Operative Dentistry: Composite Restoration

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Questions and Answers

What is the primary reason for holding the shade guide near the tooth during the shade selection process?

To match the color of the teeth accurately

To reduce the time taken for selection

To improve visibility in low light

To minimize eye fatigue due to color receptors (correct)

Which type of shade should be used in areas requiring translucency, such as incisal edges?

Enamel shade (correct)

Opaque shade

Body shade

Dentin shade

What method can be used to confirm the selected shade before restoration?

Assessing external lighting conditions

Placing a small amount of material on the tooth (correct)

Visual comparison with a shade guide

Using a digital shade matcher

What is a consequence of not isolating the operative field during tooth-colored restorations?

Decreased bond strength to etched enamel Signup and view all the answers

Which of the following shades is considered common in the essential shades selection?

Common Signup and view all the answers

What color should the operator look at to enhance their ability to perceive color after prolonged shade selection?

Blue or violet Signup and view all the answers

Which term refers to shades that are characterized by a lack of hue and greater opacity?

Opaque shade Signup and view all the answers

Why is it essential to identify the pre-operative occlusal contacts before restoration?

To correctly plan the restoration outline and occlusal contacts Signup and view all the answers

What is the primary benefit of achieving profound anesthesia during a procedure?

Creates a more comfortable experience for the patient Signup and view all the answers

Which of the following should be avoided during the preparation of the operating site?

Fluoride-containing prophy pastes Signup and view all the answers

When should the shade of the tooth ideally be selected?

Before the teeth are subjected to prolonged drying Signup and view all the answers

Which lighting condition is most effective for shade selection?

Natural light Signup and view all the answers

What should be the first step in the clinical technique for composite restoration?

Preparation of the operating site Signup and view all the answers

Which of the following is a reason for using incremental packing in composite restoration?

To reduce the risk of air bubble formation Signup and view all the answers

Why is it essential to confirm shade selection before bleaching procedures?

It ensures the restoration matches post-bleaching color Signup and view all the answers

Which type of shade guides are commonly used in dental restorations?

Shade guides specific to manufacturers' materials Signup and view all the answers

Which method of curing composites involves a chemical reaction initiated by a diketone initiator?

Light-cured method Signup and view all the answers

What is the primary reason for polymerization shrinkage in composite materials?

Low molecular weight monomer conversion to high molecular weight polymer Signup and view all the answers

Which variable significantly affects the bond strength of composite material during polymerization?

Increment thickness Signup and view all the answers

What does C-factor refer to in the context of composite restorations?

Ratio of bonded to unbonded surfaces Signup and view all the answers

Which of the following light sources is noted for its efficiency and portability in curing composites?

Light-emitting diodes (LEDs) Signup and view all the answers

In the context of composite restorations, what is an advantage of using a plasma arc curing system?

High-intensity and high-speed curing Signup and view all the answers

Which of the following is NOT a method to control polymerization shrinkage?

Increasing the composite shade variety Signup and view all the answers

What factor is identified as a low risk for adverse polymerization shrinkage effects in a Class IV restoration?

Both B and C Signup and view all the answers

Study Notes

Composite Restoration (2)

Batterjee Medical College, operative dentistry division presentation
Key learning objectives focus on advantages/disadvantages, indications/contraindications, and clinical techniques
Reference: Art and science of operative dentistry 6th edition, chapter 8, page 216

Polymerization

Chemical reaction converting low molecular weight monomer molecules to high molecular weight polymer chains
Two methods exist: self-cured and light-cured (using visible light)

Light Curing

Diketone initiators (e.g., camphoroquinone) are activated by wavelengths in the 370-500nm range, peaking at 468nm (blue region of the visible spectrum)
Upon irradiation, initiators dissociate into radicals

Curing Devices

Quartz, tungsten halogen light-curing systems efficiency decreases with time
Plasma arc curing systems offer high intensity and speed, but also significantly increase stresses from heat generation and polymerization shrinkage
Light-emitting diodes (LEDs) are the predominant curing method today, due to their increased efficiency, portability, and durability

Polymerization Shrinkage

Composite materials shrink during polymerization (volume change)
This shrinkage can lead to gaps at the tooth restoration interface if the bond strength is insufficient
Controlling shrinkage involves proper adhesive use, increment thickness, and increment configuration during insertion

C-factor

Ratio of bonded surfaces to unbonded surfaces in a tooth preparation
The higher the C-factor, the greater the potential for bond disruption from polymerization shrinkage
Class IV restorations (one bonded surface, four unbonded) have a lower C-factor (low risk), while Class I restorations (five bonded surfaces, one unbonded) have a higher C-factor (higher risk)

Reducing Internal Stresses

Use oblique incremental additions to reduce polymerization shrinkage effects
Employ stress-breaking liners (e.g., filled dentinal adhesives, flowable composites, or RMGI)

Advantages of Composite Restorations

Bonded to tooth structure, leading to good retention, low microleakage, and minimal staining.
Increased strength of remaining tooth structure
Esthetic restorations
Conservative in tooth preparation
Insulating due to low thermal conductivity
Widely used and readily repairable

Disadvantages of Composite Restorations

Gap formation, often on root surfaces, possibly due to the forces of polymerization shrinkage, or improper insertion
More technique-sensitive and complex requiring appropriate isolation and bonding technique
Can exhibit greater occlusal wear in areas of high occlusal stress or if all occlusal contacts are on the restoration

Indications for Composite Restorations

Direct restorations (Classes I, II, III, IV, V, and VI)
Foundations or core buildups
Sealants and preventive resin restorations (PRR)
Esthetic procedures (full and partial veneers, contour modifications, diastema closures)
Periodontal splinting

Contraindications for Composite Restorations

If the operating site cannot be isolated from oral fluids
If all occlusal contacts are on the restoration
Composite restoration extensions on root surfaces may exhibit gap formation

Clinical Technique

Local Anesthesia
Operating site preparation
Shade selection & confirmation
Pre-operative occlusion assessment
Isolation
Bonding
Incremental packing
Finishing & polishing

Shade Selection

Shade selection should be performed before prolonged drying to avoid dehydration-related shade changes
Bleaching, if performed, should be completed before restorations
Employ proper lighting (natural light preferred) and color corrected operating lights
Use a shade guide, and confirm selection by placing a small amount of the material directly onto the tooth

Shade Guide

Most manufacturers provide shade guides for their materials which may not be interchangeable
Manufacturers often cross-reference their shades with the Vita Classical shade guide, a widely used standard

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Description

This quiz focuses on the key concepts of composite restoration in operative dentistry, particularly the advantages, disadvantages, and clinical techniques. It includes insights from the 'Art and Science of Operative Dentistry' 6th edition. Knowledge of polymerization and light curing methods will also be assessed.