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Dentinal Hypersensitivity Long Essays

Question 1. Management of dentin hypersensitivity

Answer:

Management Of Dentin Hypersensitivity:

1. Home Care With Gentrifies

• Strontium chloride
• Potassium nitrate
• Fluoride

2. In-Office Treatment

• Varnishes
• Corticosteroids
• Treatment of dentinal tubules
• Burnishing of dentin
• Silver nitrate
• Zinc Chloride
• Iontophoresis
• Fluoride compounds
• Potassium oxalate
• Dentin bonding agents
• Restorative resins
• Laser

3. Patient Education

• Dietary counseling
• Tooth brushing technique
• Plaque control

Dentinal Hypersensitivity Short Essays

Question 1. Theories of Hypersensitivity.

Answer:

Theories Of Hypersensitivity:

1. Neural Theory

• States that hypersensitivity occurs due to the activation of nerve ending lying within the dentinal tubules
• Rejected because
  • Dentinal nerves do not extend beyond the inner dentin
  • A newly erupted tooth does not poses such nerve endings yet it is sensitive
  • Application of local anesthesia to exposed dentin does not eliminate dentin sensitivity

2. Odontoblastic Transduction Theory

• Assume that the odontoblast extend to the periphery
• Stimuli excite the odontoblastic process, this comes into close apposition to nerve endings and transmits excitation to it,
• Rejected because
  • Absence of synaptic relationship between odontoblast and pulpal nerves
  • There is no neurotransmitter vesicles in the odontoblastic process
  • The membrane potential of odontoblast is too low to permit transduction
  • The odontoblastic process is restricted to the inner third of dentinal tubules

3. Hydrodynamic Theory

• Proposes that a stimulus causes displacement of the fluid that exists in the dentinal tubules
• This activates the nerve endings present in the dentin or pulp

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

• Accepted because
  • When dentin is exposed, fluid can be seen
  • Profuse branching of tubules at DEJ is present to induce sensitivity

1. Neural Theory: Stimulus applied to dentin causes direct excitation of the nerve fibers
2. Odontoblastic Transduction Theory: Stimulus is transmitted along the odontoblast and passes to the sensory nerve, endings through synapse
3. Hydrodynamic Theory: Stimulus causes displacement of fluid present in dentinal tubules which further excite nerve fibers

Dentinal Hypersensitivity Viva Voce

1. The hydrodynamic theory is an accepted theory of dentinal hypersensitivity.

Non-Carious Lesion Long Essays

Question 1. Define class 5 cavity. Enumerate various materials used for restoring it. Add a note on abstraction.

Answer:

Class 5 Cavity: Caries on the gingival third of facial and lingual or palatal surfaces of all teeth

Class 5 Cavity Materials Used For Its Restoration:

• GIC
• Composite
• Silver Amalgam

Class 5 Cavity Abfraction:

• Wedge-type defects usually occur in cervical areas of the tooth due to excessive occlusal stresses or parafunctional habits

Class 5 Cavity Etiology: Occlusal loading on the tooth

Class 5 Cavity Features:

• Single tooth involvement
• Sharply defined wedge-shaped defect
• Involvement of facial surfaces
• Initially, minor irregular crack on the enamel
• Later, the notch extending into dentin

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

Management Of Abrasion, Erosion, And Abfraction:

1. Preventive:

• Correct occlusal disharmony
• Use of appliances to prevent bruxism
• Correct ill-fitting metal clasps/dentures

2. Restorative:

• Materials used
• Composite resins
• Glass Ionomer cement
• Silver amalgam

3. Endodontic Treatment

4. Periodontic Treatment

Non-Carious Lesion Short Essays

Question 1. Non-carious lesions and their management.

Answer:

Non-Carious Lesions And Their Management:

1. Erosion:  Erosion is the loss of tooth substance caused by a chemical process that does not involve known bacterial action.
2. Abrasion: Abrasion is the loss of tooth substance through some abnormal mechanical process other than tooth contact
3. Abfraction: Wedge-type defects usually occur in cervical areas of the tooth due to excessive occlusal stresses or parafunctional habits

Etiology: Occlusal loading on the tooth

Question 2. Erosion.

Answer:

Erosion:

Erosion Definition – Erosion is the loss of tooth substance caused by a chemical process that does not involve known bacterial action.

Erosion Causes:

1. Intrinsic:

• Eating disorder
• Gastrointestinal disorder
• Chronic alcoholism
• Pregnancy morning sickness

2. Extrinsic:

• Dietary origin
• Occupational
• Drug-induced – Aspirin

Erosion Features:

• Broad saucer-shaped depression
• Surface – smooth, hard, and polished
• Sensitive tooth
• Site – Gingival third of the labial surface of anterior

Question 3. Abrasion.

Answer:

Abrasion Definition:

• Abrasion is the loss of tooth substance through some abnormal mechanical process other than tooth contact

Abrasion Causes:

• Faulty oral hygiene practice
• Abnormal oral habits

Abrasion Features:

• Saucer shaped indentation
• Smooth, shiny surface
• Teeth affected – canines and premolars
• Unilateral
• Sharply defined margins and internal angles

Non-Carious Lesion Viva Voce

• Abrasion is seen as a sharp 5-shaped notch in a gingival portion of the facial aspect of the tooth
• Abfraction seen as sharp notch or wedge-shaped lesions

Veneers Important Notes

1. Indications

• To mask discoloration due to fluorosis, aging
• To correct enamel hypoplasia and hypo calcification
• To close diastema
• To correct malocclusion
• To improve aesthetics
• To correct progressive wear or fracture of anterior teeth

2. Contraindications

• Presence of inadequate enamel
• Poor quality of enamel
• Presence of habits like bruxism

3. Incisal Preparation

• Incisal Preparation Types

Veneers Short Essays

Question 1. Veneers.

Answer:

Veneers:

• Described as a layer of tooth-colored material applied on the tooth surface for aesthetic purpose

Veneers Indications:

• Defective surface
• Discolored facial surface
• Discolored restoration

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

Veneers Types:

1. Based On The Method Of Fabrication:

• Direct technique
• Indirect technique

2. Based On The Extent Of Coverage:

• Partial veneer
• Full veneer

Veneers Procedure:

• Cleaning of teeth
• Shade selection
• Isolation
• Tooth preparation
• Acid etching
• Application of bonding agent
• Placement of composite

Veneers Short Answers

Question 1. Incisal Lapping for Veneers.

Answer:

Incisal Lapping For Veneers:

Incisal Lapping For Veneers Indications:

• Crown lengthening
• Severe incisal defect

Incisal Lapping For Veneers Advantages:

• No need for temporary restoration
• Improved esthetics

Question 2. Direct Veneer.

