Question

What is Dentition? What ar the types of the teeth? What are the parts of a tooth? Explain briefly.

Answer 1

Dentition:

• Two sets of teeth make their appearance at different periods of life of a man.
• The first set, known as the deciduous or milk teeth, is temporary and begins to erupt during the first and second years.
• The other set called the permanent teeth, begins to replace the first set from about the sixth year.
• The deciduous set consists of 20 teeth of which 4 incisors, 2 canines and 4 molars are found in each of the upper and lower jaw.
• The permanent teeth are 32 in number.
• The dental formula represents the arrangement of teeth in each half of the upper and the lower jaw.
• The entire formula is multiplied by two to represent the total number of teeth.
• The dental formula for milk teeth in humans is: Each half of the upper jaw and the lower jaw has 2 incisors, 1 canine, and 2 molars.

(a) The crown: The projected portion beyond the gum.

(b) The root: The portion that lies embedded in the sockets of the maxilla or mandible.

(c) The neck: The constricted portion between the root and the crown.

• The different types of the teeth are:

Incisors:

• They form the front teeth in each dental arch.
• The crown is chisel shaped.
• An incisor bears only one root.

Canine:

• The crown is large and conical.
• The root is usually single.

Premolars:

• The crown presents two pyramidal cusps or tubercles, one lingual and the other labial, the two being separated by a groove.
• The root is usually single.

Molars:

• Upper molars-the crown of the first, second and third molars present 4, either 3 or 4 and 3 cusps respectively.
• Each molar has 3 roots.

Lower Molars:

• The first molar presents 5 cusps while the second and third have either 4 or 5 cusps.
• Each lower molar possesses 3 roots.

Dentition:

The arrangement of teeth in the upper and lower jaws, i.e., mainly on the premaxilla, maxilla and dentary bones is called dentition