W6 - Surgical Implantology - Tulio

Question 1

How can temp crowns be used for preprosthetic surgery

Answer 1

Different contours of temp crowns can be used to reshape soft tissues

• Correct future emergence profiles

Question 2

What are factors for planning proshetic design? (process) (5)

Answer 2

Aesthetics

Perio health

Tissue reconstruction

Support, stability, retention needs

Question 3

Strategies to achieve proper bone augmentation (5)

Answer 3

1. GBR
2. Bone block grafts
3. Distraction osteogenesis
4. Sinus lift
5. Transposition of IAN

Question 4

Absolute contraindications of implant placement

Answer 4

Recent radiotherapy pt of head/neck (angiogenesis affected, difficult to heal, fragile bone)

Question 5

Principle of GBR (4)

Answer 5

Exclude soft tissue

space maintenance

clot stabilization

Bone particles placed for regeneration

Question 6

Advantages and disadvantages of GBR

Answer 6

Pros:

Graft availability

Good for horizontal bone defects

Cons:

Decreased osteoinduction

Low predictability in vertical defects

Lack of tissue integration with titanium reinforced membranes

Question 7

What happens if an implant is placed when there is severe bone loss

Answer 7

Long implant screw

crown will appear very long

• May require pink porcelain
• Unaesthetic
• Unstable

Question 8

What are the 2 sinus lift techniques

Answer 8

Lateral technique

Transalveolar technique aka summers technique

Need at least 6mm of bone to place implant and graft for summers technique, otherwise do lateral technique

Question 9

How does smile change as you age? (3)

Answer 9

• More of lower teeth shown
• Loose collagen and tension in skin (not as elastic)
• Smile curves more downwards

Question 10

What are partial contraindications for implants? (2)

Answer 10

• Osteoporosis (fragile bone- if you drill bone it will be soft. Healing will be delayed- reduced osseointegration)
• Uncontrolled diabetes

Question 11

How to do GBR (4)

Answer 11

Perforate surface to create bleeding from base of bone

Mix bone particles

Place membrane on top to isolate soft tissues out

Suture

Question 12

What is the lateral sinus lift (4 steps)? Indication?

Answer 12

Indicated when there is pneumatisation of mx sinus

• Buccal window made in posterior mx bone
• Careful elevation of sinus epithelium
• Place bone graft without perforating membrane
• Wait 4-5 months and place implant

Question 13

What can happen to lip if prosthesis is too far B?

Answer 13

Lip can evert

Question 14

What factors influence whether pts condition is relative or absolute contraindication for implants?

Answer 14

Type of prosthesis

Age of patient

Location of prosthesis (ex. 16 and 26 bone is porous- avoid implant placement if pt has osteoporosis)

Question 15

What is the purpose of having titanium reinforced skeleton for GBR?

Answer 15

Maintains size and shape to prevent tissue shrinkage

Question 16

What can happen if membrane is not placed in bone defect?

Answer 16

Soft tissue occupies defect and collapses

More fibour tissue rather than bone

Question 17

What are the types of membranes? (3)

Answer 17

Natural polymer

Synthetic polymer

Metal

Question 18

What are bioactive molecules? Downside?

Answer 18

BMP-2

Triggers bone formation and increases angiogenesis

• Expensive

Question 19

What are hemiderivates? (graft) Challenge?

Answer 19

Autologous growth factors obtained from blood after centrifugation (ex. PRF)

• can make graft more biocompatible and triggers more bone formation

Challenge: biological variability, difficulty tailoriing degradation rate

Question 20

What is the basic concept of bone tissue engineering

Answer 20

Relies on combination of cells, engineering materials (scaffold) and suitable biochemical factors to repair damaged tissues and organs

Question 21

Question 22

What can scaffolds be made of?

Answer 22

Bioceramics: Bi-calcium Phosphate (BCP), hydroxyapatite

Polymers:

(natural- collagen fibrin, cellulose) or Synthetic (PCL, PEG)

Then do surface modification (coat with CaPO4) to trigger bone formation

Can do this to avoid need for autogenous bone graft.

Question 23

What is the role of cells on bone tissue engineering?

Answer 23

MSC’s proliferate and differentiate into osteoblasts and fibroblasts

Question 24

What are autologous bone blocks used for?

Answer 24

Can be used for large defects (rather than using particular bone graft)

Question 25

What are tissue bank bone block grafts? (2)

Answer 25

• Sterilized and preserved
• Retains osteoconductive properties

Question 26

What is the issue with screws being placed on tissue bank bone blocks?

Answer 26

More bone is placed than necessary as the bone resorbs substantially

Bone graft is screwed into place and will protrude out of bone block graft and can impinge on soft tissues as bone resorbs

Question 27

What is transalveolar/summer sinus lift?

Answer 27

Used when there is some height of bone but not enough

• Drill across alveolus from top
• Push membrane of sinus up
• Place bone graft
• Place implant

Question 28

Example of cells used in tissue engineering (3)

Answer 28

MSC

Osteoblast

Endothelial progenitor cell

Question 29

What is the role of biochemical factors in bone tissue engineering

Answer 29

Stimulate cellular response

Differentiate MSCs in bone cells lineage

Angiogenesis

Ex. BMP-2

Question 30

Advantages of Bone Tissue engineering (4)

Answer 30

Biocompatibility

Space maintenance

Good for Vertical bone defects

Good tissue integration

Question 31

Challenges of Bone tissue engineering

Answer 31

Tailoring degradation rate

Soft tissue engineering