Layers Dentin Flashcards
Which is the must abundant tissue in the oral cavity and what’s mechanical and optical function ?
Dentin
Provide elasticity , resistant to dental complex .
Highly flurecent tissue due to photochrome ( protein)
What’s dentin color ?
Reddish-yelllow
High chroma and opacity
What’s primary and secondary dentin ?
Primary since formation of tooth germ
Secondary at the moment of contact opposing teeth continue through life
Along the tooth structure describe the differences between dentin saturation and chromacity :
Center of tooth more chromatic
Close to surface become less saturated
A2 tooth , bear pulp A3
Deep dentin become closer too pulp , pulp located more cervically so in cervical area chromacity and opacity are more ( where the tooth is thicker )
As we go incisally chroma decrease
What’s happen to dentin color with aging ?
Slow increase in red-orange component of tooth , become more chromatic .
Why does dentin changes color by time that make the transition from originally white opaque dentin to darker and more translucent ?
- there is thickness changes + color both related to
- By decreased pulp size that get replaced by apposition of secondary dentin & sclerosis of dentinal tubules making it less permeable .
- Hydration of tooth and addition of pigments to dentin structure ( more hydration = more dark (low value) for both dentin and enamel ) .
- Mineralization , let dentin loss opacity over the time and become more transparent ( min process near DEJ ).
- Physiological wear of enamel makes dentin more visible
What’s the relation between mineralization and chroma and permeability and chroma ?
Explain from sour sea
Does the dentin only opaque ?
No it’s also translucent cause it contain its organic and non organic parts
When we restore small restoration in which translucency level of material we will interast ?
Small resto means that healthy surround tooth structure will be present to choose more translucent material to display and reflect the underlying tooth structure .
When we restore large restoration in which translucency level of material we will interast ?
Opaque material for build up , cause if it translucent it would be unable to mask the black ground of oral cavity .
What’s the thickness of 1mm human dentin and enamel and composite ?
Human : 16.4 & 18.4
Composite : 6.3 & 17.2
Higher numbers for translucency
Opaque is 0.0
What’s young teeth dentin chroma , enamel value ?
Low chroma
High value
The value of enamel hides the dentin and increase tooth value.
What’s adult teeth dentin chroma , enamel value ?
Chroma : moderate
Value : medium
Enamel is slightly increase tooth value
What’s old teeth dentin chroma , enamel value ?
Chroma : high
Value : low
Enamel increase tooth value very little
What’s cooperation between chroma and value ?
Chroma for dentin as it increase it will decrease value ( tooth brightness )
There is several factors the affect the enamel by age which leading to enamel loss or discoloration decreasing it value and increase chroma
Or by increasing the chroma the value decrease
So as we grow chroma grow , less years remain mean less value
Explain dentin elasticity and how give it strength
Dentin the most resistant human tissue , but not the hardest ( it’s related to high elasticity ) and responsible for enamel support and pulp protection .
In absence of dentin enamel can’t withstand cause its substrate .
Its has resistance to traction , compression , shear forces .
Enamel and dentin they are different composite when we need dentin replace it by dentin .
Explain dentin elasticity and how give it strength
Dentin the most resistant human tissue , but not the hardest ( it’s related to high elasticity ) and responsible for enamel support and pulp protection .
In absence of dentin enamel can’t withstand cause its substrate .
Its has resistance to traction , compression , shear forces .
Enamel and dentin they are different composite when we need dentin replace it by dentin .
Large percentage of light that hits the dentin is reflected back , this light returned with more energy than original what’s explain these ?
Fluorescent of tissue that posses photochrome and fluorophore
What’s the must fluorescence part of our body ?
Dentin layer and it’s proteins that bind to the enamel the most in our body , even enamel fluorescence is in less degree .
Under which type of light fluorescence is evident , how it appear under natural light ?
Evedent under fluorescent light , but can seen but less obviously under natural light .
Cause some invisible light is bounced back from the teeth with higher energy (visible light ) it impair ( ينعم ينعش) vitality of natural teeth.
What does. Lack of fluorescence mean ?
Devitalized teeth
Pathological condition
Prosthetic teeth
There is some thing called fluorescent material ?
Yes , any resto material lack it not considered to be an optimal esthetic material .
In Endo teeth what’s the considerations in layering ?
These teeth lost fluorescent , so is appropriate to restore some layers of these teeth with more fluorescent material than would normally be used.
What’s inner glow ?
The vital appearance of teeth due to fluorescence that light emission from inside .