Answer:

Direct Veneer:

Direct Veneer Indications:

• Localized discoloration

Direct Veneer Advantages:

• Single appointment
• Economical

Direct Veneer Disadvantages:

• More chair time
• More labor

Veneers Viva Voce

1. Veneer placement is time-consuming
2. Indirect veneers are attached to enamel by acid etching and bonding with resin.

Bonding Important Notes

1. Bonding Systems

• Enamel bonding system
• Dentin bonding system
• Amalgam bonding system

2. Enamel Bonding System

• Consist of unfilled liquid acrylic BIS-GMA resin monomer mixture placed onto acid etched enamel
• Steps:
  • Acid etching by 37% phosphoric acid
    • Results in the formation of resin tags
    • A concentration greater than 50% results in the formation of monocalcium phosphate monohydrate that prevents further dissolution
    • Below 30% results in the formation of dicalcium phosphate dehydrate that cannot be easily removed
    • The length of application of the etchant is 15 seconds
    • Increased in fluoride-treated teeth and primary teeth
  • Etched enamel is rinsed with water for 20 seconds
  • Next enamel bonding agent is applied to the etched surface

3. Dentin Bonding System

• Consist of unfilled liquid acrylic BIS-GMA resin monomer mixture placed onto acid-conditioned dentin surface
• Dentin bonding is difficult because
  • Dentin tissue contains plenty of fluids
  • Presence of a smear layer
  • Chemical effects on the pulp
• Steps:
  • Step 1 – Etching/ conditioning
    • Conditioners are agents that aid in the removal or modification of the smear layer
  • Step 2- Application of primer
    • Primers are hydrophilic monomers which are applied over the etched surfaces for easy flow of bonding agents
  • Step 3 – Application of bonding agent
    • Dentin bonding agents are unfilled resins that help in the formation and stabilization of hybrid layer

4. Amalgam Bonding Systems

• Amalgam Bonding Systems is used to bond
  • Amalgam to tooth
  • Amalgam to amalgam
  • Amalgam to other metal substrates

5. Dentin Bonding Agents – Generations

6. Bond Strength Of Various Bonding Systems

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

Bonding Short Essays

Question 1. Acid etching.

Answer:

Acid Eetching:

• Acid etching is the process of increasing the surface reactivity by demineralizing the superficial calcium layer and thus creating enamel tags.
• These tags help in micro-mechanical bonding between the tooth and restorative resin.

Acid etching Mechanism:

• Cleanses debris
• Increases enamel surface area
• Produces micropores for mechanical interlocking
• Exposes more reactive surface layer

Factors Affecting It:

• Form of acid-gel
• The concentration of acid – 37% phosphoric acid
• Time – 15-20 sec.
• Chemical nature of enamel
• Type of dentition

Acid etching Technique:

• Oral prophylaxis
• Isolate the tooth
• Application of etchant for 15 seconds
• Rinse thoroughly for 5-10 seconds
• Dry it which results in a frosty, white appearance
• Apply enamel bonding agents

Question 2. Dentin Bonding agents.

Answer:

Bonding Agents:

• Denting bonding agents have both hydrophilic and hydrophobic ends
• The hydrophilic end displaces dentinal fluid while the hydro-phobic end bonds to the composite resin

Bonding Short Answers

Question 1. Hybridization.

Answer:

Hybridization:

• Given by Nakabayachi
• Hybridization is a process of the formation of resin
• Important in micromechanical bonding
• Conditioning the dentinal surface exposes the collagen fibrin network with microporosities
• These spaces are filled with low-viscosity monomers when the primer is applied.

Question 2. Hybrid Layer.

Answer:

Hybrid Layer:

• The layer formed by the demineralization of dentin infiltration of monomer and subsequent polymerization is called a hybrid layer

Zones:

1. Top Layer – Loosely arranged collagen fibrils

• Interfibrillar spaces filled with resin

2. Middle Layer – Replacement of hydroxyapatite crystals by resin monomer

3. Bottom Layer-Unaffected dentin

Question 3. Smear Layer.

Answer:

Smear Layer:

Definition:

• Smear Layer is defined as any debris calcific in nature, produced by reduction or instrumentation of enamel, dentin, or cementum.
• Depth – 1-5 pm

Components:

• Inorganic:
  • Tooth Structure
  • Nonspecific inorganic contaminants
• Organic:
  • Coagulated proteins
  • Necrotic pulp tissues
  • Saliva, blood cells
  • Micro-organism
• Role:
  • The physical barrier for bacteria
  • Diffusion of molecules
  • Resistance to fluid movement

Question 4. Types and Definition of Adhesion.

Answer:

Definition Of Adhesion:

• Adhesion refers to the forces between atoms of two unlike substances when placed in intimate contact with each other

Adhesion Types:

1. Micromechanical – By formation of resin tags
2. Adsorption – Chemical bonding
3. Diffusion – Precipitation of substances
4. Combinations

Question 5. Objectives of Acid Etching.
(or)
Effects of acid etching on Enamel

Answer:

Objectives Of Acid Etching:

• Creates microporosity in the enamel
• Increases surface area of enamel
• Results in the selective dissolution of enamel
• Formation of resin tag through the penetration of resins
• Forms a mechanical bond to the enamel
• Allows the wetting of tooth surface with resin

Question 6. Self-Etching Primers.

Answer:

Self-Etching Primers:

• These are sixth-generation dentinal adhesives
• Etchant and primes are in the same bottle while the adhesive resin is in other
• Easy to manipulate
• Good bond strength to dentin
• Example. Prompt L-Pop

Bonding Viva Voce

1. After etching, the surface area increases up to 2000 times that of the original untreated surface
2. Maleic acid, citric acid, and oxalic acid are used to etch enamel and dentin
3. The bonding agent enhances the wettability of composites to etched enamel
4. Resin tags between enamel rod peripheries are called macro tags
5. Resin tags across the end of each rod are called micro tags
6. Length of micro tags – 2-5 mm
7. Most composites are hydrophobic
8. 2-HEMA and HEMA dissolved in acetone or alcohol are used as primers
9. Cast restorations bonding system uses luting cement
10. Buonocore discovered acid etching

Ceramics Important Notes

1. Composition Of Porcelain

2. Feldspar

• Feldspar is the primary constituent of porcelain
• When melted it forms a crystalline phase called leucite and a glass phase
• Leucite is the basic glass former

3. Bonding Of Porcelain To Metal Occurs By:

• Chemical bonding
• Mechanical bonding

4. Indications Of Ceramics

• Aesthetics
• Large defects or previous restorations
• Wide Faciolingual defect

5. Contraindication Of Ceramics

• Heavy occlusal forces
• Inability to maintain a dry field
• Deep subgingival preparations

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

Ceramics Short Answers

Question 1. Aluminous Porcelain.

Answer:

Aluminous Porcelain:

• Aluminous Porcelain is a ceramic consisting of a glass matrix phase and at least 35 alumina
• Introduced by Mclean and Hughes

Aluminous Porcelain Preparation:

The concentration of alumina crystals and glass powder are mixed, pre fritted at 1200°C
↓
Mixture is grounded
↓
Incorporated into the glass matrix

Aluminous Porcelain Advantages

• Increase strength, toughness, and elasticity

Aluminous Porcelain Example:

• Hi-Cream

Question 2. Castable Ceramic/Dicor.

Answer:

Castable Ceramic:

Castable Ceramic/Dicor Composition:

• 55% – Tetrasilicic fluoride crystals
• 45% – Glass Ceramic

Castable Ceramic/Dicor Advantages:

• Marginal fit
• High strength
• High surface hardness
• Wear resistance

Ceramics Viva Voce

1. Components of CAD/CAM – scanning device, CAD- computer-aided design, CAM – computer-assisted manufacture
2. Occlusal reduction – 1.5-2 mm
3. Occlusal divergence – 6-8° per wall
4. Isthmus width – 1.5 mm
5. Axial depth of proximal box – 1.5 mm
6. Cavosurface angle – 90°
7. The gingival margin of the proximal box should be placed supragingival

Glass Ionomer Cement Long Essays

Question 1. Describe the merits and demerits of GIC. Write about its application.°

Answer:

Glass-Ionomer Cements Merits:

• Chemical bonding to tooth structure
• Bio-compatible
• Good marginal seal
• Anticarcinogenic
• Translucent
• Conservative
• Less technique sensitive

Glass-Ionomer Cements Demerits:

• Low fracture resistance
• Low wear resistance
• Opaque
• Require moisture control

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

Glass-Ionomer Cements Applications:

Isolate the tooth
↓
Tooth preparation
Conservative preparation
Minimal depth
No need for a retentive feature
↓
Conditioning of tooth with 20% polyacrylic acid
↓
Manipulation Of Cement:

Use of cool, dry glass slab/paper pad along with a plastic spatula

Dispense and divide the cement powder into 2 parts

Mix individuality for 20 sec.

