Exam 1 Flashcards
Name two remineralizing agents.
Casein phosphopeptide
Amorphous calcium phosphate
Are adhesives considered direct or indirect restorative materials?
Indirect
What is a definitive restoration?
The final, long-term treatment
What are four tissue engineering strategies?
Injection of cells
Guided tissue regeneration
Cell induction
Scaffolds
Explain guided tissue regeneration
A surgical procedure for regenerating tissue by enhancing the opportunity for one cell type to proliferate
Describe cell induction
Providing growth factors and developmental proteins to the site of interest to induce the progenitor cells to differentiate into the desired tissue
Explain scaffolds in regards to tissue engineering.
Scaffolds promote new tissue formation by providing a surface and void volume that encourages migration and proliferation of the desired cell types
By weight, mature enamel is composed of ___ inorganic material, ___ organic material, ___ water.
96%
1%
3%
What shape are enamel crystals? How long can they be? How are they packed?
Long hexagonal crystals
May span entire enamel thickness
Packed into enamel rods or prisms
Individual enamel crystals are coated with ____ which plays a role in ____, this appears to increase enamel ____
Lipid/protein
Mineralization
Toughness
What is the difference between type1,2,and 3 enamel etching?
Type 1: prism core is etched
Type 2: prism periphery is etched
Type 3: mixed pattern of both
Near the DEJ, the enamel is more or less difficult to etch? Why?
It is more difficult to etch because the enamel is aprismatic
HA in enamel and dentin is ___ deficient and ____ rich.
Calcium deficient
Carbonate rich
Odontoblasts differentiate from the ___ cells of the dental papilla
Outer
Pulp develops from the ___ central cells of the dental papilla
Central
What structure was the precursor to the DEJ in development?
Basement membrane
Why are dentin tubules more dense towards the pulp?
Odontoblasts start at the DEJ but migrate inwards. This is why you find odontoblasts lining the pulp chamber
Dentin is composed of ___ HA, ___ organic material, ___ fluid.
50%
30%
20%
Which contains more organic compounds in dentin… Intratubular or intertubular dentin?
Intertubular dentin contains more organic compounds
As dentin is etched which is preferentially removed, the intertubular dentin or the intratubular dentin? Why?
Intratubular dentin is more easily removed because it has less organic components
Is scalloping of the DEJ more prominent in the anterior or posterior teeth? Why?
Posterior teeth because it is most prominent where it is subject to more functional stresses
What is the difference between adhesive wear, corrosive wear, surface fatigue wear, and abrasive wear?
Adhesive wear: disruption of micro junctions
Corrosive wear: physical removal of protective layer due to chemicals
Surface fatigue wear: free particles contribute to high localized stress and produce surface cracks
Abrasive wear: involves a harder material rubbing against a softer material
What is wetting power?
The tendency of a liquid to spread on the surface of a material
What is the index of refraction?
The ratio of the velocity of light in air to its velocity in the medium. Light actually changes velocity when it changes its medium!
What is the coefficient of thermal expansion?
The change in length per unit length of a material for a 1 degree change in temperature
What is electromotive force?
The voltage developed by any source of electrical energy
Explain galvanism
Results from difference in electrical potential between dissimilar fillings in opposing or adjacent teeth. Can cause pain and/or corrosion
What is pycnometry?
A technique used to determine the density of a material
What is rheology?
The study of deformation and flow of a material
Name 3 features that direct in-vitro testing can test
Cystotoxicity/proliferation
Functionality (do they still make the same proteins and stuff?)
Mutagenesis (do cells change core genetic functions
What is indirect in-vitro testing?
Cells placed on opposite sides of a relevant barrier of a material
Is zinc oxide cytotoxic? Is it disruptive in usage tests?
Yes it is cytotoxic, but it is not disruptive in usage tests because it doesn’t penetrate dentin very well
What can occur if the material is not bound to dentin strong enough?
Microleakage. This can lead to pulpal irritation, which can also lead to the reestablishment of caries.
Does the removal of the smear layer increase or decrease the potential for micro leakage?
Increase
MMPs are ___ dependent ____. That degrade the ___ (mostly ____)
Zinc
Proteases
ECM
Collagen 1
What is one reason why amalgams last longer than resin?
Resin forms a hybrid layer with dentin that is susceptible to attack by MMPs
How do bacteria stimulate MMPs?
Bacteria create acidic conditions which activate host MMPs and can interfere with the function of TIMPs
Where do MMPs come from?
They are produced by many cell types (fibroblasts, odontoblasts, osteoclasts, macrophages, neutrophils)
Generally associated with inflammation.
Also secreted in saliva
Which is worse… An amalgam with lots of copper or lots of mercury?
In Vivo and usage tests show that high copper amounts are cytotoxic. (So is Mercury, but less so)
What role does polyacrylic acid play in regards to glass ionomers?
They can be used as cement, lining material, base, and restorative material
Calcium hydroxide is frequently used as a lining material. It is cytotoxic. Is it better or worse when combined with resin?
Calcium hydroxide is less cytotoxic when combined with resin
What element is used in cements for lining and restorations?
Zinc
Which is more cytotoxic… Zinc phosphate or zinc polyacrylate?
Zinc phosphate is more cytotoxic. But a thick dentin wall can reduce its effect of cytotoxicity
true or false, ZOE (a zinc based cement) has anesthetic properties?
True
What is mineralized trioxide aggregate?
Cytotoxicity?
It is a non-resin cement. (Portland cement (modified))
Not cytotoxic! Actually increases cell proliferation and synthesis of matrix specific proteins.
Resin composites are highly cytotoxic to what cell in particular?
Fibroblasts
What are some things that cause resorption of bio materials?
Combo of physiological conditions, phagocytosis, and digestion of cell products
