dental anatomy and physiology 2009 welcome to ifdea3087

8/11/2019 Dental Anatomy and Physiology 2009 Welcome to Ifdea3087

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DENTAL ANATOMY &

PHYSIOLOGYPhysiology, Etiology, Epidemiology,

Diagnosis, and Treatment

Reviewed by:


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Dental Anatomy and Physiology

After viewing this lecture, attendees should be able to:

Identify the major structures of the dental anatomy

Discuss the primary characteristics of enamel, dentin, cementum, anddental pulp

Describe the biologic functions that take place within the oral cavity


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Primary (deciduous)

Secondary (permanent)

Definition (teeth): There are two definitions


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A tooth is made up of three elements:

Water

Organic materials

Inorganic materials

Elements


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Primary (deciduous)

Consist of 20 teeth

Begin to form during the firsttrimester of pregnancy

Typically begin erupting around 6months

Most children have a completeprimary dentition by 3 yearsof age


Dentition (teeth): There are two dentitions

1. Oral Health for Children: Patient Education Insert. Compend Cont Educ Dent.


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Secondary (permanent)

Consist of 32 teeth in most cases

Begin to erupt around 6 yearsof age

Most permanent teeth have eruptedby age 12

Third molars (wisdom teeth) are theexception; often do not appear untillate teens or

early 20s

Dentition (teeth): There are two dentitions

Mandible

Maxilla Incisors

Canine (Cuspid)

Premolars

Molars


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Classification of Teeth:

Incisors (central and lateral)

Canines (cuspids)

Premolars (bicuspids)

Molars


Identifying Teeth

Incisor Canine Premolar Molar


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Identifying Teeth2

Incisor Canine Premolar Molar

Incisorsfunction as cutting or shearing instruments for

food.

Caninespossess the longest roots of all teeth and arelocated at the corners of the dental arch.

Premolarsact like the canines in the tearing of food

and are similar to molars in the grinding of food.

Molarsare located nearest the temporomandibular joint

(TMJ), which serves as the fulcrum during function.


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Dental Anatomy

and Physiology

Apical Labial

Lingual

Distal

Mesial

Incisal

Teeth: Identification

Tooth Surfaces

Labial

Apical

Lingual

Distal

Apical

Mesial

Incisal Incisal


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Dental Anatomy

and Physiology

Apical: Pertaining to the apex or

root of the tooth

Labial: Pertaining to the lip;

describes the front surface ofanterior teeth

Lingual: Pertaining to the tongue;

describes the back (interior)

surface of all teeth

Distal: The surface of the tooth

that is away from the median line

Mesial: The surface of the tooth

that is toward the median line

Labial

Apical

Lingual

Distal

Apical

Mesial


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Enamel

Alveolar Bone

Pulp

Chamber


Enamel (hard tissue)

Dentin (hard tissue)

Odontoblast Layer Pulp Chamber (soft tissue)

Gingiva (soft tissue)

Periodontal Ligament (soft tissue)

Cementum (hard tissue)

Alveolar Bone (hard tissue)

Pulp Canals

Apical Foramen

The Dental Tissues: Dentin

Odontoblast Layer Gingiva

Periodontal Ligament

Cementum

Pulp Canals

Apical Foramen


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Anatomic Crown

Anatomic Root

Pulp Chamber

The 3 parts of a tooth:

Anatomic Crown

Anatomic Root

Pulp

Chamber



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Anatomic Crown

Anatomic Root

Pulp

Chamber


The anatomiccrownis the portion

of the tooth covered by enamel.

The anatomic rootis the lower two

thirds of a tooth.

The pulp chamberhouses the

dental pulp, an organ of myelinated

and unmyelinated nerves, arteries,

veins, lymph channels, connective

tissue cells, and various other cells.


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Structure

Highly calcified and hardest tissue inthe body

Crystalline in nature Enamel rods

Insensitiveno nerves

Acid-solublewill demineralize at a pHof 5.5 and lower

Cannot be renewed

Darkens with age as enamel is lost

Fluoride and saliva can help withremineralization


Dental TissuesEnamel2


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Dental TissuesEnamel2


Enamel can be lost by:3,4

Physical mechanism

Abrasion (mechanical wear)

Attrition (tooth-to-tooth contact)

Abfraction (lesions)

Chemical dissolution

Erosion by extrinsic acids (from diet)

Erosion by intrinsic acids (from the oralcavity/digestive tract)

Multifactorial etiology

Combination of physical and chemicalfactors


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Softer than enamel

Susceptible to tooth wear (physicalor chemical)

Does not have a nerve supply but canbe sensitive

Is produced throughout life

Three classifications Primary

Secondary

Tertiary

Will demineralize at a pH of 6.5 andlower

Dental TissuesDentin2



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Three classifications:

Primary dentinforms the initial shape of the tooth.

Secondary dentinis deposited after the formation of the primary dentin on all internal aspects ofthe pulp cavity.

Tertiary dentin, or reparative dentin is formed by replacement odontoblasts in response to

moderate-level irritants such as attrition, abrasion, erosion, trauma, moderate-rate dental caries,

and some operative procedures.

