SlideShare a Scribd company logo
1 of 70
Major and Minor Connectors,
Rest and Rest Seats, and
Direct and Indirect Retainers
Ammar G. Salem KHBMS 4th Year
Major Connectors
They unit the major parts of the RPD framework
prosthesis
It provides cross-arch stability to help resist
displacement by functional stresses
Should not
substantially alter
the natural
contour of lingual
surface or palatal
vault
It should be
uniform for better
stress distribution
Guidelines Regarding Major Connector
Rigidity Relief
Uniformity Contour
Flexible Major
connector is
ineffective and
detrimental
Avoid impinge on
gingival tissue,
bony or soft
tissue prominence
01 02
04 05
Should not
contribute to food
trapping
Design
Cleansing
Reuqire proper
shape, thickness
and location
03
06
Mandibular Major Connectors
Lingual Bar
Linguoplate
Sublingual Bar
Lingual Bar with Cingulum Bar
Cingulum Bar
Labial Bar
Lingual Bar
Most common used.
● Cross-section is half pear shaped.
● Tapered superiorly and bulk inferiorly.
● Recommended placement as inferior as
possible.
It is recommended that superior border is
minimum 4mm below gingival margin.
Linguoplate
Need terminal rest at each end.
It should be contoured to follow nature of teeth
and embrasures.
Overlapped teeth need lingual proximal surfaces
recontouring.
● High frenum attachment, slightly elevated
floor.
● Class I with excessive vertical resorption.
● Stabilization of periodontally weakened teeth.
● When future replacement is expected.
Design of Mandibular Major Connectors
Step 4
Connect basal seat
area to inferior and
superior borders of
major connector and
add minor connectors
to retain acrylic resin
denture base.
Step 2
Outline the inferior
border of major
connector
Outline the superior
border of major
connector
Step 3
Step 1
Outline basal seat
areas
Cingulum Bar and cingulum with lingual
bar
when Linguoplate indicated but lack axial
alignment of anterior teeth, in case of excessive
block-out of interproximal undercuts must be
made.
● Located slightly above or on cingula.
Acceptable esthetic in wide diastema than
Linguoplate.
Labial Bar
In case of extreme lingual inclination of remaining
lower premolar and incisor teeth.
● Can be avoided by recontouring or reshaping
by means of crowns.
Also when lingual tori is inoperable.
Swing Lock Design
Consist of labial bar connected to major
connector by a hinge at one end and a latch at the
other end and supported by multiple rests and
stabilized by Linguoplate and retention by struts.
● Contraindicated in: poor oral hygiene, lack of
plaque control, shallow labial vestibule, high
frenum.
● Indicated in missing key abutments (canine),
unfavorable tooth and soft tissue contours,
teeth with questionable prognosis.
Maxillary Major Connectors
Single palatal strap
Combination anterior and
posterior palatal strap
Palatal plate
U shaped plate
Signle palatal bar
Anterior posterior palatal bar
Single palatal strap
In bilateral tooth supported particularly when short
spaces are posteriorly positioned.
In Class II with cross-arch attachment by
extracoronal retainers or internal attachments.
Anterior-Posterior palatal Strap
Almost any design of Class II and Class IV
● Anterior component better to avoid rugae
coverage, posterior to crest or in the valley.
● Posterior component should be flat, minimum
width 8mm, avoiding tongue interference and
anterior to vibrating line.
● Should form square, rectangular form.
Palatal Plate
Require anatomic replica and uniform thickness.
● Used in Class I when last abutment is canine
or 1st premolar with excessive vertical ridge
resorption.
● Two or more edentulous areas.
In form of complete plate or partial plate.
Palatal Plate
Design of Maxillary Major Connectors
Step 1 Step 2
Outline primary
stress bearing areas
Outline non-bearing
areas
Step 3
Outline connector
areas
Step 4 Step 5
Selection of
connector type
Unification
U-shaped Palatal Connector
Least desirable.
● In case of large inoperable torus and
replacement of multiple anterior teeth.
It lacks rigidity, fail to support well, and bulkiness
hinder the tongue.
Should be supported by rests and being away
from gingival tissue.
Single Palatal Bar
Highly objectionable.
Need bulk and being centered.
Minor Connectors
They connect the major connector to other
components of framework.
(prosthesis to abutment function): transfer
functional stress to abutment teeth and
underlying tissue.
(abutment to prosthesis): transfer effect of
components throughout prosthesis.
Minor Connector: form and location
Bulk Convex surface
For rigidity
When contacts axial
surface of abutment
In embrasure
For tongue
interference
Pass vertical Tapering
Should cross abrupt
Toward contact area
junctions should be strong butt joint without much bulk.
Angle not more than 90 degrees.
Open latticework/ladder type is preferred.
On mandible extending 2/3rd length of residual ridge,
while on maxilla extending entire length.
On mandible should extend buccally and lingually to
minimize distortion of resin during processing.
Denture base minor connector
• Integral part for retention of acrylic resin bases.
• Provide stability for framework during transfer and
processing.
• Prevent distortion during resin processing.
Tissue Stop minor connector
• Medial extent depends on later extent of major
connector.
• Too far medial position alter the natural contour.
• Too far buccal position make difficult to create
natural contour of acrylic resin on lingual surface
of artificial teeth.
• Best line is 2mm medial to imaginary line
contacting lingual surfaces of missing posterior
teeth.
Finishing Lines of minor
connector
Rest and Rest Seat
Any component that provide vertical support on
tooth surface for denture.
Must be rigid
Can be:
Occlusal – Lingual - Incisal
Occlusal Rest
● Conventional.
● Extended.
● Interproximal
● Internal
Guidelines
● Outline rounded triangular
with apex toward center of
occlusal surface.
● The base at marginal ridge
at least 2.5mm.
● Lower marginal ridge to
permit bulk of metal (1.5mm)
● Floor seat should be apical
to marginal ridge, concave
spoon shaped.
● Angle between rest and
vertical minor connector not
less than 90 degrees.
Extended occlusal rest
Recommended in Class II modification 1 and Class
III where most posterior abutment is mesially
tipped molar.
● > half of mesiodistal width.
● 1/3rd of buccolingual width.
● Minimum 1mm thickness of metal.
Purpose to minimize tipping and ensure forces to
long axis of abutment.
Interproximal occlusal rest
Similar to occlusal rest seats with exception of
lingual extension.
● Avoid reducing or eliminating contact points.
● Analyze possible interocclusal interference.
● Avoid creation of vertical groove.
Internal occlusal rest
Entirely supported by cast retainers.
● Provide support and stabilization.
● Form parallel to path of insertion, slightly
tapered occlusally, and dovetailed.
● Only for tooth supported RPD.
Eliminate visible clasp arm buccally and enable
rest to more favorable location.
Rest Preparation
First altering
proximal tooth then
start rest
preparation
Large round bur used
to lower marginal
ridge and establish
outline form
Smaller round bur
used to deepen the
floor
Lingual Rest
Used for support an indirect retainer or auxiliary
rest.
● Canine preferred.
● Preferred over incisal rest due to proximity to
center of rotation which reduce tipping.
Maybe placed at cingulum or just incisal to it.
Preparation of lingual rest
● At junction of gingival
and middle 3rd.
● Apex incisally.
● Prepared by inverted
cone diamond with
