Sainavle

Question 1. Removable Partial Dentures Internal attachments.
Answer:

Definition Of Removable Partial Dentures Internal Attachments:

“A retainer, used in removable partial denture construction, consisting of a metal receptacle and a closely fitting part:

• The former is usually contained with the normal or expanded contours of
• The crown of the abutment tooth and the latter is attached to a pontic or the denture framework”.

Types of Removable Partial Dentures Internal attachments:

Read And Learn More: Prosthodontics Question And Answers

• Ney-Chayes attachment
• Stern Goldsmith attachment
• Baker attachment

Removable Partial Dentures Notes

Advantages Of Removable Partial Dentures Internal attachments:

• It eliminates the visible retentive component
• It eliminates the visible vertical support
• It provides horizontal stabilization
• It stimulates the underlying tissues

Disadvantages Of Removable Partial Dentures Internal Attachments:

• It requires the preparation of abutments
• It requires tedious lab procedures
• It leads to tooth wear
• It is least effective in teeth with small crowns It is difficult to place

Contraindications Of Internal Attachments::

• Teeth with large pulp
• Cost efficient

RPD Prosthodontics Guide

Question 2. Canine rests.
Answer:

Canine Rests is a form of indirect retainer

1. Canine Rests Indication: If the mesial marginal ridge of the first premolar is close to the fulcrum line
2. Canine Rests Modification: The minor connector can be placed anterior to the canine
3. Canine Rests Advantage: It increases the efficacy of the indirect retainer

Question 3. Purposes of a surveyor.
Answer:

• To survey the diagnostic and primary casts
• For tripoding the cast
• To transfer the tripod marks to another cast
• To contour crowns and cast restorations
• To perform mouth preparation directly on the cast to determine the outcome of treatment
• To survey the master cast
• To survey ceramic veneers before final glazing

Question 4. Gingivally approaching clasps
Answer:

Gingivally Approaching Clasps is infrabulge clasp

Gingivally Approaching Clasps Advantages:

• Easy to seat
• Esthetic
• Does not increases the occlusal load
• No decalcification of teeth

Gingivally Approaching Clasps Disadvantages:

• Gingivally Approaching Clasps tends to collect food debris
• Gingivally Approaching Clasps needs additional stabilizing units

Question 5. Survey Lines

Survey Line: “A line drawn on a tooth or teeth of a cast by means of a surveyor for the purpose of determining the positions of the various parts of a clasp or clasps”.

1. High Survey Line:
   • This line passes from the occlusal third in the near zone and to the occlusal third in the far zone
   • If the survey line lies higher in position, the undercut will be deep
     In this wrought wire clasp with more flexibility is used It is usually common in inclined teeth and in teeth with greater occlusal diameter than its cementoenamel junction
2. Medium Survey Line:
   • It passes from the occlusal third in the near zone to the middle third in the far zone
   • In it Aker’s clasp is used
3. Low Survey Line:
   • This survey line is closer to the cervical third of the tooth in both the near and far zone
   • A modified T clasp is used for teeth with low survey line

Removable Partial Denture Components

CLASP Used: A modified T – Clasp is used

Question 6. U-shaped major connector.
Answer:

• U-shaped Major Connector has a thin metal band running along lingual surface of posterior teeth
• Anteriorly it covers cingula of the teeth

U-shaped Major Connector Indications:

• Used in Kennedy’s class 4
• Used in the presence of tori
• Used in excessive over-bite

U-shaped Major Connector Advantages:

• Reasonably strong
• Has moderate indirect retention and support

U-shaped Major Connector Disadvantages:

• When vertical forces are applied on either one or both ends it tends to straighten
• Greater bulk is required to avoid flexing of the major , connector
• Increased thickness may cause patient discomfort

Question 7. Indications for removable partial dentures (RPD).
Answer:

• Length Of Edentulous Span – RPD are preferred for longer edentulous arches as it helps to distribute forces around the ridge evenly
• Age – RPD are preferred in young patients due to presence of large dental pulps
• Abutment – When there is no tooth posterior to the edentulous space to act as abutment, RPD is preferred
• Periodontal Support – Tooth with weakened periodontal support are preferred for RPD as it requires less support from the abutment

• Cross- Arch Stabilization –  To stabilize the remaining teeth against lateral and anteroposterior forces, RPD is indicated

• Excessive Bone Loss –  In case of ridge resorption, RPD can be fabricated as it can provide the required support and esthetics
• Immediate Teeth Replacement – RPD is preferred as relining can be done
• Esthetic Requirement – If required
• Emotional Problems –  RPD is indicated as it requires shorter appointments
• Patient Desires –
  • If the patient wants RPD due to
  • Avoidance of operative procedure
  • Economic reasons
  • Severe loss of tissue
  • Teeth with short clinical crown
  • When more than two posterior teeth or four anterior teeth are missing
  • If the canine and two of its adjacent teeth are missing
  • When there is no distal abutment
  • Presence of multiple edentulous spaces
  • In case of tilted abutment

Removable Partial Denture Designs

Question 8. Factors determining path of insertion.
Answer:

• Aesthetics: The cast should be tilted so that the height of contour is shifted to a lower level This conceal the clasp arm as well as alters the path of insertion
• Guiding Planes: Two or more vertically parallel surfaces of abutment teeth so oriented as to direct the path of placement and removal of removable partial denture”
  • The path of insertion will always be parallel to the guide plane
  • The proximal plates on the partial denture will contact the guide planes during insertion

• Location of the vertical minor connector
• This minor connector will be parallel to the guide plane on the abutment which in turn determines the path of insertion

• Interference:
  • Certain areas can cause interference to the insertion
  • If these cannot be surgically removed, the path of insertion should be altered
  • Interference Examples:
    1. In Mandible:
       • Lingual tori
       • Lingually placed teeth
       • Bony exostoses
    2. In Maxilla:
       • Tori palatinus
       • Buccaly tipped teeth
       • Bony exostoses
•  Retentive Undercuts:
  • Favourable undercuts should be evaluated to ob- tain good retention
  • The cast can be tilted until the height of contour lies between the gingival and middle third of the crown to obtain a good undercut
  • This tilting of the cast will alter the path of insertion

RPD Procedure Explained

•  Point Of Origin Of The Approach Arm Of A Bar Clasp:
  • The Approach arm forms a loop that produces terference during insertion
  • If the approach arm cannot be modified the path of insertion is to be altered
  • When the path of insertuion is altered the resulting bar clasp will not provide retention rather it will provide resistance to removal

• Denture Base:
  • Shape and extent of it determines the path of insertion
  • If the denture base extends anteriorly on both sides, it embraces abutment limiting multiple paths of insertion

Question 9. Single Palatal Bar.
Answer:

Single Palatal Bar is a bar running oval cross-section.

