1) Treatment planning in fixed prosthodontics involves evaluating factors like span length, abutment condition, occlusion, and patient factors to determine the best type of prosthesis for replacing missing teeth. 2) Key considerations for different prosthesis types include abutment support and alignment for tooth-supported fixed partial dentures, adequate bone for implant-supported prostheses, and span length and patient factors for removable partial dentures. 3) Biomechanical factors like span length, pontic thickness, and connector design must also be considered, as they impact the rigidity and stresses experienced by any fixed prosthesis.

1. Treatment planning in
Fixed Prosthodontics
Dr Meenu Merry C Paul
Professor-Prosthodontics
Malabar Dental College&Research Centre

2. Prosthodontics
The dental speciality pertaining to the diagnosis, treatment
planning,rehabilitation & maintenance of oral function, comfort,
appearance and health of patients with clinical conditions associated
with missing or deficient teeth and/or maxillofacial tissues using
biocompatible substitutes(GPT)

3. Teeth supporting each other...A state of dynamic equilibrium
(Tooth position&alignment are maintained by interaction b/w teeth)
Tooth loss…….
Structural integrity of dental arch is
disrupted…

4. Tooth loss…….
Structural integrity of dental arch is disrupted…
Subsequent realignment of teeth…..
Adjacent /opposing teeth migrate to the
vacant space(supraeruption,tilting…)

5. Restoring occlusion by correcting occlusal plane & placement of FPD

6. “Preservation of that which remains
is of utmost importance and
not the meticulous replacement
of that which has been lost………”
(Muller De Van…1952)

7. Selection of type of prosthesis
Abutment evaluation
Biomechanical considerations
Special problems

8. Selection of the type of prosthesis
Removable partial denture (RPD)
Tooth-supported fixed partial denture(FPD)
Resin-bonded tooth-supported FPD
Implant-supported FPD

9. In treatment planning,the principle to be kept in mind……………
TREATMENT SIMPLIFICATION

10. Fixed partial denture
Any dental prosthesis that is luted,screwed or
mechanically attached or otherwise securely
retained to natural teeth,tooth roots and/or
dental implant abutments that furnish the
primary support for the dental prosthesis

11. RPD
Immediate teeth replacement (after extraction)
Span length-Longer span…
-posterior-more than 2/3 teeth
-anterior-more than 4 incisors
Span configuration-No distal abutment
-multiple/bilateral edentulous space
Abutment alignment-tipped abutments
-widely divergent alignmnt

12. Abutment condition-Short clinical crowns
-insufficient abutment
Occlusion- adapts to irregularities in
opposing dentition
Periodontal-Poor periodontal support of
remaining teeth
Ridge form- with gross tissue loss
General - Advanced age
Low finance
Dry mouth-low caries risk with RPD
Acceptable oral hygiene

13. TOOTH-SUPPORTED FPD
Span length -Posterior span-2/fewer teeth
-Incisors- 4/fewer teeth
Span configuration - Distal abutment present
Abutment alignment- less than 25°inclination can be
accommodated by preparation modification

14. Abutment condition-non vital teeth can be used,
if it has crown height
Occlusion- Favorable occlusal loading
(magnitude,direction,frequency,duration)
Periodontal -good bone support,no mobility
-crown-root ratio 1:1 or better
Ridge form -moderate resorption
- no gross soft tissue defects

15. General
- Dry mouth-high caries risk
(minimized by flouride application)
- Large tongue
- Exaggerated gag reflex
- Mandibular tori
- palatal soft tissue lesions
- unfavorable attitude towards RPD
- muscular discoordination

16. RESIN–BONDED
TOOTH–SUPPORTED FPD
Span length-Single tooth(incisor/premolar)
Span configuration-Requires an abutment
mesial/distal to edentulous area/pontic Abutment alignment- <15°inclination
mesiodistally
-should be in same faciolingual plane

