BIOLOGY OF THE HUMAN DENTITION

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BIOLOGY OF THE HUMAN DENTITION
The innervation of teeth
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The innervation of teeth

• All nerves that innervate the teeth and gingivae
  are branches of the trigeminal nerve, the fifth
  Cranial Nerve, CN V
• The trigeminal Nerve has 2 roots
• The larger sensory root and
• The smaller motor root

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The innervation of teeth

• The larger sensory root immediately enlarges into
  a
• swelling called the trigeminal (semilunar)
  ganglion.
• Three large nerves arise from the trigeminal
  ganglion
• the ophthalmic nerve,
• the maxillary nerve, and
• the mandibular nerve

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The innervation of teeth
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The innervation of teeth
Ophthalmic nerve V1
Trigeminal ganglion
Maxillary nerve V2
Mandibular nerve V III
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The innervation of teeth
The upper parts of the oral cavity, including the
palate and the upper teeth, are innervated by
branches of the maxillary nerve CN V2 The
lower parts, including the teeth and oral part of
the tongue, are innervated by branches of the
mandibular nerve CN V3
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The maxillary nerve

• The maxillary nerve V2 is purely sensory.
• It leaves the skull by way of the foramen
  rotundum.
• In the pterygopalatine fossa it gives off a
  number of branches.
• It enters the inferior orbital fissure and the
  infra-orbital canal as the infraorbital nerve
  which supplies the skin of the cheek and lower
  eyelid.

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The maxillary nerve
All upper teeth are innervated by the superior
alveolar plexus formed by the posterior, middle,
and anterior alveolar nerves, which originate
directly or indirectly from the maxillary nerve
V2.
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The maxillary nerve
From the plexus, dental branches are given off to
each tooth root and interdental branches to the
bone, periodontal membrane and gingivae, the
distribution being similar to that described for
the arteries.
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The maxillary nerve
The posterior superior alveolar nerve originates
directly from the maxillary nerve V2 in the
pterygopalatine fossa. It enters the maxilla
through the alveolar foramen, and passes through
the bone in the wall of the maxillary sinus. It
innervates the molar teeth.
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The maxillary nerve
The middle superior alveolar nerves originate
from the infraorbital branch of the maxillary
nerve V2 in the floor of the orbit. They arises
from the infra-orbital nerve in the infra-orbital
groove, passes through the bone in the lateral
wall of the maxillary sinus, and innervates the
premolar teeth.
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The maxillary nerve
The anterior superior alveolar nerve originates
from the infraorbital nerve in the infra-orbital
canal, passes through the maxilla in the anterior
wall of the maxillary sinus, and via the superior
alveolar plexus, supplies the canine and incisor
teeth.
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The maxillary nerve
posterior superior
middle superior
Anterior superior
superior alveolar plexus
Denta peridental branches
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The maxillary nerve
The branches from the pterygopalatine ganglion,
which run a descending course and are distributed
as follows the greater and lesser palatine
nerves, which pass through the corresponding
palatine foramina to supply the mucous membrane
of the hard and soft palates, the uvula and the
tonsils.
Greater palatine nerve
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The maxillary nerve
The nasopalatine nerve supplies the nasal septum
then emerges through the incisive canal of the
hard palate to supply the incisive papilla and
the gum behind the incisor teeth.
Incisive nerve
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The mandibular nerve
The mandibular nerve is the third
division (branch) of the trigeminal nerve. It
passes through the foramen ovale and into the
infratemporal fossa. The mandibular nerve is
largely sensory but it also receives the motor
fibers (axons) from the motor root of CN V that
mainly supply the muscles of mastication.
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The mandibular nerve
Mandibular nerve V III
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The mandibular nerve
Almost immediately after passing through the
foramen ovale it breaks up into its several
branches.
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The mandibular nerve
Just before entering the mandibular foramen, it
releases the mylohyoid branch, which is a motor
branch to the mylohyoid muscle and anterior belly
of the digastric muscle.
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The inferior alveolar nerve

• The chief branch to the lower jaw is the inferior
  alveolar nerve.
• After entering the mandibular foramen on the
  medial surface of the ramus of mandible, it
  travels anteriorly through the bone in the
  mandibular canal.

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The inferior alveolar nerve
During this part of its course, it gives off
branches. Those dental and the interdental
branches, that form the inferior dental plexus,
supply molar and premolar teeth, alveolar bone,
periodontal membrane and gingivae.
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The inferior alveolar nerve

• Adjacent to the first premolar tooth, the
  inferior alveolar nerve divides into 2 branches
• the incisive branch, which innervates the first
  premolar, the canine, and the incisor teeth,
  together with the associated vestibular (buccal)
  gingiva

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The inferior alveolar nerve

• the mental nerve exits the mandible through the
  mental foramen and innervates the chin and lower
  lip.

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The mandibular nerve

• Other branches of the mandibular nerve are
• the buccal nerve, and
• the lingual nerve.

Denta peridental branches
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The innervation of supporting tissues
Like the teeth, the gingivae are innervated by
nerves that ultimately originate from the
trigeminal nerve V. Gingiva associated with the
upper teeth is innervated by branches derived
from the maxillary nerve V2 Gingiva
associated with the lower teeth is innervated by
branches of the mandibular nerve V3.
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The innervation of supporting tissues
The gingiva on the buccal side of the upper teeth
is innervated by the anterior, middle, and
superior alveolar nerves, which also innervate
the adjacent teeth. Gingiva on the palatal
(lingual) side of the same teeth is innervated
by the nasopalatine nerve innervates gingiva
associated with the incisor and canine teeth
the greater palatine nerve supplies gingiva
associated with the remaining teeth.
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The innervation of supporting tissues
The gingiva associated with the (buccal) side of
the mandibular incisor, canine, and premolar
teeth is innervated by the mental branch of the
inferior alveolar nerve. Gingiva on the buccal
side of the mandibular molar teeth is innervated
by the buccal nerve, which originates from the
mandibular nerve V3. Gingiva adjacent to the
lingual surface of all lower teeth is innervated
by the lingual nerve.
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