Title slide for a presentation on 'Fixed Partial Prosthesis: Classification and clinical rationale'. The slide includes the logos of The University of Western Australia and the Oral Health Centre of Western Australia at the top. At the bottom right, there is an acknowledgement to Dr Matsubara. **Learning outcomes** * Understand and discuss the advantages and disadvantages of different types of FPD * Discuss the differences between the types of bridges * Discuss tooth preparation for bonded bridges * Discuss fibre-reinforced bonded bridges * Discuss the concept of Shortened dental arch * Discuss the clinical rationale of prosthetic treatment using FPD: factors that affect the prognosis of the treatment Reading: Practical advice for successful clinical treatment with resin-bonded bridges Stephanie King,1 Banoo Sood1 and Martin P. Ashley2 THE UNIVERSITY OF WESTERN AUSTRALIA  #### Core Competencies - Understand and discuss the advantages and disadvantages of different types of Fixed Partial Dentures (FPD) - Discuss the differences between the types of bridges - Discuss tooth preparation for bonded bridges - Discuss fibre-reinforced bonded bridges - Discuss the concept of the Shortened Dental Arch - Discuss the clinical rationale of prosthetic treatment using FPD, including factors that affect the prognosis of the treatment #### Recommended Reading - *Practical advice for successful clinical treatment with resin-bonded bridges* by Stephanie King, Banoo Sood, and Martin P. Ashley University logo for 'THE UNIVERSITY OF WESTERN AUSTRALIA' with a crest and text. It serves as an institutional identifier on the slide. **Classification** **PROSTHODONTICS** The University of Western Australia | Oral Health Centre of Western Australia | **Dental Prosthodontics** ✗ **Maxillofacial Prosthodontics** | |---|---|---| | **Fixed Dental Prostheses** | **Removable Dental Prostheses** | |---|---|---| | **Tooth supported (crown & bridge)** <br> - Cement-retained <br> - Resin-bonded | **Partial** <br> | | **Implant supported (crown & bridge)** <br> - Screw-retained <br> - Cemented | **Complete** | Label **Classification**  #### Classification of Dental Prosthodontics - **Fixed Dental Prostheses** - Tooth supported (crown & bridge) - Cement-retained - Resin-bonded - Implant supported (crown & bridge) - Screw-retained - Cemented - **Removable Dental Prostheses** - Partial - Complete Classification diagram of Prosthodontics. The chart branches from the main category 'Dental Prosthodontics' (blue box) into two sub-categories: 'Fixed Dental Prostheses' and 'Removable Dental Prostheses' (yellow boxes). Under Fixed Dental Prostheses, it lists 'Tooth supported (crown & bridge)' with subtypes 'Cement-retained' and 'Resin-bonded', and 'Implant supported (crown & bridge)' with subtypes 'Screw-retained' and 'Cemented'. Under Removable Dental Prostheses, it lists 'Partial' and 'Complete'. A separate branch for 'Maxillofacial Prosthodontics' is shown in a blue box. **Classification** Image displaying dental bridges with visible metal, porcelain-fused-to-metal, all-ceramic, and resin components. **Material** * Acrylic, composite (temporary bridge) * Cast metal: gold alloy * Metal-ceramic (PFM) * Resin-Veneered * All ceramic (e.g. zirconia)      #### Material Options - Acrylic, composite (temporary bridge) - Cast metal: gold alloy - Metal-ceramic (PFM) - Resin-Veneered - All ceramic (e.g. zirconia) Clinical photo of a dental arch showing a metal-ceramic (PFM) bridge. The image demonstrates the visible dark metal substructure of the prosthetic teeth contrasting with natural adjacent teeth. Clinical photo of an all-ceramic dental bridge in situ. The restoration shows a uniform tooth-colored appearance without visible metal components. Photo of a Metal-Ceramic (PFM) bridge displayed against a blue background. The image clearly illustrates the dark grey metallic framework underneath the porcelain veneers. Clinical photo of an all-ceramic bridge installed on the upper anterior teeth. The restoration presents a seamless, opaque white aesthetic matching the surrounding dentition. Photo of a resin-veneered or acrylic temporary bridge shown isolated on a cloth surface. This visual demonstrates the material properties and form of a non-metal provisional restoration. Classification **Cement-Retained FPD** Metal-ceramic All ceramic * Cemented with conventional luting material (GIC, RMGIC, Zinc phosphate) * Cemented with conventional luting material * Bonded with resin cement   #### Cementation Methods - **Metal-ceramic** - Cemented with conventional luting material (GIC, RMGIC, Zinc phosphate) - **All ceramic** - Cemented with conventional luting material - Bonded with resin cement Clinical photo of a metal-ceramic Cement-Retained FPD showing the metallic substructure and ceramic veneer. Caption indicates it is cemented with conventional luting material (GIC, RMGIC, Zinc phosphate). Clinical photo of an all-ceramic Cement-Retained FPD showing a tooth-shaped prosthesis without visible metal. Caption indicates it is bonded with resin cement. **Classification** **Resin-bonded FPD** Early bonded FPD Extracted natural teeth Acrylic teeth (temporary restoration) Etched cast 70s - Rochette bridge Maryland Bridge      #### Evolution of