bone grafts and implantology Flashcards
Name the 4 causes of bone loss
Congenital
Traumatic
Pathology
Natural
What are the 4 types of bone graft?
Autogenous - derived from patients own bone
Xenograft - derived from a different species, typically animals
Allograft - derived from a human donor that is not the patient
Alloplastic - composed of synthetic materials
Where are autogenous bone grafts often taken from?
Intra-oral - chin, ramus, tuberosity, coronoid process
Extra-oral - iliac crest in hip and calvarium (top of skull)
What is often used for xenograft?
Deproteinised bone matrix (Bio-Oss)
What are the principles of grafting?
Osteoconduction - the concept of scaffold that supports the bone forming cells
Osteoinduction - osteogenesis is induced through the recruitment of immature cells (UMC) for bone formation
Name 4 local sites used for bone grafts
Chin
Ramus
Tuberosity
Coronoid process
Name 2 distant sites used for bone grafts
Iliac crest - most common donor site
Calvarium
What is Bio-Oss used for?
To minimise resorption
What is a bone mill used for?
Crushes bone into multiple small pieces so it can be used as a putty into areas of defect
What is applied after Bio-Oss?
Guided tissue regeneration membrane
What is an interpositional graft?
Bone graft applied between the inner and outer cortex to increase bone width
What does the site of bone graft depend on?
Patient preference
Availability of bone based on CBCT
Position of mental foramen and inferior alveolar nerve
Size of bone needed
What process do you want to happen after placing an implant?
Osteointegration
What is distraction osteogenesis?
Cutting the bone (osteotomy), separating it to create a gap and then stretching the soft tissue to form bone from within
What is nerve lateralisation?
Putting a suture around the inferior alveolar nerve and moving it laterally so an implant can be placed without any damage to the nerve
What are the steps of distraction osteogenesis?
Osteotomy
Latency - waiting for inflammatory cells to come into the area and for soft tissue healing
Distraction (lengthening)
Consolidation - leave device in to hold bone in place
Remodelling
How is lengthening carried out in distraction osteogenesis?
Using a device, a key is turned so that there is 1mm movement per day, 0.5mm in the morning, 0.5mm in the afternoon
The vector of movement needs to be considered ie - vertically, buccally or lingually
Why is 1mm the max movement per day in distraction osteogenesis?
Any more would result in fibrous healing
What are the 4 indications for zygomatic implants?
Severe maxillary atrophy
Sinus pneumatization (increase in volume)
Avoids harvesting of bone graft
Hemimaxillectomy
What is Bone Morphogenic Protein (BMPs)? and how does it work?
Active osteoinductive factors, extra-cellular protein that is stored in bone matrix
Contains cytokines 15BMP, BMP2, BMP4 and BMP7 to induce bone formation
Converts UMCs into osteoblasts, stimulating angiogenesis
