Upload
faculty-of-dentistry
View
301
Download
2
Embed Size (px)
Citation preview
TENSILE TESTING OF BRITTLE
MATERIAL
Faculty of dentistry Alexandria university
Mohamed hamdy fawzyMohamed Adel Abdulla
Mohamed Adel NasserMohamed said romia
By:
Mohamed assume Mohamed
Why glass break ?
Glass is brittle material
What is brittle material mean ?
Brittleness :
Tendency of a material to fracture or fail upon the application of a relatively small amount of force , impact or shock .
SIMILARLY,a variety of brittle restorative material , including dental amalgam ,cements , ceramic material , plaster and stone .
• Note:In many instances the material is much weaker in tension than in compression which may contribute to failure of the material in service .
So,Brittle material must be gripped with caution ,and any stress concentrations at the grips can lead to premature fracture .
Tensile test of brittle material
An alternative method of testing brittle material , in which the ultimate tensile strength of a brittle material is determined through compressive testing .
The method is described as the diametral compression test for tension , Brazilian testOr indirect tensile .
Stress-strain curve :
Tensile strength :
HOW CAN BRITTLE MATERIALBE USEFUL IN DENTISTRY
Although ,This material are weak but have some special properties that is not found in other material .
Dental ceramics ,
Are characterized by their refractory nature High hardness and chemical inertness .
But,
With eating Hard material
Actually,
So ,What we can do to get more nature appearance as soon as great resistance to fracture ??
Veneer
The most advanced research in dentistry shown in micro-structure Of veneer proved that: Its compliance with teeth
Not surprising to see many of discoveries and developments in this area
اال ) العلم من اوتيتم وما.......(قليال
ANY QUESTION ?