Total mixing time 40-60 sec.
↓
Restoration:

Carrying cement with a cement carrier

Placement into the preparation
↓
Carving
↓
Surface protection by petroleum jelly
↓
Finishing and polishing after 24 hours

Glass Ionomer Cement Short Essays

Question 1. Clinical Indications and Contraindications for GIC.

Answer:

Clinical Indications And Contraindications for GIC:

Glass-Ionomer Cements Indications:

• Restoration of Class 3, 5, and small Class 1
• Noncarious lesions
• Root caries
• Deciduous teeth
• As luting
• As liner
• Preventive restoration
• Core build-up
• Splinting
• Endodontic failure

Glass-Ionomer Cements Contraindications:

• Stress bearing areas
• Xerostomia
• Mouth breathers
• Cuspal replacement
• Areas that require aesthetics

Question 2. Uses of Glass monomers and add a note on biocompatibility.

Answer:

Uses Of Glass Monomers:

1. As Pit And Fissure Sealants

• Due to anticariogenicity and adhesive properties

2. As liners and Bases – Beneath composite and amalgam

3. As Luting Agents

• For cementation of crowns, bridges, veneers, and orthodontic bands

4. As orthodontic brackets adhesive

5. For restorations of class 3 and class 5 lesions

6. Fissure Sealing

• Use of high-viscosity GIC

7. Restoration Of Root Caries

• Due to adhesion to dentin
• Anticariogenicity
• Ease of use

8. High Caries Risk Patients

• Because of their adhesion
• Abrasion resistance
• Anticariogenicity

9. Temporary restoration

10. Core build-up

11. ART (Atraumatic Restorative Treatment)

• Used in children with poor families
• Small to moderate pit and fissure caries

Biocompatibility:

• GIC Is Biocompatible Due To
  • Polyacrylic acid is a weak acid
  • Dissociated hydrogen ions present in GIC bound to the polymer chains
  • The formation of long polymer chains prevents their penetration into dentinal tubules
  • Postoperative sensibility due to
    • Low viscosity
    • Low initial pH of the cement

Question 3. Bilayered restoration / Sandwich technique / Laminated technology.

Answer:

Bilayered Restoration:

• Developed by McLean et. al in 1985
• Refers to a laminated restoration using glass ionomer to replace dentin and composite to replace enamel
• Composite bonds micromechanically to set GIC and chemically to the HEMA.

Bilayered Restoration  Steps:

Isolate the tooth
↓
Tooth preparation
Butt joint
Bevelling of enamel margin
↓
Pulp protection using Calcium hydroxide
↓
Tooth conditioning using polyacrylic acid
↓
Placement of GIC
↓
Etching of GIC surface
↓
Coating with a dentin bonding agent
↓
Placement of composite and curing
↓
Finishing and polishing

Bilayered Restoration  Advantages:

• Resistance to microleakage
• Esthetics
• Flouride release
• Less polymerization shrinkage
• Biocompatible

Bilayered Restoration  Disadvantages:

• Technique sensitive
• Time-consuming

Question 4. Cermet Cement.

Answer:

Cermet Cement:

• Introduced by McLean and Gasser
• Cermet Cement is a fusion of glass ionomer to powder like silver or gold.

Manufactured:

• Sinter compressed pellets made from fine metal powder and glass ionomers powder at 800oC
• Ground it into fine form
  ↓
• Addition of titanium dioxide

Cermet Cement Advantages:

• Better abrasion resistance
• Higher flexure strength.

Cermet Cement Disadvantages

• Poor aesthetics

Question 5. Resin-modified glass ionomer.

Answer:

Resin-Modified Glass Ionomer:

• Introduced as Vitreband (3M)
• Incorporate the best properties of both GIC and composite resin

Resin-Modified Glass Ionomer Composition:

• Powder:
  • Fluorosilicate glass
  • Initiator
• Liquid:
  • 15-25% resin component (HEMA)
  • Polyacrylic acid
  • Water

Resin-Modified Glass Ionomer Advantages:

• Long working time
• Good adaptation
• Chemical adhesion
• Flouride release
• Improved aesthetics
• Good strength

Resin-Modified Glass Ionomer Disadvantages:

• Polymerization shrinkage
• Limited depth of cure.

Question 6. Type 2 GIC.

Answer:

• Type 2 GIC is restorative glass ionomer cement
• Type 2 GIC is further divided into

Type 2 – 1 – Restorative Esthetic:

• Used for esthetic purposes
• For classes 3, 5
• Tunnel Restoration
• The powder/liquid ratio is 3:1 or greater
• They can either be authored or resin-modified
• Has superior physical properties
• Good translucency

Type 2-2 – Restorative Reinforced Gic:

• These have metallic inclusion
• Have superior strength
• Lack esthetics

Restorative Reinforced Gic Uses:

• Core build-up
• Root caries
• Tunnel restorations
• Deciduous restorations
• Powder/liquid ratio – 3:1 or greater

Question 7. Advantages and disadvantages of Glass Ionomer cement.

Answer:

Glass Ionomer Cement Advantages:

• Chemical bonding to tooth structure
• Bio-compatible
• Good marginal seal
• Anticarcinogenic
• Translucent
• Conservative
• Less technique sensitive

Glass Ionomer Cement Disadvantages:

• Low fracture resistance
• Low wear resistance
• Opaque
• Require moisture control

Glass Ionomer Cement Short Answers

Question 1. Tunnel Preparation.

Answer:

Tunnel Preparation:

• Isolate the tooth
• Place wedge below proximal portion
• Penetrate occlusal surface – 2mm inside marginal ridge at 45° angulation
• Removal of caries
• Widen the preparation
• Placement of band
• Placement of restorative material and its condensation
• Removal of wedge and matrix
• Finishing and polishing

Question 2. Modifications of GIC.

Answer:

Modifications Of GIC:

Fiber Reinforced Glasses:

• Alumina fibers, glass fiber, silica fiber, and carbon fiber added to cement
• Improves flexure strength
• Low abrasion resistance

Metal Reinforced GIC:

• A mixture of amalgam alloy to GIC powder
• Poor esthetics
• Poor abrasion resistance

Cermet Cement:

• Sintering metal and glass powders
• Improved abrasion resistance
• Higher flexural strength

Resin Modified Glass Ionomer:

• Incorporate the best properties of both glass ionomer Cement and composite resin
• Good adaptation
• Flouride release
• Improved aesthetics

Question 3. Composition of GIC.