Resin-Bonded FPD - Early bonded FPD - Extracted natural teeth - Acrylic teeth (temporary restoration) - Etched cast - 70s - Rochette bridge - Maryland Bridge Clinical photo showing early bonded FPD temporary restoration using extracted natural teeth and acrylic teeth. Photo of an etched cast for resin-bonded FPD preparation. Photo of a 70s Rochette bridge showing metal framework with acrylic teeth. Photo showing the occlusal view of a Rochette bridge on a dental cast model. Clinical photo of a Maryland Bridge showing metal wings bonded to adjacent teeth. # Classification Resin-bonded FPD Traditional approach ## **ADVANTAGES** * Minimal removal of tooth structure (wing thickness 0.8mm) * Supragingival preparation, easy impression making * Interim restoration not usually required  #### Traditional Approach Advantages - Minimal removal of tooth structure (wing thickness 0.8mm) - Supragingival preparation, easy impression making - Interim restoration not usually required Institutional logo block featuring the University of Western Australia crest and name alongside the Oral Health Centre of Western Australia logo. # Classification **The University of Western Australia** Oral Health Centre of Western Australia ## Resin-bonded FPD Traditional approach ### **ADVANTAGES** * Minimal removal of tooth structure * Supragingival preparation, easy impression making * Interim restoration not usually required ### **DISADVANTAGES** * Reduced restoration longevity * Space correction is limited * Good alignment of abutment teeth is required * Esthetics is compromised on anterior  #### Traditional Approach Overview ##### Advantages - Minimal removal of tooth structure - Supragingival preparation, easy impression making - Interim restoration not usually required ##### Disadvantages - Reduced restoration longevity - Space correction is limited - Good alignment of abutment teeth is required - Esthetics is compromised on anterior Clinical photo of a traditional resin-bonded Fixed Partial Denture (FPD) restoration. The image shows the posterior teeth with metal crowns on the abutment teeth and a pontic in between, demonstrating the 'Traditional approach' mentioned in the text. **Classification** Resin-bonded FPD Traditional approach **INDICATIONS** • Short edentulous space (one tooth) • Healthy/Unrestored abutments (enamel surface) • Significant clinical crown length • Temporary restoration - space maintenance • Open bite #### Clinical Indications - Short edentulous space (one tooth) - Healthy/Unrestored abutments (enamel surface) - Significant clinical crown length - Temporary restoration - space maintenance - Open bite # Classification ## Resin-bonded FPD *Traditional approach* **INDICATIONS** * Short edentulous space (one tooth) * Healthy/Unrestored abutments (enamel surface) * Significant clinical crown length * Temporary restoration - space maintenance * Open bite **CONTRAINDICATIONS** * Damaged abutments * Large edentulous area * Unfavorable angulation and rotation of abutments * Parafunctional habits or heavy occlusal forces * Deep bite * Mobile teeth * Alloy allergy #### Traditional Approach Criteria ##### Indications - Short edentulous space (one tooth) - Healthy/Unrestored abutments (enamel surface) - Significant clinical crown length - Temporary restoration - space maintenance - Open bite ##### Contraindications - Damaged abutments - Large edentulous area - Unfavorable angulation and rotation of abutments - Parafunctional habits or heavy occlusal forces - Deep bite - Mobile teeth - Alloy allergy The University Westernof Australia THEAUSTRALIA Oral Health Centre of Western Australia # Classification Resin-bonded FPD Traditional approach ## Design and construction: * Cantilevered design (anterior) Survival characteristics of 771 resin-retained bridges provided at a UK dental teaching hospital Research | Published: 10 April 2015 **P. A. King, L. V. Foster,** R. J. Yates, **R. G. Newcombe & M. J. Garrett** Figure 3 3es  #### Design and Construction - Cantilevered design (anterior) *Reference: Survival characteristics of 771 resin-retained bridges provided at a UK dental teaching hospital. King, Foster, Yates, Newcombe & Garrett (2015).* Cumulative survival curve chart (Figure 3) comparing 'Cantilever' and 'Others' resin-bonded FPD designs. X-axis: Time to failure or censoring (0.00–15.00). Y-axis: Cum Survival (0.0–1.0). Legend includes censored data points for both groups. The Cantilever line remains higher than the Others line throughout the period, indicating better survival. Caption below states: 'Survival curves for 476 cantilever bridges and a group comprising 292 fixed-fixed and yes'. **Resin-bonded FPD** **Metal-ceramic** **Stability** & **Retention** **Single path of Insertion**    #### Metal-Ceramic Stability - Stability and Retention - Single path of Insertion Anatomical diagram illustrating the 'Single path of Insertion' for a Resin-bonded FPD. The drawing shows a tooth preparation with red arrows indicating the vertical insertion path into the retentive grooves on the lingual surface of the abutment teeth. Clinical intraoral photograph showing the placement of a metal-ceramic Resin-bonded FPD. The image highlights the metal framework bonded to the lingual surfaces of the abutment