast. The metal stylus is positioned on the buccal surface of the teeth, and a black line has been drawn along the contour. Clinical photo showing a close-up view of the same procedure on an upper or lower dental cast. The surveyor tip is marking the height of contour on the interproximal area between two posterior teeth, with a visible survey line extending along the tooth surfaces. **Survey and Design** **3) Height of Contour** **Survey lines of supporting tissues:** The extend of supporting tissue undercuts defines whether an infra-bulge retainer is possible **Infra-bulge retainers:** Desire 3 mm of attached gingivae from free gingival margin to top of the undercut   #### Impact on Retainer Selection The extent of supporting tissue undercuts defines whether an infra-bulge retainer is possible. #### Requirements for Infra-bulge Retainers - Desire 3 mm of attached gingivae from the free gingival margin to the top of the undercut. Clinical photograph demonstrating a correct survey line on a dental cast. A metal surveying instrument is shown measuring the undercut of a tooth. The image features red text 'OK' and a vertical double-headed arrow indicating the proper height of contour measurement required for an infra-bulge retainer. Clinical photograph demonstrating an incorrect survey line on a dental cast. A metal surveying instrument is positioned over a tooth with a visible undercut. The image features red text 'Not OK' and a horizontal red arrow pointing to the undercut area, illustrating why this contour prevents the use of an infra-bulge retainer. **Survey and Design** 3) Height of Contour Survey lines of supporting tissues: The extent of supporting tissue undercuts defines whether an infra-bulge retainer is possible   The extent of supporting tissue undercuts defines whether an infra-bulge retainer is possible. Clinical photo showing a dental surveying instrument (a probe or pointer) demonstrating an undercut on a tooth model. The visual illustrates the concept of tissue undercuts relevant to retainer design. Clinical photo of a cast with a metal partial denture framework in place, labeled 'Ideal'. This image demonstrates the proper placement and fit of a retainer compared to the undercut condition shown previously. **Survey and Design** 3) Height of Contour Survey lines of supporting tissues: The extent of supporting tissue undercuts defines whether an infra-bulge retainer is possible  The extent of supporting tissue undercuts defines whether an infra-bulge retainer is possible. Line drawing diagram illustrating the 'Height of Contour' and 'Survey lines of supporting tissues'. The image depicts a cross-section of a tooth root with an infra-bulge retainer design. A grey, hook-shaped retainer arm is shown engaging the undercut area below the height of contour, indicated by a red curved arrow demonstrating the path of insertion. **Survey and Design** **3) Height of Contour** Soft tissues undercuts - bony protuberances that interfere with the seating of the denture base/major connector • Change POI, • Use a major connector design that avoids the bulky area • Pre-prosthetic surgery  #### Management of Bony Protuberances Soft tissue undercuts often involve bony protuberances that interfere with the seating of the denture base or major connector. Management strategies include: - Change the Path of Insertion (POI). - Use a major connector design that avoids the bulky area. - Perform pre-prosthetic surgery. Labelled diagram showing two stages of soft tissue undercut interference. Top panel: A denture base/major connector (grey block) is shown approaching a bony protuberance on the gumline with a downward arrow indicating seating force; the contour allows space for seating. Bottom panel: The same setup but the denture base hits the bony protuberance directly, causing an obstruction indicated by a black arrow and radiating lines representing impact or inability to seat. This visual demonstrates how soft tissue undercuts interfere with denture seating. **Survey and Design** **THE UNIVERSITY OF WESTERN AUSTRALIA** | **Oral Health Centre of Western Australia** 3) Height of Contour This causes food entrapment and aesthetic issues Buccal flange not only aid the aesthetics but also assist in the retention and stability of the RPD  #### Clinical Implications Soft tissue undercuts can cause food entrapment and aesthetic issues. #### Role of the Buccal Flange The buccal flange not only aids in aesthetics but also assists in the retention and stability of the Removable Partial Denture (RPD). Medical diagram illustrating the 'Height of Contour' for a Removable Partial Denture (RPD). The image compares two scenarios: the top panel shows an incorrect contour causing food entrapment and aesthetic issues, indicated by a black upward arrow. The bottom