DENTIN

• Dentin

  • Inorganic portion – 65% hydroxyapatite
  • Organic portion – 35% collagenous fibrils
  • Hydroxyapatite crystals are much smaller in dentin than in enamel
• Dentin

  • Substantia eburnea
  • Derivative of dental papilla
  • Forms the bulk and provides general shape of the tooth
  • Vital tissue
• Peritubular dentin

  1. Intratubular dentin

  2. Dentin that immediately surrounds dentinal tubules

  3. Has more mineral content than intertubular dentin
• Odontobastic processes

  1. Cytoplasmic extensions of odontoblasts

  2. Extends throughout the thickness of dentin

  3. Extends to the enamel (enamel spindles)
• Predentin


  1. Innermost portion of dentin that is not yet mineralized

  2. Located adjacent to pulp tissue

  3. Becomes mature dentin after Ca and P salts will be deposited and new predentin will be formed
• Neonatal lines


  1. Reflects the abrupt change in environment before and after birth

  2. Between prenatal dentin and postnatal dentin

  3. All primary teeth and 1st permanent molars

  4. Quality of dentin formed before birth is better than dentin matrix formed after birth
• Dentin

  • 2o teeth are much harder than 1o teeth
• Dentinal tubules


  1. Sigmoid course straight course

  2. Perpendicular to pulpal surface and to DEJ DCJ

  3. Lamina limitans – organic sheath or lining that surrounds the dentinal tubules
• Other structures related to dentin

  1. Odontoblastic processes

  2. Incremental lines of von ebner

  3. Contour lines of owen

  4. Neonatal lines

  5. Interglobular dentin

  6. Tomes granular

  7. Predentin
• Contour lines of owen

  1. Accentuated incremental lines due to disturbance in dentin matrix formation

  2. Hypocalcified bands
• Tomes granular

  1. Granular zone in dentin located adjacent to cementum

  2. Caused by coalescing and looping of terminal portions of dentinal tubules
• Interglobular dentin

  1. Hypomineralized areas in dentin that are due to failure of dentin to coalesce

  2. Defect in process of odontogenesis

  3. Found in crowns of teeth in the circumpulpal dentin below the mantle dentin
• Dentin

  • Color (light yellow – dark yellow)
  • Hardness greater than bone and cementum
  • Radiopaque
  • Highly permeable
  • Thickness (3-10 mm)
• Intertubular dentin

  1. Comprise the main body of the dentin

  2. Dentin located between peritubular dentin
• Incremental lines of von ebner

  Fine lines or striations in dentin that reflect the rhythmic deposition of dentin matrix
• Structures in dentin

  1. Dentinal tubules

  2. Peritubular dentin

  3. Intertubular dentin