teeth, demonstrating the 'Stability & Retention' mechanism described in the text. A clinical model or cast showing two anterior teeth with superimposed diagrams outlining the preparation design. Red shaded areas indicate the bonding surfaces and retention features (likely grooves) required for the resin-bonded FPD. # Resin-bonded FPD Metal-ceramic **Guide planes**: maximum surface area of enamel contact, POI, Resistance against horizontal movement **Axial grooves** Resistance against horizontal movement **Rest seat** Resistance against vertical occlusal forces    #### Structural Components - **Guide planes**: maximum surface area of enamel contact, POI, Resistance against horizontal movement - **Axial grooves**: Resistance against horizontal movement - **Rest seat**: Resistance against vertical occlusal forces Clinical photo showing a tooth preparation with a dental bur creating a guide plane on the enamel surface. The text 'Guide planes: maximum surface area of enamel contact, POI, Resistance against horizontal movement' describes this step. Procedure image showing axial grooves being prepared on a tooth using a dental bur. The text 'Axial grooves: Resistance against horizontal movement' explains the function of this feature. Procedure image demonstrating the creation of a rest seat on the occlusal surface of a tooth. The text 'Rest seat: Resistance against vertical occlusal forces' describes its purpose. Resin-bonded FPD Metal-ceramic **THE UNIVERSITY OF WESTERN AUSTRALIA** Oral Health Centre of Western Australia   Resin-bonded FPD Metal-ceramic Clinical photo showing a dental preparation for a resin-bonded FPD (metal-ceramic). The image displays two adjacent posterior teeth with visible markings and red outlines indicating the extent of the tooth reduction. The left tooth shows a partial crown preparation outline, while the right tooth has more extensive outlining on its buccal surface. Clinical photo showing another view or stage of the same dental preparation for a resin-bonded FPD (metal-ceramic). Similar to the previous image, this one also features two posterior teeth with red outlines marking the prepared areas. The left tooth shows a broader outlined area compared to the first image, suggesting different stages or perspectives of the preparation process. Resin-bonded FPD Metal-ceramic The University of WESTERN AUSTRALIA Oral Health Centre of Western Australia   Resin-bonded FPD Metal-ceramic Clinical photo showing the anterior maxillary dentition with a missing central incisor (likely tooth #9 or #10). The adjacent teeth are visible, and the gingival tissue appears healthy. This image demonstrates the pre-treatment condition relevant to the 'Resin-bonded FPD' context. Procedure image demonstrating the preparation of a tooth for a metal-ceramic resin-bonded fixed partial denture (FPD). A dental bur is actively cutting into the labial surface of a lateral incisor, while black marking lines outline the prepared area on both the abutment tooth and the pontic site. This illustrates the clinical step of tooth reduction required for the restoration. Resin-bonded FPD Metal-ceramic <p style="text-align:right;"> **THE UNIVERSITY OF** **WESTERN** **AUSTRALIA** Oral Health Centre of Western Australia </p>  Resin-bonded FPD Metal-ceramic Clinical procedure images demonstrating the preparation of teeth for a Resin-bonded FPD (Metal-ceramic). The left panel shows an intraoral view with a dental drill actively preparing the lingual surface of a tooth, alongside adjacent teeth marked with pencil guidelines. The right panel displays two prepared abutment teeth with visible metal retentive wings and pencil outlines, illustrating the final stage before cementation. Resin-bonded FPD Metal-ceramic **THE UNIVERSITY OF WESTERN AUSTRALIA** **Oral Health Centre of Western Australia**     Resin-bonded FPD Metal-ceramic Clinical procedure image showing the preparation of a resin-bonded FPD metal-ceramic. A dental bur is actively cutting into a tooth marked with black outlines, indicating the margin for the restoration. Clinical procedure image showing the same tooth as in the previous image but without the active cutting, displaying the prepared margin clearly outlined in black. Photo of a prepared tooth against a black background, likely demonstrating the final shape or fit of the metal-ceramic restoration. Clinical procedure image showing another angle of the tooth preparation process, with a dental bur cutting into the tooth and black outlines marking the margin. # Resin-bonded FPD Metal-ceramic THE UNIVERSITY OF WESTERN AUSTRALIA   Metal-ceramic Clinical photo showing two prepared teeth for a resin-bonded FPD. The enamel has been reduced and etched, revealing the underlying dentin structure outlined with a marker or guide. Clinical photo of the same teeth after placement of metal-ceramic crowns. The crowns are bonded to the prepared teeth, demonstrating the final restoration. Resin-bonded FPD ALL CERAMIC THE UNIVERSITY OF WESTERN AUSTRALIA Oral Health Centre of Western Australia   Resin-bonded FPD ALL CERAMIC Clinical photo of the occlusal view of maxillary anterior teeth showing a resin-bonded FPD with all-ceramic crowns. The image displays the prepared tooth structure and the ceramic