Card Set Information
Chapter two part two
Acceptable dental materials need to expand and contract _______ with the ______
Excessive expansion may lead to What?
Excessive contraction may lead to what?
leakage of fluids and bacteria into the open gaps, producing sensitivity
Measurements of expansion and contraction=what?
Coefficient of Thermal Expansion (CTE)
Large difference between CTE and tooth structure causes __________; and ___________ may occur
CTE = 11
Thermal conductivity = 2.0
CTE = 8
Thermal conductivity = 1.30
CTE = 20-28
Thermal conductivity = 54
CTE = 15
Thermal conductivity = 350
CTE = 15
Thermal conductivity = 2.5
CTE = 26-40
Thermal conductivity = 2.60
________ material may reduce thermal conductivity
nonmetals such as ceramics, resins, cements, enamel, and dentin are very poor conductors, and poor conductors can be used as what?
________ is a natural insulator
What is one of the best thermal conductors?
When there is a large difference between the CTE and the restorative material as for amalgam and tooth structure, the percolation will be __________
The reactions of some components when they are mixed may result in the production of heat
Name 4 'other' factors in material selection
the ability of a material to maintain its position without displacement when under stress
What might help secure retention of a material?
mechanical chemical adhesion or bonding
What type of retention uses undercuts?
Dental cements retain restorations by __________ and/or __________ connecting the two surfaces
___________ of materials occurs when the tooth surface is prepared through the use of an acid-etch technique to create microscopic pores in enamel and dentin.
What kind of retention is using etch material?
when the fluid fills the poors created by the etch it is mechanical; then the restorative materials on top of that chemically adhere to that material
What are 6 factors that can affect the bond strength or the success of a material as an adhesive?
surface characteristics of the tooth
When liquids bead up on a surface, the surface has ______ surface energy
Lliquids generally wet or spread over high surface energy surfaces better such as what? (3)
What happens if the interface of a resoration is not sealed?
fluids and microorganisms can penetrate between tooth structure and restorative material
What is responsible for much of the recurrent decay, marginal staining, and postoperative sensitivity?
Tubule fluid flow causes what?
not adversely affecting living tissue
Nickel and acrylic hypersensitivity are caused from what factor?
It has been reported that a significant percentage of people have skin allergies or hypersensitivity to some metals in particular what 2?
nickel and acrylics
What are the 3 components that describe the resultant color?
intensity or strength of color
describes how light or dark the color is
the dominant color of the wavelength detected
colors look different under different light sources
Why is the detection of restorative material critical in dental hygiene?
so we can recognize what is a restoration or tooth and not damage it
What are 4 sources that can have adverse affects on restorations that are used in dental hygiene?
sonic and ultrasonic scaling
air and polishing
What are 3 ways to detect different restorative materials?
visual, light, air, magnification
What is the most reliable way of detecting a restorative restoration with tooth colored fillings?
What is an example of galvanism?
amalgam contacting gold
An excessive film thickness may cause what?
improper seating of restoration
microleakage may be responsible for what?