Answer:

Composition of GIC:

Powder:

• Silica-41.9%
• Alumina-28.6%
• Aluminium fluoride-1.6%
• Calcium fluoride-15.7%
• Sodium fluoride- 9.3%
• Aluminum phosphate- 3.8%

Liquid:

• Polyacrylic acid with copolymers with itaconic acid, maleic acid, and tricarballylic acid
• Tartaric acid
• Water

Glass Ionomer Cement Viva Voce

1. Varnishes or sealers should not be used to coat dentin if GIC is to be used as a restorative material
2. GIC adhesion is achieved partly by mechanical adhesion and partly by chemical chelation
3. To increase mechanical strength, GIC used as restoration is mixed at a higher powder-liquid ratio
4. After 24 hours the pH of GIC is 5.3
5. To increase the pH of GIC, zinc oxide is incorporated into the powder
6. Glass ionomers bond best to enamel than dentin and cementum
7. GIC shows decreasing levels of fluoride release with time
8. Powder of GIC is referred to as “ion-leachable glass”

Cast Metal Restorations Important Notes

1. Pickling

• Pickling is the process of cleaning the gold casting with 50% warm HCl
• Used to remove surface oxides from casting
• Pickling is not a routine procedure
• Used only when indicated

2. Casting Defects

• Distortion
• Surface roughness and irregularities
• Discoloration
• Porosity
  • Solidification defects
  • Trapped gases
  • Residual air

Read And Learn More: Operative Dentistry Question And Answers

3. Types Of Casting Machines

• Centrifugal Casting Machine
  • Uses centrifugal force to accelerate the flow of molten metal into the mold space
• Air pressure Casting Machine
  • Compressed gas is used to force the molten alloy into the mold

4. Types Of Cast Metal Alloys

5. Types Of Die Materials Used

• Gypsum products
• Electroformed dies
• Epoxy resins
• Divestment

6. Properties Of Base Metal Alloys

• Low density
• Low percentage elongation
• High fusing temperature
• High hardness
• Tarnish and corrosion resistance

7. Retention Forms In Cast Restorations

• Grooves
• Bevel
• Internal box
• External box
• Pins, slots, skirt, collar
• Cusp capping
• Reciprocal retention

8. Onlay

• They are partly intracoronal and partly extra-coronal types of restoration
• Onlay has cuspal protection
• Onlay is mainly indicated when the width of the lesion exceeds one-third of the intercuspal distance
• Features of cavity preparation:
  • Capping of functional cusps
  • Cuspal reduction 1.5 mm
  • The bevel used is a hollow ground long bevel in the intracoronal portion and a counter bevel in the extra coronal portion
  • Table:
    • Onlay is a transitional area between the intracoronal and extra-coronal portion
    • Onlay should be flat
    • Relieved from opposing cusps by 1.5 mm
    • There should be 3 tables prepared for each cusp in different directions
    • Onlay provides retention and resistance form
  • Shoeing of nonfunctional cusps
    • Provides retention and resistance form over the nonfunctional cusp

9. Composition Of Wax

10. Principles For Correct Spring

• Use of proper gauge of sprue
• Use of proper length of sprue
• Should be attached to the bulkiest portion of the wax pattern
• Attach it to the wax pattern with little heat to avoid distortion

11. Uses Of Casting Ring Liner

• Permits unrestricted expansion of the investment
• Acts as a cushion between rapidly cooling metal ring and the more slowly cooling investment during the casting and crystallization of gold

12. Objectives Of Burnout

• Complete removal of wax pattern
• Elimination of excess water from the investment
• Production of thermal expansion

Cast Metal Restorations Long Essays

Question 1. Classify casting defects describe mesioocclusal cavity preparation for gold inlay on a mandibular first molar.
(or)
Describe class 2 mesioocclusal cavity preparation for gold inlay on mandibular 1 molar tooth.

Answer:

Casting Defects:

• Distortion
• Surface roughness and irregularities
• Discoloration
• Porosity
  • Solidification Defects
    • Localized shrinkage
    • Micro
  • Trapped Gases
    • Pinhole
    • Gas inclusion
    • Subsurface
  • Residual Air
    • Back pressure

Class 2 Inlay Cavity Preparation

1. Initial Tooth Preparation

Occlusal Outline Form:

• Anesthetize and isolate the tooth
• Penetrate the tooth with no.271 bur from the mesial surface
• Extend upto central fissure to uninvolved marginal ridge
• Maintain a uniform pulpal depth of 1.5mm
• Preserve distal marginal ridge
• Extend up to the smooth areas of the buccal and lingual slopes of the cusps of a tooth.

Proximal Box Preparation:

• Mesial ditch cut is given using the same bur
• Width of cut 0.8mm, 0.5 mm in dentin, and 0.3 mm in enamel
• Extend it faciolingually
• Extend gingivally
• Provide 0.5mm of clearance
• Break the contact using cuts over facial and lingual walls using No.271 bur

Resistance And Retention Form:

• Flat pulpal floor
• Box-shaped preparation
• The extra thickness of gold
• Occlusal step
• Dovetail

2. Final Preparation:

1. Removal Of Remaining Caries, Old Restorative Material

• Removal of soft caries and infected dentin with a spoon excavator

2. Pulp Protection

• Use of pulp protective materials

3. Secondary Resistance And retention Forms

• Retention grooves were placed in the facial axial and in coaxial line angles using 169L carbide bur
• Bevels
• Gingival bevel 45° to the preparation
• Include one-half the width of the gingival wall
• Occlusal bevel At occlusal 1/3rd of adjacent occlusal wall
• Removes unsupported enamel

4. Inspecting, Cleaning, And Rinsing

• Clean the prepared tooth with air/water spray
• Dry it with a cotton pellet
• Inspect the angles and margins

Question 3. Define Inlay Describe the Indications, Contraindications, advantages, and disadvantages of cast gold restoration.
Answer:

Definition Of Inlay:

• An inlay is an indirect intracoronal restoration which is fabricated extra orally and cemented in the prepared tooth

Inlay Indications:

• Extensive proximal caries
• Patients with good oral hygiene and low caries index
• Postendodontic restoration
• Teeth with extensive restoration
• To maintain proper tooth contact and contour
• Presence of cast metal restoration
• Abutment teeth
• Teeth with heavy occlusal forces and attrition

Inlay Contraindications:

• Aesthetic consideration
• Patients with high caries index
• Young patients
• Periodontally weak teeth
• Extensive caries involving facial and lingual and multiple surfaces
• Low economic status
• Presence of dissimilar restoration
• Extensive occlusal wear facets

Inlay Advantages:

• Better reproduction of details
• Better wear resistant
• Biocompatible
• Strengthens remaining tooth structure
• Fewer chances of voids
• Easy to polish
• Less chair time

Inlay Disadvantages:

• Need of temporary restoration
• Expensive
• Technique sensitive
• Difficult to repair
• Weak tooth bonding
• Unesthetic

Question 4.  Give the difference in cavity preparation between amalgam and gold inlay.

Answer:

Differences In Cavity Preparation Between Amalgam And Gold Inlay:

Question 5 Define retention form. How it is achieved in cast restoration.

Answer:

Retention Form:

• Retention Form is that form of cavity that resists the displacement of restoration from tipping and lifting forces

Retention In Cast Restorations:

1. Grooves:

Resist lateral displacement of restoration

• Internal Grooves
  • Indicated in a shallow and small cavity
  • Contraindicated in a deep cavity
• External Grooves
  • Indicated in extra coronal preparation
  • Prevents dislocation
  • May be prepared in stepped form

2. Reverse Bevel:

• Indication Class 1, 2, 3 restoration
• Presence of sufficient gingival floor
• Placed over the gingival floor with an incline gingivally and axially

3. Internal Box:

• Indicated in the presence of sufficient dentin
• Contraindicated in class IV and V preparation
• Have vertical walls prepared in dentin
• Increases retention
• It should be 2 mm in dimension

4. External box:

• Box with an opening to the axial surface of the tooth
• The peripheral portion can be flared/beveled

5. Pins:

• Types of pins used Cemented, threaded, parallel, cast, and wrought

6. Slot:

• Indicated in the shallow cavity, restricted occlusal anatomy
• Have a depth of 23mm

7. Skirt:

• Indicated in missing wall

8. Collar:

• Depth 1.52mm, surface extension
• Indication Grossly carious teeth
• Short teeth

9. Cusp Capping:

• Provide sufficient height of cusp

10. Reciprocal Retention:

• Placement of retention made at every end of the preparation

Question 6. Discuss the causes of casting defects and their prevention.

