The document discusses the anatomy of teeth and surrounding structures. It describes how teeth are divided into crowns, necks, and roots. It outlines the five surfaces of each tooth and related terms. It details the four major tissues that make up teeth - enamel, dentin, cementum, and pulp. It also explains the periodontium, which includes structures that surround and support teeth like the periodontal ligament, alveolar bone, and gingiva. The goal is to identify and understand the divisions, surfaces, tissues, and surrounding structures of teeth.

2. Chapter 3
The Tooth and Its
Surrounding Structures

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Objectives
• At the completion of this chapter,
you will be able to
– Identify the divisions, surfaces and
tissues of the tooth and periodontium
– Describe location, composition, and
function of each tooth tissue and
surrounding structures

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Divisions of the Tooth
• Divided into three sections
– Crown is the visible portion of the tooth
covered in enamel
– Neck or cervix is where the crown joins the
root
• Also referred to the cemento-enamel junction
– Root is the nonvisible area, located at the
bone and covered in cementum

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Divisions of the Tooth

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Divisions of the Tooth
• As part of aging, bone and gingiva
recede and a portion of the root is
exposed
– When the crown and exposed root
are visible together it is referred to
as the clinical crown

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Divisions of the Tooth

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Surfaces of the Tooth
• Five surfaces each named
according to its position in the arch
–Mesial is the surface closest to the
midline
–Distal is the surface farthest/most
distant from the midline

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Surfaces of the Tooth
–Facial are the surfaces closest to the face
or outer surfaces of the teeth, including
• Labial: facial surfaces of the anterior teeth;
closest to the lips
• Buccal: facial surfaces of the posterior teeth or
surfaces closest to the cheek
–Lingual are surfaces closest to the tongue or
palate; all the inner surfaces

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Surfaces of the Tooth
–Occlusal are chewing surfaces
of the posterior teeth
–Incisal edge are biting surfaces
of the anterior teeth
–The tooth has either an occlusal
or incisal surface, they cannot
have both.

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Surfaces of the Tooth

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Related Terms
• Other terms that relate to the surfaces of the
teeth
– Proximal: surface that is next to adjacent tooth
– Interproximal: triangular space between adjacent
teeth filled with interdental papilla
– Contact area: both the mesial and distal surfaces
that touches the adjacent tooth

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Related Terms
– Apex: tip of the root
– Line angle: area of the tooth where two surfaces
meet
– Point angle: area of the tooth where three
surfaces meet
• When describing the precise location of a
tooth structure, divide the crown an root into
thirds

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Related Terms

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Related Terms

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Tissues of the Tooth
• Enamel: protective layer of the tooth
–Hardest tissue in body
• 96% inorganic, 4% organic matter and water
–Varies in thickness
• Cementum: covers the root
–Same density as bone
• 50% inorganic, 50% organic and water
–Can regrow itself

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Tissues of the Tooth
• Dentin is major portion of crown and
root
–Harder than bone
• 70% inorganic, 30% organic matter and
water
–Organic matrix of dentinal tubules
• Tubules filled with dentinal fibrils, carry
sensation from enamel to pulp

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Tissues of the Tooth
• Pulp
– Assists in production of dentin
– Located at innermost portion of tooth and is the
only soft tissue
– Pulp chamber in the crown and pulp canal in the
root make up the pulp cavity
– Vessels of pulp enter and exit through a small
apical foreman

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Tissues of the Tooth

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The Periodontium
• Structures that surround and support the
teeth
– Cementum is considered a support structure
containing fibers extending to the periodontal
ligament
– Periodontal ligament are fibers that support and
suspend the tooth in the alveolus or socket

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The Periodontium
–Alveolar process supports and
stabilizes the root, comprised of two
layers of bone tissue
• The inner lightweight, porous is the
cancellous or trabecular bone
• The compact or cortical bone is a more
dense layer structured to endure stress

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The Periodontium

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The Periodontium
–Gingiva is mucosa covered epithelial tissue
visible in the oral cavity; divided into two
sections
• Free gingiva: surrounds the cervix of the tooth
like a collar and fills the interproximal space.
– Unattached on inner surface, creating a space
called gingival sulcus
• Attached gingiva: paler pink and can be
observed on the external surface. Merges with
free gingiva at the free gingival junction

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The Periodontium

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• https://www.purposegames.com/game/t
ooth-surfaces-game
• https://www.animated-
teeth.com/questions-answers/kids-
tooth-anatomy/tooth-lesson-kids.html
• https://www.animated-
teeth.com/questions-answers/dental-
structures/dental-anatomy.html
Practice Exercise
25

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May not be scanned, copied, or duplicated, or posted to a publicly accessible web
Summary
• Integrity of the tooth depends on
the good health and stability of all
the periodontal tissues
• Together, they provide and
maintain the longevity of the
dentition and protect it from injury