Surgical Aspects of Implants

Question 1

What is pre-implant surgery?

Answer 1

Surgery done prior to implant going in to ensure environment is suitable for implant
Usually augmentation - bone will have dissolved away and will need to be replaced

Question 2

Why do pre-implant surgery?

Answer 2

Too little bone to support implant in an acceptable position

Too much bone (rare) - ridge reduction

Question 3

Why reduce the ridge?

Answer 3

Bone of poor quality (too thin - if reduce ridge = bone gets thicker)
Additional restorative space

Question 4

Augmentation techniques?

Answer 4

Sinus lift
Block graft
Guided bone regeneration
Ridge split
Zygomatics
Use of narrow/short implants

Question 5

Types of augmentation?

Answer 5

Autograft - pinch a bit of bone (bone shaving) from somewhere else on the same patient
Allograft - get bone from someone else
Xenograft - get bone from an animal
Inorganic material - beta TCP and HAP (hydroxyapatite) (used for religious region)

Question 6

What is osseoinduction?

Answer 6

Promotes bone formation

Question 7

What is osseoconduction?

Answer 7

A scaffold

Question 8

What techniques increase the bone width?

Answer 8

Guided bone regeneration
Ridge split
Block graft
Narrow/angled implants

Question 9

What techniques increase bone height?

Answer 9

Onlay graft (still a block graft) (does not work very well)
Inlay graft
Osseodistraction
Short implants/all on 4
Zygomatic implants

Question 10

What are the principles/stages of bone augmentation?

Answer 10

Plan - Diagnostic wax up - Stents
Raise flap and distress surface (evaluate and stimulate graft site)
= angiogenesis created (new BVs created) = path for new BVs to supply new bone
= also allows graft to integrate into bone without cortical plate being in the way = osseogenesis (bone formation)

Fix graft
Leave 3-6 months for angiogenesis and osseogenesis (if larger bone regeneration = leave for longer)

Question 11

Inadequate width by a small amount - guided bone regeneration is done: what is the function of the membrane that overlies the particulate?

Answer 11

Membrane protects particulate to stabilise it and protect fibroblasts from flap passing into articulate as it is remodelled into bone

Question 12

How is guided bone regeneration done?

Answer 12

Take scrapings of bone and blood = large surface area of bone that will release cytokines and blood has inflammatory mediators = blood is osseoinductive

Question 13

Why distress the bone before placing the implant?

Answer 13

Drill before implant is in around it = decortication/distressing of bone = angiogenesis and osseogenesis

Question 14

How is dual layer guided bone regeneration completed?

Answer 14

Internal layer with bone chips = can be dissolved
External layer with scaffold which cannot be dissolved and will protect the underlying layer and blood to cause bone to form around the scaffold

Question 15

Aims of the dual layer guided bone regeneration technique?

Answer 15

Bone chip s- osseoinductive
Bone substitute - osseoconductive (prevent it being dissolved)
Absorption of bone-conditioned blood makes bone substitute osseoinductive
Membrane over top to prevent soft tissues contacting and resorbing grafted material

Question 16

Inadequate width of bone if small to moderate amount - manage with ridge split osteotomy - what is this?

Answer 16

Opening bone and making it broader

Question 17

Moderate to large amount inadequate width of bone - Buccal onlay graft - what is this?

Answer 17

Distress bone
Block graft and membrane on top
Particulate around it to help support it when it seal

Question 18

Where is bone for grafts most commonly taken from?

Answer 18

Mandibular symphysis

Mandibular ramus

Question 19

Mandibular symphysis grafts?

Answer 19

Mental nerve damage
Reduced sensitivity over chin
Scarring in buccal sulcus - fraenal tags
Chin ptosis 
Apicectomy of anteriors or necrose them by removing the blood supply

Question 20

Inadequate height of bone - occlusal onlays?

Answer 20

Large amount of bone needed from hip or rib = poor bone quality

Question 21

Inadequate heigh of bone - how to deal with localised defects?

Answer 21

Osseodistraction

Osseodistractor attached to basal bone and screwed in and expands the bone over a couple of weeks

Question 22

What can you do with inadequate bone height when risk of nerve damage?

Answer 22

Mandibular inadquate height = reposition the nerve to avoid damaging it when a bone graft needed
BUT still big risk of nerve damage