Question

Dental formula of adolescent human being before seventeen year
A. $\dfrac{{2122}}{{2122}}$
B. $\dfrac{{2123}}{{2123}}$
C. $\dfrac{{2102}}{{2102}}$
D. $\dfrac{{2023}}{{1023}}$

Answer 1

Hint: Alphabet and numbers are used to designate the type and number of teeth present in the dentition in a dental formula. The same method is also used to describe the dental formula of all different species such as sheep, horse, cat, and dog; other than humans. Dental formula for a normal adult is $\dfrac{{2123}}{{2123}}$, but for an adolescent human being before seventeen years, the last molar teeth in each jaw which are called as wisdom tooth are not present.

Complete answer:
The way of expressing or describing the total number of teeth in a man or an animal according to their dental arrangement is termed as the Dental Formula. Here, the formula is expressed using letters and figures. Letters used are based on the four types of teeth: Incisor, Canine, Premolar, and Molar.
The Dental Formula can be expressed as: \[\dfrac{{Number{\text{ }}of{\text{ }}each{\text{ }}type{\text{ }}of{\text{ }}teeth{\text{ }}in{\text{ }}upper{\text{ }}jaw}}{{Number{\text{ }}of{\text{ }}teeth{\text{ }}on{\text{ }}one{\text{ }}side{\text{ }}of{\text{ }}the{\text{ }}lower{\text{ }}jaw}}\]
In an adult human, permanent dentition consists of 32 teeth in total, by which the dental formula is $\dfrac{{2123}}{{2123}}$which indicates two incisors, one canine, two premolars, and three molars in each quadrant. But for an adolescent human being before seventeen years, the last molar teeth in each jaw are usually called wisdom teeth and are not present.

Hence the dental formula will be $\dfrac{{2122}}{{2122}}$.

Note:
During childhood, the deciduous dentition gets shed and is replaced by permanent dentition. The shedding and eruption of deciduous dentition is vital for the correct growth and space allocation for permanent dentition. There are variations in dental formula between species and can be different for the maxillary and mandibular dentition. For example, the dental formula of a dog is $\dfrac{{3142}}{{3143}}$, which indicates that there is an additional molar in the mandible.