2. Tooth Structure
Teeth are made of hard tissues that
protect the pulp located in the
middle
Each tooth is comprised of four
primary structures
Enamel
Dentin
Cementum
Pulp
3. Enamel
Covers the outside of the crown
the hardest and most highly mineralized substance of the
body
96% of enamel consists of mineral
Can be very brittle if not supported by dentin and a vital
pulp
Thicker on occlusal cusps, 2.5mm
Ameloblasts aid in developing enamel rods, which are the
basic units of tooth enamel
4. Enamel continued…
The normal color of enamel varies from light yellow to grayish white
since enamel is semi-translucent, the color of dentin and any restorative
dental material underneath the enamel strongly affects the appearance of a
tooth
Enamel does not contain any blood vessels or nerves
Therefore, enamel damage is painless
Enamel can be stained
coffee, tea, tobacco and other food dyes, especially in case of poor oral
hygiene
Over time, it wears off, a process called attrition or abrasion
5. Enamel Dysplasia
A loss of nutritional support may result in the surface of the teeth
becoming grooved and pitted
The patient may be concerned with the appearance of the tooth,
and the weakened surface is more susceptible to decay
6. Dentin
The substance between enamel or cementum and the pulp
chamber
It forms the highest portion of the tooth and it normally has a gray-
white or yellowish color.
Odontoblasts form dentin
Dentin has microscopic channels, called dentinal tubules, which
radiate outward through the dentin from the pulp cavity to the
exterior cementum or enamel border.
Because it is softer than enamel, dentin decays more rapidly and is
subject to severe cavities if not properly treated, but it still acts as a
protective layer and supports the crown of the tooth
7. Dentinal Hypersensitivity
Patients may experience this if the dentin is exposed
May be very painful for the patient
In some individuals, the enamel and cementum do not come
together at the cementoenamel junction (CEJ), leaving exposed
dentin
Using the air-water syringe in an area that is not anesthetized causes
discomfort
8. Cementum
A specialized bone like substance covering the root of a
tooth, thicker at the apex
Its coloration is yellowish and it is softer than either dentin
or enamel
Continues to develop throughout life
Formed by cementoblasts
9. Cementum Continued
The principal role of cementum is to serve as a medium
by which the periodontal ligaments can attach to the
tooth for stability
In case of gingival recession, the gum retracts from the
tooth leaving part of the roots exposed. In these areas,
cementum is very sensitive to external stimuli (hot, cold)
10. Hypercementosis
When the tooth is traumatized due to force from the
occlusal or incisal surface
This causes a thickening of cementum around the apex,
which may show on the x-ray as a mass at the apex
11. Pulp
Also called "the nerve" of the tooth
Evolves from cells similar to the dentin
Function is to provide nourishment, support, and maintenance for
the dentin
Identifies the temperature and chemical changes, vibrations, and
bacterial invasion of the tooth and transmits this information to the
brain
Warning system that works as a defense system for the tooth
Pulp is fed continually through the opening at the apex of the root,
the apical foramen
12. Pulpitis
When the pulp is damaged due to
an injury, the tissue may become
inflamed
Pressure increases and cannot
escape
The structures of the tooth from a
hard encasement and, when the
tooth becomes inflamed, cause a
great deal of pressure and
discomfort
The patient may need to have root
canal therapy (RCT), which opens
the pulp and release the pressure
14. Periodontium
Consists of portions of the tooth structure that support hard
and soft dental tissues and the alveolar bone
The cementum is part of the periodontium as well as the
tooth structure
Helps to attach the tooth to surrounding tissues and to
allow sensations of touch and pressure
The word comes from the Greek terms peri, meaning
"around" and odons, meaning "tooth." Literally taken, it
means that which is "around the tooth"
15. Components of the Periodontium
Cementum
Alveolar Bone
Periodontal Ligament
Gingiva
16. Cementum
A specialized calcified substance covering the root of a tooth
It is the part of the periodontium that attaches the teeth to the
alveolar bone by anchoring the periodontal ligament
Sharpey’s fibers act as anchors between the alveolar bone and the
tooth (attached in the cementum and alveolar bone)
Cementum is formed continuously throughout life because a new
layer of cementum is deposited to keep the attachment intact as the
superficial layer of cementum ages
It has a light yellow color and the highest fluoride content of all
mineralized tissues
17.
18. Alveolar Bone
Bones of the mandible and maxilla are formed by
osteoblasts
Cells that remodel and resorb bone are called osteoclasts
Extended areas of bone in each arch that are tooth bearing
are called the alveolar process
Bone that surrounds the root of the tooth, the socket, is the
alveolus
The alveolus does not actually contact the root because the
periodontal ligament suspends it in place
19. Alveolar Bone continued….
The compact bone plates on the facial and lingual
surfaces are called the cortical bone
The alveolar crest is where two cortical bone places
come together between each tooth
If the tooth has multiple roots, the bone that separates
the roots is identified as the interradicular septum
20.
