54. Implantation in the subantral bone

Question 1

Four methods to increase rate of bone formation and augment bone volume in subantral bone

Answer 1

• Osteoconduction=>bone growth occurs on a surface
• Distraction Osteogenesis=>Surgically lengthens bone
• Guided Tissue Regeneration (GTR)=>directs growth of new bone and tissue
• Osteoinduction=>osteogenesis induced

Question 2

How bone defects classified based on morphology

Answer 2

• Intra-alveolar defects
• Horizontal defects
• Vertical defects

Question 3

Type of bone defect is most frequent and what does it include

Answer 3

• Horizontal bone defects=>
• Dehiscences
• Fenestration

Question 4

How horizontal bone augmentation managed in cases of minimal and significant deficiencies

Answer 4

• Minimal Deficiencies=>
• Dehiscence or fenestrations of implant surface during implant placement
• Significant Deficiencies=>Implant w/ more than one axial surface exposed or when significant horizontal deficiency=>
• Reconstruction of bone necessary before implant placement

Question 5

Recommended solution for managing large horizontal deficiencies in bone when implant placement would result in its exposure

Answer 5

• Reconstruct bone first=>
• Lateral ridge augmentation=>autograft from retromolar or symphysis area=>
• Covered by membrane
• Reopening for membrane removal and implant placement after 7-13 months

Question 6

Indications of particulate bone grafts

Answer 6

• In defects w/ multiple osseous walls=>
• Will contain graft
• Dehiscence or fenestration defects when implants placed during bone augmentation

Question 7

Advantages of particulate bone grafts

Answer 7

• Smaller pieces of bone demonstrate=>
• Rapid ingrowth of blood vessels
• Larger osteoconduction surface and more exposure to osteoinductive growth factors
• Easier biological remodeling

Question 8

Monocortical block graft, and when it is indicated

Answer 8

• Horizontal deficiencies=>challenging to reconstruct w/ particulate grafts
• Disadvantages=>Biologic limitation in revascularizing large bone blocks

Question 9

How vertical bone defects managed

Answer 9

• Vertical ridge augmentation=>
• Autogenous, particulate or block bone grafts, or bone substitute materials combined w/ PTFE membranes
• Guided Bone Regeneration (GBR)=>
• Successful for vertical bone augmentation up to 3 mm=>
• w/ membrane–blood clot combination
• Titanium-reinforced (TR) membranes can be used without supportive bone substrates

Question 10

Distraction osteogenesis

Answer 10

• Increase vertical bone height=>
• Advantage of native bone at crest and avoiding second surgical site
• Disadvantages=>
• Unidirectional limitation of devices
• Secondary bone grafting needed for extremely resorbed ridges=>
• Achieve horizontal growth