Oral Cavity – Its very important for each Dental Auxiliary staff member to know all the basic aspects about the procedures performed by a dentist, to work efficiently in a Dental Office. One needs to be familiar with dental terminology (words used to refer to the oral cavity different parts of the face, mouth, and teeth) because a dentist will use these terms regularly.
All this knowledge not only increases the communication ease but also makes the staff member more comfortable in understanding about how the parts and organs that make up the facial structure look and work. The anatomy of the oral cavity is quite complex, as it consists of several parts. The functions and a description of each of these Oral Cavity parts will be explored in this article. You all see how each part of the oral cavity has developed and how each function.
THE PALATE in oral cavity
The palate is often described as the “roof of the mouth or oral cavity”. This area makes up the superior (upper) portion of the oral cavity as well as the inferior (lower) portion of the nasal cavity. The palate itself is a long structure that is covered by several soft tissue components. The palate is divided into two major sections—the hard palate and the soft palate.
The Hard Palate
The hard palate (the bony portion of the mouth’s roof) is located in the anterior portion of the mouth or oral cavity. A thin epithelial tissue, known as the oral mucosa, covers it The oral mucosa is made of a dense, highly proliferating tissue that allows it to regenerate quickly.
There is an area in the anterior section of the hard palate that which is known as the palatine rugae. It is in the area where the mucosa folds into irregular ridges just behind the maxillary anterior teeth that the palatine rugae can be located. At the end of the palate is a common area that is utilized for both respiration and digestion. This area aids in both the passage of air for respiration and the swallowing of nourishment for digestion. This section of oral cavity is typically the beginning of the throat and is termed the pharynx.
Mouth (Oral Cavity)
The Soft Palate
The soft palate in oral cavity is located posterior to the hard palate. It is made of soft tissue, including muscle and oral mucosa. The function of the soft palate is to aid in the process of swallowing. The soft palate actually moves up and back to cover the nasopharynx (the portion located behind the nose, above the soft palate) when the swallowing mechanism is initiated. This motion prevents food items from entering the airway, thus preventing choking or aspirating (the breathing in of food particles). The soft palate consists of two main parts—the uvula and the tonsils.
The uvula in oral cavity is located at the edge of the soft palate, at the center of the entrance of the throat. It consists mainly of lymphatic tissue and assists the body in fighting systemic infections. The tonsils are located near the soft palate on both sides of the oropharnyx. The oropharnyx extends from the soft palate to the epi glottis, which keeps food from entering the larynx (the voice box). The oropharyrix is the part of the throat that you can see when you look into the mouth or oral cavity. The tonsils are also composed of lymphatic tissue and assist in fighting infections in the body.
The Gag Reflex
The gag reflex is produced in the oral cavity and is basically a protective action of the body. The action itself is produced within the soft palate, the orophamyx, and the posterior portion of the tongue. This region is covered by a very sensitive mucosa. Any time a foreign body enters this area, the body reacts by closing the posterior oral cavity in order to expel the object from the oral cavity. This action has been termed the gag reflex and is unique in the fact that it is completely involuntary and cannot be controlled.
SALIVARY GLANDS AND DUCTS in oral cavity
The salivary glands are located in the soft tissue surrounding the oral cavity. Their function is to secrete saliva, which is the first step in the process of digestion. Saliva is composed of various proteins manufactured by the salivary glands. Once saliva is made, it has three functions. It aids in digestion through enzymatic breakdown of food; it facilitates swallowing; and it cleanses food debris away from teeth and soft tissue structures.The salivary glands are divided into four functioning areas—the parotid, the submandibular, the sublingual, and minor salivary glands.
The Parotid Glands
The parotid glands are the largest of the salivary glands. The glands are located on both sides of the oral cavity, just in front of and below each ear. They extend to the lower angle of the mandible (lower jaw area) and are contained within the soft tissues of the cheek. The saliva manufactured by this gland is serous in consistency. It is liquid by nature and is mainly utilized for digestive purposes. The saliva is secreted through a tubule called Stensen ‘s duct. This duct opens into the mouth or oral cavity from the cheek just opposite the maxillary (upper jaw area) second molar.
