16 - Dynamics and development of permanent dentition. Development periods and stages. Deevelopment and formation of the roots. Factors influencning tooth eruption. Mechanism and sequence of eruption. Pathology of tooth eruption

how many teeth in permanent dentition and what are they?

• 32 teeth

• Consists of incisors, canines, premolars and molars

development periods and stages of permanent dentition

1. process of laying down tooth germ - from 4th embryonic month to 9th month after birth

2. Start of mineralisation - 9th month of embryonic life

3. Crown formation - 3-8 years

4. Eruption - Pre-eruptive phase, prefunctional eruptive phase, functional eruptive phase

5. Development of root

Development and formation of roots in permanent dentition

1. start of root development

2. Short root walls

3. Root walls are close to final length

4. Constructed root walls - apex is open

5. Constructed root walls - apex is closed

Factors influencing tooth eruption

• Hereditary - maternal influence, gender, jaw

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

• Environmental - race, geographic environment, social environment

Mechanism and sequence of eruption

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 permanent dentition

1. mandibular and maxillary 1st molars

2. mandibular incisors

3. maxillary incisors

4. mandibular and maxillary 1st premolars

5. mandibular and maxillary canines

6. mandibular and maxillary 2nd premolars

7. mandibular and maxillary 2nd molars

types of tooth eruptions/ pathology of tooth eruption

• Dentitio pracox - premature eruption

• Dentitio tarda - delayed eruption

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

• Dentitio difficilis - painful or difficult tooth eruption