Sorry for the late submission, yall. Here it is:
26. Describe the developmental disturbances that can occur during the apposition and maturation stages of tooth development.
Enamel Pearl
Description: Sphere of enamel on root.
Etiological Factors: Displacement of ameloblasts to root surface.
Clinical Ramifications: May be confused as calculus deposit on root.
Enamel Dysplasia
Description: Faulty development of enamel from interference involving ameloblasts.
Etiological Factors: Local or systemic or hereditary.
Clinical Ramifications: Pitting and intrinsic color changes in enamel. Changes in thickness of enamel possible. Problems in function and aesthetics.
Concrescence
Description: Union of root structure of two or more teeth by cementum.
Etiological Factors: Traumatic injury or crowding of teeth.
Clinical Ramifications: Pitting and intrinsic color changes in enamel. Changes in thickness of enamel possible. Problems in function and aesthetics.
27. Describe the process of root development.
Root development occurs after the crown is completely shaped and the tooth has started to erupt into the cavity. The cervical loop, which is the most cervical portion of the enamel organ, grows deeper into the surrounding ectomesenchyme of the dental sac and creating Hertwig's epithelial root sheath (HERS). HERS shapes the root(s) and induces dentin formation in the root area. Root dentin is formed, followed closely by cementum and pulp formation. The process is similar to multi-rooted teeth with the multiple roots dividing from the root trunk.
28. What is Hertwig's epithelial root sheath?
An extension of the cervical loop that functions to shape the developing root and induce dentin formation in the root area.
29. How does root dentin form?
Outer cells of the dental papilla around the root area are induced to undergo differentiation and become odontoblasts which then begin to secrete predentin. Predentin later matures into dentin.
30. What are the epithelial rests of Malessez, and what complication is associated with them?
Epithelial cells derived from disintegrated HERS that are located in the mature PDL and can eventually become cystic.