Dental Implants and Bone Augmentation

Question 1

What are the 4 parts of an implant?

Answer 1

crown
abutment screw
abutment
implant

Question 2

What are the 3 types of implant materials?

Answer 2

1. titanium alloys
2. zirconium
3. tantalum

Question 3

Who discovered Osseointegration? How did they do this?

Answer 3

P.I. Branemark from Sweden in 1952

• titanium chambers inserted in a rabbit femur became firmly fixed to the bone and could not be removed
• living bone could become so fused with the titanium oxide layer of the implant that the two could not be separated without fracture
• fractures occurred between bone and bone (not bone and implant)

Question 4

Define osseointegration

Answer 4

• a direct functional and structural connection between living bone and the surface of a load carrying implant
• a process whereby clinically asymptomatic rigid fixation of alloplastic materials is achieved and maintained in bone during functional loading

Question 5

What is the minimum bone thickness required for an implant (F-L: faciolingual)?

Answer 5

2 mm facial bone thickness

Question 6

What happens if the bone thickness is not 2 mm?

Answer 6

• increased frequency and extend of vertical bone loss
• resorption following integration which may expose implant surface (i.e., esthetic problem)

Question 7

What is the minimum bone thickness required for an implant (M-D: mesodistal)?

Answer 7

1.5 mm between implant and tooth
3 mm between implants

Question 8

What is guided bone regeneration?

Answer 8

surgical procedure that utilizes barrier membranes to mechanically exclude the undesirable soft tissues from growing into the osseous defect, allowing only osteogenic cells from the parent bone to repopulate the wound space

Question 9

What are the guided bone regeneration (GBR) principles?

Answer 9

Primary closure
Angiogenesis
Support
Stability

Question 10

What is angiogenesis?

Answer 10

decortication and regional acceleratory phenomenon (RAP)
- allows bleeding from marrow spaces, quicker revascularization
- vascular ingrowth may promote neogenic bone formation
- increases regional accelerated phenomeonon (RAP)
- improves graft union

Question 11

Describe support/membrane fixation

Answer 11

• micro-motion soft tissue layer under the membrane
• inadequate stabilization, loss of wound space-fibrous encapsulation
• suturing of the flap can displace the graft
• tacking membrane reduces graft collapse by 50% following suturing
• fixation increases grafting success

Question 12

What are the recommended support/membrane fixation systems?

Answer 12

1. meisinger master pin
2. self tapping miniscrews (pro-fix osteogenics)

Question 13

What is osteoconduction?

Answer 13

provide space and substratum for the cellular and biomechanical events progressing to bone formation

Question 14

What is osteogenesis?

Answer 14

direct transfer of vital cells to the area that will regenerate new bone

Question 15

What is the problem with autograft bone grafts?

Answer 15

because its from yourself you will see lots of resorption

-35-51% horizontal resorption
- 81% volume loss over 2 years

Question 16

What happens if you add autogenous bone to bone substitutes?

Answer 16

• produces greater gain
• shows less graft volume reduction in the longer term

Question 17

Bone grafts release 43 different growth factors including

Answer 17

• TGFB1 and 2
• osteoblast stimulating factor I
• BMP

Question 18

What are the types of defect characteristics?

Answer 18

1. horizontal
2. vertical
3. combinations (both horizontal and vertical
4. intrabony defect (in the bone)
5. extrabony defect (outside the bone)

Question 19

What are the horizontal expectations for particulate bone grafts (GBR), autogenous bone grafts, and ridge splits?

Answer 19

Question 20

Describe the defect characteristic

Answer 20

1. bone graft heals from outside in
2. regenerative capacity comes from the existing bony walls
3. 4 wall defect = rapid bone formation
4. 1 wall defect = slow bone formation
5. success = volume stability and time

Question 21

What do you do if you have a 2-3 wall small defect?

Answer 21

fixation not always necessary, collagen membrane

Question 22

What do you do if you have a large defect?

Answer 22

membrane fixation, consider non-resorbable membrane, consider growth factors, 50:50 AB:DBBM

Question 23

Describe d-PTFE membrane

Answer 23

*nonresorpable

• dense polytetrafluoroethylene (teflon)
• pore size <0.3 micrometers, bacterial size is 1-5 micrometers
• can be left exposed to oral environment
• when fixed, offers excellent stabilization to underlying graft

Question 24

Where is a block graft taken from?

Answer 24

symphysis, ramus/external oblique ridge

Question 25

What are the vertical augmentation options?

Answer 25

1. guided bone regeneration (GBR)
2. block/only graft
3. distraction osteogenesis
4. interpositional graft

Question 26

What are the 2 sinus elevation approaches?

Answer 26

1. vertical approach
2. lateral approach (gains more bone)

Question 27

What is the vertical sinus elevation approach?

Answer 27

uses the osteotome technique

• percussion and hyperextension of the neck can dislodge otoliths and induce vertigo
• difficult to asses membrane tears

Question 28

What is the lateral window technique?

Answer 28

• 6-9 months of healing depending on size of graft
• longer it heals, more bone available