Dr Matsubara <strong>The University of Western Australia</strong> Oral Health Centre of Western Australia **RPD: Components and Classification**  Dr Matsubara Oral Health Centre of Western Australia Clinical photograph of a dental study model demonstrating an RPD (Removable Partial Denture). The image shows a cast with white acrylic base and metallic framework components including clasps and rests on the teeth. <br/> ### LEARNING OUTCOMES </br> * Identify components of an RPD * Discuss the concept of direct and indirect retainer * Classify partially edentulous arches (topography, physiology and biomechanics)  Upon completion of this section, students should be able to: - Identify components of an RPD - Discuss the concept of direct and indirect retainer - Classify partially edentulous arches based on: - Topography - Physiology - Biomechanics A close-up photo of a hand writing on a green chalkboard. The visual serves as an illustrative background for the 'LEARNING OUTCOMES' text listed to the left, which covers identifying components of an RPD (Removable Partial Denture), discussing retainers, and classifying edentulous arches. NEVER  NEVER Educational figure demonstrating dental prosthesis design principles. The main panel shows a top-down view of an upper jaw model with a metal framework and red arrows indicating critical dimensions (width and depth). Two inset panels labeled 'NEVER' show examples of incorrect or contraindicated designs: one depicts a poorly fitted partial denture on a cast, and the other shows a small bridge with inadequate support. **NEVER**      NEVER Clinical photo of a cast showing an ill-fitting removable partial denture with metal clasps. The label 'NEVER' is positioned above this image, indicating that this type of prosthesis or fit should be avoided. Close-up clinical photo of a single-tooth removable partial denture (clasp assembly) featuring a pink acrylic base and a metal retainer/clasp on either side of the artificial tooth. Diagram of a dental cast model demonstrating the fit of a removable partial denture. Red arrows indicate the spatial relationship: one arrow points vertically upwards from the denture to the palate area, and two horizontal arrows point outwards from the sides of the denture towards the molars, likely illustrating clearance or extension requirements. Radiograph (X-ray) showing the skeletal structure of the jaw and teeth, providing context for the placement of dental prosthetics. Clinical photo of a patient holding their throat and grimacing in pain or discomfort, visually representing symptoms like sore throat or dysphagia which may relate to the condition being discussed. # **RPD** ## **THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia** # **COMPONENTS** 1. **Clasp**: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth   #### Removable Partial Denture Components 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Labelled diagram of RPD components on tooth models: left panel shows side view with red (retentive arm), yellow (rest), blue (proximal plate), and brown (saddle); right panel shows occlusal view with same colored regions. Demonstrates spatial relationships between clasp parts. Clinical photo of a removable partial denture (RPD) on a dental cast, highlighting two clasps with red circles — one anteriorly engaging a premolar, the other posteriorly engaging a molar. Shows real-world application of retentive arms and saddle framework. # **RPD** # COMPONENTS 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. **Rest** (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth  1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Clinical photograph of a dental cast demonstrating an RPD (Removable Partial Denture). The image shows the major connector and artificial teeth on a pink base. A red circle highlights the retentive arm engaging with a tooth abutment to demonstrate retention. **RPD** **COMPONENTS** 1. **Clasp:** rest, retentive and reciprocal arms, proximal plate 2. **Rest** (alone) 3. **Major connector** 4. Minor connectors 5. Saddle 6. Artificial teeth  1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Clinical photograph of a removable partial denture (RPD) on a pink dental cast. The image features a silver metal framework with clasp assemblies on the posterior teeth. A large red rectangle highlights the central metallic section spanning the edentulous ridge, which corresponds to the 'Major connector' mentioned in the OCR context. # **RPD** ## **COMPONENTS** 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. **Minor connectors** 5. Saddle 6. Artificial teeth  1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Clinical photograph of a dental cast with an RPD (Removable Partial Denture) framework. The image highlights specific components using red arrows and a red bounding box. A large vertical metal grid structure is highlighted by the red box, corresponding to item '4. Minor connectors' in the text list. Red arrows point to the retentive arm on the left side, the major connector spanning the palate, and the clasp assembly on the right side. **RPD** **COMPO** 1. **Clasp:** rest, retentive and reciprocal arms, proximal