Operative Dentistry

Conservative And Operative Dentistry Question and Answers

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  • Sterilisation and Infection Control Question and Answers
  • Isolation Question and Answers
  • Instruments Question and Answers
  • Separation Question and Answers
  • Matricing Question and Answers
  • Dental Caries Question and Answers
  • Pulp Protection Question and Answers
  • Fundamentals of Cavity Preparation Question and Answers
  • Amalgam Question and Answers
  • Pin-Retained Restoration Question and Answers
  • Direct Filling Gold Question and Answers
  • Cast Metal Restorations Question and Answers
  • Composite Restoration Question and Answers
  • Glass Ionomer Cement Question and Answers
  • Veneers Question and Answers
  • Ceramics Question and Answers
  • Bonding Question and Answers
  • Non-Carious Lesion Question and Answers
  • Dentinal Hypersensitivity Question and Answers
  • Minimal Intervention Dentistry Question and Answers
  • Conservative and Operative Dentistry  Miscellaneous  Question and Answers

Dental Caries Question And Answers

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Dental Caries Important Notes

1. Types of caries

  • Pit and Fissure caries
    • It occurs in pits and fissures
    • It is represented as a cone with a base towards DEJ and an apex towards the enamel surface
  • Smooth surface caries
    • It occurs in the unclean proximal surfaces
    • The base of the cone is towards the enamel surface and the apex is towards the DEJ
  • Residual caries
    • It is caries that remains in a completed cavity preparation by the operator intentionally or unintentionally
  • Forward caries
    • When the caries cone in enamel is larger than that of dentin
  • Backward caries
    • When the spread of caries along the DEJ exceeds caries in contagious enamel and caries extends into the enamel from DEJ
  • Root/senile caries
    • Occurs on the tooth that has been exposed to the oral environment
  • Recurrent/secondary caries
    • It occurs at the borders or underneath the restorations
  • Acute/rampant caries
    • The lesion is light-colored and infectious
  • Chronic/slow-caries
    • The lesion is discolored and fairly hard

2. Composition of GIC

Powder:

  • Silica 3540%
  • Alumina 2030%
  • Aluminum fluoride 1.52.5%
  • Calcium and sodium fluorides 2025%
  • Lanthanum, strontium, and barium in traces

Liquid:

  • Polyacrylic acid 45%
  • Water50%
  • Itaconic acid, maleic acid, tricarballyic acid 5%
  • Tartaric acid traces

3. Accelerators and retarders of ZOE cement

Accelerators

  • Zinc acetate
  • Alcohol
  • Water
  • Glacial acetic add

Retarders

  • Cooling of glass slab
  • Glycerine
  • Olive oil
  • Increasing liquid powder ratio

4. Hybrid or resin-modified GIC

  • BISGMA and TEGDMA are added to GIC powder and HEMA to liquid
  • They are usually light-cured, less technique-sensitive, and may be finished at the time of placement
  • The properties are superior to GIC
  • They are recommended for class V restorations and class I and II in primary teeth

5. Compomer

  • It is a combination of composite and GIC
  • Glass particles are partially silanated and are added as fillers in the composite resin
  • There is no water in the reaction
  • The properties are inferior to composites but superior to GIC and resin-modified GIC

6. Cermet

  • Glass and metal powders were sintered at high temperatures and made to react with liquid
  • It improves fracture toughness and wear resistance and maintains aesthetics

7. Sandwich or bilayered restorations

  • It uses GIC as a liner under composite restoration
  • It increases the retention form as GIC bonds to the tooth and the composite
  • Fluoride content reduces secondary caries.

Dental Caries

Dental Caries Long Essay

Question 1. Enumerate various tooth-colored restorative materials. Give manipulation, indication, and advantage of silicate.