progress to smaller
taper stones with round
ends
● Avoid enamel undercut.
● Floor seat toward
cingulum rather than
axial wall.
Slight rounded V
Lingual Rest
● Especially for mandibular
canine due to too steep
lingual inclination.
● Using Cr-Co rest seats
cemented by resin
cement.
On cast crown
Incisal rests
Must be placed at incisal angles and used as
auxiliary rest or indirect retainers.
● Least desirable.
● Applicable to mandibular canine.
● Preferrable to ¾ crown.
Preparation of Incisal rest
● Form rounded notch at
incisal angle.
● Deepest portion is apical
to incisal edge.
● Notch should be beveled
labially and lingually.
● 2.5mm wide.
● 1.5mm deep.
Direct Retainers
Components which resist movement away from
the teeth/tissue.
Greatly influenced by stability and support
provided by other components.
Basic Principles of Clasp Design
● Principle of encirclement: >180 degrees in greatest
circumference of the tooth.
● Engagement in two forms:
○ Continuous contact (circumferential clasp)
○ Discontinuous contact (bar clasp)
Basic Principles of Clasp Design
● Occlusal rest should prevent movement of clasp
arm toward cervical direction.
● Each retentive terminal should be opposed by
reciprocal terminal.
● Clasp retainers on abutment adjacent to distal
extension bases should act as stress breakers by
design or construction.
Basic Principles of Clasp Design
● Retentive clasps should be bilaterally opposed to
control path of removal and stabilize against
rotational movement.
● Path of escapement for each retentive clasp
terminal must be other than parallel to path of
removal.
Basic Principles of Clasp Design
● The amount of retention should be always minimum
necessary to resist reasonable dislodging forces.
● Reciprocal elements should be at junction of
gingival and middle 3rd of abutment, while the
terminal retentive arm placed in gingival 3rd of
crown.
Reciprocal Arm
● Resist movement in response to deformation of
the retainer arm as it engages a tooth height of
contour.
● Aid in stabilizing against horizontal movement.
● May act as indirect retainer only when it rests on
suprabulge surface of abutment anterior to fulcrum
line.
Types of Direct Retainers
Intracoronal Extracoronal
Uses mechanical
resistance to
displacement
through
components
placed to external
surface of
abutment
Maybe cast or
attached within
restored natural
contours of
abutment
Principal forms of extracoronal retainer
Clasp retainer Interlocking
Most common.
Retain through
flexible clasp arm
engaging external
sruface of abutment
in area cervical its
greatest convexity.
Attahcments
engages tooth
contour to resist
occlusal displacment
spring loaded device
Clips or Rings
Flexible clips or rings
engaging rigid
component that is
cast or attached to
external surface of
abutment.
Clasp Assembly
Reciprocating
Arm
For stabilization
against horizontal
movement
Retentive
Arm
Engages a tooth
undercut
Minor
connector
From which clasp
originate
Principal
Rest
Direct stress
along long axis of
tooth
Clasp Assembly
Types of Clasp Assemblies
Designs to
accommodate
functional movement
RPI
RPA
Bar Clasp: T, modified T, I, and Y
Designs without
movement
accommodation
Circumferential clasp
Ring Clasp
Embrasure Clasp
RPI and RPA
They address class I lever changing fulcrum point.
It belongs to mesial rest concept.
To avoid harmful tipping and torquing on abutment
either:
- Change fulcrum location (mesial rest concept)
- Use of flexible arm (wrought wire)
RPI
RPI consist of:
- MO rest with minor connector into ML
embrasure not contacting adjacent tooth.
- Distal guiding plane from marginal ridge to
junction of middle and gingival 3rd
- I bar in the gingival 3rd of buccal of abutment.
RPA and Bar clasp
Used instead in case:
- Exaggerated buccal or lingual tilts.
- Severe tissue undercut.
- Shallow buccal vestibule.
Bar clasp classified by shape:
- T
- Modified T
- I
- Y
Bar clasp
Indications:
- Small degree of undercut in cervical 3rd.
- Abutment teeth for tooth supported or
modification areas.
- Distal extension base.
- Esthetic considerations.
Alternatives:
- Mesial originating ring clasp
- Cast clasp
- Wrought wire clasp
- Reverse action clasp
Combination Clasp
Reducing the effect of class I lever in distal extension by
using flexible component in resistance arm.
- Wrought wire retentive arm
- Cast reciprocal arm originating gingivally from denture
base.
- When mesial undercut exist and I bar not indicated.
Indications:
- Maximum flexibility desired.
- Weak abutment and bar contraindicated.
- Desired retention not predictable (adjustability)
- Esthetic over cast clasp.
Combination Clasp
Advantages:
- flexibility.
- Adjustability.
- Esthetic.
- Coverage minimum tooth surface (line contact).
- Less likely to have fatigue failure.
Disadvantages:
- Extra-step.
- Distortion by careless handling.
- Less stabilization in suprabulge tooth.
- Distort with function.
Circumferential Clasp
First consideration in all cast clasp.
Disadvantages:
- More tooth surface covered.
- May increase the occlusal surface of the tooth.
- Its half round form prevents its adjustment.
Consist of buccal and lingual arms.
Common error is using both terminal retentive ends.
Ring Clasp
Nearly encircle all tooth.
When proximal undercut cannot be approached.
ML undercut on lower molar due to proximity of occlusal
rest and cannot be approached by bar due to lingual
inclination.
Should never be used as unsupported ring.
Should be supported with struct on non-retentive side or
auxiliary rest.
Maybe used in reverse on abutment anterior to tooth
supported edentulous area.
Embrasure Clasp
In unmodified CII and CIII where no edentulous opposite
side.
Should not eliminate the contact.
It is recommended to be protected with crowns, due to
high percentage of fracture.
Need double occlusal rests.
Two retentive clasp arms and two reciprocal arms,
bilaterally or diagonally opposed.
Other types of retainers
Lingual
retention with
internal rests
Near verticla walls of
internal rests
providing
reciprocation against
lingual retentive arm.
With tooth supported
only on anterior
abutment
Internal attachments
Advantages
over
extracoronal
Eliminate visible
retentive and
supportive
components
Better vertical
support
Disadvantages
Require prepared
abutments and
castings.
Require complicated
lab and clinical
procedure
Difficult to repair and
replace
Cost
Wear with
progressive loss of
frictional resistance
Indirect Retainers
Provide retention for distal extension base when
dislodge from its basal seat, providing leverage
advantage and consists of one or more rests,
supporting minor connectors and proximal plates
adjacent to edentulous areas.
Indirect Retainer
Most effective location is as far as possible from distal
extension base, at area perpendicular to fulcrum line.
Using mostly canine and mesio-occlusal of 1st premolar.
Factors influence effective IR
1. Establish seating of principal occlusal rest on primary
abutment teeth. Total displacement of rest will cause
no rotation about fulcrum line.
2. Distance from fulcrum line considering: length of distal
extension, location of fulcrum line, how far IR is placed
from fulcrum line.
3. Rigidity of connectors supporting IR.
4. Effectiveness of supporting tooth surface. Avoid
inclined teeth and weak teeth.
Forms of IR
Cingulum bars
and
linguplates
Canine
extensions
from
occlusal
rests
Occlusal rest
Canine rest
Rugae
Support
CREDITS: This presentation template was created
by Slidesgo, including icons by Flaticon,
infographics & images by Freepik
Thanks

