A simplified take on the steps to designing a Fixed partial denture. This presentation also includes an overview of abutment preparation, associated finishes and methods of impression taking prior to the designing of the prosthesis itself

1. Design of a Fixed Partial Denture
with Abutment Tooth Preparation
Dr. Taseef Hasan Farook (BDS)(DU)
Bangladesh Dental College

2. Crown- Extracoronal restoration that covers the
outer surface of the remaining clinical crown
and restore structure and function
Bridge/ Fixed Partial Denture- A restoration or
replacement which is attached by a cementing
medium to natural teeth, roots or implants-
GPT

3. Indications of Fixed partial Denture:
1. Short span edentulous arch
2. Periodontally strong supporting teeth (abutment)
3. Inadequate tissue support ex. Excessive ridge resorption
4. Aesthetic Consideration
Contraindications of fixed partial denture
1. Young patients with large pulp chamber
2. Patient attitude (uncooperative patients)
3. Recurrent/ grossly carious dentition
4. Athletes participating in contact sports
5. Congenitally malformed teeth
6. Bilaterally missing teeth which require cross arch stabilization
7. Weak periodontal condition of abutment teeth

4. Congenital malformation of tooth Poor periodontal condition
Pulp chamber thickness change with age (young to old)

5. Step 1a: Diagnosis
• History of physical and medical conditions
• Patient attitude According to House’s
Classification
• Extraoral examination of TMJ and muscles of
mastication
• Intraoral examination of oral hygiene,
periodontium and any intraoral pathologies
• Radiograph to determine caries, alveolar bone
support, morphology of abutment and presence
of any underlying pathologies along with
examination of any existing prostheses.

6. Radiograph of missing space
Radiograph of 3 unit FPD with rigid
connectors
Radiograph of a 3 unit FPD with non rigid
connector
Radiograph of an implant abutment

7. Step 1b: Treatment planning
• Construction of diagnostic casts of both arches
• Occlusal rehabilitation- Intentional alteration of
the occlusal surfaces of teeth to change their
form- GPT
• Mount the cast on the articulator and assess the
height, rotation and inclination of abutment
teeth along with a general idea about the present
occlusion.
• Determine the need for preprosthetic mouth
preparation ex. For unfavorable residual ridge

8. Treatment Planning
• Selection of type of material according to the
condition of abutment teeth and surrounding
periodontium (ex. Conventional FPD for sound
abutment teeth and implant supported FPD
for inadequate abutment support)
• Provide the patient with a few treatment
options according to your diagnosis and let
the patient choose according to their needs
and ability.

9. Preparation of a diagnostic cast.
Mounting a cast and surveying to
check for tooth borne undercuts,
path of insertion of retainer,
occlusal contact etc.

10. Step 2: Abutment Selection
Abutment
A tooth, a portion of tooth or that portion of an
implant used for the support of a fixed or
removable prosthesis- GPT

11. Selection Criteria of Abutment
1. Location and condition of abutment: grossly
decayed or pulp capped tooth avoided
2. Root configuration: Irregularly curved long
roots preferred with greater labiolingual
width
3. Crown:root ratio should be <1 (ideally 2:3)
4. Must Satisfy Ante’s Law
5. Vital Tooth preferred

12. Ante’s Law
The Combined pericemental area of all
abutment teeth supporting a fixed dental
prosthesis should be equal to or greater in
pericemental area than the tooth or teeth to be
replaced- GPT
Satisfies Ante’s Law Does not Satisfy Ante’s Law

13. Types of abutment
• Ideal Abutment: matches all selection criteria
• Cantilever: abutment present on only one side
of the fixed prosthesis
• Pier abutment: a natural tooth located
between terminal abutments to support the
prosthesis
• Tilted abutment
• Others: Endodontically treated, Post core,
periodontally weakened abutment

