Dental Anatomy Study Notes

Ch 2- FUNCTION OF TEETH

  • Essential functions:

    • Protecting the oral cavity

    • Acquiring and chewing food

    • Aiding the digestive system in food breakdown

  • Physical barrier:

    • Teeth protect oral structures; serve as weapons

    • Example: Carnivora mammals (e.g., lions and tigers) have developed canines used for defense and hunting

  • Communication role of teeth:

    • Necessary for speech, phonetics, and whistling

    • In many cultures, dental appearance influences sexual attraction

TOOTH STRUCTURE

  • Each tooth consists of two main parts:

    • Crown:

    • Covered by enamel

    • Root:

    • Covered by cementum

  • Junction between crown and root:

    • Cementoenamel junction (CEJ) is where cementum meets enamel

    • The cervical line marks this junction

ERUPTION AND TYPES OF CROWN

  • After eruption, the crown is never covered by gum tissue again

  • Clinical vs. Anatomic Crown:

    • Anatomic Crown: Entire crown covered by enamel, regardless of eruption

    • Clinical Crown: Portion visible above the gingiva

  • Eruption process:

    • Involves moving through surrounding tissues

    • Can exhibit single, bifurcated, or trifurcated roots

    • Roots held in jaw by alveolar process (supports teeth) and fit into alveolus (bony socket)

TOOTH TISSUES

  • Four primary tissues of teeth:

    • Enamel:

    • Outer surface of the crown

    • Thickest at crown tip, thins at cervical line

    • Color varies with thickness and mineralization

    • Contains 96% inorganic material and 4% organic matter/water

    • Most mineralized and hardest tissue in the body

    • Wear-resistant, allows self-cleaning ability due to smoothness

    • Dentin:

    • Main body/component of the tooth

    • Chemical composition: 70% inorganic and 30% organic matter

    • Capable of self-repair (secondary dentin)

    • Cementum:

    • Covers the root; not perfect layer, some dentin exposed

    • Composed of 45%-50% inorganic and 50%-55% organic components

    • Two types: cellular and acellular cementum

    • Dental Pulp:

    • Nourishing and sensory center of the tooth

    • Contains blood vessels, lymph, connective tissue, nerve tissue, and odontoblasts

TYPES OF TEETH

  • Incisors:

    • Designed for cutting; incisal edge for biting

    • Shovel-shaped lingual surface helps guide food

  • Canines:

    • Function as holding/grasping teeth

    • Long roots provide stability and lateral stress support

  • Premolars:

    • Between canines and molars; not as long as canines

    • Usually have two or more cusps to aid in grinding food

  • Molars:

    • Larger teeth with four or more cusps for chewing/grinding food

    • Not designed for incising; interlock with upper/lower teeth

SURFACES OF TEETH

  • Anterior teeth:

    • Four surfaces:

    • Lingual: Facing the tongue

    • Facial: Facing cheek/lip (Labial for anterior; Buccal for posterior)

    • Proximal: Two surfaces:

      • Mesial: Closest to midline

      • Distal: Away from midline

    • Incisal ridge: Edge of anterior teeth

  • Posterior teeth:

    • Five surfaces:

    • Lingual, Facial, Proximal (Mesial, Distal), and Occlusal

DIVISION, LINE ANGLES, AND POINT ANGLES

  • Surfaces can be divided into thirds for facilitation of locating areas

  • Line Angles: Junction where two surfaces meet

    • For example, the junction of buccal and occlusal surfaces is termed buccoocclusal

  • Point Angles: Junction where three surfaces converge

    • Example: mesiolabioincisal where mesial, labial, and incisal surfaces join

LANDMARKS

  • Teeth develop from lobes; fusion marks are visible as developmental grooves

    • Incisors and canines have three facial lobes and one lingual lobe

    • Molars have four to five lobes, differing by type

  • Fossae: Depressions/indentations named for their locations

    • Pits: Small pinpoint holes along developmental grooves or fossae

    • Cusps: Major mounds on tooth surfaces, absent on incisors

RIDGES AND CONCAVITIES

  • Ridges: Elevated portions running in line across the tooth

  • Concavity: Carved-out areas, opposite of convexity

REVIEW QUESTIONS

  • A series of questions designed to test comprehension of tooth structure, function, terminology, and anatomical considerations regarding teeth, their surfaces, and their tissues.