More Related Content

Similar to Major Minor Rest Direct Indirect Retainers.pptx

MAJOR CONNECTORS P (1).pptx
MAJOR CONNECTORS P (1).pptxMAJOR CONNECTORS P (1).pptx
MAJOR CONNECTORS P (1).pptx
Shruti Jumde
 
Major connectors notes
Major connectors notesMajor connectors notes
Major connectors notes
Hoang Hieu
 

Similar to Major Minor Rest Direct Indirect Retainers.pptx (20)

Major connectors/prosthodontic courses
Major connectors/prosthodontic coursesMajor connectors/prosthodontic courses
Major connectors/prosthodontic courses
 
9.MAJOR CONNECTORS.pptx
9.MAJOR CONNECTORS.pptx9.MAJOR CONNECTORS.pptx
9.MAJOR CONNECTORS.pptx
 
Major connectors/ General orthodontics
Major connectors/ General orthodonticsMajor connectors/ General orthodontics
Major connectors/ General orthodontics
 
Major connectors
Major connectorsMajor connectors
Major connectors
 
Rpi and rpa concept
Rpi and rpa conceptRpi and rpa concept
Rpi and rpa concept
 
mejor connectors in removable partial dentures
mejor connectors in removable partial denturesmejor connectors in removable partial dentures
mejor connectors in removable partial dentures
 
MAJOR CONNECTORS P (1).pptx
MAJOR CONNECTORS P (1).pptxMAJOR CONNECTORS P (1).pptx
MAJOR CONNECTORS P (1).pptx
 
Major connectors notes
Major connectors notesMajor connectors notes
Major connectors notes
 
Minor connectors and rests
Minor connectors and rests Minor connectors and rests
Minor connectors and rests
 
Mandibular Major Connectors
Mandibular Major ConnectorsMandibular Major Connectors
Mandibular Major Connectors
 
Maxillary & Mandibular Major Connectors.pptx
Maxillary & Mandibular Major Connectors.pptxMaxillary & Mandibular Major Connectors.pptx
Maxillary & Mandibular Major Connectors.pptx
 
removable Partial denture
removable Partial dentureremovable Partial denture
removable Partial denture
 
