15 - Dynamics and development of primary dentition. Development periods and stages. Fcators influencing tooth eruption. Mechanism, signs and sequence of eruption. Resorption organ. Pathology of tooth eruption

what does the primary dentition consist of and compare to permanent dentition?

• consist of 20 teeth, consisting of incisors, canines and molars.

• Unlike in permanent, there are no premolars present

• They are smaller overall and have whiter enamel than permanent teeth

Developemnt period and stages of primary dentition

1. Initiation (bud stage) - at leading edge of dental lamina 20 areas of enlargement appear, which form 20 buds for the primary teeth

2. Start of mineralisation - first the deposition and mineralisation of dentin matrix, then the first layer of enamel

3. Completion of crown - complete construction of enamel

4. Eruption - developing teeth emerge through soft tissue of jaws and overlying mucosa to enter the oral cavity

5. Development of tooth root proliferation of epithelial root sheath

factors influencing primary tooth eruption

• hereditary - maternal influence, gender, jaw

• Pathological - disease, endocrine issues, dental disease, trauma

• Environmental - race, geographic environment, social environment

Mechanism and signs of eruption of primary dentition

1. Pre eruptive phase

2. Prefunctional eruptive phase: 1. root development, 2. movement, 3. penetration, 4. intraoral occlusal or incisive movement

3. Functional eruptive phase

Sequence of eruption of primary dentition

1. mandibular incisors

2. maxillar incisors

3. maxillary 1st molar

4. mandibular 1st molar

5. mandibular canine

6. maxillary canine

7. mandibular second molar

8. maxillary second molar

Resorption organ

1. inner layer - osteoclasts and fibroblasts

2. Intermediate layer - layer of small cell infiltration

3. Outer layer - contains numerous capillaries among fibrous structure

Pathology of tooth eruption

• Dentitio praecox - premature eruption

• Dentino tarda - delayed eruption

• Eruption haematoma - bluish fluid filled swelling in gingiva overlying and erupted tooth caused by trauma to the soft tissues

• Dentitio difficilis - painful or difficult tooth eruption

• Dentitio praecox

• premature eruption

• Dentino tarda

• delayed eruption

• Eruption haematoma

• bluish fluid filled swelling in gingiva overlying and erupted tooth caused by trauma to the soft tissues

• Dentitio difficilis

• painful or difficult tooth eruption