Defective ground substance and laying down of collagen, therefore not mineralized

Etiology:

• AD – Defect in biosynthesis of collagen 1
• Mutations in structural gene for collagen proteins – ie. COL1A2 – same mutation causes dentinogenesis imperfecta

Clinical:

• Bone fragility (thin bones without cortex)
• Hearing loss
• Dentinogenesis imperfecta
• Blue sclera
• Opalescent dentine
• Spine deformities
• Joint hyperextensibility

Classification:

Diagnosis:

• Histology:
  • Decreased mass of cortical and cancellous bone
  • Bone architecture immature throughout life since woven bone does not mature to lamellar bone
• DNA based sequencing test
• X-ray

Management:

• Bisphosphonates
• Extensive restoration with full crown coverage
• ENT – correct hearing loss
• Physiotherapy/ surgery – kyphoscoliosis
• Intramedullary rodding – orthopedic management