plate 2. **Rest (alone)** 3. **Major connector** 4. **Minor connectors** 5. **Saddle** 6. **Artificial teeth** The University of Western Australia | Oral Health Centre of Western Australia    1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Schematic diagram of a dental arch with dotted outlines representing teeth positions. Two sets of blue squares with red outlines highlight specific tooth locations on the left and right sides of the arch, likely indicating abutment teeth or clasp engagement points in an RPD design. Clinical photograph of a lower partial denture (RPD) model showing two red arrows pointing to components: one arrow indicates the metal framework/clasp assembly engaging with natural teeth, and the other points to the pink acrylic saddle area replacing missing teeth. Photograph of an upper partial denture (RPD) model with a red arrow pointing to the metal major connector spanning across the palate. The image shows artificial teeth, metal clasps on adjacent natural teeth, and the overall structure including the saddle and rest areas. **RPD** **COMPONENTS** 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth   1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Clinical photograph of a partial denture demonstrating the 'Rest' component. A red arrow points specifically to the metal rest on one of the artificial teeth, visually illustrating how this part rests against the tooth surface. Clinical photograph showing the complete RPD assembly on a cast. The image displays the major connector spanning the arch and clasps engaging the abutment teeth, providing a visual context for the components listed in the text. **RPD** **** **** **COMPONENTS** 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Direct retainer Indirect retainer **THE UNIVERSITY OF WESTERN AUSTRALIA** | **Oral Health Centre of Western Australia**   #### Structural Elements 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth #### Retention Types - Direct retainer - Indirect retainer Clinical photo of a dental model showing an upper arch with a removable partial denture (RPD) clasp assembly fitted to the posterior teeth. The image provides a close-up view of the metal framework and clasps engaging the abutment teeth. Diagrammatic clinical photo of an RPD on a dental model with specific components highlighted by red annotations. A red circle outlines the 'Direct retainer' area, specifically focusing on the rest and retentive arm engagement on a premolar. A red arrow points upwards from this circled area to indicate the 'Indirect retainer' function located further back in the arch. # RPD ## **COMPONENTS** 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth - Direct retainer - Indirect retainer [Image of a removable partial denture model with labeled parts including a clasp assembly, major connector, and minor connector circle]  #### Structural Elements 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth #### Retention Types - Direct retainer - Indirect retainer Clinical photograph of a removable partial denture (RPD) model with labeled functional components. The image displays a pink acrylic base with artificial teeth and metal framework. Annotations include: a yellow curved arrow indicating the 'Direct retainer' clasp assembly on the left; a red vertical arrow pointing to the 'Major connector' in the center; and a red circle highlighting the 'Indirect retainer' mechanism on the right. **RPD** # COMPONENTS 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Direct retainer Indirect retainer  #### Structural Elements 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth #### Retention Types - Direct retainer - Indirect retainer Clinical photograph of a maxillary removable partial denture (RPD) on a cast. The image highlights specific components with annotations: red circles indicate the 'Direct retainer' clasp assembly engaging the abutment teeth; a yellow curved arrow indicates the path of insertion/removal for the 'Indirect retainer'; and a red arrow points to the metal framework in the posterior region. **RPD** **COMPONENTS** 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. **Rest (alone)** 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth Direct retainer Indirect retainer  #### Structural Elements 1. Clasp: rest, retentive and reciprocal arms, proximal plate 2. Rest (alone) 3. Major connector 4. Minor connectors 5. Saddle 6. Artificial teeth #### Retention Types - Direct retainer - Indirect retainer Clinical photograph of a removable partial denture (RPD) on a dental cast. The image is annotated with visual overlays to identify key components: a red arrow points to the 'Direct retainer' (clasp assembly), a yellow curved arrow indicates the rotational axis of the saddle, and a red circle highlights the 'Indirect retainer' (rest). A diagonal red line demarcates the functional plane. **RPD** **The University of Western Australia** **Oral Health Centre of Western Australia** **CLASSIFICATION OF PARTIALLY EDENTUOUS ARCHES** **Importance:** • Communication between professionals • Didactic • Standardization of treatment planning • Visualize the difficulty of each case The classification of partially edentulous