Dental Materials: Properties and Classification

Physical and Mechanical Properties of Dental Materials

Primary and Secondary Bonds

• Primary Bonds: Ionic, covalent, metallic.

• Secondary Bonds: Permanent dipole, temporary dipole, hydrogen.

States of Matter

• Solid: Crystalline or amorphous.

• Liquid: Defined by viscosity and thixotropy.

• Gas: Lacks defined shape or volume.

Key Physical Properties

• Melting and boiling points.

• Density: Relationship with volume and crystalline structure.

• Viscosity: Indicates flow characteristics.

• Thermal conductivity and expansion.

Key Mechanical Properties

• Hardness: Contributes to abrasion resistance.

• Elasticity: Importance in dental procedures.

• Stiffness: Related to proportional limit in restorative materials.

• Ductility and Malleability: Affect edge strength of materials.

• Toughness vs. Resilience: Distinction between energy absorption and recovery.

• Brittleness: Impact on restorative materials.

• Fatigue: Failure after repeated stress.

Classification of Dental Materials

• By Composition: Metals and alloys, ceramics, polymers.

• By Application: Preventive, therapeutic, restorative (direct and indirect).

• By Longevity: Permanent, temporary, intermediate.

Manipulation Variables

• Ratios of components, temperature, humidity.

• Stages of material reaction: Mixing time, working time, set times.

Shelf Life Definition

• Influenced by various variables, expiration, and stock rotation.