BIOLOGY OF THE HUMAN DENTITION The innervation of teeth.

BIOLOGY OF THE HUMAN DENTITION

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

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


Mandibular nerve V III

Trigeminal ganglion

Ophthalmic nerve V1

Maxillary nerve V2


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];


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.

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].

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.

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.

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.

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.

The maxillary nerve

Anterior superior

middle superiorposterior superior

superior alveolar plexus

Denta & peridental branches

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

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

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.

The mandibular nerve


Mandibular nerve V III


Almost immediately after passing through the foramen ovale it breaks up into its several branches.


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.

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.


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.


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;


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


Other branches of the mandibular nerve are:

‾ the buccal nerve, and‾ the lingual nerve.

Denta & peridental branches

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].


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.


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.

Thank you very much

BIOLOGY OF THE HUMAN DENTITION The innervation of teeth.

Documents

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