Design Planing

8/3/2019 Design Planing

1/17

Design Planning


2/17

Selection of the type of

prosthesis 3 types

Removable Partial Denture (RPD)

Tooth-Supported Fixed Partial Denture (FDP)

Implant-Supported Fixed Partial Denture

May be combined in the same arch

Treatment Simplification

As simple as possible


3/17

Wrong occlusal

Plane

Proper occlusal

Plane

Normal state Edentulous

State


4/17

Removable Partial Denture

Edentulous spaces Greater than 2 posterior teeth

Anterior spaces greater than 2 incisors

Spaces that include a canine and two other contiguous teeth

i.e. Central incisor, lateral incisor and canine or lateral incisor, canine

and first molar

Abutment Configuration

No distal abutment

Multiple or bilateral edentulous spaces

Abutment conditions Short clinical crowns

Insufficient abutment


5/17

Abutment Alignment

Tipped abutments can be tolerated

Widely divergent abutment alignment

Occlusion More adaptable to irregularities in a healthy opposing natural

dentition

Ridge form

Gross tissue loss in residual ridge

General Features Dry mouth is a contra indicator

Cheap

Acceptable oral hygiene

Treatment simplification

Advanced age

Systemic health problems

More acceptable to dentition in transition to edentulous state


6/17

Conventional tooth-supported

fixed partial denture Span Length

Posterior Span 2 or fewer

Incisors 4 or fewer

Span Configuration

Usually has distal abutment but can be used with short cantilever

pontic

Abutment alignment

Less than 25 inclination can be accommodated by preparation

modification Abutment condition

Needs to be good

Nonvital teeth can be used if there is sufficient coronal tooth

structure


7/17

Occlusion

Favorable loading (magnitude, direction, frequency, duration]

Periodontal Condition

Good alveolar bone support

Crown-root ratio 1:1 or better

No mobility

Favorable root morphology

Provides rigid stabilization

Ridge Form

Moderate resorption

No gross soft tissue defects

General features

Dry mouth High risk of caries

Good for Mandibular tori (bony growth in the mandible near tongue)

Palatal soft tissue lesion

Large tongue

Exaggerated gag reflex

Must be within dentist's skills


8/17

Resin-bonded tooth supported

fixed partial denture Span Length

Single tooth (anterior)

Possible for 2 incisors

Span configuration

Abutments mesial & distal to pontic

Abutment alignment

Less than 15 inclination mesiodistally

Should be in same buccolingual plane

Preparations are not easily modified because of minimal

reduction Abutment conditions

Defect-free abutments

Incisor, premolar replacements


9/17

Occlusion

Cannot be used for incisor replacement in presence of deep

vertical overlap

Periodontal Condition No mobility

Ridge Form

Moderate resorption

No gross soft tissue defects General Features

Well suited for young patients

Can be used for replacing molars if masticatory muscles are not

too well developed


10/17

Implant-supported fixed

partial denture Span Length

Single Tooth

2 to 6 unit span

Span configuration

No distal abutment

Occlusion

Occlusal forces must be as nearly vertical as possible to prevent

unfavorable lateral loading of implants

Periodontal condition Dense bone


11/17

Ridge form

Broad, flat ridge

General features

Able to survive in dry mouth

May be better choice if teeth will require extensive treatment

and will still be weak, questionable abutments

Unfavorable attitude toward RPD

Must be within dentist's skills


12/17

Crown Ratio

The optimum crown-root ratio

for a fixed partial denture

abutment is 2:3 (A).

A ratio of 1:1 is the minimum

that is accepted (B).


13/17

Root Configuration

Roots that are broader labio-lingually than they are

mesiodistally are preferable to roots that round in cross

section

Multirooted posterior teeth with widely separated roots will

offer better periodontal support than roots that converge,fuse, or generally present a conical configuration

The molar with divergentroots (A) will be better

abutment tooth than the one

whose roots are fused (B).


14/17


15/17

Biomechanical Considerations


16/17

Special Problems

Tilted Molar Abutments

Will not seat

due to the

distal tooth

Proximal half

crown as a

retainer

Non rigid

connector on

the premolar

Orthodontic approach also possible


17/17

Cantilever Fixed Partial Dentures

A pontic premolar

has been used

instead of molar to

minimize stress on it

Documents

Design Planing