This document provides information about a removable partial dentures course taught by Dr. Amal Fathy Kaddah at Cairo University. It outlines the content, objectives, and steps of constructing removable partial dentures. Key steps include diagnostic casts being mounted in centric relation, drawing the ideal removable partial denture design, surveying the diagnostic casts to determine the path of insertion, and revising the design. The components of removable partial dentures are discussed, which include rests, connectors, retainers, and a metal framework with acrylic teeth. Mouth preparation is to be done based on the survey casts and treatment planning.

3. Dr. Amal Fathy Kaddah
Professor of Prosthodontic
Faculty of Dentistry
Cairo University

4. ‫الصخر‬ ‫في‬ ‫تحفر‬ ‫المطر‬ ‫قطرة‬
‫بالتكرار‬ ‫ولكن‬ ‫بالعنف‬ ‫ليس‬

5. Content of the course
Removable Partial prosthodontics
Classification of partially edentulous arches
Consequences of loss of teeth and distribution of forces in the
oral cavity
Objectives, Indications and Contraindications of RPDs
Advantages of RPD over fixed PD
Requirements of RPDs
Forces acting on removable partial dentures
Hazards and damaging effects of improperly designed partial
dentures
Designs of different types of RPDs, biological and
biomechanical considerations during construction of RPDs.
Clinical and laboratory steps of RPDs

6. 1. Examination, Diagnosis and treatment
planning and Primary impression
2. Pouring primary casts and Construction of
special trays.
3. Diagnostic casts mounted in centric
relation
4. Draw the ideal RPD design (on paper)
STEPS OF CONSTRUCTION OF RPD
Clinical and Laboratory steps

7. 5. Transfer the design to the study cast
6. Primary surveying of the casts
7. Revise and finalize the RPD design
8. Mouth and abutment preparation
9. Final impression
10. Pouring master cast
11. Surveying the master cast

8. 12. Drawing the partial denture design on the master
cast.
13. Modification of master cast for duplication.
14. Duplication of the master cast into the refractory
cast.
15. Drawing design on the refractory cast
16. Construction of wax pattern on refractory cast.
17. Sprueing, investing, wax elimination and Casting.

9. 18. Pickling, finishing and polishing
of metal framework.
19. Try-in of the metal frame work on the
master cast and in the patient’s mouth.
20. Jaw relation registration and tooth
selection.
21. Mounting casts on the articulator.

10. 22. Setting-up of artificial teeth.
23. Try-in of the waxed denture.
24. Flasking, processing acrylic resin.
25. Finishing and polishing.
26. Delivery of RPD and final adjustment.
27. Periodic check-up and relining when
necessary.

11. The Component Parts
of Removable Partial Dentures

12. Five Parts of RPD
1. Rests
2. Minor connectors (including
proximal plates)
3. Major connector
Max. Connectors
Man. Connectors
4. Denture base and Artificial Teeth
5. Retainers
Direct retainers
Indirect Retainers

13.  Metal framework: Cr-Co alloy is most commonly used
 Denture teeth: Acrylic or porcelain denture teeth
 Pink acrylic resin

14. Planning sequence for RPDs patients

15. Planning sequence for RPD Patients
Diagnosis, preliminary impression and treatment plan
Diagnostic casts mounted in centric relation
Draw the ideal RPD design (on paper)
Transfer the design to the study cast
Survey the study casts and determine the path of insertion and
withdrawal of the designed RPD, and tripod
Revise and finalize the RPD design

16. Seat and fit the RPD framework
Physiologic adjustment and altered cast impression
if it is extension base RPD
Mouth preparation and impression for the RPD
framework
Maxillomandibular registration (obtain face bow, VDO, and CR
records)
Tooth selection
Wax partial denture try-in if it is esthetic or complex case
Delivery, instructions, periodic recall

17. Diagnosis and treatment plan
• Face bow Record to mount the
maxillary cast
• CJRR– Mounted diagnostic
casts with proper VDO and CR
record
• Occlusal Analysis.

18. Evaluation of diagnostic casts
Diagnostic cast
Accurate reproduction of teeth and adjacent
oral tissues.
Made of stone due to its strength and
resistance to abrasion.
Upper and lower diagnostic casts are
mounted on the articular by:
 Inter-cuspation of the remaining teeth.
 Wax inter-occulsal record.

19. What if patient doesn’t match
articulator?
Articulator
Patient

20. Articulators
mha
aha

21. Articulators
We obtain a measurement of this distance
with a facebow
aha
mha
occlusal errors
The lnterocclusal wedge space will not be equal

22.  Therefore the distance from the condyle to
the teeth is crucial, we obtain a
measurement of this distance with a
facebow

23. Face-bow Function
 Duplicates opening and closing arc of
natural teeth by relating maxillary arch to
the hinge axis.
 Slight change of vertical dimension doesn’t
affect the relation

24. • The first part of the
posterior border opening
is a rotation around the
hinge axis.
 If the terminal hinge axis is recorded on the
articulator using a hinge face-bow, then minor
changes in the vertical dimension will not alter
the horizontal jaw relation.
Face-bow Function

25. N.B.
The face bow records not only the radius from the
condyles to the incisal contacts of the upper central
incisors but also the angular relationship of occlusal
plane to the axio-orbital plane, face bow must be
positioned on the articulator in the same axio-orbital
relation as on the patient.

