Mandibular Cuspid

The mandibular cuspid (figure 4-30) resembles the maxillary cuspid in many respects. The mandibular cuspid is long and firmly anchored in the alveolar bone. It occupies a key position in the dental arch. a. Facial Surface. The facial surface is narrower than the facial surface of the maxillary cuspid. The distal slope of the incisal margin is almost twice the length of the mesial slope. The mesial margin is almost parallel to the long axis of the tooth. Otherwise, the facial surface is much the...

Anatomic Differences Between Groups Of Teeth

The 32 teeth that are commonly found in the adult dentition have differences and similarities in form and function. For comparison, the teeth are often grouped as maxillary and mandibular teeth or as anterior and posterior teeth. a. Maxillary and Mandibular Teeth. The maxilla and the mandible contain the same number and types of teeth. There are certain distinct differences between the teeth of the two jaws. One of the differences is in the mesiodistal width between the maxillary and mandibular...

BAngles Junctions

The line angle is a line formed by the junction of two surfaces. A specific line angle is often named to indicate the surfaces it joins. For example, the junction between the distal and lingual surfaces of an anterior tooth is called the distolingual line angle. The junction between the mesial and the occlusal surfaces of a posterior tooth is called the mesio-occlusal line angle. There are eight line angles per tooth. (2) Point angle. The point angle represents the junction of...

Blood Supply Of The Jaws And Teeth

Arteries carry blood from the heart to the tissues of the body. The principal arteries supplying the head and the neck are the common carotid arteries. These arteries ascend within the tissues of the neck, one on the right side and one on the left side. See figure 2-14. (1) The internal carotid. At the level of the hyoid bone, each common artery divides into an internal carotid and an external carotid. The internal carotid supplies the tissues of the cranium and the eyes. (2)...

C Blood Vessels

Blood pumped by the heart is carried to the tissues through a system of elastic, hollow tubes called arteries (see figure 1-9). This system of arteries is like a tree with a large trunk. The arteries leave the heart and give off branches which repeatedly divide and become smaller and smaller. The arteries have a nerve supply controlled by the autonomic nervous system allowing them to enlarge or constrict. (2) Capillaries. The arteries branch into billions of tiny vessels called...

Circulatory System

The circulatory system includes the heart, blood, blood vessels (arteries, capillaries, and veins), and lymphatics. The function of the circulatory system is to circulate blood to the tissues of the body. These tissues supply oxygen and nutrients to the cells and remove carbon dioxide and other wastes. a. Heart. The heart is a muscular, cone-shaped organ (see figure 1-7). It continuously pumps blood to all parts of the body. It is divided into two separate halves, each forming a pump. Each half...

Credit Awarded

Upon successful completion of the examination for this subcourse, you will be awarded 15 credit hours. To receive credit hours, you must be officially enrolled and complete an examination furnished by the Nonresident Instruction Branch at Fort Sam Houston, Texas. You can enroll by going to the web site http atrrs.army.mil and enrolling under Self Development (School Code 555). A listing of correspondence courses and subcourses available through the Nonresident Instruction Section is found in...

CRounded Elevations

Lobes are one of the primary anatomical divisions of a crown. All teeth develop from either four or five lobes. Each lobe was the center of calcification in the developing tooth. Lobes are usually separated by readily identifiable developmental grooves. (2) Mamelon (scallop). A mamelon (see figure 4-9) is one of three small, rounded projections of enamel (thought to resemble a scallop shell) sometimes present on the cutting edge of a newly-erupted incisor tooth. The projections wear...

D Linear Elevations

A ridge is an elongated elevation of enamel on the crown surface of a tooth. Several different ridges can be found on a tooth. They are named for their location. (2) Marginal ridge. Marginal ridges (see figure 4-12) are elevations of enamel which form the mesial and distal margins of the occlusal surfaces of posterior teeth (on a bicuspid or a molar). They also form the mesial and distal margins of the lingual surface of anterior teeth (on an incisor or a cuspid). (3) Triangular...