• Single Palatal Bar Design:
  • It has a narrow half across the palate
  • It is thickest at the centre
• Single Palatal Bar Fabrication:
  • Mark the extent of the bar on a cast
  • The wax pattern is fabricated and adapted over the area
• Single Palatal Bar Indication:
  • For interim partial dentures
• Single Palatal Bar Disadvantages:
  • Poor bony support
  • Cannot be used anterior to the premolar
  • It has poor vertical support
  • It can be used only in Kennedy’s Class 3 cases

Question 10. Factors determining clasp retention/flexibility.
Answer:

• Depth Of The Undercut: The deeper the undercut the greater is the retention
• Buccolingual Width Of The Undercut:
• Clasp alloys are selected based on it
  • For 0.010″ undercut-cast chrome alloy
  • For 0.015″ undercut – Gold alloy
  • For 0.020″ undercut – Wrought wire
• The Distance Between The Survey Line And The Tip Of The Retentive Clasp:

• The Mesiodistal Length Of The Clasp Arm Below The Height Of Contour:
  • Longer clasp arms offer more flexibility
  • Increased flexibility decreases the magnitude of the horizontal stresses acting on the abutment

• Taper Of The Clasp Arm:
  • The clasp arm should taper uniformly from its origin to the tip

• Cross-Sectional Form:
  • A half-round clasp arm is flexible only in one plane
  • While round clasp is flexible in all planes
  • A cast retentive clasp arm is used mainly in tooth-supported partial dentures because they need to flex only during placement and removal of the denture

Question 11. Occlusal Rest Seat Preparation.
Answer:

The location and extent of the rest seat is determined during the surveying of a diagnostic cast

1. On Enamel:

• A depth orientation groove is drawn along the desired outline
• Next, the enamel is removed between these grooves using the same bur
• The design is then verified with that marked on the primary cast
• Occlusal clearance is checked with the help of a beading/utility
• Rounding of internal line angles is carried out
• Any unsupported enamel if remains is removed
• Finally, the polishing of the rest seat is carried out

2. Gold Restoration:

• Tooth reduction/preparation is carried out for gold restoration
• Depression is made on the tooth surface at the place of the rest seat
• Initially, the rest seat is prepared on a wax pattern using a No. 4 round bur in slow-speed handpiece or with a discoid or cleoid excavator
• It is polished using a finishing bur
• Finally, the wax pattern is cast

1. On Amalgam Restoration:
   • Rest seat preparation over amalgam restoration is usually avoided as it would weaken the restoration
2.  For Embrasure Clasp:
   1. Two occlusal reset seats are to be prepared over the involved teeth
   2. Both the marginal ridges are reduced equally, but the contact point should not be removed
   3. The outline must be verified
   4. Finally, finishing and polishing is done using No. 4 round steel bur

Question 12. Methods for obtaining functional support for distal extension base.
Answer:

Support for distal extension base is obtained by following methods

• Functional Impression Technique:
  • The tissues get compressed during function leading to the vertical displacement of the denture
  • This type of tissue ward movement of the denture will produce rotation of the prosthesis around its terminal abutment axis
  • This is prevented if the tissues are recorded in a compressed form
  • The denture fabricated from it will seat and compress the tissues even during rest and there will be no additional tissue ward movement during function

• Providing Minimal Occlusal Contact
  • The occlusal load can affect the support of the denture
  • The occlusal table of the artificial teeth should be narrowed to reduce the occlusal load
• Identification Of Stress-Bearing Area
  • The distal extension base derives support from the stress-bearing area
  • These areas are identified in the maxillary and mandibular arch
  • Maxillary:
    • Buccal slopes of the ridge
    • Hard palate Crest of the ridge
  • Mandibular:
    • Buccal shelf area
    • Slopes of the ridge
• Minimizing The Movement Of The Denture Base:
  • The denture base should be designed such that the forces acting on the edentulous ridge can be minimized
  • Minor connectors are added to avoid the rotation of the denture
•  Increasing The Tissue Coverage Of The Denture Base:
  • Increasing the tissue coverage leads to a wider distribution of the occlusal load
  • Thus, it provides support

Question 13. Distal extension denture base.
Answer:

Distal extension denture bases are fabricated in case of Kennedy’s class 1 and class 2 cases

• Support for such bases is necessary as the occlusal load may rotate the denture
• Support for a distal extension denture is obtained from both the teeth and the tissues
• Among it the teeth are less compressible and intrude little to the occlusal load compared to the supporting soft tissues.

Factors Affecting Distal Extension Denture Base

• Quality of soft tissues
• Quality of underlying bone Tissue coverage of denture base
• Amount of forces acting on denture Stress bearing area
• Fit of the denture
• Type of Impression

Question 14. Methods of establishing occlusal relationship in the removable partial denture.
(or)
Occlusal relation in removable partial denture.
Answer:

1. Noncontact Relation:
   1. Protrusion
   2. Lateral movement
   3. Rest position and freeway space
2. Contact Relation:
   1. Protrusive
   2. Retrusion
   3. Lateral
   4. Canine guided
   5. Group function
   6. Intercuspal

Removable Partial Denture Methods:

• Direct Apposition Of Cast:
  • Cast are fabricated
  • These casts are articulated
  • Occlusal is established over the cast on the articulator itself
• Interocclusal Record On Remaining Posterior:
  • The upper and lower trial dentures are inserted into patient’s mouth
  • Wax or impression paste is loaded onto the occlusal surface of teeth in the mandibular occlusal rim
  • The patient is asked to slowly retrude the mandible and close on the wax till tooth contact occurs
  • The trial dentures are removed and the wax is allowed to cool
  • Both the maxillary and mandibular trial dentures are placed on their articulated casts.
•  Occlusal Relation With Record Base And Rims:
  • Rims made from wax or modeling plastic are fabricated over record base
  • These are inserted into the patient’s mouth and various mandibular movements are recorded
•  Entirely With Rims:
  • The occlusal relation is recorded with the help of extraoral tracing
  • The record bases attached to the recording devices are inserted in the patient’s mouth
  • The pointer is coated with precipitated chalk and denatured alcohol
  • The patient is asked to perform protrusive, lateral, and anteroposterior movements

•  Registration Of Occlusal Pathways:
  • The record base is fabricated using metal/resin
  • A layer of sticky wax is placed over it
  • Next, the occlusal rim by hard inlay wax is fabricated It is inserted into the patient’s mouth
  • Mandibular movements are recorded

Question 15. Direct v/s Indirect Retention.
Answer:

Direct Retention:

• Retention obtained in a removable partial denture by the use of clasps or attachments that resist removal from the abutment teeth.
• Component of a removable partial denture used to re- tain and prevent dislodgement consisting of a clasp assembly called direct retainer

1. Retentive terminal
2. Retentive clasp arm
3. Reciprocal arm
4. Occlusal rest
5. shoulder
6. Body
7. Minor Connector

Direct Retention is the ability of the component to prevent the distion and provide indirect retention placement of the denture

Indirect Retention:

• It is the effect achieved by one or more indirect retainers of removable partial denture that reduce the tendency for a denture base to move in an occlusal direction or rotate about the fulcrum line.
• The component of a removable partial denture that assists the direct retainer in preventing displacement of the distal extension denture base by functioning through lever action on the opposite side of the ful- crum line called indirect retainer

Indirect Retention is the ability of the component to retain dentures in place

Question 16. Immediate partial denture.
Answer:

“A complete removable partial denture constructed for insertion immediately following the removal of natural teeth”

Types Of Immediate Partial Denture:

1. Temporary Immediate Partial denture
   • Indicated when the permanent immediate partial denture is likely to become ill-fitting due to more than normal bone resorption
2. Permanent Immediate Partial denture
   • Indicated when bone resorption is expected to be less and denture prognosis is good

Advantages Of Immediate Partial Denture:

• Immediate Partial Denture is more esthetics
• Prevents supra-eruption and drifting of the opposing and adjacent teeth
• Immediate Partial Denture acts like a splint over the surgical site thus controlling hemorrhage and swelling

Question 17. Swing Lock.
Answer:

• Described by Dr. Joe J.Simmons
• The swing lock has a labial bar in addition to lingual major connector
• The labial bar extends labially all along the arch
• The swing lock is attached to the remaining parts of the denture by a hinge on one side and a lock on the other

Swing Lock Method Of Use:

• The swing lock is unlocked during insertion and locked after insertion
• As the labial bar moves around a hinge joint these dentures are called “Swing lock dentures”

Swing Lock Function:

• To support periodontally weak teeth

Swing Lock Indications:

• If the functional abutment teeth are missing
• In case of abutment teeth that has questionable prognosis
• Presence of few remaining teeth
• Presence of unfavorable tooth contours
• When the position of the remaining teeth does not facilitates conventional design
• Presence of unfavorable soft tissue contours
• For retention and stability of a maxillofacial prosthesis.