21. Alveolar Bone
Periodontal disease can cause bone loss
The bone does not regenerate and the diseased tissue must be
removed
Bone is stimulated from mastication and speech
If the teeth are removed, this stimulation is lost and the bone can resorb
The bone supports the teeth and the teeth support the bone
Modern implants placed in the bone are more successful if proper
dental hygiene of the are is maintained
The implant has no movement in the bone; unlike teeth, it remains stable
22. Periodontal Ligament
Formed by the fibroblast cells
Secures with tooth in the socket
by a number of organized fiber
groups
Two types of nerves
One sensory
One to regulate the blood vessels
Wider at CEJ (cementoenamel
junction) and at the apex
23. Periodontal Fiber Groups
Organized bundles or groups
These fibers allow for some flexibility during
mastication, speech, and other forces that
would be exerted on the teeth
24. Periodontal Fiber Groups
6 Principal fiber groups
1. Alveolar Crest Fiber Groups
2. Horizontal Fiber Groups
3. Oblique Fiber Groups
4. Apical Fiber Groups
5. Interradicular Fiber Groups
6. Interdental (or Transseptal) Ligament Groups
25. Alveolar Crest
Fiber Groups
Function: to resist rotational
forces and tilting
Attachment: originate in the
alveolar crest of the alveolar
bone and then insert into the
cervical cementum at various
angles
26. Horizontal Fiber
Groups
Function: to resist rotational
forces and tilting
Attachment: Originate in the
alveolar bone, apical to the
alveolar crest, and then insert
into the cementum
horizontally
27. Oblique Fiber
Groups
Function: resist intrusive forces
that try to push the tooth
inward
Attachment: In the alveolar
bone and extending in an
oblique (diagonal) manner into
the cementum
Most abundant of the fiber
groups
Cover 2/3 of the root
28. Apical Fiber
Groups
Function: resist forces that try
to pull the tooth outward, as
well as rotational
Attachment: attach at the
apex and radiate outward to
attach in the surrounding
alveolar bone
29. Interradicular Fiber
Groups
FOUND ONLY IN MULTIROOTED
TEETH
Function: resist rotational forces
and to hold the teeth in
interproximal contact
Attachment: They run from the
cementum to interradicular bone
Definition on Page 150 is wrong
30. Interdental (or transseptal)
Ligament Groups
Function: to resist rotations
forces and hold teeth in
interproximal contact
Attachment: They run above
the crest of the alveolar bone
interdentally, from the cervical
cementum of one tooth to the
cervical cementum of another
tooth
31.
32. Clinical Considerations Regarding the
Periodontal Ligaments
Occlusal trauma does not cause periodontal disease but can
accelerate an existing disease
Chronic periodontal disease causes the fiber groups to become
disorganized and lose attachment due to resorption
The fiber group that is retained the longest during periodontal
disease is the interdental ligament. As the disease progresses,
this ligament reattaches itself in a more apical manner
33. Gingival Fiber Groups
Found in the lamina propria
The connective tissue of the marginal gingiva
Support the marginal gingival tissues in relationship to
the tooth
34. Gingival Fiber Groups
1. Dentogingival Fiber Groups
2. Circular ligament Fiber Groups
3. Alveologingival Fiber Groups
4. Dentoperiosteal Fiber Groups
35. Dentogingival Fiber Groups
Function: Maintain the
gingival integrity of the
marginal gingiva
Attachment: They
attach to the
cementum and extend
into the lamina propria
of the marginal gingiva
36. Circular Ligament
Fiber Groups
Function: Circle and
tighten the gingival margin
around the neck of the
tooth
Attachment: In the lamina
propria of the marginal
gingiva
37. Alveologingival
Fiber Groups
Function: Aid in attaching
the gingiva to the alveolar
bone
Attachment: Extend from
the alveolar bone and
diffuse into the overlying
lamina propria of the
marginal gingiva
38. Dentoperiosteal Fiber Groups
Function: Anchor the
tooth to the bone
Attachment: From the
cementum, near the CEJ,
and extend across the
alveolar crest
39. Gingiva
Composed of mucosa that surrounds the necks of the teeth
and covers the alveolar processes
Commonly called the gums
Can be attached to the underlying bone or unattached
In a healthy state, it is frim and tightly adapted to the tooth
Texture is similar to the outside of an orange—stippled
Color may differ according to the pigmentation of the person
40. Alveolar Mucosa
Thick and loosely
attached, covering the
alveolar bone
Flows into the tissue of
the cheeks and lips and
the inside floor of the
mandible
Immediately apical to the
mucogingival junction
43. Gingival Groove
Also called free gingival groove
The line of demarcation between the attached gingiva and
the marginal gingiva
44. Marginal Gingiva
Commonly called free
gingiva
Surrounds the teeth
Attached only at the
gingival groove
Appears light in color
(if healthy)
About 1mm wide
45. Interdental Gingiva
An extension of
unattached gingiva
between the
adjacent teeth
Also called the
interdental papilla
46. Gingival Sulcus
The space between the
unattached gingiva and
the tooth
In a healthy mouth, the
space would not exceed
2-3 mm in depth
47. Epithelial Attachment
The gingiva in the
floor of the gingival
sulcus that attaches
to the enamel
surface of the teeth
Also called
junctional
epithelium
48.
49. Black’s Classifications of Caries Lesions
Based on the location of the caries (cavities) on
the tooth
Developed by G.V. Black
“grand old man of dentistry”
Originally there were 5 groups, later class VI was
added
50. Class I
Cavities in the pit and
fissures of teeth
(A) Occlusal surfaces of the
posterior teeth
(B) Buccal or lingual pits on
the molars
(C) Lingual pit near the
cingulum of the maxillary
incisors
51. Class II
Caries on the proximal
(mesial or distal)
surfaces on the
posterior teeth
53. Class IV
On the interproximal
surface of anterior
teeth AND include
the incisal edge
54. Class V
Occur on the cervical third of the facial or lingual
surface of the tooth
Often occur because the patient regularly sucks on
sweets
55. Class VI
NOT part of the original
standard classification of
cavities by G.V. Black
Label cavities that involve
the incisal or occlusal
surface that has been
worn away due to
abrasion