14. Types of Abutment
Tilted abutment Cantilever abutment
Pier abutment Post core abutment

15. Special Considerations for Abutment
• Single missing Canine: Since the canine lies
outside the inter-abutment axis, support should
be taken from either both central and lateral
incisors or the premolars & molar
• Tilted posterior teeth: fabricate a partial veneer
crown or a telescopic crown if pre-prosthetic
management is not carried out
• Pier abutment: the central abutment is subjected
to torsion and leverage, hence non rigid stress
breakers should be used at pier connector

16. Canine lies outside the inter-abutment line
Stress breaker for pier abutment

17. Special Considerations for Abutment
• For extensively damaged/Decayed tooth:
Carry out endodontic obturation, then remove
2/3rd of the Gutta percha to create a vacuum.
• The vacuum is then filled by preformed or
custom made posts. The posts should have an
apical lock to maintain appropriate canal
length. The core is then built on the post. This
procedure is known as Dowel Core Crown/
Post Core Crown

18. Procedure for Dowel Core Crown (Textbook of Endodontology, Preben Horsted-Bindslev)

19. Special Considerations for Abutment
• Implant Abutment: used for long span edentulous arches with
minimal abutment support.
Implant: a substance placed into the jaw to support a crown or a
fixed/removable appliance.
Factors affecting implant success:
• osseo/fibrointegration,
• bone turnover,
• healing rates,
• appropriate occlusal stress,
• infection free surrounding soft tissue.

20. Step 3: Preparation of abutment
tooth aka Tooth preparation
Tooth Preparation:
The mechanical alteration of a defective,
diseased or injured tooth to receive a restorative
material that reestablishes a healthy state for
the tooth, including aesthetic corrections where
indicated and normal form and function

21. Principles of Tooth Preparation

22. Principles of tooth preparation
Biological consideration Mechanical Consideration Aesthetic Consideration
Condition of adjacent teeth Retention form Color selection
Soft tissue condition Resistance form Material selection
Status of the pulp Conservative margin Type of design
Biological width integrity Miniature form
Occlusal harmony Path of insertion and tilt
Conservative tooth structure Appropriate finish lines

23. Tooth Preparation: Importance of
Biological Width
(a) Histological sulcus (0.69 mm), (b) Junctional Epithelial attachment (0.97
mm), (c) Connective tissue attachment (1.07 mm), (d) Biologic width (b+c)
The prepared tooth finish line must not
extend or violate the junctional epithelium
as it will damage the periodontium.
According to the biological width, 3 types of
marginal finish lines can be obtained:
1. Supragingival: above the histological
sulcus
2. Equigingival: at the histological sulcus
3. Subgingival: below the histological sulcus

24. Gingival Margin Finish
• Supragingival Finish: easier to prepare with easy finish.
Restorations and impressions are made easily without soft
tissue injury
• Subgingival Finish: additional retention is needed with margin
of the crown hidden behind the labiogingival crest. Root
sensitivity can not be controlled by conservative dentin
bonding agents

25. Gingival retraction for Exposure of operating
site and construction of Finish line
For maximal exposure of operating site
• Can be done by Copper bands, retraction cords and
rubber dam.
• Retraction can be done chemically via astringents
(like Aluminium Chloride) or surgically
Gingival retraction cord

26. Gingival retraction for finish line exposure
(A commercial brand of retraction astringent)

27. The Different Finish line Designs
Feather edge/Knife Edge/Shoulderless-
Advantage:
1. conservative tooth structure
2. Margins used for full veneer crowns, small crowns and already designed
margins
Disadvantage:
1.Fail to provide adequate bulk at margins for strength
2. Over contoured restorations

28. The Different Finish line Designs
Chamfer: An obtuse angle at the axial wall of the tooth surface
and the prepared margin
Disadvantage
Tilting it away leaves an undercut, tilting it towards the tooth
leads to over reduction

29. The Different Finish line Designs
Shoulder/ butt joint (90 degree joint)
Advantage: allows substantial room for veneer and facial parts
of metal ceramic crowns
Disadvantage: Less conservative tooth structure
Modifications: 1. Shoulder with bevel 2. Sloped shoulder
Shoulder by flat end fissure bur
Chamfer by torpedo bur

