Bone and cartilage repair strategies Flashcards
4 main bone repair strategies
▪ Guided bone regeneration
▪ Biophysical effects
▪ Distraction Osteogenesis
▪ Biomolecules
6 main cartilage repair strategies
▪Chondroarthritis
▪Lavage/Debridement
▪ Cell Containing Devices
▪ Mosaicplasty
▪ Autologous Chondrocyte Transplantation (ACT)
▪ Extracorporal Strategies
4 current materials approaches to bone/cartilage reconstruction
Biomaterials( metals, ceramics, glasses, polymers)
Autografts
Allografts
Xenografts
Currently why are tissue grafts(Autografts Allografts Xenografts) better than artificial substitutes?
they contain living cells and tissue interacting substances - possess Biological Activity
Just like most materials problems what is the best thing to do, to optimize bone/cartilage repair materials? Also what 2 properties does this optimized material improve?
composite the grafts/ living host cells with artificial substitutes(metals, ceramics, glasses, polymers) in to a cell containing hybrid. these hybrids can provide physiological response and structural support.
what is bone/ cartilage engineering meant to do?
Exploit living cells to restore, maintain or enhance tissue function
definition of situ
in the natural or original position or place
Three principal methods of Bone and Cartilage Engineering?
-In situ
Tissue Regeneration
-Implantation of
Freshly Isolated
or Cultured Cells
-Implantation of a
Bone-like or Cartilage-like Tissue assembled
in vitro from cells and scaffolds
simply put how does In situ Tissue Regeneration work?
- New tissue formation is induced by specific scaffolds,
- External stimuli – stimulates body’s ability to self repair
simply put how does Implantation of
Freshly Isolated
or Cultured Cells work?
Individuals cells or cell aggregates from patient injected directly into damaged region.
simply put how does Implantation of a
Bone-like or Cartilage-like Tissue assembled
in vitro from cells and scaffolds work?
Complete three dimensional tissue is grown in vitro using autologous or donor cells within a scaffold after its reached
maturity.
2 classical bone repair strategies
-Enhancement of the local host cell population.
-Transplantation of grafted bone
what does the augmentation of the host cell population do?
- Improves healing of bone lesions (damage).
- Highly dependant on condition of the repair site.
–If soft & hard tissue are healthy – expansion of host cells is often successfully applied.
–Wound infection/ tissue necrosis /irritation – cellular augmentation of the local bone cell population will fail
what chemical stains are used to determine bone health?
Hematoxylin and eosin stain
how is bone health determined using Hematoxylin and eosin stain
- Non-viable bone as demonstrated by lack of nucleoli in
bone lacunae (L) and necrosis of bone marrow (NB). - Cultures of the marrow had no bacterial/fungal growth
How doe the membrane techniques for bone repair work in simple terms?(GBR)
Membrane Techniques are used to improve defect healing by ingrowth of local cells in the defect site
Guided bone regeneration objective and Healing pattern(mostly for facial maxilla and mandible)(GBR)
Objective: Separate Bone Tissue from the soft Tissue
Ingrowth by a barrier.
Healing pattern:
-Blood clot formation.
- Invasion by osteoprogenitor cells(stem cells in the bone that play a important role in bone repair and growth).
- Differentiation of osteoprogenitor cells into osteoblasts(bone BUILDERS)
where is Guided bone regeneration applied?(dental)(GBR)
+ Extractions - Empty tooth socket after extraction – fill with bone-inducing granulate to avoid alveolus atrophy( bone degradation)
+Periodontopathy inflammation of the tissue around the teeth, often causing shrinkage of the gums and loosening of the teeth, ligament and surrounding bone are destroyed - tooth loss
+ Sinus floor elevation - Also called sinus-lifting - thickening of the bottom wall of
the sinus, where the implant is to be placed
principles of guided bone regeneration(GBR)
-the implant is inserted in to he bone at the alveolar crest(first layer of bone that is not tooth)
-Membranes attached to the defect site – seals the
defect from tissue ingrowth of adjacent tissues.
- New bone is developed by using the membrane techniques.
does bone augmentation work very good with out any membrane techniques?(GBR)
no, it results in a mid ass state of repair
specifically what are the materials (BioOss, BioGide, BioGen, BioCollagen) used in guided bone regeneration able to fix
*Atrophied tooth-supporting structures.
* Reconstruction of bones destroyed by periodontal disease.
* Reconstruction of bones before implant treatment.
* Reconstruction of soft tissues surrounding the tooth
What are the 3 variables deciding if guided bone regeneration will work good?(GBR)
- Defect size and geometry.
- Defects repair better when there is more than two bony walls.
- Main limitation – difficult to reconstruct geometrically complex or large defect sites
4 Biophysical bone repair strategies
I. Electrical Stimulation
II. Mechanical Stimulation – Distraction osteogenesis, ultrasound stimulation, fracture activation
III. Ultra sound adjacent structures (ligament, joints, muscle) – major impact on the resultant biophysical signal at the desired effector site.
IV. Distraction Osteogenesis Bones are gradually moved from each other – new bone grows within the gap. Molecular mechanisms governing the formation of new bone in interfragemental gap of
gradually distracted bone still unclear.
What does Biophysical Electrical stimulation do?
applied to a patient to enhance bone formation – the electrical stimuli can also affect other tissues