Swing Lock Contraindications:

• Poor oral hygiene
• Shallow vestibule
• High frenal attachment

Swing Lock Advantages:

• Inexpensive
• Provide stability and retention
• It is possible to add additional teeth to it

Swing Lock Disadvantages:

• Poor esthetics
• Leads to lingual tipping of the teeth

Swing Lock Fabrication:

Metal selection chrome alloy
↓
Surveying of cast
↓
Designing of various components
↓
Making the impression
↓
Fabrication of framework
↓
Trying of the framework
↓
Jaw relation and teeth arrangement
↓
Insertion of the prosthesis

Removable Partial Dentures

Question 1. Contraindications for removable partial dentures
Answer:

• Patients with macroglossia tending to push the denture away
• Cannot be used in mentally retarded patients
• This should be avoided in patients with poor oral hygiene

Read And Learn More: Prosthodontics Question And Answers

Question 2. Linguoplate major connector
Answer:

• The superior border extends up to the cingulum
• Linguoplate is scalloped in between the teeth
• In the presence of large embrasures, it is made to dip down step back design
• Anteriorly, it should be supported by the rest

Linguoplate Major Connector Advantages:

• Rigid, stable
• Provide indirect retention

Linguoplate Major Connector Disadvantages:

• Food accumulation
• Decalcification of teeth
• Soft tissue irritation

Removable Partial Dentures Notes

Question 3. Ring clasp.
Answer:

Ring Clasp is example of a cast circumferential clasp

• Ring Clasp Indication:
  • Distal extension denture
• Ring Clasp Contraindication:
  • Soft tissue undercut
  • Buccinator’s attachment, if present close to the  lower molar
• Ring Clasp Disadvantages:
  • Alter food flow
  • Increased tooth surface coverage
  • Cannot retain its physical qualities
  • Difficult to repair or adjust

Question 4. Objectives of surveying
Answer:

• To achieve good retention and bracing by designing the rigid and flexible components of a removable prosthesis
• Aids in marking the survey lines by determining the height of the contour of hard and soft tissue areas above the undercut
• Decides the path of insertion
• Helps in deciding the areas into which the prosthesis should not extend by determining the undesirable undercuts

Question 5. Cingulum rest
Answer:

• Also known as lingual rest
• Cingulum Rest is placed on the lingual surface of a tooth
• Cingulum Rest is specially placed over maxillary canine

Question 6. Enameloplasty/ Dimpling.
Answer:

• Enameloplasty is defined as the intentional alteration of the occlusal surface of the teeth to change their form
• Enameloplasty is done to produce a retentive undercut
• Enameloplasty is a gentle depression created on the enamel surface of the abutment teeth to provide a retentive undercut It is done when abutment teeth do not provide any surface undercut
• Enameloplasty can also be done to modify the existing undercut

Question 7. Limitations of Kennedy’s classification.
Answer:

• Did not explain the length of the edentulous span or the number of missing teeth only provide number of modification spaces.
• Not enough consideration about the condition of teeth and the remaining supporting structures.
• No distinction between modification spaces which occur in the anterior segment to those of the posterior segment

RPD Prosthodontics Guide

Question 8. Uses of surveyor.
Answer:

• Surveying the diagnostic and primary casts
• Tripoding the cast
• Transferring the tripod marks to another cast
• Contouring wax pattern
• Contouring crowns and cast restoration Placing internal attachments and rests
• Performing mouth preparation on casts
• Surveying master cast
• Surveying ceramic veneer

Question 9. Cingulum bar
Answer:

• The Cingulum Bar is located on or slightly above the cingula of the anterior teeth
• Indications:
• Large embrasures
• Large diastema cases

Question 10. Merits of occlusal approaching clasp.
Answer:

Occlusally Approaching Clasp is easy to fabricate and repair

• Occlusally Approaching Clasp leads to less food retention
• Occlusally Approaching Clasp can be best applied in a tooth-supported partial denture
• Provides excellent support and retention

Question 11. Define  Interim Removable Denture.
Answer:

“A transitional denture may become an interim denture when all of the natural teeth have been removed from the dental arch”.

Question 12. Support for RPD
Answer:

• Support for RPD depends on
• Quality of the residual ridge
• Total occlusal load applied
• Accuracy of the denture base
• Accuracy and type of impression registration

Question 13. Height of Contour.
Answer:

Height of Contour Definition: A line encircling a tooth designating its greatest circumference at a selected position.

Height of Contour Significance:

• Height of the Contour is used as a guideline that helps in the placement of the components of the clasp
• The retentive clasp arm of the retentive arm is located above the height of contour while the retentive terminal lies below the height of the contour
• The reciprocal arm is located above the height of contour

Removable Partial Denture Components

Question 14. Guiding Planes.
Answer:

Guiding Planes Definition: “Two or more vertically parallel surfaces of abutment teeth so oriented as to direct the path of placement and removal of removable partial denture”.

Types Of Guiding Planes:

• Guide planes on abutment teeth supporting a tooth supported partial denture
• Guide planes on abutment teeth that supports a secondary distal extension denture base
• Guide planes prepared on lingual surfaces of abutment teeth
• Guide planes on anterior abutments

Functions Of Guiding Planes:

• Minimizes the wedging stresses on the abutments
• Makes insertion and removal easier
• Aids to stabilize the prosthesis against horizontal stresses
• Aids to stabilize individual teeth
• Guiding Planes improves oral hygiene
• Guiding Planes contributes to indirect retention and frictional retention

Question 15.  Internal Rests.
Answer:

• Internal Rests are large box shaped metallic extensions that function as intracoronary retainers
• Internal Rests differ from internal attachments
• Internal Rests are not pre-fabricated instead the rest seat is formed by the sound tooth structure

Question 16. Prothero’s cone theory.
Answer:

• Prothero described cone theory in 1916 to explain the basis for clasp retention
• He described the shape of the crown of premolars and molars to be equivalent to two cones sharing a common base
• The upper cone resembles the occlusal half of the tooth and the lower cone resembles the cervical half of the tooth
• A clasp tip that ends below the junction of the two cones will resist movement in the upward direction
• The degree of resistance to deformation determines the amount of clasp retention

Removable Partial Denture Designs

Question 17. Combination clasp.
Answer:

A Combination Clasp is a combination of wrought wire and rigid-cast alloy

1. Combination Clasp Indication: Maxillary canines and premolars
2. Combination Clasp Contraindications: Undercut adjacent to edentulous space
3. Combination Clasp Advantages: It has thin line contact It can flex in all planes
4. Combination Clasp Disadvantages:
   • Tedious lab procedures
   • Easily breaks or distorts
   • Poor stability

Question 18. Half and Half clasp.
Answer:

• Half And Half Clasp has a retentive arm arising from one direction and a reciprocal arm arising from another
• Thus it needs two minor connector
  1. First attaches the occlusal rest and the retentive arm to the major connector
  2. Second, connects the reciprocal arm with or without an auxiliary rest
• Half And Half Clasp Modification:  The reciprocal arm is converted into short bar to reduce the tooth coverage
• Half And Half Clasp Advantage: It provides dual retention

Question 19. Fulcrum Line.
Answer:

• Fulcrum Line Definition: “An imaginary line around which a partial denture tends to rotate”
• Fulcrum Line Location: It is usually formed at the terminal abutment axis

Types of Fulcrum line:

• Retentive Fulcrum Line: “An imaginary line connecting the retentive points of clasp arms, around which the denture tends to rotate when subjected to forces, such as the pull of sticky foods”.
• Stabilizing Fulcrum Line: “An imaginary line, connecting occlusal rests, around which the denture tends to rotate under masticatory forces”.

