IMPLANTS

Question 1

What are surgical space requirements for implant placement?

Answer 1

1.5mm from adjacent tooth
3mm from adjacent implant
1mm buccal/lingual bone
*2mm of buccal bone in esthetic zone for emergence profile and prevention of buccal bone loss
3mm below gingival margin for good emergence profile
2mm above IAN
5mm anterior to mental foramen to prevent mental loop

Question 2

Describe type of bone

Answer 2

Type 1. Predominantly cortical bone with minimal cancellous (anterior mandible)
Type 2. Thick cortical bone with dense cancellous (posterior mandible, anterior maxilla)
Type 3. Thin cortical bone with dense cancellous (maxilla)
Type 4. Predominantly cancellous bone (posterior maxilla)

Question 3

Considerations in bone quality type 1

Answer 3

Overheating due to dense thick cortical bone

Tapping of bone to facilitate implant placement

Question 4

Considerations in type 4 bone

Answer 4

Has lower success rate due to poor bone quality
Osteotome technique to compress denser bone laterally
Consider underprep

Question 5

Types of bone loss

Answer 5

Cawood and howell classification

1. Dentate alveolus
2. Immediate post extraction
3. Well rounded ridge with adequate bone height and width
4. Knife-edged ridge with adequate height but inadequate width
5. Inadequate bone height and width
6. Depressed ridge with loss of basal bone

Question 6

Ridge augmentation techniques

Answer 6

1) Onlay graft
2) Inlay graft including ridge split, sandwhich osteotomy, socket preservation, le fort 1 downgrafting
3) GBR with membrane or ti-mesh
4) alveolar distraction osteogenesis

Question 7

Types of bone graft materials

Answer 7

Autografts (osteogenic, osteoconductive, osteoinductive)
Allografts (osteoconductive)
Xenografts (osteoconductive)
Alloplasts (osteoconductive, osteoinductive)

Question 8

Intraoral Harvest site of autografts advantages and disadvantages

Answer 8

I/O harvest is
Easy to harvest
Local morbidity

Ramus -
cortical bone 3x3cm
cancellous bone 2.5cc
Disadv. Nerve injury. Minimal cancellous bone

Symphysis
cortical 2x1cm
cancellous 4.5cc
Disadv. Anterior teeth paraesthesia (mental nerve injury). Depression over chin. Chin ptosis.

Question 9

Conditions that risks failing autogenous bone grafts

Answer 9

1. Anterior mandible
2. Large defect >6cm
3. Inadequate soft tissue closure
4. Prior radiation

Question 10

AIBG risks

Answer 10

Hematoma - bone bleeding
Injury to LCFN causing sensory disturbance to lateral thigh
Gait disturbance due to tensor fascia lata stripping
Avulsion of ASIS
Inguinal hernia
Peritoneal perforation medially causing paralytic ileus

Question 11

Sinus lifts technique

Answer 11

Lateral wall approach (opened sinus lift)
Internal lift (closed sinus lift)

Question 12

Lateral wall approach indication & contraindication

Answer 12

Indication:
Lifting >3mm 
When alveolar height is <3mm 
More than 1 implant placements
When alveolar height is 3-8mm with simultaneous implant placement

Contraindication:
Sinusitis or sinus pathology

Question 13

Complications of lateral wall approach

Answer 13

Sinus perforation.
Small - allow membrane to fold over itself and cover the hole
Medium - collagen membrane to cover hole and pack with bone graft
Largeee perforation - abandon grafting and reenter after 6 months.

Question 14

Indications of internal lift

Answer 14

Lifting sinus floor maximum 2mm

Question 15

Mx of periimplantitis

Answer 15

1. Remove etiology (overload/infection)
2. Surgical exposure and debridement - remove granulation tissue with titanium instrument or plastic scaler
3. Surface decontamination - remove bacterial biofilm and decontaminate with saline/abrasive pumice/ chx/ hydrogen peroxide/ tetracycline/ laser
4. GBR - to fill osseous defect and eliminate probing depth

Question 16

Considerations in tx planning in patients on bisphosphonate tx for gbr and implant placement

Answer 16

1. Risk of mronj
2. “drug holiday” if already on long term bisphosphonates for osteoporosis (>5yrs)
3. Reinforce oral hygiene
4. Long term antibiotic against failure of graft, implants or mronj until completely healed

Question 17

Indication for internal lift as oppose to lateral window approach

Answer 17

• height of bone needed 3mm safe for internal lift without perforation
• areas of sinus floor that needs to be lift i.e adjacent implants requiring lifting
• anatomy of the sinus floor i.e wether its sloping or flat. Flat is easier to lift internally as the force exerted on the implant that pushes the floor to raise it is like generalized in whcih the implant acts a tent to hold the sinus lift. If its sloping, the same amnt of force exerted at the side where the bone is higher may increase risk of perforation
• anatomical variation like presence of septa
• sinus pathology