The Submandibular Glands in oral cavity
The sub-mandibular glands are located below the posterior portion of the mandible. The saliva manufactured by these glands is very mucoserous in nature. They are termed the “mixed glands” because their saliva is a cross between a sticky mucous substance and a thin serous consistency. It is utilized for lubrication as well as digestion. These glands secrete saliva through a duct located in the lingual posterior area of the tongue.
The Sublingual Glandsin oral cavity
The sublingual glands are the smallest of the three major salivary glands. They are located in the lower anterior floor of the mouth or oral cavity, one on either side of the tongue. The secretions of these glands are mucous like in nature. The function of the secretion is mainly to aid in digestion. The ducts for secretion from these glands are located in the floor of the mouth or oral cavity, under the tongue.
Minor SalivaryGlands in oral cavity
Minor salivary glands are located throughout the oral cavity. They may be found on the buccal mucosa, palate, or lips. The secretion from these glands is of a mixed consistency. They secrete directly into the oral cavity without the use of any ducts. They are known as ductless glands.
THE TONGUE in oral cavity
The tongue, which is located on the floor of the oral cavity, is a very specialized set of muscles. It has many functions: it is involved in the action of speech, breathing, and mastication. It is very resilient and flexible in nature, as it consists of both a dorsal (top) portion called the dorsum, and a ventral (bottom) portion.
The Dorsal Surface of oral cavity
The dorsal surface (dorsum) of the tongue is covered with a thick, epithelial tissue covering. The taste buds can be found in the dorsal epithelium. It is interesting to note that there are separate taste buds for different food flavours. For example, there are different taste buds for sweet, salty, and sour flavours. The dorsum of the tongue also contains many valleys and ridges as a normal part of its anatomy.
The Ventral Surface of oral cavity
The ventral surface of the tongue is the underside of the tongue. This is where the tongue attaches to the floor of the mouth. The ventral portion of the tongue is covered by a very delicate and highly vascular epithelium. All of the nerve and blood vessels that supply the tongue are within the ventral aspect.
THE FRENUM of oral cavity
The frenum is a loose, fibrous connective tissue that is covered by oral mucosa. There are frena located on both the maxillary and mandible arches.
The Maxillary Labial Frenum in oral cavity
The maxillary labial frenum is located between the two front teeth known as the central incisors. The beginning of the frenum starts at the gingiva (gum tissue), passes through the oral mucosa, and ends on the inside (lingual) surface of the lip. The frenum gains significance only if it is attached too closely to the central incisors. In such a situation, it can cause a space between these two teeth, known as a diastema. The space can be closed through orthodontic work. However, before this can be accomplished with the use of braces, the frenum may be removed from this area. The frenum may cause the space to reopen if it is not treated correctly.
The Mandibular Labial Frenum in oral cavity
The mandibular labial frenum is located in the lower dental arch, between the two lower central incisors. It is composed of connective tissues. Like the maxillary labial frenum, it can cause a space between the two lower central incisors. Surgical removal is often required in such a situation. However, this procedure is performed less frequently than the maxillary labial frenum procedure. This frenum also begins its attachment in the gingiva and passes through the oral mucosa in order to insert itself into the inner surface of the lower lip.
The Mandibular Lingual Frenum in oral cavity
The mandibular lingual frenum is located underneath the tongue. It originates in the floor of the mouth and passes to the under surface of the mucosa. An abnormality of this frenum can cause a condition known as “tongue-tie.” This problem is caused when the frenum attachment limits movement of the tongue. It can be caused either by the frenum being too short or by the frenum being attached to the far anterior of the tongue. Either situation can cause a problem with both speech and swallowing functions. Correction of this problem can be achieved surgically by cutting the frenum in order to allow for free movement of the tongue.
