SHEDDING OF DECIDUOUS TEETH

• Diphyodont


  Having two generations of dentition
• Generations of human dentition

  • Primary dentition/Temporary dentition
  • Secondary dentition/Permanent dentition
• Shedding/Exfoliation


  Physiologic process resulting in elimination of deciduous dentition
• Shedding of deciduous teeth

  1. Progressive resorption of the roots of teeth and supporting tissues – the periodontal ligament

  2. Pressure generated by the growing and erupting permanent tooth dictates the pattern of shedding
• Shedding of anterior teeth

  • Pressure directed against the root surface of the deciduous tooth
  • Physiologic movement is in occlusal and vestibular direction
  • Resorption begins on the lingual surface
  • Permanent tooth occupies position directly apical to deciduous tooth (except mandibular incisors)
  • Temporary tooth shed before root resorption is complete
• Shedding of posterior teeth

  • Resorption begins at the inner surfaces
  • Developing bicuspids are between roots of deciduous molars
  • Apical positioning or the permanent bicuspids a result of a continuous growth of jaws and occlusal movement of temporary molars
  • Temporary molars' root are completely resorbed and crown is partially resorbed before exfoliation
• Odontoclasts


  • Cells responsible for removal of dental hard tissue
  • Has ability to resorb all dental hard tissue including enamel
  • Similar in structure to osteoclast (multinucleated cells, occupy resorption bays on the surface of hard tissue, cytoplasmic vacuoles)
  • Appear on surfaces of roots of primary tooth with advancing permanent tooth
• Periodontal ligament


  Undergoes apoptotic cell death (shrinkage and death of cells so that they can be phagocytosed by neighboring cells)
• Mechanism of resorption and shedding

  1. Pressure from erupting permanent tooth

  2. Odontoclasts adhere to hard tissue surface and acidify it so that demineralization occurs

  3. Forces of mastication initiate resorption

  4. Increase in size and forces exerted by muscles of mastication
• Remnants of deciduous teeth

  • Consist of dentin and cementum
  • May remain embedded in jaw (dec. mand. 2nd molar)
  • Ankylosed to the bone
  • May be ultimately exfoliated
  • Progressively resorbed
• Retained deciduous teeth


  • Teeth without permanent successors - Impacted successors
  • Impacted temporary predecessor
  • Odontogenic tumor
• Submerged deciduous teeth


  • Result of trauma to the dental follicle or developing periodontal ligament
  • May result to ankylosis of temporary tooth
  • May prevent eruption of permanent successors