Odontoclastic Resorption at the Pulpal Surface of Coronal Dentin Prior to the Shedding of Human Deciduous Teeth

Histological and histochemical observations of more than 150 extracted human deciduous teeth revealed that, prior to shedding, odontoclastic resorption as a rule takes place at the pulpal surface of coronal dentin. We also found that this phenomenon occurs in all kinds of deciduous teeth. The process of this internal resorption of coronal dentin of deciduous teeth clearly showed time-related histological changes. During the time the roots were actively being resorbed, the pulpal tissue retained its normal structure. However, when root resorption neared completion, inflammatory cells started to gradually infiltrate into the pulp, and odontoblasts began to degenerate. After that, multinucleate odontoclasts appeared, and resorption proceeded from the predentin to the dentin. The odontoclastic activity was initially detected only on the pulpal surface at the bottom areas of the crown. It gradually spread towards the pulpal horn regions along the wall of the pulp chamber. However, this internal resorption of coronal dentin did not continue until the teeth were finally shed. After the elimination of resorption, the resorbed dentin surface was repaired by a cementumlike deposition or covered with fibrous connective tissue.