Calcium sulfate bone grafts - 120 Years of Research

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Calcium sulfate bone grafts - 120 Years of Research

  1. 1. Calcium sulfate 120 years of researchDr. Amir KraitzerPh.D, MBA
  2. 2. “Simplicity is not an objective in art,but one achieves simplicity despite onesself by entering into the real senseof things”Constantine Brancusi Brancusi - The Newborn in the Museum of Modern Art, New York
  3. 3. Agenda
  4. 4. History of Calcium sulfate Bassanite9,000 year old traces in Mesopotamia5,000 year old remnants in ancientEgyptian pyramids1700‘s–Henry the 8th, king of France,orders covering all wooden walls withplaster
  5. 5. Calcium sulfate ApplicationsConstructionsArtAgricultureFood and BeverageCosmetics 19th century plasterwork from House of Borujerdies in Kashan, Iran
  6. 6. Calcium sulfate in Medicine  Pharmaceuticals  Medical devices  External Plaster casts  Internal (Orthopedics, Dental, Spine, Osteoporosis, tumor, trauma)Upper Right Mirzayan et al. 2001Arm (61F) Implantation At 3 months At 5 months
  7. 7. Agenda
  8. 8. Bone Healing Mechanisms Bone is the only tissue capable of regenerating itself completely The degree of regeneration depends on the mechanism of bone healingRepair RegenerationFormation of a regeneration is Bone new tissue the preferred of tissue having Formation mechanismdifferent than original complete in terms of bone bone similar structure andto healing leading higher volume of new formed bone of original bone composition Composition: Composition: Graft High amount of New Voids Formed Bone Fibrotic tissue Blood vessels Low amount of New Formed Bone
  9. 9. Agenda
  10. 10. Bone graft requirements(1) Osteoconductive  Mechanical support for cell migration and differentiation  Interconnected porous system to allow cell and protein infiltration(2) Bioresorbable(2) Osteoinductive  Resorbs completely in the rate of new bone formation  Contain GF offering stimulation towards osteoblastic differentiation(3) Bioactive and encourage migration of osteoprogenitor cells Biologically recruit(3) Osteogenic the cycle required for new bone formation Chemically activates  Contains living cells within the graft to form new bone
  11. 11. Bioactive properties Platelets are a natural source of growth factors Platelet infiltration is allowed by the microporosity of the graft during wound healing A Bioactive graft would activate the platelets Activated platelets release GF such as PDGF, and BMPs These GFs stimulate bone formation and angiogenesis
  12. 12. Temporary Scaffolding PropertiesVolume Graft resorption Week 12 Woven Bone Lamellar Bone Partial volume Pores (400 m) allow cell migration and angiogenesis First 4 weeks Entire volume Pores (100 m) allow growth Bone Growth factors infiltration Week 20 further Complete graft resorption 4 16 Time (weeks)
  13. 13. Slow Graft resorptionVolume Graft resorption Bone Growth50% Mechanically interferes bone formation Reduce GF and cell infiltration 4 16 Time (weeks)
  14. 14. Fast Graft resorptionVolume Graft resorption50% Reduce graft stability and Bone Growth amount of new bone formed Particle migration increase inflammation 4 16 Time (weeks)
  15. 15. Ideal synthetic graft Totally replaced by natural bone Scaffolding properties • Resorb in a rate equivalent to bone growth • Micro and macro structure for GF infiltration and cell migration Bioactive properties
  16. 16. Agenda
  17. 17. Calcium Sulfate -Literature Peltier Alderman Peltier 1960 - Rapid healing and lack of significant host Bell response. Ebourg & biou Scarano Shaffer & Apps Ricci Horowitz Hauptli Pecora Silveira and Mazor Ricci (2000) Kovacevic – CS dissolution forms a Intini Strocchi mineralised, HA-like latticework an Pecora (1997) - CS does not act simply asOrsini inert filler, but Cotzee Kelly it play a role in osteogenesis Nielscn Sottosanti Yu Berner MacNeill Coetzee (1980) – CS promotes osteogenic Wilkins Nystrom Petrova Edburg activity, stimulating bone growth in contact with bone or Kofmann Nordmann Cunningham periosteum DreesmanDreesman successfully treated tuberculous bone cavities using CS 1892 1920s 1930s 1940s 1950s 1960s 1970s 1980s 1990s 2000s 2010
  18. 18. CS Material Properties CS composition • Dihydrate- CaSO4 · 2H2O • Hemihydrate- CaSO4 · 0.5H2O • Anhydrate- CaSO4 Setting • Hemihydrate sets into Dihydrate in 15-20 Minutes • Slight exothermic reaction pH • 7.3 Mechanical properties • 10 -20MPa
  19. 19. CS Resorption propertiesVolume Maintains scaffolding properties between 4–10 weeks Woven Bone Lamellar Bone Graft Bone Growth 4 10 Time (weeks)
  20. 20. CS Resorption mechanism CS dissolves by surface erosion forming hydroxyapatite bone like structure HA HA CS CS CS time Three dissolution mechanisms:  Dissolution by hydrolysis  Enzymatic lysis by low pH  Osteoclasts and osteoblasts
  21. 21. CS Resorption mechanism 100μm Bar CS cement implanted in a rabbit 2 weeks post implantation Apatite precipitate Rings of precipitated apatite are formed in morphology and composition similar to bone
  22. 22. CS Biological Properties Both material and its degradation products are biocompatible Cells are able to migrate over CS Prevents soft tissue in-growth Human osteoblast over CS in late stage of mitosisIncrease rates of vital bone growth
  23. 23. CS Promotes Bone growth Stage 1 Stage 2 Stage 3 Infiltration Activation DifferentiationDue to the Calcium ions These GF causehygroscopic nature activate platelets to angiogenesis andof CS, platelets and release GFs osteogenic differentiationGF infiltrate through including PDGF and from mesenchymal stemits microstructure BMPs cells
  24. 24. Calcium Sulfate in practice Calcium Sulfate Calcium Sulfate Hemihydrate Dihydrate Good handling Has granular properties Cementable Non cementable Setting is retarded by proteins, blood and saliva Rapid resorption User sensitive
  25. 25. Sub- Optimal settingCalcium sulfate Hemihydrate Calcium sulfate Dihydrate
  26. 26. Crystallinityand material properties Optimal setting Highly crystalline structure Good material properties Higher strength Longer Resorption
  27. 27. Questions?

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