Deciduous Teeth

The deciduous dentition is the common term used to designate the first set of a. Temporary Teeth or Primary Teeth. The terms temporary teeth or primary teeth are often used because these teeth are replaced by a permanent or second set early in life. The deciduous teeth are also called baby or milk teeth. The first of the deciduous teeth push through the gums (erupt) at an average age of 6 months. All deciduous teeth are usually erupted by the end of the second year. b. Description of the 20...

Division Of Teeth

To simplify the description of the surface anatomy of teeth, the crown and roots are divided into imaginary thirds. Each axial surface of the crown is divided into both vertical and horizontal thirds. The root is divided into horizontal thirds only. See figure 4-7. a. Each crown is divided into horizontal thirds--occlusal (or incisal), middle, and cervical (or gingival). b. Each mesial and distal surface of the crown is divided into vertical thirds-facial, middle, and lingual. c. Each facial...

E Depressions

A fossa (see figure 4-15) is a rounded or wedge-shaped (1) Fossa. A fossa (see figure 4-15) is a rounded or wedge-shaped (2) Sulcus. A sulcus (see figure 4-16) is an elongated depression (or valley) on the surface of a tooth. It is formed by the inclines of adjacent cusps or ridges. The sulcus has a developmental groove at the junction of its inclines (at the bottom). (3) Groove. A groove is a linear depression on the surface of a tooth. Grooves are formed by the union of two lobes...

Exercises Lesson

INSTRUCTIONS Answer the following exercises by marking the lettered response that best answers the question, or by completing the incomplete statement, or by writing the answer in the space provided at the end of the question. After you have completed all the exercises, turn to Solutions to Exercises at the end of the lesson, and check your answers. For each exercise answered incorrectly, reread the material referenced after the answer. 1. What is the meaning of topography of the mouth b....

Face

The face is an extremely important part of the anatomy. It has a wide range of attributes which involve your appearance and essential activities, such as swallowing, seeing, and breathing. Many tissues of the face are involved in dental treatment, and the dental specialist must have a thorough understanding of this anatomical area. Since the bones of the jaws (the maxilla and the mandible) are of special interest in dentistry, they are considered in separate paragraphs. Other bones are...

Integumentary System

The integumentary system includes the skin, a double-layered structure covering the surface of the body, and accessory organs such as glands, hair, and nails (see figure 1-2). The skin is the largest organ of the body. It functions to protect inner tissues from drying (desiccation) and underlying structures from infection and injury. Although absorption is not one of its normal functions, the skin can absorb water and other substances. The skin contains sensory receptors for heat, cold, touch,...

Mandibular First Bicuspid

The mandibular first bicuspid (figure 4-31) is the smallest tooth in the bicuspid group. It possesses characteristics of all bicuspids but it differs greatly in form, particularly when compared to upper bicuspids. a. Facial Surface. The facial surface is symmetrical in outline and more convex in all directions than are the upper bicuspids, giving the crown a form resembling an inverted bell. The two developmental grooves and the facial axial ridge are usually prominent. The facial cusp is long...

Mandibular First Molar

The mandibular first molar is the largest tooth in the mandible (see figure 4-33). It has five functional cusps, each of which develops from a separate lobe. The maxillary and mandibular first molars are often called six-year molars because of the age at which they erupt. Eruption of the mandibular teeth usually precedes that of the maxillary teeth by several months. This tooth plays a vital role in the establishment and maintenance of occlusion. It is called the key to occlusion. Figure 4-33....

Mandibular Lateral Incisor

The mandibular lateral incisor (figure 4-29) resembles the mandibular central incisor and the maxillary lateral incisor in many respects. The mandibular lateral incisor is slightly larger in all dimensions and is less symmetrical in outline. Figure 4-29. Mandibular right lateral incisor. Figure 4-29. Mandibular right lateral incisor. a. Facial Surface. From the facial view, the facial surface of the incisal edge slopes distally while the central incisor is straight. The mesioincisal angle is...