PPT (FINAL)The principles of RPD design & its components (Year 3) .pptx
PPT (FINAL)The principles of RPD design & its components (Year 3) .pptxPPT (FINAL)The principles of RPD design & its components (Year 3) .pptx
PPT (FINAL)The principles of RPD design & its components (Year 3) .pptx
 
RPD DESIGN
RPD DESIGNRPD DESIGN
RPD DESIGN
 
Rests & Rest seats in removable partial Dentures
Rests & Rest seats in removable partial DenturesRests & Rest seats in removable partial Dentures
Rests & Rest seats in removable partial Dentures
 
Anterior Partial Veneer crown preparation
Anterior Partial Veneer crown preparationAnterior Partial Veneer crown preparation
Anterior Partial Veneer crown preparation
 
B- Retention of Removable Partial Dentures
B- Retention of Removable Partial DenturesB- Retention of Removable Partial Dentures
B- Retention of Removable Partial Dentures
 
Major connectors
Major connectorsMajor connectors
Major connectors
 
b- Retainers of RPDs
b- Retainers of RPDsb- Retainers of RPDs
b- Retainers of RPDs
 
24. major connectors
24. major connectors24. major connectors
24. major connectors
 

More from Ammar Al-Kazan

More from Ammar Al-Kazan (13)

principles of PD design.pptx
principles of PD design.pptxprinciples of PD design.pptx
principles of PD design.pptx
 
altered-cast.pptx
altered-cast.pptxaltered-cast.pptx
altered-cast.pptx
 
indirect inlay restoration.pptx
indirect inlay restoration.pptxindirect inlay restoration.pptx
indirect inlay restoration.pptx
 
coloration technique facial prosthesis
coloration technique facial prosthesiscoloration technique facial prosthesis
coloration technique facial prosthesis
 
Endosseous implants in maxillofacial prosthesis.pptx
Endosseous implants in maxillofacial prosthesis.pptxEndosseous implants in maxillofacial prosthesis.pptx
Endosseous implants in maxillofacial prosthesis.pptx
 
Prosthetic rehabilitation of patient with partial and total.pptx
Prosthetic rehabilitation of patient with partial and total.pptxProsthetic rehabilitation of patient with partial and total.pptx
Prosthetic rehabilitation of patient with partial and total.pptx
 
Assessment of edentulous patient.pptx
Assessment of edentulous patient.pptxAssessment of edentulous patient.pptx
Assessment of edentulous patient.pptx
 
Cardiovascular medicine in dentistry.pptx
Cardiovascular medicine in dentistry.pptxCardiovascular medicine in dentistry.pptx
Cardiovascular medicine in dentistry.pptx
 
Clinical management of the edentulous maxillectomy patient.pptx
Clinical management of the edentulous maxillectomy patient.pptxClinical management of the edentulous maxillectomy patient.pptx
Clinical management of the edentulous maxillectomy patient.pptx
 
Resin bonding FOR MAXILLOFACIAL PROSTHESES.pptx
Resin bonding FOR MAXILLOFACIAL PROSTHESES.pptxResin bonding FOR MAXILLOFACIAL PROSTHESES.pptx
Resin bonding FOR MAXILLOFACIAL PROSTHESES.pptx
 
psychology of maxillofacial patients
psychology of maxillofacial patientspsychology of maxillofacial patients
psychology of maxillofacial patients
 
widening of PDL
widening of PDLwidening of PDL
widening of PDL
 
structural durability of prosthsis.pptx
structural durability of prosthsis.pptxstructural durability of prosthsis.pptx
structural durability of prosthsis.pptx
 

Recently uploaded

Circulation through Special Regions -characteristics and regulation
Circulation through Special Regions -characteristics and regulationCirculation through Special Regions -characteristics and regulation
Circulation through Special Regions -characteristics and regulation
MedicoseAcademics
 
Cardiac Impulse: Rhythmical Excitation and Conduction in the Heart
Cardiac Impulse: Rhythmical Excitation and Conduction in the HeartCardiac Impulse: Rhythmical Excitation and Conduction in the Heart
Cardiac Impulse: Rhythmical Excitation and Conduction in the Heart
MedicoseAcademics
 

Recently uploaded (20)

TEST BANK For Huether and McCance's Understanding Pathophysiology, Canadian 2...
TEST BANK For Huether and McCance's Understanding Pathophysiology, Canadian 2...TEST BANK For Huether and McCance's Understanding Pathophysiology, Canadian 2...
TEST BANK For Huether and McCance's Understanding Pathophysiology, Canadian 2...
 
TEST BANK for The Nursing Assistant Acute, Subacute, and Long-Term Care, 6th ...
TEST BANK for The Nursing Assistant Acute, Subacute, and Long-Term Care, 6th ...TEST BANK for The Nursing Assistant Acute, Subacute, and Long-Term Care, 6th ...
TEST BANK for The Nursing Assistant Acute, Subacute, and Long-Term Care, 6th ...
 
Creating Accessible Public Health Communications
Creating Accessible Public Health CommunicationsCreating Accessible Public Health Communications
Creating Accessible Public Health Communications
 
Integrated Neuromuscular Inhibition Technique (INIT)
Integrated Neuromuscular Inhibition Technique (INIT)Integrated Neuromuscular Inhibition Technique (INIT)
Integrated Neuromuscular Inhibition Technique (INIT)
 
linearity concept of significance, standard deviation, chi square test, stude...
linearity concept of significance, standard deviation, chi square test, stude...linearity concept of significance, standard deviation, chi square test, stude...
linearity concept of significance, standard deviation, chi square test, stude...
 
