Tooth Eruption Question And Answers

Tooth Eruption

Describe tooth eruption. (or) Describe in detail pre-eruptive, eruptive, and post-eruptive tooth movements.
Answer:

Tooth eruption:

It means the axial or occlusal movement of the tooth from its developmental position within the jaw to its functional position in the occlusal plane.
It consists of the following tooth movements.

1. Pre-eruptive tooth movement:

When the deciduous tooth germs first differentiate they are extremely small and there is a good amount of space available for eruption.
But as they grow rapidly, they become crowded.
It is compensated by the growth of the jaws in length which permits the drifting of tooth germs The deciduous second molar tooth germs move backward and the anterior germs move forward.
At the same time, the tooth germs are moving bodily outward and upward.
The re-eruptive tooth movement is made by the deciduous and permanent tooth germs within the tissues of the jaw before they begin to erupt.
The permanent tooth buds which arise lingual to the deciduous predecessors migrate in a buccal direction.
The pre-eruptive movements occur in an intraosseous location and are reflected in the patterns of bony remodeling within the crypt wall.

2. Eruptive tooth movement:

It is made by a tooth to move from its position within the bone of the jaw to its functional position in occlusion.
It includes the formation of the roots, the periodontal ligament, and the dentogingival junction.
Root formation is initiated by the growth of Hertwig’s epithelial root sheath.
It overall increases the length of the tooth.
Depending on the rate at which the root elongates the basal bone will resorb or form to maintain a proper relationship between the root and bone.
Shortly after the onset of root formation, the cementum, periodontal ligament, and the bone lining the crypt wall are formed.
A number of structural changes occur in the periodontal ligament that is responsible for tooth movement.

3. Post-eruptive tooth movement:

Maintaining the position of the erupted tooth in occlusion while the jaws continue to grow and compensate for occlusal and proximal tooth wear.
It is made by the tooth after it has reached its functional position in the occlusal plane.
They are divided into three categories.
The movement to accommodate the growing jaws.
They are completed towards the end of the second decade.
The tooth is readjusted to the growing jaws by the formation of new bone at the alveolar crest and on the socket floor.
Readjustment occurs between the ages of 14 – 18 years.
During this active movement of the tooth takes place.
Movements to compensate for occlusal wear.
Compensation for occlusal wear is achieved by continued deposition of cementum around the apex of the tooth.
Movements to accommodate interproximal wear.
The interproximal wear is compensated by a process mesial drift.
The forces causing mesial drift may include occlusal force, contraction of the transseptal ligament between teeth, and soft tissue pressure.

Tooth Eruption