Mandibular Second Bicuspid

The mandibular second bicuspid (figure 4-32) is slightly larger, stockier, and less rounded than the mandibular first bicuspid. It is, however, more rounded or ovoid (egg-shaped) than the maxillary bicuspids and may have two or three cusps. The three-cusp form has two lingual cusps and one facial cusp. a. Facial Surface. The facial surface resembles the facial surface of the first bicuspid. b. Lingual Surface. The lingual surface is similar in outline to the facial surface. The lingual surface...

Mandibular Second Molar

The mandibular second molar (figure 4-34) is smaller than the mandibular first molar but is similar in general appearance. Cusps are usually four in number, but occasionally there are five. They are arranged similarly to those of the mandibular first molar. Because of the age at which they erupt, they are sometimes called the twelve-year molar. Figure 4-34. Mandibular right second molar. a. Facial Surface. The facial surface is rectangular in shape and convex in form. Its occlusal margin...

Mandibular Third Molar

The mandibular third molar (figure 4-35) is commonly known as the wisdom tooth. It may appear in any of a wide range of forms, sizes, and shapes. Typically, it resembles either the first or second mandibular molar (more often the latter). It is smaller in its overall size. Abnormalities of eruption and occlusion of third molars commonly occur. Figure 4-35. Mandibular right third molar. Figure 4-35. Mandibular right third molar.

Maxillary Central Incisor

The maxillary central incisor (figure 4-20) is located adjacent to the midline (median line) on the anterior portion of the maxillary dental arch. Its mesial surface contacts the mesial surface of the maxillary central incisor of the opposite side. This tooth has the greatest mesiodistal width of all anterior teeth. Like all anterior teeth, it develops from four fused lobes. Three of these lobes making up the facial surface and the fourth forming the cingulum on the lingual surface. Newly...

Maxillary First Bicuspid

The maxillary first bicuspid (figure 4-23) has the largest crown of the four maxillary bicuspid teeth. It is formed from four developmental lobes--three lobes form the facial cusp and one lobe forms the lingual cusp. a. Facial Surface. The facial surface resembles the facial surface of the maxillary cuspid but is not as long or as broad. b. Lingual Surface. The lingual surface is oval in shape and convex in all directions. It is shorter and narrower than the facial surface. Figure 4-23....

Maxillary First Molar

The maxillary first molar (see figure 4-25) is the largest tooth in the mouth. It develops from four lobes and is often called the six year molar because of the age at which it erupts. a. Facial Surface. The facial surface is convex in all directions. A groove (the facial groove) passes vertically from the middle of this surface, between the two facial cusps, and onto the occlusal surface. The mesiofacial cusp is higher and wider than is the distofacial cusp. b. Lingual Surface. The lingual...

Maxillary Lateral Incisor

The maxillary lateral incisor (figure 4-21) is smaller in size than the central incisor but has the same general appearance. It presents a generally greater convexity in its crown portion than does the central incisor. The maxillary lateral incisor can be compared with the central incisor in many ways. a. Facial Surface. The facial surface is similar in appearance to the central incisor but more convex (rounded) in form. Developmental grooves are not as pronounced as in the central incisor. b....

Maxillary Second Molar

The maxillary second molar (figure 4-26) is very similar to the maxillary first molar. There are some differences. It is smaller in all dimensions than the first molar. The fifth cusp is seldom present. The distolingual cusp is proportionally smaller. The mesiofacial and distofacial roots are occasionally fused. Figure 4-26. Maxillary right second molar.

Mucous Membrane

The mouth, nose, sinuses, eyelids, throat, and digestive tract are lined with mucous membrane. The mucous membrane lining the oral cavity is called oral mucosa. It covers the inside of the cheeks and lips and the bony process (alveolar process) in which the teeth are embedded. This covering of the alveolar process (which surrounds the necks of the teeth) is called the gingiva or gum tissue. Oral mucosa serves as a protective covering for the soft tissues of the mouth, much like skin protects...

Muscles Of Mastication

Four pairs of muscles are considered the major muscles of mastication. These muscles are used for chewing and swallowing food. The masseter, the temporalis, and the medial pterygoid raise the mandible against the maxilla with considerable force. The fourth pair of muscles, the lateral pterygoids, act to thrust the mandible forward. Acting with other muscles, it opens the mouth. See figures 2-9, 2-10, and 2-11. a. Masseter. The masseter is one of the primary muscles that close the jaws and...

