Tooth Anatomy[1]New

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DENTAL ANATOMY

Dentistry- Branch of Medicine, which study teeth and associated structures of mouth;

It deals with prevention, diagnosis and treatment of diseases.

Stomatology- Studies teeth, dental arch and periodontal tissue, it constitutes the major objectives of thework that is done by a dentist in dental clinic.

Dental Anatomy- Field ofanatomy that focuses on the study of human tooth structures and theorganization of it. It is a base of all dental education.

Use-Legal

-For different branches of dentistry.

Major Elements in Dental Anatomy.

-Jaws-Teeth

-Muscles

-Nerves

-Blood supplies

-Lymphatics

JAW BONESTwo bones constitutes oral cavity . They bear teeth.

1.Upper Jaw (Mandible)2. Lower Jaw(Maxilla)

Mandible

Largest and only mobile bone of face.

Has two parts (body and ramus)

a. Body

The front and bigger part which constitute mentum (mental tuberosity). It is also called chin

>Mental foramen-Lies near the apex of second premolar.-Traverses vessels and nerves of lower anterior teeth (mental and incisive

branches).b. Ramus (Rami)Have two processes on upper end

a. codayloid process (mandibular condyle)-Composed of a condyle head and neck.

Lateral pterygoid muscle attached to front of the neck.

*TMJ(temporo-mandibular Joint) is the articulation between thecondyle of themandibleand the squamous portion of the temporal bone.

b. coronoid process- found more anteriorly-tendons of temporalis muscle inserted to anterior border.
http://en.wikipedia.org/wiki/Anatomyhttp://en.wikipedia.org/wiki/Anatomy


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Maxilla

Second largest bone of face. It is fusion of bones among median palatine (palatal) suture.

Hard Palate-Formed of right and left palatine processes.

>Incisive foramen- found on a midline, just posterior to central incisors.- transmits the anterior branches of the descending palatine artery and

nasopalatine nerve.

>Greater palatine foramina-posterior at the angle where the palatine bones and alveolarprocess of the hard palate meet, found near the second molar.

Maxillary SinusParanasal sinuses -Maxillary

-Frontal

-Ethmoid

-Sphenoid, found within respective bones.

Maxillary sinus is the largest of paranasal sinuses.Functions: - - Enlighten skull and increases the surface area

- Give resonance to voice- Warm and moisten inspired air and nasal cavity- Provide thermal insulation to the tissue above it- Filter debris from inspired air

Location:-Within body of each maxilla, right and left

Average size: - Transversely (width) - 2.5 cm-Anteroposteriorly3.5 cm

-Vertically3.2 cm

-Volume (capacity)15 mlShape: - 4sided (pyramidal)Blood, nerve supply and lymphatic is same as posterior teeth.

Epithelium: - Ciliated columnar, as respiratory tract.

Note:-Only 1-1.5 cm is there between Maxillary Sinus and apices of upper posterior teeth.

Sinus reaches its normal size at the age of 18.

OAF (oro-antral fistula) incidence increases on individuals less than 15 years old.

Muscles of Mastication

There are four(4) pairs to aid mastication(chewing).

- Masseter- Temporal

- Medial pterygoid

- Lateral pterygoid


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Nerves

Trigeminal Nerve (Vth cranial nerve)

is a nerve responsible for sensation in the face and certain motor functions such as biting, chewing, andswallowing. It is the largest of the cranial nerves. It is major sensory nerve of face and scalp. Its name

("trigeminal" = tri- or three, and -geminus or twin) derives from the fact that each trigeminal nerve, one oneach side, has three major branches: the ophthalmic nerve (V1), the maxillary nerve (V2), and the

mandibular nerve (V3). The ophthalmic and maxillary nerves are purely sensory. The mandibular nervehas both sensory and motor functions.

The ophthalmic nerve (V1) carries sensory information from the scalp and forehead, the

upper eyelid, the conjunctiva and cornea of the eye, the nose (including the tip of the

nose, except alae nasi), the nasal mucosa, the frontal sinuses, and parts of the meninges

(the dura and blood vessels).