Answer:

Various tooth-colored restorative materials:

Restorative Materials:

  • Glass ionomers
  • Composites
  • Fused porcelain
  • Acrylic resins
  • Silicate cement

Manipulation:

  • Powder/liquid ratio 1.6g/4ml
  • Dispensed on a thick, cool, dry glass slab
  • Divide it in 2/3 increments
  • Mix with agate spatula in a folded manner to obtain a homogenous mass
  • Mixing time 1 minute

Indications:

  • For anterior restoration

Advantages:

  • An anti-cariogenic property
  • Tooth color matching ability
  • Ease of manipulation

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

  • The coefficient of thermal expansion is approximately similar to enamel
  • Good insulator
  • Its compressive strength is higher than other cement

Dental Caries Short Answers

Question 1. Buccal Object Rule/Slob/Clark’s rule.

Answer:

Buccal Object Rule:

  • A standard radiograph is taken
  • Shift the cone medially/distally
  • Take a second radiograph
  • If the object is seen on the same side, the object is placed over the lingual side
  • For object localization

Question 2. Caries detecting dyes.

Answer:

1. Dyes for enamel caries:

  • Procion Staining is irreversible
  • Reacts with nitrogen and hydroxyl groups
  • Calcein Bounds with calcium
  • Zyglo ZL22 Visible by UV illumination

2. Dyes for dentin caries:

  • Infected and affected dentin layers are present
  • Basic Fuschia in propylene glycol stains only the infected dentin

Dental Caries Viva Voce

  1. Double inverted cone type of penetration of dental caries is seen in smooth surface caries
  2. Pit and fissure lesions are represented by the base of the cone facing each other
  3. The cervical to-contact area is the common site for proximal caries
  4. Smooth surface caries is mainly caused by streptococcus mutans
  5. Patients with salivary levels of streptococcus mutans above 106 CFU/ml are considered at high risk for dental caries
  6. Remineralization of carious lesions occurs at a pH above 5.5
  7. Streptococcus mutants and lactobacillus are most strongly associated with the onset of caries and active progression of cavitated lesions
  8. Root caries is initiated by A.viscosus
  9. The surface zone of enamel caries is unaffected by caries attack
  10. The Dentinoenamel junction is the least resistant to caries
  11. Increased powder in zinc phosphate cement decreases the setting time and solubility and increases strength and film thickness
  12. Zinc polycarboxylate is the first cement to show adhesion with tooth structure
  13. pH of zinc polycarboxylate liquid is 1.7
  14. Mechanical properties of ZOE cement can be improved by adding alumina to the powder and orthodoxy benzoic acid to the liquid
  15. GIC lacks toughness, and wear resistance and cannot withstand high stress
  16. ZOE and silicate cement have high solubility and disintegration rate
  17. GIC and silicophosphate have low solubility
  18. Resin cement is the least soluble in the oral cavity
  19. The working time of zinc polycarboxylate is 25 min
  20. The working time of zinc phosphate is 5 min.

Operative Dentistry Short And Long Essay Question And Answers

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Operative Dentistry Miscellaneous Short And Long Essay Question And Answers

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Miscellaneous Long Essays

Question 1. Discuss various restorative materials used to restore Class 2.

Answer:

various restorative materials used to restore Class 2:

Materials Used:

  • Composites
  • Amalgam
  • Direct filling gold
  • Metal inlay

1. Composite:

Definition:

  • It is a compound composed of at least two different materials with properties that are superior or intermediate to those of an individual component

Composition:

  • Organic matrix BisGMA or UDMA
  • Fillers Silica, barium. Zinc, Zirconium
  • Coupling agents organic silane
  • Coloring agents Titanium oxide
  • UV Absorber Benzophene
  • Initiator Camphoroquinone
  • Inhibitor Butylated hydroxyl toluene

Properties:

  • High coefficient of thermal expansion
  • Composites with higher filler content exhibit lower water absorption
  • Wear resistant
  • Radiolucent
  • Low modulus of elasticity

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

  • Water solubility 0.51.1 mg/cm2
  • Polymerization shrinkage
  • Esthetics
  • Microleakage
  • Biocompatible

