Operative Dentistry Chapter 8 Quiz

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Questions and Answers

What is the primary reason RMGI restoration is recommended over composite restoration on the root surface?

It is less expensive than composites.

It is faster to apply than composites.

It can withstand higher occlusal forces.

It minimizes gap formation at the junction. (correct)

Which step is essential to improve bonding during composite restoration preparation?

Cleaning the operating site to remove contaminants. (correct)

Performing shade selection before cleaning.

Applying fluoride before restoration.

Using a prophy paste with flavoring agents.

Why is shade selection performed before prolonged drying of teeth?

Because lighting conditions do not affect color.

To enable dentists to use inaccurate shade guides.

To avoid damage from excessive moisture.

Because dehydrated teeth appear lighter in shade. (correct)

What type of lighting is ideal for shade selection in composite restorations?

Natural sunlight. Signup and view all the answers

What effect does proper local anesthesia have during the composite restoration procedure?

Allows for a more comfortable and uninterrupted procedure. Signup and view all the answers

What is a potential issue with using prophy pastes containing glycerin during preparation?

They can leave a residue that interferes with bonding. Signup and view all the answers

Which statement about shade guides is correct?

Manufacturers typically cross-reference their shades with the Vita Classical shade guide. Signup and view all the answers

What is the effect of using shade guides from different manufacturers?

They can cause mismatches in shade selection. Signup and view all the answers

What type of polymerization method is activated using visible light within a specific wavelength range?

Light-cured method Signup and view all the answers

Which light-curing system provides high-intensity and high-speed curing but may increase stresses from heat generation?

Plasma arc curing systems Signup and view all the answers

What is the significance of the C-factor in tooth preparation during composite restoration?

Represents the ratio of bonded to unbonded surfaces Signup and view all the answers

What is the primary effect of polymerization shrinkage during composite curing?

Pulls the material away from the preparation walls Signup and view all the answers

Which factor can help control polymerization shrinkage in composite restorations?

The amount and configuration of inserted composite Signup and view all the answers

Why are blue LED light-curing units preferred in modern dentistry?

They are more efficient and portable Signup and view all the answers

What initiator is commonly used in light-cured composite systems?

Camphoroquinone Signup and view all the answers

In a Class IV restoration, what is the calculated C-factor?

0.25 Signup and view all the answers

What does chroma refer to in shade selection?

The intensity or saturation of the color Signup and view all the answers

Which shade is typically associated with enamel materials?

Translucent shades Signup and view all the answers

What is an effective technique to avoid eye fatigue during shade selection?

Use blue or violet colors to rest the eyes Signup and view all the answers

What should be done to confirm the selected shade for restoration?

Apply a small amount of material directly on the tooth Signup and view all the answers

Why is it important to assess occlusal contacts before a restoration?

To plan the restoration outline and its proper function Signup and view all the answers

Which method is NOT recommended for isolating the operative field?

Using no isolation method Signup and view all the answers

What can result from contamination of etched enamel or dentin?

Decreased bond strength Signup and view all the answers

What color should be used to rest the eyes if shade selection takes too long?

Blue Signup and view all the answers

What is the main characteristic of a Class I restoration with a C-factor of 5?

It has a higher risk of bond disruption. Signup and view all the answers

Which of the following methods can help reduce internal stresses in Class I restorations with a high C-factor?

Oblique incremental additions. Signup and view all the answers

What is one significant disadvantage of composite restorations compared to amalgam restorations?

They are more technique sensitive. Signup and view all the answers

When are composite restorations considered contraindicated?

When the operating site cannot be isolated from contamination. Signup and view all the answers

Which of these is an advantage of composite restorations?

They exhibit low thermal conductivity. Signup and view all the answers

What could lead to gap formation in composite restorations?

Early bond strength failure during placement. Signup and view all the answers

Which of the following statements about composite restorations is incorrect?

They require considerable tooth structure removal. Signup and view all the answers

Which restoration types are direct indications for the use of composite materials?

Class I, II, III, IV, V, and VI restorations. Signup and view all the answers

Study Notes

Composite Restoration (2)

Batterjee Medical College, a college for Science and Technology, is the source of the presentation.
The presenter, Dr. Rehab Alwakeb from Operative Dentistry, discusses composite restorations.
Reference material is the Art and Science of Operative Dentistry 6th edition, chapter 8, page 216.
Learning Objectives (ILOs) include determining composite restoration advantages, disadvantages, indications, and contraindications.
The second ILO is determining the clinical technique for composite application.

