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

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