2. Amalgam:

  • Composition:
    • Alloy:
      • Mercury
      • Silver 40%
      • Tin 32%
      • Copper 30%
      • Zinc 2%
      • Indium traces
    • Mercury:
      • Properties:
        • Initially, a small amount of contraction followed by expansion
        • Amalgam has a maximum compressive and tensile strength
        • Creep It is a time-dependent response
        • It leads to marginal deterioration
        • Amalgam shows tarnish and corrosion
        • Amalgam needs pulpal protection
        • Amalgam transmits temperature changes
        • It has a high coefficient of thermal expansion
        • Microleakage

3. Direct filling gold:

Properties:

  • Cohesiveness
  • Softness during manipulation
  • Malleability and ductility
  • Brinell hardness number 25
  • Tensile strength 19000 psi
  • The coefficient of thermal expansion is 14.4 x 106/°C
  • High thermal conductivity
  • The density of gold is 19.3 gm/cm3

Types:

  • Gold foil:
    • Sheets
    • Gold foil cylinder
    • Gold pellets
    • Platinized gold foil
    • Corrugated foil
    • Laminated foil
  • Crystalline gold:
    • Mat gold
    • Mat foil
    • Electrically
  • Powdered gold:

4. Metal Inlay:

Definition:

  • Inlay is an indirect intracoronal restoration that is fabricated extra orally and cemented in the prepared tooth

Advantages:

  • Better reproduction of details
  • More wear resistance
  • Biocompatible
  • Strengthen the weakened remaining structure
  • Less chair side
  • Less chances of voids
  • Easy to polish

Disadvantages:

  • Require temporary restoration
  • Expensive
  • Technique sensitive
  • Difficult to repair
  • Weak bonding to tooth structure
  • Unaesthetic

Non Carious Lesions And Management

Miscellaneous Short Essays

Question 1. Interim restoration.

Answer:

Interim restoration:

Objectives:

  • Maintain esthetics
  • Act as space maintainers
  • Allow functioning
  • Determine occlusion
  • Establish phonetics
  • Seal and insulate the prepared tooth
  • Prevent passive eruption of the tooth
  • Prevent pathologic migration

Requirements:

  • Good marginal adaptation
  • Optimal strength
  • Plaque resistant surface
  • Economical
  • Easy to manipulate
  • Dimensionally stable

Purpose:

  • Pulp protection
  • Act as a sedative
  • Soft tissue protection
  • Protect weakened tooth protection
  • Maintain the aesthetics

Materials Used:

1. For Intra coronal preparation

  • Guttapercha
  • Zinc oxide eugenol
  • Zinc phosphate
  • Zinc polycarboxylate
  • Glass ionomer
  • Calcium hydroxide

2. For extra coronal

  • Polycarbonate crowns
  • Aluminum cylinder
  • Stainless steel crowns
  • Celluloid crowns
  • Indirect acrylic restorations

Question 2. Resin Cement.

Answer:

Resin Cement:

Uses:

  • For cementation of inlays/onlays
  • For cementation of crown and bridge
  • For bonding amalgam restoration
  • For cementation of orthodontic brackets
  • For cementation of endodontic posts

Types:

  • Unfilled resin cement
  • Filled resin cement

Available Forms:

  • Powder and liquid
  • 2 paste system
  • Single paste with accelerator

Composition:

  • Powder:
    •  Resin matrix
      • B1SGMA
      • TEGDMA
    •  Fillersilica
      • Zirconia
    • Coupling agent
      • Organosilane
    • Initiator and activator
  • Liquid:
    • Adhesive HEMA:
    •  Initiator:
      • Benzoyl peroxide
  • Inorganic fillers:
    • Silica
    • Zirconia
      • Means of Polymerisation:
        • Chemical cure
        • Light cure
        • Dual cure
          • Commercial Names:
            • PanaviaEx
            • RelyX
            • ARC Resin cement

Miscellaneous Short Answers

Question 1. Temporary restorative materials.

Answer:

Temporary restorative materials:

It is restoration given to the prepared tooth for the period between tooth preparation and cementing the restoration

Features:

  • Nonirritating
  • Esthetics
  • Easy to clean
  • Maintain periodontal health
  • Adequate strength and retention

Question 2. Secondary Dentin.