The maxillary nerve (V2) carries sensory information from the lower eyelid and cheek,

the nares and upper lip, the upper teeth and gums, the nasal mucosa, the palate and roofof the pharynx, the maxillary, ethmoid and sphenoid sinuses, and parts of the meninges.

The mandibular nerve (V3) carries sensory information from the lower lip, the lowerteeth and gums, the chin and jaw (except the angle of the jaw, which is supplied by C2-

C3), parts of the external ear, and parts of the meninges. The mandibular nerve carries

touch/position and pain/temperature sensation from the mouth. It does not carry tastesensation (chorda tympani is responsible for taste), but one of its branches, the lingual

nerve, carries multiple types of nerve fibers that do not originate in the mandibular nerve.

> The motor branches of the trigeminal nerve control the movement of eight muscles,

including the four muscles of mastication
http://en.wikipedia.org/wiki/Nervehttp://en.wikipedia.org/wiki/Cranial_nerveshttp://en.wikipedia.org/wiki/Ophthalmic_nervehttp://en.wikipedia.org/wiki/Maxillary_nervehttp://en.wikipedia.org/wiki/Mandibular_nervehttp://en.wikipedia.org/wiki/Meningeshttp://en.wikipedia.org/wiki/Dura_materhttp://en.wikipedia.org/wiki/Nareshttp://en.wikipedia.org/wiki/Lingual_nervehttp://en.wikipedia.org/wiki/Lingual_nervehttp://en.wikipedia.org/wiki/Muscles_of_masticationhttp://en.wikipedia.org/wiki/Muscles_of_masticationhttp://en.wikipedia.org/wiki/Lingual_nervehttp://en.wikipedia.org/wiki/Lingual_nervehttp://en.wikipedia.org/wiki/Nareshttp://en.wikipedia.org/wiki/Dura_materhttp://en.wikipedia.org/wiki/Meningeshttp://en.wikipedia.org/wiki/Mandibular_nervehttp://en.wikipedia.org/wiki/Maxillary_nervehttp://en.wikipedia.org/wiki/Ophthalmic_nervehttp://en.wikipedia.org/wiki/Cranial_nerveshttp://en.wikipedia.org/wiki/Nerve


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TOOTH ANATOMYDentition- Collection of phenomena for formation, eruption and growth of teeth.

Humans have two sets of dentition/Teeth.20 primary / temporary / deciduous teeth.

32 permanent teeth.Temporary teeth start to shade in average at 6-7 and disappear from oral cavity all in all at the age of 10-12

years, which is replaced by permanent teeth. If there is no any accidental damage or disease, the permanentteeth remain for a lifetime.

The exchange between temporary and permanent teeth take place for a short period of time, approximatelybetween 6 and 12 years of age. During this period, the temporary and permanent teeth live in harmony in the

oral cavity intermix. This period of coexistence is known as mixed dentition.

The replacement of the temporary teeth by permanent teeth is normal physiological process withchronological order. It is not something spontaneous.

The temporary teeth use to hold the place for the permanent teeth.

Human has four types of teeth (Incisor, canine, premolar and molars). Thus called hetro-dent.

The three first temporary teeth are replaced by the same permanent teeth; the two primary molars

replaced by premolars. The permanent molars erupt on an open space behind the second

premolars as the jaws grow in size, they dont replace primary teeth.Structure of a typical tooth

A tooth consists of two main parts - the crown and the root.

Vertical section through a molar tooth showing internal structure


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The term "crown" of a tooth can be used in two ways.

The term "anatomic crown" of a tooth refers to the area above the cementoenamel junction (CEJ) or "neck"

of the tooth.[9]It is completely covered in enamel.

The term "clinical crown" often is convenient in referring to any part of the tooth visible in the mouth, but as

a rule the unqualified term "crown" refers to the anatomic crown. The bulk of the crown is composed of

dentin, with the pulp chamber within. The crown is enclosed within bone before the tooth erupts, but after

eruption the crown is almost always visible in an anatomically normal and clinically healthy mouth.

