Oral Cavity Anatomy

Oral Cavity Components

• The oral cavity comprises lips, gingiva, cheeks, tongue, floor of mouth, palate (both soft and hard), and teeth.

Lips

• Lips consist of an upper and lower lip, connected by commissures.
• Philtrum is a vertical groove located on the upper lip.

Gingiva

• Gingiva is soft tissue covering tooth roots.
• The components of gingiva are free and attached gingiva. They are separated by a free gingival groove.
• The gingiva between teeth is called the interdental papilla and is free gingiva.

Cheeks

• Cheeks, or buccae in Latin, refers to the face area below the eyes, between the nose, and the left or right ear.
• "Buccal" refers to anything related to the cheek.
• The vestibule or buccal pouch/cavity is the area between the inside of the cheek, teeth, and gums.

Tongue

• The tongue consists of muscle fibers and glands.
• The tongue is important for speaking, taste, mixing food, swallowing, and teeth cleaning.

Macro-Anatomy of Tongue

• Anterior two thirds is the papillary part.
• Posterior one third is the lymphatic part.
• The tongue is separated by the sulcus terminalis.

Floor of Mouth & Palate

• The area beneath the tongue has salivary glands and blood vessels.
• The mouth's roof consists of a hard and soft palate.
• The hard palate consists of an incisive papilla between the upper central incisors, is the anterior part, and has rugae area (anteriorly) with a median palatine raphe.
• The soft palate is the posterior part, redder than the hard palate.
• The uvula is a small soft structure hanging from the center of soft palate's posterior part.

Teeth

• Teeth arrange in the upper and lower arches or jaws.
• The upper arch teeth are called maxillary teeth, fixed in the maxilla.
• The lower arch/teeth are called mandibular teeth. They attach to the mandible (movable jaw).
• The mandible joins to the skull by the TMJ (temporomandibular joint).
• The midline is an imaginary vertical line that divides the dental arch into two equal halves.
• The horizontal line that upper teeth occlude with lower teeth is the occlusal plane.

Dividing Each Dental Arch

• Each dental arch can be divided into two halves.
• There are four quadrants: the upper right maxillary, lower right mandibular, upper left maxillary, and lower left mandibular quadrants.

Teeth Function

• Teeth are used for mastication (chewing).
• Incisors are for cutting food.
• Canines have a wedge shape for tearing food.
• Premolars and molars are for grinding food.
• Teeth affect appearance and speech.
• The jaw is affected: if a child eats on one side, jaw growth will be unilateral

Teeth Types

• Incisors
• Canines
• Premolars
• Molars

Incisors

• There are two front teeth in each quadrant in the mouth.
• The central incisor is the first tooth next to the midline and the lateral incisor is second.

Canine (Cuspid)

• The canine is the cornerstone and is the third tooth from the midline.
• There is one canine in each quadrant.

Premolars

• Two premolars are in each quadrant.
• They are the fourth and fifth teeth from the midline.

Molars

• There are 3 molars in each quadrant.
• They are the sixth, seventh and eighth teeth from the midline.

Types of Dentition

• Primary dentition occurs from 6 months to 6 years.
• Mixed dentition happens from 6 to 12 years.
• Permanent dentition occurs from 12 years onward.

Primary Dentition

• The Deciduous dentition is also known as milky teeth or predecessors. It occurs from 6 months to 6 years.
• Around six months is when this period begins with the eruption of the lower first deciduous incisor, the upper second deciduous molar erupts last at about 24 months.
• All deciduous teeth typically reach the occlusal plane at 3 years old.
• There are 20 primary teeth. 2 incisors, 1 canine, 2 molars are in each quadrant.

Mixed Dentition

• Two types of teeth, deciduous and permanent, are present.
• The permanent molar erupts first at six years old.
• By 12 years old, the last deciduous tooth upper canine sheds.
• Shedding means the physiological loss of deciduous teeth.
• The ugly duckling stage is the space of shedded teeth and the gingiva experiences redness and swelling. Also, there is the presence of teeth that are of different sizes because some are deciduous while some are permanent

Permanent Dentition

• Permanent dentition is also called secondary or adult teeth or successors teeth.
• It begins at 12 years old and is complete over the life.
• There are 32 teeth.
• Each quadrant has 2 incisors, 1 canine, 2 premolars, and 3 molars.
• Permanent premolars succeed deciduous molars. Permanent molars have no predecessors.

Dental Formula

• It is used to differentiate between human teeth and teeth of other species.
• It indicates the dentition of one side of mouth only.
• There are 16 human permanent teeth for one side, upper and lower.
• There are 10 human deciduous teeth for one side, upper and lower.

Human Dental Formula

• Human dental formula of permanent teeth: I 2/2 C 1/1 P 2/2 M 3/3
• Human dental formula of deciduous teeth: I 2/2 C 1/1 M 2/2