panel shows the correct contour where the buccal flange aids retention and stability, indicated by a black diagonal arrow and a yellow downward arrow. **Survey and Design** 2) Path of Insertion The final path of placement will be the anteroposterior and lateral position of the cast, in relation to the vertical arm of the surveyor, that best satisfies **retention**, **guiding planes**, **interference**, and **esthetics**. Convenience technique (Applegate technique) #### Determining the Path of Insertion The final path of placement is determined by the anteroposterior and lateral position of the cast in relation to the vertical arm of the surveyor. This position must best satisfy the following four requirements: - **Retention** - **Guiding planes** - **Interference** - **Esthetics** #### Convenience Technique This method is also referred to as the Applegate technique. **Survey and Design** **2) Path of Insertion** **Lateral tilt** Ideal: reasonable retention is balanced out between all the abutment teeth  #### Lateral Tilt Considerations The ideal lateral tilt is achieved when reasonable retention is balanced out between all the abutment teeth. Diagram illustrating the 'Path of Insertion' and 'Lateral tilt' concept in dental surveying. It features two comparative panels: top panel labeled 'Before Applegate technique' shows a horizontal casting with abutment teeth tilted laterally (indicated by red arrows); bottom panel labeled 'After Applegate technique' shows the same setup but with the entire cast tilted to align the path of insertion, balancing retention between abutment teeth. Survey and Design **Anterior-posterior tilt** Establish adequate guiding planes, without cutting too much tooth structure Before Applegate technique After Applegate technique 2) Path of Insertion **THE UNIVERSITY OF WESTERN AUSTRALIA** Oral Health Centre of Western Australia    #### Anterior-Posterior Tilt Considerations The objective of the anterior-posterior tilt is to establish adequate guiding planes without excessive removal of tooth structure. - **Before Applegate technique**: Initial assessment of tooth morphology and potential guiding planes. - **After Applegate technique**: Finalized path of insertion following the convenience technique adjustments. Labelled diagram titled 'Before Applegate technique'. Shows two schematic representations of dental casts (a molar and an incisor) on a tilted plane. The diagrams illustrate the anterior-posterior tilt problem where the guiding planes are not parallel to the path of insertion. Procedure image showing the Applegate technique in action. Two stacked photos depict gloved hands manipulating a dental cast on a surveyor machine. The top photo shows the initial position, and the bottom photo shows the cast being adjusted or locked into place to establish parallelism. Labelled diagram titled 'After Applegate technique'. Shows two schematic representations of the same dental casts as the 'before' image. These diagrams illustrate the corrected state where the guiding planes are parallel to the path of insertion, ensuring adequate clearance for the prosthesis. **Survey and Design** (header) **2) Path of Insertion** Record and reproduce the model position **Tripoding the cast** Procedure that allows **casts** to be placed back on the survey table in the same pre-established orientation (when the framework design was done) Two methods: * Horizontal Plane * Vertical Plane #### Purpose of Tripoding Tripoding is the procedure that allows casts to be placed back on the survey table in the same pre-established orientation used during the framework design. This ensures the record and reproduction of the model position. #### Methods of Tripoding There are two primary methods used to tripod a cast: 1. Horizontal Plane 2. Vertical Plane Survey and Design The University of Western Australia | Oral Health Centre of Western Australia 2) Path of Insertion Record and reproduce the model position Tripoding the cast * Horizontal Plane * With the vertical arm of the surveyor LOCKED, three wide-spread tissue points are selected in relatively non-critical areas that can be marked for future identification * When repositioning the cast, the table is maneuvered until the three points coincide with the vertical arm fixed in a position.    #### Horizontal Plane Method - With the vertical arm of the surveyor locked, three wide-spread tissue points are selected in relatively non-critical areas that can be marked for future identification. - When repositioning the cast, the survey table is maneuvered until all three points coincide with the fixed vertical arm. Diagram illustrating the 'Tripoding' procedure. A dental cast is mounted on a surveyor table with three points marked by '+' signs to establish a horizontal plane for repositioning. Clinical photograph of a dental cast being positioned in a vertical articulator using a tripod setup. The instrument arm is inserted into the model to secure its orientation. Close-up image of a dental cast showing the physical markers (red circles and crosses) placed on the model to identify the tripod points used for path of insertion analysis. # Survey and Design ## 2) Path of Insertion Record and reproducethe model position ### Tripoding the cast ### Vertical Plane - Analysing rod as a guide ruler - Create three parallel divergent markings on the dorsal and the two lateral sides of the cast. - These lines can then be used to re-orientate the cast to the original plane    #### Vertical Plane Method - The analyzing rod is used as a guide ruler. - Three parallel divergent markings are created on the dorsal and the two lateral sides of the cast. - These lines are used to re-orientate the cast to the original plane. Black and white line drawing illustrating the 'Tripoding' process. A dental cast is mounted on a base, with an analysing rod positioned vertically against it. A pencil marks lines on the cast's surface, demonstrating the creation of divergent markings as described in the text. Illustration showing a dental cast secured in a tripod mount (three-pronged holder) attached to a vertical stand. An analysing rod is inserted into the mount, and a pencil marks the cast, visually representing the steps for establishing the vertical plane. Close-up illustration of the tripod mounting mechanism holding a dental cast. It shows the vertical positioning of the analysing rod and the specific placement of the three prongs supporting the model, corresponding to the 'Vertical Plane' analysis section. Survey and Design THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia 2) Path of Insertion Record and reproduce the model position  Record and reproduce the model position. Three-panel clinical photograph sequence demonstrating the 'Path of Insertion' step in a removable partial denture procedure. The panels show: (left) a dental cast mounted on an articulator with a vertical metal pin inserted through the model to record orientation; (center) a top-down view of the cast showing the red-wax path-of-insertion indicator and pencil markings for clasp positions; (right) the same cast viewed from above with red wax borders applied along the denture flanges, illustrating how the recorded path guides the placement of the prosthetic framework. Survey and Design 4) Rest position • Intercalated edentulous area: adjacent to the edentulous area • Free-end edentulous area: not immediately adjacent to the saddle. THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia  #### Placement Guidelines Based on Edentulous Areas - **Intercalated edentulous area**: Position the rest adjacent to the edentulous area. - **Free-end edentulous area**: Position the rest so it is not immediately adjacent to the saddle. Three labeled diagrams illustrating rest position concepts in dentistry. Left: Intercalated edentulous area diagram showing a complete arch with red horizontal lines indicating parallel planes across adjacent teeth; blue dots mark contact points between saddle and abutment teeth. Middle: Free-end edentulous area diagram depicting an arch with tilted red lines representing non-parallel planes due to missing posterior teeth; one tooth is shown as a removable partial denture (RPD) attachment point. Right: Another free-end edentulous area diagram with curved yellow arrow indicating rotational movement or stress direction on the saddle; red line shows plane of force application. **4) Rest position**  Rest position Educational diagram illustrating the 'Rest position' in dentistry (context from OCR). The visual shows four separate panels of a dental arch (palate view) with red lines indicating surveyor angles and yellow curved arrows demonstrating rotational movement. Blue dots mark specific points on the teeth. This figure is part of a larger slide titled 'Survey and Design'. <header> Survey and Design THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia </header> H) Rest position  Rest position Medical diagram illustrating 'Rest position' in dental survey and design. Left panel shows a posterior tooth with a red circle highlighting the occlusal surface; middle panel displays an occlusal view of a molar with a dark blue shaded area indicating rest seat placement; right panel depicts a maxillary arch model with four dark blue spots marking rest positions on premolars and molars. **Survey and Design** # 5) Desired undercut **CoCr**   **CoCr** Clinical photo of three CoCr (Cobalt-Chromium) surveyor rods labeled '.01"', '.02"', and '.03"' to demonstrate different undercut depths. Red arrows point to the specific measurement zones on each rod. Schematic