Week 6 Tulio- Surgical Implantology Flashcards
What are the types of implant prostheses?
- Unitary implant
- Implant supported bridge
- Implant supported hybrid prosthesis
- Overdentures
How does smile change as you age?
- More of lower teeth shown
- Loose collagen and tension in skin- not as flexible and elastic
- Smile is curved more downwards
How are temp crowns used for preprosthetic surgery?
Placement of temp crowns can shape soft tissues to correct future emergence profiles (long process)
What are factors for planning prosthetic design?
- Aesthetics
- Periodontal health
- Tissue reconstruction
- Support, stability and retention needs
What are current strategies to achieve bone augmentation?
- Guided bone regeneration
- Bone block grafts
- Distraction osteogenesis
- Sinus lift
- Transposition of IAN
What is an absolute CI for implants?
Recent radiotherapy pt of head/neck (angiogenesis affected, difficult to heal, fragile bone)
What are partial CI for implants?
- Osteoporosis (fragile bone- if you drill bone it will be soft. Healing will be delayed- reduced osseointegration)
- Uncontrolled diabetes
What is the principle of guided bone regeneration?
Perforate surface to create bleeding from base of bone. Mix bone particle and on top of that, place membrane. This will create isolation from soft tissue to encourage more bone formation.
Used more in horizontal bone defects
What happens to implant crown if there is bone loss and implant is place?
Crown will appear very long
4 types of grafts + example of each?
- Autograft: pts own tissue
- Allograft: freeze dried bone- other human
- Xenograft: freeze dried bone- bovine
- Alloplast: Bio-glas, hydroxyapatite, calcium phosphate
How is distraction osteogenesis used in implants?
Activate distractor device on bone defect to fill the defect (need the vector of destruction in the correct direction so bone forms in correct location)
What are 2 techniques for sinus lift?
- Transalveolar approach (need 6mm of bone to place implant and graft otherwise need to do lateral approach)
- Lateral
What is principle of lateral sinus lift?
Used when there is pneumatisation of maxillary sinus.
- Buccal window made in the posterior maxillary bone,
- Careful elevation of the sinus epithelium
- Place bone graft (don’t perforate membrane)
- Wait 4-5 months and place implant
What can happen to lip if prosthesis is too far B?
Lip can evert
What factors influence whether pts condition is relative or absolute contraindication for implants?
- Type of prosthesis
- Age of patient
- Location of prosthesis (16, 26 bone is porous and not dense- avoid implant placement if pt has osteoporosis)
What is the purpose of having titanium reinforced skeleton?
Maintains size and shape to prevent tissue shrinkage
What can happen if membrane is not placed in bone defect?
Soft tissue occupies defect and collapses. More fibrous tissue rather than bone
What are the types of membranes?
- Natural polymer (collagen- human, bovine, porcine)
- Synthetic polymer (PCL, PTFE)
- Metal (titanium)
What are bioactive molecules?
BMP-2 triggers bone formation and increases angiogenesis (expensive)
What are hemoderivates?
Autologous growth factors obtained from blood after centrifugation e.g. PRF (platelet rich fibrin)
- Can make bone graft more biocompatible and trigger more bone formation
What is the basic concept of bone tissue engineering?
Relies on combination of cells, engineering materials (scaffold) and suitable biochemical factors to repair damaged tissues and organs
What can scaffolds be made of for bone engineering?
- Bioceramic: hydroxyapatite, bi-calcium phosphate
- Natural polymers: collagen fibrin
- Synthetic polymers: PCL, polylactic/polyglycolic acid
Then do surface modification (calcium phosphate) to trigger bone formation
Can do this to avoid need for autogenous bone graft.
What is the role of cells in bone tissue engineering?
MSC’s proliferate and differentiate into osteoblasts and fibroblasts
What are autologous bone blocks used for?
Can be used for large defects (rather than using particular bone graft)
What are tissue bank bone block grafts?
- Sterilized and preserved
- Retains osteoconductive properties
What is the issue with screws being placed on tissue bank bone blocks?
More bone is placed than necessary as the bone resorbs substantially. Bone graft is screwed into place and will protrude out of bone block graft and can impinge on soft tissues as bone resorbs
What is transalveolar/summer sinus lift?
Used when there is some height of bone but not enough
- Drill across alveolus from top
- Push membrane of sinus up
- Place bone graft
- Place implant
What is the role of biochemical factors in bone tissue engineering + examples?
Stimulate cell response, differentiate MSC’s and inc blood vessel formation
- BMP-2
- Insulin like growth factor (IGF)
What are advantages of bone tissue engineering?
- Biocompatible
- Space maintenance
- Tissue integration
- Suitable for vertical defects