Answer:

The Causes Of Casting Defects And Their Prevention:

• Casting defects can be prevented by following various steps systematically
• Types of casting defects along with their causes and prevention are as follows

Cast Metal Restorations Short Essays

Question 1. Bevel and flares.
or
Circumferential Tie.

Answer:

Circumferential Tie:

• Circumferential Tie refers to the design of the cavosurface margin of an inlay tooth preparation

Significance:

• The cavosurface margin is the weakest part of the restoration
• To strengthen it, it is designed by incorporating bevels and flares

1. Bevels:

• Bevels is the inclination that one surface makes with another when not at right angles

Bevels Types:

• Partial Bevel
  • Involving less than 2/3rd of enamel
  • Use of type 1 casting alloys
• Short Bevel
  • Involves full thickness of enamel
  • Use of type 1 and 2 alloys
• Long Bevel
  • Involves full enamel and half dentin
  • Use in type 1, 2, and 2 alloys
• Full Bevel
  • Involves complete enamel and dentin
  • Hollow ground Bevel
  • Concave in shape
• Counter Bevel
  • In cases of cusp capping

1. Flares: They are concave/flat peripheral portions of the facial/lingual proximal walls

Question 2. Die materials.

Answer:

Die materials Properties:

• Compatible with impression materials
• Have smooth surface
• Have adequate strength
• Easy to fabricate
• Have contrasting color
• Reproduce accurate details

Die materials Materials:

Question 3. Direct Wax Pattern.

Answer:

Direct Wax Pattern:

• Prepared in the oral cavity
• Done using matrix band or without it

Direct Wax Pattern Technique:

Isolate the tooth
↓
Apply band and retainer
↓
Soften inlay wax
↓
Compress over the prepared tooth
↓
Hold it with finger pressure til it sets
↓
Burnish it
↓
Remove band and retainer
↓
Check for centric occlusion
↓
Check for high points
↓
Smoothen it
↓
Attach sprue former and reservoir
↓
Remove the wax pattern

Direct Wax Pattern Advantages:

• Fewer discrepancies
• Less laboratory work

Direct Wax Pattern Disadvantages:

• Require more skill
• Requires more chair side time

Question 4. Indirect Wax Pattern.

Answer:

Indirect Wax Pattern:

• Prepared outside the oral cavity
• Use of type 11 inlay wax

Indirect Wax Pattern Steps:

Lubricate the die
↓
Adapt inlay wax over it
↓
Carve the wax
↓
Attach sprue former
↓
Remove the wax pattern

Indirect Wax Pattern Advantages:

• Less chair time
• Finishing and polishing
• This can be done on a die

Indirect Wax Pattern Disadvantages:

• More laboratory work
• Errors due to inadequate casting

Question 5. Sprue.

Answer:

Sprue:

• Provides a channel so that molten metal flows into mold space after the wax pattern has been eliminated.

Sprue Types:

• Wax
• Plastic
• Metal

Sprue Functions:

• Provides a channel for the flow of molten alloy
• Provides reservoir to compensate for shrinkage
• Provides a channel for wax elimination

Sprue Requirements:

• Diameter Greater than the thickest part of the wax pattern
• Attachment to the thickest part of the wax pattern
• Sprue length such that the end of the wax pattern is l/8th to l/4th inch away from the open end of the casting ring
• Direction 45 to the bulkiest portion of the wax
• ReservoirTo compensate shrinkage

Question 6. Casting machines.

Answer:

Casting machines Types:

1. Centrifugal Casting Machine:

• Cheapest
• Used for small casting
• Uses centrifugal force to accelerate the flow of mol¬ten metal into the mold space

Casting Machines Steps:

Heat the ring at 1200°F for 15 minutes
↓
Move the arm of casting machine 23 turns clockwise and
lock it
↓
Heat the gold alloy
↓
Place the ring in the casting machine
↓
Release the lock of the arm
↓
This forces molten gold into a mold
↓
Recover the ring from the casting machine and cool it
↓
Removes the casting and cleans it

2. Air pressure Casting Machine:

• Compressed air/gases like carbon dioxide or nitrogen are used to force the molten alloy into the mold.

Question 7. CADCAM for Inlay.

Answer:

CADCAM For Inlay:

• CADCAM indicates Computer Aided Design Computer Aided Machine
• In it, the whole casting design is fabricated
• This design is fed up with the computer
• The whole design is scanned
• It is then fabricated into the final prosthesis
• The computer is connected to a machine that processes the prosthesis
• Thus, the machining process of the prosthesis according to the design fabricated by the computer

Question 8. Types of Cast Gold Alloys.

Answer:

Types of Cast Gold Alloys:

Type 1 Soft

• Used for fabrication of small inlays
• Low strength
• Easily burnished
• Gold content7583%

Type 2 Medium

• Used for fabrication of inlays and onlays subjected to moderate stresses
• Cannot be heat treated
• Gold content7075%

Type 3Hard

• Used for high-stresses
• High strength
• Can be heat-treated
• Gold content6570%

Type 4 Extra Hard:

• Used for crowns, bridges, and removable partial dentures
• Increased hardness
• Can be heat-treated
• Gold content 60%

Question 9. Indications and contraindications of Onlay

Answer:

Indications And Contraindications Of Onlay:

Only:

• Indications And Contraindications Of Onlay is a combination of intracoronal and extra-coronal cast restoration which covers one or more cusps

Indications And Contraindications Of Onlay Indications:

• Extensive weakened tooth due to caries or large restoration
• As post-endodontic restoration
• Presence of other cast restorations in adjacent or opposing teeth
• When the mesiodistal diameter of the tooth needs to be extended
• To correct the occlusal plane
• As an abutment for RPD

Indications And Contraindications Of Onlay Contraindications:

• Patients with high caries rate
• Young patients
• Short clinical crown height

Cast Metal Restorations Short Answers

Question 1. Reverse bevel.

Answer:

Reverse Bevel:

• A reverse bevel is a bevel of generous width that is prepared on the facial margin of a reduced cusp with a flame-shaped, fine grit diamond instrument
• Reverse Bevel width should extend beyond any occlusal contact with opposing teeth
• Reverse Bevel should be at an angle that results in a 30-degree marginal metal
• Reverse Bevel should be wide enough so that the cave surface margin is beyond any contact with the opposing dentition

Question 2. Sprue former.

Answer:

Sprue Former:

• A sprue former is made of wax, plastic, or metal
• Thickness is in proportion to the wax pattern

Sprue Former Functions:

• To form a mount for the wax pattern
• To create a channel for the elimination of wax during burnout
• Forms channel for entry of metal which compensates for allo£ shrinkage during solidification

Question 3. Porosities in casting.

Answer:

Porosities In Casting:

Porosities In Casting Types:

1. Caused By Solidification Shrinkage

• Localized shrinkage porosity
• Suck back porosity
• Microporosity

2. Caused By Gas

• Pinhole porosity
• Gas inclusion
• Subsurface porosity

3. Caused By Air Entrapment:

• Back pressure porosity

Porosities In Casting Prevention:

• Use of correct sprue thickness
• Correct placement of sprue
• Use of reservoir
• Use of adequate casting forces
• Use of porous investment and proper vents
• Place the pattern away from the end of the ring

Question 4. Inlay Taper.