arches is essential for several reasons: - Communication between professionals - Didactic purposes - Standardization of treatment planning - Visualization of the difficulty of each case # RPD ## Classification of Partially Edentulous Arches **Classification should:** * Allow the visualization of edentulous areas * Give information about the type of support * Characterize where the alveolar bone will receive occlusal forces * Universally accepted An effective classification system should: - Allow the visualization of edentulous areas - Give information about the type of support - Characterize where the alveolar bone will receive occlusal forces - Be universally accepted **RPD** The University of Western Australia | Oral Health Centre of Western Australia ## CLASSIFICATION ### Basis for Classification * **Topographic** - Quantity and location of edentulous spaces * **Physiological** - How the bone will receive the masticatory load * **Biomechanics** - Position of direct retainers and the need for indirect retainers  #### Classification Criteria - **Topographic**: Based on the quantity and location of edentulous spaces. - **Physiological**: Based on how the bone will receive the masticatory load. - **Biomechanics**: Based on the position of direct retainers and the need for indirect retainers. Educational slide from The University of Western Australia Oral Health Centre titled 'RPD CLASSIFICATION'. It presents a structured diagram or outline defining the three main bases for classifying Removable Partial Dentures (RPDs): Topographic (focusing on edentulous spaces), Physiological (focusing on masticatory load reception by bone), and Biomechanics (focusing on retainer positioning). # CLASSIFICATION OF RPD • Cummer (1920) devised the first classification based on position and number of direct retainer and position of indirect retainer • **Edward Kennedy (1925)** • Bailyn (1928) • Neurohr’s Classification (1939) - based on the support derived. • Godfrey (1951) – based on the location and size of edentulous spaces • Beckett (1953) • Friedman (1953) – ABC classification - A: Anterior, B: Bounded posterior, C: Cantilever • **Applegate-Kennedy (1954) – modification of Kennedy’s system** • Skinner (1959) – influenced by Cummer’s classification • Swenson (1963) Various systems have been developed to categorize partially edentulous arches: - **Cummer (1920)**: Devised the first classification based on the position and number of direct retainers and the position of indirect retainers. - **Edward Kennedy (1925)** - **Bailyn (1928)** - **Neurohr (1939)**: Based on the support derived. - **Godfrey (1951)**: Based on the location and size of edentulous spaces. - **Beckett (1953)** - **Friedman (1953)**: ABC classification (A: Anterior, B: Bounded posterior, C: Cantilever). - **Applegate-Kennedy (1954)**: A modification of Kennedy’s system. - **Skinner (1959)**: Influenced by Cummer’s classification. - **Swenson (1963)** RPD **CLASSIFICATION** Kennedy classification • Relates the edentulous area and the remaining teeth • Does not take into account the number of missing teeth • 4 groups: - Class I - Class II - Class III - Class IV The Kennedy classification system: - Relates the edentulous area and the remaining teeth. - Does not take into account the number of missing teeth. - Consists of 4 groups: Class I, Class II, Class III, and Class IV. RPD **CLASSIFICATION** Kennedy classification **Class I:** **Bilateral** distal edentulous areas **The University of** **WESTERN** **AUSTRALIA** Oral Health Centre of Western Australia  Class I is defined by bilateral distal edentulous areas. Clinical photograph of a maxillary (upper) Removable Partial Denture (RPD) demonstrating the Kennedy Class I classification. The denture features bilateral distal edentulous areas, indicated by the absence of posterior teeth at both ends of the arch while retaining anterior and premolar teeth. The image shows the acrylic base with artificial teeth set in place. **RPD** The University of Western Australia | Oral Health Centre of Western Australia **CLASSIFICATION** Kennedy classification **Class II:** Unilateral distal edentulous areas  Class II is defined by unilateral distal edentulous areas. Clinical photo of a maxillary removable partial denture (RPD) base. The image displays the tissue-side view of the appliance with pink acrylic flanges. On the left side, natural teeth are present, while the right side shows three distinct edentulous areas (tooth sockets), illustrating the 'Unilateral distal edentulous areas' characteristic of a Kennedy Class II classification. **RPD** **CLASSIFICATION** Kennedy classification Class III: **Unilateral** edentulous area with teeth anterior and posterior to the edentulous area  Class III is defined by a unilateral edentulous area with teeth remaining both anterior and posterior to the space. Clinical photograph of a maxillary (upper) dental cast demonstrating Kennedy Class III classification. The image shows a unilateral edentulous area on the left side of the arch where several posterior teeth are missing, while remaining natural teeth are present both anteriorly and posteriorly to the gap, matching the definition