5 Composite Restoration and Polymerization Overview
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Questions and Answers

What should be avoided when cleaning the operating site prior to a composite restoration?

  • Acid-etch solutions
  • Water-based cleansing agents
  • Cotton rolls
  • Prophy pastes with flavoring agents (correct)

Which is NOT a contraindication for using direct composite restorations?

  • Gap formation at the composite and root junction
  • All occlusion on the restorative material
  • Inability to isolate the operating site
  • Composite restoration extensions on the enamel (correct)

At what point should shade selection for composite restorations occur?

  • After the bonding process
  • During the finishing and polishing phase
  • Before prolonged drying of teeth (correct)
  • Immediately after local anesthesia administration

Which attribute of color indicates how rich or vivid a color appears?

<p>Chroma (A)</p> Signup and view all the answers

What is the effect of using poor lighting during shade selection?

<p>It may cause color misjudgment (A)</p> Signup and view all the answers

Which procedure contributes to a more comfortable composite restoration experience?

<p>Using local anesthesia (C)</p> Signup and view all the answers

What can be a result of dehydrating teeth prior to shade selection?

<p>Teeth may lose their translucency (B)</p> Signup and view all the answers

What procedure should be performed two weeks prior to placing restorations if bleaching is contemplated?

<p>Bleaching of teeth (C)</p> Signup and view all the answers

What is the C-factor of a Class I restoration?

<p>5 (D)</p> Signup and view all the answers

Which technique can help reduce internal stresses in restorations with a high C-factor?

<p>Oblique incremental additions (A)</p> Signup and view all the answers

What is a disadvantage of composite restorations compared to amalgam?

<p>Greater occlusal wear under stress (C)</p> Signup and view all the answers

What is one of the advantages of composite restorations?

<p>They are repairable (B)</p> Signup and view all the answers

In which scenario would a filled dentinal adhesive be particularly useful?

<p>As a stress-breaking liner (C)</p> Signup and view all the answers

Which of the following restorations can composites be used for?

<p>All Class restorations (I, II, III, IV, V, VI) (C)</p> Signup and view all the answers

What is a factor that can lead to gap formation in composite restorations?

<p>Forces of polymerization shrinkage exceeding adhesive bond strength (A)</p> Signup and view all the answers

Which characteristic of composites contributes to their use as an aesthetic material?

<p>Translucency and color matching (C)</p> Signup and view all the answers

What is the primary function of diketone initiators in the curing process of composites?

<p>To initiate the polymerization reaction upon irradiation (B)</p> Signup and view all the answers

Which method of polymerization creates high-intensity curing and is known for speed?

<p>Plasma arc curing systems (C)</p> Signup and view all the answers

What effect does polymerization shrinkage have on composite restorations?

<p>May create gaps at the tooth restoration interface (A)</p> Signup and view all the answers

How can polymerization shrinkage be controlled during the composite application?

<p>By adjusting the adhesive used (D)</p> Signup and view all the answers

What is the C-factor in the context of composite restorations?

<p>The ratio of bonded surfaces to free surfaces in a tooth preparation (B)</p> Signup and view all the answers

Which curing system is noted to decrease in efficiency over time?

<p>Quartz, tungsten halogen light-curing systems (A)</p> Signup and view all the answers

What occurs upon irradiation of diketone initiators during the curing process?

<p>They dissociate into radicals (D)</p> Signup and view all the answers

What is a disadvantage of using plasma arc curing systems?

<p>Increased heat generation and polymerization shrinkage (B)</p> Signup and view all the answers

What lighting conditions are recommended for accurate shade selection in the absence of natural daylight?

<p>Color corrected operating lights or ceiling lights (B)</p> Signup and view all the answers

Why should the dental operating light be moved away during shade selection?

<p>To decrease the light intensity and observe shadows (A)</p> Signup and view all the answers

Which feature distinguishes enamel shades from dentin shades in composite materials?

<p>Enamel shades are more translucent. (B)</p> Signup and view all the answers

What is the primary purpose of using a shade guide during dental procedures?

<p>To select appropriate materials for dental restorations (D)</p> Signup and view all the answers

How long should shade selection be attempted before eye fatigue makes it difficult to distinguish colors?

