Development of Tooth - Part 1: Initiation, Bud and Cap stage of Tooth development

Summary

This video explores the early stages of tooth development during embryonic life, focusing on the bud and cap stages. Starting with the formation of maxilla and mandible in the sixth week, it details the transformation of the oral epithelium into structures like the dental lamina and dental placodes. The script explains how the tooth bud becomes the enamel organ and how the dental papilla forms the tooth’s dentin and pulp. As the process progresses into the cap stage, key cellular changes lead to the formation of the tooth germ, setting the stage for future tooth growth and development.

Takeaways

• 😀 The development of the maxilla and mandible begins in the sixth week of embryonic life.
• 😀 A thick band of epithelium forms around the upper and lower jaws during this period, resembling a horseshoe shape.
• 😀 The superficial layer of primary oral epithelium rests on the underlying ectomesenchyme and is separated by the basement membrane.
• 😀 In the seventh week, the primary oral epithelium subdivides into the vestibular lamina and the dental lamina.
• 😀 The vestibular lamina will give rise to the oral vestibule, while the dental lamina will give rise to the future teeth.
• 😀 Localized epithelial thickenings called dental placodes form on the dental lamina, playing a crucial role in initiating tooth formation.
• 😀 The tooth development process from dental placodes is continuous, with no clear-cut boundaries, but can be divided into three main stages: bud, cap, and bell stages.
• 😀 The bud stage begins in the eighth week, where epithelial swellings or dental placodes proliferate and invaginate into the ectomesenchyme.
• 😀 In the bud stage, the epithelial structure becomes the enamel organ, and the surrounding ectomesenchyme becomes the dental papilla.
• 😀 The cap stage begins in the ninth week, with the enamel organ taking a cap-like shape, and the dental lamina being pulled along with it.
• 😀 During the cap stage, the inner enamel epithelium becomes short columnar, the outer enamel epithelium becomes cuboidal, and the stellate reticulum forms between them.
• 😀 The successional dental lamina arises during the cap stage and will give rise to the permanent tooth successors.
• 😀 The dental follicle, surrounding the enamel organ and dental papilla, will eventually form the periodontal tissues of the tooth.
• 😀 Together, the enamel organ, dental papilla, and dental follicle make up the tooth germ, which forms the precursor to a tooth.

Q & A

What forms around the upper and lower jaws during the sixth week of embryonic life?

A thick band of epithelium forms around the upper and lower jaws during the sixth week of embryonic life, which roughly resembles a horseshoe in shape.

What separates the primary oral epithelium from the underlying ectomesenchyme?

The primary oral epithelium is separated from the underlying ectomesenchyme by a layer of the basement membrane.

What are the two subdivisions of the primary oral epithelium during the seventh week?

The primary oral epithelium subdivides into the vestibular lamina and the dental lamina during the seventh week.

What do the vestibular lamina and dental lamina give rise to?

The vestibular lamina gives rise to the oral vestibule, while the dental lamina gives rise to the future dentition.

What are the localized epithelial thickenings on the dental lamina called?

The localized epithelial thickenings on the dental lamina are called dental placodes.

What is the role of dental placodes in tooth development?

Dental placodes play a main role in the initiation of tooth formation.

How is the process of tooth development described in terms of stages?

The development of teeth from dental placodes is described as a continuous process, divided into three main stages: the bud stage, the cap stage, and the bell stage.

What happens during the bud stage of tooth development?

During the bud stage, localized epithelial swellings, known as dental placodes, proliferate and invaginate into the ectomesenchyme, forming the shape of a bud.

What structures are formed from the enamel organ and the dental papilla during the bud stage?

The enamel organ, which will give rise to the enamel, is formed from the epithelial bud, and the dental papilla, which will give rise to the dentin and pulp, forms from the condensed ectomesenchyme.

What changes occur in the enamel organ during the cap stage?

During the cap stage, the enamel organ takes on a cap shape, with the cells at the concave region becoming short columnar (inner enamel epithelium) and the cells at the convex region becoming short cuboidal (outer enamel epithelium).

What is the dental follicle and what does it give rise to?

The dental follicle, formed from the ectomesenchyme surrounding the enamel organ and dental papilla, will give rise to the periodontal tissues of the tooth.

What structures make up the tooth germ during tooth development?

The tooth germ is made up of the enamel organ, the dental papilla, and the dental follicle.