Download Topics to be covered today - Randwick College Wiki

Topics to be covered today:

Identifying landmarks

Principles of RAPD design in relation to RAPDs

Advantages and disadvantages of a RAPD compared to a
Fixed Partial Denture

Advantages of a RPI design compared to a Lingual plate
design

Advantages of a RAPD compared to an Acrylic partial denture

Relief wax
IDENTIFYING LANDMARKS ON DENTAL MODELS RELATING
TO DESIGN OF RAPD










Remaining natural dentition
Incisive papilla
Gingiva
Frenum
Sulcus
Rugae
Saddles
Occlusal surfaces (natural teeth)
Cingulum surfaces (natural teeth)
Incisal edges (natural teeth)
These notes are now available online
http://randwick.sydneyinstitute.wikispaces.net/Dental+Studies
1
Principles of RAPD design
All RAPD’s must be designed to "preserve & maintain what remains".
The following principles must be followed when designing partial dentures.
(1) The denture must be passive, i.e. exert no force when not in function.
Otherwise it may act as an orthodontic appliance and cause unwanted tooth
movements.
(2) The denture must be comfortable without comfort it will fail.
(3) The denture must be aesthetically pleasing to the patient. If not, it will
fail.
(4) The design of free-end saddle dentures must compensate for the slight
movement, which occurs during the function to minimise the trauma caused
to the remaining oral structures.
(5) With the above principles in mind, the design should be as simple as
possible. A simple design aids in the maintenance of oral hygiene.
ADVANTAGES OF A RAPD COMPARED TO A FIXED PARTIAL
DENTURE
1.
2.
3.
4.
5.
6.
7.
8.
Help maintain remaining natural teeth in their position (stabilize mobile
teeth).
Easily cleaned-both denture and oral cavity.
Easily repaired or additions made.
Initial cost less expensive than a fixed partial prosthesis.
Enables free-end edentulous area to be restored to function.
Restores lost appearance (aesthetics) and speech (phonetics).
Natural teeth do not have to be prepared
Cost
These notes are now available online
http://randwick.sydneyinstitute.wikispaces.net/Dental+Studies
2
DISADVANTAGES OF AN RAPD COMPARED TO A FIXED
PARTIAL DENTURE
1. May cause damage to supporting tissue and teeth;
Trauma to the gingival margins.
 The denture base fitting too close into the gingival area.
 Food packing between the denture and the natural teeth.
 By the contour of the natural teeth being disturbed by clasps which stop
the flow of food away from them.
2. Cause caries by harboring food. This will depend on the age of the
patient, their oral hygiene and the denture design.
3. Loosen teeth by leverage. This can be caused by the clasps “gripping”
teeth tightly or poor positioning of in direct retention.
4. Traumatised palate. Caused by the denture base movement over the
palate.
ADVANTAGES OF RPI SYSTEM COMPARED TO A LINGUAL PLATE
DESIGN




Less mucosal coverage (comfort)
Aesthetically pleasing (position of I bar)
Less lateral forces on abutment teeth
Self cleansing
These notes are now available online
http://randwick.sydneyinstitute.wikispaces.net/Dental+Studies
3
Advantages of a RAPD compared to an Acrylic RPD.






More rigid
Stronger
Thinner
Choice of many designs
Transfers temperature better
Better fit
Relief wax.
The purpose of relief wax is to make a space between the metal casting and
the mucosa, the reasons this is done is as follows:
 To relieve the bar of the bar clasp from continuously rubbing and
irritating the mucosa.
 To provide retention for the denture acrylic by spacing the mesh of the
casting from the mucosal saddle areas. The space will be filled with acrylic
and therefore no space will be present once the denture is finished.
Outcomes:
You should now be to:
 Identify land marks on a dental model relating to RAPD design
 List the advantages of RPI compared to Lingual plate design
 List the advantages and disadvantages of s RAPD compared to FPD
 List the principles of RAPD design
 List the advantages of a RAPD compared to a Acrylic partial denture
 Explain the purpose of relief wax
These notes are now available online
http://randwick.sydneyinstitute.wikispaces.net/Dental+Studies
4