restoration on the lingual surface. Clinical photo of the frontal view of maxillary anterior teeth showing a resin-bonded FPD with all-ceramic crowns. The image displays the esthetic appearance of the restored teeth in relation to the adjacent natural dentition. Resin-bonded FPD All ceramic The University of Western Australia | Oral Health Centre of Western Australia    Resin-bonded FPD All ceramic Clinical photo of a dental model showing an all-ceramic resin-bonded FPD (Fixed Partial Denture) in the upper anterior region. The image displays the pontic and retainer teeth with visible margins. Clinical photo of a dental model showing an all-ceramic resin-bonded FPD in the lower anterior region. The image highlights the pontic and retainer teeth with visible margins. Clinical photo of an all-ceramic resin-bonded FPD in situ on a patient's upper anterior teeth. The image shows the pontic and retainer teeth with healthy gingival tissue. # Resin-bonded FPD ## PRINCIPLES OF Tooth PREPARATION Intra-enamel preparation Supragingival margins Maximize surface area for retainers Bracing of abutments Single path of insertion Clearance for retainers Rest seats  #### Preparation Guidelines - Intra-enamel preparation - Supragingival margins - Maximize surface area for retainers - Bracing of abutments - Single path of insertion - Clearance for retainers - Rest seats Diagram illustrating the 'Intra-enamel preparation' principle for a resin-bonded FPD. It shows a cross-section of a tooth with a blue shaded area representing the prepared enamel surface and a red line indicating the margin or path of insertion.    Clinical photo of a dental arch showing multiple teeth with existing restorations. The central tooth has a dark, possibly amalgam or composite filling. Adjacent teeth show signs of wear or previous treatments. Close-up clinical photo of two adjacent molars. The left molar shows significant occlusal wear and discoloration, while the right molar appears intact with natural tooth structure. Clinical photo focusing on two posterior teeth. The left tooth exhibits normal anatomy, while the right tooth has a visible restoration, likely an inlay or onlay, indicated by the text label 'Retainers: Inlay Onlay' nearby.   Clinical close-up photograph of a dental resin-bonded Fixed Partial Denture (FPD) on the occlusal surface. The image displays an all-ceramic bridge connecting three molar teeth, showing the natural anatomical contours and occlusal anatomy of the prosthetic restoration. Clinical close-up photograph of a dental resin-bonded FPD from a different angle or view. It shows the all-ceramic bridge connecting adjacent posterior teeth, highlighting the fit and surface texture of the ceramic material within the oral cavity. **Resin-bonded FPD** **All ceramic** Pegoraro et al 2013   Resin-bonded FPD All ceramic *Reference: Pegoraro et al 2013* Clinical photograph of a resin-bonded fixed partial denture (FPD), all ceramic. The image shows the occlusal surface of the bridge with two pontics and two abutment crowns, displayed against a white background. Intraoral clinical photograph showing the same resin-bonded FPD installed in the patient's mouth. The restoration is visible between natural teeth, demonstrating fit and contour within the oral cavity. Resin-bonded FPD **Fiber-reinforced** Fiber-reinforced bonded bridge: natural or acrylic tooth **everStick 2Net** **everStick Ortho** **everStick Post** **everStick C&B**        #### Fiber-Reinforced Materials - Fiber-reinforced bonded bridge: natural or acrylic tooth - **Product variants:** - everStick 2Net - everStick Ortho - everStick Post - everStick C&B Clinical photo showing a resin-bonded fiber-reinforced bridge being manipulated with tweezers on a model of natural teeth. The translucent fiber reinforcement is visible between the pontic and abutment teeth. Image of everStick product packaging including Net, Ortho, Post, and C&B variants, indicating materials used for fiber-reinforced bonding. Chemical structure diagram of polyethylene (C2H4)n repeating unit with an arrow pointing to Ribbond® Leno weave structure, illustrating material composition. Diagram labeled 'Ribbond®' showing Leno weave pattern of fiber reinforcement material. Microscopic image labeled 'Woven' showing woven fiber structure with interlaced threads at magnification scale bar 1mm. Microscopic image labeled 'Braided' showing braided fiber structure with diagonal thread patterns at magnification scale bar 1mm. Microscopic image labeled 'Unidirectional' showing parallel fiber strands without weaving or braiding pattern at magnification scale bar 1mm. **Resin-bonded FPD** **Fiber-reinforced** Fiber-reinforced bonded bridge The University of Western Australia | Oral Health Centre of Western Australia     Resin-bonded FPD Fiber-reinforced bonded bridge Clinical photo showing a dental model with a fiber-reinforced bonded bridge being placed. A metal instrument is visible near the abutment teeth, and resin material is applied to the tooth surface. Close-up photo of a small amount of yellowish resin cement on a white surface, likely prepared for application during the bonding procedure. Photo showing the insertion or adjustment of a fiber-reinforced bonded bridge between two teeth using