Materials used in dentistry

Question 1

Metals

Answer 1

• Form positive ions by losing electrons
• Good conductors of heat and electricity
• Malleable, ductile and shiny
• Used for crowns, bridges, orthodontic appliances, and dental implants.
• Solid at room temperature

Question 2

Alloys

Answer 2

• Homogeneous mixtures of 2 or more metals
• Crystalline structure and opaque
• Solid expect for amalgam
• Can deform plastically or elastically
• Uses: Restoration, Crown bridge, orthodontic brackets, and wires.

Question 3

Types of Metals and Alloys:

Answer 3

• Noble metals
• Precious metals
• Non-noble metals
• Noble alloys
•Non-noble alloys

Question 4

Chemical corrosion

Answer 4

The chemical change of metals in the oral cavity

The main corrosive factor is Saliva

Other factors: pH, oral bacterial plaque

Question 5

Noble alloys

Answer 5

• Commonly used in crowns, bridges, and dental restorations.
• Highly compatible with tissues, causing minimal reactions.
• Exhibits excellent mechanical strength and durability.
• Generally more expensive due to the presence of precious metals.

Question 6

Non-noble alloys

Answer 6

• Temperature resistance and modulus of elasticity superior to noble alloys
• Lower biocompatibility
• Lower cost

Question 7

Co-Cr alloys

Answer 7

• Used for crowns, bridges, and partial dentures.
• Highly elastic, ideal for metal-ceramic crowns and bridges.
• Low density, resulting in lightweight dental restorations.
• High temperature resistance, suitable for metal-ceramic restorations.
• Superior to Ni-Cr alloys due to reduced release of metal ions.

Question 8

Dental amalgam

Answer 8

• Highly durable and resistant to wear and tear
• used for dental fillings
• silver-coloured appearance
• well tolerated

Question 9

Titanium and Ti alloys

Answer 9

• Highly biocompatible, promotes osseointegration.
• High strength-to-weight ratio, making it ideal for dental implants.
• Forms a stable oxide layer, resisting corrosion and enhancing biocompatibility.
• Used for dental implants, crowns, bridges, and endodontic instruments.

Question 10

Polymers: PMMA

Answer 10

➢ Biocompatibility well-tolerated, but incomplete polymerization can lead to
cytotoxic effects.
➢ Moderate strength, suitable for various dental applications.
➢ Used for artificial teeth, denture bases, orthodontic appliances, and temporary crowns.