<p>30 seconds (A)</p> Signup and view all the answers

What technique can be used to rest the eyes after prolonged shade selection?

<p>Look at a blue or violet object (B)</p> Signup and view all the answers

What is the role of placing a small amount of material of the selected shade on the tooth?

<p>To assess the accuracy of the selected shade (C)</p> Signup and view all the answers

What is a common mistake when using shade guides from different manufacturers?

<p>Shade guides may not accurately reflect colors across manufacturers. (B)</p> Signup and view all the answers

Flashcards

Composite Polymerization

A chemical reaction changing low-molecular-weight monomers into high-molecular-weight polymer chains.

Light-Curing

Polymerization process activated by visible light, typically using a blue LED light.

Polymerization Shrinkage

Volume change during composite polymerization, potentially creating gaps at interfaces.

Debonding

Separation of the composite from the tooth due to polymerization shrinkage exceeding the bond's strength.

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C-factor

Ratio of bonded surfaces to unbonded surfaces in a tooth preparation, indicating bond disruption risk.

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Increment Thickness

The amount of composite added at a time during restoration.

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Composite Restoration

Dental filling using composite materials.

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Photo-initiator

A chemical that initiates a polymerization reaction when exposed to specific wavelengths of light.

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Operating Light Intensity

Adjusting dental operating lights to reduce intensity for better shade selection.

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Shade Guide

A guide used to match the color of dental materials to the tooth.

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Shade Guide Interchangeability

Different manufacturers' shade guides are not typically interchangeable.

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Vita Classical Shade Guide

A universally used shade guide for cross-referencing.

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Composite Translucence

Composite materials come in translucent (for visible areas) and opaque (for coverings) versions.

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Shade Selection Technique

Quickly select shade using the guide to avoid eye fatigue by looking at blue/violet objects if needed.

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Shade Confirmation

Place a small amount of material on the tooth for a final shade check.

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Essential Shades

Common shades used for restorations categorized by frequency of use.

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Composite Restoration Contraindications

Conditions where a direct composite resin restoration is not suitable, such as when occlusal forces are solely on the restoration or the restoration needs to extend onto the root.

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Shade Selection Timing

Dental shade selection should occur before extended drying to avoid shade change due to dehydration, and ideally before any prior bleaching.

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Optimal Lighting for Shade Selection

Natural light is preferred for accurate shade selection of teeth.

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Ideal Pre-Restorative Bleaching

Bleaching should be completed two weeks prior to a restoration to avoid inaccurate shade matching due to the bleaching effect.

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Operating Site Preparation

Cleaning the operative site before any composite restoration to remove plaque, stains, and calculus promoting bonding.

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Anesthesia's Role in Restorations

Local anesthesia enhances patient comfort, procedure flow, and reduces saliva production during restorative procedures.

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Tooth Value and Vitality

Teeth with high value/brightness appear more vital and alive; low value/brightness teeth appear grey and less vital.

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Prophy paste precautions

Flavoring agents, glycerin or fluorides in prophy pastes can interfere with acid-etch techniques.

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Class IV Restoration Risk

A Class IV restoration (one bonded surface, four unbonded surfaces) with a C-factor of 0.25 is at low risk for adverse polymerization shrinkage.

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Class I Restoration Risk

A Class I restoration (five bonded surfaces, one unbonded surface) with a C-factor of 5 is at high risk for bond disruption due to polymerization shrinkage, especially on the pulpal floor.

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Reducing Internal Stresses

Use oblique incremental additions and stress-breaking liners (like filled dentinal adhesive, flowable composite, or RMGI) to minimize polymerization shrinkage in high-risk restorations (like Class I).

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Composite Restoration Advantages

Composite restorations offer good retention, low microleakage, minimal staining, increased tooth strength, esthetics, and conservative tooth removal compared to amalgam.

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Composite Restoration Disadvantages

Composite restorations can have gap formation (especially on root surfaces) due to polymerization shrinkage exceeding initial bond strength or improper insertion. They are more technique-sensitive and prone to occlusal wear under high stress.

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Composite Restoration Technique Sensitivity

Proper isolation and bonding techniques are critical to avoid gaps and ensure success with composite restorations.

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C-Factor Definition

The C-factor is a measurement of the number of bonded and unbonded surfaces in a cavity preparation. It helps determine the risk of polymerization shrinkage.

