Question

Human dentition is described as
A. Heterodont, diphyodont, and thecodont
B. Heterodont, monophyodont, and thecodont
C. Heterodont, diphyodont, thecodont, and bunodont
D. Heterodont, polyphyodont, and pleurodont

Answer 1

Hint: Dentition is the number, kinds, arrangement, and structures of teeth. The teeth are the pointed structures present in the gums in the mouth. They help in cutting, biting, chewing, and masticating the food.

Complete answer: Different types of teeth:
1. Types of teeth based on their occurrence in the lifetime:
a) Monophyodont – These teeth appear once in a lifetime. The twelve teeth of humans are monophyodont.
b) Diphyodont – These teeth appear twice in a lifetime. The twenty teeth of humans are diphyodont.
c) Polyphyodont – These teeth appear several times in a lifetime. Polyphyodont teeth are present in the frog, snakes, maxillary teeth, etc.
2. Types of teeth based on their origin:
a) Acrodont – These teeth originate directly from the jaw. Acrodont teeth are present in amphibians, lizards, snakes, etc.
b) Pleurodont – These teeth are attached to the bony socket. Pleurodont teeth are the fangs of snakes.
c) Thecodont – These teeth are embedded in the bony sockets. Thecodont teeth are present in mammals, crocodiles, etc.
3. Types of teeth based on their function:
a) Homodont – These teeth are all similar in function and resemble closely to each other.
b) Heterodont – These teeth are all dissimilar in function and they vary in their structures. Heterodont teeth are present in humans. The different types of teeth present in humans are Incisors, Canines, Premolars, and Molars.
4. Types of teeth based on their shape:
a) Selenodont – These teeth are crescentic in shape. Selenodont teeth are present in horses, elephants, etc.
b) Bunodont – These teeth have cusps. Bunodont teeth are the Premolar and molar teeth in humans.
c) Secodont – These teeth are pointed and sharp. Secodont teeth are present in Lion, Tiger, etc.
d) Lophodont – These teeth have a transverse ridge in them.
Therefore, human teeth can be categorized as monophyodont, diphyodont, thecodont, heterodont, and bunodont.
Hence, the correct answer is option C.

Note: A tooth is made up of two different kinds of layers. These layers are the enamel and the dentine. The enamel is the hardest layer of the body. It is ectodermal, white, and made up of neuroblast cells. The dentine is the main layer and it is yellow in colour. It is soft and mesodermal in origin. The dentine is made up of odontoblast cells.