1 FIXED PARTIAL DENTURES

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Implant-supported Cantilever FPD #5-#6-#7 SPECIAL PROBLEMS: Tilted Molar Abutment • Discrepancy between long axis of molar and premolar abutments •25 o -30 o - maximum angle of tilting Stress Distribution in Fixed Partial Dentures SPECIAL PROBLEMS: Tilted Molar Abutment • An FPD distributes forces favorably by directing forces in the long axis of the abutment teeth. • Well-aligned abutment teeth provide better support than tipped abutment teeth. • Non-axial loading → proximal crestal bone loss • Generally poor abutments Rosenstiel • Mesial wall must be over-reduced (↓ resistance) • Distal adjacent tooth may intrude on the path of insertion – Mesial surface may need re-contouring or restoration SPECIAL PROBLEMS: Tilted Molar Abutment SPECIAL PROBLEMS: Tilted Molar Abutment Rudd & Morrow Rosenstiel • Plan path of insertion / preparation design on diagnostic cast. • Surveyor may help in determination of preparation design for common path of insertion. Shillingburg • Occlusal reduction is not always the same as clearance needed. – Remove only enough tooth structure to provide necessary space for the restoration. • Allows for longer axial wall length. 12
SPECIAL PROBLEMS: Tilted Molar Abutment Tilted Molar Abutments: Proximal Half Crown Rosenstiel • Molar uprighting – optimum – Places abutment in better position for preparation – Distributes forces under loading through long axis of tooth (helps eliminate mesial bony defects) – Enables replacement of optimum occlusion Shillingburg Rosenstiel • Proximal Half Crown – does not involve distal wall • 3/4 crown rotated 90 o • Requirements: Caries-free distal surface Low incidence of caries Even marginal ridge height Short span length Tilted Molar Abutments: Telescopic Coping and Crown Tilted Molar Abutments: Non-Rigid Connector • Full crown preparation and coping with path of insertion in long axis of tooth • Full coverage crown compensates for discrepancy in paths of insertion • Must over-reduce molar to accommodate the thickness of coping and crown Shillingburg Shillingburg Too much inclination • Allows slight movement - short span •Keyway indistal of premolar to avoid intrusion of molar (mesial seating action) • Must prepare box in distal of premolar preparation – (To accommodate the female / keyway) Canine Replacement FPD (Complex) Canine Replacement FPD Shillingburg • Pontic lies outside the inter-abutment axis • Stress is greater / less favorable on maxillary arch – Forces → inside arch (weak - tension) • Stress more favorable in mandibular arch – Forces → outside arch (strong – compression) • Pontic lies outside the inter-abutment axis Shillingburg • Adjacent teeth are weakest possible abutments • Should not replace more than one additional tooth • Canine plus 2 contiguous teeth – poor prognosis – restore with implants if possible – (Splint central incisors and premolar / molar) 13
Page 1 and 2: FIXED PARTIAL DENTURES Treatment Pl
Page 3 and 4: Disadvantages of Removable Prosthes
Page 5 and 6: Abutment Evaluation: Remove all car
Page 7 and 8: Abutment Evaluation: Crown-Root Rat
Page 9 and 10: Biomechanical Problems: Bending or
Page 11: SPECIAL PROBLEMS: Pier Abutments
Page 15: Cantilever FPD: Replacement of Firs

1 FIXED PARTIAL DENTURES

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