diagram illustrating a dental surveying procedure. It shows a black T-shaped instrument positioned next to a line drawing of a tooth outline, demonstrating the concept of 'Desired undercut' mentioned in the slide title. Survey and Design 5) Desired undercut **CoCr**     **CoCr** Photograph of three metallic surveyor rods labeled .01", .02", and .03" showing graduated markings. Red arrows point to specific depths on the rods, demonstrating measurement increments for CoCr (Cobalt-Chromium) casting thickness. Line drawing of a tooth with a black survey line outlining the preparation margin. A red arrow points to the undercut area below the survey line, illustrating the desired depth relative to the vertical guide rod shown in profile. Clinical photograph showing a metal surveyor rod touching the prepared tooth surface. A red arrow indicates the contact point where the survey line is marked on the tooth structure. Schematic illustration of a crown preparation with a thin metal ring representing the casting margin. A small red dot marks the location of the undercut, corresponding to the desired depth indicated by the title 'Desired undercut'. **Survey and Design** 6) Outline of the framework 1° Rests 2° Grid 2/3  The initial components to be outlined on the framework include: 1. Rests 2. Grid Anatomical diagram of the maxillary arch showing a partial denture framework design. The image includes red dashed outlines indicating the path of the framework and black rectangular structures representing the major connectors or rests on the buccal cusps of posterior teeth. Labels include 'Survey and Design', '6) Outline of the framework', '1° Rests', '2° Grid', and '2/3'. The diagram is associated with The University of Western Australia and Oral Health Centre of Western Australia. Survey and Design 6) Outline of the framework 1° Rests 2° Grid 3° Clasps: retention arm (supra and infra-bulge), reciprocating arm, proximal plate      The design process continues with the placement of rests and grids, followed by the specification of clasps: - **Clasps** - Retention arm (including supra-bulge and infra-bulge designs) - Reciprocating arm - Proximal plate Diagram illustrating a dental rest (highlighted in yellow) on the occlusal surface of a posterior tooth. It demonstrates the position relative to the height of contour, indicated by dashed lines. Cross-sectional diagram of a tooth showing a clasp assembly. The retention arm is highlighted in yellow, extending from the reciprocal arm, demonstrating engagement with the tooth structure. Labeled diagram of a tooth illustrating a clasp design. The clasp components are colored yellow and white against the tooth outline. Labels '1/3' appear on the right side, likely indicating thirds of the tooth height for positioning the clasp arms. Schematic drawing of a dental framework on a tooth model. Key components are labeled with letters: 'T' for the T-bar or proximal plate, 'M' for the major connector, and 'S' for the saddle area. Clinical photograph of a cast metal partial denture framework seated on a pink resin tooth model. Visible components include the retentive clasps engaging the teeth and the connecting bars. # Survey and Design ## The University of Western Australia | Oral Health Centre of Western Australia ### 6) Outline of the framework - **1° Rests** - **2° Grid** - **3° Clasps:** retention arm, reciprocating arm, proximal plate - Supra and infra-bulge - **4° Major connector:** - **Mandibular denture:** 3 – 4 mm from gingival margin and floor of the mouth - **Maxillary denture:** 5 – 6 mm from gingival margin and avoid torus and soft palate   #### Framework Components 1. Rests 2. Grid 3. Clasps: retention arm (supra and infra-bulge), reciprocating arm, and proximal plate #### Major Connector Placement Guidelines - **Mandibular Denture:** Position the connector 3–4 mm away from the gingival margin and the floor of the mouth. - **Maxillary Denture:** Position the connector 5–6 mm away from the gingival margin; ensure the design avoids the torus and the soft palate. Clinical photo showing a mandibular surveyor with the indicator arm placed along the denture framework. The ruler is positioned to demonstrate the distance from the gingival margin and floor of the mouth, corresponding to the 'Mandibular denture: 3 – 4 mm' specification in the text. Clinical photo showing a maxillary surveyor with the indicator arm placed along the denture framework. The ruler demonstrates the vertical position relative to the teeth, illustrating the 'Maxillary denture: 5 – 6 mm from gingival margin' guideline mentioned in the OCR text. **Survey and Design** 6) Outline of the framework 4° Major connector: - 8 mm: Strap – can be thinner, flat - < 8 mm: Bar – need to be bulky    #### Major Connector Dimensions - **Strap:** Used when the width is 8 mm or greater. These can be thinner and flat in profile. - **Bar:** Used when the width is less than 8 mm. These need to be bulky to ensure adequate strength. Clinical photo of a maxillary cast showing a metal framework with major connectors. The image demonstrates the design for an inter-occlusal strap connector in a patient with approximately 8 mm of inter-occlusal space, as indicated by the accompanying text stating '8 mm: Strap – can be thinner, flat'. Clinical photo of a maxillary cast showing a different metal framework design. This image illustrates the design for an inter-occlusal bar connector in a patient with less than 8 mm of inter-occlusal space, consistent with the text '< 8 mm: Bar – need to be bulky'. Schematic diagram illustrating vertical dimension guidelines for a major connector. It depicts teeth and gingival margins with red brackets indicating measurements: 3-4 mm for the distance from the occlusal plane to the gingiva, and 5 mm for the depth of the connector below the gingival margin. A black arrow points downward to indicate the path of insertion or orientation relative to the tissue. # Survey and Design ## 6) Outline of the framework ### 4° Major connector:   4° Major connector: Clinical photo of a dental stone cast showing the left posterior maxilla with a surveyor instrument. Red dotted lines indicate major connector path dimensions: 3 mm at one point and 8 mm at another. Diagram of a maxillary arch with framework outline drawn in black and red dotted lines. Labels indicate spacing measurements (8 mm, 14 mm, 6 mm) for the major connector design around teeth. # **Survey and Design** > **LOGO: THE UNIVERSITY OF WESTERN AUSTRALIA | Or... ## 6) Outline of the framework ### 4° Major connector:  4° Major connector: Labeled diagram of the maxillary arch illustrating a removable partial denture framework. The image displays the outline of the major connector (red line) and clasps engaging abutment teeth on both sides. Contextual text identifies this as '6) Outline of the framework' and '4° Major connector'. Survey and Design 6) Outline of the framework 1° Rests 2° Grid 3° Clasps 4° Major connector 5° Minor connector <b>The University of Western Australia** | **Oral Health Centre of Western Australia**  The framework outline includes the following sequential components: 1. Rests 2. Grid 3. Clasps 4. Major connector 5. Minor connector Labelled diagram of a maxillary partial denture framework. The image displays the anatomical structure of the upper jaw with teeth and gingiva. Overlaid is a black outline representing the metal framework components, including rests (on occlusal surfaces), clasps (engaging tooth contours), major connectors (connecting anterior and posterior sections), minor connectors, and a grid pattern on the palatal surface. The diagram is accompanied by a legend listing: '1° Rests', '2° Grid', '3° Clasps', '4° Major connector', and '5° Minor connector'. Survey and Design **THE UNIVERSITY OF WESTERN AUSTRALIA** Oral Health Centre of Western Australia     Survey and Design Clinical photo of a dental study model showing the lower jaw with survey lines and markings for denture design. Includes zoomed-in inset highlighting specific tooth preparation details. Clinical photo of a dental study model showing the upper jaw with survey lines and markings for denture design. Includes zoomed-in inset highlighting specific tooth preparation details. Clinical photo of a dental study model showing the upper jaw from an occlusal view with survey lines and markings for denture design. Clinical photo of a dental study model showing the lower jaw from an occlusal view with survey lines and markings for denture design. **Survey and Design** 7) Adjust the height of contour and create guiding planes **Aim** All reciprocating arm is above the height of contour 1/3 of the retention arm in undercut  #### Objectives for Adjustment - Ensure the entire reciprocating arm is positioned above the height of contour. - Ensure the terminal one-third of the retention arm is placed within the undercut. Medical illustration demonstrating the adjustment of height of contour and creation of guiding planes. The image displays four views of a tooth with a pink gum base: two showing the tooth surface with a highlighted purple band indicating the 'height of contour', and two showing a metal clasp engaging the tooth. Dotted lines indicate the path of the clasp relative to the height of contour line. **Survey and Design** **7)** Adjust the height of contour and create guiding planes **Modifying height of contour** **Surveyor blade**      #### Tools for Modification - Surveyor blade Diagram illustrating the use of a surveyor blade on a dental cast. The image shows a molar model with an instrument positioned