a dental instrument. The bridge spans the gap between the abutment teeth. Photo showing the curing step of the resin-bonded FPD under blue light (curing light). The bridge is seated between the teeth, and the light is directed at the interface to polymerize the adhesive resin. **Resin-bonded FPD** Fiber-reinforced Fiber-reinforced bonded bridge **THE UNIVERSITY OF WESTERN AUSTRALIA** Oral Health Centre of Western Australia    Resin-bonded FPD Fiber-reinforced bonded bridge Clinical photo of a fiber-reinforced bonded bridge (FPD) on dental models. Shows two white artificial teeth connected by a grey woven fiber strip across the interdental space. Clinical photo showing an occlusal view of a resin-bonded FPD on a dental model. The bridge connects two adjacent teeth with visible composite bonding material on the palatal surfaces and a thin connector spanning the gap. Clinical photo showing an occlusal view of a fiber-reinforced bonded bridge on a dental model. Two teeth are joined by a thin wire-like connector, demonstrating the retainer component of the fixed partial denture. Resin-bonded FPD **3 mm** Fiber-reinforced Fiber-reinforced bonded bridge    Resin-bonded FPD Fiber-reinforced bonded bridge (3 mm) Clinical procedure image showing a dental handpiece with a white fiber-reinforced bridge being prepared or bonded on a tooth. Gloved hands are visible performing the procedure. Schematic line drawing of a tooth preparation outline for a resin-bonded FPD, illustrating the shape and extent of the prep. Close-up photograph of a prepared tooth with a horizontal reduction band indicated by an arrow labeled '3 mm', demonstrating the required thickness for the fiber-reinforced bonded bridge. **Resin-bonded FPD** **Fiber-reinforced** **Fiber-reinforced bonded bridge**    Resin-bonded FPD Fiber-reinforced bonded bridge Clinical photo showing the placement of a fiber-reinforced resin-bonded FPD. A dental instrument is manipulating a white bridge structure between two prepared teeth. Clinical photo showing the insertion of a fiber-reinforced bonded bridge into place using dental instruments. Clinical photo showing the adjustment or seating of the fiber-reinforced bonded bridge on the teeth. The University of Western Australia | Oral Health Centre of Western Australia    Clinical photo showing a fiber-reinforced bonded bridge (FPD) in place. The image displays the central incisor with a restoration that appears slightly translucent compared to adjacent teeth, demonstrating the aesthetic integration of the prosthesis. Procedure image showing the preparation or placement phase of a resin-bonded FPD. A gloved hand holds a dental instrument manipulating a tooth structure, likely illustrating the bonding process or margin finishing. Procedure image demonstrating the use of a dental tool on a prepared tooth within an arch model. This visual aids in understanding the clinical technique for preparing abutment teeth for a fiber-reinforced bonded bridge. Implant Supported Bridge The University of Western Australia Oral Health Centre of Western Australia  Implant Supported Bridge Clinical radiograph (X-ray) demonstrating an implant-supported bridge. The image shows two dental implants with threaded surfaces embedded in the jawbone, supporting a fixed prosthetic bridge structure that spans between them. This visual serves to illustrate the anatomical placement and structural integrity of the implant-supported restoration. **Implant Supported Bridge**    Implant Supported Bridge Clinical photos showing the fabrication stages of an implant-supported bridge. The top-left panel shows a metal framework with abutments attached to a dental cast. The bottom-left panel shows the same framework after being covered in white acrylic and teeth. The images are accompanied by the title 'Implant Supported Bridge'. Occlusal view of a dental cast showing a metal framework for an implant-supported bridge. The metal structure is visible on the left side, with screw access holes visible on the right side where natural teeth remain. Occlusal view of a dental cast showing a white acrylic prosthesis covering the metal framework. Screw access holes are visible through the acrylic material. CLINICAL RATIONALE **The University of Western Australia** Oral Health Centre of Western Australia  The University of Western Australia Oral Health Centre of Western Australia Clinical photo showing the maxillary left posterior region. The image displays a dental implant fixture with a metallic abutment head visible in the edentulous space where a premolar or molar is missing. Adjacent teeth include a natural tooth to the mesial and what appears to be a crown or prosthesis to the distal. The gingival tissue surrounding the implant site is visible, along with the buccal and palatal aspects of the dentition. CLINICAL RATIONALE Consequences of tooth loss • Loss of masticatory efficiency – affect systemic health • Loss of quality, width and height of bone • Loss of soft tissue volume • Aesthetics is compromised • Phonetic is compromised (dental consonants) • Occlusal instability - Loss of masticatory efficiency – affect systemic health - Loss of quality, width and height of bone - Loss of soft tissue volume - Aesthetics is compromised - Phonetic