Question 20. Displacing forces.
Answer:

Question 21. Group Function.
Answer:

Group Function Definition:

Group Function is multiple contract relations between the maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact of several teeth acts as a group to distribute occlusal forces

Group Function Indications:

• End-on-end bite
• Anterior open bite
• Class 2 and Class 3 molar relation

Group Function Types:

RPD Procedure Explained

1. Group Function Partial group function:
   • In this occlusion, some of the posterior teeth are able to shear the load in excursion whereas others contact only in centric relation.
2.  Anterior group function:
   • A most practical method of dis occluding
3. Group Function Advantages:
   • Efficient and comfortable
   • Distributes wear over more teeth
   • Distributes stresses over more teeth
   • Distributes stresses to teeth farther from the condylar axis
4. Group Function Limitations:
   • Not possible in all cases
   • Some arch relations do not permit it
   • Concave anterior guidance permits it whereas

Question 1. Define rests and rest seats. Discuss the various types of rests, their functions, and their design considerations.
Answer:

1. Rest: It is defined as “A rigid extension of a fixed or removable partial denture which contacts a remaining tooth or teeth to dissipate vertical or horizontal forces.”

Removable Partial Dentures Long Essay

2.  Rest Seat: The prepared recess in a tooth or restoration created to receive the occlusal, incisal, cingulum or lingual rest

• Types Of Rest Seat:
  1. Based on the relation of rest to the direct retainer
     • Primary rest-placed along the clasp assembly
     • Secondary rest placed away from the clasp

Read And Learn More: Prosthodontics Question And Answers

1. 1. Based on the position of the rest
      • Occlusal rest placed on occlusal surface of posterior
      • Cingulum rest placed on lingual surface of the tooth
      • Incisal rest-placed on the incisal edge of the tooth

Question 2. Define indirect retainer. What are the functions of an indirect retainer?
Or
Write about various forms of indirect retainers in detail.
Or
Define indirect retainers and discuss in detail about various types of it.
Answer:

Indirect Retainers:

Indirect Retainers is defined as “a part of a removable partial denture which assists the direct retainers in preventing displacement of distal extension denture bases by functioning through lever action on the opposite side of the fulcrum line.

Functions Of Indirect Retainers:

• Indirect Retainers counteract the lifting forces and stabilizes the denture It counteracts horizontal forces and provide stability and support to the denture
• Indirect Retainers can splint and protect the anterior teeth
• Indirect Retainers may act as an auxillary rest
• The dislodgement of indirect retainer suggest the need of relining.

Types Of Indirect Retainers:

1. Auxillary Occlusal Rest:

• Auxillary Occlusal Rest is located on the occlusal surfaces away from the distal extension base
• Auxillary Occlusal Rest is placed perpendicular to the midpoint of the fulcrum line.
  • Location:
    • Bilaterally over 1st premolars in Kennedy’s class 1
    • Over 1st premolar of opposite side in Kennedy’s class 2

2. Canine Extension From The Occlusal Rest:

• Occlusal Rest is a finger-like extension from a premolar rest is placed on the lingual slope of the adjacent canine
• Occlusal Rest is used when the first premolar must also acts as a primary abutment

3. Canine Rest:

• If the mesial marginal ridge of the first premolar is close to the fulcrum line, canine rest is used.

4. Continuous Bar Retainers And Lingual Plates:

• In Kennedy’s class I and class II, these retainers are placed just above the middle third of the anterior teeth to act as indirect retainers.

5. Modification Areas:

• In class 2 modification I, the fulcrum line runs from the left second premolar to the right second molar
• In such cases, the direct retainer resting on right first premolar act as an indirect retainer

6. Rugae Support:

• As the rugae area is firm and well placed it can be used for indirect retention for a palatal horseshoe major connector.
• Horde shoe Connector lacks Posterior retention
• In this case ruge acts as indirect retainer

Removable Partial Denture Prosthodontics Notes

7. Direct Indirect Retention:

The reciprocal arm of a direct retainer located anterior to the fulcrum line may act as an indirect retainer.

8. Indirect Retention From Major Connector:

The major connector provides indirect rerention due to its rigidity

Question 3. Define direct retainers. Enumerate the requirements of direct retainers with a note on the circumferential clasp.
Answer:

Direct Retainers Definition:

Direct Retainers is defined as “A clasp or attachment placed on abutment tooth for the purpose of holding a removable denture in position

Direct Retainers Requirements:

1. Passivity:
   • The quality or condition of inactivity or rest assumed by the teeth, tissues, and denture when a removable partial denture is in place but not under masticatory pressure
   • The retentive function should act only when dislodging forces are present
2. Retention:
   • It is that quality inherent in the prosthesis that resists the force of gravity, the adhesiveness of foods, and the forces associated with the opening of the jaws
   • It is provided by the retentive arm of the clasp
3. Reciprocation:
   • It is defined as the means by which one part of a prosthesis is made to counter the effect created by another part
   • It is provided by a rigid reciprocal arm
   • It resists the stresses generated by the retentive arm
4. Encirclement:
   • It is the property of the clasp assembly to encompass more than 180 degrees of the abutment tooth either by continuous or broken contact to prevent dislodgement during the function
   • Each clasp much encircle more than 180 degree of the abutment tooth
   • There can be continuous contact or broken contact
5. Stability:
   • It is defined as the quality of a denture to be firm, steady, or constant to resist displacement by functional stresses and not to be subject to change of position when forces are applied
   • Provided by shoulder and vertical arm of minor connector
6. Support:
   • It is defined as holding up or serving as a foundation or prop for
   • It is resistance to the movement of the denture in a gingival direction provided by rest
   • Path of escapement should never coincide with the path of removal
   • Primary abutment should never exert tipping forces on the abutment
   • Place reciprocal elements at the height of the contour and retentive element below the height of contour

Circumferential Clasp/Maker’s Clasp

• These clasps embrace more than half of the abutment tooth
• Maker’s Clasp prevents the rotation of the denture
• They approach the undercut from an occlusal direction

Maker’s Clasp Advantages:

• Maker’s Clasp is easy to fabricate and repair
• Maker’s Clasp leads to less food retention
• Maker’s Clasp can be best applied in a tooth-supported partial denture
• Provides excellent support and retention

Maker’s Clasp Disadvantages:

• Maker’s Clasp covers a large tooth surface area
• Alters buccolingual width of the crown
• Interferes with the normal food flow
• This leads to food accumulation and decalcification of the tooth structure
• Deprives periodontal stimulation
• Maker’s Clasp cannot be used for cases with an undercut away from edentulous space

Question 4. Classify partial edentulous areas according to Applegate-Kennedy’s classification and mention Applegate’s rules for Kennedy’s classification.
Answer:

Applegate Kennedy’s classification:

• Proposed by Dr. Edward Kennedy in 1923
• Kennedy classified partially edentulous arches and not the dentures
• This classification is anatomical
• In Kennedy’s classification, he included 4 classes Further, 2 additional classes were included by Apple-gate

Applegate Kennedy’s Classification Is As Follows:

