Dental Materials Science Flashcards

Which type of gypsum product has the highest compressive strength and is used for die fabrication?

Answer: Die stone (Type IV)

Type IV die stone has the highest compressive strength among gypsum products, making it ideal for accurate die fabrication.

What is the primary advantage of using addition-cured silicone (VPS) impression materials over condensation silicones?

Answer: Dimensional stability with minimal shrinkage

Addition-cured silicones (VPS) produce no by-products during polymerization, resulting in excellent dimensional stability and minimal shrinkage.

The elastic modulus (stiffness) of a restorative material is most relevant when evaluating:

Answer: Resistance to deformation under occlusal load

Elastic modulus describes a material's stiffness and its ability to resist deformation under applied occlusal forces.

Which base metal alloy component is primarily responsible for the natural oxide layer that improves ceramic bonding in PFM restorations?

Answer: Beryllium or tin

Beryllium and tin in base metal alloys form surface oxides during oxidation that chemically bond to porcelain for improved ceramic adhesion.

A dental wax pattern that exhibits 'flow' at mouth temperature would most likely cause:

Answer: Distortion of the final casting

Excessive wax flow at oral temperature causes pattern distortion before investing, leading to an inaccurate final casting.

The phenomenon where porcelain and metal expand and contract at different rates during firing and cooling is quantified by:

Answer: Coefficient of thermal expansion (CTE)

The coefficient of thermal expansion (CTE) must be closely matched between porcelain and metal to prevent cracking or delamination.

In casting alloy selection, which property best indicates a material's ability to be shaped into thin margins without cracking?

Answer: Ductility

Ductility is the ability of a metal to be deformed plastically without fracturing, essential for burnishing thin casting margins.