6. implant tissue interface. Osseointegration

Question 1

Tissues of healed implant site

Answer 1

• Edentulous ridge covered with masticatory mucosa-2-3mm thick
• Masticatory mucosa covered w/ keratinised epithelium
• Outer cortical plates lamellar bone and enclose cancellous bone
• Bone marrow very vascular

-masticatory mucosa has connective tissue rich in collagen and fibroblasts firmly attached to bone
-Cancellous bone contains trabecullae of lamellar bone embedded in bone marrow
-Bone marrow contains adipocytes and pluri-potent mesenchymal cells as well

Question 2

Types of implant systems

Answer 2

• Subperiosteal implants
• Endosseous implants with fibrous encapsulation
• Endosseous implants with direct bone contact(osseointergrated)

Question 3

Important for osseointergration

Answer 3

Primary stability

Question 4

Less traumatic surgical procedure at implant site results in

Answer 4

Faster formation of healthy bone at implant surface

Question 5

Bone healing in cortical and Cancellous(spongy) components

Answer 5

1. Cortical- Mineralised tissue must be removed before new bone can form
2. Cancellous
   * Clot formation
   * Coagulum gradually resorbed and replaced w/ granulation tissue
   * Ingrowth of vessels, leukocytes and mesenchymal cells
   * Granulation tissue replaced with provisional connective tissue(provisional matrix) and eventually osteoid
   * Deposition of hydroxyapetite crystals in osteoid
   * Immature woven bone formed

Mesenychmal cells migrate from surrounding marrow and aid in transformation of granulation tissue

Question 6

Process of osseointegration

Answer 6

• Clot formation
• Ingrowth of vessels and migration of leukocytes and mesenychmal cells
• Granulation tissue replaced with provisional matrix
• Fibroplasia and angiogenesis starts
• New bone formation seen in first week of healing
• Newly formed woven bone projects from lateral wall of cut bony bed
• New bone formation also on implant surface
• In following weeks trabeculae of woven bone replaced with mature bone

-Clot formation stumulated by thrombocytes->signals->fibroblasts
-Provisional matrix rich in vessels, mesenchymal cells and fibres

Question 7

Newly formed woven bone projects from lateral wall of cut bony bed

Answer 7

• Distance osteogenesis/ Appositional bone formation

will be replaced by mature bone by remodelling

Question 8

New bone formation on implant surface

Answer 8

Contact osteogenesis

at a distance from parent bone