Properties (Continuation)

Polymerization is a chemical reaction changing low molecular weight monomers into high molecular weight polymers.
The two polymerization approaches are self-cured and light-cured. Light curing utilizes visible light.

Light Curing

Camphoroquinone is a type of diketone photo-initiator activated by wavelengths between 370-500 nm, and peaking at 468 nm (blue light).
Upon irradiation, it dissociates into radicals.

Curing Devices

Quartz, tungsten halogen light curing systems decrease in efficiency over time.
Plasma arc curing systems offer high-intensity and speed compared to quartz/tungsten systems.
Heat generation and polymerization shrinkage increase stress.
Light-emitting diodes (LEDs) are the predominant approach today; they are more efficient, portable, and durable.

Polymerization Shrinkage

Composite materials shrink during polymerization (shrinkage/volume change).
This shrinking can produce gaps at the tooth restoration interface if the polymerization shrinkage force is greater than the bond strength of the composite to dentin.
Controlling polymerization shrinkage: appropriate use of adhesives, incremental composite thickness, and increment configuration.

C-factor

The C-factor is the ratio of bonded surfaces to unbonded surfaces after preparing a tooth.
A higher C-factor indicates a greater potential for disruption from polymerization shrinkage.
Class IV restorations (one bonded, four unbonded) have a low risk of shrinkage issues (C-factor of 0.25), while Class I restorations (five bonded, one unbonded) have a higher risk (C-factor of 5).

Internal Stress Reduction

High internal stress in restorations due to potentially high polymerization shrinkage (Class I preparations) can be reduced.
Two approaches: oblique incremental additions and the use of stress-breaking liners (filled dentin adhesive, flowable composite, RMGI).

Advantages

Composite restorations are bonded to tooth structure, yielding better retention, lower microleakage, minimal interfacial staining, and increased strength compared to amalgam restorations.
They are more aesthetic and conservative, so less tooth structure removal is necessary.
They have low thermal conductivity and are universally used.
Composite restorations are repairable.

Disadvantages

Potential gap formation, most frequently on root surfaces, due to polymerization shrinkage exceeding initial bond strength or improper insertion.
Technique is more sensitive, time-consuming, and costly compared to amalgam restorations.
Operating site isolation and proper bonding are crucial.
High occlusal stress areas may exhibit wear if restorative material is subject to significant occlusal forces.

Indications

Direct restorations—Class I, II, III, IV, V, and VI.
Foundations or core buildups.
Sealants and preventive resin restorations (PRR)
Aesthetic enhancements: partial/full veneers, tooth contour modifications, and diastema closures.
Periodontal splinting.

Contraindications

If operating site isolation is not possible due to oral fluids.
If all occlusal forces are on the restorative material.
Composite restorations on the root surface might have a gap at the junction. RMGI restorations might be preferred instead.

Clinical Technique

Local Anesthesia
- Contributes to a more comfortable and uninterrupted procedure, marked reduction in salivation.
Preparation of Operating Site
- Removal of plaque, pellicle, superficial stains, and calculus. Removal of materials containing flavoring agents, glycerin or fluoride, as these may interfere with acid-etch bonding.
Shade Selection
- Performed before prolonged tooth drying to avoid lighter shades. Done before bleaching. Appropriate lighting is necessary.
Shade Guide
- Specific to individual manufacturers, not interchangeable. May cross-reference with Vita Classical shade guide. Some now offer very light shades because bleaching is common.
- Selection technique: rapid selection to avoid eye fatigue. If necessary, operator should rest the eyes looking at complementary colours (blue/violet) to revitalize and re-sensitize color receptors.
- Confirmation: Small amount of material on the tooth area, close to the site, and cured provides an accurate assessment.
Pre-operative Occlusion Assessment
- Identification of occlusal contacts on the tooth(s) to be restored. Assessment also includes occlusal contacts on adjacent teeth. Use articulating paper to establish, and correct proper occlusal contact on the restoration.
Isolation
Isolation of the operative site, usually with a rubber dam or cotton rolls, is essential for proper bonding to succeed. Saliva contaminating the etched enamel or dentin would significantly lower bonding success. Further, contaminating the composite material has the potential for lower physical durability.
Bonding
Incremental Packing
Finishing and Polishing

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Description

Test your knowledge on composite restorations as discussed in chapter 8 of Art and Science of Operative Dentistry. This quiz covers the advantages, disadvantages, clinical applications, and polymerization techniques involved in composite restorations. Dive into the specifics of light curing and the properties of materials used in operative dentistry.