Answer:

Inlay Taper:

• Ideally, a tooth preparation should have slight diverg¬ing walls from gingival to occlusal surface

Inlay Taper Value:

• Optimal taper25° per wall
• For short longitudinal walls 2° taper
• For high longitudinal walls Increased but not more than 10°
• Preparation should never have one side with more taper than the other
• For shallow preparation Axis of the taper is parallel to the long axis of the tooth
• For class 5 Axis of the taper is perpendicular to the long axis of the tooth.

Question 5. Hot spot porosity.

Answer:

Hot Spot Porosity:

• Hot Spot Porosity is localized shrinkage porosity
• Occurs due to shrinkage of molten alloy when alloy solidifies from a molten state
• Cause Sprue former directed at 90°
• Prevention Direct the sprue former at 45°

Question 6. Back pressure porosity.

Answer:

Back Pressure Porosity:

• This is caused by inadequate venting of the mold
• If the bulk of the investment is too great the escape of air becomes difficult causing increased pressure in the mold
• The gold will solidify before the mold is filled resulting in a porous casting with rounded short margins
• Avoided by
  • Using adequate casting forces
  • Use of investment of adequate porosity
  • Place the pattern not more than 68 mm from the end of the ring

Question 7. Subsurface porosity.

Answer:

Subsurface Porosity:

• Subsurface Porosity is porosity caused by gas

Subsurface Porosity Cause:

• Simultaneous nucleation of solid grains and gas bubbles

Subsurface Porosity Prevention:

• Controlling the flow of molten alloy

Question 8. Electroformed dies.

Answer:

Electroformed Dies:

Subsurface Porosity Advantages:

• Dimensional accurate
• Hard, abrasion-resistant
• Imparts a smooth surface
• Cheap
• Better marginal definition
• Does not absorb oil or water
• Prevent cuspal wear

Subsurface Porosity Disadvantages:

• Difficult to trim
• Silver bath health hazard
• Noncompatible with impression material
• Color contrast is not good
• or adaptation to wax
• The pattern tends to lift from margins

Question 9. Onlay.

Answer:

Onlay:

• Onlay It is a combination of intracoronal and extra-coronal cast restoration which covers one or more cusp

Tooth Preparation:

• Occlusal Outline Form:
  • Isolate the tooth
  • Start preparation with 271 bur
  • Maintain a pulpal depth of 2 mm
  • Reduce the cusps
  • Occlusal divergence 3°-5°

Proximal Box Preparation:

• Extend the preparation both mesially and distally

Question 10. Inlay Wax.

Answer:

Inlay Wax:

Inlay Wax Properties:

• Plasticity
• Solid below approximately 40°C

Inlay Wax Types:

• Type 1
• Type 2

Inlay Wax Composition:

• Paraffin wax- 40 60%
• Ceresin -10%
• Gum dammar- 1%
• Carnauba- 25%
• Coloring agents

Question 11. Localized shrinkage porosity

Answer:

Localized Shrinkage Porosity:

• Occurs when cooling is incorrect
• The sprue freezes before the rest of the casting
• It results in large irregular voids near the sprue casting interface

Localized Shrinkage Porosity Prevention:

• Sprue former should be directed at 45 degrees
• Placement of reservoir

Cast Metal Restorations Viva Voce

1. Sprue former diameter is between 8018 gauge
2. Types of sprue former wax, metal, and resin
3. Occlusal bevel in inlay3045°
4. Gingival bevel in inlay 30°
5. The sprue is placed at a 45° angle to the wax pattern
6. Wax interocclusal records help check occlusal clearance
7. Binder present in investment provides strength
8. Casting ring liner helps in permitting the expansion of mold
9. Sprue should be positioned in the thickest portion of the wax pattern
10. There should be a minimum gap of 1/8 1/4th inch between the ends of the casting ring and wax pattern
11. Back pressure porosity is caused by the entrapped air in the mold that does not escape through the pores of the investment
12. Type 1 or type B wax is used for the direct technique of wax pattern construction
13. Type C is used for indirect technique

Isolation Operative Dentistry Important Notes

1. Components Of Rubber Dam

• Rubber Dam Sheet
• Rubber dam clamp/ retainer
• Rubber dam frame
• Rubber dam punch
• Rubber dam retainer force
• Dental floss
• Template

Isolation Operative Dentistry Long Essays

Question 1. Enumerate various methods of Isolation. Describe in detail about rubber dam.

Answer:

Methods Of Isolation:

• Isolation Direct Method
  
  • Rubber dam Cotton rolls
  • Gauze piece Absorbent
  • wafers Suction devices
  • Gingival retraction cord
• Isolation Indirect Method
  • Local anesthesia Drugs
  • Anti sialogogues
  • Anti-anxiety
  • Muscle relaxants

Rubber Dam – By Dr. S.C. Barnum

Isolation Purpose:

• Control of moisture
• Retraction
• Protects soft tissues
• Improves quality of treatment

Isolation Contraindications:

• Asthmatic patients
• Allergy to latex
• Mouth breathers
• Extremely malpositioned tooth
• Third molar

Isolation Components:

1. Rubber Dam Sheet:

• Square sheets
• Size – 5″x 5” or 6″ x 6″

Isolation Thickness:

• Thin – 0.006″
• Medium – 0.008″
• Heavy -0.010″
• Extra heavy- 0.012″
• Special heavy – 0.014″

Isolation Color:

• Green/blue
• The dull side faces the operator

2. Rubber Dam Clamps/Retainers:

To secure the dam to the teeth

Rubber Dam Clamps Parts:

• 2 jaws
• Bow – connecting jaws
• 4 prongs – 2 on each jaw

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

• Rests on line angle

Rubber Dam Clamps Types:

• Winged or wingless retainer
• Large, small, universal

3. Rubber Dam Retainer Forceps:

• Hold the retainer
• Facilitates its placement and removal

4. Rubber Dam Frame:

• U shaped frame
• Types – metal or plastic
• Has minute projections on its outer surface to secure the dam

5. Rubber Dam Punch:

• For making holes in the dam
• Depending on the applied tooth, the sizes of the holes vary

6. Rubber Dam Template:

• Used to transfer the markings to the sheet

7. Dental Floss:

• To prevent accidental aspiration of the clamp

Rubber Dam Clamps Placement:

Comfortable position of the patient
↓
Selecting the appropriate clamp and sheet
↓
Punching a hole in the sheet
↓
Applying lubricant
↓
Holding clamp through forceps
↓
Placement of rubber dam

• The clamp is placed first and then the sheet is passed over it
• Placement of sheet and then securing it with clamp
• Both are placed together

Rubber Dam Clamps Removal:

Removal of clamp
↓
Stretching of sheet
↓
Cut all interseptal rubbers
↓
Remove the remaining

Question 2. Discuss the importance of isolation and various methodds used to achieve the same.