Cas 28578-16-7 PMK ethyl glycidate ( new PMK powder) best suppler
Cas 28578-16-7 PMK ethyl glycidate ( new PMK powder) best supplerCas 28578-16-7 PMK ethyl glycidate ( new PMK powder) best suppler
Cas 28578-16-7 PMK ethyl glycidate ( new PMK powder) best suppler
 
5Cladba ADBB 5cladba buy 6cl adbb powder 5cl ADBB precursor materials
5Cladba ADBB 5cladba buy 6cl adbb powder 5cl ADBB precursor materials5Cladba ADBB 5cladba buy 6cl adbb powder 5cl ADBB precursor materials
5Cladba ADBB 5cladba buy 6cl adbb powder 5cl ADBB precursor materials
 
Gallbladder Double-Diverticular: A Case Report المرارة مزدوجة التج: تقرير حالة
Gallbladder Double-Diverticular: A Case Report  المرارة مزدوجة التج: تقرير حالةGallbladder Double-Diverticular: A Case Report  المرارة مزدوجة التج: تقرير حالة
Gallbladder Double-Diverticular: A Case Report المرارة مزدوجة التج: تقرير حالة
 
TEST BANK For Timby's Introductory Medical-Surgical Nursing, 13th Edition by ...
TEST BANK For Timby's Introductory Medical-Surgical Nursing, 13th Edition by ...TEST BANK For Timby's Introductory Medical-Surgical Nursing, 13th Edition by ...
TEST BANK For Timby's Introductory Medical-Surgical Nursing, 13th Edition by ...
 
Circulation through Special Regions -characteristics and regulation
Circulation through Special Regions -characteristics and regulationCirculation through Special Regions -characteristics and regulation
Circulation through Special Regions -characteristics and regulation
 
TEST BANK for Wilkins’ Clinical Assessment in Respiratory Care, 9th Edition b...
TEST BANK for Wilkins’ Clinical Assessment in Respiratory Care, 9th Edition b...TEST BANK for Wilkins’ Clinical Assessment in Respiratory Care, 9th Edition b...
TEST BANK for Wilkins’ Clinical Assessment in Respiratory Care, 9th Edition b...
 
Cardiovascular Physiology - Regulation of Cardiac Pumping
Cardiovascular Physiology - Regulation of Cardiac PumpingCardiovascular Physiology - Regulation of Cardiac Pumping
Cardiovascular Physiology - Regulation of Cardiac Pumping
 
Cardiac Impulse: Rhythmical Excitation and Conduction in the Heart
Cardiac Impulse: Rhythmical Excitation and Conduction in the HeartCardiac Impulse: Rhythmical Excitation and Conduction in the Heart
Cardiac Impulse: Rhythmical Excitation and Conduction in the Heart
 
Hepar Sulphuris Remedy, Homoeopathic Materia Medica, HMM, 1st BhMS
Hepar Sulphuris Remedy, Homoeopathic Materia Medica, HMM, 1st BhMSHepar Sulphuris Remedy, Homoeopathic Materia Medica, HMM, 1st BhMS
Hepar Sulphuris Remedy, Homoeopathic Materia Medica, HMM, 1st BhMS
 
5CL-ADB powder supplier 5cl adb 5cladba 5cl raw materials vendor on sale now
5CL-ADB powder supplier 5cl adb 5cladba 5cl raw materials vendor on sale now5CL-ADB powder supplier 5cl adb 5cladba 5cl raw materials vendor on sale now
5CL-ADB powder supplier 5cl adb 5cladba 5cl raw materials vendor on sale now
 
Video capsule endoscopy (VCE ) in children
Video capsule endoscopy (VCE ) in childrenVideo capsule endoscopy (VCE ) in children
Video capsule endoscopy (VCE ) in children
 
Presentació "Advancing Emergency Medicine Education through Virtual Reality"
Presentació "Advancing Emergency Medicine Education through Virtual Reality"Presentació "Advancing Emergency Medicine Education through Virtual Reality"
Presentació "Advancing Emergency Medicine Education through Virtual Reality"
 
A thorough review of supernormal conduction.pptx
A thorough review of supernormal conduction.pptxA thorough review of supernormal conduction.pptx
A thorough review of supernormal conduction.pptx
 
Multiple sclerosis diet.230524.ppt3.pptx
Multiple sclerosis diet.230524.ppt3.pptxMultiple sclerosis diet.230524.ppt3.pptx
Multiple sclerosis diet.230524.ppt3.pptx
 
TEST BANK For Lewis's Medical Surgical Nursing in Canada, 4th Edition by Jane...
TEST BANK For Lewis's Medical Surgical Nursing in Canada, 4th Edition by Jane...TEST BANK For Lewis's Medical Surgical Nursing in Canada, 4th Edition by Jane...
TEST BANK For Lewis's Medical Surgical Nursing in Canada, 4th Edition by Jane...
 

