1. Digestive System:
Outcome: I can describe the structure of a tooth and accurately label the teeth anatomically.
Drill:
What is the function of the uvula?

2. Components of a Tooth Crown Dentin Occlusal surface Pulp cavity Enamel
Neck
Gingival sulcus
Cementum
Periodontal ligament
Root
Root canal
Apical foramen
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Figure 22.7 1

3. Teeth Regions of a tooth Crown Neck Root
Portion projecting into the oral cavity from the surface of the gums
Neck
The boundary between the crown and root
Root
Portion below the gum line
Sits in a bony tooth socket called an alveolus
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4. Teeth Components of a tooth
The bulk of each tooth is composed of dentin
Mineralized matrix similar to bone but contains no cells
Pulp cavity
The interior chamber of the tooth
Occlusal surface
Portion of the crown used for crushing, slicing, or chewing
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5. Teeth Components of a tooth (continued) Enamel Gingival sulcus
Covers the dentin of the crown
Hardest biologically manufactured substance
Composed of calcium phosphate
Requires calcium, phosphate, and vitamin D for formation and resistance to decay
Gingival sulcus
Shallow groove surrounding the base of the neck
Epithelial attachment blocks bacteria from accessing deeper tissues around the root
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6. Teeth Components of a tooth (continued) Cementum Periodontal ligament
Covers the dentin in the root
Less resistant to erosion than dentin
Periodontal ligament
Creates gomphosis articulation between root dentin and alveolar bone
Root canal
Narrow tunnel within the root of the tooth
Passageway for blood vessels and nerves to the pulp cavity
Opening into the root canal is the apical foramen
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7. Types of Teeth Incisors Cuspids Bicuspids Molars Upper jaw Lower jaw
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Figure 22.7 2

8. Teeth Four types of teeth
Each with a distinctive shape and root pattern
Incisors
Blade-shaped teeth with a single root
Located at the front of the mouth
Useful for clipping or cutting
Cuspids (or canines)
Conical with a sharp ridgeline and pointed tip
Used for tearing or slashing
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9. Teeth Four types of teeth (continued) Bicuspids (or premolars)
Have flattened crowns with prominent ridges
Used for crushing, mashing, or grinding
Molars
Very large flattened crowns with prominent ridges
Adapted for crushing and grinding
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10. Teeth Two sets of teeth Formed during embryonic development
Primary dentition (deciduous teeth)
Also called primary teeth, milk teeth, or baby teeth
At 2 years of age
20 deciduous teeth
5 on each side of upper and lower jaws
2 incisors, 1 cuspid, 2 deciduous molars
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11. Central incisors (7.5 mo)*
Primary dentition
Central incisors (7.5 mo)*
Lateral incisor (9 mo)
Cuspid (18 mo)
Deciduous 1st
molar (14 mo)
Deciduous 2nd
molar (24 mo)
Deciduous 2nd
molar (20 mo)
Deciduous 1st
molar (12 mo)
Cuspid (16 mo)
Lateral incisor (7 mo)
Central incisors (6 mo)
Deciduous teeth
*Indicates month of eruption
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Figure 22.7 3

12. Teeth Two sets of teeth (continued) Secondary dentition
Gradually replace primary dentition
Primary teeth fall out or are pushed aside by secondary teeth
Three additional molars appear on each side of the upper and lower jaws
Third molars are called wisdom teeth
32 total permanent teeth
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13. Figure 22.7 4 Central incisors (7–8 yr)* Lateral incisor (8–9 yr)
Secondary dentition
Central incisors (7–8 yr)*
Lateral incisor (8–9 yr)
Cuspid
(11–12 yr)
1st Premolar
(10–11 yr)
Maxillary
dental
arcade
2nd Premolar
(10–12 yr)
1st Molar
(6–7 yr)
2nd Molar
(12–13 yr)
3rd Molars
or wisdom
teeth
(17–21 yr)
2nd Molar
(11–13 yr)
1st Molar
(6–7 yr)
2nd Premolar
(11–12 yr)
Mandibular
dental
arcade
1st Premolar
(10–12 yr)
Cuspid (9–10 yr)
Lateral incisor (7–8 yr)
Central incisors (6–7 yr)
Adult teeth, upper and lower jaws
*Indicates year of eruption
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Figure 22.7 4

14. Teeth Dental diseases Gingivitis Inflammation of the gingivae
Stimulation from brushing and massaging gums can strengthen those epithelial attachments
Severe cases usually caused by bacterial infection
Can progress to erosion of gums, root damage, and tooth loss
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15. Teeth Dental diseases (continued) Tooth decay
Generally results from action of bacteria (normally found in the mouth)
Bacteria adhere to tooth surfaces and trap food particles
Produce deposits called dental plaque
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16. How many primary and secondary teeth are there in humans?
Digestive System:
Exit Ticket:
How many primary and secondary teeth are there in humans?