26. Mounted diagnostic cast help to evaluate:
 Insufficient inter-arch space may be due to:
 Vertical enlargement of the maxillary tuberosity.
 Over-eruption of the posterior teeth which are
unopposed.
 This presents a problem in the placement of artificial
teeth and difficulty in establishing adequate occlusal
plane.
 Inter-arch space

27.  Occlusal plane
 Changes in the occlusal plane of
partially edentulous patients is
expected.
Mounted diagnostic cast help to evaluate:

28. Evaluation of occlusion and articulation of
teeth
 Occlusion should be evaluated:
 In static position during centric
closure
 During excursive movements of the
mandible

29. Evaluation of occlusion and articulation of
teeth
 Occlusion should be examined to:
1. Detect minor occlusal discrepancies in the
form of disharmony between centric relation and
centric occlusion and premature contact between
upper and lower natural teeth.
Treatment:
 Selective spot grinding followed by smoothening
and polishing.
 Crowning of teeth.

30. 2.Evaluate eccentric functional
relations and eliminate balancing
side, working side and protrusive
premature contacts between the
remaining natural teeth.

31. 3. Determine whether the
existing vertical dimension of
occlusion and the existing
centric and eccentric jaw
relations require occlusal
reconstruction.

32. 4. Detect gross occlusal
discrepancies caused by lack of
uniformity of occlusal plane
resulting from multiple over-
erupted teeth which may require
extraction.

33. 5. Determine the space
available for occlusal rests
and artificial teeth.
6. Detect the degree of
anterior teeth overlap

34. Traumatic vertical overlap
Akerly (1977) classified traumatic vertical overlap in to
four basic types:
Type I  Mandibular incisors extrude and impinge into the
palate.
Type II  Mandibular incisors impinge into gingival sulcus of
the maxillary incisors.
Type III Both maxillary and mandibular incisors incline
lingually with impingement of gingival tissues of
each arch.
Type IV  Mandibular incisors extrude into the abraded lingual
surfaces of the maxillary anterior teeth

36. Draw the ideal RPD design(on
paper)
 Any design is a product of
diagnosis, treatment planning
 Abutment, arch and occlusal criteria
 The application of design principles
and philosophy
 A knowledge and appreciation of
RPD biomechanics

37.  Draw the Design of the RPD
on the diagnostic chart.
 Identify the axis of rotation
due to the distal extension
Design sequence:
Rests
Minor connectors
Major connector
Denture base connectors
Retainers
Sort out the proper treatment
sequence

38. RPD design sequence
Draw your RPD design on the study cast
Rests
Proximal plates/Minor connectors
Major connector
Denture base connectors
Retainers
Requires tooth modification

39. What is a removable partial denture
made of ?
 Cr-Co alloy is most commonly
used
 Acrylic or porcelain denture
teeth
 Metal framework:
 Denture teeth:
 Pink acrylic resin

40. How to draw the design
b, Finishing line
a, Rest c: Minor connectors
d: Minor connectors e. Completed Drawing of the design on the study cast: clasps, Major connector and
denture bases

41. 1- Rests and Minor connectors
Occlusal rest is rounded triangular in shape, the base
of the triangle located at the marginal ridge is about one
third to one half the mesiodistal width of the tooth, it is
about 2.5 mm in width,
2.5 mm

42. Cingulum Rest (inverted V Rest)
At the cingulum or just incisal to it.
This is confined to maxillary canines
A rounded inverted V-shaped preparation (half -
moon shaped), on the lingual surface of anterior
teeth

43. Cingulum Rest (inverted V Rest)
• Having 2.5: 3 mm mesiodistal length,
• 2 mm. Labiolingual width and 1.5 mm. in
depth (Fig. 7-25).

44. Usually at the junction of the gingival and
middle one thirds. Having 1.5 mm depth and
2.5 mm width.
Cingulum ball rest
Ball Rest Seat may
prepared in enamel
and in cast
restoration.

45. Canine ledge:
It is a step-like preparation placed on the
mesial or distal halves of the lingual
surfaces of the maxillary canine.
Usually at the junction
of the gingival and
middle one thirds.
Having 1.5 mm depth

46. V-shaped round notch located approximately 1.5
to 2.0 mm from the proximal - incisal angle of the
tooth. Having about 2.5 mm wide and 1.5 mm
deep
Incisal rest:

47. 2. Minor connectors (including
proximal plates)
•Proximal plate must extend 2 mm
onto the tissues
2mm
4-5mm
•Space between the
vertical portions of
minor connectors
should be 4-5 mm.

