Oral Histology & Development

Dentin Characteristics

Incremental lines

Von Ebner lines

  • Banding along the dentinal tubules 
  • Perpendicular to dentinal tubules

  • The dentine formation occurs incrementally ~ 4mm / day.
  • A change of collagen fiber orientation was seen more clearly after 5-day cycle of this daily deposition  
Contour lines of Owen
In longitudinal ground sections, they appeared as dark bands. 

  • Changes in the coloration of the dentin
  • Periods of illness
  • Changes of body metabolism or inadequate nutrition

Tom's granular layer:

  • Black granules.
  • Only clear in ground section. 
  • Increasing in the granules occurs from the CEJ to the apex of the tooth
  • Visible in radicular (root) dentin near DCJ

  • Looping back of dentinal tubules
  • Special arrangement of collagen & non- collagenous proteins between dentin and cementum

Interglobular dentine:

  • This pattern of mineralization is best seen in circumpulpal dentin just below mantel dentin, because of the globular pattern of mineralization in this region
  • In a ground section of dentin, the less-calcified areas of dentin appear as irregularly shaped crescents


  • Areas of unmineralised or hypomineralised dentin, where globular zones of mineralization defect to fuse into a homogenous mass within mature dentin
  • Common in persons with Vitamin D deficiency or high levels of Fl- at the time of dentinogenesis

Changes in dentinal tubules:

Dead tracts

  • Appears dark in ground sections
  • Mostly in the coronal Dentine


  • They occur as age change
  • A severe injury or stimulus causes the odontoblasts to be destroyed in the region
  • When dentin is damaged, odontoblastic processes die or retract leaving empty dentinal tubules

Sclerotic dentine
  • Dentin appeared glassy and becomes translucent
  • Is most common in the apical third of the root


  • Increase with age
  • Due to noxious stimuli as in chronic caries
  • Irritated odontoblasts forms sclerotic dentin as a protective wall