Nyucd Biochemistry Biomineralization

Front 1

Bone Function in humans

Back 1

skeletal support
digestion
defense
calcium reservoir
hearing
gravity perception

Front 2

The major mineral in dentin, bone, cementum, and enamel

Back 2

Hydroxyapatite (HAP)

Front 3

What is the key to creating Hydroxyapatite crystals with desired dimension for bones and teeth?

Back 3

controlling crystallization of amorphous calcium phosphate (ACP)

Front 4

Tooth developement arises from cell migration of ...

Back 4

epithelium into mesenchyme

Front 5

Epithelium and mesenchyme become ______ and ______. These layers separate to form ______

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ameloblasts and odontoblasts
extracellular space

Front 6

What is the delivery system for osteoblast and odontoblasts?

Back 6

extracellular matrix vesicle

Front 7

Where does ACP formation begin?

Back 7

mitochondria

Front 8

What contents of the matrix vesicle are released into the extracellular matrix and add to existing ACP?

Back 8

-annexin calcium transporter protein
-ATPase
-Phosphate ion transporter

Front 9

Do ameloblasts have matrix vesicles?

Back 9

NO - use other exocytotic vesicles

Front 10

What are the steps in dentin formation

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-Matrix vesicle of odontoblast reaches ECM and breaks open, releasing Type I Collagen (fibrils & scaffold--> crystal growth), SIBLING (bind within fibrils -->crystal size), and Proteoglycans (bind outside fibrils -->crystal size)
-ACP flows into fibrils and crystallizes into defined orientation within fibril where SIBLINGs and PGs are

Front 11

What does Type I collagen assemble into in dentin formation? What does it control?

Back 11

- fibrils and scaffolding
-HAP crystal growth

Front 12

Where do SIBLING proteins bind in dentin formation? What does it control?

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-inside of fibrils
-HAP crystal size

Front 13

Where do proteoglycans bind in dentin formation? What does it control

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-outside of fibrils
-HAP crystal size

Front 14

SIBLING protein that regulates gene expression in nucleus, where it modulates HAP

Back 14

Dentin matrix phosphoprotein I (DMP)

Front 15

SIBLING protein that cleaves product precursor sialophosphoprotein, is exported to ECM to modulate HAP formation, and binds to Type I collagen

Back 15

Dentin matrix phosphoprotein II (DMP-2)

Front 16

SIBLING protein that is cleavage product of sialophosphoprotein and is exported to ECM to modulate HAP formation, where it binds to type 1 Collagen
-also diffuses to ECM where it binds to amelogenin

Back 16

Dentin sialoprotein (DSPP)

Front 17

SIBLING protein that regulates HAP growth and plays role in dentin and bone remodeling (resorption) --> important in orthodontics

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Osteopontin (OPN)

Front 18

a mutation of DSPP or DMP-2 that leads to improper bind got to Type I collage
-results in a grey to yellow-brown colored tooth that can fracture easily

Back 18

Dentin Imperfecta

Front 19

Amelogenisis is the devlopment of

Back 19

enamel

Front 20

Enamel matrix protein that self assembles into scaffold (sphere) in ECM, becoming a gel network that guides the formation of HAP

Back 20

Amelogenin

Front 21

Enamel matrix protein that prevents crack propagation from enamel to DEJ and allows rod elongation

Back 21

Enamelin

Front 22

The only enamel matrix protein that is present in mature enamel is....

Back 22

enamelin

Front 23

enamel matrix protein that is located int he DEJ boundary
- provides initial crystal formation in DEJ and restricts growth of rods

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Tuftelin

Front 24

enamel matrix protein that defines sheath area of enamel rods and controls elongation of crystal

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ameloblastin

Front 25

What are the steps in enamel formation?

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-Amelogenin/EMP exported to ECM--> amelogenin forms scaffold that binds Enamel martrix proteins
-ACP flows in ECM and is organized
-ACP transforms into HAP
-Enamel Rods form
-Tooth matures, ameloblasts die, and enamel surface exposes & erupts

Front 26

abnormal enamel formation (soft and thin) due to mutation in amelogenin, enamelin, and tuftelin

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amelogenesis imperfecta (AI)

Front 27

Pros and Cons of enamel

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Pros: ceramic, insulates, resistend to dissolution, invase agents and temperature change

Cons: no regeneration, fractures

Front 28

Pros and Cons of dentin

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Pros: protein-mineral composite, fracture resistant, "plastic" (absorbs shock and better environment for odontoblasts and pulp)

Cons: porous, subject to leaks, temperature changes, invasive agent

Front 29

How are is bone similar to dentine

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-osteoblasts arise from mesenchyme
-have SIBLINGS and proteoglycans (different function)
-migrate into cell clusters, form mineral, expand
-Can be resorbed, remodeled, Ca reservoir

Front 30

What is the difference between osteoblasts and osteocytes

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Osteocytes are inactive osteoblasts

Front 31

Cellular transformation of bone are regulated by

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-SIBLINGs
-Mechanical load and gravity
-Hormones
-Diet

Front 32

Cementum is derived from ________. It contains active ________ & inactive ________. Why is remodeling so slow?

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-epithelium
-cementoblasts, cementocytes
-No blood vessels

Front 33

Cementum Protein I (CEMPI) induces _________ and expression of bone proteins

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Periodontal ligament form

Front 34

Cementum attachment protein induces...

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cementoblasts to migrate to root surface

Front 35

How is osteoporosis treated?

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Antiresorptives (bisphosphonates and fluorides) and anabolic therapy (estrogen modulators)

Front 36

Why do implants have rough surfaces?

Back 36

Increases surface area to increase osteoblast activity
-improves tissue-implant contact and bone-in growth

Front 37

What is the difference between osseointegration and fibo-osseous integration in implants?

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Osseointegration has no intervening layer at the bone-implant interface
Fibro-osseous integration has collagen rich ligament between bone and implant

Front 38

implant coated with bio-active material that stimulates bone formation and acts as a chemical bond

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Biointegration implant

Front 39

When a bone is taken from the person's own hip for the use of rebuilding tissue it is known as an...

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autograft

Front 40

type of graft that does not resorb or permit cell adaptation without immunological reaction

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allograft

Front 41

Why are organic and inorganic composites inefficient for grafting?

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no cellular response

Front 42

why is synthetic HAP innefficient for grafting?

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slow resorption

Front 43

What is the site of initial demineralization of teeth?

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Sheath

Front 44

These are the HAP crystals running from DEJ to the surface that are highly ordered, not as porous, and are surrounded by the sheath

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Prism Rods

Front 45

How does bacteria break down enamel?

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-Bacteria adheres to exposed enamel and synthesizes plaque polysaccharides
-plaque produces acids from metabolism
-multilayer film develops which cannot be reached by saliva or antibodies
-Acid retained near surface begins to dissolve porous sheath

Front 46

What can be done to reverse demineralization?

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-Calcium, Magnesium, Phosphate administration
-Polymer sealant
-ACP administration

Front 47

When can a tooth not remineralize?

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Once the prism rods begin to erodes
(absense of ameloblasts)

Front 48

non invasive caries detection that can only detect surface caries?

Back 48

HAP fluorescence

Front 49

non-invasive caries detection that can detect caries 1-2 mm in teeth

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Optic Coherence Tomography