48. • Space between the horizontal portions of
major connectors and gingival margin
should b 3-4 mm
Rests Minor connectors
2. Minor connectors
3-4 mm

49. If they cross the gingival margin they
should be crossed abruptly and at right
angle to the margin in order to produce
the least possible
soft tissue coverage
2. Minor connectors

50. 3. Major connector
• Should not impair the placement of denture teeth.
• The borders should run parallel rather than
diagonal to the gingival margin.

51. It should be located at least 6 mm away from the
gingival margins and parallel to their mean
curvature
3. Major connector

52. It should cross the midline of
the palate perpendicular to it.
3. Major connector

53. The lateral palatal borders should be
placed at the junction of the vertical
and horizontal surfaces of the palate.
3. Major connector

54. All adjoining minor connectors should
cross-gingival tissues abruptly, and
should join major connectors at nearly a
right angle.
3. Major connector

55. Arrows indicate external finish lines, which
permit butt joint between metal and resin base.
The external finish line should never be placed
directly over the internal finish line
3. Major connector

56. 4. Denture base connectors
Minor connectors forming mandibular
distal extension bases extend posteriorly
about two-thirds the length of the
edentulous ridge.

57. Minor connectors for maxillary distal
extension bases extended to cover the
entire length of the residual ridge
4. Denture base connectors

58. They should be slightly extended
onto the buccal and lingual
surfaces of the ridge
4. Denture base connectors

59. This design adds strength to the acrylic
denture base and helps to minimize distortion
of cured resin bases, which occurs due to the
release of strains after processing.
4. Denture base connectors

60. 5. Retainers
The horizontal extension of the “I” bar
retainer should be at least 2-3 mm from
the gingival margin
2-3 mm

61.  The vertical portion of the “I” bar retainer
must cross the gingival margin at a 90
degree angle
I bar
5. Retainers

62.  The “I” bar retainer must engage the
abutment tooth at the greatest point
of mesial distal curvature
I bar
5. Retainers

63. The clasp should not interfere with normal gingival
stimulation and its terminal should be away from the
gingival margin
The clasp should be designed on biologic as well
as mechanical bases.
3-4mm
Occlusally Approaching clasp
Occlusally approaching clasps

64. Completed preliminary design
Clean, smooth and legible RPD Designs implement:
1- Sharp, smooth outlines in identical color
2- Design outlines proportionately drawn
3- Guide plane tissue contact area clearly marked
4- Specify retention
5- Bead seals clear marked
6- Resin–metal finish lines clearly marked

65.  After Drawing the ideal RPD design
 Survey the study casts and determine the
path of insertion and withdrawal
 Revise the RPD design

66. Mounted diagnostic casts with proper
VDO and CR record
Final RPD design based on
surveying analysis and MAP
Sort out the proper treatment
sequence

67. Mouth preparation
Always use your survey casts as the
blue print of mouth preparation

68. Planning sequence for RPD Patients
Diagnosis, preliminary impression and treatment plan
Diagnostic casts mounted in centric relation
Draw the ideal RPD design (on paper)
Transfer the design to the study cast
Survey the study casts and determine the path of insertion
and withdrawal of the designed RPD, and tripod
Revise and finalize the RPD design

69. Seat and fit the RPD framework
Physiologic adjustment and altered cast impression
if it is extension base RPD
Mouth preparation and impression for the RPD
framework
Maxillomandibular registration (obtain face bow, VDO, and CR
records)
Tooth selection
Wax partial denture try-in if it is esthetic or complex case

70. Surveying Procedure
To identify the most ideal path of
insertion and treatment position

71. This may be divided into the following
distinct phases:
 Preliminary visual assessment of the study
cast.
 Initial survey.
 Analysis.
 Final survey.
Surveying Procedure

72. Eyeballing of the study cast
 Is the stage of Preliminary visual assessment of
the study cast
 Eyeballing of the study cast, by placing the cast
on the survey table and standing directly over it.
The cast is held
in the hand and
inspected from
above.

73. The general form and arrangement of the teeth
and ridge can be observed,
Any obvious problems noted and an idea obtained
as to whether or not a tilted survey should be
employed.
Eyeballing of the study cast

74. Surveying
Dental surveyor
 Instrument used to survey the
abutment and surrounding
structures.
 Most widely used surveyors
Ney and Jelenko.

75. Surveying the diagnostic cast
1) Delineate survey line.
2) Locate teeth undercuts which may be used for
retention.
3) Identify proximal teeth surfaces which can be
made parallel to act as guiding plane.
4) Determine the presence of soft tissue or bone
undercuts.

76. 5) Permit an accurate charting of the required mouth
preparations which include:
 Preparation of proximal tooth surfaces to provide guiding
planes.
 Reduction or disking of tooth structure to eliminate
interferences.
 Modifying tooth contours to permit acceptable location of
the reciprocal and retentive clasp arms.
 Surgical removal of bone or soft tissue interferences.