The anatomic root is found below the cementoenamel junction and is covered with cementum, whereas theclinical root is any part of a tooth not visible in the mouth. Similarly, the anatomic root is assumed in most

circumstances. Dentin composes most of the root, which normally has pulp canals. The roots of teeth may

be single in number (single-rooted teeth) or multiple. Canines and most premolars, except for maxillary first

premolars, usually have one root. Maxillary first premolars and mandibular molars usually have two roots.Maxillary molars usually have three roots. The tooth is supported in bone by an attachment apparatus,

known as the periodontium, which interacts with the root.

Surfaces

Surfaces that are nearest the cheeks or lips are referred to as facial, and those nearest the tongue are known

as lingual. Facial surfaces can be subdivided into buccal (when found on posterior teeth nearest the cheeks)

and labial (when found on anterior teeth nearest the lips). Lingual surfaces can also be described as palatalwhen found on maxillary teeth beside the hard palate.

Surfaces that aid in chewing are known as occlusal on posterior teeth and incisal on anterior teeth. Surfacesnearest the junction of the crown and root are referred to as cervical, and those closest to the apex of the root

are referred to as apical. The words mesial and distal are also used as descriptions. "Mesial" signifies a

surface closer to the median line of the face, which is located on a vertical axis between the eyes, down the

nose, and between the contact of the central incisors. Surfaces further away from the median line aredescribed as distal.

Cusp

A cusp is an elevation on an occlusal surface of posterior teeth and canines. It contributes to a significantportion of the tooth's surface. Canines have one cusp. Maxillary premolars and the mandibular first

premolars usually have two cusps. Mandibular second premolars frequently have three cusps--- one buccaland two lingual. Maxillary molars have two buccal cusps and two lingual cusps. A fifth cusp that may form

on the maxillary first molar is known as the cusp of Carabelli. Mandibular molars may have five or four

cusps.
http://en.wikipedia.org/wiki/Crown_(tooth)http://en.wikipedia.org/wiki/Cementoenamel_junctionhttp://en.wikipedia.org/wiki/Dental_anatomy#cite_note-8http://en.wikipedia.org/wiki/Dental_anatomy#cite_note-8http://en.wikipedia.org/wiki/Dental_anatomy#cite_note-8http://en.wikipedia.org/wiki/Tooth_eruptionhttp://en.wikipedia.org/wiki/Cheekhttp://en.wikipedia.org/wiki/Liphttp://en.wikipedia.org/wiki/Commonly_used_terms_of_relationship_and_comparison_in_dentistryhttp://en.wikipedia.org/wiki/Tonguehttp://en.wikipedia.org/wiki/Hard_palatehttp://en.wikipedia.org/wiki/Cusp_of_Carabellihttp://en.wikipedia.org/wiki/Cusp_of_Carabellihttp://en.wikipedia.org/wiki/Hard_palatehttp://en.wikipedia.org/wiki/Tonguehttp://en.wikipedia.org/wiki/Commonly_used_terms_of_relationship_and_comparison_in_dentistryhttp://en.wikipedia.org/wiki/Liphttp://en.wikipedia.org/wiki/Cheekhttp://en.wikipedia.org/wiki/Tooth_eruptionhttp://en.wikipedia.org/wiki/Dental_anatomy#cite_note-8http://en.wikipedia.org/wiki/Cementoenamel_junctionhttp://en.wikipedia.org/wiki/Crown_(tooth)


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Distinguishing characteristics of teeth

Incisor

There are two pairs of incisors in each jaw. There are two types; central and lateral incisors. Their

function is cutting and biting food. There are no cusps on the teeth. Instead, the surface area of the tooth

used in eating is called the incisal ridge or incisal edge which is chisel-like. They have a single root canalThough similar, there are some minor differences between the primary and permanent incisors.

Canine

There is a pair of canine in each jaw. Both the maxillary and mandibular canines are called the"cornerstone" of the mouth because they are all located three teeth away from the midline, and separate the

premolars from the incisors. The location of the canines reflect their dual function as they complement boththe premolars and incisors during chewing. Nonetheless, the most common action of the canines is tearing

of food. There is a single cusp and root canal on canines. They are well developed carnivorous animals.

Though similar, there are some minor differences between the deciduous and permanent canines.