provided in the text. **RPD** THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia **CLASSIFICATION** Kennedy classification Class IV: Anterior edentulous area crossing the midline  Class IV is defined by a single anterior edentulous area that crosses the midline. Educational diagram illustrating the Kennedy classification for Class IV: Anterior edentulous area crossing the midline. The image displays two views of a dental arch: the left side shows a full set of posterior teeth with a curved line indicating the span across the anterior region; the right side shows only the posterior teeth with a wide gap in the center representing the missing anterior teeth. This visual demonstrates the specific condition where the tooth loss extends from one side to the other, crossing the midline. # RPD **THE UNIVERSITY OF WESTERN AUSTRALIA** **Oral Health Centre** **of Western Australia** ## CLASSIFICATION Kennedy classification ## MODIFICATIONS * Each additional edentulous area (not each missing teeth) is referred as a modification space. * Include the number of modification areas in the classification  #### Defining Modifications - Each additional edentulous area (not each individual missing tooth) is referred to as a modification space. - The number of modification areas must be included in the final classification. Line diagram of a dental arch illustrating the Kennedy Classification for Removable Partial Dentures (RPD). The drawing shows an upper jaw with missing teeth in the posterior regions on both sides. Specifically, it depicts a bilateral distal extension case where the remaining natural teeth are anterior to the edentulous areas, characteristic of a Class I modification scenario. RPD **CLASSIFICATION** Kennedy classification MODIFICATIONS Class II, Modification 2 Class II, Modification 1   Examples of modifications include: - Class II, Modification 1 - Class II, Modification 2 Diagram of a maxillary arch showing a Class II, Modification 2 Kennedy classification. The diagram illustrates a unilateral posterior tooth loss on the right side with an extension to the distal of the remaining teeth and a clasp arm extending from the distal abutment towards the edentulous area. Diagram of a maxillary arch showing a Class II, Modification 1 Kennedy classification. The diagram illustrates a bilateral posterior tooth loss with a saddle area in the center and clasps extending from both sides towards the edentulous area. # Kennedy classification ## APPLEGATE'S RULES 1. The classification should be determined after all extractions (if applicable) 2. If the third molar is missing and is not to be replaced, it is not considered in the classification **Class III**  1. The classification should be determined after all extractions (if applicable). 2. If the third molar is missing and is not to be replaced, it is not considered in the classification. Example: Class III A schematic diagram illustrating a Class III Kennedy classification for partial dentures. The image depicts a dental arch represented by colored blocks: blue blocks indicate existing posterior teeth, yellow blocks represent anterior teeth, and red blocks signify remaining molars. A gap in the posterior section is marked with dotted outlines and a large red 'X', indicating missing third molars that are not to be replaced according to Applegate's Rules. The label 'Class III' identifies the specific classification shown. # RPD CLASSIFICATION Kennedy classification APPLEGATE'S RULES 1. The classification should be determined after all extractions (if applicable) 2. If the third molar is missing and is not to be replaced, it is not considered in the classification 3. If the third molar is present and is an abutment, it is considered in the classification Class III  1. The classification should be determined after all extractions (if applicable). 2. If the third molar is missing and is not to be replaced, it is not considered in the classification. 3. If the third molar is present and is an abutment, it is considered in the classification. Example: Class III Labeled dental arch diagram illustrating Kennedy Class III classification. The visual structure consists of a curved arrangement of tooth-like blocks: yellow blocks at the anterior (top), red and orange blocks on the lateral sides, and blue blocks at the posterior ends. Dotted outlines indicate missing teeth in the left posterior region. The label 'Class III' is positioned to the right of the diagram. # **RPD** **CLASSIFICATION** Kennedy classification APPLEGATE'S RULES 1. The classification should be determined after all extractions (if applicable) 2. If the third molar is missing and is not to be replaced, it is not considered in the classification 3. If the third molar is present and is an abutment, it is considered in the classification 4. If the second molar is missing and is not to be replaced, it is not considered in the classification 5. The most posterior edentulous area(s) always determines the classification **CLASSIFICATION** **Modification** Class II Mod 1  1. The classification should be determined after all extractions (if applicable). 2. If the third molar is missing and is not to be replaced, it is not considered in the classification. 