77. 6) Select the most suitable path of insertion which:
 Allows easy placement of the prosthesis.
 Avoids impingement of oral mucosa.
 Provides the best esthetic appearance.
 Provides adequate clasp retention.
7) Recording the position of the cast in relation to the
selected path of insertion for repositioning of cast on
the surveyor by tripoding or scoring.

78. Tripoding
 Placing three widely separated
marks on tissue surface of the
cast lingual to the remaining teeth
while the cast and the vertical arm
of the surveyor are held at fixed
vertical height, to establish three
points on the same horizontal
plane, made by tip of carbon
marker.

79. Scoring
 Consists of scoring the two sides
and the dorsal aspect of the base
of the cast with sharp instrument
held against the surveyor blade.
 By tilting the cast until all three
lines are parallel to the surveyor
blade, the original tilt can be re-
established.

80. Treatment of irritated soft tissue
Periodontal treatment
Preprosthetic surgery
Endodontics
Orthodontics
Restorative
Treatment partial
Teeth preparation
and impression for
the RPD framework
Diagnosis and treatment plan
Pt. may
requires

81. Next lecture
Mouth Preparation

82. Thank You
and Good
Luck

83. Mouth Preparation
 Mouth Preparation, Follow the Preliminary
diagnosis , and the development of a tentative
treatment plan.
Objectives:
 To Return the mouth, to the optimum health, and
eliminate any condition, that would be
determinable to the success of the removable
partial denture.

84. Mouth Preparation include Procedures in
five categories:
1- Periodontal preparation.
2- Restorative preparation.
3- Preprosthetic surgical preparation.
4- Treatment partial denture
5- Preparation of abutment teeth.
Mouth Preparation

85. Objectives
1- Removal and control of all the Etiological
Factors contributing to periodontal disease
2- Elimination or reduction of all pockets.
3- Establishment of functional non traumatic
occlusion.
4- Development of personalized plaque control.
Periodontal Preparation

86. Lack of positive rests results in prosthesis displacement,
which can destroy mucosa & periodontal attachment
(100% mucosal support)
Treatment of Irritated Soft Tissue
1. Ill-fitted Existing prosthesis,
2. Lack of positive rests,
3. Hyperocclusion
4. Bacterial and fungal
infections
Causes:

87. Irritated and traumatized soft tissue
Treatment of Irritated Soft Tissue

88. Tissue conditioning
treatment
Fabrication of well design
partial
Adding positive rests to control the
relationship of prosthesis to mucosa
Solution:
Treatment of Irritated Soft Tissue

89. Restorative and Fixed Preparation
Crowns to restore remaining teeth are often
necessary and are contoured to coordinate and
integrate with
RPD treatment.
Note positive rests.

91. Oral Surgical Preparation
1. Extraction, Removal of residual roots, Impacted teeth, Malposed tooth.
2. Cyst and odontogenic tumors.
3. Exostoses and tori.
4. Hyper plastic tissues.
5. Muscle attachment and frena.
6. Bony spines , and knife edge ridges.
7. Polyps, papilloma, traumatic hemangiomas.
8. Hyper kera tosis, erthyroplakia, and ulcerations.
9. Dento facial deformity.
10. Osseo integrated device.
11. Augmentation & alveolar bone
12. Conditioning of abused and irritated tissue by the use of tissue conditioning mat.
- As early As Possible; long time interval Between surgery
and RPD construction.

92. Removal of Residual Roots
Impacted teeth
Preprosthetic Surgery
Extraction

93. Large Tori
Gross bone undercut
Enlarged tuberosity
Preprosthetic Surgery

94. Osseo-integrated device

95. Implant supported prosthesis
 Implants in the posterior region of the
mandible to decrease the residual ridge
resorption

96. An acrylic resin
partial denture that
is placed on interim
or transitional
bases
Treatment Partial Denture:

97. Indications:
1. Cases require restoration
of vertical dimension
2. Immediate esthetic &
functional needs
3. Evaluation of hygiene &
abutments
4. As immediate extraction
site bandage
#23 & 26: hopeless teeth
Extraction is recommended
Immediate treatment partial in
place right after extraction

98. Next lecture
Abutment
Preparation

99. Thank You
and Good
Luck

102. Mouth and abutment preparation
Dr. Amal Fathy Kaddah
Professor of Prosthodontic
Faculty of Dentistry
Cairo University
Abutment preparation

103. Planning sequence for RPD Patients
Diagnosis, preliminary impression and treatment plan
Diagnostic casts mounted in centric relation
Draw the ideal RPD design (on paper)
Transfer the design to the study cast
Survey the study casts and determine the path of insertion
and withdrawal of the designed RPD, and tripod
Revise and finalize the RPD design