30. The Different Finish line Designs
Shoulder with Bevel
Allow improved aesthetic as metal margins can be trimmed down to a knife
edge and hidden in the sulcus without moving epithelial attachment
Sloped shoulder/ angulated shoulder
A 120 degree slope on the facial aspect leaves sufficient bulk as well as
improving aesthetics

32. Preparation of Tooth Miniature
Anterior Teeth Posterior Teeth
1. Create incisal Guiding grooves
2. Incisal reduction by fissure bur
3. Create facial guiding grooves
4. Facial reduction by tapered fissure bur
5. Interproximal reduction by fine needle
fissure bur
6. Lingual reduction by teardrop/football
bur
7. Finish lines: either Shoulder or
Chamfer with appropriate functional
bevels
1. Create occlusal Guiding grooves
2. Occlusal reduction , reduce functional
cusp more than non functional cusp
by fissure bur
3. Buccal and Lingual reduction
4. Interproximal reduction
5. Bevel functional cusp and apply
appropriate finish lines: Shoulder/
Chamfer/knife edge
Different burs used in
tooth preparation

33. A) Natural tooth B) Functional groove C) Occlusal reduction D) Interproximal reduction
E) Bucco-lingual Reduction F) Finish Line - Shoulder
Fig: Tooth
preparation of
posterior teeth

34. Fig: Posterior tooth reduction

35. Fig: Anterior tooth reduction (with pin ledge)

36. • Amount of reduction depends on the material to be used for
the fabrication of the fixed prosthesis:
Example: Full Veneer crowns require greater thickness hence
more tooth structure needs to be cut as opposed to full metal
crowns which require thin sections and hence less tooth
structure needs to be sacrificed.
Anterior tooth preparation
Posterior tooth preparation

37. • Finish Line depends on aesthetics as well as the
thickness of the prosthesis.
Example: shoulder finishes provide greater surface area
and hence are preferred for Full veneer crowns
whereas Chamfers are preferred for metal crowns.

38. Step 4: Impression of prepared abutment and
operating site for fixed partial denture design
Isolation of the Impression field by:
• rubber dam
• suction devices
• Antisialogogue- (example: Proantheline
bromide, Methantheline bromide)
• Local anesthetic solution
• Gingival finish line isolation by retraction cords
and astringents

39. Impression Technique for fixed partial
denture
When using elastomer (available in various consistencies
like light, medium, heavy and putty), the impression can
be recorded as:
• Single mix technique with stock/custom tray- medium
body elastomer loaded onto tray, light body syringed
into operating site
• Double mix technique with stock/custom tray-
primary loadout with medium body followed by light
body wash on the tray along with light body syringed
into operating site.
• Others: triple mix technique, closed bite technique

40. Impression Technique for fixed partial
denture
• Single Mix putty wash impression technique

41. Impression Technique for fixed partial
denture
• Double mix putty wash technique

42. Parts of a Fixed Partial Denture
Retainer
Pontic
Connector

43. Step5a: Retainer design
Retainer
The part of a fixed partial Denture which unites
the abutments to the remainder of the
restoration- GPT

44. Selection of type of retainer
• Full Veneer- For extensively damaged teeth
• Partial Veneer- For teeth with insufficient natural tooth material
present for full veneer
• Conservative/ Acid etched retainer- For minimum tooth reduction,
ideal for anterior teeth. They have poor strength but good aesthetic
• Telescopic retainer- for abutment teeth which are not in long axis
with the path of insertion of the prosthesis. (Requires Coping)
• Pin retained crown- if two abutment teeth are not aligned parallel
to each other
• Full metal crown- when minimum tooth reduction is indicated with
strength being a necessity
• Metal Ceramic Jacket crown- Veneer over the buccal or labial
aspect for aesthetic consideration.

