Dental Trauma:

-Anatomy of Dentition

- Primary & Permanent

tooth development

Peter Andre Soltau

DM Emergency Medicine UWI

Year 2 Resident

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

Epidemiology

Boys/girls - 2/1

Maxillary incisors most frequently

injured

Primary dentition - luxations

Permanent dentition-

uncomplicated crown fractures

Traumatic Dental Injuries

(TDIs)

The primary goal is to delineate an

approach for the immediate or urgent

care of TDI

Embryology of Teeth

Upper Teeth:

55/A, 65/J Second molar

25-33±month eruption10-12±year exfoliation

54/B, 64/I First molar

13-19±month eruption9-11±year exfoliation

53/C, 63/H Cuspid (Canine)

16-22±month eruption10-12±year exfoliation

52/D, 62/G Lateral incisor

8-13±month eruption7-8±year exfoliation

51/E, 61/F Central incisor

8-12±month eruption6-7±year exfoliation

Lower Teeth:

75/K, 85/T Second molar

23-31±month eruption10-12±year exfoliation

74/L, 84/S First molar

14-18±month eruption9-11±year exfoliation

73/M, 83/R Cuspid (Canine)

17-23±month eruption19-12±year exfoliation

72/N, 82/Q Lateral incisor

10-16±month eruption7-8±year exfoliation

71/O, 81/P Central incisor

6-10±month eruption6-7±year exfoliation

Embryology of Teeth

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

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 incisor8-9±year eruption

31/24, 41/25 Central incisor7-8±year eruption

Embryology of Teeth

When a tooth is first formed, it is

nothing more than "germ cells," that

forms within the bone.

Embryology of Teeth

Embryology of Teeth

The first part of the tooth that forms in

the bone is the outer shell of the

enamel

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

Embryology of Teeth

Finally, the developing tooth starts

erupting into the mouth.

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)

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).

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.

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.

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.

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.

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)

Blood Supply

• Maxillary teeth:

• Maxillary Artery - Superior alveolar

artery

: anterior, middle and posterior

• Mandibular teeth:

• Maxillary Artery - Inferior alveolar artery

Questions?

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