Answer:

Secondary Dentin.:

  • Secondary dentin is formed after the completion of root formation
  • The direction of dentinal tubules is more asymmetrical and complicated
  • It is formed at a slower rate

Question 3. Tertiary Dentin/Reparative dentin.

Answer:

Tertiary Dentin:

  • It is formed as a response to external stimuli
  • It is irregular, with cellular inclusions
  • Its tubular pattern ranges from an irregular to a tube-lar nature
  • Reparative dentin has decreased permeability
  • It is formed by secondary odontoblasts which are differentiated from mesenchymal cells of the pulp
  • Reparative dentin helps in the prevention of diffusion of noxious agents from the tubules

Question 4. Universal Operator position.

Answer:

Universal Operator position:

  • 11 clock is considered a universal operating position

Position:

  • The dentist sits behind slightly to the right of the patient and the left arm is positioned around the patient’s head.

Advantages:

  • Most areas of the mouth are accessible from this position either using direct/indirect vision

Working Areas:

  • Palatal and incisal/occlusal surfaces of maxillary teeth
  • Mandibular teeth

Question 5. Transillumination and Magnification.

Answer:

Transillumination:

  • Used for detection of caries
  • Based on the difference in the refractory index of carious and sound normal tooth
  • Carious tooth appears as a dark shadow when compared with the normal tooth

Magnification:

  • Devices:
    • Loupes
    • Surgical telescopes
    • Bifocal eyeglasses
  • Advantages:
    • Increases visibility of the operating area
    • Easy to perform the delicate procedure
    • Increases operator’s efficiency
    • Protects eye from injury

Question 6. Soldering.

Answer:

Soldering:

  • It is the process of joining two metals together by adding the third metal
  • The soldered metal should have a melting point equal to or lower than the two metals
  • To increase the flow of solder, flux is added to it
  • However, too much of flux leads to the flowing away of solder
  • This is prevented by the addition of antiflux.

Question 7. Surface Hardness.

Answer:

Surface Hardness:

  • It is the property that is used to predict the wear resistance of a material and its ability to abrade opposing dental structures
  • Various hardness tests are used to determine the hardness of different dental materials
  • They are
    • Brinell hardness test
    • Rockwell hardness test
    • Knoop hardness test

Question 8. Modulus of elasticity

Answer:

Modulus of elasticity:

Definition:

  • It is the relative stiffness or rigidity of material within the elastic range

Measurement:

  • It is the ratio of stress to strain and is described as E

Importance

  • It indicates that the less the strain, the greater will be the stiffness
  • Elastic modulus has a constant value
  • It is not affected by the amount of plastic and elastic stress that is induced in the material
  • It is independent of the ductility of the material
  • The modulus of elasticity of enamel and dentin describes that
  • Enamel is stiffer and more brittle
  • Dentin is more flexible and tougher

Unit

  • Giganewtons per square meter (GN/ m2)
  • 2326 gauge needle is used to aspirate the contents of the lesion.

Question 9. Objectives of interim restorations.

Answer:

Objectives of interim restorations:

  • Interim restorations are often required before the placement of a permanent restoration
  • They are excepted to last for only a short period
  • Zinc oxide eugenol is the cement of choice for it

Objectives:

  • Arrests caries process
  • Protects the teeth till they get permanently restored
  • Allows pulp to heal

Question 10. Zsigmondy Palmer system

Answer:

Zsigmondy Palmer system:

  • It was introduced by Adolph Zsigmondy of Vienna in 1861 for permanent dentition and modified for primary dentition in 1874.

For permanent dentition:

  • As per this system, the oral cavity is divided into four quadrants and each permanent tooth has a specific number.
  • Numbering progresses posteriorly from the midline.
  • The central incisor was designated as 1 ending up with 8 for the third molar.

Miscellaneous For permanent dentition

For primary dentition:

  • The deciduous central incisors are designated A and progress posteriorly up to the 2nd deciduous molar alphabetically designated as E.

