dentures classification

1. DENTURE

2. COMPLETE
DENTURES (CD)
1 A REMOVABLE DENTAL
PROSTHESIS THAT REPLACES
THE ENTIRE DENTITION AND
ASSOCIATED STRUCTURES OF
THE MAXILLA OR MANDIBLE

3. DENTURE BASE: THE PART OF A DENTURE THAT RESTS ON THE FOUNDATION
TISSUES AND TO WHICH TEETH ARE ATTACHED
DENTURE FLANGE: THE PART OF THE DENTURE BASE THAT EXTENDS FROM THE
CERVICAL ENDS OF THE TEETH TO THE DENTURE BORDER
DENTURE BORDER: THE MARGIN OF THE DENTURE BASE AT THE JUNCTION OF
THE POLISHED SURFACE AND THE IMPRESSION SURFACE
DENTURE TEETH: FUNCTIONS OF DENTURE TEETH ARE TO IMPROVE
AESTHETICS, PHONETICS AND MASTICATION.

4. REMOVABLE
PARTIAL
DENTURES
2
IT IS DEFINED AS ANY
PROSTHESIS THAT REPLACES
SOME TEETH IN A PARTIALLY
DENTATE ARCH. IT CAN BE
REMOVED FROM THE MOUTH
AND REPLACED AT WILL – ALSO
CALLED PARTIAL REMOVABLE
DENTAL PROSTHESIS.

5. TWO TYPES OF RPDS
Cast partial dentures
Acrylic partial dentures
THESE ARE MAINLY FABRICATED BY THE
LOST WAX CASTING METHOD AND HENCE
THE NAME. THE TEETH AND DENTURE BASE
ARE MADE OF ACRYLIC RESIN. THESE ARE
OF TWO TYPES:
- CLASP RETAINED – USES CAST METAL
CLASPS FOR RETENTION
ATTACHMENT RETAINED PARTIALS – USES
PREFABRICATED ATTACHMENTS FOR
RETENTION
THESE ARE MADE OF ACRYLIC RESIN WITH
CLASPS OF WROUGHT WIRE. THEY ARE
COMMONLY REFERRED TO AS ‘FLIPPERS’.
THEY ARE ENTIRELY TISSUE SUPPORTED AND
CAUSE GINGIVAL RECESSION WITH LONG
TERM USE. HENCE, THEY ARE COMMONLY
TERMED AS ‘GUM STRIPPERS’ AND SHOULD
BE USED ONLY AS TEMPORARY DENTURES

6. CLASSIFICATION OF
PARTIALLY EDENTULOUS
ARCHES
essential for diagnosing and to arrive at an optimum design or treatment
plan for that specific condition for the rehabilitation of the patients

7. Requirements of classification
1. Should allow visualization of the type of partially edentulous arches being
considered.
2. Should permit differentiation between tooth-supported and tooth–tissue-
supported partial dentures.
3. Serve as a guide to the type of design to be used.
4. The classification should be simple and universally acceptable.

8. based on the relationship of the edentulous spaces to the abutment
teeth

9. Class I: Bilateral edentulous areas located
posterior to the remaining natural teeth

10. Class II: Unilateral edentulous areas located
posterior to the remaining natural teeth

11. Class III: Unilateral edentulous area with natural
teeth both anterior and posterior to it

12. Class IV: Single, bilateral edentulous area located
anterior to the remaining natural teeth

13. Applegate–Kennedy CLASSIFICATION
added two more groups – class V and class VI
Class V: An edentulous
area bounded anteriorly
and posteriorly by natural
teeth but in which the
anterior abutment (e.g.
lateral incisor) is not
suitable for support

14. Applegate–Kennedy CLASSIFICATION
added two more groups – class V and class VI
Class VI: An edentulous
area in which the teeth
adjacent to the space are
capable of total support
of the required prosthesis

