Tooth Anatomy: Structure, Elements, and Eruption

Posted on Mar 25, 2025 in Biology

Teeth: A functional element of the stomatognathic system. They are hard, small bodies formed by different tissues. Teeth are arranged in arches, joined by jawbone tissue.

Functions: Chewing, phonetics, swallowing, aesthetics, preservation of bone.

Architectural Elements of the Tooth (Crown)

  • Cusp: A pyramid-shaped structure with the base in the body of enamel. It is a peak in the chewing surface.
  • Cingulum: An enlargement in the cervical third of the lingual surface of anterior teeth.
  • Marginal Ridge: Convex enamel, longitudinal, appearing on the occlusal faces of molars and premolars, or the lingual surfaces of incisors and canines.
  • Mamelon: Corresponds to each of the 3 convexities found on the incisal edge of newly erupted incisors.
  • Supernumerary Tubercle: Applies to small cusps located on the crown, additional to a normal anatomical structure.
  • Crest: A defined and bulky relief, like a ridge but bigger.

Grooves and Fossae

Groove: A large depression on the surface of the posterior teeth. It corresponds to the action on the enamel surface and also occurs as a result of independent mineralization of each cusp.

  • Major or Developmental Groove: Very sharp and linear depressions formed during tooth development.
  • Secondary or Supplementary Groove: Small, more irregular furrows located on the occlusal marginal ridge.

Fossae: Irregular, deep excavations or holes located on the lingual surface of certain anterior teeth and the occlusal surfaces of posterior teeth.

  • Primary Fossae: Formed by the junction of two major grooves.
  • Secondary Fossae: Formed by the junction of a main groove with one or two secondary grooves. They are less extensive and shallower than the primary fossae.

Pits: Located at the depth of the fossae where two or more grooves meet.

Root Architectural Elements

  1. Apex: The terminal end of the root.
  2. Cervix: The part of the root closest to the cementoenamel junction (CEJ).
  3. Root Trunk: The portion of the root between the cervix and the point of root division.
  4. Furcation: The point of root division.
  5. Apical Foramen: A hole located in the apical third of the root, through which nerve endings and an artery enter the tooth.
  6. Root Canal: A large depression located on the proximal surfaces of the root.
  7. Dilaceration: Abnormal curvature of the root.

Tooth Eruption

We can distinguish 3 periods:

  1. Pre-eruptive Period: Predominantly bone destruction; the tooth begins to erupt along a nearly vertical trajectory, with a slight facial inclination.
  2. Eruptive Period: First, gingival destruction occurs, followed by the formation of the protective periodontium.
  3. Post-eruptive Period: Formation of the insertion periodontium.

There are 3 theories that attempt to explain why tooth eruption occurs. None of these theories have been scientifically proven.

  1. Mechanical Causes Theory: Root growth pushes the tooth outward.
  2. Vascular Effect Theory: New vessels are formed, increasing blood pressure, which pushes the tooth outward.
  3. Action of Periapical Tissues Theory: The formation of periapical tissues causes the tooth to erupt.