3. The Dentition
Teeth arranged to form two arches, named by the
bone which composes it
Maxilla forms the maxillary or upper arch
Mandible forms mandibular or lower arch
Two arches make up one dentition or set of teeth
Two dentitions over a lifespan
Primary (deciduous) and permanent
4. Primary or Deciduous Dentition
Begin to emerge into mouth about 6-8 months age
Teeth erupt following a developmental schedule
20 teeth
10 maxillary and 10 mandibular
Fully erupt by age 2½-3 years
Eventually replaced by permanent teeth
5. Permanent Dentition
32 permanent teeth
16 maxillary and 16 mandibular
Mandibular first molar is the first permanent
tooth
Between ages 5 & 6
Erupts next to last primary molar
7. Permanent Dentition
Between ages 5-12, mixed dentition is present
Both deciduous and permanent teeth in the mouth
together
Permanent teeth that replace the deciduous are
referred to as succedaneous
8. Permanent Teeth
Incisors are the four sharp-edged front teeth
Two central, two lateral
Incises/cuts food
Canines, aka cuspids, corner teeth with one pointed
cusp
Holds/tears food
9. Permanent Teeth
Premolars aka bicuspids, posterior teeth with two
cusps
Named by sequence from front to back in arch
Crushes/tears food
Molars are broad back teeth, several cusps
Named by sequence from front to back in arch
Chews/crushes/grinds food: mastication
10. The Arrangement of the Teeth
Anterior teeth
Front of the mouth, include incisors and canines
Posterior teeth
Back of the mouth, include premolars and molars
11. The Eruption Sequence
Teeth begin to form in utero, eruptions begin to
occur at approximately 6-8 months of age
Mandibular teeth generally precede maxillary teeth
Active eruption period continues until crown is almost
completely exposed and tooth is in proper alignment
In later life, the “gums” or gingival line, may recede,
exposing more of the tooth, this is called passive
eruption.
12.
13.
14. Eruption Sequence
Eruption dates vary from person to person by a few
months
By the age of 2.5-3 years old, all deciduous teeth have
erupted
At about 6, the permanent teeth start to erupt
Which tooth?
First molars are the first permanent tooth to erupt
Posterior to the deciduous second molar
Nonsuccedaneous
15. The Eruption Sequence
Tooth height can decrease throughout life due
to wearing away of biting and chewing surfaces
Wearing away is called attrition
Teeth grinding (bruxism) also causes attrition
Abrasion is caused by mechanical wear from
biting or vigorous brushing
16.
17. Line Angle
The area of the tooth
where two surfaces
meet, such as the line
that joins the buccal
and mesial surfaces
would be called the
mesio-buccal line
angle
18. Point Angle
The area of the tooth
where three surfaces
meet
The joining point of the
occlusal, lingual, and
mesial surfaces
20. Divisions of the tooth
The crown
Portion of the tooth normally visible in the mouth
Covered with enamel
Teeth have different shaped crowns, each adapted to perform a specific function in reducing
food for digestion
The cervix (neck)
The crown joins the root at the Cementoenamel junction (CEJ)
Junction between the anatomic crown and the anatomic root
The root
Located in the bone and not normally visible
Covered with cementum
Stabilize/support teeth when the pressure from mastication is exerted
21. Anatomic vs Clinical
The anatomic crown is covered with enamel
The anatomic root is covered with cementum
After eruption is complete, only the anatomic crown is seen in the
mouth
Later in life, as part of the aging process, the gingiva and bone may
recede, exposing a portion of the root.
All of the tooth that is visible in the mouth, the crown AND the
exposed root together are referred to as the clinical crown
The clinical crown extends from the biting surface of the tooth to the
gingival margin
22. Surfaces of the tooth
Mesial: surface closest to the midline
Distal: surface farthest, or most distant, from the midline
Facial: the surfaces closest to the face or outer sufaces of the teeth
Labial: facial surface of anterior teeth or surfaces closest to the lip
Buccal: facial surface of posterior teeth or surfaces closest to the cheek
Lingual: surfaces closest to the tongue or palate; all inner surfaces
Occlusal: chewing surfaces of posterior teeth
Incisal edge: biting surface of anterior teeth
23.
24. Terms relating to tooth surfaces
Proximal: the surface of the
tooth that is next to, or
beside, the adjacent tooth
Mesial and distal are both
proximal surfaces