104. Seat and fit the RPD framework
Physiologic adjustment and altered cast impression
if it is extension base RPD
Mouth preparation and impression for the RPD
framework
Maxillomandibular registration (obtain face bow, VDO, and CR
records)
Tooth selection
Wax partiaal denture try-in if it is esthetic or complex case
Delivery, instructions, periodic recall

105. Which bur is used for what ?
• Round diamonds for occlusal
rest seats in sound enamel
• Bud finishing burs for rest
seats in amalgam
• Diamond wheel for cingulum
rest seats
• Straight diamond for guide planes and recontouring
• Sandpaper discs and rubber points for polishing

106. ‫لم‬‫ا‬

107. Reshaping of Abutment Tooth
1. Occlusal plane adjustment.
2. Parallel Guiding Surfaces (Guiding planes)
3. Adequate interproximal clearance for Minor
Connectors
4. Rest Seat preparation (Sensitivity in rest preparations
>> Placement of restorations)
5. Changing the height of contour to improve clasp
location
6. Creation of retentive areas on abutment teeth.
7. Abutment coverage with crown restoration.

108. 1. Correction of occlusal plane
1- Unopposed teeth for a long period of
time >> over Eruption.
Minor over Eruption
>> Recontouring the surface of the tooth.
Moderate >> cast restoration,
e.g. onlays or crowns.
If Extreme >> Extraction.

109. b. Supraeruption accompanied
by down ward migration of
tuberosity
1. Correction of occlusal plane

110. c. Tipped molar
1. Correction of occlusal plane
Minor >> Recontouring
Moderate >> Cast restoration
e.g. onlays or crowns
If Extreme >> Extraction

111. 1. Correction of occlusal plane
Extended occlusal rest
Additional occlusal rest
distally
c. Tipped molar

112. Provision of support for periodontally
weakened teeth
Teeth showing decreased periodontal support
would require splinting.
Reasons for splinting.
To provide adequate support,
and stabilization for a RPD.

113. Types of splinting
Fixed splinting
Designing of the RPD
to join the teeth as a functional unit.

114. Fixed Splinting.
By joining teeth with Fixed restoration >> provide
resistance to antero- posterior forces but not
medio lateral forces.
To resist medio lateral forces, splinting should
include one or more anterior teeth.
Disadvantages Closure of inter proximal Contacts
complicates Oral hygiene measures
Provision of support for periodontally
weakened teeth

115. Splinting by using properly designed RPD
 Swing lock Removable partial denture leads
to an even distribution of applied force.
 Extended arm Clasp.
 Kennedy bar.
 Lingual Plate.
Fixed or Removable splinting?
Provision of support for periodontally
weakened teeth

116. Reestablishment of arch continuity
 Lone – standing tooth adjacent to an extension
base area is termed a pier abutment.
 Placing a clasp on such a tooth leads to
periodontal destruction and abutment loss.
 An appropriately constructed fixed
partial denture is used to reestablish
arch continuity.

117. Reshaping or Recontouring the abutment tooth
 Enameloplasty
 Reshaping or Recontouring, But not over
cutting. Must be confined to Enamel surface,
other wise consider the properly contoured
crowns.

118. Recontouring
• The contours of the natural teeth most often require
adjustments for the proper placement and
functioning of the RPD.
Recontouring may be required to
1. Improve the occlusal plane by grinding of the cusp tips
and incisal edges of anterior teeth.
2. Create guiding plans
3. Improve survey lines (improve clasp location)
4. Improve clasp retention (dimpling)

119. a. Proximal surfaces for guiding
plates
b. Lingual and palatal surfaces for
reciprocal arms and major
connectors
2-Parallel Guiding Surfaces
They are parallel surfaces on

120. Guiding planes
Guiding plane adjacent to a tooth supported
segment should extend vertically 2 to 4 mm
occluso-gingivally, and should be kept as far from
the gingival margin as possible
2-4mm

121. ½ mm
depth
It should be produced by removing a minimal and fairly
uniform thickness of enamel, usually not more than
0.5m.m., from around the appropriate part of the
circumference of the tooth.

122. Proximal plates (guiding Plates)
The bucco-lingual width of the proximal plate is
determined by the proximal contour of the tooth

123. Functions of guiding plates
 Bracing, stability and
retention
 Facilitate easily insertion
and removal of the
denture.

124. Guiding plate contact the whole length of the
guiding plane in bounded saddle case.
Bounded
cases
G Plane
G Plate
Tip of the G. Plate Contact approximately 1 mm of
the gingival portion of the guiding plane in distal
extension cases

125. 1/3
1/3
1/3
Tip of the GP Contact approximately 1 mm of the gingival
portion of the guiding plane in distal extension cases. a slight
degree of movement of the base and the clasp is permitted
without transmitting torsional stress to the tooth
Clasp Disengage Vertically with
extension base loading.
Free end
Saddle

126. Proximal plates (guiding Plates)
The proximal plate together with the
mesiolingually placed minor connector provides
stabilization and reciprocation of the assembly
lingual view

127. Initial contacts on the
abutment teeth
Continuously follow the same path
guided by the proximal plates
Parallel guiding surfaces Terminal resting position
Insertion of RPD:
Follow the designed
line of draw
(path of insertion)
More important parallel to the
path of insertion and removal.

