What are the classes of teeth?
- Incisors: chisel shaped for cutting
- Cuspids (canines): fanglike teeth that tear or pierce
- Bicuspids (premolars)
- Tricuspids (molars)
Both bicuspids and tricuspids have broad crowns with rounded cusps for grinding or crushing.
At what age are permanent dentitions typically formed?
By age 21
This marks the completion of the transition from primary to permanent teeth.
How many primary or deciduous teeth erupt, and at what age?
20 primary teeth erupt (6-24 months of age)
These are also known as milk teeth.
What happens to primary teeth as permanent teeth develop?
- Roots are resorbed
- Teeth fall out (6-12 years of age)
This process allows for the emergence of permanent teeth.
How many permanent teeth do adults typically have?
32 permanent teeth
All except third molars erupt by the end of adolescence.
What are the three main regions of a typical tooth?
- Crown
- Neck
- Root
The crown is the exposed part above the gums, the neck joins the crown to the root, and the root is embedded in the alveolar process.
What is the crown of a tooth covered by?
Enamel
Enamel is the hardest tissue in the body, comprised of hydroxyapatite or calcium phosphate crystals.
What connects the crown to the root of a tooth?
Neck
The neck is the region that joins the crown to the root.
What is the root of a tooth embedded in?
Alveolar process
The root is the portion of the tooth that is embedded in the alveolar process.
What is the function of the alveolar process?
Surrounds and supports roots of teeth
The alveolar process is the bone that provides support for the roots of the teeth.
What is the apex of a tooth?
The tip of the root
The apex is the pointed end of the root of the tooth.
What type of bone is the cortical bone?
Compact bone
Cortical bone is dense and forms the outer layer of the bone structure.
What type of bone is cancellous bone?
Spongy bone
Cancellous bone is lighter and less dense than cortical bone, found inside the bone structure.
What are the main components of a tooth structure?
- Enamel
- Dentin
- Dentinal tubules
- Pulp cavity
- Neck
- Root
- Gingiva (gum)
- Cementum
Each component plays a crucial role in the overall health and function of the tooth.
What is the function of dentin in tooth structure?
Bone-like material under enamel
Dentin is maintained by odontoblasts of the pulp cavity.
What does the pulp cavity contain?
- Connective tissue
- Blood vessels
- Nerves
The pulp cavity is surrounded by dentin.
What is the root canal?
Extends from pulp cavity to apical foramen of root
The root canal is essential for the passage of nerves and blood vessels.
What is the role of the periodontal ligament?
Connects tooth to surrounding bone
It plays a vital role in tooth stability.
What is the apical foramen?
Opening at the tip of the root
It allows blood vessels and nerves to enter the tooth.
What is the composition percentage of hydroxyapatite in cementum?
~ 50%
Hydroxyapatite is a mineral form of calcium apatite, which is a major component of bone and teeth.
What type of tissue is cementum?
Calcified connective tissue
Cementum covers the root of the tooth and attaches it to the periodontal ligament.
What is the role of the periodontal ligament?
Attaches tooth to alveolar process
The periodontal ligament surrounds the tooth root and forms a fibrous, immovable joint called a gomphosis.
What is a gomphosis?
Fibrous, immovable joint
It anchors a tooth to its bony socket.
What is the gingival sulcus?
Groove where gingiva borders tooth
This is the space between the gum and the tooth.