Nervous System

This system includes a group of organs which controls and integrates the intellectual and physical processes of the individual. The nervous system is made up of nerve tissues. The main structure of the conductive nerve tissues is the neuron, a specialized cell designed to conduct electrical impulses. The nervous system is divided into the central nervous system, the peripheral nervous system, and the autonomic nervous system. a. Central Nervous System. The central nervous system includes the...

Numbering Of Teeth

Several systems of numbering the teeth have been devised to simplify the designation of a tooth by an authorized number rather than by name. The system used by the armed services (see figure 4-4) begins with the maxillary right third molar and numbers around the maxillary arch from 1 to 16. It continues with the mandibular left third molar as No. 17 and goes around the lower arch from 17 to 32. By this method, the number alone designates the tooth without the use of letters R and L. For...

Periodontal Ligament

The periodontal ligament is a thin, fibrous ligament connecting a tooth to the lamina dura of the bony socket. Normally, teeth do not contact bone directly. A tooth is suspended in its socket by the fibers of the ligament. Because of this arrangement, each tooth is capable of limited individual movement. The fibers act as shock absorbers to cushion the force of chewing impacts. The periodontal ligament also supplies nutrition to the alveolar process. It supports and attaches the gingiva. It...

Permanent Teeth

There are 32 permanent teeth, 16 in the maxilla and 16 in the mandible (see figure 4-4). The permanent teeth on the right side of the mouth, for example, are named as follows central incisor and mandibular right central incisor. lateral incisor and mandibular right lateral incisor. first bicuspid and mandibular right first bicuspid. second bicuspid and mandibular right second bicuspid first molar and mandibular right first molar. second molar and mandibular right second molar. third molar and...

Replacement Of Deciduous Teeth

The 10 deciduous teeth of each jaw are replaced by the 10 most anterior teeth of the permanent dentition (see figure 4-3) as follows (1) The permanent central incisors replace the deciduous central incisors. (2) The permanent lateral incisors replace the deciduous lateral incisors. (3) The permanent cuspids replace the deciduous cuspids. (4) The permanent first bicuspids replace the deciduous first molars. (5) The permanent second bicuspids replace the deciduous second...

Respiratory System

This system includes the lungs and a branched air passage leading into them. This passageway consists of the nose (or the mouth), pharynx, larynx, trachea, and two bronchi (see figure 1-15). The bronchi stem from the trachea (or windpipe). One bronchus passes into each lung. Within the lungs, the bronchi branch into smaller tubes. These tubes branch and rebranch many times to form a system of tiny air tubules. These tubules, called bronchioles, go to all parts of the lungs. They end in tiny air...

Salivary Glands

The three major pairs of salivary glands are the parotid glands, the submandibular glands, and the sublingual glands (see figure 2-17). They empty their secretions (saliva) into the oral cavity. The functions of saliva are cleansing, lubricating, promoting taste, and converting starches into simple sugar. The consistency, chemical composition, and rate of flow of saliva are contributing factors to potential diseases or abnormalities. a. Parotid Glands. These glands are the largest of the three...

The Oral Cavity

The oral cavity is bounded in front (anteriorly) and on the sides (laterally) by the gingival and lingual surfaces of the teeth. It opens posteriorly into the pharynx, which is a funnel-shaped space joining the nose and mouth with the passages (trachea and esophagus), leading to the lungs and stomach. a. Roof of the Mouth. The roof of the mouth is shaped like a vault (arched). It consists of the hard palate, anteriorly, and the soft palate, posteriorly, which together are called the palate. The...

Tissues Of The Teeth

Enamel is the calcified substance that covers the entire crown of the tooth. It consists of approximately 96 percent inorganic (nonliving) material and it is the hardest tissue in the human body. Enamel is thickest at the top of the teeth (at the cusps), thinning to a knife edge thickness where the crown and root join (the cervical line). Enamel is formed only once and cannot regenerate or repair itself. Thus, when enamel is destroyed by decay, operative dentistry is required to...