128. b. Lingual and palatal surfaces for
reciprocal arms and major connectors.

129. If some of the abutment teeth
surfaces are flat and parallel to the
path of insertion, they will act as
guiding planes and the passage of
the denture into place will take
place smoothly
Guiding planes

130. Guiding planes

131. Remember:
A partial denture should have a
single path of insertion this is only
possible for dentures with bounded
saddles
For dentures with free-end saddles 2
or more paths of insertion will be
possible

133. Surveying & Tripoding >> Cast orientation
- anterior-posterior(affecting proximal surfaces)
- Anterior-posterior (affecting parallel guiding surfaces)
- Left-right (affecting retention areas)

134. Prepare Parallel Guiding Surfaces:
Use parallel-sided bur
Diamond:
For tooth/or porcelain
Carbide:
For tooth

135. Preparation of Guiding Planes
Prepare parallel guiding surfaces using parallel sided burs
½ mm
depth

136. Guiding surfaces are prepared first, as determined by
the path of insertion
Parallel Guiding Surfaces
Preparation guide indicating the designed
to facilitate tooth alteration
Follow the natural
Curvature of the tooth

138. When prepare parallel guiding surfaces
of anterior abutment----
Stay on the lingual half to optimize esthetics !

139. Minor Connectors
It is the part of the partial
denture, that connects units of
the prosthesis with either the
major connector or the
denture base.
Minor connectors

140. 3- Adequate Clearance
for Minor Connectors
Tooth Preparation for RPD
.1
Parallel Guiding Surfaces

141. Finish and polish all the alteration
areas

143. Mouth Preparation
 Mouth Preparation, Follow the Preliminary
diagnosis , and the development of a tentative
treatment plan.
Objectives:
 To Return the mouth, to the optimum health, and
eliminate any condition, that would be
determinable to the success of the removable
partial denture.

144. Mouth Preparation include Procedures in
five categories:
1- Periodontal preparation.
2- Restorative preparation.
3- Preprosthetic surgical preparation.
4- Treatment partial denture
5- Preparation of abutment teeth.
Mouth Preparation

145. Reshaping of Abutment Tooth
1. Parallel Guiding Surfaces (Guiding planes) 2.
Adequate clearance for Minor Connectors
1. Rest Seat preparation and occlusal
adjustments.
2. Sensitivity in rest preparations ( Placement of
restorations).
3. Changing the height of contour and Creation of
retentive areas on abutment teeth.
4. Abutment coverage with crown restoration.

146. Tooth Preparation for RPD
1. Parallel Guiding Surfaces
2. Prep. For Minor Connectors
3. Rest Seats
Mark the existing centric and excursive contacts with
articulating paper prior preparation
Avoid removing centric contacts when possible
Avoid creating undercuts in preparation
Check the rest prep thickness with baseplate wax
intraorally at both centric and excursive .

147. The buccal cusps of the mandibular posterior teeth and
lingual cusps of maxillary teeth are called supporting
cusps.
These cusps occlude in central fossa and maintain the
occlusal vertical height.
They also called centric cusps and holding cusps.

148. A- Occlusal Rest
Rest is any unit of a partial denture that
rests upon a tooth surface to provide vertical
support for the denture.

149. Posterior Rests #4/or #6/or
#8 round bur
A- Occlusal Rest

150. Rest Seat
The Marginal Ridge Is Lowered Approximately 1 to
1.5 Mm of Teeth in Relation to a Vertical Line
(permit sufficient bulk )
1mm

151. The floor of the rest seat
should be spoon shaped
Rest Seat

152. Spoon Shaped floor Inclined Apically As It
Approaches the Center of the Tooth
1mm
Rest Seat

153. Spoon shape and not raise the
vertical dimension

154. A high survey line on a tooth that is to be clasped is
unfavorable because it requires the clasp to be
placed too close to the occlusal surface and may
create an occlusal interference (arrows).
Even if an occlusal interference is not present, a
high clasp arm is more noticeable to the patient and
may interfere with mastication.

155. Where there is no space occlusally for it to do so,
The preparation must be extended as a channel on to
the buccal surface of the tooth.
In some circumstances it may also be necessary to
reduce and recontour the cusp of the tooth in the
opposing arch.

156. Rest prep on existing Metal crown:
Diamond bur only
Always inform the patient in advance the
potential risk of perforating the existing
crown/or restoration

157. Rest seats on posterior teeth
 The rest should be at least 1 mm thick for
adequate strength.
 To check that sufficient enamel has been
removed Use a strip of softened pink wax.

