Shedding Of Teeth PDF

Shedding of Teeth Dr. Sandeep Gupta Assistant Professor  Shedding The normal physiological process resulting in elimination of deciduous teeth is called shedding or exfoliation. The loss of deciduous teeth is mainly due to the resorption of their roots. Commenc...

Shedding of Teeth Dr. Sandeep Gupta Assistant Professor  Shedding The normal physiological process resulting in elimination of deciduous teeth is called shedding or exfoliation. The loss of deciduous teeth is mainly due to the resorption of their roots. Commences earlier in girls than in boys.  Need of Shedding With the growth of child the jaw grows but the deciduous cannot. Muscle of mastication increases in size and power of contraction. PDL of deciduous teeth cannot withstand the masticatory forces. Thus the shedding of deciduous teeth and replacement by larger permanent teeth is needed.  Shedding of primary teeth A six year old girl's deciduous teeth, which are beginning to fall out.  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 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 resorb bone PDL is resorbed by fibroclast  Pattern of shedding Anterior teeth: Resorption of deciduous teeth starts from lingual side. Later developing tooth occupy position directly apical to deciduous teeth. Shedding of anterior teeth Shedded crown Shed element following “shedding of primary incisor Complete resorption of roots Resorption lacunae seen (arrow) Most of coronal pulp is intact  Pattern of shedding Posterior Teeth: The resorption of deciduous teeth begins on the inner surface of the roots of molar The resorption occurs long before the deciduous molars are shed. Eruption for secondary tooth and shedding for posterior deciduous Shedding of posterior teeth  Shedding of Teeth First step: Pressure from successional teeth Leads to activation of---- 1. Osteoclast 2. Odontoclast (cementoclast; dentinoclast) 3. Fibroclast 1.Osteoclasts are bone resorbing cells derived form monocyte- macrophage lineage Giant multinuclear cells with 4-20 nuclei Osteoclasts resorb hard tissue by separating mineral from the collagen matrix through the action of hydrolytic enzymes Resorption occurs at the ruffled border which greatly increases the surface area of the osteoclast in contact with bone Hard Tissue resorption: 1. Extracellular phase 2. Intracellular phase Osteoclast resorbing the bone  2. Odontoclast Resorption in dentin Odontoclast in a process of resorption of dentin Cells responsible for shedding  Odontoclast: Origin and function Origin: Circulating Monocytes Function: Resorption of all dental hard tissue including Enamel 3. Fibroclast/Fibroblast PDL resorbed by fibroclast  3. Fibroclast/Fibroblast Note the collagen fiber fragments inside the fibroclast (Head arrows)  Clinical consideration Remnants of the root of deciduous teeth Retained /Submerged deciduous teeth Pathological resorption Retained Primary teeth Submerged primary teeth Pathological Resorption : Impacted maxillary canine Pathological Resorption : Impacted mandibular third molar Thank You