OMFS - Implantology

Question 1

What are the causes of bone loss? (4)

Answer 1

1. Congenital e.g. cleft lip and palate or hypodontia
2. Traumatic
3. Pathology e.g. infection, tumour, dysplasia
4. Natural – aging process

Question 2

List and describe the 5 types of bone grafts.

Answer 2

• Autogenous – graft harvested from the same patient
• Intra-oral: chin (common), ramus, tuberosity, coronoid process
• Extra-oral: hip and calvarium
• Xenograft – graft harvested from a different species e.g. bovine bone
• Allograft – harvested from the same species e.g. cadaveric
• Alloplastic –Natural sources and synthetic materials (proplast, HA,TCP,TCS)
• Bone bioengineering
• Growth factors e.g. bone morphogenic protein (BMP)

Question 3

What ate the 2 main principles of bone grafting - define.

Answer 3

1. Osteoconduction = provides the scaffold only that supports the bone forming cells
2. Osteoinduction = osteogenesis is induced through the recruitment of UMC (undifferentiated mesenchymal cells) for bone formation

Question 4

Define an onlay bone graft.

Answer 4

graft goes on top of the bone

Question 5

Define an interpositional bone graft.

Answer 5

graft goes between 2 sections of bone = used to increase the width

Question 6

What is a sinus lift bone graft? provide an example of when this would be used.

Answer 6

where the sinus lining is lifted and the bone graft is placed beneath
- to gain bone height for an implant

Question 7

List ridge augmentation procedures for areas deficient bone within the mandible/maxilla. (4)

Answer 7

Bone graft - onlay, inter-positional
sinus lift
IDN retraction/lateralisation
zygomatic implants

Question 8

List the 2 types of autogenous bone grafts.

Answer 8

(graft harvested from the same patient)

• Intra-oral: chin (common), ramus, tuberosity, coronoid process
• Extra-oral: hip and calvarium

Question 9

Where are xenografts usually sourced from?

Answer 9

bovine bone

Question 10

When is IDN lateralisation/retraction used?

Answer 10

During implant placement when there is resorption of the mandibular alveolar ridge (insufficient ridge height and width) and the IDN is superficial - need to retract the nerve laterally to place implants and then sit the nerve back in place once the implants are in situ

Question 11

What is alveolar distraction?

Answer 11

Lengthening the bone without the use of grafts

Question 12

Describe the process of alveolar distraction. (4)

Answer 12

1. Osteotomy– cutting away the the bone
2. Wait until a blood clot forms at this site
3. Allow callus (soft bone) to form at this site – callus replaces the blood clot
4. Place the distractor at the site and Lengthen the distractor adn therefore the bone sections 1mm per day
   = gradual lengthening

Question 13

What are the indications fr using zygomatic implants? (4)

Answer 13

• Severe maxillary atrophy
• Sinus pneumatisation
• Avoid harvesting bone grafts
• Hemimaxillectomy (no maxilla)

Question 14

What are bone morphogenic proteins used for?

Answer 14

Convert immature cells (UMCs) into osteoblasts = stimulates osteogenesis