Chapter 2 Oral Environment and Patient Considerations Flashcards
Factors of the oral environment include?
Moisture, differing stresses, temperatures, and acid levels
Materials to be used in the mouth must be?
Biocompatible, durable, nonreactive in acid or alkaline conditions, compatible with other materials, and esthetically acceptable
Biocompatibility
Materials must benefit the patient
Must not adversely affect living tissue
Biocompatibility along with short-term and long-term functionality
Biomechanics
Application of engineering principles to biological systems
Function of a material
Dependent on the properties of the material as well as what the material is being asked to do
Excessive wear of a material may be due to what?
May be due to variations in forces applied
Measure of strength of muscles of
mastication during normal chewing
Biting force
Normal masticatory forces on the occlusal surface of molar teeth
Average 90 to 200 pounds per square inch
Can increase as much as 28,000 pounds per square in on a cusp tip
Denture wearers have how much less force during mastication
40%
Types of masticatory forces
Compressive, shearing, tensile, torque
Types of stress and strain
Stress, strain, flexural stress, fatigue failure
Galvanism
When two dissimilar metals make contact and a small amount of electricity is generated
Coefficient of thermal expansion (CTE)
Material property that indicates the extent i which a material expands upon heating
Percolation
When oral fluids penetrate the space between a restoration and tooth, can happen when the coefficient of thermal expansion of a restorative material does not match that of the tooth structure
Retention
Ability to maintain position
without displacement under stress, can be mechanical or chemical
Film thickness
Thickness of layer formed by dental cements or resins after setting
Surface energy
Determines the attraction of a surface’s constituent atoms
Interface
Surface between the walls of the tooth structure/preparation and restoration
Microleakage
Seepage of harmful materials from a restoration, responsible for much recurrent decay, marginal staining, postop decay
Three components of color
Hue, chroma, value
Color of teeth determined by the amount of light that passes through them
Transparent, translucent, opaque
Metamerism
When two colors appear to match under one lighting but not another