is compromised (dental consonants) - Occlusal instability **CLINICAL RATIONALE** Consequences of tooth loss • Occlusal changes: Interferences, unbalanced muscle contraction, temporomandibular disorders (TMD)   - Occlusal changes: Interferences, unbalanced muscle contraction, temporomandibular disorders (TMD) Diagram illustrating occlusal changes due to tooth loss. Shows a row of teeth with a missing molar on the right side. Arrows indicate shifting or movement of adjacent teeth into the gap, demonstrating how tooth loss can lead to misalignment. Diagram showing further consequences of tooth loss. Displays multiple missing teeth and resulting gaps in the dental arch. Adjacent teeth are shown tilting or drifting into the empty spaces, visually supporting the text's mention of 'Occlusal changes' and 'Interferences'. CLINICAL RATIONALE # Consequences of tooth loss * Occlusal changes: Interferences, unbalanced muscle contraction, temporomandibular disorders (TMD) Shortened dental arch concept Witter et al. 1999  #### Occlusal Changes - Interferences, unbalanced muscle contraction, temporomandibular disorders (TMD) #### Shortened Dental Arch Concept - Witter et al. 1999 Diagram illustrating the 'Shortened dental arch concept' from Witter et al. 1999. It shows six schematic representations of dental arches (three upper, three lower) with varying numbers of posterior teeth removed: 3 out (3 ou), 4 out (4 ou), and 5 out (5 ou). Each diagram uses white shapes for anterior teeth and black circles for remaining posterior teeth to visually demonstrate progressive tooth loss. CLINICAL RATIONALE **Rationale for Intervention:** • Is there a need for improved aesthetics? • Does the patient need to improve masticatory function? • Is there a need for improved occlusal stability? Need vs Demand #### Assessment of Need - Is there a need for improved aesthetics? - Does the patient need to improve masticatory function? - Is there a need for improved occlusal stability? #### Patient Considerations - Need vs Demand # CLINICAL RATIONALE ## Rationale for Intervention: ### Aesthetics: - What the patient wants - What the patient needs - What the patient can get What is the patient’s expectation? Can it be achieved? What is technically possible? <img>Intraoral photo showing missing tooth and dental implant.<img> <img>Photo of a person smiling with dental implants.<img>   #### Patient Expectations - What the patient wants - What the patient needs - What the patient can get #### Feasibility - What is the patient’s expectation? - Can it be achieved? - What is technically possible? Clinical intraoral photo showing a close-up of the upper dental arch with several natural teeth and one visible silver-colored dental implant fixture in the edentulous space, demonstrating the pre-prosthetic condition. Clinical photo of a person smiling, displaying a full set of aligned white teeth and lips, illustrating the aesthetic outcome or patient expectation following dental intervention. CLINICAL RATIONALE The University of Western Australia | Oral Health Centre of Western Australia - Aesthetics Lip support, high smile line   The University of Western Australia | Oral Health Centre of Western Australia - Lip support - High smile line Clinical intraoral photograph demonstrating the anterior dentition and gingival tissue. The image shows a high smile line with visible lip support, exposing the maxillary central incisors and adjacent teeth. Several metallic dental restorations are visible on the left side of the arch. Lateral profile view of a patient's face against a red background. This image illustrates the facial aesthetic regarding lip support and the vertical dimension of the lower third of the face, corresponding to the text 'Lip support, high smile line'. CLINICAL RATIONALE   Clinical photo showing the anterior view of a patient's mouth with significant dental issues. The image displays missing teeth (edentulous spaces) in both the upper and lower arches, particularly noticeable on the left side of the upper jaw. There is visible gum recession, dark staining or discoloration around some remaining teeth, and an irregular bite alignment. Clinical photo showing the anterior view of a patient's mouth after treatment. All teeth are present and restored with full-coverage crowns that appear uniform in color and shape. The gums look healthy, and the occlusion (bite) appears corrected compared to the 'before' image. Clinical Rationale of Tooth Supported Bridgework **NEVER OVERLOAD ABUTMENT TEETH!** * **Direction of Occlusal forces:** 1) Mandibular stability 2) Axial occlusal load 3) During lateral excursions: no interference in the working side 4) During lateral excursions: disocclusion in the non-working side 5) During protrusion: disocclusion of posterior teeth * **Intensity of Occlusal Forces:** - Parafuntional habits - Age, Gender **NEVER OVERLOAD ABUTMENT TEETH!