15. CLASPS
the most commonly used
extracoronal direct retainer

16. Clasp assembly: The part of a removable dental prosthesis that acts as a direct retainer and/or stabilizer for a
prosthesis by partially encompassing or contacting an abutment tooth-usage.
Clasp: The component of the clasp assembly that engages a portion of the tooth surface and either enters an
undercut for retention or remains entirely above the height of contour to act as a reciprocating element. Generally,
it is used to stabilize and retain a removable dental prosthesis.
Undercut: The portion of the surface of an object that is below the height of contour in relationship to the path of
placement.
Height of contour: A line encircling a tooth and designating its greatest circumference at a selected axial position
determined by a dental surveyor; a line encircling a body designating its greatest circumference in a specified plane.
1.
2.
3.
4.
Definitions

17. COMPONENT PARTS OF A
CLASP ASSEMBLY

18. Retentive arm Retentive terminal
Shouder
Body
a
b
c
THE DISTAL THIRD OF THE RETENTIVE ARM. IT IS THE ONLY
COMPONENT THAT IS PLACED BELOW THE HEIGHT OF THE CONTOUR;
HENCE, IT IS ALSO THE ONLY FLEXIBLE COMPONENT.
THE BODY CONNECTS THE REST AND SHOULDER TO THE MINOR
CONNECTOR. IT CONTACTS THE GUIDE PLANE DURING INSERTION AND
REMOVAL OF DENTURE
IT CONNECTS THE BODY TO THE CLASP TERMINAL. ALSO
PROVIDES SOME STABILIZATION AGAINST HORIZONTAL
FORCES

19. Reciprocal arm

20. MINOR CONNECTOR
JOINS THE BODY TO THE REMAINING
PART OF THE FRAMEWORK

21. TYPES OF CLASPS

22. Types of clasps

23. CIRCUMFERENTIAL CLASP
A RETAINER THAT ENCIRCLES A TOOTH BY MORE THAN 180°, INCLUDING OPPOSITE
ANGLES, AND WHICH GENERALLY CONTACTS THE TOOTH THROUGHOUT THE EXTENT
OF THE CLASP, WITH AT LEAST ONE TERMINAL LOCATED IN AN UNDERCUT

24. CAST CIRCUMFERENTIAL CLASP
• It is also called Akers’ clasp.
• All components of the clasp assembly
are made of cast alloy.
• Retentive terminal should originate
above height of contour and terminate
below it.
• Retentive terminal should point towards
the occlusal surface, never towards
gingival
• The retentive tip should only terminate
in mesial or distal line angle of the tooth,
never in the middle of facial or lingual
surface
• Clasp arm should be kept as low as
possible to gain mechanical advantage
against any lever action on tooth

25. Advantages
1. Easiest to design, construct and repair.
2. Excellent support, bracing and retentive qualities.
3. Most logical choice for tooth-supported removable partial dentures.
4. Causes less food retention.
5. Many types available so can be used in most situations.
Disadvantages
1. More coverage of tooth surface which may lead to decalcification
and/or caries of enamel.
2. Alters the morphology of abutment which affects normal food flow
pattern and can lead to damage of gingival tissues due to lack of
physiologic stimulation.
3. If positioned high on abutment, they can increase the width of
occlusal table which can cause greater occlusal forces to be exerted on
tooth.
4. Difficult to adjust with pliers as with all cast clasps (half round) as
they can be adjusted only in one plane.

26. TYPES OF CAST
CIRCUMFERENTIAL
CLASP

27. SIMPLE CIRCLET CLASP

28. REVERSE CIRCLET CLASP

29. MULTIPLE CIRCLET CLASP

30. EMBRASURE CLASP OR
MODIFIED CRIB CLASP

31. RING CLASP

32. BACK ACTION CLASP

33. FISH HOOK OR HAIRPIN CLASP

34. ONLAY CLASP

35. COMBINATION CLASP
A circumferential retainer for a removable dental prosthesis
that has a cast reciprocal arm and a wrought wire retentive
clasp.