Major Minor Rest Direct Indirect Retainers.pptx

  • 1. Major and Minor Connectors, Rest and Rest Seats, and Direct and Indirect Retainers Ammar G. Salem KHBMS 4th Year
  • 2.
  • 3. Major Connectors They unit the major parts of the RPD framework prosthesis It provides cross-arch stability to help resist displacement by functional stresses
  • 4. Should not substantially alter the natural contour of lingual surface or palatal vault It should be uniform for better stress distribution Guidelines Regarding Major Connector Rigidity Relief Uniformity Contour Flexible Major connector is ineffective and detrimental Avoid impinge on gingival tissue, bony or soft tissue prominence 01 02 04 05 Should not contribute to food trapping Design Cleansing Reuqire proper shape, thickness and location 03 06
  • 5. Mandibular Major Connectors Lingual Bar Linguoplate Sublingual Bar Lingual Bar with Cingulum Bar Cingulum Bar Labial Bar
  • 6.
  • 7. Lingual Bar Most common used. ● Cross-section is half pear shaped. ● Tapered superiorly and bulk inferiorly. ● Recommended placement as inferior as possible. It is recommended that superior border is minimum 4mm below gingival margin.
  • 8. Linguoplate Need terminal rest at each end. It should be contoured to follow nature of teeth and embrasures. Overlapped teeth need lingual proximal surfaces recontouring. ● High frenum attachment, slightly elevated floor. ● Class I with excessive vertical resorption. ● Stabilization of periodontally weakened teeth. ● When future replacement is expected.
  • 9. Design of Mandibular Major Connectors Step 4 Connect basal seat area to inferior and superior borders of major connector and add minor connectors to retain acrylic resin denture base. Step 2 Outline the inferior border of major connector Outline the superior border of major connector Step 3 Step 1 Outline basal seat areas
  • 10.
  • 11. Cingulum Bar and cingulum with lingual bar when Linguoplate indicated but lack axial alignment of anterior teeth, in case of excessive block-out of interproximal undercuts must be made. ● Located slightly above or on cingula. Acceptable esthetic in wide diastema than Linguoplate.
  • 12. Labial Bar In case of extreme lingual inclination of remaining lower premolar and incisor teeth. ● Can be avoided by recontouring or reshaping by means of crowns. Also when lingual tori is inoperable.
  • 13. Swing Lock Design Consist of labial bar connected to major connector by a hinge at one end and a latch at the other end and supported by multiple rests and stabilized by Linguoplate and retention by struts. ● Contraindicated in: poor oral hygiene, lack of plaque control, shallow labial vestibule, high frenum. ● Indicated in missing key abutments (canine), unfavorable tooth and soft tissue contours, teeth with questionable prognosis.
  • 14. Maxillary Major Connectors Single palatal strap Combination anterior and posterior palatal strap Palatal plate U shaped plate Signle palatal bar Anterior posterior palatal bar
  • 15. Single palatal strap In bilateral tooth supported particularly when short spaces are posteriorly positioned. In Class II with cross-arch attachment by extracoronal retainers or internal attachments.
  • 16. Anterior-Posterior palatal Strap Almost any design of Class II and Class IV ● Anterior component better to avoid rugae coverage, posterior to crest or in the valley. ● Posterior component should be flat, minimum width 8mm, avoiding tongue interference and anterior to vibrating line. ● Should form square, rectangular form.
  • 17. Palatal Plate Require anatomic replica and uniform thickness. ● Used in Class I when last abutment is canine or 1st premolar with excessive vertical ridge resorption. ● Two or more edentulous areas. In form of complete plate or partial plate.
  • 19. Design of Maxillary Major Connectors Step 1 Step 2 Outline primary stress bearing areas Outline non-bearing areas Step 3 Outline connector areas Step 4 Step 5 Selection of connector type Unification
  • 20.
  • 21. U-shaped Palatal Connector Least desirable. ● In case of large inoperable torus and replacement of multiple anterior teeth. It lacks rigidity, fail to support well, and bulkiness hinder the tongue. Should be supported by rests and being away from gingival tissue.
  • 22. Single Palatal Bar Highly objectionable. Need bulk and being centered.
  • 23. Minor Connectors They connect the major connector to other components of framework. (prosthesis to abutment function): transfer functional stress to abutment teeth and underlying tissue. (abutment to prosthesis): transfer effect of components throughout prosthesis.
  • 24. Minor Connector: form and location Bulk Convex surface For rigidity When contacts axial surface of abutment In embrasure For tongue interference Pass vertical Tapering Should cross abrupt Toward contact area
  • 25. junctions should be strong butt joint without much bulk. Angle not more than 90 degrees. Open latticework/ladder type is preferred. On mandible extending 2/3rd length of residual ridge, while on maxilla extending entire length. On mandible should extend buccally and lingually to minimize distortion of resin during processing. Denture base minor connector
  • 26. • Integral part for retention of acrylic resin bases. • Provide stability for framework during transfer and processing. • Prevent distortion during resin processing. Tissue Stop minor connector
  • 27. • Medial extent depends on later extent of major connector. • Too far medial position alter the natural contour. • Too far buccal position make difficult to create natural contour of acrylic resin on lingual surface of artificial teeth. • Best line is 2mm medial to imaginary line contacting lingual surfaces of missing posterior teeth. Finishing Lines of minor connector
  • 28. Rest and Rest Seat Any component that provide vertical support on tooth surface for denture. Must be rigid Can be: Occlusal – Lingual - Incisal
  • 29.
  • 30. Occlusal Rest ● Conventional. ● Extended. ● Interproximal ● Internal
  • 31. Guidelines ● Outline rounded triangular with apex toward center of occlusal surface. ● The base at marginal ridge at least 2.5mm. ● Lower marginal ridge to permit bulk of metal (1.5mm) ● Floor seat should be apical to marginal ridge, concave spoon shaped. ● Angle between rest and vertical minor connector not less than 90 degrees.
  • 32. Extended occlusal rest Recommended in Class II modification 1 and Class III where most posterior abutment is mesially tipped molar. ● > half of mesiodistal width. ● 1/3rd of buccolingual width. ● Minimum 1mm thickness of metal. Purpose to minimize tipping and ensure forces to long axis of abutment.
  • 33. Interproximal occlusal rest Similar to occlusal rest seats with exception of lingual extension. ● Avoid reducing or eliminating contact points. ● Analyze possible interocclusal interference. ● Avoid creation of vertical groove.
  • 34. Internal occlusal rest Entirely supported by cast retainers. ● Provide support and stabilization. ● Form parallel to path of insertion, slightly tapered occlusally, and dovetailed. ● Only for tooth supported RPD. Eliminate visible clasp arm buccally and enable rest to more favorable location.
  • 35. Rest Preparation First altering proximal tooth then start rest preparation Large round bur used to lower marginal ridge and establish outline form Smaller round bur used to deepen the floor
  • 36. Lingual Rest Used for support an indirect retainer or auxiliary rest. ● Canine preferred. ● Preferred over incisal rest due to proximity to center of rotation which reduce tipping. Maybe placed at cingulum or just incisal to it.