Miscellaneous For primary dentition

Composite Restoration Question And Answers

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Composite Restoration Important Notes

1. Disadvantages

  • Gap formation due to polymerization shrinkage, microleakage
  • Recurrent caries
  • Time-consuming
  • Technique sensitive
  • Exhibit greater occlusal wear

2. Indications

  • Class 1, 2, 3, 4, 5, and 6 restorations
  • Sealants and preventive resin restorations
  • Foundations or core build-ups
  • Luting agent
  • Temporary restoration
  • Esthetic procedures
    • Partial veneers
    • Tooth contour modification
    • Full veneer
    • Diastema closures
    • Periodontal splinting

3. Contraindications

  • When isolation is not possible
  • If all the occlusal forces will be on restorations
  • Restorations that extend on the root surface
  • Heavy occlusal stresses

4. Curing lights used for composites

  • Halogen bulb combined with filter
  • Blue light emitting device
  • Laser curing

5. Causes of failures of composites

  • Incomplete caries removal
  • Incomplete etching
  • Defective application of bonding agent

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

  • Contamination of composite
  • Improper polymerization
  • Incomplete finishing and polishing

Composite Restoration Long Essays

Question 1. Define composite. Classify and write its com¬position. Describe the management of media angular fracture of upper central right incisor not involving the pulp of patient aged 14 years.
Or
Mention indications and contraindications of composite resin. Describe the procedure of restoring a fractured incisal angle in the maxillary incisor tooth.
Or
Classify composite resins. Discuss the composi¬tion and methods to reduce the polymerization shrinkage

Answer:

Definition Of Composite:

  • It is a compound composed of at least two different materials with properties which are superior or intermediate to those of an individual component.

Classification:

1. According to the particle size:

  • Traditional composite – 8-12 pm
  • Small-sized composite – 1-5 pm
  • Microfilled composite – 0.4-0.9pm
  • Hybrid composite – 0.6-1 pm

2. According to filler particles:

  • Megafilled
  • Macrofilled
  • Midfilled
  • Minifilled
  • Microfilled
  • Nanofilled

3. According to the polymerization method:

  • Self-curing
  • Ultraviolet light curing
  • Visible light curing
  • Dual curing

Composition:

  • Organic resins – BisGMA/UDMA
  • Fillers – Zinc, Silicates, Aluminium, Zirconium
  • Coupling agent – Organic silane
  • Coloring agents – Titanium oxide
  • Initiator – Camphor quinone
  • Inhibitor – Butylated hydroxyl toluene

Indications

  • Restoration of Class 1, 2, 3, 4, 5, 6
  • Discolored tooth
  • Midline diastema cases
  • Veneers and laminates
  • Bonding of orthodontic appliances
  • Restoration of the non-carious lesions
  • Core foundation
  • As indirect restoration
  • For periodontal splinting

Contraindication:

  • Difficult to isolate the area
  • Patient with high caries index and poor oral hygiene
  • Extensive caries, sub-gingivally
  • Lesions over the distal surface of the canine

Composite Restoration

Methods To Reduce Polymerization Shrinkage

1. By the addition of fillers

  • Hybrid composites shrink- 0.6-1.4%
  • Microfilled composites shrink – 2-3%

2. Incremental placement of composites

  • Shrinkage is allowed after the placement of increment before the next increment placement
  • This controls polymerization shrinkage

Restoration Of Fractured Central Incisor:

Anesthetized and isolated the tooth
↓
Selection of proper composites
↓
Shade selection – Done in natural daylight Dentin shade selected from
cervical 3rd Enamel shade selected from incisal 3rd
↓
Tooth preparation

1. Enamel margins at 90°

2. Butt joint on root surfaces

3. Enamel bevel

4. Roughening of tooth surfaces

↓
Bonding – Etching, priming and bonding with bonding
agents
↓
Composite placement – In increments along with curing
↓
Carving

1. Attain proximal contour

2. Remove excess material

↓

1. Finishing with diamond points

2. Polishing with rubber points, abrasive discs

Composite Restoration Conventional tooth preparation for composite restoration

Composite Restoration Beveled preparation for composite restoration

Composite Restoration Horizontal technique

Question 2. Enumerate various uses of composite. Describe the restoration of class 2 cavity preparation.
Or
Composite as a posterior restorative material.

