Introduction/
Structure of Oral Cavity
Dr.Hina Nasim
Assistant Professor
Oral Biology
Learning objectives
At the end of this session students will be able
to:
• Define dental terminologies
• Identify different landmarks inside the oral cavity
• Identify the hard and soft tissues inside the oral cavity
Definition of Oral Biology
• Oral biology deals with the origin, growth,
development, structure, and functions of the
oral cavity.
• It overlaps basic dental sciences and clinical
dental sciences
Basic terminologies
Anatomical terminology
Directional terms
Term Meaning
Superior Above (or toward the
head)
Inferior Below(or toward the
feet)
Proximal Closer to the
trunk/origin
Distal Farther from the
trunk/origin
Medial Toward the midline
Lateral Toward the side
Anterior Toward the front
Posterior Toward the back
Anatomical terminology
Dental terms
Term Meaning
Facial/labial/buccal Toward the face /lips/cheek
Lingual Toward the tongue
Palatal Toward the palate
Buccal Toward the cheek
Maxillary Related to maxilla
Mandibular Related to mandible
Cervix/cervical The neck of tooth
Apex Tip of root
Mesial The surface of tooth closet to midline
Distal The surface of tooth away from midline
Occlusal /Incisal Chewing surface of teeth
Dental terminologies
Dental terminologies
Cervix
apex
Oral Cavity
• The oral cavity extends from the lips and
cheeks externally to the pillars of the fauces
internally, where it continues into the
oropharynx.
Lips
Pillars of
fauces
Cheeks
Divisions of the oral cavity
Oral cavity
Jaw and
alveolar Oral cavity
Vestibule proper
process, teeth
Divisions of the oral cavity
Oral
cavity
proper
Vestibule
Jaws,
alveolar
process &
teeth
Boundaries of the oral cavity
• Anteriorly : Lips
• Posteriorly: Faucial arches
• Laterally: Cheeks
• Superiorly : Palate
• Inferiorly: Muscular floor mainly tongue
Lips
Palate
Cheeks
Faucial
arches
Floor of the
mouth
Tissues of the oral cavity
Oral
tissues
Soft tissues Hard tissues
Tongue ,
Bone of jaws &
Oral mucosa,
Hard palate,
Salivary glands
Teeth
Soft palate
Landmarks in the oral cavity
Oral vestibules
Oral Vestibules
• The horseshoe-shaped spaces/slit like space
in oral cavity b/w lips and cheeks, and the
teeth and alveolus.
o Maxillary vestibule
o Mandibular vestibule
Oral vestibules
Buccal fat pad
Oral vestibules
Parotid
papilla
Oral vestibules
• The vestibular fornices form the superior and
inferior margins of the oral vestibule, where
the mucosa of the cheeks and lips reflect back
onto the alveolar mucosa.
Oral vestibules
• Labial/buccal frenum are sickle shaped fold of
mucosal tissues between labial/buccal mucosa
and alveolar mucosa.
Clinical Considerations
• Fordyce’s spots:
“Small yellowish elevations on the labial or
buccal mucosa represents the deep deposits of
sebum from sebaceous glands.”
• Linea alba:
“White ridge of raised callused tissue seen on
the buccal mucosa at the level where maxillary
and mandibular teeth occlude”
Fordyce’s granules
Linea alba
Jaws, Alveolar processes & Teeth
Jaws, Alveolar processes & Teeth
• Jaws
– Present deep to lips within oral cavity.
Jaws
Upper jaw Lower jaw
(maxilla) (mandible)
-Two maxillary
-Single bone
bones
- moveable
-fixed
Jaws
Maxillary bone
Mandible bone
Jaws, Alveolar processes & Teeth
• Alveolar processes
– Bony extensions of maxilla and mandible that
contain sockets(alveolus) of the tooth.
– The mucosa covering the alveolar processes is
known as alveolar mucosa
Maxillary
tuberosity
Alveolar processes
Jaws, Alveolar processes & Teeth
• Teeth
– Hard calcified structures found in the jaws of
vertebrates serving for prehension and
mastication of food.
– Constitute approximately 20% surface area of
mouth.
– Consist of a crown and root part.
Parts of a tooth
Structure of tooth
Tooth Supporting structures
Cementum
Enamel
PDL
Dentin
Alveolar bone
Pulp
Gingiva
Structure of tooth
• Enamel
“ It is the outermost hard,
inert, acellular tissue of the
tooth crown, derived from
the epithelial cells
(ameloblasts)”
– Highly mineralized(96%
inorganic material)
– Brittle
– Avascular
Structure of tooth
• Dentin
“It is a mineralized, elastic,
yellowish-white, avascular tissue
enclosing the central pulp
chamber”
– Derived from odontoblasts
– Mineralized (75% inorganic
component)
– Forms bulk of tooth
– Sensitive
– Capable of repair & regeneration
Structure of tooth
• Pulp
“It is a loose connective tissue
enclosed by the dentin.”
– It is the only soft tissue of
tooth.
– It is contained within the
pulp chamber and root canals
of the tooth
– Contains nerves and blood
vessels.