158. The patient should be asked to occlude on a
strip of softened pink wax. The thickness of
wax in the region of the rest seat will
indicate if adequate clearance has been
achieved

159. Placing the rest on the surface of the
tooth away from the saddle >>> decrease
torque on the abutment tooth when
vertical forces are applied
How ???? 6 adv .

160. Special Considerations
1- Boxed shaped occlusal rest
•Induces forces
on the abutment
??????
•The use of a box-shaped rest seat
within a cast restoration may result in
the rest applying damaging horizontal
loads on the abutment tooth.
•These rest seats should be restricted to
tooth-supported dentures where the
periodontal health of the abutment
teeth is good.

161. Special Considerations
1- Boxed shaped occlusal rest
•Provide Guide-surfaces
•Employed Only on a Perfectly
Periodontally Healthy Tooth
•Helps in Preventing Lateral
Movement of the Denture
•It Provides Increased Denture Retention

162. 2-Tipped Molar (Mesially
Inclined Mandibular Molar)

163. a- An Additional Occlusal Rest in
the Distal Fossa

164. b- Molar With Rest Preparation Extended
From Mesial Marginal Ridge to Distal
Triangular Fossa

165. Extending the occlusal rest over the center of the
mesiodistal fissure, allows for the transmission of the
vertical load over the whole occlusal surface and
directs the forces along the long axis of the tooth.

166. Onlays on multiple abutments and joined
together during casting to help in splinting
periodontally weak teeth.

167. 1- Lingual Rests
2. Incisal Rest
3- Embrasure Hooks
A- Occlusal Rest
Rests
B- Anterior Rest

168. B. Anterior Rest Seats
Cingulum rest
Incisal rest
Circular concave rest

169. 1-Lingual Rests
a- Cingulum Rest (inverted V Rest)
b. Ball Rest
c. Canine Ledge

170. a- Cingulum Rest
(inverted V Rest)
All sharp angles and
undercuts should be
eliminated.

171. Lab
Ling
M D
2 mm
1- 1.5 mm
Half -Moon Shaped = V- Shaped
A

172. Rest seats on anterior teeth
A cylindrical diamond stone with a rounded tip
should be used to prepare the rest seat. A
spherical instrument tends to create unwanted
undercuts.

173. If Amalgam or cast restorations are used to cover exposed
dentin.
1- Flamed shape bur at 45° to create an outline form
2. Inverted cone shape bur to create the positive rest seat
3- Then roundation with a cylindrical diamond stone with a
rounded tip.

174. Cingulum rest is rarely satisfactory on
mandibular anterior teeth due to inadequate
thickness of enamel.

175. The rest seat is broadest at the
center and as it approaches the
proximal surfaces it merges
with the normal anatomy of the
tooth.

176. Create an occlusal interference
Interfere with mastication.

177. Properly designed cingulm
rest on the canine, prevents
movement of the rest in a
gingival direction and
maintains tooth position.

178. Rest Seat may prepared in enamel
or in cast restoration

179. b. Ball Rest
No sharp line angles
1.5 mm Deep - 2.5 mm Wide

180. Anterior Circular Concave
Rests: #2/or #4 round burs

181. Circular concave rests
Diamond burs for
prep on porcelain and
tooth
Carbide burs for
prep on tooth
&metal

182. Check the clearance for the rests
both centric and excursive position
Minimum rest thickness: 1 mm
Circular concave rests

183. C. Canine Ledge
1.5 mm Deep
No Sharp Line Angles
A Step-like Preparation

184. It is a step-like preparation placed on
the mesial or distal halves of the
lingual surfaces of the maxillary
canine.
C. Canine Ledge

185. Usually at the junction of the
gingival and middle one thirds.
Having 1.5 mm depth.
C. Canine Ledge

186. * The ledge rest seat should be
perpendicular to the long axis of the
tooth. All undercuts and sharp line
angles should be avoided.
C. Canine Ledge

187. Lingual Rests
c. Canine Ledge
a- Cingulum
Rest (V Rest)
b. Ball Rest

188. 2- Incisal Rest
•Used predominantly as auxiliary
rests or as indirect retainers
•Rigid extension
•More applicable on
mandibular teeth
•2.5 Mm Wide and 1.5 mm Deep

189. 2mm
1.5mm
Incisal Rest seat

190. Incisal Rests: Flamed shape bur
Positive Incisal Rest:
1. Two Planes Preparation:
Incisal Plane
Labial Plane
2. Concave MD, Convex BL
3. 1/3 of MD Incisal Width
Incisal Plane Labial Plane

191. Incisal Rest Seat Preparation

192. Tooth Preparation for RPD
1.Parallel Guiding Surfaces
2. Minor Connectors
3. Rests
4.Retainer area
Tooth alteration to lower
the height of contour
Excessive
retention
 inadequate retention
Create a “dimple” retention
area by enamoplasty
Crown the tooth