against the buccal surface to trace or adjust the height of contour. Clinical photo showing a dental cast with marked lines indicating the height of contour and guiding planes. Red dashed lines and blue solid lines are drawn along the tooth surface to demonstrate modifications in contour. Photo of a posterior tooth model with multiple colored markings (red vertical lines and blue curved lines) indicating planned adjustments for guiding planes and height of contour modification. Photo showing a tooth model with red vertical reference lines and a blue curved line tracing the path for creating a guiding plane on the occlusal aspect. Close-up procedural photo showing a metal instrument (likely part of a surveyor or bur holder) being used to modify the tooth structure at the margin of a preparation site. White debris is visible around the working area.   Close-up photograph of a dental procedure demonstrating the modification of tooth contour. A white rubber dam is placed over the teeth to isolate the area. A metal dental bur is positioned against the side of a molar tooth. A red arrow points specifically to the contact point between the bur and the tooth surface, indicating where material is being removed or adjusted. Intraoral clinical photograph showing the adjustment of a posterior tooth's height of contour. The view looks into the mouth at two adjacent molars. A dental handpiece with a small, round cutting bur is actively engaged on the proximal surface of the front tooth, removing enamel to create a guiding plane. The surrounding gingival tissue is visible. # Survey and Design ### 7) Adjust the height of contour and create guiding planes **Modifying height of contour**    Modifying height of contour Close-up clinical photo demonstrating the modification of height of contour. A metal surveyor instrument (indicated by a red arrow) is shown touching the buccal surface of a tooth cast to identify or modify the height of contour. Clinical photo showing a prepared tooth with a metallic casting coping in place. The image illustrates the context for adjusting height of contour and creating guiding planes during the survey and design phase of prosthodontics. Clinical photo showing another angle of a prepared tooth with a metallic casting coping. This visual supports the procedure of modifying the height of contour to establish proper guidance for the restoration. **Survey and Design** 7) Adjust the height of contour and create guiding planes **Guiding planes** • The natural bulge of the tooth needs to be flattened by preparation • Provide a single path of **Insertion** (*POI*) • Limits the instability of the RPD • Reduce food impaction **Dentine exposure**   #### Purpose of Guiding Planes - The natural bulge of the tooth needs to be flattened by preparation. - Provide a single path of insertion (POI). - Limits the instability of the RPD. - Reduce food impaction. #### Clinical Considerations - Avoid dentine exposure during preparation. Diagram showing a prepared tooth (center) with flattened height of contour compared to adjacent unprepared teeth. Illustrates the concept of creating guiding planes by flattening natural bulges. Diagram showing an unprepared tooth (center) with natural convexity/height of contour compared to adjacent teeth. Illustrates the pre-preparation state where natural bulges exist before flattening for guiding planes. # Survey and Design ## 7) Adjust the height of contour and create guiding planes ### Proximal Plate ### Clasp Body 2/3 **Intercuspal Distance** 2/3 **crown height**   #### Proximal Plate and Clasp Body Dimensions - 2/3 Intercuspal Distance - 2/3 crown height Labelled diagram titled 'Clasp Body' showing two views of a tooth with a clasp. The left view is a colored cross-section highlighting the clasp components: red (retentive tip), yellow (body), and blue (gingival rest). The right view is a line drawing showing the outline of the clasp in place on the tooth, with red lines indicating the height of contour adjustment level. Clinical photo titled 'Proximal Plate' showing a dental model with a metal proximal plate applied to a molar. Yellow double-headed arrows indicate measurements: one horizontal arrow labeled '2/3 Intercusp Distance' between teeth, and one vertical arrow labeled '2/3 crown height' from the occlusal surface to the start of the plate. Western Australia Oral Health Centre of Western Australia Thank you!  Western Australia Oral Health Centre of Western Australia Thank you! A scenic photograph showing a long wooden pier extending into the turquoise ocean under a clear blue sky. People are walking along the pier on the left side, and a small boat is visible in the water. The image serves as a background visual for the presentation slide. 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