45. Full Veneer Crown
Metal Ceramic Jacket Crown
Telescopic Crown
Pin retained Crown

46. Step 5b: Pontic Design
Pontic
An artificial tooth on a fixed partial denture
that replaces a missing tooth, restores its
functions and usually fills the space previously
filled by a natural crown- GPT

47. Design Criteria for a Pontic
1. Edentulous space available- will determine pontic size
2. Residual Alveolar ridge contour- determines the need for coping
3. Occlusal load on the pontic- if high, the pontic should have wider
dimensions to support the stress. Reduce occlusal table to
decrease occlusal load
4. Cusps: preserve functional cusps, preserve maxillary buccal cusp
for aesthetic, preserve lingual cusp for tongue protection
5. Proximal Embrasure- sufficient space for hygiene practice
6. Anterior teeth pontic- Should have aesthetic contact with the
residual alveolar ridge
7. Posterior teeth pontic- Smooth minimal contact for hygiene
practices. Sanitary pontic often preferred

48. Selection of Pontic (according to Rosenstiel et al)
With Mucosal Contact Without Mucosal Contact
Contact with ridge Mucosa No contact with the ridge mucosa
Full facial contact Approx. 3mm above cervical contact
More Aesthetic More hygienic
Usually for anterior teeth Usually suitable for posterior teeth
Examples: Stein pontic, ridge lap pontic,
Modified ridge lap pontic, Ovate pontic
Example: Bullet Pontic, Hygienic / Sanitary
pontic

49. fixed removable partial denture: In
case of resorbed alveolar ridge
• Fabrication of
Andrew’s Bridge
System:
a removable
prosthesis is retained
by a bar and sleeve
attachment to fixed
retainers on the
either side of the
edentulous space.

50. Step 5c: Connector Design
Connector
The portion of a fixed partial denture that
unites the retainer and pontic- GPT

51. Selection of Connector
• Rigid Connectors: transfer entire load directly to
the abutment. (Can be cast or soldered)
• Non Rigid Connector: When abutments are not
parallel to each other producing multiple paths of
insertion. Usually done by Tenon Mortise
connectors
• Loop Connector: In order to maintain an existing
diastema
• Cross pin, Wings and Split connector: For tilted
abutment teeth

52. Tenon Mortise Non-Rigid Connector
Wing Connector Split Connector

53. Design for Replacement of Maxillary
Incisor
• Support obtained from a single/ group of posterior teeth
(usually molars) in the form of Spring Cantilever
Disadvantage: The bar may interfere with speech and
mastication with food entrapment and subsequent tissue
hyperplasia

54. After design of the denture
The cast with design plans are carried over to
the Laboratory for appropriate fabrication (wax
pattern with subsequent metal casting,
porcelain furnace treatment or resin processing)

55. References:
• Herbert T. Shillingburg, Fundamentals of Fixed Prosthodontics, 3rd edition, 1996
• Deepak Nallaswamy, Textbook of prosthodontics, 2003
• Nugala B, Santosh Kumar B B, Sahitya S, Krishna P M. Biologic width and its
importance in periodontal and restorative dentistry. J Conserv Dent 2012;15:12-7
• Yaqoob A, Rasheed N, Ashraf J, Yaqub G. Nonrigid semi-precision connectors for
FPD. Dent Med Res 2014;2:17-21
• Yogesh Rao, Pankaj Yadav, Mariette D’Souza, Jagjeet Singh, Anurag Jain, .BAR AND
SLEEVE ATTACHMENT: A REPORT OF TWO CASES.Journal of Clinical and Diagnostic
Research [serial online]2013 Dec[cited:2018 Jan 14] 12 3096 – 3098
• Ashu Sharma, G. R. Rahul, Soorya T. Poduval, Assessment of Various Factors for
Feasibility of Fixed Cantilever Bridge: A Review Study:ISRN Dentistry volume 2012
(2012), Article ID 259891, 7 pages
• Various slideshare online presentations by various authors
• Presentations by Indian Dental Academy
• Pictures from the internet

56. Thank You