** #### Direction of Occlusal Forces 1. Mandibular stability 2. Axial occlusal load 3. During lateral excursions: no interference in the working side 4. During lateral excursions: disocclusion in the non-working side 5. During protrusion: disocclusion of posterior teeth #### Intensity of Occlusal Forces - Parafunctional habits - Age, Gender **aClinical Rationale of Tooth Supported Bridgework The University of Western Australia Oral Health Centre of Western Australia Assessing potential abutment teeth: Crown/Root Ratio Root configuration Periodontal Ligament Area Ante’s Law: “Root surface area of the abutment teeth has to equal or surpass that of the teeth being replaced with pontics” ** **Fig 7-9- The combined root surface area of the canine and second molar (Ac + A2m) is exceeded by that of the teeth being replaced (A1p + A2p + A1m). A fixed partial denture would be a poor choice in this situation.** **Fig 7-10 The combined root surface area of the second premolar and the second molar (A2p + A2m) is greater than that of the first molar being replaced (A1m).**  The University of Western Australia | Oral Health Centre of Western Australia #### Criteria for Assessment - Crown/Root Ratio - Root configuration - Periodontal Ligament Area - Ante’s Law: “Root surface area of the abutment teeth has to equal or surpass that of the teeth being replaced with pontics” #### Clinical Examples - The combined root surface area of the canine and second molar (Ac + A2m) is exceeded by that of the teeth being replaced (A1p + A2p + A1m). A fixed partial denture would be a poor choice in this situation. - The combined root surface area of the second premolar and the second molar (A2p + A2m) is greater than that of the first molar being replaced (A1m). Clinical diagram illustrating Ante's Law for assessing potential abutment teeth. The image is divided into three sections: a) and b) show schematic cross-sections of a tooth with the crown/root ratio indicated by numbers (a shows ratio 2/3, b shows ratio 1/1). c) depicts a scenario marked with a red 'X' where the combined root surface area of the abutment teeth (Ac + A2m) is insufficient compared to the replaced teeth (A1p + A2p + A1m), indicating a poor choice for a fixed partial denture. d) shows a successful case with a green checkmark where the combined root surface area of the second premolar and second molar (A2p + A2m) exceeds that of the single first molar being replaced (A1m). **Clinical Rationale of Tooth** **Supported Bridgework** • **Crown-to-root ratio** Minimum **1:1** Shillingburg 1997  - Minimum ratio: **1:1** (Shillingburg 1997) Labeled diagram illustrating crown-to-root ratio for tooth-supported bridgework. Left panel shows a tooth with dimensions labeled: H (crown height), R (root length), L (total root length including apex). Right panel shows a compromised tooth with reduced root dimensions: 2/3H (reduced crown height) and 1/2A (reduced root area), indicating insufficient support. The diagram visually supports the minimum 1:1 crown-to-root ratio requirement mentioned in the text. ## Clinical Rationale of Tooth Supported Bridgework * Root shape and angulation   - Root shape and angulation Labeled diagram showing three posterior teeth (A, B, C) illustrating variations in root shape and angulation. A shows two divergent roots; B shows converging or parallel roots; C shows a single fused root structure. Clinical radiograph labeled 'The Tooth Dance!' showing dental anatomy with restorations and an endodontic instrument visible in the right panel. **Clinical Rationale of Tooth Supported Bridgework** <span style="color:blue;">Clinical Rationale of Tooth Supported Bridgework</span> **JEPSEN A. Root surface measurement and a method for x-ray determination of root surface area. Acta Odontol Scand.** **Image extracts:** - **1963.** - **mm²** - **mm²** - **ROOT SURFACE AREAS OF MANDIBULAR TEETH** - **ROOT SURFACE AREAS OF MAXILLARY TEETH** - **154 (1.0)** - **168 (1.1)** - **180 (1.2)** - **179 (1.0)** - **268 (1.7)** - **273 (1.5)** - **234 (1.3)** - **220 (1.2)** - **207 (1.3)** - **431 (2.8)** - **433 (2.4)** - **426 (2.8)** - **431 (2.4)** JEPSEN A. Root surface measurement and a method for x-ray determination of root surface area. Acta Odontol Scand. 1963. • Root surface area    #### Root Surface Area Research JEPSEN A. Root surface measurement and a method for x-ray determination of root surface area. Acta Odontol Scand. 1963. #### Root Surface Areas (mm²) - Maxillary Teeth: 154 (1.0), 168 (1.1), 180 (1.2), 179 (1.0), 268 (1.7), 273 (1.5) - Mandibular Teeth: 234 (1.3), 220 (1.2), 207 (1.3), 431 (2.8), 433 (2.4), 426 (2.8), 431 (2.4) Bar chart titled 'ROOT SURFACE AREAS OF MANDIBULAR TEETH'. Y-axis labeled in mm² ranging from 0 to 450. X-axis displays tooth outlines. Bars show values: 154 (1.0), 168 (1.1), 268 (1.7), 180 (1.2), 207 (1.3), 431 (2.8), and 426 (2.8). Bar chart titled 'ROOT SURFACE AREAS OF MAXILLARY TEETH'. Y-axis labeled in mm² ranging from 0 to 450. X-axis displays tooth outlines. Bars show values: 204 (1.1), 179 (1.0), 273 (1.5), 234 (1.3), 220 (1.2), 433 (2.4), and 431 (2.4). Clinical radiograph showing mandibular posterior teeth with a fixed dental bridge. The image demonstrates the clinical application of tooth-supported bridgework on multiple roots. **Clinical Rationale of Tooth Supported Bridgework** <!