The Buccal Frenum in oral cavity
The buccal frenum can be found on both the maxillary and mandibular arches. These are located in the area of the first premolars on both arches, passing from the gingiva to the inner surface of the cheek. It is very rare that the buccal frenum causes any oral problems or abnormalities.
THE TISSUES OF THE ORAL CAVITY
The Alveolar Ridge in oral cavity
The alveolar ridge, which supports the teeth in the jaw, can be found in both the maxillary and mandibular arches. It is the bony portion of the upper and lower jaw that houses the tooth sockets. This portion of bone is moderately dense and sponge-like in appearance. A more dense bone, known as the cortical plate, supports it. This plate has openings for the passage of vessels and nerves. This area makes up the body of the mandible. Since it is denser on the mandibles, it affects the injection of anesthesia.
A dense bone called the lamina dura, a section of the alveolar ridge, lines the tooth socket, The periodontal ligament, soft tissue that surrounds the tooth’s root and connects it with the bone of the socket wall of the tooth, is attached to the lamina dura.
The Periodontal Ligament in oral cavity
As already mentioned, the periodontal ligament is the soft tissue lining of the tooth socket. Its attachment runs from the lamina dura to the cementum of the tooth. Coarse bundles of fibrous tissue are embedded in the cementum, whose ends are termed Sharpey ‘s fibres. The periodontal ligament has three basic characteristics:
(A) It has specialized cells, which form the cementum, bone, and fibrous tissue specially adopted to support the tooth.
(B) It contains sensory fibres, which are stimulated upon percussion (striking or hitting force) and pressure.
(C) It helps hold the tooth firmly in the tooth socket.
There are five fiber groups of the periodontal ligament, each with its own location and function:
(1) The alveolar crest fibers are located at the height of the alveolar bone. Their function is to keep the teeth in their sockets and fight lateral forces.
(2) The horizontal fibers are located in the middle third of the tooth and run at right angles to the long axis of the tooth. Their primary purpose is to fight lateral tooth movement
(3) The oblique fibers are at an upward angle towards the coronal part of the tooth. They are located in the apical third (the anatomical area at the end) of the root. Their primary function is to resist axial forces (running length-wise) of the tooth. These fibers are the most numerous and make up the bulk of all fibers.
(4) The apical fibers can be found irregularly around the apex (end of the tooth root) of the tooth. Their purpose is the resistance of twisting forces. They also protect the blood and nerve supplies of the tooth.
(5) The interradicular fibres are located between the roots of teeth. They aid in the axial resistance as well as resistance to tipping.
THE GINGIVA in oral cavity
The gingiva (gum tissue) in oral cavity is the pink-colored tissue that surrounds the teeth and covers the alveolar mucosa. There are two types of gingiva—the free gingiva and the attached gingiva. The attached gingiva basically covers the alveolar mucosa. It is epithelial on the outside with connective tissue underneath. This gingiva is firmly attached to the underlying alveolar bone.
The free gingiva in oral cavity is composed of an epithelial surface with a connective tissue base. It surrounds the tooth buccally, lingually, and interproximally (between adjacent teeth). This tissue extends from the attached gingiva to the area where it attaches to the tooth. This attachment, known as the epithelial attachment, is located at the base of the gingival sulcus. The gin gival sulcus can be found next to the tooth and is formed by free gingival tissue. It is actually the area between the free gingiva and the tooth.
The depth of a healthy gingiva usually does not exceed two millimeters. This area of oral cavity is measured to determine gingival health. A deeper sulcus may indicate gingival inflammation and possibly periodontal disease (a general term for the many disorders of the gums). The free gingiva is a coral pink color while the attached gingiva is slightly redder. The difference is due to the fact that there is more vascularization in the attached gingiva. There is an area above the gingiva sulcus that is called the supra gingival area. This area includes all the structures of the oral cavity. The supragingival area is that area above the free gingiva and not in the gingival sulcus. The sub gingival is that area below the free gingiva and within the gingival sulcus.