OROFACIAL W2 Teeth fx, Tongue, Salivary Glands

Crown and root of a tooth is joined at ?

CEJ - cementoenamel junction

Define Anatomical crown in comparison to Clincal crown

Anatomical crown is the whole crown of tooth that is covered by enamel regardless of whether it is erupted.

Clinical crown is the portion of the crown that is visible above gingiva

Division of root into 2 segments, 3 segments?

2 → bifurfaction

3 → trifurcation

The alveolus is also known as…

bony socket in which the tooth fits

What type of characteristics of the root offers more resistsance to displacement? Why?

long length and wide because more surface area for peridontal ligaments to attach to tooth.

Triangular shape + root lenght = high resistance to displacement

What are the 4 types of tooth tissue?

Enamel, Dentin, Cementum, Dental pulp

The hardest tissue in the human body is?

Enamel because its densely mineralized.

96% inorganic matter

What happens to our enamel as we age?

Enamel becomes thinner allowing dentin to shine through and teeth look darker.

Define dentin

Main portion of the tooth (body of tooth) composed of hard, dense, calcified tissue that is underneath enamel and cementum.

• Softer than enamel but harder than cementum and bone.

• Yellow in colour

• Has elasticity

70% inorganic matter

Which tooth tissue is capable of repairing itself?

Dentin

What is secondary dentin?

Type of dentin that grows very slowly and it initiated by normal wear down of dentin

What is reparative dentin?

The dentin that is laid down in response to caries or trauma

What is the main function of Cementum?

provide a medium for attachment of the tooth to the alveolar bone (by PDL)

45% inorganic, 55% organic

2 types: cellular (1/3) and acellular (2/3)

What makes up the dentinocemental junction (DCJ)?

union of cementum and dentin

What is the pulp of the tooth? What are its 2 divisions?

The pulp is housed in the center of the tooth and is surrounded by dentin.

• Composed of blood vessels, lymph vessels, connective tissue, nerve tissue, and ODONTOBLASTS (dentin forming cells)

Divisions:

1. Pulp chamber - coronal portion

2. Pulp canals - root portion

Pulp cavity = pulp chamber + canals

What is the chief function of odontoblasts?

Lay down primary, secondary, and reparative dentin

What kind of sensory information can be relayed from the nerves in the pulp?

Pain (not cold or heat, not pressure)

Which type of dentition is the longest?

Canines - best anchored because of its long root (maxillary canine has the longest root in the entire dentition)

How many cusps on a premolar?

2 or 3

How many cusps on a molar?

4 or 5

What characteristics act as landmarks on the crowns of teeth? (8)

1. Lobes (Facial and Lingual)

2. Lines aka developmental grooves formed when lobes fuse together

3. Tubercles - small elevations of enamel

4. Fossa - depression/concavity on a tooth

5. Cingulum - Lingual lobe of maxillar anterior teeth.

6. Pits - small pinplint holes in the enamel that occur along the lines or fossa

7. Cusps - mound on crown of tooth

8. Ridge - elevated portion of a tooth that runs in a line (on a cusp)

What are marginal ridges?

Rounded borders of enamel forming the mesial and distal shoulders of occlusal surfaces on posterior teeth and lingual surface of anterior teeth.

Compare and contrast the ridges on Posterior teeth

Triangular Ridge

• Main ridge on each cusp that run from tip of the cusp to central part of occlusal surface

Transverse Ridge

• Union of 2 triangular ridges, buccal and lingual, that CROSS the occlusal surface

The lingual groove of the anterior tooth separates…

4th lobe from labial lobes

The lingual fossa of the anterior tooth separates…

lingual lobe from the other 3 lobes

What are the 2 types of muscles of the tongue?

1. Intrinsic Muscle - within the tongue

2. Extrinsic Muscle - attached tongue to other structures

What type of epithelium is found on the tongue?

Stratified squamous epithelium

• Keratinized/Parakeratinized on the dosal surface)

What are the 4 types of papillae that are scattered on the dorsum of the tongue?

1. Circumvallate (Vallate)

2. Fungiform

3. Filiform

4. Foliate

Describe Vallate (Circumvallete) papillae

V-shaped row of circular dome-shaped elevations that divides the tongue into 1/3rd posterior and 2/3rd anterior portions.

• Consists of many taste buds

• Small salivary glands lie beneath vallate papillae called glands of Von Ebner

Describe Fungiform papillae

Tiny round, red, reaised, spots found on the anterior 2/3rds of the tongue.

• Taste buds are in these papillae

• only on the dorsal side of tongue

Describe Filiform papillae

Slender, threadlike, pointed projections on the anterior 2/3rds (middle-back) of the tongue that are responsible for TACTILE SENSATION.

• No taste buds

What is glossitis?

Glossitis is the inflammation of the tongue, characterized by swelling, redness, and changes in the tongue's surface texture (Very smooth)

• caused by vitamine deficiency

• “loss of epithelia” = smooth tongue surface

Describe Foliate papillae

reddish leaf-like folds of tissue found on the posterior 1/3rds of the tongue on the lateral sides.

• in humans, foliate papillae contain fewer taste buds and they are not very well developed.

What area does oral cancer begin?

Foliate papillae

The lingual tonsils are located …

just behind the circumvallate papillae at the base of the tongue.

What are the 3 pairs of salivary glands?

1. Parotid

2. Submandibular

3. Sublingual

Describe Parotid glands, its location and the secretions from this gland.

Parotid glands are grape-like clusters of cells that secretes into tubes leading to the oral cavity. Largest salivary gland of the 3.

Location:

• the surface of the masseter muscle, behind the ramus of the mandible.

Secretion:

• thin, watery serous fluid

• produces 25% of total resting salivary volume

Where do the parotid gland ducts open into the oral cavity?

maxillary 2nd molars. Aka Stenson’s ducts

Describe Submandibular salivary glands, its location and the secretions from this gland.

A mixed salivary gland that produces 60-65% of resting saliva. → aka. submaxillary gland

Location:

• below the body of the mandible and wraps around the mylohyoid muscle in the neck.

Secretions:

• Serous and mucous secretions (thicker and stickier)

Where to the ducts of the submandibular gland open into the oral cavity?

Sublingual caruncles at the base of the lingual frenum (ventral side of tongue)

Describe Sublingual salivary glands, its location and the secretions from this gland.

Smallest salivary gland of the 3 producing 10% of saliva. Consists of mostly mucous cells with a few serous cells.

Location:

• Anterior floor of the mouth next to mandibular canines

Secretion:

• Thickest secretions due to the mucous cells

Where do the ducts of the Sublingual gland open into the oral cavity?

Opens into the submandibular duct connecting to the sublingual fold (near canines)

• one major duct and several small ducts open in a line along the sublingual fold