• Class 1:
  • Bilateral edentulous areas located posterior to the remaining natural teeth
  • There are two edentulous spaces located in the posterior region without any teeth posterior to it.
• Class 2:
  • The unilateral edentulous area located posterior to the remaining natural teeth
  • There is a single edentulous space located in the posterior region without any teeth posterior to it.
• Class 3:
  • Unilateral edentulous area with natural teeth anterior and posterior to it.
  • It indicates a single edentulous area that does not cross the midline of the arch
• Class 4:
  • The single, bilateral edentulous area located anterior to the remaining natural teeth
  • It crosses the midline of the arch
  • Teeth are present only posterior to the edentulous arch

• Class 5:
  • The edentulous area bounded anterior and posteriorly by natural teeth
  • But the anterior abutment is not suitable for support

• Class 6:
  • Edentulous area in which the teeth adjacent to the space are capable of total support of the required prosthesis

Applegate Kennedy’s Applegate’s Rules:

1. Rule One: Classification should follow rather than preceed extractions that might alter the original classification
2. Rule Two: If the third molar is missing and not to be replaced, it is not considered in the classification
3. Rule Three: If the third molar is present and is used as abutment, it is considered in the classification
4. Rule Four: If the second molar is missing and not to be replaced, it is not considered in the classification
5. Rule Five: The most posterior edentulous area or areas always determine the classification
6. Rule Six: Edentulous areas other than those, which determine the classification, are referred to as modification spaces and are designated by their number
7. Rule Seven: The extent of the modification is not considered, only the number of additional edentulous spaces are considered
8. Rule Eight: There can be no modification areas in class 4.

RPD Prosthodontics Long Questions

Question 5. Define surveyor. Mention its parts. Explain in detail step by step procedure in surveying and Functions.
Or
Define dental cast surveyor. Enumerate their function and Parts of surveyors.
Or
Describe the surveying procedure and Functions and Parts of surveyors.
Answer:

Definition Of Surveyor:

An instrument used in the construction of removable partial dentures to locate and delineate contours and relative positions of abutment teeth and associated structures

Parts Of Surveyor:

• Surveying Platform:
  • The surveyor is metal plate parallel to the floor
  • The surveyor forms base of the surveyor
  • A Cast holder is placed over it
• Cast Holder/Surveying Table:
  • Cast Holder has a base and table to place a cast
  • Cast Holder should not be tilted more than 10 degrees
•  Vertical Arm:
  • The Vertical Arm arises vertically from the surveying platform
• Horizontal Arm:
  • Vertical Arm extends from top of the vertical arm
  • Vertical Arm supports the surveying arm at its free end
  • Vertical Arm Variations:
    • Fixed- in Ney surveyor
    • Revolving- in Jelenko surveyor

• Surveying Arm:
  • Surveying Arm extends from free end of horizontal arm
  • Surveying Arm is parallel to the vertical arm
  • Surveying Arm can move upward and downward
  • Its lower end has mandrel for attachment of surveying tools
• SurveyingTools:
  • Analyzing Rod:
    • Analyzing Rod is solid cylindrical metal rod
    • Analyzing Rod helps to analyze the location of height of contours, presence and absence of undercut
    • Analyzing Rod helps to determine path of insertion

• • Carbon Markers:
    • Carbon Markers resemble the lead points
    • Carbon Markers are used to draw height of contour of the object
  • Undercut Gauges:
    • Undercut Gauges is used to measure the depth and location of the undercuts
    • Sizes:
      • According to Stewart-0.010″, 0.015″, 0.020″ According to McCracken- 0.010″, 0.020″, 0.030″
    • Shape:
      • Ney surveyor circular beaded
      • Jelenko- Fan shpaed bead

• • Wax Knife:
    • Used to trim the excess wax and to eliminate undesirable undercut

Surveying Procedure:

• The primary cast is mounted on the surveying table It is locked in the position with a zero-degree tilt with the help of clamps on the surveying table
• Surveying is mounted such that the occlusal surfaces of the remaining teeth are parallel to the base
• After this, the surveying arm is positioned in relation to the cast
• Surveying is positioned as follows:
  • First, the horizontal arm is adjusted vertically such that the surveying arm can contact at least three different spaced-out points on the cast
  • Surveying is locked to the vertical arm with the help of a thumb screw Next, the cast is analyzed by using different analyzing tools

Components of Removable Partial Dentures Essay

Analyzing Tools:

• Analyzing Rod:
  • Analyzing is the first surveying tool used
  • Analyzing is attached to the mandrel of the surveying arm
  • The cast is rotated against it to analyze the presence of undercuts whether favorable or unfavorable
•  Carbon Markers:
  • These resemble the lead points
  • After analyzing the teeth with analysing rod, it is replaced by carbon markers
  • These are used to draw survey lines, which denote the height of the contour of the teeth

• Undercut Gauges:
  • Undercut Gauges are used to measure the depth and location of the undercuts in three dimensions

Tripoding:

• Tripoding is done next to maintain the records of the primary cast in the master cast
• A carbon marker is fixed to the mandrel of the surveying arm along with a locked horizontal arm
• The surveying arm is moved freely
• Due to this three points are marked that lie in the same plane
• Additional reference points are marked
• They are
  • A distal marginal ridge of 1st premolar Incisal edge of the lateral incisor
  • Lingual cusp tip of 1st premolar of opposite side
• After marking the primary cast is removed and the master cast is placed on the surveying table
• The master cast is adjusted in the surveying table such that the carbon marker contacts in the same manner as that with the primary cast

Functions of Surveyor:

• Surveying the diagnostic and primary casts
• Tripoding the cast
• Transferring the tripod marks to another cast
• Contouring wax pattern
• Contouring crowns and cast restoration
• Placing internal attachments and rests
• Performing mouth preparation on casts
• Surveying master cast
• Surveying ceramic veneer

Uses Of Tripoding:

• Helps in positioning the master cast
• Helps to remount the diagnostic casts on the surveying table

Question 6. Define major connector. Mention different types and discuss criteria for the selection of major connectors.
Answer:

Definition of Major Connectors:

Major Connectors is defined as “A part of a removable partial denture which connects the components on one side of the arch to the components on the opposite side of the arch”

Types Of Major Connectors:

1. Maxillary:
   • Single posterior palatal bar
   • Palatal strap
   • Palatal plate
   • Antero posterior palatal bar
   • Horseshoe connector Closed horseshoe
   • Complete palate
2. Mandibular:
   • Lingual bar Lingual plate
   • Kennedy bar
   • Sublingual bar
   • Cingulum bar
   • Labial bar

Criteria For Selection Of Major Connectors:

Major connector should fulfill the following criteria

1.  Functional Requirement: It should distribute forces among all the teeth
2. Anatomical Restraints: In case of mandibular connector less space is present, hence connector is designed accordingly
3. Relief: Adequate amount of releif should be provided
4. Hygiene: It should be enable to clean the connector
5. Patient’s Compliance:
   • It should be accepted by the patient
   • It should be comfortable

Question 7. Define removable partial denture. How do you choose a direct retainer for RPD.
Answer:

Removable Partial Denture:

• Any prosthesis that replaces some teeth in a partially dentate arch is called a removable partial denture
• It can be removed from the mouth and replaced at will

Classification of RPDs in Prosthodontics

Selection Of Direct Retainer For RPD:

Type of direct retainer is selected according to the following condition

Question 8. What is the direct retainer? Describe its parts
Answer:

Definition of Direct Retainer:

Direct Retainer is defined as “A clasp or attachment placed on an abutment tooth for the purpose of holding a removable denture in position

Parts of Direct Retainer:

1. Retentive Arm:

“A flexible segment of a removable partial denture which engages an undercut on an abutment and which is designed to retain the denture”

Retentive Arm Parts:

1. Retentive Clasp Arm:
   • It is not flexible
   • It is located above the height of the contour
2. Retentive Terminal:
   • It is flexible
   • It is located below the height of the contour