Answer:

Importance Of Isolation:

• Isolation helps for following

1. Moisture Control

• It refers to excluding sulcular fluid, saliva, and gingival bleeding from the operating field

2. Retraction And Access

• It provides maximal exposure of the operating site

3. Harm Prevention

• Prevents harm to the patient during the operation
• Small instruments and restorative debris can be aspirated or swallowed
• Provides patient comfort and operator efficiency

Isolation Direct Method:

1. Cotton Rolls:

• Moisture absorbent
• Provide minimal retraction

Isolation Types:

• Manual and prefabrication
• Stabilized by cotton roll holder

Site Of Placement:

• Maxillary anteriors – Either side of labial frenum
• Mandibular anterior
• Lingual sulcus
• On either side of labial frenum
• Maxillary posterior – Adjacent vestibules
• Mandibular posterior
• Buccally – vestibule
• Between tongue and teeth
• Moistened it before removal to avoid tearing off of gingiva

2. Gauze Pieces:

• Size – 2″ x 2″

Gauze Uses:

• To isolate larger areas
• As throat screens

Gauze Advantages:

• Better tolerated
• More acceptable
• Less adhesion to dry tissues

3. Absorbent Wafers:

• Made of cellulose
• Covers parotid ducts

4. Evacuators:

Evacuators Type:

• High vacuum
• Low vacuum
• High vacuum
  • Removes debris from the working site
  • Removal of toxic material
  • Decreases treatment time
• Low Volume [Saliva ejectors)
  • Used along with operative procedures

Types:

• Disposable plastic tips
• Autoclavable metallic tips

5. Gingival Retraction Cord:

• Inserted into gingival sulcus
• Retracts gingiva

Gingival Retraction Cord Types:

• Braided and non-braided
• Plain and impregnated

Gingival Retraction Cord Effects:

• Improved accessibility and visibility
• Protects gingival from abrasion
• Restricts placement of restoration into sulcus
• Everts gingival tissue

Indirect Method Of Isolation:

• It includes

1. Anaesthetic agents

2. Antisialogogues

• Chemical agent is administered orally 1-2 hours prior to the procedure

Indirect Method Of Isolation Effect:

• Causes temporary dry mouth by acting on sympathetic nervous system

Indirect Method Of Isolation Drug Of Choice:

• Atropine 0.1-1 mg

Indirect Method Of Isolation Contraindicated:

• Nursing mothers
• Patients with glaucoma

Indirect Method Of Isolation Advantage:

• Useful in hypersalivation

Indirect Method Of Isolation Disadvantages:

• Tachycardia
• Dilatation of pupils
• Urinary retention
• Sweat glands inhibition.

Isolation Operative Dentistry Short Essays

Question 1. Gingival Retraction/ Gingival tissue management.

Answer:

Gingival Retraction:

Gingival Retraction Methods:

1. Physicomechanical:

• Rubber Dam
  • Heavy, extra heavy, and special heavy sheets provide adequate mechanical displacement of gingival tissue
• Wooden Wedges – Used interdentally
• Gingival Retraction Cords
  • Displaces gingival laterally and apically

Gingival Retraction Placement:

• Anesthetize the area
• Select appropriate cord
• Pack the cord with cord tucking instrument, around the tooth
• Place it for 5 minutes
• Remove the cord after moistening it to avoid gingival abrasion
  • Rolled Cotton Twills
    • Laterally displaces gingival
    • Combined with ZOE

2. Chemical Means:

Chemical Used:

• Trichloroacetic acid
• Sulfuric acid

Advantage:

• Hemostatic

Disadvantage:

• Caustic
• Irritant

3. Chemico Mechanical Method:

Chemical Used:

• Vasoconstrictors – Epinephrine
• Astringents – Tannic acid
• Tissue coagulant – Silver nitrate

4. Rotary Curettage (Gingettage):

• Removes a minimal amount of gingival epithelium with the help of a high-speed handpiece and bur.

5. Electrosurgical Method:

• Alternating electric current energy is used at a high frequency

Actions:

• Cutting
• Coagulation
• Fulguration
• Desiccation

Question 2. Advantages of Rubber Dam.

Answer:

Advantages Of Rubber Dam:

• Maximizes access and visibility
• Protection of soft tissues
• Provides clean and dry field
• Avoids contamination
• Prevents aspiration of foreign bodies
• Improves efficiency
• Improves properties of dental material
• Protection of patient and dentist

Isolation Operative Dentistry Short Answers

Question 1. Gingival retraction cord.

Answer:

Gingival Retraction Cord:

• Inserted into the gingival sulcus
• Retracts gingiva

Gingival Retraction Cord Types:

• Braided and non-braided
• Plain and impregnated

Gingival Retraction Cord Effects:

• Improved accessibility and visibility
• Protects gingival from abrasion
• Restricts placement of restoration into the sulcus
• Everts gingival tissue

Question 2. Affected and infected Dentin.

Answer:

Affected And Infected Dentin:

1. Infected Dentin

• Irreversible denatured collagen
• Infiltrated with bacteria
• Notremineralizable
• Should be removed
• Darker
• Softer
• Lacks sensation
• Indistinct cross bands
• Stained With:
  • 0. 2% propylene glycol
  • 10% acid red solution
  • 0. 5% basic Fuschia

2. Affected Dentin

• Reversible denatured collagen
• Not infiltrated
• Remineralize
• Left behind while the cavity
• preparation
• Lighter
• Harder
• It is sensitive
• Distinct cross bands
• Cannot be stained with any solution

Isolation Operative Dentistry Viva Voce

1. Thinner rubber dam can pass through contacts easily
2. A thicker rubber dam is more effective in retracting tissues and more resistant to tearing
3. The jaws of the retainer should not extend beyond the mesial and distal line angles of the tooth
4. The bow of the retainer should be tied with dental floss
5. The tip of the saliva ejector must be smooth and of non-irritating material
6. Gingival cord placement should not harm gingival tissue
7. Atropine used for isolation is contraindicated in nursing mothers and patients with glaucoma

Direct Filling Gold Short Essays

Question 1. DFG (Direct Filling Gold).
Answer:

DFG (Direct Filling Gold):

Direct Filling Gold Definition:

• Direct gold is a gold restorative material that is manufactured for compaction directly into prepared cavities

Direct Filling Gold Indications:

• Class 1 cavities Small carious lesions in pit and fissures of posterior teeth
• Class 5 carious lesions
• Class 3 cavities proximal surfaces of anterior teeth
• Class 2 restoration of small cavitated proximal surfaces of posterior teeth
• Class 6 Incisal edges or cusp tips
• A defective margin of cast metal restoration

Direct Filling Gold Contraindications:

• Very large pulp chambers
• Severely periodontally weakened teeth with questionable prognosis
• In handicapped patients
• Root canal-filled teeth

Direct Filling Gold Classification:

1. Foil:

• Sheet
  • Cohesive
  • Noncohesive
• Ropes
• Cylinders
• Laminated foil
• Platinized foil

2. Electrolytic Precipitate:

• Mat gold
• Mat foil
• Gold calcium alloy

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

Question 2. Types Of Gold.

Answer:

Types Of Gold:

1. Gold Foil Oldest Form:

Types:

1. Sheets Size 10 x 10 cm

• Thickness 1.5 micron
• No.3 weighs 3 gm
• Too large for use in preparation

2. Gold Foil Cylinder

• Uses noncohesive gold
• Uses % and 1/8 of a sheet of gold

3. Gold Pellets

• Are annealed before the formation
• Stored in a gold foil box along with a cotton dipped in 18% ammonia

4. Platinized Gold Foil

• Platinum content in foil is 15%
• Increased hardness
• Used for restoration of cusp tips and incisal edges

5. Corrugated Gold Foil.

• Paper placed between foil gets burnt and charred

4. Laminated Gold Foil:

• More resistant to applied forces

2. Crystalline Gold

1. Mat Gold

• Electrolytically precipitated type
• Used for building up of internal restoration

2. Mat Foil

• No need to veneer the restoration

3. Electralloy

Increased hardness and strength of gold by adding minute quantities as Calcium

Improved handling properties

4. Powdered Gold

• Size 15 microns
• Difficult to handle
• Does not require very sharp line angles and point angles.

Question 3. Mat Gold.

Answer:

• Electrolytically precipitated

Mat Gold Preparation:

• Sinter pure gold in the oven
• Heat slightly below its melting point

Mat Gold Result:

• Spongy, loosely arranged crystalline structure
  • Available in form of strips
  • Can be used plain/sandwiched in gold foil
• Mat Gold Use: Building up of internal restoration
• Mat Gold Advantage: Easily compacted
• Adapted well

Question 4. Condensation of DFG.