Premolar

There are two pairs of premolars in each jaw. They are bigger than incisors and canines and areflattened on top with two cusps which aid chewing and grinding. They are also called bicuspid.They are divided into first and second premolars. The first pre-molar on the upper jaw has two rootcanals and all others have one. There are no deciduous premolars. Instead, the teeth that precede thepermanent premolars are the deciduous molars.

Molar

There are three pairs of molars in each jaw. Molars are also flattened on top. Molars are the mostposterior teeth in the mouth. Their function is to grind food during chewing. The number of cusps, and thus

the overall appearance, vary among the different molars and between people ranging from 3 to 5. Thenumber of the root canal is also variable. There are great differences between the deciduous molars and

those of the permanent molars, even though their functions are Despite being named "molars", the

deciduous molars are followed by permanent premolars. The third molars are commonly called "wisdom

teeth", which appears only much later in the adulthood and a specific description of a third molar willnot hold true in all cases.


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Other common terminologies

Apical - Part of a root that is far away from the crown.

Medial- Towards the center line

Lateral - Towards the sides of the body, either right or left

Division of crown and roots for description.

Horizontal: Crown - Incisal third, Middle third and cervical third.

Root - Apical cervical third, apical middle third and apical third.

Proximal: Crown - Mesial third, Middle third and distal third.

Root - Apical mesial third, apical middle third and apical distal third.

Buccal: Crown - Occlusal third, Middle third and cervical third.


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Tooth Glossary:

Crown - the visible part of a tooth, above the gum and root.

Root - the anchor of a tooth that extends into the jawbone, articulated to the dental alveoli. Thenumber of roots ranges from one to four.

Cervix-Neck portion of teeth or limit between the crown and the root

Cementum - a layer of tough, yellowish, bone-like tissue that covers the root of a tooth. It ismade up of mineral salts and water and is almost as hard as bone. It helps hold the toothin the socket. The cementum contains the periodontal membrane.

Dentinyellow, bone like, hard but porous tissue located under both the enamel and cementum

of the tooth. Dentin is harder than bone.

Enamel - the tough, shiny, white outer surface of the tooth. It is the hardest substance of human

body. I t can withstand high pressure.

Gums - the soft tissue that surrounds the base of the teeth.

Periodontal membrane/ligament - the fleshy tissue between tooth and the tooth socket; it holdsthe tooth in place. The fibers of the periodontal membrane are embedded within the cementum.

Pulp - the soft center and innermost layer of the tooth. The pulp contains blood vessels and nerves; it

nourishes the dentin.

Cingulum

A cingulum is a convexity mesiodistally resembels a girdle,encircling the lingual surface at the cervical third, foundon the lingual surface of anterior teeth. It is frequently identifiable as an inverted V-shaped ridge, and its

appearance is comparable to a girdle. All anterior teeth are formed from four centers of development, referred to as

lobes. Three are located on the facial side of the tooth, and one on the lingual side. The cingulum forms from this

lingual lobe of development. The majority of a lingual surface's cervical third is made up of the cingulum. On lower

incisors, a cingulum usually is poorly developed or absent. Maxillary canines have a large, well-developed cingulum,

whereas the cingulum of mandibular canines is smoother and rounded.

Ridges

Ridges are any linear, flat elevations on teeth, and they are named according to their location. The buccal

ridge runs cervico-occlusally in approximately the center of the buccal surface of premolars. The labialridge is one that runs cervico-incisally in approximately the center of the labial surface of canines. The

lingual ridge extends from the cingulum to the cusp tip on the lingual surface of most canines. The cervical

ridge runs mesiodistally on the cervical third of the buccal surface of the crown. These are found on allprimary teeth but only on the permanent molars.