-- Image (121, 586, 914, 850) --> * Length of edentulous area **Ante’s Law** The total root surface area (periodontal membrane) of the abutment teeth for a FPD must be equal to or greater than the root surface area of the teeth being replaces (Irvin Ante, 1926) 1 2 3  #### Length of Edentulous Area - The total root surface area (periodontal membrane) of the abutment teeth for a FPD must be equal to or greater than the root surface area of the teeth being replaced (Irvin Ante, 1926). A composite figure containing three labeled panels (numbered 1, 2, and 3) illustrating Ante's Law for Fixed Partial Dentures (FPD). The figure demonstrates the clinical rationale that the total root surface area of abutment teeth must equal or exceed that of replaced teeth. Panel 1 shows two abutments with sufficient root surface area compared to the edentulous span; Panel 2 depicts a scenario where the abutments' root surface area is insufficient relative to the span; Panel 3 illustrates an extreme deficiency in root surface area. Labels beneath each panel (e.g., A2p, A1m, A2m) denote specific tooth positions. **Clinical Rationale of Tooth Supported Bridgework** Length of edentulous area - Fracture of a porcelain veneer - Breakage of a connector - Loosening of a retainer - Unfavorable soft tissue response - Fracture of abutment THE UNIVERSITY OF WESTERN AUSTRALIA | Oral Health Centre of Western Australia   #### Risks Associated with Length of Edentulous Area - Fracture of a porcelain veneer - Breakage of a connector - Loosening of a retainer - Unfavorable soft tissue response - Fracture of abutment THE UNIVERSITY OF WESTERN AUSTRALIA | Oral Health Centre of Western Australia Clinical diagram illustrating the 'Length of edentulous area' in a short span. It shows two adjacent abutment teeth with a single pontic (false tooth) between them. A downward pink arrow labeled 'F' indicates occlusal force on the pontic. Vertical lines and letters indicate dimensions: 'H' for height of the pontic crown, 'D' for the depth of the subgingival margin or periodontal space below the pontic. Clinical diagram illustrating the 'Length of edentulous area' in a long span. It shows multiple missing teeth replaced by several pontics supported by abutments at either end. Similar to the left diagram, a downward pink arrow labeled 'F' indicates occlusal force. The vertical dimension is labeled 'H', and the depth below the pontic is labeled '27D', indicating a deeper subgingival extension relative to the longer span. **Clinical Rationale of Tooth Supported Bridgework** • Dental arch shape • Opposing arch   - Dental arch shape - Opposing arch Labelled diagram of the maxillary dental arch showing tooth positions and occlusal relationships. The image includes a top-down view of the upper jaw with teeth arranged in an arch shape, highlighting the central incisors, lateral incisors, canines, premolars, and molars. Dashed lines indicate alignment or reference points for tooth-supported bridgework. Schematic representation of opposing dental arches (maxillary and mandibular) with labeled vertical measurements (c1 to c5). The diagram illustrates how teeth in both arches align vertically, emphasizing the importance of proper occlusion and spatial relationship between opposing teeth for effective tooth-supported bridgework. - **Dental arch shape** **Fig 7-20** Secondary retention (R) must extend a distance from the primary interabutment axis equal to the distance that the pontic lever arm (P) extends in the opposite direction. **Fundamentals of Fixed Prosthodontics** **Fig 7-19** The retainers on secondary abutments will be placed in tension when the pontics flex, with the primary abutments acting as fulcrums.   #### Biomechanical Principles - **Secondary Retention:** Secondary retention (R) must extend a distance from the primary interabutment axis equal to the distance that the pontic lever arm (P) extends in the opposite direction. - **Leverage and Tension:** The retainers on secondary abutments will be placed in tension when the pontics flex, with the primary abutments acting as fulcrums. (Fundamentals of Fixed Prosthodontics) Labelled diagram of dental arch shape showing tooth arrangement. The diagram includes horizontal lines indicating a primary interabutment axis and labels for 'P' (pontic lever arm) and 'R' (secondary retention). Caption: Fig 7-20 Secondary retention (R) must extend a distance from the primary interabutment axis equal to the distance that the pontic lever arm (P) extends in the opposite direction. Diagram illustrating fixed prosthodontics mechanics on a dental arch with multiple teeth. Arrows indicate forces applied to retainers on secondary abutments, showing them being placed in tension when pontics flex. Primary abutments are shown acting as fulcrums. Caption: Fig 7-19 The retainers on secondary abutments will be placed in tension when the pontics flex, with the primary abutments acting as fulcrums. **Direction of Occlusal forces** **Intensity of Occlusal Forces** Assess root surface area Length of edentulous area Root shape and angulation Crown-to-root ratio Dental arch shape Opposing arch **Clinical Rationale of Tooth Supported Bridgework** #### Summary of Clinical Rationale - Direction of Occlusal forces - Intensity of Occlusal Forces - Assess root surface area - Length of edentulous area - Root shape and angulation - Crown-to-root ratio - Dental arch shape - Opposing arch **Thanks for listening!** Thanks for listening! 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