enamel and dental caries Flashcards
to outline the mechanism of underlying progression of enamel and dentine to examine the microstructure of both enamel and dentine and how it affects the carious process to draw comparison between two tissues to outline the physiocochemical process by which caries cause destruction to outline the pulp-dentine complex and how it provides a limited defence mechanism to examine the structure of a typical tooth surface enamel caries lesion and an occlusal pit lesion
what is the definition of dental caries
it is a localised, chemical dissolution of the tooth surface bought about by metabolic activity in a microbial deposit coving the tooth surface at any given time
what is the dental caries promoted and maintained by
by frequently dietary supply of fermentable carbs
where can dental caries attack
pits
fissures
grooves
especially during eruption and approximate surfaces
what is the percentage of mineral component of the tissue by weight
95%
where is the mineral content the highest
highest at the surface and decreases as it reaches the ADJ
what is the water content in volume in enamel
10%
what is the water content in volume in dentine
20%
what is the residual content by weight in enamel of water
3%
what is the residual content by weight in dentine of water
10%
what is the residual content by weight in enamel of protein
1%
what is the residual content by weight in dentine of protein
20%
what are the crystal dimensions in enamel (w x t)
68 x 26nm
what are the crystal dimensions in dentine ( w x t)
35 x 10 nm
what is the length of the crystal in enamel
7mm
what is the crystal length in dentine
indeterminate
what are the physical properties of human enamel
highly mineralised
withstands shearing forces
abrasion resistance is high
BUT brittle
what happens with the loss of the dentine support
unsupported enamel can fracture resulting in cavitation
what happens to hardness of enamel as we move towards the ADJ
DECREASES
what happens to the density of the enamel as we move towards the ADJ
DECREASES
what re the physical properties of dentine
flexible
poor abrasion resistance
why is dentine flexible
due to its organic matrix and tubular architecture
how is enamel considered
it is considered as microporous
what is the structure of the outermost enamel
it is rather porous
what developmental features can be seen in the enamel microstructure
irregular tissues and micropores