Cusp ridges are ridges that radiate from cusp tips. There are two marginal ridges, mesial and distal, presenton all teeth. On anterior teeth, they are located on the mesial and distal borders of the lingual surface; on

posterior teeth, they are located on the mesial and distal borders of the occlusal surface. Triangular ridges

are those that project from the cusp tips of premolar and molars to the central groove. Transverse ridges are
http://en.wikipedia.org/w/index.php?title=Cingulum_or_girdle,also_may_be_denoted_as_the_lingual_lobe_of_an_anterior_teeth,whichmakes_the_cervical_third_of_the_lingual_surface_(tooth)&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Cingulum_or_girdle,also_may_be_denoted_as_the_lingual_lobe_of_an_anterior_teeth,whichmakes_the_cervical_third_of_the_lingual_surface_(tooth)&action=edit&redlink=1


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formed by the union of two triangular ridges on posterior teeth. The joining of buccal and lingual triangular

ridges is usually named as an example. The oblique ridge is found on the occlusal surfaces of maxillary

molars. It is formed by the union of the distal cusp ridge of the mesiolingual cusp and the triangular ridge ofthe distobuccal cusp. The oblique ridges usually forms the distal boundary of the central fossa.

Developmental groove

The teeth demonstrating the least number of developmental grooves are the mandibular central and lateralincisors. However, the canines show the most prominent developmental grooves, because they have strong

anchorage to the bone.

Embrasures

Embrasures are triangularly shaped spaces located between the proximal surfaces of adjacent teeth. The

borders of embrasures are formed by the interdental papilla of the gingiva, the adjacent teeth, and the

contact point where the two teeth meet. There are four embrasures for every contact area: facial (also calledlabial or buccal), lingual (or palatal), occlusal or incisal, and cervical or interproximal space. The cervical

embrasure usually is filled by the interdental papilla from the gingiva; in the absence of adequate gingival

tissue a black angle, or Angularis Nigra is visible.

Embrasures have three functions. They form spillways between teeth to direct food away from the gingiva.

Also, they provide a mechanism for teeth to be more self cleansing. Lastly, they protect the gingiva fromundue frictional trauma but also providing the proper degree of stimulation to the tissues.

Mammelons

Mammelons are usually found as three small bumps on the incisal edges of anterior teeth. They are theremnants of three lobes of formation of these teeth, the fourth lobe represented by the cingulum. Since this

surface of the tooth is the first to wear away from attrition, mammelons may not be visible on teeth of older

people. Instead, the best chance to see this characteristic is soon after eruption of the tooth into the mouth.Note, the presence of mammelons in adults is an indication of malocclusion.
http://en.wikipedia.org/wiki/Angularis_Nigrahttp://en.wikipedia.org/wiki/Mammelonhttp://en.wikipedia.org/wiki/Attrition_(dental)http://en.wikipedia.org/wiki/Attrition_(dental)http://en.wikipedia.org/wiki/Mammelonhttp://en.wikipedia.org/wiki/Angularis_Nigra


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TOOTH NOMENCLATURE (NOTATION)

On both dental arch upper and lower, the same teeth are presented in the same number. At the same time if

we draw a saggital line that can pass through the middle part of the oral cavity, each dental arch remains

divided in to two portions; right and left which are symmetrical. The divided 4 portions are called

quadrants in dentistry. They are: upper right, upper left, lower right and lower left quadrants.

The following are different types of tooth notation system.

1. Federation Dentierre Internationale (World Dental Federation)

It is the recent one and also called two digit system; as the first digit shows the number of the

quadrant (14 for permanent and 56 for primary) and the second number, the tooth. It is

officially accepted and used by WHO and FDI.

II. 18 17 16 15 14 13 12 11 21 22 23 24 25 26 27 28

31 32 33 34 35 36 37 38 41 42 43 44 45 46 47 48

I. I. 55 54 53 52 51 61 62 63 64 65

75 74 73 72 71 81 82 83 84 85

2. Zsigmondy Palmer (Palmer Notation)

Named after Hungarian Dentist called Adolf Zsigmondy, who developed the idea in 1861.

*ADA recommends Palmer notation system in 1947. It requires the use of symbols, which is

difficult on keyboard.

>Zsigmondy II. 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8

8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8

I. V IV III II I I II III IV V PalmerI. E D C B A A B C D E

V IV III II I I II III IV V E D C B A A B C D E

3. Universal System (American)

Common In America, then ADA supported it officially in 1968.

II. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

I. A B C D E F G H I J

K L M N O P Q R S T

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