AGD Dental Materials & Technology — Questions and Answers

Question 1: What is a common material used for dental fillings?

Glass ionomer
Zinc oxide
Composite resin (Correct answer)
Acrylic cement

Correct answer: Composite resin

Composite resin is a widely favored material for dental fillings due to its excellent aesthetic properties, as it can be matched to the natural tooth color, making restorations virtually invisible. It is a durable mixture of plastic and glass particles that is bonded directly to the tooth structure. This material is versatile, suitable for restoring decayed or fractured teeth in both anterior and posterior regions.

Question 2: Why is curing light used in restorative dentistry?

To disinfect the mouth.
To dry the saliva.
To harden resin materials by light activation (Correct answer)
To measure tooth color.

Correct answer: To harden resin materials by light activation

Curing lights are essential tools in restorative dentistry, emitting a specific wavelength of blue light that activates photoinitiators within resin-based dental materials like composite fillings and bonding agents. This light energy causes the material to polymerize and harden rapidly, allowing the dentist to sculpt and set the restoration efficiently. Proper curing is critical for ensuring the strength, durability, and longevity of the dental restoration.

Question 3: Which material is most suitable for making dental crowns?

Wax
Zinc phosphate
Porcelain or zirconia (Correct answer)
Alginate

Correct answer: Porcelain or zirconia

Porcelain and zirconia are highly suitable materials for dental crowns due to their exceptional aesthetic qualities, closely mimicking the natural appearance and translucency of teeth. Zirconia also offers superior strength and durability, making it ideal for posterior teeth, while porcelain provides excellent aesthetics for anterior restorations. Both materials are biocompatible and resistant to wear, ensuring long-lasting and functional crowns.

Question 4: What is CAD/CAM technology used for in dentistry?

To enhance x-ray images.
To diagnose gum disease.
To digitally design and fabricate restorations (Correct answer)
To store patient records.

Correct answer: To digitally design and fabricate restorations

CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) technology has revolutionized restorative dentistry by enabling dentists to digitally design and mill dental restorations such as crowns, inlays, onlays, and veneers directly in the office. This process involves scanning the prepared tooth, designing the restoration on a computer, and then fabricating it from a block of material using a milling machine. It significantly reduces treatment time, enhances precision, and improves efficiency.

Question 5: Which cement is known for its fluoride-releasing property?

Resin cement
Glass ionomer (Correct answer)
Polycarboxylate
Zinc phosphate

Correct answer: Glass ionomer

Glass ionomer cements are unique among dental materials for their ability to release fluoride ions over time, which helps to prevent secondary caries (cavities forming around the restoration). This fluoride-releasing property makes them particularly beneficial for restorations in high-caries-risk patients or as a base/liner under other restorative materials. They also form a chemical bond with tooth structure, offering good marginal seal.

Question 6: What is the main advantage of digital impressions?

They are reusable.
They require more time to process.
They eliminate physical impression materials (Correct answer)
They distort easier.

Correct answer: They eliminate physical impression materials

Digital impressions utilize intraoral scanners to capture a precise three-dimensional image of the patient's teeth and gums, completely eliminating the need for messy and often uncomfortable traditional impression materials. This technology offers increased accuracy, improved patient comfort, and allows for immediate digital transmission of the impression to the dental lab. It streamlines the restorative process, reduces material waste, and enhances overall efficiency.

Question 7: Which material is typically used for temporary restorations?

Zirconia
IRM or temporary acrylic (Correct answer)
Gold alloy
Resin composite

Correct answer: IRM or temporary acrylic

Intermediate Restorative Material (IRM) and temporary acrylics are commonly employed for temporary restorations in dentistry. IRM, a zinc oxide-eugenol based cement, is known for its sedative effect on the pulp and good sealing properties, while temporary acrylics are frequently used for provisional crowns or bridges. These materials protect the prepared tooth, maintain space, and provide aesthetics and function while a permanent restoration is being fabricated.

Question 8: What is alginate primarily used for?

Final crown prep.
Implant placement.
Preliminary dental impressions (Correct answer)
Tooth polishing.

Correct answer: Preliminary dental impressions

Alginate is an irreversible hydrocolloid material primarily used to take preliminary dental impressions. These impressions are typically utilized for creating study models, custom trays, or for diagnostic purposes due to their ease of use and cost-effectiveness. Its ability to capture sufficient detail for these applications makes it a fundamental material in general dental practice.

Question 9: What is the key property of amalgam as a restorative material?

Aesthetic appeal
Low durability
High strength and longevity (Correct answer)
Transparent finish

Correct answer: High strength and longevity

Dental amalgam, an alloy of mercury, silver, tin, and copper, is renowned for its exceptional strength, durability, and longevity, particularly in posterior teeth where biting forces are significant. It has been a reliable restorative material for over a century due to its robust resistance to wear and fracture. While its aesthetic appeal is limited, its physical properties make it a highly effective and long-lasting choice for many restorations.

AGD Dental Materials & Technology

What is a common material used for dental fillings?