Answer:

Various uses of composite:

Indications:

  • Small, incipient lesions
  • Possible to control moisture
  • As core foundation
  • Patient with low caries index

Contra-Indications:

  • Difficult to control moisture
  • Extensive lesion
  • High occlusal stresses
  • Presence of parafunctional habits
  • Patients with high caries index and poor oral hygiene

Disadvantages:

  • Polymerization shrinkage
  • Technique sensitive
  • Time-consuming
  • Expensive compared to amalgam

Composite Restoration

1. Tooth preparation

  • Use small round bur, initially
  • Extend preparation using fissure bur
  • Maintain minimal depth
  • Faciolingual dimension l/4th of intercuspal dis¬tance
  • No need of retentive features
  • Converging occlusal walls
  • Rounded line angles
  • Bevelling of enamel margin

Composite Restoration Types conventional class 1 tooth preparation for composite restoration

  1. (A) Preparation of outline usinground bur
  2. (B) Excavation of caries, keeping the pulpal floor shallow
  3. (C) Completed class I tooth preparation

2. Matrix placement in Class 2

3. Etching the preparation with 37% phosphoric acid

4. Application of primer and adhesive

5. Pulp protection

  • Use of calcium hydroxide as base
  • GIC as liner

6. Composite Placement

  • In increments and subsequently curing it

7. Finishing and Polishing
Composite Restoration Composite should be placed in small increments so as to reduce polymerization shrinkage

Composite Restoration Short Essays

Question 1. Methods of curing composites.

Answer:

Methods of curing composites:

1. Tungsten quartz Halogen curing unit

  • It is conventional
  • Uses visible light in the range of 410-500 nm
  • Limited lifetime of 100 hours
  • Starts curing cycle at a low power density
  • Time-consuming
  • Plasma arc curing unit
  • Use of high-frequency electrical field
  • This field ionizes xenon gas into a mixture of ions, electrons, and molecules
  • Results in the release of energy in the form of plasma
  • Uses 450-500 nm wavelength
  • Expensive

2. Light-emitting diode unit

  • Have long life i.e. approximately 10,000 hours
  • A wavelength of 400-500nm is used
  • Suitable for composite with camphor-quinone photoinitiator

3. Argon Laser curing unit

  • Uses a wavelength of 470 nm
  • Monochromatic in nature
  • Produces intensity of 200-300 mW
  • May cause pulpal damage
  • Has a higher degree of polymerization

Question 2. Visible Cured Composite.

Answer:

Visible Cured Composite:

Wavelength – 460-470 nm

Mechanism:

On activation, photoinitiator combines with amine accel-
orator
↓
Release of free radicles
↓
Polymerization

Advantage: Improved color stability

Photoinitiator Used: Camphoroquinone

Composite Restoration Short Answers

Question 1. Packable composite.

Answer:

Packable composite:

  • The basis is Polymer Rigid Inorganic Matrix Material (PRIMM)
  • Components – Resin and ceramic inorganic fillers in-corporates in a silanated network of ceramic fibers
  • Filler content – 48-65% by volume
  • Particle size – 0.7-20 pm

Indications:

  • Stress bearing areas
  • Class 2 restoration

Advantages:

  • Increased wear resistance
  • Better reproduction of occlusal anatomy
  • The deeper depth of cure
  • High flexural modulus
  • Decreased polymerization shrinkage

Question 2. Failure in Composite Restoration.

Answer:

Failure in Composite Restoration:

Causes:

  • Incomplete caries removal
  • Incomplete etching
  • Defective application of bonding agent
  • Contamination of composite
  • Improper polymerization
  • Incomplete finishing and polishing

Failures Seen:

  • Discoloration
  • Marginal fracture
  • Secondary caries
  • Restoration fracture
  • Post-operative sensitivity
  • Plaque accumulation

Question 3. Fillers in Composites.