  • 37. Preparation of lingual rest ● At junction of gingival and middle 3rd. ● Apex incisally. ● Prepared by inverted cone diamond with progress to smaller taper stones with round ends ● Avoid enamel undercut. ● Floor seat toward cingulum rather than axial wall. Slight rounded V
  • 38. Lingual Rest ● Especially for mandibular canine due to too steep lingual inclination. ● Using Cr-Co rest seats cemented by resin cement. On cast crown
  • 39. Incisal rests Must be placed at incisal angles and used as auxiliary rest or indirect retainers. ● Least desirable. ● Applicable to mandibular canine. ● Preferrable to ¾ crown.
  • 40. Preparation of Incisal rest ● Form rounded notch at incisal angle. ● Deepest portion is apical to incisal edge. ● Notch should be beveled labially and lingually. ● 2.5mm wide. ● 1.5mm deep.
  • 41. Direct Retainers Components which resist movement away from the teeth/tissue. Greatly influenced by stability and support provided by other components.
  • 42. Basic Principles of Clasp Design ● Principle of encirclement: >180 degrees in greatest circumference of the tooth. ● Engagement in two forms: ○ Continuous contact (circumferential clasp) ○ Discontinuous contact (bar clasp)
  • 43. Basic Principles of Clasp Design ● Occlusal rest should prevent movement of clasp arm toward cervical direction. ● Each retentive terminal should be opposed by reciprocal terminal. ● Clasp retainers on abutment adjacent to distal extension bases should act as stress breakers by design or construction.
  • 44. Basic Principles of Clasp Design ● Retentive clasps should be bilaterally opposed to control path of removal and stabilize against rotational movement. ● Path of escapement for each retentive clasp terminal must be other than parallel to path of removal.
  • 45. Basic Principles of Clasp Design ● The amount of retention should be always minimum necessary to resist reasonable dislodging forces. ● Reciprocal elements should be at junction of gingival and middle 3rd of abutment, while the terminal retentive arm placed in gingival 3rd of crown.
  • 46. Reciprocal Arm ● Resist movement in response to deformation of the retainer arm as it engages a tooth height of contour. ● Aid in stabilizing against horizontal movement. ● May act as indirect retainer only when it rests on suprabulge surface of abutment anterior to fulcrum line.
  • 47. Types of Direct Retainers Intracoronal Extracoronal Uses mechanical resistance to displacement through components placed to external surface of abutment Maybe cast or attached within restored natural contours of abutment
  • 48.
  • 49. Principal forms of extracoronal retainer Clasp retainer Interlocking Most common. Retain through flexible clasp arm engaging external sruface of abutment in area cervical its greatest convexity. Attahcments engages tooth contour to resist occlusal displacment spring loaded device Clips or Rings Flexible clips or rings engaging rigid component that is cast or attached to external surface of abutment.
  • 50. Clasp Assembly Reciprocating Arm For stabilization against horizontal movement Retentive Arm Engages a tooth undercut Minor connector From which clasp originate Principal Rest Direct stress along long axis of tooth
  • 52. Types of Clasp Assemblies Designs to accommodate functional movement RPI RPA Bar Clasp: T, modified T, I, and Y Designs without movement accommodation Circumferential clasp Ring Clasp Embrasure Clasp
  • 53. RPI and RPA They address class I lever changing fulcrum point. It belongs to mesial rest concept. To avoid harmful tipping and torquing on abutment either: - Change fulcrum location (mesial rest concept) - Use of flexible arm (wrought wire)
  • 54. RPI RPI consist of: - MO rest with minor connector into ML embrasure not contacting adjacent tooth. - Distal guiding plane from marginal ridge to junction of middle and gingival 3rd - I bar in the gingival 3rd of buccal of abutment.
  • 55. RPA and Bar clasp Used instead in case: - Exaggerated buccal or lingual tilts. - Severe tissue undercut. - Shallow buccal vestibule. Bar clasp classified by shape: - T - Modified T - I - Y
  • 56. Bar clasp Indications: - Small degree of undercut in cervical 3rd. - Abutment teeth for tooth supported or modification areas. - Distal extension base. - Esthetic considerations. Alternatives: - Mesial originating ring clasp - Cast clasp - Wrought wire clasp - Reverse action clasp
  • 57.
  • 58. Combination Clasp Reducing the effect of class I lever in distal extension by using flexible component in resistance arm. - Wrought wire retentive arm - Cast reciprocal arm originating gingivally from denture base. - When mesial undercut exist and I bar not indicated. Indications: - Maximum flexibility desired. - Weak abutment and bar contraindicated. - Desired retention not predictable (adjustability) - Esthetic over cast clasp.
  • 59. Combination Clasp Advantages: - flexibility. - Adjustability. - Esthetic. - Coverage minimum tooth surface (line contact). - Less likely to have fatigue failure. Disadvantages: - Extra-step. - Distortion by careless handling. - Less stabilization in suprabulge tooth. - Distort with function.
  • 60. Circumferential Clasp First consideration in all cast clasp. Disadvantages: - More tooth surface covered. - May increase the occlusal surface of the tooth. - Its half round form prevents its adjustment. Consist of buccal and lingual arms. Common error is using both terminal retentive ends.
  • 61. Ring Clasp Nearly encircle all tooth. When proximal undercut cannot be approached. ML undercut on lower molar due to proximity of occlusal rest and cannot be approached by bar due to lingual inclination. Should never be used as unsupported ring. Should be supported with struct on non-retentive side or auxiliary rest. Maybe used in reverse on abutment anterior to tooth supported edentulous area.
  • 62. Embrasure Clasp In unmodified CII and CIII where no edentulous opposite side. Should not eliminate the contact. It is recommended to be protected with crowns, due to high percentage of fracture. Need double occlusal rests. Two retentive clasp arms and two reciprocal arms, bilaterally or diagonally opposed.
  • 63. Other types of retainers Lingual retention with internal rests Near verticla walls of internal rests providing reciprocation against lingual retentive arm. With tooth supported only on anterior abutment
  • 64. Internal attachments Advantages over extracoronal Eliminate visible retentive and supportive components Better vertical support Disadvantages Require prepared abutments and castings. Require complicated lab and clinical procedure Difficult to repair and replace Cost Wear with progressive loss of frictional resistance
  • 65. Indirect Retainers Provide retention for distal extension base when dislodge from its basal seat, providing leverage advantage and consists of one or more rests, supporting minor connectors and proximal plates adjacent to edentulous areas.
  • 66. Indirect Retainer Most effective location is as far as possible from distal extension base, at area perpendicular to fulcrum line. Using mostly canine and mesio-occlusal of 1st premolar.
  • 67. Factors influence effective IR 1. Establish seating of principal occlusal rest on primary abutment teeth. Total displacement of rest will cause no rotation about fulcrum line. 2. Distance from fulcrum line considering: length of distal extension, location of fulcrum line, how far IR is placed from fulcrum line. 3. Rigidity of connectors supporting IR. 4. Effectiveness of supporting tooth surface. Avoid inclined teeth and weak teeth.
  • 68. Forms of IR Cingulum bars and linguplates Canine extensions from occlusal rests Occlusal rest Canine rest Rugae Support
  • 69.
  • 70. CREDITS: This presentation template was created by Slidesgo, including icons by Flaticon, infographics & images by Freepik Thanks