Maxillary Cuspid

The maxillary cuspid (figure 4-22) is the third tooth from the median line. It is the longest and the only single-cusp tooth in the arch. Located at the angle between the anterior and the posterior portions of the dental arch, it plays an important role in determining facial features of the individual and in controlling mandibular movement. It is sometimes called the canine tooth or eye tooth. Figure 4-22. Maxillary right cuspid. Figure 4-22. Maxillary right cuspid. a. Facial Surface. The...

Oral Vestibule

The space between the front teeth and the lips forms the anterior part of the oral vestibule. The posterior part of the oral vestibule can be explored by clenching the teeth, pulling the lips apart, and pushing the index fingers back along the surface of the teeth, moving them as far up and down as possible. Figure 3-1 shows a cross-section of the mouth. One of the principal uses of the mouth is human speech. These specialized sounds are made by using the lips, the teeth, the bony ridge back of...

Section Iii Mandibular Teeth 418 Mandibular Central Incisor

The mandibular central incisor (figure 4-28) is located adjacent to the median line in the anterior portion of the mandibular dental arch. Its mesial surface contacts the mesial surface of the central incisor of the opposite side. It is the smallest and most symmetrical of all teeth. Developmental grooves are indistinct. a. Facial Surface. The facial surface is flat in the incisal two-thirds and convex in the cervical third. It is widest near the incisal edge. The incisal edge forms a straight...

Parts Of Teeth

Each tooth is divided into the crown and the root (or roots) (see figure 3-4). The crown is that part of the tooth which is covered by enamel. The term clinical crown is often used to refer to that part of the tooth which is visible in the mouth. It seldom conforms exactly to that part covered by enamel. In this subcourse, the term crown will refer to the anatomic crown or that portion of the tooth actually covered by enamel. That portion of the tooth where the crown and the root join...

Upper Jaw Maxilla

The upper jaw (maxilla) is an irregular bone formed from the right and left maxillary bones, which unite along the midline of the face (see figure 2-2). It joins in the palate (roof of the mouth) at the intermaxillary suture or at the median palatal suture. The maxilla is considered the key to the architecture of the face. All the bones of the face, except the mandible, come in direct contact with the maxilla, that is, they have sutural contact. The maxilla consists of a body which gives shape...

BPeripheral Nervous System

Muscular System Diagram

The peripheral nervous system consists of the cranial and spinal nerves and their branches (see figure 1-14). Twelve pairs of cranial nerves have their roots in the brain. These nerves give off branches to the structures of the head and face. Thirty-one pairs of spinal nerves have their roots in the spinal cord. They give off branches to the structures of the body from the neck down. Each nerve supplies a specific body area or structure (called innervations). Because many of the...

Surfaces Of Teeth

Lingual Facial

For convenience of description and as an aid in denoting the location of areas of decay and restorations, the crown part of a tooth is divided into a number of surfaces. Some of these surfaces are characterized by certain anatomic features such as pits, grooves, and ridges. Every dental specialist should be familiar with these terms. These surfaces are named to indicate the direction each surface faces. See figure 4-5. a. Lingual. The lingual surface is that surface of the tooth that faces...

Urogenital System

This system, also called genitourinary system, includes the organs that eliminate urinary wastes from the body and the organs of reproduction (see figure 1-16). The urinary organs include the kidneys, ureters, bladder, and urethra. The kidneys are located on each side of the spine, just above the small of the back. They filter wastes from the bloodstream. These wastes pass into the ureters as urine. The ureters are thin, muscular tubes which lead to the bladder. The bladder is a muscular organ...

Nerve Supply Of The Jaws And Teeth

Nerve Supply Teeth

Twelve pairs of cranial nerves arise in the brain and give off branches to the structures of the head and face. These nerves leave the cranial cavity through foramina in the base of the cranium. The fifth cranial nerve the trigeminal nerve is the largest of the twelve pairs. See figure 2-13. It is of particular importance in dentistry since it provides the nerve supply to the jaws and the teeth. The fifth cranial nerve contains both motor and sensory fibers. Thus, it has a motor root supplying...