Answer:

Commonly Used Fillers:

  • Silica, aluminium, zinc, barium, zirconium
  • Boron silicate

Effects:

  • Reduces thermal expansion
  • Reduces polymerization shrinkage
  • Reduces water sorption
  • Increases abrasion resistance
  • Increases strength
  • Improves handling properties
  • Increases translucency

Question 4. Microfilled Composite.

Answer:

Microfilled Composite:

  • Particle size – 0.04 – 0.1 micrometer
  • Filler content-35-50% by weight

Properties:

  • Low modulus of elasticity
  • Excellent translucency
  • Low fracture toughness
  • Marginal breakdown

Indication:

  • Anterior teeth restoration
  • Cervical abfraction lesions

Question 5. Hybrid Composite.

Answer:

Hybrid Composite:

  • Made up of polymer groups reinforced by an inorganic phase
    • Particle size – < 2 nm
    • Filler content- 75-80% by volume

Generations               Particle size (pm)

Nanofill             –            0.04-0.1

Nanohybrid       –           1-3

Microhybrid       –          0.4-0.8

Indications:

  • Posterior restoration
  • Class 3, 4, and 5 restoration
  • Direct veneer
  • Discoloration of teeth

Question 6. Light Cured Composite.

Answer:

Light Cured Composite:

  • Polymerization is towards the light source
  • Material is placed in increments

Advantages:

  • Adequate working time
  • Good color stability
  • Aesthetically good
  • Less polymerization shrinkage
  • More abrasion resistance

Activator Used:

  • Ultraviolet – 0.1% Benzoin methyl ether
  • Visible light-Camphoroquinone

Question 7. Coupling agents.

Answer:

Coupling agents:

  • The coupling agent bonds the filler particles to the resin matrix
  • The most commonly used coupling agent are organosilanes
  • In the presence of water, the methoxy group of it forms an ionic bond with the filler particle
  • On the other end, methacrylate group forms a covalent bond with resin when it is polymerized

Functions:

  • Transfers stress to filler particles
  • Improves physical and mechanical properties
  • Inhibits leaching by preventing water from penetrating along the filler resin interface

Question 8. Nanocomposite restoration.

Answer:

Nanocomposite restoration:

  • Nanocomposites contain filler particles that are extremely small [0.005-0.01 micrometer]
  • They may be clustered or aggregated into large units that can be blended with nanoparticles to produce nanohybrids

Advantages:

  • Good physical properties
  • Improved esthetics
  • Small particle size
  • Highly polishable

Question 9. Resin matrix in restorative resin

Answer:

Resin matrix in restorative resin:

  • Matrix of composite resin consists of BisGMA, urethane methacrylate or TEGDMA
  • Bis-GMA is a difunctional monomer produced as the reaction product of bisphenol*A and glycidyl methacrylate

Functions

  • Reduces polymerization shrinkage
  • Increases strength and rigidity
  • Increases viscosity

Composite Restoration Viva Voce

  1. The color matching for composites when done in a dry state would make the tooth appear lighter than the adjacent teeth
  2. BIS-GMA and UDMA are extremely viscous
  3. Conventional composites have a higher amount of ini¬tial wear at occlusal contacts
  4. Microfill composites are used for restoring class 5 cervical lesions
  5. Flowable composites should never be placed in areas of occlusal stress
  6. Higher filler contents exhibit lower water sorption
  7. Material with higher modulus is more rigid
  8. Natural light should be used for the selection of shades of composites
  9. Dentin gingival margin is more prone to marginal microleakage
  10. Composite should be protected from light to prevent premature polymerization
  11. Acid-etched enamel surface has a frosted appearance

Minimal Intervention Dentistry Question And Answers

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Minimal Intervention Dentistry Short Essays

Question 1. Minimum Intervention dentistry.

