Shedding of Deciduous Teeth

Shedding of Teeth

• Shedding, or exfoliation, is the normal physiological process resulting in the elimination of deciduous teeth.
• The loss of deciduous teeth is mainly due to the resorption of their roots.

Need of Shedding

• The jaw grows as the child grows, but the deciduous teeth cannot.
• The muscle of mastication increases in size and power of contraction, which the PDL of deciduous teeth cannot withstand.
• Shedding of deciduous teeth and replacement by larger permanent teeth is necessary.

Rules of "Sixes" in Dental Development

• 6 weeks old in utero: beginning of dental development
• 6 months old: emergence of the first primary tooth
• 6 years old: emergence of the first permanent tooth

Mechanism of Shedding

• Pressure of the succeeding permanent teeth
• Increase in force of mastication
• Action of odontoclast (cementoclast for the cementum and dentinoclast for the dentin)
• Action of osteoclast, which resorbs bone
• PDL is resorbed by fibroclast

Pattern of Shedding

• Anterior teeth: Resorption of deciduous teeth starts from the lingual side.
• Later developing teeth occupy a position directly apical to deciduous teeth.
• Posterior teeth: The resorption of deciduous teeth begins on the inner surface of the roots of molars.

Cells Responsible for Shedding

• Osteoclast: bone-resorbing cells derived from the monocyte-macrophage lineage, responsible for hard tissue resorption.
• Odontoclast: responsible for resorption of all dental hard tissue, including enamel, derived from circulating monocytes.
• Fibroclast/Fibroblast: responsible for PDL resorption.