Dental Orofacial implants and Tissue Engineering Flashcards Preview

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Flashcards in Dental Orofacial implants and Tissue Engineering Deck (53)
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1
Q

what is a endosseous implant

A

sits in the bone

most common

2
Q

what is a subperiosteal implant

A

rare, but used in cases of atrophic bone/ site on top of the bone

3
Q

what is a transosteal implant

A

uncommon, higher failure rates. Transverses the entire mandible, not used on the maxilla
Disadvantage: complete facial butchery

4
Q

what is the alveolar process?

A

ridge on surface of mandible/maxilla wherein dwell teeth

5
Q

basal bone

A

bone underlying the alveolar process

6
Q

alveolar bone proper

A

-compact bone (cribriform plate, lamina dura)

7
Q

supporting alveolar bone

A

both compact and trabecular bone

  • cortical plates: compact bone component
  • central spongiosa: trabecular bone component
8
Q

what is critical for maintaining bone density?

A

loading

9
Q

loss of alveolar bone in edentulous patients results in having what type of bone?

A

basal bone

10
Q

what is osseointegration?

A

deposition of bone in close apposition to implant surface

  • mediated by mesenchymal progenitor cells
  • provides mechanical stability of implant and a tight seal
11
Q

what is the key first step to osseointegration?

A

hole fills with a clot, which is then converted to a highly cellular granulation tissue

12
Q

what does the granulation tissue become over time?

A

bone tisuse

13
Q

when a formation of fibrous soft tissue(collagen) around an implant occurs what is this called? and is it good or bad?

A

fibrous encapsulation

  • bad news, results in poor stability of implant
  • can result from peri-implantitis
14
Q

what are the mechanical forces acting on implants?

A

tensile, compressive, and shear forces

15
Q

what must bone experience to keep from resorbing?

A

strain

16
Q

why are ceramics a bad choice for implants?

A

tend to be stiff and do not transfer adequate strain to surrounding bone, resulting in stress shielding

17
Q

why is titanium a better choice for implants?

A

more elastic (lower elastic modulus) and transfers some strain to surrounding bone

18
Q

what must an implant material have to be successful?

A

structurally sound but also must have mechanical properties which are physiologically compatible

19
Q

if the elastic modulus is too high what happens to the bone?

A

there is less transfer of force to bone and thus lower bone loading

20
Q

when is bone strongest?

A

when it is compressed

21
Q

when is bone weak?

A

under tensile forces

22
Q

when is bone weakest?

A

when it is subject to shear forces

23
Q

why is a smooth implant a bad idea?

A

because the force on the bone will almost be completely shear

24
Q

why does threading an implant make it much better than a smooth one?

A

it engages bone in compression where it is strongest
-interlocking also provides much better transfer of load to bone(less resorption) and increased surface area for attachement

25
Q

does increasing the length of an implant make it better worse? What is a minimal advantage?

A

worse because the increased surface area leads to less load on the bone
-most force happens at the coronal portion of the implant. Anatomy and heating

26
Q

does increasing the width make an implant better or worse?

A

once again you are increasing the surface area thus decreasing the stress as well as stress shielding due to the more stiff wide implant

27
Q

what are the properties of titanium that make it the most common material for dental implants?

A
elastic modulus
strength
non immunogenic
low corrosion (oxide layer)
biocompatible (non toxic)
-also it can be modified in a large number of ways
28
Q

what is the oxide layer of titanium?

A

the outer layer that has interacted with air and what biological systems interact with

29
Q

what is the purpose of coating the implant or roughening/etching?

A

enhancing osseointegration by:

  • osteoblast differentiation/migration
  • improving mechanical interlocking with bone tissue, providing better loading characterisitics
30
Q

Implant surface chemistry modification

A
  • refers to increasing oxide layer

- titanium oxide layer favors protein absorption

31
Q

what does hydroxylation do?

A

increases hydrophilicity (wettability)

32
Q

what does anodization do?

A

increases oxide layer thickness

33
Q

ceramic and glass coatings are bioactive but they are only as strong as what?

A

the metal -ceramic interface

34
Q

what does coating with short peptide sequences to?

A

increase cell attachment

eg: integrin, RGD cell attachment sequences, collagen, fibrin

35
Q

coating with growth factors is associated with what?

A

wound healing

36
Q

what is the survival rate of endosseous implants?

A

7 year rate of around 95%

37
Q

for implants you must have careful patient selection, what are somethings to look for in patients?

A

good bone around site

not be compromised in terms of bone healing

38
Q

what are bioactive materials?

A

materials which are designed to drive repair/ regeneration through the use of bioactive factors

39
Q

what are the three components in tissue engineering?

A

relevant cell source
biomaterial or scaffold
bioactive component to drive cell responses

40
Q

what are 4 general classifications of relevant cell sources?

A

autograft
allograft
xenograft
alloplast

41
Q

what is an autograft?

A

implanted material derived from the same individual as the implant is to be delivered into

42
Q

what is an allograft?

A

implant material derived from another individual of the same species

43
Q

what is a xenograft?

A

implanted material derived from another species

44
Q

what is an alloplast?

A

implanted material that is not derived from a living source or is synthetic (very broad category)

45
Q

what are Dental Pulp Progenitor Cells?

A

population of mesenchymal progenitors resident in the dental pulp, derived from the neural crest

46
Q

what can dental pulp progenitor cells differentiate to regenerate?

A
vasculature
mineralized tissue
soft tissue
nerves
-represent a capacity of the tooth for self repair.
47
Q

cellular vs. acelluar approaches

A

additional material containing cells vs. application of materials to existing tissues

48
Q

how do you isolate dental pulp progenitor cells (DDPCs)?

A

low cell numbers (1% of cells)
lack of single specific marker to ID cells.
DDPCs are adherent cells and will stick to tissue culture plastic

49
Q

DDPCs express high levels of what?

A

alpha 5 beta 1

50
Q

what does alpha 5 beta 1 bind to?

A

fibronecting, thus you can use fibronectin adhesion for isolation of DDPCs.

51
Q

what are some challenges to overcome in oral tissue regeneration?

A

microbial infection, inflammation, regeneration

52
Q

what is biomimetic?

A

mimicry of tissues/processes/structures that are biological.

53
Q

T/F through tissue engineering, it may be possible to manipulate the innate capacity of oral tissue to encourage REPAIR or perhaps REGENERATION?

A

true, this leads to more options for practitioners and improved outcomes for patients.