Answer:

Condensation Of DFG:

Condensation Of DFG Aims:

• Formation of cohesive mass
• Adaptation to the preparation margins
• Prevent voids formation
• Increases strength and hardness of restoration

Condensation Of DFG Technique:

• Place the gold piece in the corner of the preparation
• Start malleting in the center of the mass
• Condense at 45o to walls and floor for maximum adaptation
• Next condense at 90° to the previous layer to prevent displacement of already condensed pieces
• Each time the condenser should overlap the half of previous step for reducing voids formation
• This is called stepping

Question 5. Annealing/Degassing.

Answer:

Annealing:

• Annealing involves the removal of the volatile protective coating present on a pure gold surface
• Used for noncohesive gold, as a layer of ammonia is present over it to prevent the formation of the oxide layer and contaminate gold

Annealing Methods:

1. Using Alcohol Flame:

• Bulk Method:
  • Place mass of gold in mica tray and heat over flame up to 650700°C
  • Less time required
  • Risk of overheating
• In The Piece Method;
  • Hold small pieces over a blue flame of alcohol and heat until the gold becomes dull red
  • Less wastage
  • Time consuming

2. Electric Annealer:

• Gold is heated for 10 minutes at 850°F
• Then cooled for placing in the prepared tooth

Direct Filling Gold Short Answers

Question 1. Preparation of Pure gold foil.

Answer:

Preparation Of Pure Gold Foil:

• Gold foil are cut into sheets
• These sheets are separated by papers
• These are heated together
• 20 such papers are consist in the book
• These sheets are cut into different sizes and are available in different weight

Question 2. Properties of DFG (Direct Filling Gold)

Answer:

Properties Of DFG (Direct Filling Gold):

• Direct Filling Gold soft, malleable, and ductile
• Direct Filling Gold does not get oxidized
• Direct Filling Gold is yellowish, metallic in color
• Direct Filling Gold get fuses at 1063oC and boils at 2200oC
• The density of gold is 1919.3 g/cm2
• Direct Filling Gold hardness is 25 BHN
• Direct Filling Gold coefficient of thermal expansion is 14.4 x 106/oC which is more than that of a tooth
• Direct Filling Gold is the noblest of all metals
• Direct Filling Gold has high thermal conductivity
• Direct Filling Gold can be cold welded
• Direct Filling Gold results in good marginal integrity

Question 3. Electrically.

Answer:

Electrically:

• The newest form of DFG

DFG Preparation:

• Electrolyte it along with the addition of minute quantities of calcium
• The resultant crystalline structure is sandwiched between two gold foils

DFG Advantages:

• Improved handling properties
• Produces the hardest surface
• Increased strength and hardness

Question 4. Gold Foil.

Answer:

Gold Foil:

Gold Foil Types:

1. Sheets Size 10 x 10 cm

• Thickness 1.5 micron
• No.3 weighs 3 gm
• Too large for use in preparation

2. Gold Foil cylinder

• Uses noncohesive gold
• Uses % and 1/8 of a sheet of gold

3. Gold Pellets

• Are annealed before the formation
• Stored in a gold foil box along with a cotton dipped in 18% ammonia

4. Platinized Gold Foil

• Platinum content in foil is 15%
• Increased hardness
• Used for restoration of cusp tips and incisal edges

5. Corrugated Gold Foil

• Paper placed between foil gets burnt and charred

6. Laminated Gold Foil

• More resistant to applied forces

Direct Filling Gold Viva Voce

1. All types of DFG except non corrosive gold require degassing before use
2. Underheating fails to render the gold surface pure
3. Overheating makes the gold more brittle
4. Poor resistance form can result in tooth fracture
5. Improper retention form results in loose restoration
6. Forces of condensation should be at 45° to the cavity walls and floors
7. Forces of condensation must be at 90° to previously condensed gold

Pin Retained Restoration Important Notes

1. Types Of Pin-Retained Restorations

2.  Failures Of Pin Retained Restorations

• If the failure is within the restoration, the restoration can fracture
• If the failure is at the interface between the pin and the restorative material, the pin can pull out the restorative material
• If the failure is within the pin, the pin can fracture when stressed beyond its ultimate tensile strength
• If the failure is at the interface between the pin and the dentin the pin can pull out the dentin
• Within the dentin, the dentin can fracture

Pin Retained Restoration Short Essays

Question 1. Pin retained restoration.

Answer:

Pin Retained Restoration:

Pin Retained Restoration Definition:

Any restoration that requires the placement of pin/pins in the dentin to provide sufficient retention and resistance from the restoration

Pin Retained Restoration Advantages:

• Conserves tooth structure
• Increases resistance and retention
• Economic
• Requires fewer recall visits

Pin Retained Restoration Disadvantages:

• Dentin fracture
• Decreased strength of amalgam
• Perforation
• Microleakage

Pin Retained Restoration Indications:

• Grossly carious teeth
• Full coverage restoration
• Extended preparation

Pin Retained Restoration Contraindications:

• Occlusal problems
• Aesthetic problems

Pin Retained Restoration Pins:

• Types- Cemented pin
• Self threaded
• Friction locked pin

Pin Retained Restoration Sizes:

• Minuta-0.015″
• Minikin – 0.019″

Read And Learn More: Operative Dentistry Short And Long Essay Question And Answers

• Minim – 0.024”
• Regular-0.031″

Pin Retained Restoration Design:

• Standard
• Self shearing
• Two in one
• Link series
• Link plus series

Question 2. Self-threaded pin./Self-threading pin.

Answer:

Self-Threaded Pin:

• Introduced by Going in 1966
• Size – 0.0015″ – 0.004” larger than pin holes
• Retention – By threads of pins
• The Material Used – Stainless steel, Titanium

Self-Threaded Pin Indications:

• Vital teeth
• Presence of sufficient dentin

Self-Threaded Pin Advantages:

• Ease of retention
• Superior retention
• No need for cement media

Self-Threaded Pin Disadvantages:

• Pulpal stress
• Dentinal crazing
• Microleakage
• Loosening of pins

Question 3. TMS (Thread mate System).

Answer:

TMS (Thread Mate System):

Thread Mate System Advantages:

• Variety of design
• Variety of pin sizes
• Good retention
• Color coding
• Gold plated
• Reduced corrosion

Thread Mate System Pin Sizes

• Minute-0.015″
• Minikin – 0.019″
• Minim – 0.024”
• Regular-0.031″

Thread Mate System Pin Design:

• Standard – 7 mm long, flat head
• Self-shearing – On reaching the bottom of the pinhole, the head separates automatically
• Two in one
• Two pins join each other at a joint
• When the peripheral pin shears off the other pin can be reused for another pin channels
• Link series
• Latch head
• Self shearing type
• Link plus series
  • Sharp threads
  • Tapered tip
  • Shoulder stop

Pin Retained Restoration Short Answers

Question 1. Self-shearing pins.
(or)
Pins in restorative dentistry.
(or)
Types of pins in amalgam restoration.

Answer:

Pins In Restorative Dentistry:

1. Direct Pins:

2. Indirect Pins:

• Smaller Than Pin Holes
  • Cast gold pins
  • Wrought precious metal pins

Pin Retained Restoration Viva Voce

1. The self-threaded pin is the most retentive
2. Cemented pins are the least retentive pins
3. Pulpal stress is maximal with self-threading pin and least with cemented pin
4. Threaded Mate System (TMS} is the most widely used self-threading pins
5. TMS pins exhibit less microleakage than other pins