in the process of eruptn,prefunctional eruptive stage of tooth begins when the
1 bud stage begins
2 cap stage begins
3 bell stage begns
4dental lamina begins forming
5 none of above
Ans:5.
Life cycle of tooth begins with formation of dental lamina and then
1.Initiation(Bud stage).
2.Proliferation(Cap stage).
3.Histomorphodifferentiation(Bell stage).
4.Apposition(formation of enamel and dentin matrix).
5.Eruption.
Histological phases of eruption:
1) Pre-eruptive phase:
It starts at the beginning of tooth development and ends when the crown formation is completed.
It is characterized by:
a) Growth of tooth germ i.e. dental (enamel) organ, dental papilla and dental sac.
b) Formation of bony crypt.
c) Movement of developing tooth within the growing jaw. Different types of movement occurs: bodily, axial, rotational and eccentric( i.e. shifting the long axis of the developing tooth). This eccentric movement is associated with differential growth.
2) Prefunctional ( Eruptive) phase:
It starts at the beginning of root formation and ends when the tooth reaches occlusion. It is characterized by:
a) Formation of the root.
b) Bone apposition especially at the fundus of the crypt.
c) Initial organization of periodontal ligament.
d) Rapid active eruption
3) Functional ( Posteruptive ) phase:
It starts when the erupting tooth reaches occlusion with its antagonists and lasts throughout the life of the tooth.
It is characterized by:
a) Occlusal active eruption (more cementum and alveolar bone apposition).
b) Occlusomesial physiological drift ( alveolar bone remodeling ).
c) Organization of periodontal ligament principal fibers.
