Problem 18 - Objective Biology for NEET

Question

The dental formula of human is (a) \(\frac{0033}{3133}\) (b) \(\frac{1003}{1003}\) (c) \(\frac{2123}{2123}\) (d) \(\frac{3131}{3121}\)

Step-by-Step Solution

Answer

The correct dental formula for humans is (c) \(\frac{2123}{2123}\).

Step 1: Understand Dental Formula Structure

Dental formula shows the types and numbers of teeth in one half of the mouth. The digits represent - 'Incisors / Canines / Premolars / Molars'. Depicted is the upper jaw over the lower jaw. So a dental formula of \(\frac{2123}{2123}\) means that in one half of the mouth there are 2 incisors, 1 canine, 2 premolars, and 3 molars in both upper and lower jaws.

Step 2: Compare With Human Dental Structure

A typical adult human mouth has a dental structure of 2 incisors, 1 canine, 2 premolars, and 3 molars on each half of both the upper and lower jaws, so the dental formula becomes \(\frac{2123}{2123}\).

Step 3: Choose the Correct Option

After comparing the given options with the typical human dental structure, the correct option is (c) \(\frac{2123}{2123}\).

Key Concepts

Incisors

Incisors are the front teeth in your mouth. You have them at both the top and bottom. These teeth are generally the first ones you see when someone smiles. They play a crucial role in biting off pieces of food. Think of them as your mouth's natural scissors. In the human dental formula, you typically find two incisors on each side of your mouth, both in the upper and lower jaws.

Some interesting facts about incisors are:

• They have a flat edge for cutting food.
• Children have eight primary (baby) incisors, and adults have eight permanent incisors.
• Incisors are critical for pronunciation and aesthetics.

They are among the most visible and important parts of your dental anatomy. They're not just for show; they start the whole process of digestion by cutting your food down to a manageable size.

Canines

Canines are located next to your incisors, and they are easy to identify. They have a pointed shape designed for tearing food. With only one canine on each side in the upper and lower jaws, these teeth are typically sharper and longer than the others.

Here are some notable features of canines:

• They are also called "cuspids," named after their pointed cusp.
• Humans have a total of four canines, two in the upper jaw and two in the lower jaw.
• They help guide the movement of your teeth when you close your jaws.

While they might seem small in number, canines are essential for the proper movement and alignment of your teeth, contributing to a balanced bite.

Molars

Molars are the large, flat teeth at the back of the mouth. They play a major role in grinding food down, making it easier to swallow and digest. An adult human typically has twelve molars in total, with three on each side of the upper and lower jaws.

Let’s look at the features of molars:

• The first molars erupt around age six, which is why they are sometimes called "six-year molars."
• Third molars are known as "wisdom teeth" and usually appear later in your teen years or early twenties.
• They have broad surfaces with ridges designed to grind food thoroughly.

Molars are built to handle a lot of pressure and are crucial for effective chewing, which is the final step before you swallow your food.

Premolars

Premolars, also referred to as bicuspids, sit between your canines and molars. These teeth have two points or cusps and are designed for crushing and tearing food. Each side of your mouth typically has two premolars, meaning you have eight in total.

Some important aspects of premolars include:

• They are unique to adult dentition; children don't have premolars.
• Their position and structure help in breaking down food.
• They play a transitional role by transferring food from canines to molars.

Premolars support the primary functions of both canines and molars, making them versatile and critical for efficient chewing.