2. Classification of Partially Edentulous Arches Flashcards
Kennedy Classification System
1) Who? When?
2) Classification
3) Functions to:
1) Who? When?
Proposed by Dr Edward Kennedy in 1925 and improved by supplementary rules of application by Dr Oliver Applegate in 1954.
2) Classification
Divides all PE arches into 4 main classes where the most posterior saddle defines the basic class (except in CIV) and other substantial areas of tooth loss are designated as modification classes.
3) Functions to:
Allow easy visualisation of type of PE
Convenient communication
Facilitates RDP design and treatment planning
Terminology
1) Denture Base Saddle
2) Bounded Saddle
3) Free-End Saddle
1) Denture Base Saddle
The part of a denture that rests on the oral mucosa and to which teeth are attached.
2) Bounded Saddle
An area where a tooth or teeth are missing with abutment teeth are both ends.
3) Free-Ended Saddle
On where there is only an abutment tooth at the anterior end only.
Kennedy Classification System
Class I
Bilateral free-ended or two distal extension saddles with tooth support only at one end of each saddle area.
Kennedy Classification System
Class II
Unilateral free-ended or one distal extension saddle area with tooth support only at on end of the saddle.
Kennedy Classification System
Class III
Unilateral bounded saddle area with tooth support at both ends of the PE area.
Kennedy Classification System
Class IV
A single bounded saddle area anterior to the remaining teeth which crosses the dental midline. Note that there is no modification spaces in this class.
Kennedy Classification System
Applegate’s Supplementary Rules
1) In cases when extractions are to be performed, classification is determined by the state of the arch post-extractions.
2) 8’s are only taken into consideration during classification if they are to be used as abutment teeth.
3) If a 7 is missing and is not to be replaced, it is not considered in classification.
Kennedy Classification System
Modifications
When classifying other PE areas as a part of the basic class, we designate them as ‘mods’. For example, if a right-sided Class II PE patient is also missing the 15 on the left side, then this area is termed ‘mod 1’. If that patient is missing the 15 and 13 on the left side, then this is termed ‘mod 2’ as there are 2 designated modifications.
Other Classification Systems
Joel Friedman’s ABC Classification of RDP Segments (1953)
Classifies arches in 3 basic segment types.
A - Anterior space (PE space involving a tooth/teeth between c9-c9)
B - Bounded posterior space (PE spaces posterior to the c9 but only in
arches with an abutment tooth at the very posterior of the arch)
C - Cantilever posterior space (PE space posterior to the c9 without a
distal posterior tooth.
Each type can further be described as being either discrete (a single missing tooth) or continuous (2+ missing teeth).
Other Classification Systems
Joel Friedman’s ABC Classification of RDP Segments (1953)
Cons
Classification system is based on the ‘natural’ different functions of segments (i.e. incisive function vs posterior masticatory function) However, Friedman assumed that the posterior segment functioned as a single unit and that functional stress was evenly distributed amongst the segment which it is not.
Classification system was also very complex. Classification occurs right to left excluding 8s. Hyphens are used to indicate multiple discrete segments (i.e. Missing 18, 16, 11, 24 = B(16)-A(11)-B(24). Whilst in continuous segments, there is no hyphen (i.e. missing 15-23 = BA space).
Other Classification Systems
Leonard Beckett’s Classifications of RDP cases by Support (1953)
In this classification, the determining factor is how the saddles of a RDP are supported in the mouth.
C1 saddles = Tooth supported (e.g. a bound saddle)
C2 saddles = Tissues supported (e.g. a free-ended saddle)
C3 saddles = Tooth&Tissue supported
Other Classification Systems
Leonard Beckett’s Classifications of RDP cases by Support (1953)
Beckett, like Friedman understood that saddles can come in combinations (eg. could be a C 1&2 or even C123 denture). However, Beckett strived to analyse and design from a functional point of view. He considers:
- Action of muscles of mastication (acts to masticate and protect TMJ)
- Fundamentals of tooth support (asses abutment tooth and it’s perio)
- Fundamentals of mucous support
Other Classification Systems
John Wilson’s Classifications of RDP cases by Support (1954)
Classification, like Beckett’s, tries to go beyond purely descriptive terms and attempts to include evaluation factors that impacts the RDP.
CI saddles = Completely tooth supported with good prognosis
CIIA saddles = Tooth&Tissue supported with abutment at one end only
CIIB saddles = Tissue supported
CIII saddles = Tooth supported with poor prognosis
Other Classification Systems
Prosthodontic Diagnostic Index
Classification system based entirely on the complexity of the individual case: CI = Ideal or minimally compromised CII = Moderately compromised CIII = Substantially compromised CIV = Severely compromised
Diagnostic Criteria is:
- Location and extent of edentulous areas
- Condition of the abutment teeth
- Occlusal scheme
- Residual ridge
