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FORMATION OF PERMANENT TOOTH ,ROOT AND

SUPPORTING TISSUES

PERMANENT TOOTH FORMATION

• Between 20th utero week anf 10 months after birth

• Arises from dental lamina• Bud on the lingual aspect of deciduous tooth

FORMATION OF PERMANENT MOLARS

• Between 20th week of utero(first molar) and after 5 years of age (third moalr).

ROOT FORAMTION

• Two types of roots are formed:1. Single root formatiuon2. Multiple root formation

SINGLE ROOT FORMATION

• Initiation from cervical loop

• Hertwig’s epithelial root sheath

Single Root Formation

• Formation of Apical foramen•

ROOT DENTIN

• HERS sends inductive signal to ectomesenchymal pulp cells to secrete predentin by differentiating into odontoblasts

Multiple Root Formation

• Epithelial diaphragm of root sheath develops tongue type extensions

Multiple Root Formation

Formation of Supporting Tissues

1.Bone 2.Gingiva3.Cementum4.Periodontal ligaments

Developing of Alveolar bone

• Develop by the differentiation of dental follicle cells!

Development Of Gingiva• The fusion of reduced enamel epithelium and oral epithelium at the tooth

eruption stage• The resulting cuff and epithelium surrounds the neck of the tooth

developing the gingiva

Formation Of Cementoblast

Periodontal Ligaments

Formation Of PDLStep 1.Organic matrix from rests of malassezStep 2.Mineralization of the matrixStep 3.Anchoring of periodontal ligament(bundle of fibres)