Structure of tooth
Supporting structure of tooth
• Cementum
“It is a bone like outer most
covering of the tooth root and
is interlocked firmly with the
dentin of the root”
– Hard similar to bone(45-50%
inorganic component)
– Derived from cementoblasts
– Avascular
Supporting structure of tooth
• Periodontal ligament
“The PDL is a highly
specialized fibrous connective
tissue situated between the
tooth and the alveolar bone”
– Principal function is to
connect tooth with alveolus
– Contains sensory receptors
– Provides nourishment to
avascular cementum
Supporting structure of tooth
• Gingiva
“The pale pink oral mucosa covering the alveolar bone
and the necks (cervical region) of the teeth is known as
gingiva/gums”. Further subdivided as:
1. Free gingiva(lies unattached around the cervical region of
the tooth)
2. Attached gingiva(firmly attached to the bone around teeth)
– A scallop-shaped line is present between attached
gingiva and alveolar mucosa known as mucogingival
junction
Clinical Considerations
• Torus
“ Tori are benign localized overgrowths of bone
found in both the upper (torus palatinus) and
lower (torus mandibularis) jaws.
Oral cavity proper
Oral cavity proper
• The inside of mouth is known as oral cavity
proper.
• It’s a space enclosed anteriorly by maxillary &
mandibular arch and posteriorly it opens into
the pharynx via faucial isthmus.
Oral cavity proper
• Palate
“ It is the roof of the mouth, separates the oral
cavity from nasal cavity.”
– It has two parts:
• Hard palate(firm anterior part)
• Soft palate(looser posterior part)
– A midline ridge of tissue on the hard palate is
known as median palatine raphe
Oral cavity proper
– A small bulge of soft tissue present just behind
maxillary incisors is known as incisive papilla.
– Firm irregular ridges of tissue radiate from the
present just behind incisive papilla are known as
palatine rugae.
– A midline muscular structure hangs down from
soft palate is known as uvula.
Palate
A=palatoglossal fold
A=incisive papilla B=palatopharyngeal fold
B=midlian palatal raphe C= palatine tonsils
C= palatal rugae D= uvula
D= alveolus
Oral cavity proper
Tongue
“The tongue is a muscular organ with its base attached to the floor
of the mouth”
• It has three :
Post 1/3rd
– Root
– Body
Ant 2/3rd
– Tip
• It has 3 surfaces:
– Ventral
– Dorsal
– Lateral
Oral cavity proper
• Ventral surface of tongue
– Covered by non-keratinized mucosa
– Large blood vessels (deep lingual vein).
– Lateral to lingual vein is a fimbriated fold known as
plica fimbriata.
Ventral surface of tongue
Oral cavity proper
• Dorsal surface of tongue
– The dorsal surface of tongue has a midline
depression (median lingual sulcus).
– It also contains numerous projections known as
(lingual papillae).
• Filiform (thread-like)
• Fungiform (mushroom-shaped)
• Foliate (vertical ridges)
• Circumvallate (walled-around)
A=circumvallate papillae
Lingual papillae Foliate papillae
B=lingual tonsils
Fungiform papillae
Filiform papillae
– An inverted V-shaped groove separates the root and
body of tongue (sulcus terminalis).
– A pit like depression present at the apex of sulcus
terminalis known as foraman cecum.
– Posterior to the sulcus terminalis, an irregular mass
of tonsillar tissue , the lingual tonsil are present.
median lingual
sulcus
Oral cavity proper
Floor of the mouth:
– It is present inferior to the ventral surface of the
tongue.
– A fold of mucus membrane connects the ventral
surface of the tongue to the floor of the mouth
(lingual frenum).
– A fold resembling a fringe on the undersurface of
the tongue on either side of the frenulum
A= lingual frenulum
B= plica fimbriata
C=lingual vein
Oral cavity proper
• A V-shaped ridge of tissue present in the floor
of the mouth known as sublingual fold. It
contains the opening of sublingual duct.
• A small papilla present on the anterior end of
sublingual fold known as sublingual caruncle.
It contains the openings of submandibular and
sublingual lands.
Salivary glands
• Three paired major
salivary glands:
a) Parotid glands
b) Submandibular glands
c) Sublingual glands
d) Multiple minor salivary
glands throughout oral
cavity
• Produces mixed saliva -
complex fluid
composition varying by
gland
• Primary environment for
teeth in oral cavity
Functions of Saliva
Physiological Functions Protective Functions
• Contains digestive
• Moistens oral cavity
enzyme amylase
• Dilutes harmful
• Facilitates speech
substances
• Lubricates food • Cleanses mouth
• Aids in taste perception
• Contains antibodies and
(solvent for food
antimicrobial agents
molecules)
• Maintains oral pH
through buffering capacity
References
• Berkovitz, B. K., Holland, G. R. & Moxham, B. J. 2017. Oral Anatomy,
Histology and Embryology E-Book, Elsevier Health Sciences.
• Ten cate's oral histology: development, structure, and function.
THANK YOU!
