dental science - unit 5

The Tooth: Functions, Tissues and Structural Landmarks

Name the various tooth surfaces, and where is it located?

• Incisal - The biting edge of an anterior tooth

• Palatal - The inner side of an upper jaw tooth that faces the palate

• Labial - The surface towards the lips

• Buccal - The surface towards the cheeks

• Lingual - The surface that faces the tongue

• Mesial - The surface that is closest to the midline of the face (side of tooth)

• Distal - The surface that is away from the midline of the face (side of tooth)

• Occlusal - The chewing surface of posterior teeth

• Proximal - Tooth surfaces that are next to each other

Name and identify the division of specific surfaces on a tooth.

For dividing a tooth surface into thirds:

• Mesial third

• Middle third

• Distal third

And horizontally:

• Cervical third – closest to the gum

• Middle third

• Incisal/occlusal third – closest to the biting/chewing edge.

Subgingival

• Apical - very tip of a tooth’s root

• Middle

• Cervical - closest to gums

Identify the parts of a tooth

• crown - top of tooth covered in enamel

• root - in the jaw covered in cementum

• cementoenamel junction - where enamel meets the cementum

• apex - at the terminal end of root(s)

• alveolar bone - where the tooth (root) is anchored

• bifurcation - where two roots meet

Describe the enamel tissue, their location within the tooth, their chemical composition, and their functions

Smooth cap covering and protecting underlying tissues of the tooth

• Most densely mineralized tissue of the body

  • composed of millions of tiny enamel rods to form framework of enamel

  • 96% inorganic (mineral) 4% organic matter and water

• Ameloblasts - cells that produce enamel

• Function: shields inner tissues from damage, decay, and temperature sensitivity

Describe the dentin tissue, their location within the tooth, their chemical composition, and their functions.

Directly underneath enamel of the crown and cementum of root

• Odontoblasts - cells that produce dentin

• Has dentinal tubules or odontoblastic tubules that run from outside surface of tooth to the pulp (inside)

• Function: structure support, pulp protection

Describe the cementum tissue, their location within the tooth, their chemical composition, and their functions.

covers the root and is like bone tissue - very thin layer

• 50% inorganic and 50% organic matter and water

• Cementoblasts - cells that produce cementum

• Function: anchors the tooth within the jawbone

Describe the pulp tissue, their location within the tooth, their chemical composition, and their functions.

located at the center of the tooth for entire length of tooth

• Soft and made up of blood vessels, cellular substances, and nerves

• Function: regenerate dentin and to provide nutrients to a tooth

• Pulp cavity - entire hollow space inside a tooth containing pulp (nerves and blood vessels)

What are the components of the pulp?

1. Pulp chamber - surrounded by dentin. Large, main central cavity located inside the visible crown of the tooth

2. Pulp horns - small, pointed extension of pulp chamber that stick upward toward chewing edges

3. Pulp canal - narrow channel that runs down through the root of the tooth

4. Apical foramen - small opening at the apex of the tooth. Channel for blood, lymph vessels and nerves to gain access to the interior area of tooth

Define the teeth landmark terminology: Lobe

A section of a developing tooth that helps form the crown.

Define the teeth landmark terminology: Developmental grooves

Small lines or grooves on a tooth that mark where two lobes meet.

Define the teeth landmark terminology: tubercle

a small elevated area of enamel on the lingual surface and sometimes the labial or occlusal surface

Define the teeth landmark terminology: fossa

wide, shallow depression on the lingual surfaces of anterior teeth

• Lingual fossae are found upon the lingual surface of incisors

• On canines, there are two lingual fossae

• Triangular fossae are found on molars and premolars on occlusal surfaces

Define the teeth landmark terminology: cingulum

a buldge of enamel found on the cervical third of the lingual surface of an anterior tooth

Define the teeth landmark terminology: pit

Small depressions or holes on a tooth, usually where grooves meet or cross.

Define the teeth landmark terminology: cusp

major elevation on the masticatory surfaces of canines and posterior teeth

Define the teeth landmark terminology: ridge

A raised line or edge on the surface of a tooth.

4 ridges on each cusp:

• Buccal/labial – toward the cheek/lip

• Lingual – toward the tongue

• Mesial – toward the middle of the mouth

• Distal – away from the middle of the mouth

Define the teeth landmark terminology: concavity

is a depression in a surface

Define the teeth landmark terminology: lingual groove

the developmental line or lingual groove that separates the 3 labial lobes from the cingulum (anterior tooth) or cusp(s) for a posterior toot

Define the teeth landmark terminology: triangular groove

Developmental groove that separates a marginal ridge from the triangular ridge of a cusp

Define the teeth landmark terminology: transverse groove

A groove that runs across the chewing surface of a tooth.