Answer:

Minimum Intervention dentistry:

  • It is defined as a philosophy of professional care which deals with the first occurrence, earliest detection, and earliest cure of the disease on micro levels, followed by minimally invasive treatment to repair irreversible dosage caused by that disease

Dental Materials Used:

  • GIC
  • Resin-based composites
  • Dentin bonding agents
  • Combination of composites and GIC

Treatment Options:

  • ART
  • Sandwich technique
  • Chemomechanical caries removal
  • Tunnel preparation

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  • Pit and fissure sealant
  • Box and slot preparation
  • Tooth preparation using laser

Minimal Intervention Dentistry The ART technique of tooth restoration

  1. (A) Carious lesion in posterior tooth
  2. (B) Excavation of caries using hand instruments
  3. (C) Restoration of the tooth using glass ionomer cement

Minimal Intervention Dentistry Tunnel preparation

Minimal Intervention Dentistry Box and slotpreparation. These involve the margin ridges but not the occlusial pits and fissures

Minimal Intervention Dentistry

Dentinal Hypersensitivity Question And Answers

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Dentinal Hypersensitivity Long Essays

Question 1. Management of dentin hypersensitivity

Answer:

Management of dentin hypersensitivity:

1. Home care with dentrifices

  • 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

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

Dentinal Hypersensitivity Theories of dentin hypersensitivity

  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.

Dentinal Hypersensitivity

Non Carious Lesions And Management Question And Answers

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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

Materials Used For Its Restoration:

  • GIC
  • Composite
  • Silver Amalgam

Abfraction:

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

Non Carious Lesion Abfraction lesions may appear as minor cracks in early stages but in later stages they appear as grooves extending into dentin

Etiology: Occlusal loading on the tooth

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

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: It is the loss of tooth substance caused by a chemical process that does not involve known bacterial action.
  2. Abrasion: It 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:

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

Causes:

1. Intrinsic:

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

2. Extrinsic:

  • Dietary origin
  • Occupational
  • Drug-induced – Aspirin

Features:

  • Broad saucer-shaped depression
  • Surface – smooth, hard, and polished

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  • Sensitive tooth
  • Site – Gingival third of the labial surface of anterior

Question 3. Abrasion.

Answer:

Abrasion:

Definition:

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

Causes:

  • Faulty oral hygiene practice
  • Abnormal oral habits

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

Dental Veneer Question And Answers

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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

  • Types

Veneers Incisal preparation types

Veneers Short Essays

Question 1. Veneers.

Answer:

Veneers:

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

Indications:

  • Defective surface
  • Discolored facial surface
  • Discolored restoration

Types:

1. Based on the method of fabrication:

  • Direct technique
  • Indirect technique

2. Based on the extent of coverage:

  • Partial veneer
  • Full veneer

Procedure:

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

Veneers Direct partial veneer involving only localized surface of labial part of the tooth

Veneers Short Answers

Question 1. Incisal Lapping for Veneers.

Answer:

Incisal Lapping for Veneers:

Indications:

  • Crown lengthening
  • Severe incisal defect

Advantages:

  • No need for temporary restoration

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  • Improved esthetics

Veneers Full veneer with incisal lapping preparation

Question 2. Direct Veneer.

Answer:

Direct Veneer:

Indications:

  • Localized discoloration

Advantages:

  • Single appointment
  • Economical

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.

Dental Veneer

Dental Bonding Question And Answers

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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

  • It is used to bond
    • Amalgam to tooth
    • Amalgam to amalgam
    • Amalgam to other metal substrates

5. Dentin bonding agents – generations

Bonding Dentin bonding agents - generations

6. Bond strength of various bonding systems

Bonding Bond strength of various bonding system

Bonding Short Essays

Question 1. Acid etching.

Answer:

Acid etching:

  • It 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.

Mechanism:

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

Bonding Formation of microtags and macrotags when bonding agent is appiled to etched tooth surface

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

Technique:

  • Oral prophylaxis
  • Isolate the tooth
  • Application of etchant for 15 seconds
  • Rinse thoroughly for 5-10 seconds

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  • 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 Dentin Bonding agents

Bonding Fourth generation bonding system is available in two bottles, one primer and other adhesive resin

Bonding While in fifth generation bonding agents, primer and adhesive are combined in one bottle only

Bonding Short Answers

Question 1. Hybridization.

Answer:

Hybridization:

  • Given by Nakabayachi
  • It 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.

Dental Bonding

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:

  • It 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

Bonding Smear layer and smear plugs

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

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