3. If the third molar is present and is an abutment, it is considered in the classification. 4. If the second molar is missing and is not to be replaced, it is not considered in the classification. 5. The most posterior edentulous area(s) always determines the classification. Example: Class II Mod 1 Labeled schematic diagram illustrating Kennedy Classification and Applegate's Rules for RPD. The image depicts a dental arch with specific tooth positions. Red arrows indicate key areas: one pointing to the posterior edentulous space labeled 'Classification', and another pointing to an adjacent area labeled 'Modification'. Text on the right identifies the scenario as 'Class II Mod 1'. # RPD | **THE UNIVERSITY OF WESTERN AUSTRALIA** | Oral Health Centre of Western Australia | | :--- | :--- | # CLASSIFICATION ## Kennedy classification ### APPLEGATE'S RULES 6. Edentulous areas other than those determining the classification are referred as "modification" and are designated by their number 7. The extent of the mod is not considered, only the number of additional edentulous areas 8. There is no modification in Class IV   6. Edentulous areas other than those determining the classification are referred to as "modifications" and are designated by their number. 7. The extent of the modification is not considered, only the number of additional edentulous areas. 8. There is no modification in Class IV. Schematic diagram of a dental arch representing Kennedy Classification Rule 8 (No modification in Class IV). The arch contains two continuous edentulous areas at the posterior segments (highlighted in red and yellow blocks), which constitute the primary classification. There are no additional isolated edentulous spaces elsewhere on the arch, visually confirming that this configuration does not require a 'modification' designation. Schematic diagram illustrating Applegate's Rule 6 and 7 (Modifications). This visual shows an arch with a primary edentulous area classified as Class II (red block). Additionally, there are two distinct, separate edentulous areas located anteriorly to the main gap (outlined in dotted lines). These represent the 'additional edentulous areas' mentioned in the text, resulting in the classification label 'Class II, Modification 2' displayed below. # **RPD** ## **CLASSIFICATION** Kennedy classification APPLEGATE’S MODIFICATION Suggested two additional classifications – Classes V and VI These are a variation of Kennedy’s original Class III, because three completely different clinical situations could exist, each requiring a different design consideration ### Class V Similar to class III but large edentulous space, anterior tooth is weak and unable to support a clasp assembly, e.g. lateral incisor ### Class VI Similar to class III but abutment teeth much stronger, short edentulous area – this class can possibly be treated with a fixed prosthesis   Applegate suggested two additional classifications—Classes V and VI—as variations of Kennedy’s original Class III. These represent different clinical situations requiring specific design considerations. #### Class V Similar to Class III but involves a large edentulous space where the anterior abutment tooth (e.g., lateral incisor) is weak and unable to support a clasp assembly. #### Class VI Similar to Class III but the abutment teeth are much stronger and the edentulous area is short. This class can potentially be treated with a fixed prosthesis. Labeled diagram of a dental arch showing Kennedy Class V edentulous area. The image depicts the upper jaw with missing teeth in the anterior region and a large gap extending posteriorly. A large 'V' is superimposed over the edentulous space to indicate the classification. Labeled diagram of a dental arch showing Kennedy Class VI edentulous area. The image depicts the upper jaw with missing teeth in the anterior region and a short gap between two abutment teeth. A large 'VI' is superimposed over the edentulous space to indicate the classification. **RPD** ### CLASSIFICATION Classification according to type of support 1) Tooth supported (Tooth-borne RPD) * Load transmitted to the remaining teeth (Periodontium) * Traction stimuli * No occlusal load on the alveolar ridge mucosa <b>RPD</b> **CLASSIFICATION** Classification according to type of support 1) Tooth supported (Tooth-borne RPD) * Load transmitted to the remaining teeth (Periodontium) * Traction stimuli * No occlusal load on the alveolar ridge mucosa  #### 1) Tooth Supported (Tooth-borne RPD) - Load is transmitted to the remaining teeth via the periodontium. - Results in traction stimuli. - No occlusal load is placed on the alveolar ridge mucosa. Diagram illustrating a tooth-borne RPD (Removable Partial Denture) classification. It shows two arches of teeth represented by colored squares: yellow for natural teeth, red for abutment teeth, and blue for denture bases. The diagram highlights the load transmission to the remaining teeth (periodontium) through traction stimuli, with no occlusal load on the alveolar ridge mucosa. **RPD** **CLASSIFICATION** Classification according to type of support 2) Tooth and tissue supported (Tooth and tissue-borne RPD) A) * Load transmitted to the remaining teeth and mucosa * Greater transmission through the teeth   #### 2) Tooth and Tissue Supported (Tooth and tissue-borne RPD) **Category A:** - Load is transmitted to both the remaining teeth and the mucosa. - There is a greater transmission of force through the teeth. Diagram of a dental arch representing a tooth and tissue-supported RPD. The arch contains colored squares (red, yellow, blue) and empty squares. Red squares are located at the posterior ends of the arch (molars), yellow squares are adjacent to them, and blue squares are positioned anteriorly near the midline or canine region. Empty squares represent edentulous spaces. This visual corresponds to the text 'Load transmitted to the remaining teeth and mucosa' and 'Greater transmission through the teeth', illustrating how forces are distributed in this classification. Diagram of a dental arch similar to the one above, also illustrating a tooth and tissue-supported RPD. It features red squares at the posterior, yellow squares next to them, and a blue square on the right side anterior to the molars. An empty square is visible on the far right. This diagram serves as a second example or variation of the same concept described in section A). RPD **CLASSIFICATION** **Classification according to type of support** 2) **Tooth and tissue supported (Tooth and tissue borne RPD)** B) * **Loading transmitted mainly to the mucosa**   #### 2) Tooth and Tissue Supported (Tooth and tissue-borne RPD) **Category B:** - Loading is transmitted mainly to the mucosa. Schematic diagram illustrating a 'Tooth and tissue supported' RPD arch. The upper portion of the dental arch is highlighted with solid red and yellow blocks representing teeth providing support, while the lower and central portions are outlined in dotted lines indicating tissue-supported areas. Schematic diagram illustrating an alternative loading distribution for a 'Tooth and tissue supported' RPD. This visual shows the load transmitted mainly to the mucosa, indicated by solid blue blocks at the distal ends of the arch (representing rest seats), with the majority of the arch remaining as dotted outlines. # RPD **THE UNIVERSITY OF WESTERN AUSTRALIA** **Oral Health Centre of Western Australia ## CLASSIFICATION **Classification according to type of support** 3) Tissue supported (Tissue borne complete denture) * Loading transmitted to the mucosa #### 3) Tissue Supported (Tissue-borne complete denture) - Loading is transmitted entirely to the mucosa. **RPD** **The University of Western Australia** **Oral Health Centre of Western Australia** # CLASSIFICATION **Biomechanics** * Possible movements of the RPD * Presence of lever arms **INTERCALATED** **LEVERED** **COMBINED** Biomechanics considerations include: - Possible movements of the RPD - Presence of lever arms Classification types: - **INTERCALATED** - **LEVERED** - **COMBINED** # **RPD** ```html <table> <tr> <th>THE UNIVERSITY OF</th> <td>Oral Health Centre</td> <td>of Western Australia</td> </tr> <tr> <th>WESTERN</th> <td></td> <td></td> </tr> <tr> <th>AUSTRALIA</th> <td></td> <td></td> </tr> </table> ``` ## **CLASSIFICATION** ### **Biomechanics** ### **INTERCALATED** - Edentulous area limited by teeth - No free end saddles  #### INTERCALATED - The edentulous area is limited by teeth on both sides. - There are no free-end saddles. Clinical photograph of an intercalated removable partial denture (RPD) in the maxillary arch. The image shows a pink acrylic base with artificial teeth, where the edentulous area is limited by natural teeth on both sides and there are no free end saddles, as described in the OCR text. **RPD** **THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia** **CLASSIFICATION** Biomechanics LEVERED • Free end edentulous area   #### LEVERED - Characterized by a free-end edentulous area. Clinical photograph of an upper maxillary Removable Partial Denture (RPD). The denture features a pink acrylic base with artificial teeth. It is designed for a 'free end edentulous area' as indicated by the text on the slide. Two metal wires cross over the denture to demonstrate the levered biomechanical action associated with this classification. Clinical photograph of a second upper maxillary Removable Partial Denture (RPD), also labeled 'JRM'. This image appears to be part of the same comparison set demonstrating RPD classification and biomechanics, specifically focusing on free-end saddle designs. RPD **The University of Western Australia** **Oral Health Centre of Western Australia** CLASSIFICATION Biomechanics COMBINED • Intercalated and free end edentulous area  #### COMBINED - Features both intercalated and free-end edentulous areas. Schematic line drawing of a dental arch illustrating a 'COMBINED' classification in RPD biomechanics. The diagram shows an upper jaw with multiple teeth remaining on the anterior and right posterior sides, while the left side depicts missing teeth (edentulous area). A vertical connector is drawn to represent a bridge spanning the gap between the remaining teeth, indicating an intercalated edentulous area. 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