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<p class="font_7"><strong>Note: </strong>This video follows the 2022 ADEX guidelines for the gold (#3), metal ceramic (#5) fixed partial denture (FPD) preparation for the typodont exam</p> <ul class="font_8"> <li><p class="font_8">Refer to your exam manual</p></li> </ul>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>#3 occlusal reduction</strong></p> <p class="font_8"><br></p> <ul class="font_8"> <li><p class="font_8"><strong>Tip: </strong>Half of the occlusal reduction is performed at a time; the other half is maintained for reference purposes</p></li> </ul> <p class="font_8">Orient the bur parallel to the slopes of the buccal cusps on the occlusal surface</p> <p class="font_8"><br></p> <p class="font_8">Create depth grooves on the buccal cusps at 1.0-1.2mm depth</p> <ul class="font_8"> <li><p class="font_8"><strong>Note:</strong> Allows for additional loss of tooth structure during reduction and finishing as the final occlusal reduction is 1.5mm (≥0.5mm, ≤2mm)</p></li> </ul> <p class="font_8">Join the depth grooves together</p> <ul class="font_8"> <li><p class="font_8">Remove any roughness left by the grooves</p></li> </ul> <p class="font_8">Orient the bur parallel to the slopes of the lingual cusps on the occlusal surface&nbsp;</p> <p class="font_8"><br></p> <p class="font_8">Create depth grooves on the lingual cusps at 1.0-1.2mm depth</p> <p class="font_8"><br></p> <p class="font_8">Join the depth grooves together</p> <ul class="font_8"> <li><p class="font_8">The final occlusal reduction is 1.5mm (≥2mm, ≤2mm)</p></li> </ul> <p class="font_8">Compare the occlusal reduction against the reduction guides; use the probe to measure</p> <ul class="font_8"> <li><p class="font_8"><strong>Tip: </strong>Ensure that the central groove is appropriately reduced, as this area is frequently under-reduced</p></li> </ul> <p class="font_9"><br></p> <p class="font_9"><strong>Bur options: </strong>coarse to medium grit chamfer end tapered diamond</p>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>#3 buccal reduction</strong></p> <p class="font_8"><br></p> <p class="font_8">Create 0.8mm depth grooves</p> <ul class="font_8"> <li><p class="font_8">Three parallel to the long axis of the tooth. One DG at the center of the wall, and one in each mesial and distal transitional line angle</p></li> <li><p class="font_8">The tip of the diamond rotary instrument should be positioned 0.5mm supragingival</p></li> </ul> <p class="font_8">Join the depth grooves together</p> <ul class="font_8"> <li><p class="font_8">The final buccal reduction is 1mm (&gt;0.5mm, ≤2mm) with dual planes, corresponding to the occlusal ⅓ of the tooth and the long axis of the tooth (⅔)</p></li> <li><p class="font_8">The buccal reduction tapers to 0.5-1mm along the gingival margin</p></li> </ul> <p class="font_8">Create a chamfer margin</p> <ul class="font_8"> <li><p class="font_8">0.5-1mm (visually / explorer detectable, ≤1mm) wide margin circumferentially</p></li> <li><p class="font_8">0.5mm supragingival (equagingival, ≤1.5mm supragingival) margin height</p></li> </ul> <p class="font_8">Compare the reduction against the BL reduction guide, use the probe to measure</p> <p class="font_9"><br></p> <p class="font_9"><br></p> <p class="font_9"><strong>Bur options: </strong>coarse to medium grit chamfer end tapered diamond</p>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>#3 lingual reduction</strong></p> <p class="font_8"><br></p> <p class="font_8">Create 0.8mm depth grooves</p> <ul class="font_8"> <li><p class="font_8">Three parallel to the long axis of the tooth</p></li> </ul> <p class="font_8">Join the depth grooves together</p> <ul class="font_8"> <li><p class="font_8">The final lingual reduction is 1mm (&gt;0.5mm, ≤2mm) lingual reduction</p></li> <li><p class="font_8">The lingual reduction tapers to 0.5-1mm along the gingival margin</p></li> </ul> <p class="font_8">Create a chamfer margin</p> <ul class="font_8"> <li><p class="font_8">0.5-1mm (visually / explorer detectable, ≤1mm) wide margin circumferentially</p></li> <li><p class="font_8">0.5mm supragingival (equagingival, ≤1.5mm supragingival) margin height</p></li> </ul> <p class="font_8">Compare your reduction against the BL reduction guide, use the probe to measure</p> <p class="font_9"><br></p> <p class="font_9"><br></p> <p class="font_9"><strong>Bur options: </strong>coarse to medium grit chamfer end tapered diamond</p>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>#3 proximal reduction</strong></p> <p class="font_8"><br></p> <p class="font_8">Orient the bur parallel to the long axis of the tooth on the buccal surface</p> <p class="font_8"><br></p> <p class="font_8">Penetrate the tooth from the buccal and move the bur lingually in a sawing motion, carefully avoiding the adjacent teeth</p> <p class="font_8"><br></p> <p class="font_8">Retain an enamel “shell” of the proximal tooth structure to protect the adjacent teeth during tooth preparation</p> <ul class="font_8"> <li><p class="font_8"><em>Optional: Break the shell using a hand instrument</em></p></li> </ul> <p class="font_8">Ensure that the proximal wall tapers are approximately parallel to ≤12º per wall</p> <p class="font_8"><br></p> <p class="font_8">Compare your reduction against the OC reduction guide, use the probe to measure</p> <p class="font_9"><br></p> <p class="font_9"><br></p> <p class="font_9"><strong>Bur options: </strong>long needle