Feline Dentistry. Jan Bellows
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and the palatoglossal folds extend to the soft palate at the base of the tongue (Figure 1.3).
The ventral tongue surface contains less cornified mucosa. The lingual frenulum connects the rostral two‐thirds of the tongue to the floor of the mouth within the intermandibular space.
1.5 Innervation
Sensory input is received from maxillary and mandibular divisions of the trigeminal nerve. The maxillary branch leaves the trigeminal ganglion, then exits the cranial cavity through the foramen rotundum, courses through the alar canal and the pterygopalatine fossa to enter the infraorbital canal. Just before entering the caudal limit of the infraorbital canal, the nerve branches into the major and minor palatine nerves. These nerves innervate the hard and soft palates and the nasopharynx. The palatine nerves are desensitized by the maxillary nerve block.
Figure 1.3 Caudal oral cavity.
The maxillary branch of the trigeminal nerve also branches out into the caudal maxillary alveolar nerve, which innervates the maxillary first molar, the buccal gingiva, and mucosa. This area is blocked by the infraorbital nerve block.
After giving off the caudal maxillary alveolar nerve, the maxillary nerve enters the infraorbital canal, where it is called the infraorbital nerve. While the infraorbital nerve is traversing the infraorbital canal, it gives off two more branches that exit ventrally from the canal. The middle maxillary alveolar nerve innervates the premolars and associated buccal gingiva. The rostral maxillary alveolar nerve supplies the canines, incisors, and associated buccal gingiva. The remaining fibers of the infraorbital nerve then exit the rostral extent of the infraorbital canal to innervate the lateral and dorsal cutaneous structures of the rostral maxilla and upper lip. The middle maxillary alveolar, rostral maxillary alveolar, and the infraorbital nerves are anesthetized by the rostral infraorbital nerve block.
The mandibular division of the trigeminal nerve arises from the trigeminal ganglion, exits the cranium via the foramen ovale, and divides into multiple branches. The divisions include the sensory buccal nerves, lingual nerve, and mandibular (inferior alveolar) nerve. The buccal nerves receive stimuli from the facial musculature, skin and mucosa of the cheek, and buccal gingiva along the caudal mandible.
The hypoglossal nerve innervates the tongue, the floor of the mouth, the lingual gingiva, and the mandibular salivary gland. The mandibular nerve enters the mandible on the lingual side, via the mandibular foramen. The nerve then courses rostrally within the mandibular canal to innervate the mandibular teeth to the midline. This nerve can be blocked by the mandibular (inferior alveolar) nerve block. Rostral to the third premolar tooth, the mandibular nerve gives off mental nerve branches. These branches exit through the mental foramina (rostral, middle, and caudal) and innervate the cutaneous areas of the chin and lip, and the rostral buccal gingiva and mucosa. These nerves are blocked by use of mental nerve blocks (usually the middle mental foramen is used).
1.6 Blood Supply and Lymphatic Drainage
The external carotid arteries branch out into the maxillary arteries. They further supply the mandibular (inferior alveolar) arteries, which enter the mandibular foramina on the medial sides of the mandibles and then course rostrally in the mandibular canals, where they exit through the mental foramina. The maxillary arteries also give rise to the major palatine arteries, which anastomose with the infraorbital arteries. The infraorbital arteries exit at the infraorbital foramina to supply the rostral muzzle. The lingual artery, a branch of the external carotid artery, supplies the tongue and mucosa of the floor of the oral cavity. The mandibular canal contains the inferior alveolar artery, vein, and nerve (the neurovascular bundle).
Lymph from the oral cavity drains into the parotid, mandibular, lateral, and medial retropharyngeal, superficial, and deep cervical lymph nodes. The mandibular lymph nodes are located rostral to the mandibular salivary gland. They are not lobulated like the salivary gland and therefore can be distinguished from them. They, along with the parotid lymph nodes, drain the entire head. They are more superficially located than the parotid lymph nodes and therefore are more easily palpated.
1.7 Salivary Glands
The major salivary glands in the cat include the parotid, zygomatic, mandibular, and sublingual. The mandibular salivary gland is located caudal to the ramus of the mandible and ventral to the parotid gland. The sublingual salivary gland lies in close approximation to the rostral aspect of the mandibular gland.
Saliva from the parotid gland exits at a papilla in the alveolar mucosa, just caudal to the maxillary fourth premolar. Saliva from the zygomatic gland exits at a papilla in the alveolar mucosa near the maxillary first molar. Saliva from the mandibular and sublingual glands enters the oral cavity through the sublingual caruncles located ventral and rostral to the base of the tongue (Figure 1.4) (Illustration 1.1).
Cats have four molar salivary glands. The buccal molar glands empty into the oral cavity through several small ducts. The lingual molar glands are located in the membranous molar pad linguodistal to the mandibular first molar teeth (Figure 1.5).
Figure 1.4 Sublingual caruncles.
Illustration 1.1 Cat salivary glands.
Source: Image courtesy of Tamara Rees, Veterinary Information Network.
Figure 1.5 Membranous bulge linguodistal to the mandibular first molar tooth containing a minor salivary gland (lingual molar gland).
1.8 Periodontium
The term periodontium or periodontal apparatus is used to describe tissues that surround and support the teeth, including the gingiva, periodontal ligament, cementum, and alveolar bone.
Figure 1.6 Oral mucosa in a patient with gingivitis, periodontitis, and caudal mucositis.
1.9 Gingiva
The cat's oral cavity is lined with keratinized and nonkeratinized stratified squamous epithelium. Gingiva refers to the keratinized oral mucosa that covers the alveolar process and surrounds the cervical portion of the tooth crowns. Unlike the epithelial lining of the digestive tract, the gingiva does not have absorptive capacity but acts as a physiologic permeable barrier that protects underlying structures from