17. Abutment condition- defect free
-incisor/premolar replacements Occlusion- deep bite in incisors-
not used Periodontal-no mobility
Ridge form-moderate resorption
-no gross soft tissue defects
General –young patients

18. IMPLANT-SUPPORTED FPD
Span length-Single tooth replacement
-2 to 6 unit span(multiple/single unit/FPD)
Span configuration-No distal abutment
Abutment alignment-implant/abutmt
alignment precision

19. Abutment condition- defect free abutments Occlusion- Vertical occlusal
forces to prevent
unfavorable lateral loading of implants Periodontal-Dense
bone
Ridge form-broad,flat ridge
General –survive in dry mouth
-unfavorable attitude toward RPD

20. Abutment evaluation
Vital/nonvital abutment
Roots&supporting tissues are evaluated:
Crown-root ratio
Root configuration
Periodontal ligament area

21. Crown-root ratio
•length of tooth occlusal to crest of alveolar bone
compared with length of root embedded in bone
- optimum crown/root ratio for a tooth to
be used as abutmnt is 2:3
- minimum is 1:1

22. Root configuration
Roots that are broader labiolingually than are mesiodistally are
preferred than roots that are round in cross section

23. Multirooted posterior teeth with widely separated roots better than
converging/fused/conical roots

24. Periodontal Ligament Area
(Root surface area) (Area of attachment of periodontal ligament to root)
-Larger teeth…greater surface area

25. Ante’s law
Combined pericemental area of all abutment
teeth supporting an FPD should be equal or
greater than the pericemental area of
tooth/teeth being replaced

26. Not ideal

27. Biomechanical considerations
- Longer spans are less rigid
- Bending/ deflection varies directly with cube of length &
inversely with cube of the occlusogingival thickness of the
pontic

28. Deflection is 27 times as great(27x)…… when span length is tripled (3p)
Longer spans are less rigid

29. There will be 8 times as much deflection (8x)….. if the thickness is decreased by one-half (t/2)

30. Dislodging forces on FPD retainer tend to act in mesiodistal direction,whereas on
a single tooth restoration it is buccolingual
Preparation modification needed for greater resistance & structural
durability(multiple grooves-buccal&lingual surfaces)

31. Retainers on secondary abutments will be placed in
tension when pontics flex, with the primary
abutments acting as fulcrums

32. Pier Abutments
Tilted Molar Abutments
Canine-Replacement FPD
Cantilever FPD

33. Pier Abutment
An edentulous space on both sides of a tooth, creating a lone, freestanding pier abutment

34. Rigid connectors b/w pontics & retainers are not used in pier abutment cases.
Stress-breaking device is needed
Keyway of connector is placed within distal
contours of pier abutment
Key is placed on mesial side of distal pontic

35. If a nonrigid connector is placed on distal side of retainer
on a middle abutment, movement in a mesial direction will
seat the key into the keyway
If a nonrigid connector is placed on the mesial side of middle
abutment, mesially directed movement will unseat the key

36. Tilted Molar Abutment
When a mandibular molar tilts mesially,there is discrepancy b/w long axis of molar & premolar

37. FPD will not seat because the tooth distal to the FPD intrudes on the path of insertion

38. Orthodontic appliance for uprighting tilted molar- helical uprighting spring
Proximal half crown as a retainer on tilted molar abutment
Telescope crown & coping as retainer on tilted molar
Nonrigid connector on distal aspect of premolar retainer compensates for inclination of
molar

39. Maxillary canine is subjected to more damaging stresses because the
forces are directed outward & pontic lies farther outside the
interabutment axis
Canine-Replacement FPD
An FPD replacing a mandibular canine is more favourable because the forces
are directed inward & pontic will be closer to interabutment axis

40. Cantilever FPD
Forces on pontic of a cantilever FPD tend to tip
the FPD /abutment tooth

41. References and Pictures
Shillingburg: Fundamentals of Fixed Prosthodontics