Card Set Information
chapter two part one
materials placed in the oral cavity must be what 5 things?
nonreactive in acid or alkiline conditions
compatible with other materials
What are 5 environmental factors that affect the compatibility or materials?
time/how long materials are expected to be used
Therapeutic agents are generally used for _______ periods of time, where as restorative agents are expected to remain in contact with tissues for ________ lengths of time
What is an example of a material that is therapeutic in small quantities but may be irritating or toxic with longer or larger doses?
true or false. All materials contain potentially irritating ingredients
Dentists must consider the performance of a material on the basis of knowledge of its ________ and the intended ________ of the material
Much as an engineer would do, a dentist must design a bridge while taking into consideration what 3 structures?
What are 3 different types of forces that materials must be able to withstand in varying degrees of force or load?
mastication (cushioned by food)
Normal masticatory forces on the occlusal furfaces of molar teeth average ____ to ______ pounds; and can increase to as much as ______ pounds per square inch on a cusp tip
Masticatory forces are ________ in incisor areas
each tooth is ideally suited for specific types of _________
That are the 3 basic types of masticatory force?
force applied to compress an object. Posterior teeth are ideally suited for this type of force.
Why are posterior teeth ideal for compressive force?
because of the large occlusal surface and the multi-rooted base; it will resist a crushing force
force applied in opposite directions to stretch an object, when biting forces are used to stretch a material the tooth is exerting this type of force
force applied when two surfaces slide against eachother or in a twisting or rotating motion. An incisor used for cutting is an example of this
When a force is exerted on a tooth, the tooth or material creates resistance to couteract the force. This INTERNAL force, which resists the applied force is called what?
amount of change or deformation the force prodecued, ie. distortion or deformation
true or false. teeth have flexure and implants don't.
______ and _______ _______ more closelly replicated enamel in compressive strength, but _________ falls short.
a metal wire bent repeatedly will eventually break, this is an example of what?
true or false. humidity, temperature, and pH fluctuations may increase fatigue failure.
What is the normal resting pH of saliva?
the breakdown of most restorative materials is directly related to the effects of ________, __________, and ___________
Why are gold and porcelain retained in the oral environment for many years?
because of their insoluble nature
What are 4 examples of acid or alkiline that the oral cavity is continually in contact with?
desireable materials to use have what 2 qualities that have to do with moisture and acid levels?
low water sorption
Staining of resins and acrylics from repeated exposure to coffee, tea, and other dyed beverages is due to what?
What factors make electrical current possible in galvanism? (3)
the phenomenon of transmission of electrical current between 2 dissimilar metals
Pulpal stimulation from the electric current in galvanism
Galvanism will decrease with what?