2. Reciprocal Arm:

• “A clasp arm or other extension used on a removable partial denture to oppose the action of some other part or parts of the prosthesis”
• Reciprocal Arm is located on the opposite side of retentive arm
• Reciprocal Arm is placed above the height of the contour
  • Reciprocal Arm Functions:
    • Acts as an indirect retainer
    • Reciprocal Arm can resist the rocking of the denture base
    • Reciprocal Arm provides stability and reciprocation against the retentive arm
    • The denture is stabilized against horizontal movement

3. Retentive Arm Shoulder:

• The shoulder is part of the clasp that connects the body to the clasp terminals
• The shoulder lies above the height of the contour and provides stabilization against horizontal displacement

4. Retentive Arm Body:

• The Retentive Arm is part of the clasp that connects the rests and shoulders of the clasp to the minor connector.
• Retentive Arm is rigidly above the height of the contour
• Retentive Arm is designed such that it contacts the guide plane of the abutment during insertion and removal

5.Retentive Arm Rest:

• Retentive Arm is rigid extension of the removable partial denture that contacts a remaining tooth or teeth to dissipate vertical or horizontal forces
• Retentive Arm is the part of the clasp that lies on the occlusal or lingual or incisal edge or surfaces of the tooth
• Retentive Arm resists tissue-ward movement of the clasp by acting like a vertical stop

6. Minor connector:

• Minor Connector is connecting link between the major connector or base of a removable partial denture and other units of the prosthesis, such as clasps, indirect retainers and occlusal rests
• Minor Connectror joins the clasp with the remaining part of the metal framework

Question 9. Discuss how to achieve stress equalization in Kennedy’s class 1 and 2 situations.
Answer:

Stress Equalization Or Stress Breaker:

This is used for stress equalization in Kennedy’s class I and II situation

Definition of Stress Breaker:

A device that relieves the abutment teeth of all or part of the occlusal forces

Significance of Stress Breaker:

• In a tooth tissue-supported partial denture when an occlusal load is applied, the denture tends to rock due to the difference in the compressibility of the abutment teeth and the soft tissues
• This can produce harmful effects on the abutment teeth In order to protect the abutment from such conditions, stress breakers are incorporated into a denture

Advantages of Stress Breaker :

• Stress Breaker preserves the alveolar support of the abutment
• Stress Breaker helps to create balanced stress on the residual ridge and the abutment
• Stress Breaker requires minimal direct retention
• This avoids the frequent need for relining and rebasing Weak teeth are well splinted
• Stress Breaker produces a massaging effect over soft tissues

Disadvantages of Stress Breaker:

• Stress Breaker is expensive
• Stress Breaker is difficult to repair
• Stress Breaker gets easily distorted
• Stress Breaker tends to food accumulation
• Stress Breaker reduces the stability of the denture It reduces indirect retention

Types of Stress Breakers:

1. Stress Breakers Type 1:

• Here a movable joint is placed between the direct retainer and a denture base
• It decreases the amount of force acting on the abutment
• A Movable joint is placed between the direct retainer and denture base
• This joint may either be a Hinge or a ball and socket or a sleeve and cylinder
• Example: DALBO

2. Stress Breakers Type 2:

• Stress Breakers has flexible connections between the direct retainer and the denture base
• Stress Breakers can be a wrought wire connector divided or split major connector or a movable joint between two major connectors

Question 10. Classify direct retainers in the removable partial prosthesis. Explain about occlusal approaching clasps.
Answer:

Direct Retainer:

“A clasp or attachment applied to an abutment tooth for the purpose of holding a removable denture in position.”

Classification of Direct Retainer:

By Herman:

1. Extracorporeal Direct Retainer: “A part of a removable partial denture which acts as a direct retainer for the denture by partially encircling or contacting an abutment tooth”
   • Extracorporeal Direct Retainer includes:
     • Suprabulge clasps
     • Infrabulge clasps
2. Intracoronary Direct Retainer:
   1. In it, a part or the whole of the retentive components are located within the anatomic contour of the abutment teeth
      • Precision attachment
      • External attachment
      • Stud attachment
      • Bar attachment

Occlusally Approaching Clasps:

• Circumferential Clasp/Aker’s clasp:
  • These clasps embrace more than half of the abutment tooth
  • Clasps prevents the rotation of the denture
  • They approach the undercut from an occlusal direction
• Occlusally Approaching Clasps Advantages:
  • Clasps is easy to fabricate and repair
  • Clasps leads to less food retention
  • Clasps can be best applied in a tooth-supported partial denture
  • Provides excellent support and retention
• Occlusally Approaching Clasps Disadvantages:
  • Clasps covers a large tooth surface area
  • Alters buccolingual width of the crown
  • Interferes with the normal food flow
  • Leads to food accumulation and decalcification of the tooth structure
  • Deprives periodontal stimulation
  • It cannot be used for cases with an undercut away from edentulous space

Question 11. Give in detail the impression methods for providing adequate support in extension base removable partial denture.
Or
Physiologic impression in RPD
or
Functional relining methods
or
Fluid wax functional impression
or
Impression procedures for distal extension RPD
Answer:

• Dual impression techniques are used for extension base removable partial dentures.
• Such techniques record a part in the functional form and the remaining areas in the anatomical form

 Dual Impressions Are Classified As:

• Physiological Or Functional Dual Impression:
  • McLean’s technique
  • Hindle’s modification
  • Functional relining method
  • Fluid wax method
• Selective Pressure Technique:
  • McLean’s technique
  • A custom-made impression tray is fabricated over the edentulous areas of the primary cast
  • Occlusal rims are made on the custom tray
  • The tray is loaded with impression material
  • It is inserted into the patient’s mouth
  • Ask the patient to close on the rims
  • Due to this, the tissues under the tray are compressed and the impression is recorded in this relation
  • An alginate impression is made over the existing impression using a large stock tray
  • Finger pressure is applied on the stock tray
  • The impression is removed
  • This leads the alginate over the impression to carry the functional impression along with it
  • A cast is poured into the impression

• Hindle’s Modification:
  • A special tray with stoppers and occlusal rims is fabricated using primary cast
  • Hindle’s is loaded with impression material
  • Hindle’s is inserted in the patient’s mouth
  • A special stock tray with large holes loaded with alginate is used for over-impression
    • The finger is placed into the holes to apply pressure on the occlusal rim
    • Pressure is held till the alginate sets
    • This pressure pushes the tray against the edentulous ridge

• Functional Relining Method:
  • The single anatomic master impression is made
  • The master cast is made from it
  • It is then duplicated and a refractory cast is made • Soft metal spacer is adapted to the cast
  • A framework is fabricated using a refractory cast and tried in the patient’s mouth
  • Spacer is removed
  • A functional impression is made on the tissue surface of a framework using low-fusing modeling plastic
  • It is tempered and placed in the mouth
  • Sufficient pressure is applied
  • The modeling plastic at the borders of the framework is re-softened
  • Border molding is carried out
  • Modelling plastic is reduced by 1 mm
  • The final impression is made with zinc oxide eugenol impression paste.

• Fluid Wax Functional Impression:
  • The metal framework is fabricated using a refractory cast
  • Fluid Wax is tried in the patient’s mouth
  • The framework is positioned on the master cast
  • The outline of the tray is drawn on the master cast
  • The cast is coated with separating media
  • A spacer is adapted over the crest of the edentulous ridge
  • The framework is placed over the spacer
  • Auto-polymerizing resin is adapted over the framework
• Excess Material Is Trimmed:
  • Relief holes are made along the crest of the ridge
  • Impression wax is softened and painted over the tissue surface of the framework
  • It is seated in the patient’s mouth with half-open for at least 5 minutes
  • The framework is removed and the impression is examined for glossy and dull areas
  • Finally, place it for 12 minutes

•  Selective Pressure Technique:
  • The special tray is fabricated on the master cast
  • The tissue surface of the tray is trimmed
  • Selective Pressure is loaded with impression material
  • Selective Pressure is inserted in the patient’s mouth
  • Pressure is applied over the stress-bearing area.

