Dental Anatomy

1. Dental Trauma:
-Anatomy of Dentition
- Primary & Permanent
tooth development
Peter Andre Soltau
DM Emergency Medicine UWI
Year 2 Resident

2. Traumatic Dental Injuries
(TDIs)
 Most common age is 1.5 to 2.5
years
 Commonest causes:
◦ Falls / Collisions
◦ Child Abuse (Non-accidental)
◦ Sports or play related injuries
◦ MVA / Bicycle accidents

3. Epidemiology
 Boys/girls - 2/1
 Maxillary incisors most frequently
injured
 Primary dentition - luxations
 Permanent dentition-
uncomplicated crown fractures

4. Traumatic Dental Injuries
(TDIs)

5.  The primary goal is to delineate an
approach for the immediate or urgent
care of TDI

6. Embryology of Teeth

7. Upper Teeth:
55/A, 65/J Second molar
25-33±month eruption
10-12±year exfoliation
54/B, 64/I First molar
13-19±month eruption
9-11±year exfoliation
53/C, 63/H Cuspid (Canine)
16-22±month eruption
10-12±year exfoliation
52/D, 62/G Lateral incisor
8-13±month eruption
7-8±year exfoliation
51/E, 61/F Central incisor
8-12±month eruption
6-7±year exfoliation

8. Lower Teeth:
75/K, 85/T Second molar
23-31±month eruption
10-12±year exfoliation
74/L, 84/S First molar
14-18±month eruption
9-11±year exfoliation
73/M, 83/R Cuspid (Canine)
17-23±month eruption
19-12±year exfoliation
72/N, 82/Q Lateral incisor
10-16±month eruption
7-8±year exfoliation
71/O, 81/P Central incisor
6-10±month eruption
6-7±year exfoliation

9. Embryology of Teeth

10. Upper Teeth:
18/1, 28/16 Third molar
17-21±year eruption
17/2, 27/15 Second molar
12-13±year eruption
16/3, 26/14 First molar
6-7±year eruption
15/4, 25/13 Second bicuspid (premolar)
10-122±year eruption
14/5, 24/12 First bicuspid (premolar)
10-11±year eruption
13/6, 23/11 Cuspid (Canine)
11-12±year eruption
12/7, 22/10 Lateral incisor
8-9±year eruption
11/8, 21/9 Central incisor
7-9± eruption

11. Lower Teeth:
38/17, 48/32 Third molar
17-21±year eruption
37/18, 47/31 Second molar
12-13±year eruption
36/19, 46/30 First molar
6-7±year eruption
35/20, 45/29 Second premolar
10-12±year eruption
34/21, 44/28 First premolar
10-11±year eruption
33/22, 34/27 Cuspid (Canine)
11-12±year eruption
32/23, 42/26 Lateral incisor
8-9±year eruption
31/24, 41/25 Central incisor
7-8±year eruption

12. Embryology of Teeth

13.  When a tooth is first formed, it is
nothing more than "germ cells," that
forms within the bone.
Embryology of Teeth

14. Embryology of Teeth
 The first part of the tooth that forms in
the bone is the outer shell of the
enamel

15. Embryology of Teeth
 While developing within the bone, before it
comes through the surface, it starts
growing the tooth root
 The blood flow that goes into the middle of
the tooth starts laying down calcium,
phosphorous, magnesium and other
minerals

16. Embryology of Teeth
 Finally, the developing tooth starts
erupting into the mouth.

17. Embryology of Teeth
 When the tooth first comes into the
mouth, it does not have a fully
developed root structure.
 It is not completely developed until
about the age of 15 to 20 years(fully
calcify)

21. Anatomy of Dentition
 The crown is the part of the tooth that is
visible above the gum (gingiva).
 The neck is the region of the tooth that
is at the gum line, between the root and
the crown.
 The root is the region of the tooth that
is below the gum. (Some teeth have
only one root, for example, incisors and
canine (‘eye’) teeth, whereas molars
and premolars have 4 roots per tooth).

23. Anatomy of Dentition
 The crown
 The crown of each tooth has a
coating of enamel, which protects
the underlying dentine. Enamel is
the hardest substance in the
human body, harder even than
bone. It gains its hardness from
tightly packed rows of calcium
and phosphorus crystals within a
protein matrix structure.

24. Anatomy of Dentition
 Dentine
 The major component of the inside of
the tooth
 a ‘live’ tissue.
 This substance is slightly softer than
enamel, with a structure more like bone.
 It is elastic and compressible in contrast
to the brittle nature of enamel.
 Dentine is sensitive. It contains tiny
tubules throughout its structure that
connect with the central nerve of the
tooth within the pulp.

25. Cementum and the
periodontal membrane
 Below the gum, the dentine of the
root is covered with a thin layer
of cementum, rather than enamel.
 Cementum is a hard bone-like
substance onto which the
periodontal membrane attaches.
 This membrane bonds the root of
the tooth to the bone of the jaw.
 Contains elastic fibres to allow
some movement of the tooth within
its bony socket.

26. Anatomy of Dentition
 The pulp
 Forms the central chamber of the tooth
 Made of soft tissue and contains blood
vessels to supply nutrients to the tooth,
and nerves to enable the tooth to sense heat and
cold.
 Also contains small lymph vessels which carry
white blood cells to the tooth to help fight bacteria.
 The root canal
 The extension of the pulp within the root of the
tooth
 Connects with the surrounding tissue via
the opening at the tip of the root.

33. The Innervation of Teeth
• Maxillary Teeth:
• Anterior superior alveolar nerve: upper incisors and
canines (CNV2)
• Middle superior alveolar nerve: upper premolars and
the mesio-buccal root of the maxillary first molar
(CNV2)
• Posterior superior alveolar nerve: upper molars
except the mesio-buccal root of the maxillary first
molar (CNV2)
• Mandibular Teeth:
• Inferior alveolar nerve: mandibular teeth, gingiva and
lower lip unilaterally (CNV3)

34. Blood Supply
• Maxillary teeth:
• Maxillary Artery - Superior alveolar
artery
: anterior, middle and posterior
• Mandibular teeth:
• Maxillary Artery - Inferior alveolar artery

37. Questions?

38. References
 1. Andreasen JO, Andreasen FM,
Andersson L. Textbook and Color Atlas of
Traumatic Injuries to the Teeth. 4th ed.
Oxford, England, Wiley-Blackwell: 2007.
 2. Petersson EE, Andersson L, Sorensen
S. Traumatic oral vs non-oral injuries.
Swed Dent J 1997; 211-2):55-68.
 3. Glendor U. Epidemiology of traumatic
dental injuries – a 12 year review of the
literature. Dent Traumatol 2008:24(6):603-
11.
 4. Flores MT. Traumatic injuries in the
primary dentition. Dent Traumatol 2002;
18(6):287-98