Question

Which of the following terms describe human dentition?

A) Pleurodont, monophyodont, homodont

B) Thecodont, diphyodont, homodont

C) Pleurodont, diphyodont, heterodont

D) Thecodont, diphyodont, heterodont

Answer 1

Hint: The tooth comprises a crown, the part visible in the mouth, amongst all mammals, and one or more roots inserted in a gum socket. 

Complete answer:

Teeth are rigid, calcified frameworks that serve the primary purpose of chewing, lodged in the bone of vertebrate jaws. Humans and many other mammals have a transient collection of teeth; in humans, they usually emerge in between 6th and 24th months i.e. the deciduous, or milk, teeth. There are twenty in all: two lateral incisors, two middle incisors, two canines, and four premolars in each mouth. 

Now, let us find the solution from the options:

(A) Pleurodont is a type of tooth implantation widespread in all Squamata-order reptiles and at least one temnospondyl. A single collection of teeth is considered a monophyodont. As in the porpoises, Homodont is referred to as possessing all the teeth identical in front, as opposed to heterodont. Thus, option (A) is not the correct answer.

(B) A diphyodont would be any animal with two subsequent sets of teeth, the "deciduous" set initially and the "permanent" set sequentially. Homodont is referred to as possessing all the teeth identical in front, as opposed to heterodont. Thecodont is a dentition wherein the teeth in the sockets are lodged. 

Thus, option (B) is not the correct answer.

(C) Pleurodont is a type of tooth implantation widespread in all Squamata-order reptiles and at least one temnospondyl. A diphyodont would be any animal with two subsequent sets of teeth, the "deciduous" set initially and the "permanent" set sequentially. Heterodont is a dentition in which there are multiple types of teeth. Four types of teeth are accessible to humans, including incisors, premolars, canines, and molars. 

Thus, option C is not the correct answer.

(D) Heterodont is a dentition in which there are multiple types of teeth. Four types of teeth are accessible to humans, including incisors, premolars, canines, and molars. Thecodont is a dentition wherein the teeth in the sockets are lodged. Diphyodont is a dentition in which there are two partial and permanent sets of teeth. Both these are features of dentition in humans.

Thus, the correct answer is option (D) Thecodont, diphyodont, heterodont.

Note: In its bony socket, the section of the gum that covers the root, recognized as the periodontal membrane, cushions the tooth. The jawbone acts as a solid root anchor.