Question 12. Discuss various components of removable partial dentures and the functional role of each.
Answer:

Components Of Removable Partial Denture:

1. Removable Partial Denture Major Connector:

• A removable Partial Denture is defined as “A part of a removable partial denture which connects the components on one side of the arch to the components on the opposite side of the arch”.
• Removable Partial Denture is the largest and most important component of the removable partial denture
• Removable Partial Denture forms the basic framework.

2. Removable Partial Denture Ideal Requirements:

• Removable Partial Denture should be rigid enough to uniformly distribute occlusal forces
• Removable Partial Denture should provide vertical support
• Removable Partial Denture should protect soft tissues
• Removable Partial Denture should provide indirect retention when needed It should be comfortable for the patient
• Removable Partial Denture should not allow food accumulation
• Removable Partial Denture should be self cleansable

3. Removable Partial Denture Classification:

• Maxillary:
  • Single posterior palatal bar
  • Palatal strap
  • Palatal plate
  • Antero posterior palatal bar
  • Horseshoe connector
  • Closed horseshoe
  • Complete palate
• Mandibular:
  • Lingual bar
  • Lingual plate
  • Kennedy bar
  • Sublingual bar
  • Cingulum bar
  • Labial bar

4. Removable Partial Denture Location:

• Removable Partial Denture should be placed free of movable tissue
• Removable Partial Denture should avoid impingement of gingival tissue
• Bony and soft tissue prominence should be avoided
• Relief should be provided
• The border of the major connector should be 6 mm away from gingival margins in the maxillary arch and 3 mm in the case of the mandibular arch

5. Removable Partial Denture Functions:

• Removable Partial Denture connects all the components of RPD
• Removable Partial Denture provide indirect retention

6. Removable Partial Denture Minor connector:

• Removable Partial Denture is defined as “The connecting link between the major connector or base of a removable partial denture and other units of the prosthesis, such as clasps, indirect retainers, and occlusal rests”.

7. Removable Partial Denture Types:

• The minor connector that connects the direct retainer to the major connector
• The minor connector that connects auxillary rests to the major connector
• The minor connector that connects the denture base to the major connector
• The minor connector that extends as the approach arm of a bar clasp.

Removable Partial Denture Form And Location:

• It should have sufficient bulk for rigidity
• Its thickest portion should lie on lingual surface
• It should taper in contact area to avoid sharp edges
• It should not rest in convex area rather present within embrasure

1. Functions:

• It connects the major connector to other parts
• It transmits stresses evenly to all components
• It transmits the force acting on the prosthesis to the edentulous ridge and the remaining natural teeth

2. Rest:

• “It is defined as “A rigid extension of a fixed or re- movable partial denture which contacts a remaining tooth or teeth to dissipate vertical or horizontal forces.”
• Rests are metallic extensions in the denture frame. work that extend over the occlusal/lingual surface of the supporting teeth

Function Of Rest:

To transmit the occlusal forces acting on the denture along the long axis of the abutment teeth

Classification Of Rest:

• Based On The Relation Of The Rest To The Direct Retainer
  • Primary rRest –  They are placed along with the clasp assembly
  • Secondary/Auxillary rest – These are the one placed for indirect retention

• Based On The Location Of The Rest:
  
  • Occlusal Rest
  • Cingulum/ Lingual Rest
  • Incisal Rest

• Based On The Shape And Structure Of The Rest:
  • Triangular
  • Boomerang shaped
  • Conservative circular

3. Direct Retainer:

• Direct Retainer is defined as “A clasp or attachment placed on an abutment tooth for the purpose of holding a removable denture in position”.

The Function Of Direct Retainer:

• Direct Retainer prevents the displacement of the denture
• Direct Retainer provides retention through the retentive arm of the clasp
• All components of the clasp except the retentive arm provide stability
• Direct Retainer resist the movement of the denture against the path of insertion
• Direct Retainer stabilizes the denture against horizontal movement
• The encirclement of the clasp confines it to the tooth during function

Classification of Direct Retainer:

1. Intracoronary:
   • Precision attachment
   • Semiprecision attachment
2. Extracoronal:
   • Attachment
   • Clasp assemblies
   • Suprabulge
   • Infrabulge

4. Indirect Retainers:

Indirect Retainer is defined as “a part of a removable partial denture which assists the direct retainers in preventing displacement of distal extension denture bases by functioning through lever action on the opposite side of the fulcrum”.’

Functions Of Indirect Retainers:

• Indirect Retainers counteract the lifting forces and stabilize the denture
• Indirect Retainers counteract horizontal forces and provide stability and support to the denture
• Indirect Retainers can splint and protect the anterior teeth
• Indirect Retainers may act as an auxiliary rest
• The dislodgement of the indirect retainer suggests the need of relining.

Types  Of Indirect Retainers:

• Auxillary occlusal rest
• Canine extension
• Canine rest
• Continuous bar retainer Modification areas
• Rugae support
• Direct indirect retention
• Indirect retention from major connectors

5. Denture Base:

Denture Base is defined as “that part of a complete or removable partial denture which rests upon the basal seat and to which teeth are attached”.

Requirements of Denture Base:

• Accurate tissue adaptation Thermal conductivity
• Sufficient strength
• Cleanability
• Cost-effective

Types of Denture Base:

• Acrylic
• Metal
• Combination

Functions Denture Base:

• Provide a framework for tooth adaptation
• Restores the contour of the edentulous ridge

6. Artificial Teeth attached to the denture base by the following methods

• Acrylic teeth fused with the denture base acrylic resin
  Porcelain or acrylic tube teeth are usually cemented to the metal base
  Resin teeth processed directly over the metal base
• Metal teeth are cast along with the framework
• Chemical bonding of acrylic with the metal base

Question 13. Enumerate various components of RPD and discuss in detail about the maxillary major connector.
Answer:

Components Of RPD:

• Major connector
• Minor connector
• Direct retainer
• Indirect retainer
• Rest
• Denture base
• Artificial tooth

Maxillary Major Connector Requirements:

Beading should be given to the posterior margin of the maxillary major connector to provide a seal with the soft tissue in their margin

• It should be rigid enough to distribute occlusal forces
• The border of the connector should be 6 mm away from the gingival margins
• The borders should be parallel to the gingival margins
• The borders should be rounded to avoid interference to the tongue

• The Anterior border should end in the  valley of the rugae and not on the crest

Maxillary Major Connector Types Features and Indications:

• Type 1: Single Posterior palatal bar
• Single Posterior Palatal Bar Feature And Indication:  It is a bar running across the palate
  • Single Posterior Palatal Bar Used In:
    • Interim partial denture

• Type 2: Palatal strap
  
• Palatal Strap Feature And Indication: A thin Band of Metal plate runs across the palate
  • Palatal Strap Used in:
    • Unilateral distal extension partial denture

• Type 3: Palatal plate
  
• Palatal Plate Feature And Indication:  Broader than the palatal strap 
  
  • Palatal Plate Used in:
    • Class 1
    •  ‘V’ Or ‘U’ shaped palate
    • Strong abutment
    • More than six remaining anterior teeth

