dat 113- Composite Resin Restorative Materials

What is composite resin?

A restorative material made of polymer and ceramic components.

What are the three components of composite resin?

Resin matrix, fillers, and silane coupling agent.

What is the resin matrix commonly made of?

Bis-GMA.

What are examples of composite fillers?

Silica and glass.

What does the silane coupling agent do?

It bonds the filler to the resin.

What is macrofilled composite?

An early generation of composite containing large filler particles.

What filler size is associated with macrofilled composite?

Approximately 10–25 μm.

What is the filler content of macrofilled composite?

Approximately 70–80%.

What is a disadvantage of macrofilled composite?

It has a rough surface.

What is microfilled composite?

A composite containing very small filler particles.

What filler size is associated with microfilled composite?

Approximately 0.03–0.5 μm.

What is the filler content of microfilled composite?

Approximately 40–50%.

What are advantages of microfilled composite?

A smooth surface and translucency.

What are disadvantages of microfilled composite?

Lower strength and increased thermal expansion.

What is hybrid composite?

A composite combining filler characteristics to provide strength, wear resistance, and esthetics.

What filler size is associated with hybrid composite?

Approximately 0.5–1 μm on average, with particles up to 3 μm.

What is the filler content of hybrid composite?

Approximately 75–80%.

What are advantages of hybrid composite?

Strength, wear resistance, esthetics, and polishing ability.

What newer filler development is mentioned for composites?

Engineered fillers in the nanometer range.

What other types of composite materials are mentioned?

Flowable composites, pit-and-fissure sealants, and core buildup composites.

What are the general advantages of composite resin?

Tooth-colored, esthetic, less tooth removal, durable for small or moderate restorations, moderate wear and fracture resistance, low allergy potential, and one-appointment placement.

What are the general disadvantages of composite resin?

Moisture sensitivity, staining or discoloration, lower strength and faster wear than amalgam, polymerization shrinkage, and higher thermal expansion than tooth structure.

Why can composite resin require less tooth removal?

Adhesive bonding allows the restoration to bond to tooth structure.

What is polymerization shrinkage?

The shrinkage that occurs as composite resin hardens.

What can polymerization shrinkage cause?

Marginal gaps, microleakage, sensitivity, and recurrent decay.

How does composite resin compare with amalgam in strength and wear?

Composite is generally weaker and wears faster than amalgam.

What is chemically cured composite?

A composite supplied as two pastes that are mixed to initiate polymerization.

What is found in the base paste of chemically cured composite?

Benzoyl peroxide (BPO) initiator.

What is found in the catalyst paste of chemically cured composite?

A tertiary amine activator.

How is chemically cured composite activated?

Equal portions of the two pastes are mixed.

What is light-cured composite?

A single-paste composite activated by a curing light.

What wavelength activates light-cured composite in the provided material?

Approximately 470 nm bright blue light.

What is an advantage of light-cured composite?

The operator controls the working time before curing.

What is dual-cured composite?

A composite activated by both light and chemical curing.

What is an advantage of dual-cured composite?

It can continue to set even when light cannot reach the material.

When is dual-cured composite useful?

Where the curing light cannot adequately reach.

What do fillers do in composite resin?

They strengthen the material and improve wear resistance.

How do large filler particles affect the composite surface?

They tend to produce a rougher surface.

How do small filler particles affect the composite surface?

They tend to produce a smoother surface.

How does increasing filler content generally affect composite resin?

It increases strength and reduces the amount of resin.

What is the resin component important for?

Esthetics and smoothness.

Why is composite resin placed in increments?

Because curing light penetrates only a few millimeters.

What is the approximate shrinkage of composite resin?

Approximately 2%.

How does incremental placement help?

It reduces shrinkage in each increment and helps reduce gaps, microleakage, and recurrent decay.

Why should uncured composite be kept away from the pulp?

Uncured composite can damage the pulp.

What is the first step in the composite restoration sequence?

Diagnose the lesion.

What is the next step after diagnosis?

Select the shade.

What happens after shade selection?

Isolate the tooth.

What happens after isolation?

Remove caries and prepare the tooth.

What happens after tooth preparation?

Apply etchant and adhesive, then cure as directed.

How is composite placed?

In increments, curing each increment individually.

What steps follow composite placement?

Contour, check contacts, polish, and check occlusion.