193. How can undercuts be created ?
• Dimpling
– But needs to be done with extreme caution
(remember the thickness of cervical
enamel)
• Addition of composite
– How long will it last ?
• Cast restorations
– Ideal contours can be created

194.  ‘Dimpling’ to create an undercut

195. Enhancing Retentive
undercuts

196. Recontouring or Reshaping
Adjustments of the contours
of the natural teeth for the
proper placement and
functioning of the RPD.
in Summary

197. Reshaping of Abutment Tooth
1. Occlusal plane adjustment.
2. Parallel Guiding Surfaces (Guiding planes)
3. Adequate interproximal clearance for Minor
Connectors
4. Rest Seat preparation Sensitivity in rest preparations
(Placement of restorations)
5. Changing the height of contour to improve clasp
location
6. Creation of retentive areas on abutment teeth.
7. Abutment coverage with crown restoration.

198. Sequence of the procedures
 Occlusal adjustment
 Guide planes- Must be done before
rest seats
 Rest seats
 Creation of undercuts – Occasionally

199. Finally !
 Remember time and care
spent on tooth preparation
will save a lot of time and
problems later

200. Reshaping of Abutment Tooth
1. Parallel Guiding Surfaces (Guiding planes)
2. Adequate clearance for Minor Connectors
3. Rest Seat preparation and occlusal adjustments.
4. Sensitivity in rest preparations ( Placement of
restorations).
5. Changing the height of contour and Creation of
retentive areas on abutment teeth.
6. Abutment coverage with crown restoration.

201. Mouth Preparation for Combination Cases
For cases require fixed and removable restorations it is necessary
to have the final RPD design, guiding surface preparation, and
denture teeth trial set-up before you start the restorative work
To optimize the shade matching, orientation of the plane of occlusion
, developing proper scheme of occlusion, and create ideal parallel
guiding surfaces of the restoration with reference to natural dentition

202.  Correct the occlusal plane
 Occlusal equilibration to establish fully
balanced occlusion
 Design the mandibular RPD & surveying
Determine the path of insertion
Fixed Technique Model

203.  PFM preparation and Wax-up
- Full contour wax-up first
- Shaping the full contour wax-up to
provide proper rest, parallel guiding
plane, and proper retention area
Fixed Technique Model

204. Adequate Occlusal
Reduction
at both centric and excursion
Rest & Finishing Line
Proper Axial Reduction
Checklist of #30 PFM prep

205. Apply die hardener
& wax separator before
the wax-up

206. Centric: Even cusp-fosse or cusp-marginal
ridge contacts
Eccentric: Fully balanced occlusion
Full contour wax-up
• Occlusion
• Contour
• Morphology

207. Facial & Lingual Contours:
Flatly convex contour and harmonize with
adjacent teeth
Full contour wax-up
• Occlusion
• Contour
• Morphology

208. Properly fluted contour at the bifurcation area
of the molar to allow the hygiene access and
the flow pattern
Full contour wax-up
• Occlusion
• Contour
• Morphology

209. Morphology:
Cusps, triangular ridges,
central groove and
supplemental
ridges & grooves
Full contour wax-up
• Occlusion
• Contour
• Morphology

210. Checklist of Wax Pattern for RPD Abutment
Parallel Guiding Surface(s): Curvilinear Concept
Clearance for Rests & Minor Connector
Wax Pattern Position in relation to soft tissue
Retention and Reciprocation

211. Shape off the mesial bulge with wax knife
To provide the parallel guiding surface => curvilinear
shape
Checklist of Wax Pattern for RPD Abutment

212. Parallel Guiding Surface(s): Curvilinear Concept
Clearance for Rests & Minor Connector
Checklist of Wax Pattern for RPD Abutment

213. Inspect the lingual contour with diagnostic rod
to avoid excessive bulge in related to the soft tissue
Parallel Guiding Surface(s): Curvilinear Concept
Clearance for Rests & Minor Connector
Wax Pattern Position in relation to soft tissue
Checklist of Wax Pattern for RPD Abutment

214. 0.0”
.01”
B
L
Keep the height of
contour low for placement
of reciprocation clasp
(non-retentive)
Inspect the lingual contour with .01” undercut
gauge to ensure we provide adequate retention
on the cervical 1/3 of the crown for active I-bar
Checklist of Wax Pattern for RPD Abutment
Retention and Reciprocation

215. Remove the wax crown from the
cast
Inspect the thickness through the light
Final Check

216. Tooth preparation for FPD:
Adequate reduction for FPD material
Retention & Resistant Form
Follow the same line of draw

217. To seat the FPD following one line of draw

218. Insertion of RPD:
Follow the designed line of draw
(path of insertion)
Initial contacts on the abutment teeth

219. What we do for
others counts
most in life...
Be Alert to give
Service.....

220. Thank You
and Good
Luck