diamond</p> <p class="font_9"><strong>Hand instrument options: </strong>enamel hoe, hatchet</p>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>Refine the preparation of #3</strong></p> <p class="font_8"><br></p> <p class="font_8">Refine the chamfer margin so that it is:</p> <ul class="font_8"> <li><p class="font_8">0.5-1mm (visually / explorer detectable, ≤1mm) wide margin circumferentially</p></li> <li><p class="font_8">0.5mm supragingival (equagingival, ≤1.5mm supragingival) margin height</p></li> <li><p class="font_8"><em>Optional: Use air cooling alone to increase visibility with intermittent water coolant</em></p></li> </ul> <p class="font_8">Ensure that all cusps are rounded</p> <ul class="font_8"> <li><p class="font_8">Preserve the overall geometric contour of the occlusal slopes and primary anatomy</p></li> </ul> <p class="font_8">Remove J-margins using rotary instrumentation or hand instruments</p> <p class="font_8"><br></p> <p class="font_8">Round all line angles</p> <p class="font_9"><br></p> <p class="font_9"><br></p> <p class="font_9"><strong>Bur options: </strong>medium to fine grit finishing diamond</p> <p class="font_9"><strong>Hand instrument options: </strong>enamel hoe, hatchet</p>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>Refine the preparation of #5</strong></p> <p class="font_8"><br></p> <p class="font_8">Refine the chamfer / shoulder margin on the buccal so that it is:</p> <ul class="font_8"> <li><p class="font_8">1-1.5mm (&gt;0.5mm, ≤2mm) wide chamfer or beveled shoulder margin on the buccal</p></li> <li><p class="font_8">Bevel ≤1.5mm if utilized</p></li> <li><p class="font_8">0.5mm supragingival (≤0.5mm subgingival, ≤1.5mm supragingival) margin height</p></li> </ul> <p class="font_8">Refine the chamfer margin on the proximal and lingual so that it is:</p> <ul class="font_8"> <li><p class="font_8">0.5-1mm (visually / explorer detectable, ≤1mm) wide chamfer margin</p></li> <li><p class="font_8">0.5mm supragingival (≤0.5mm subgingival, ≤1.5mm supragingival) margin height</p></li> </ul> <p class="font_8">Remove J-margins using rotary instrumentation or hand instruments</p> <p class="font_8"><br></p> <p class="font_8">Round all line angles</p> <p class="font_9"><br></p> <p class="font_9"><br></p> <p class="font_9"><strong>Bur options: </strong>medium to fine grit finishing diamond</p> <p class="font_9"><strong>Hand instrument options: </strong>enamel hoel, hatchet</p>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>Path of draw</strong></p> <p class="font_8"><br></p> <p class="font_8">Ensure that the path of draw of #5 is coincident with that of #3, and correct the angulation of the walls / taper, as needed</p> <ul class="font_8"> <li><p class="font_8"><strong>Tip: </strong>Use a large intraoral mirror to inspect the path of draw for #5 and #3 at the same time. No undercuts should be apparent on either tooth when the path of draw is coincident</p></li> </ul> <p class="font_8"><strong>Note:</strong> If it is necessary to over-taper a tooth to create a coincident path of draw, favor over-tapering the larger tooth (#3)</p>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>Ensure proper reduction</strong></p> <ul class="font_8"> <li><p class="font_8">Compare both preparations against the reduction guides, using the probe to measure</p></li> </ul>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>Tip: </strong>Measure the diameter of your burs, in order to use the burs for the depth grooves in subsequent steps</p> <ul class="font_8"> <li><p class="font_8">Practice with the same burs you plan to use during the day of the exam</p></li> </ul>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>Fabricate reduction guides</strong></p> <p class="font_8"><br></p> <p class="font_8">Fabricate two putty indices</p> <ul class="font_8"> <li><p class="font_8">Mix half a scoop of base with half a scoop of accelerator</p></li> <li><p class="font_8">Knead until the color is uniform and all streaks have disappeared</p></li> <li><p class="font_8">Adapt the putty to cover the labial and lingual surfaces of the tooth as well as the corresponding surfaces of at least one adjacent tooth</p></li> <li><p class="font_8">Allow the putty to polymerize for approximately 2 minutes (or according to the manufacturer’s instructions)</p></li> </ul> <p class="font_8">Remove the putty and section the indices</p> <ul class="font_8"> <li><p class="font_8">Bucco-lingual index: Cut the index in half bucco-lingually (sagittally) across #5 and #3</p></li> <li><p class="font_8">Occlusal-cervical index: Cut along the occlusal surface to separate the index into a labial and lingual half</p></li> </ul> <p class="font_8">Place the indices on the teeth to check fit</p> <ul class="font_8"> <li><p class="font_8"><strong>Tip:</strong><em><strong> </strong></em>Make matrices specific to the exact teeth you are using as typodont teeth may vary</p></li> </ul>

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3-x-5 FPD Preparation

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<p class="font_7"><strong>Perform the gross reduction of both #3 and #5 prior to refining either preparation</strong></p> <ul class="font_8"> <li><p class="font_8"><strong>Tip: </strong>Use water coolant with your high speed to prevent burning the typodont teeth</p></li> </ul>

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3-x-5 FPD Preparation

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