Editor's Notes

  1. Anatomic replica advantages: Making thin uniform plate more acceptable to tongue. Corrugation add strength. Intimate contact provide greater retention.
  2. Anatomic replica advantages: Making thin uniform plate more acceptable to tongue. Corrugation add strength. Intimate contact provide greater retention.
  3. Non bearing areas: Lingual gingival tissue within 5-6mm of remaining teeth. Hard area of medial palatal raphe. Tori. Palatal tissue posterior to vibrating line. Factors affecting choice of connector type: Mouth comfort Rigidity Location of denture bases Indirect retention.
  4. Deepest part of embrasure should be block-out to avoid wedging effect.
  5. Primary purpose of vertical support: Maintain components in their planned position. Maintain established occlusal relationships by preventing settling of denture. Prevents impingement of soft tissue. Directs and distributes occlusal loads to abutment teeth
  6. If occlusal rest inclined apically toward reduced marginal ridge and cannot be modified, then a secondary rest must be employed on the side of tooth opposite to primary rest.
  7. 2nd step outline form 3rd step desired spoon shape form
  8. MesioDistal length 2.5-3mm LabioLingual Width 2mm Incisal Apical Depth 1.5mm
  9. On multiple incisors of mandible in case: Advantage of natural incisal faceting. Tooth morphology doesn’t permit other designs. Restore defective abraded tooth. Stabilization. Restore anterior guidance.
  10. Two means of retention: Mechanical retention on abutment. Intimate relation of minor connector contacts with guiding planes and denture bases and major connector with underlying tissue.
  11. Tooth contact at least 3 areas: Occlusal rest. Retentive clasp terminal. Reciprocal clasp terminal. One approaches from occlusal and the other approaches from cervical direct.
  12. Unless guiding planes used. To provide engagement with resistance to deformation.
  13. .
  14. Must contact tooth during time of retainer arm deformation.
  15. Prefabricated key and keyway. Regarded as internal or precision attachment.
  16. Prefabricated key and keyway. Regarded as internal or precision attachment.
  17. I bar should be tapered to its terminus. No more than 2mm of tip contacting abutment. Horizontal approach at least 4mm from gingival margin.
  18. Form of bar is not significant Usually used in tooth supported (bar clasp)
  19. Not flexible due to its half round form and several planes of design. Advantages of Infrabulge clasp: Esthetic Increased retention without tipping. Less chance of accidental distortion.
  20. Contraindications for I bar
  21. Line contact
  22. Other types Multiple clasp Half and half clasp Reverse action clasp
  23. - Eliminate visible clasp, circumferential, should be wrought wire, arise from rest
  24. - Similar horizontal stabilization of internal rest. - Should not be used with extensive tissue supported extension (all forces transmit to abutment) unless stress breaker used. - Using locking type (Intracoronal or extracoronal)
  25. Other functions: Reduce anteroposterior tilting leverage on principal abutment, especially isolated one. Aid in stabilization through contact of its minor connector, and auxiliary guiding plane. Stabilization of anterior teeth against lingual movement. Facilitate stress distribution by acting as auxiliary rest. Provide best visual indication for need to reline an extension base.
  26. Occlusal rest: CI arch on mesial marginal ridge of 1st premolar. Canine rest: when 1st premolar is too close to fulcrum line, or teeth overlapped. Finger extension from premolar rest, when 1st premolar is primary abutment. - If secondary abutment is located far from fulcrum line, it may serve as IR, example is DO rest on 1st premolar when 2nd premolar and 1st molar are missing and primary abutment is 2nd molar. In horseshoe design.