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Indications for Composite Restorations

Composite restorations are used for various types of cavities, foundation building, and core buildups.

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Study Notes

Composite Restoration (2)

  • Composite restorations are superior to amalgam restorations in terms of aesthetics, minimal depth of tooth removal, and high resistance
  • Composite restorations bond to tooth structure, thus decreasing microleakage, providing high retention and minimal interfacial staining
  • Composite restorations are esthetic and versatile, and their use is universal
  • Composite restorations are repairable
  • Composite restorations have a low thermal conductivity, acting as an insulator

Polymerization

  • Polymerization is a chemical reaction where low molecular weight monomers are converted into high molecular weight polymers
  • Two methods of polymerization are self-cured and light-cured, utilizing visible light
  • Diketone initiators, such as camphoroquinone, are activated by wavelengths between 370-500 nm with a peak at 468 nm, initiating a radical chain reaction of monomer polymerization

Curing Devices

  • Quartz, tungsten halogen light-curing systems decrease efficiency over time
  • Plasma arc curing systems are high-intensity, high-speed curing systems, but they generate significant stresses due to heat generation and polymerization shrinkage
  • LED light-curing units are more efficient, portable, and durable

Polymerization Shrinkage

  • Composite materials shrink during polymerization, leading to polymerization shrinkage
  • Shrinkage can cause gaps at the tooth restoration interface if not controlled
  • Controlling polymerization shrinkage is done by:
    • Using appropriate adhesives
    • Adjusting the amount of composite used (increment thickness)
    • Using proper increment configuration
  • High C-factor restorations (high ratio of bonded surfaces to unbonded) are more prone to polymerization shrinkage

C-Factor

  • C-factor is the ratio of bonded to unbonded surfaces in a tooth preparation
  • Higher C-factor indicates a greater risk of bond disruption from polymerization shrinkage
  • Class IV restorations (one bonded surface, four unbonded) have a low risk of shrinkage, while Class I restorations (five bonded surfaces, one unbonded) have a high risk

Internal Stresses

  • Internal stresses from polymerization shrinkage can be reduced by using oblique incremental additions or stress-breaking liners (such as filled dentinal adhesive, flowable composite, or RMGI)

Advantages/Disadvantages

  • Advantages*

  • High retention and strength

  • Low microleakage

  • Minimal interfacial staining

  • Esthetic properties

  • Effective thermal insulation

  • Repairable

  • Disadvantages*

  • Potential for a gap formation, especially on root surfaces, due to polymerization shrinkage forces exceeding the initial bond strength to the dentin

  • Technique sensitivity compared to amalgam restorations (more difficult, time-consuming, and costlier) for gap formation to occur

  • Operative site must be properly isolated and bonded, and bonding technique is crucial and essential

  • Increased potential for occlusal wear in areas of high stress during stress or contacts

Indications/Contraindications

  • Indications*

  • Direct restorations (Classes I-VI)

  • Foundations or core buildups

  • Sealants and preventive resin restorations

  • Esthetic enhancement procedures (partial veneers, full veneers, tooth contour modifications, diastema closures)

  • Periodontal splinting

  • Contraindications*

  • Oral contamination and fluids can prohibit isolation or bonding

  • If occlusion entirely affects the restorative material, other materials may be necessary to prevent gap formation.

  • Composite restorations exceeding the root surfaces may result in gap formation

  • Composite restorations are not appropriate for locations prone to high stress

Clinical Technique

  • Local anesthesia to create comfort, interrupted procedure, and reducing salivation
  • Preparation of operative site, including removing plaque, pellicle, stains, and calculus
  • Shade selection, particularly before prolonged drying as teeth dehydrate, decrease in translucency, and become lighter in shade
  • Pre-operative occlusion assessment using articulating paper
  • Isolation using rubber dam or cotton rolls to prevent contamination
  • Bonding, incremental packing, and finishing and polishing step-by-step technique

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Lecture 5 Composite Restoration Part (2) PDF

Description

This quiz explores the techniques and benefits of composite restorations in dentistry, highlighting their aesthetic advantages and bonding properties. Additionally, it covers the process of polymerization, including methods and curing devices used in dental applications. Test your understanding of these important concepts in restorative dentistry.

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