36. It consists of a wrought wire
retentive arm and a cast
reciprocal arm (Fig. 21.87).The
combination of a wrought alloy
and cast alloy gives it the name
‘combination clasp’.
The wrought wire can flex in all
three planes and has greater
flexibility than a cast arm.

37. Advantages
1. Good flexibility – helps dissipate stresses on abutment.
2. Easy to adjust the clasp as it can flex in all planes.
3. More aesthetically acceptable as it can be placed in
gingival third of facial surface – can be used in premolars and
canines.
4. Makes only a line contact with tooth surface and hence
collects less food and is easy to maintain.
Disadvantages
1. Extra lab procedures.
2. Can be easily distorted by careless handling.
3. Poor resistance to horizontal stabilization.

38. BAR CLASP
A clasp retainer whose body extends from a
major connector or denture base, passing
adjacent to the soft tissues and approaching
the tooth from a gingivo-occlusal direction.

39. Indications
1. Small undercut (0.01 inch) existing in
cervical third of abutment
2. Distal extension abutments to
engage a distobuccal (adjacent to
edentulous space) undercut.
3. Most tooth-supported partial
dentures including modification spaces
where aesthetics is a concern.

40. Contraindications
1. Severe tissue undercut.
2. Deep cervical undercut in abutment.
3. Severe buccal or lingual tilt of
abutment.
4. Shallow vestibule.
5. Never used to engage mesiobuccal
undercut of abutment.

41. Advantages
1. Easy to insert and difficult to remove.
2. It is more aesthetic because of its gingival
approach.
3. Variety of bar clasps gives it a wide range
of adaptability.
Disadvantages
1. Tends to collect food.
2. Contributes less to bracing and
stabilization because of its flexibility.

42. TYPES OF BAR
CLASP

43. T-CLASP

44. MODIFIED T-CLASP

45. Y-CLASP

46. I-CLASP

47. BASIC PRINCIPLES
OF CLASP DESIGN

48. THE BASIC PRINCIPLE OF CLASP DESIGN, REFERRED TO AS THE PRINCIPLE OF
ENCIRCLEMENT, MEANS THAT MORE THAN 180 DEGREES IN THE GREATEST
CIRCUMFERENCE OF THE TOOTH, PASSING FROM DIVERGING AXIAL SURFACES TO
CONVERGING AXIAL SURFACES, MUST BE ENGAGED BY THE CLASP ASSEMBLY

49. IN ADDITION TO ENCIRCLEMENT, OTHER BASIC PRINCIPLES
OF CLASP DESIGN ARE AS FOLLOWS
1. The occlusal rest must be designed to prevent
movement of the clasp arms toward the cervical.
2. Each retentive terminal should be opposed by a
reciprocal component capable of resisting any
transient pressures exerted by the retentive arm
during placement and removal. Stabilizing and
reciprocal components must be rigidly connected
bilaterally (cross-arch) to realize reciprocation of
the retentive elements (Figure 7-2).

50. IN ADDITION TO ENCIRCLEMENT, OTHER BASIC PRINCIPLES
OF CLASP DESIGN ARE AS FOLLOWS
13. Clasp retainers on abutment teeth adjacent to distal extension
bases should be designed so that they will avoid direct transmission
of tipping and rotational forces to the abutment.
4. Unless guiding planes will positively control the path of removal
and will stabilize abutments against rotational movement, retentive
clasps should be bilaterally opposed (i.e., buccal retention on one side
of the arch should be opposed by buccal retention on the other, or
lingual on one side opposed by lingual on the other)
5. The path of escapement for each retentive clasp terminal must be
other than parallel to the path of removal for the prosthesis to require
clasp engagement with the resistance to deformation that is
retention.
6. The amount of retention should always be the minimum necessary
to resist reasonable dislodging forces.
7. Reciprocal elements of the clasp assembly should be located at the
junction of the gingival and middle thirds of the crowns of abutment
teeth. The terminal end of the retentive arm is optimally placed in the
gingival third of the crown (Figures 7-4 through 7-6)