Anatomy of Teeth Lecture Notes

Introduction

• Presenter: Ben from registerednessrn.com
• Topic: Anatomy of Teeth
• Question: Are teeth considered bones?
  • Answer: False
  • Reason: Teeth and bones have different properties, and anatomists do not classify teeth as bones.

Major Parts of a Tooth

1. Crown
   • Visible portion above the neck, extends out of gums.
   • Covered by enamel (protective layer).
   • Enamel covers dentin and underlying pulp chamber/pulp.
2. Neck (Cemento Enamel Junction or Cervical Line)
   • Attachment point for gingiva (gums).
   • Area where enamel meets cementum layer.
   • Visible line on an extracted tooth.
3. Root
   • Extends from neck to root's apex.
   • Secured to alveolar bone in mandible or maxilla.
   • Incisors have 1 root, molars can have 2 or 3 roots.
   • Covered by cementum (protective layer).
   • Contains dentin, underlying root canal, and pulp.

Major Tissue Types in Teeth

1. Enamel
   • Hardened outer layer of the crown.
   • No living tissues (vessels, nerves, or cells).
   • Composed of minerals (mostly hydroxyapatite).
   • Hardest substance in the human body.
   • Vulnerable to acid from dental plaque and acidic foods.
2. Cementum
   • Covers the tooth's root.
   • Formed by cementoblasts.
   • Light yellow, softer than enamel and dentin.
   • Attached to periodontal ligament, securing the tooth to its socket.
   • Part of the periodontium (includes gums, periodontal ligament, alveolar bone proper).
3. Dentin (Dentine)
   • Located beneath enamel (crown) and cementum (root).
   • Formed/maintained by odontoblasts.
   • Makes up most of the tooth's mass.
   • Contains 70% mineral content, harder than cementum and bone, but softer than enamel.
   • Contains dental tubules that transfer nutrients from pulp to dentin.
   • Dentino Enamel Junction (DEJ) and Dentino Cemental Junction (DCJ) are critical borders.
4. Pulp
   • Soft tissue within the pulp cavity.
   • Pulp cavity has a narrow root canal and a larger pulp chamber.
   • Contains odontoblasts, vessels, and nerves for nutrition, sensation, immune defense, and dentin maintenance.
   • Root canal originates at apical foramen and extends to the pulp chamber in the crown.

Types of Teeth

1. Incisors
2. Canines (Cuspids)
3. Premolars (Bicuspids)
4. Molars

Conclusion

• Next Topic: More details on the four types of teeth.
• Additional Resources: Free quiz and playlist of anatomy videos available on the website.
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