Mineralization (Chun) Flashcards
Three mineralized tissues of tooth
-Enamel -Dentin -Cementum (Also bone)
______ is the process by which organisms produce mineral to stiffen or harden tissues to withstand mechanical forces. Those tissues are called mineralized tissues.
Biomineralization
In dentin, cementum, and bone, mineralization is based on ______. In enamel, it depends on _______.
-Collagen -Enamel proteins
The most common mineral present in biomineralization is _______.
Hydroxyapatite
The structure of calcium hydroxyapatite Ca10(PO4)6(OH)2 is a highly specific arrangement of ______ and _____ ions that can form other structures as well, as in calculus.
-Calcium -Phosphate
Mineral forms by the precipitation of ________.
Ions from solution
______ is the concentration of the ions that are supplied. The Solubility product is dependent on _____. The precipitation of a mineral depends on the concentration and degree of saturation.
-Ionic Product (IP) -pH
What do the lines represent?
IP and Ksp (at equilibrium)
What does left and below the lines represent?
IP < Ksp (demineralization)
When mouth is in acidic environment (lemons, etc.)
What does right and above the lines represent?
IP > Ksp (remineralization)
(Fluoride rinse)
What is required for biomineraliation?
- Cells, which control environment and proteins secreted
- Cells create compartment so that ions and proteins are concentrated
- Organic: Matrix (proteins) and Solubles (ions)
- Inorganic: Mineral and Impurities
Each tissue is eager to shape minerals, so they can obtain different shapes. These ______ are hexagonal.
Crystals
Crystal growth: Inital nucleation events are controlled locally by _______ and by mineral nucleators and inhibitors.
Concentrations of mineral ions
Crystal growth is influenced by ______.
Environment
Crystal growth: _______ can bind selectively to different surfaces of the crystal, preventing further growth and thereby determining the final size of the crystal.
Noncollagenous proteins
The _____ provides loci to bind matrix proteins. Acidic and phosphorylated matrix proteins have an affinity for ______, which attract ______, and create a _______.
- Collagen fibril
- Calcium ions
- Inorganic phosphates
- Crystal nucelus
What are the non-collagenous proteins?
Secretory Ca-binding phosphoproteins (SCPP)
Secretory Ca-binding phosphoproteins (SCPP) form a _________.
cluster of genes
Genes to the right of SPARCL1 (acidic) (dentin and bone)
- DSPP
- SMP1
- IBSP
- =OPN
Genes to the left of SPARCL1 (Rich in proline and glutamine) (Enamel, milk, saliva)
- AMEL
- ODAM
- AMTN
- AMBN
- ENAM
All genes of gene cluster share same ancestral gene (______), have a _______ (secreted into matrix), bind to ______, have the same structure of ______, and have _______ on serine.
- SPARCL1
- Signal peptide
- Calcium
- Exon-intron
- Phosphorylation
Enamel:
- _____ origin
- Formed in _____
- _______ are secreted
- ___% mineral
- Epithelial
- Enamel organ
- Enamel proteins
- 95%
Bone, Dentin, Cementum:
- _____ origin
- Formed in _____
- Dependent on _____ and _____
- ___% mineral
- Mesenchymal
- Matrix vesicle
- Collagen type 1 and non-collagenous proteins
- 45-67%
_______ are expelled from cell and offer a compartment where ions can be concentrated and minerals can be formed. As minerals grow, they puncture vesicle and provide an ______ for further growth inside the vesicle. Proteins of the ____ continue to control crystal growth.
- Matrix vesicles
- initiation
- ECM
Collagen fibrils provide a _____ for the deposition of the mineral phase in a highly organized structure. Non-collagenous proteins bond to holes between collagen fibrils and initiate mineralization. Dark bands are holes filled with minerals.
Scaffold
Ameloblasts are of _______ origin and are connected to each other by tight junctions. Closes space completely. Acts as a barrier for mineralized dentin.
Epithelial
Ameloblast membrane is ruffled with invaginations and surrounds the dentin crystals and mineralized collagen fibers. The ameloblasts start secreting proteins, and the ________ starts (mineralization front). Travel in same direction as collagen fibers.
ribbon formation
Dentin makes up root and coronal portion and is made my odontoblasts. Odontonblasts have ______ and secrete matrix called ______.
- Processes
- Predentin
Dentin Sialophosphoprotein (DSPP) is expressed by one gene and cleaves to give rise to _______, ________, and ______. DPP is highly phosphorylated due to _______. It is very acidic and can bind calcium.
- Dentin phosphoprotein (DPP)
- Dentin sialoprotein (DSP)
- Dentin glycoprotein (DGP)
- Serine
DSP is localized to _____, _____, _____, and ______.
- Dentin
- Cementum
- Pulp
- Alveolar bone
DSP is found around the ______ in peritubular dentin. Collagen is found in intertubular dentin.
Odontonblast processes
_______ covers and lines the root surface and makes connection to periodontal ligament.
Cementum
_______ cementum is found on coronal portion of root, and _______ cementum is found at the apical portion.
- Acellular
- Cellular
Cementoblasts secrete a matrix that later mineralizes. The unmineralized matrix is called _____, and when cells become embedded they are called ________.
- Cementoid
- Cementocytes
Cementum: Osteopontin
Structure: A lot of _______; _______ to bind calcium; residues that can facilitate an attachement to cells, _____ can bind to inigrin receptors on cells and collagen.
Functions: Cell _____ and inhibition of _________.
- Phosphorylation
- Aspartic acid
- RGD
- Attachement
- HA crystal growth
Osteopontin accumulates between the ______ portions of the _______.
- Inserted
- Extrinsic collagen fibers
Bone Sialoprotein:
Structure
- Phosphorylated, acidic
- _______ bind to calcium
- Cell attachment site (____)
Function
- Nucleation of ______
- Binding site for _____
- Anchchor protein to _____ before transferring to the collagen fibrils
- Glutamic acids
- RGD
- HA
- HA
- Cell surface
BSP localizes to acellular and cellular ______ and ______.
Cementum and bone
Enamel does not contain any cells. Cells are dying as tooth erupts. Cells that make enamel are called _______(tall polarized cells). Apical portion forms process called _______.
- ameloblasts
- Tomes’ process
Enamel proteins are unique: Amelogenein
Structure:
- ____% of enamel matrix
- Alternative splicing
- Cleavage by MMP20 and Klk4
- Phosphorylation
- Intrinsically ______
- Self Assembly into _____
Function:
-Regulates ________
- 80-90%
- Disordered
- Nanospheres
- Crystal spacing
Hard tissue formation involves ____ situated close to a blood supply, producing an _______ capable of initiating and binding mineral (apatite).
- Cells
- Organic matrix
The components of hydroxyapatite, ________, are supplied via blood vessels.
calcium and phosphate
Cells thus have the cytologic features of cells that actively ______ and _____ protein.
synthesize and secrete
Mineralization in the connective hard tissues entails an ______ mechanism involving a cell-derived _______ and the control of spontaneous _________ from supersaturated tissue fluids by SCPP proteins (non-collagenous).
- initial nucleation
- matrix vesicle
- mineral precipitation
After initial nucleation, further mineralization is achieved in relation to the _______ and spread of mineral within and between fibrils.
collagen fiber
In enamel, mineralization initiates in relation to _________ of dentin and ________ from the mineralization front.
- preexisting apatite crystals
- enamel matrix proteins
