Support Flashcards
saddle
edentulous area
replaces gaps but not necessarily teeth numerically
denture base
connector
flange
replacement tissue extending to vestibular sulcus
- extension from alveolar ridge into buccal or labial sulcus
7 questions to ponder when designing an RPD
Will a prosthesis be made?
- Are they dentally fit to cope? Alternative treatment options?
What type of prosthesis: Fixed or removable?
What teeth will be replaced and why?
- Patient’s expectation is to replace all missing teeth – but will fill gaps but not necessarily numerical value
- What saddles will be restored
How will occlusal loading be resisted by the denture?
- Tooth; Mucosa; Tooth & mucosa
How will the denture be retained?
How the denture will resist horizontal movement
How will the components be joined?
What is Kennedy Classification?
an anatomical classification that describes the number and distribution of saddle (edentulous) areas.
- The most posterior saddle defines the classification
Number of saddle areas present in patient (not number of missing teeth)
third molars in Kennedy classification
third molars are generally ignored unless they play a direct part in the denture design
Kennedy Classification: Class I
bilateral free-end
- arch with 2 free end saddles
Kennedy Classification: Class II
unilateral free-end
- 1 free end saddle on arch
Kennedy Classification: Class III
unilateral bounded
- abutments either side
Kennedy Classification: Class IV
anterior bounded (crossing the midline) - abutments either side of the midline e.g. canine to canine (2 to 2 missing)
what is each additional anterior saddle classification referred to as?
a modification
e. g. if a case had two bounded saddles present it would be classified as a ‘Kennedy Class III modification 1’.
- Do not include classifying saddle in classification
Kennedy Class IV cannot be modified.
- As most posterior saddles determines classification
can Kennedy Class IV be modified?
no
As most posterior saddles determines classification
support
term used to describe the RESISTANCE of a denture to OCCLUSALLY DIRECTED Load
Resistance to vertical seating forces
- E.g. chewing forces
2 options for resisting movement towards the tissue are
- Utility of hard tissue
Teeth long axis via PDL - Spread the load over large surface area
E.g. palate
Teeth in support
prevents/resists movement, directs load through periodontal ligaments of adjacent teeth
- into alveolar bone, natural spread
mucosa in support
Needs large surface area = load distributed over a wide area (Stiletto Heel vs Snow Shoe)
- Through the saddle area or hard palate themselves directly onto alveolar bone
Don’t want a small area of load directly onto bone as accelerate bone resorption in that area
Craddock Classification of Support provides
Craddock provides a simple classification based on support for a removable partial denture.
- Describes how the denture on saddle areas is supported
It only gives the type of support and does not tell anything about the number or distribution of teeth.
3 classes of Craddock Classification
- tooth
- mucosa
- tooth & mucosa
tooth support
Teeth provide a HARD tissue resistance to occlusal loading
- Down through long axis onto PDL into bone
- Added root area gives wide distribution of load
Common for bounded saddles
mucosa support
A LARGE coverage provides resistance to occlusal loading
- Doesn’t involve abutment teeth at all, uses the residual alveolar ridge and all the hard palate (need large denture base)
tooth & mucosa support
A combination of HARD tissue and LARGE coverage when there are reduced number of teeth and large edentulous saddles.
e.g. Free end saddle (cannot avoid abutment loading but can use mesial abutment tooth)
5 positives of tooth support
Transmits load via the periodontal membrane.
- Down onto PDL not compressing tissue
Allows the supported denture base to feel like the natural dentition.
Is more comfortable for the patient.
Protects the soft tissue from trauma.
Is likely to stay in close contact with its supporting structures over a period of time.
- Less spacing
2 downsides of mucosa only support
Must cover as large an area as possible.
- Reduction of the occlusal table
- Denture needs to be larger than it potentially could be
Allows the denture base to move slightly. Sink into the mouth – more conscious for the patient
- Possible damage to adjacent gingival margins
what should be the first considered option for support for an RPD?
tooth support
what are the best teeth for providing support?
those with the largest root area depending on the health of the periodontal attachment.
what does root surface determine?
how much load the tooth can take in addition to itself
A healthy tooth can potentially carry its own load plus one and a half similar teeth
- E.g. molar can carry premolar