Dental TissuesDentin2



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Dentin

Pulp

Tubule

Fluid Nerve Fibers

Odontoblast

Cell

Dental Anatomy

and Physiology

Dental TissuesDentin (Tubules)2

Dentinal tubulesconnect the dentinand the pulp

(innermost part of the tooth, circumscribed by thedentin and lined with a layer of odontoblast cells)

The tubules run parallel to each other in an S-

shape course

Tubules contain fluid and nerve fibers

External stimuli cause movement of the dentinal

fluid, a hydrodynamic movement, which can result

in short, sharp pain episodes


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Association between erosion anddentin hypersensitivity3

Open/patent tubules

Greater in number

Larger in diameter

Removal of smear layer

Erosion/tooth wear

Enamel

Exposed

Dentin

Receding

Gingiva

Tubules

Odontoblast

Dental Anatomy

and Physiology

Dental TissuesDentin (Tubules)2


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Thin layer of mineralized tissuecovering the dentin

Softer than enamel and dentin

Anchors the tooth to the alveolarbone along with the periodontalligament

Not sensitive

Dental TissueCementum2


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Innermost part of the tooth

A soft tissue rich with blood vessels andnerves

Responsible for nourishing the tooth

The pulp in the crown of the tooth isknown as the coronal pulp

Pulp canals traverse the root of the tooth

Typically sensitive to extreme thermalstimulation (hot or cold)

Dental TissueDental Pulp2



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Pulpitisis inflammation or infection of the dental pulp, causing extreme sensitivity and/or pain.

Pain is derived as a result of the hydrodynamic stimuli activating mechanoreceptors in the nervefibers of the superficial pulp (A-beta, A-delta, C-fibers).

Hydrodynamic stimuli include: thermal (hot and cold); tactile; evaporative; and osmotic

These stimuli generate inward or outward movement of the fluid in the tubules and activate thenerve fibers.

A-beta and A-delta fibers are responsible for sharp pain of short duration

C-fibers are responsible for dull, throbbing pain of long duration

Pulpitis may be reversible (treated with restorative procedures) or irreversible (necessitating rootcanal).

Untreated pulpitis can lead to pulpal necrosis necessitating root canal or extraction.

Dental Tissue

Dental Pulp2,5



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Gingiva

Alveolar Bone


Cementum

Periodontal Tissues6


Gingiva

Alveolar bone

Cementum



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Gingiva:The part of the oral mucosa overlying

the crowns of unerupted teeth

and encircling the necks of erupted teeth,

serving as support structure forsubadjacent tissues.

Dental Tissue

Dental Tissue6


Gingiva


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Alveolar Bone:Also called the alveolar

process; the thickened ridge of bone

containing the tooth sockets in the mandible

and maxilla.

Dental Tissue

Dental Tissue6


Alveolar bone


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Periodontal Ligament:Connects the

cementum of the tooth root to the alveolar

bone of the socket.

Dental Tissue

Dental Tissue6




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Cementum:Bonelike, rigid connective tissue

covering the root of a tooth from the

cementoenamel junction to the apex and lining

the apex of the root canal. It also serves as anattachment structure for the periodontal

ligament, thus assisting in tooth support.

Dental Tissue

Dental Tissue6


Cementum


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Plaque

Saliva

pH Values

Demineralization

Remineralization

Oral Cavity/Environment7,8



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Dental Anatomy

and Physiology

Plaque:7,8

is a biofilm

contains more than 600 differentidentified species of bacteria

there is harmless and harmful plaque

salivary pellicle allows the bacteria toadhere to the tooth surface, which begins

the formation of plaque

Oral Cavity


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Dental Anatomy

and Physiology

Saliva:7,8

complex mixture of fluids

performs protective functions:

lubricationaids swallowing

mastication

key role in remineralization of

enamel and dentin

buffering

Oral Cavity


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Dental Anatomy

and Physiology

Demineralization:7,8

mineral salts dissolve into the

surrounding salivary fluid:

enamel at approximate pH of 5.5 or

lower

dentin at approximate pH of 6.5 or

lower erosion or caries can occur

Oral Cavity


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Dental Anatomy

and Physiology

Remineralization:7,8

pH comes back to neutral (7)

saliva-rich calcium and phosphates

minerals penetrate the damaged enamelsurface and repair it:

enamel pH is above 5.5

dentin pH is above 6.5

Oral Cavity


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Dental Anatomy & PhysiologyReferences

References

1. Oral Health for Children: Patient Education Insert. Compend Contin Educ Dent. 2005;26(5 Suppl 1):Insert.

2. Sturdevant JR, Lundeen TF, Sluder TB Jr. Clinical significance of dental anatomy, histology, physiology, and occlusion. In: Robertson TM,

Heymann HO, Swift EJ Jr, eds. Sturdevants Art and Science of Operative Dentistry . 4th ed. Mosby: St. Louis, MO; 2002:13-61.

3. Strassler HE, Drisko CL, Alexander DC. Dentin hypersensitivity: its inter-relationship to gingival recession and acid erosion.Inside

Dentistry. 2008;29(5 Special Issue):3-4.

4. Imfeld T. Dental erosion. Definition, classification and links.Eur J Oral Sci. 1996;104(2 (Pt 2)):151-155.

5. Dentin hypersensitivity: current state of the art and science. In: Pashley DH, Tay FR, Haywood VB, et al. Dentin Hypersensitivity:

Consensus-Based Recommendations for the Diagnosis and Management of Dentin Hypersensitivity.Inside Dentistry. 2008;4(9 Special

Issue):8-18.

6. Dorlands Medical Dictionary. 29thEd. Philadelphia, PA: W. B. Saunders Company; 2000.

7. Robertson TM, Lundeen TF. Cariology: the lesion, etiology, prevention, and control. In: Robertson TM, Heymann HO, Swift EJ Jr, eds.

Sturdevants Art and Science of Operative Dentistry . 4th ed. Mosby: St. Louis, MO; 2002:63-132.

8. Tooth Erosion in ChildrenUS Perspective.Inside Dentistry. 2009;5(3 Suppl):8.


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Dental Anatomy & Physiology

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