• Type 4: Anterior Posterior bar
• Anterior Posterior Bar Feature And Indication: It is a combination of an anterior palatal strap and a posterior palatal bar
  • Anterior Posterior Bar Used in:
    • When anterior and posterior abutments are widely separated
    • Large inoperable tori

Anterior Posterior bar Design Procedure:

• Step 1-Outline the stress-bearing area
• Step 2- Outline the non-stress-bearing area
• Step 3 – Outline the extend of the connector
• Step 4- Select the connector based on
  • Patient’s comfort
  • Rigidity required
  • Denture base
  • Amount of indirect retention required

Step 5-Connect All The Markings:

Question 14. Add a note on various types of clasp.
Answer:

Types Of Clasp:

1. Circumferential Clasp/Aker’s Clasp:

• These clasps embrace more than half of the abutment tooth
• Circumferential Clasp prevents the rotation of the denture
• They approach the undercut from an occlusal direction

Circumferential Clasp Advantages:

• Circumferential Clasp is easy to fabricate and repair
• Circumferential Clasp leads to less food retention
• Circumferential Clasp can be best applied in a tooth-supported partial denture
• Provides excellent support and retention

Circumferential Clasp Disadvantages:

• Circumferential Clasp covers a large tooth surface area
• Alters buccolingual width of the crown Interferes with the normal food flow
• This leads to food accumulation and decalcification of the tooth structure Deprives periodontal stimulation
• Circumferential Clasp cannot be used for cases with an undercut away from edentulous space

2. Bar Clasp:

• Bar Clasp is an infra bulge clasp
• Bar Clasp approaches the undercut gingivally
• Bar Clasp has a push type of retention

Bar Clasp Parts:

• Retentive arm
  • Gingival approach arm
  • Retentive terminal
• Rest
• Shoulder
• Body
• Proximal plate
• Reciprocal arm

Bar Clasp Advantages:

• Bar Clasp Is easy to Insert
• It is more esthetic

Bar Clasp Disadvantages:

• Bar Clasp tends to collect food debris
• Bar Clasp has reduced bracing and stabilization
• Bar Clasp needs additional stabilizing units

Types Of Claps:

• T clasp
• Modified T clasp
• Y clasp
• I clasp
• Mirror view clasp
• I bar

Question 15. Discuss diagnosis and treatment planning for Kennedy’s Class 1 patient.
Answer:

Diagnosis:

1. Clinical Diagnosis:

• Periodontal Health:
  • The periodontal condition of the existing teeth should be examined
  • Clinical signs of periodontal health should be evaluated
  • Oral hygiene is evaluated
  • Mobility of teeth, if present is measured
• Occlusion of Existing teeth:
  • The teeth should have a good cusp-to-fossa relationship
  • Evaluate the alignment of teeth
  • Trauma from occlusion is evaluated
• Conservative And Endodontic Status
  • The existing teeth should be examined to rule out the presence of carious lesions, vitality of the pulp
  • The teeth should be examined for cracks, chipped corners, and fractures
• Radiological Examination
  • The bone loss should be evaluated
  • The structure of the basal bone in the denture-bearing area should be evaluated
  • Presence of periapical bone loss and furcation involvement should be examined
  • The presence of impacted teeth and submerged root stumps should be examined

2. Derived Diagnosis:

Derived Diagnosis is obtained from a diagnostic cast that is obtained from a diagnostic impression.

Derived Diagnosis Preparation:

• A stock tray of a suitable size should be selected Alginate is mixed in motion and loaded into the tray ray is inserted in the patient’s mouth
• After the material gets set, it is removed by a single-stroke
• Inspect for any void
• Disinfect the impression
• Pour the cast within 12 minutes
• Trimming of the cast is carried out
• Survey the cast

Derived Diagnosis Purpose:

• To locate the favorable and unfavorable undercuts
• To determine the need for pre-prosthetic mouth preparation
• To determine the path of insertion of the denture

Derived Diagnosis Treatment Planning:

• Treatment should be properly planned before starting the treatment
• It can be divided into six different stages

Question 16. Types of mandibular major connectors.
Answer:

Mandibular Major connector:

1. Lingual Bar Design:

• It is half pear-shaped
• Its thickest portion is placed inferiorly
• There must be 8 mm vertical clearance from the floor of the mouth
  The upper border should have 3 mm clearance from the marginal gingiva
• The minimum height should be 5 mm
• It should be as inferior as possible

Lingual Bar Design Advantages:

• Lingual Bar Design is easy to fabricate
• Lingual Bar Design has mild soft tissue contact

Lingual Bar Design Disadvantages:

• Contraindicated in the presence of Tori
• Contraindicated in short vestibule

2. Lingual Plate Design:

• The superior border extends up to the cingulum It is scalloped in between the teeth
• In the presence of large embrasures, it is made to dip down-step back design
• Anteriorly, it should be supported by rests

Lingual Plate Design Indications:

• In the absence of posterior teeth
• In the presence of periodontally weakened teeth
• In the case of a short vestibule
• In the case of resorbed ridge
• In bilateral distal extension conditions
• When additional teeth are to be added
• In the case of retrognathic jaw

Lingual Plate Design Advantages:

• Rigid, stable
• Provide indirect retention
• Provide the addition of teeth

Lingual Plate Design Disadvantages:

• Food accumulation Decalcification of teeth
• Soft tissue irritation

3. Double Lingual/Kennedy Bar Design:

• The middle portion is cut off
• The lower part is pear-shaped
• The upper part is half oval 2-3 mm high and 1 mm thick
• The upper bar should dip into the embrasure
• Two bars are connected by a minor connector

Double Lingual/Kennedy Bar Design Indications:

• Large embrasures cases
• Large diastema cases

Double Lingual/Kennedy Bar Design Advantages:

• Provide indirect retention
• Horizontal stabilization
• Allow free flow of saliva

Double Lingual/Kennedy Bar Design Disadvantages:

• Tongue interference
• Food entrapment

4. Sublingual Bar:

• Similar to the lingual bar
• It is placed more inferiorly and posteriorly

Sublingual Bar Indications:

• Short vestibular depth
• Along with the linguistic plate
• Presence of anterior lingual undercut

Sublingual Bar Contraindications:

• Lingual tori
• High frenal attachments

5. Cingulum Bar:

• The Cingulum Bar is located on or slightly above the cingula of the anterior teeth

Cingulum Bar Indications:

• Large embrasures cases
• Large diastema cases

6. Labial Bar:

• Placed on the labial surface
• Labial Bar is similar to the lingual bar, but broader and thicker

Labial Bar Indications:

• Lingually inclined teeth
• Presence of tori

Labial Bar Disadvantages:

• Poor esthetics
• Distort the lower lip
• Patient discomfort

Question 17. Classify clasps. Give the difference between gingivally and occlusally approaching clasps.
Answer:

1. Circumferential/Aker’s clasp/Occlusally Approaching:

“A clasp that encircles a tooth by more than 180°, including opposite angles, and which usually has total contact with the tooth with at least one terminal being in the infra bulge area”.

Sub-Types:

• Simple circlet clasp
• Reverse clasp
• Multiple circle clasp
• Embrasure clasp
• Ring clasp
• Fishhook or hairpin clasp
• Onlay clasp
• Combination clasp
• Back action
• Half and Half clasp
• Grasso’s clasp

2. Vertical Projection/Bar/Roach Clasp:

“A clasp having arms which are bar-type extensions from major connectors or from within the denture base, the arms pass adjacent to the soft tissues and approach the point or area of contact on the tooth in a gingival-occlusal direction”

3. Continuous Clasp:

“A metal bar usually resting on the lingual surface of teeth to aid in their stabilization and to act as an indirect retainer”.

Difference Between Occlusal Approaching And Gingival Approaching Clasp: