The oral environment and oral tissues Flashcards

1
Q

what are the four classes of dental materials

A

preventative
restorative
auxiliary
biomaterials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are examples of preventative materials

A
sealants
cements
liners and bases
glass ionomers
casein phosphopeptide
amorphous calcium phosphate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the three types of restorative materials

A

direct ( typical restoration)
indirect (crown, use of cements)
temporary (temporary crown)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

examples of direct restorative materials

A

amalgam and dental composite

goes directly into the tooth and finished intraorally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

examples of indirect restorative materials

A

these are fabricated extraorally on casts or using other means.
crowns, veneers, inlays, onlays, cement (luted)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

examples of temporary or provisional materials

A

materials used to restore teeth for a short period of time, a few days to a year, with understanding that they are to be replaces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are definitive restorations

A

restorative services that are provided to serve as final, long term treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are auxiliary materials

A

materials that are used to fabricate restorations, but do not become part of the restorations
eg. stone, waxes, impression materials, tray and mouthguard acrylic, finishing and polishing abrasives,
gypsum and phosphate-bonded investments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are biomaterials

A

any material that interacts with biological systems.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

tissue engineering

A

using biomaterials to repair, shape or direct the growth of host tissues.
eg. injection of cells, guided tissue regeneration, cell induction, scaffolds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

injection of cells method

A

stem cells are injected into the general vicinity of the site in which they are intended to propagate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

guided tissue regeneration method

A

a surgical procedure for regenerating tissue by enhancing the opportunity for one cell type to proliferate.
eg. a membrane is used to exclude unwanted cell types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

cell induction method

A

growth factors and developmental proteins are administered locally to induce progenitor cells to differentiate into desired tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

scaffold method

A

promoting new tissue formation by providing a surface and void volume that encourages the migration and proliferation of desired cell types.
typically allowed to attach and proliferate in vitro then grafted into a host site.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

three types of biomaterials as scaffolds

A

natural
ceramic or glass
polymeric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

enamel composition

A

96% inorganic material(mineralized), 1% organic, and 3% water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

dentin, cementum and bone are all composed of what type of collagen and what mineral?

A

collagen type I

Hydroxyapatite(also in enamel)

18
Q

what is enamel formed by?

A

ameloblasts.

Enamel apposition begins at the DEJ and proceeds outward towards the surface of the tooth

19
Q

enamel composition structurally

A
  • made of long hexagonal crystals that span the entire enamel thickness (40 nm wide)
  • the crystals are then packed into enamel rods or prisms that are 5 microns across
  • about 100 crystals needs to span diameter of prism. visible after etching
20
Q

why is the protein coat important for enamel

A

increases the toughness

21
Q

what are the interfaces between prisms called?

A

inter-rod enamel
contain, organic components of enamel, allow flow of water and ions.
-known as prism sheaths

22
Q

what kind of acid is the etch

A

phosphoric acid and it dissolves the enamel crystals in each prism

23
Q

type I enamel etching

A

prism core is preferentially etched

24
Q

type II enamel etching

A

the prism periphery is preferentially etched

25
Q

type III enamel etching

A

results in a uniform or mixed pattern of etching

26
Q

T/F there is a difference in bond strength between the types of etching?

A

false, no difference in bond strength has been established

27
Q

what type of bond does the bonding agent make with the enamel after etching has roughened the surface of the enamel making it look frosty?

A

micromechanical bond

28
Q

is the enamel near the DEJ prismatic or aprismatic?

A

aprismatic, this makes it harder to etch

29
Q

where is fluoride concentration highest in enamel?

A

higher in the subsurface making it harder to etch deeper into the enamel

30
Q

with hydroxyapatite what commonly displaces the Calcium, phosphate and hydroxyl groups seen in enamel and dentin?

A

calcium: sodium and magnesium
phosphate: carbonate
hydroxyl: fluoride (most important)

31
Q

what is hydorxyapatite called when fluoride has replace the hydroxy group?

A

fluoroapatite, which is stronger and less soluble in acids.

32
Q

what type of cells make dentin and where are they found?

A

odontoblasts, found on the outer wall of the pulp immediately medial to the advancing wall of dentin.

33
Q

what is a distinct feature of dentin?

A

tubules created by odontoblast moving in from the DEJ .

34
Q

Composition of dentin

A

50% carbonate rich, calcium-deficient apatite
30% organic material, primarily type 1 collagen
20% fluid

35
Q

what is peritubular or intratubular dentin?

A

the lumen of the tubules and is highly mineralized apatite crystals and little to no organic collagen

36
Q

what is intertubular dentin

A

the stuff between the tubules, and consists of type I collagen matrix reinforced by apatite.

37
Q

where is tubular density most dense?

A

near the pulp

38
Q

what are the 4 types of dentin?

A
  • Primary: dentin formed by odontoblasts before tooth eruption
  • Secondary: dentin formed by odontoblasts after tooth erruption
  • Tertiary: reparative dentin that forms quickly in response to trauma. *only found under dentinal tubules that have been exposed to trauma, at the outer pulpal wall
  • Transparent or sclerotic: a type of tertiary dentin that develops following trauma, tubules are partially occluded with mineral.
39
Q

what does acid etching do in dentin?

A

clears the debris from the smear layer and alters the external lumen of the tubules allowing better infiltration by bonding agents.
**peritubular dentin is preferentially removed since is has no organic component thus widening the tubule creating a funnel shape.

40
Q

why is transparent dentin hard to bond to?

A

because of the plugs formed by the minerals from the trauma, etching doesn’t always remove the plug thus making it not as permeable to the bonding agent.

41
Q

what is another important component of etching other than widening the tubules and removing the smear layer?

A

removes the mineralized component of intertubular dentin leaving a network of collagen fibrils.
This allows for the micromechanical basis for dentin bonding.

42
Q

why is dental conditioning important?

A

if you allow the dentin to become dry to collagen matrix flattens and the tubules shrink, making bonding more difficult.