By Lakshmi Hariharan

It was always a treat to see the dining table filled with goodies. The after-school games with friends had made Rithik and his brother Ranbir extremely hungry.

Of course, any eight- and twelve-year-old boys like them would be. They went to the same school and eagerly looked forward to their daily games with friends in the apartment complex. Every evening, they played until sunset and returned home happily tired. After finishing their homework and studies, they knew a healthy, sumptuous dinner awaited them.

But today was even more special. Their mother had kept their favourite ice cream for dessert.

Gulping down another scoop of chocolate ice cream, Rithik smiled happily at his mother. Life was good, he thought—at least until his father reminded him to brush his teeth before going to bed.

Oh no! That was something he did not like… and neither did Ranbir.

Voicing his displeasure, he said, “But Dad, we already brushed in the morning, and we surely will tomorrow morning too. Isn’t that fine?”

“Well, boys, come here and sit down,” their father said calmly. “Now tell me, do you like sweets and chocolates?”

“Of course!” they shouted in glee.

“Hmmm… Your teeth have bacteria, and they too love sugary stuff. They sit happily around your teeth, feeding on the chocolate and ice cream you have had. Later, they produce acid, which makes a hole in your tooth. This hole is called a cavity.”

The boys listened carefully.

“There are four layers in every tooth,” their father continued. “Enamel, the hard outer layer. Dentin, the middle layer. Cementum, which covers the root. And the pulp layer, where all the blood vessels and nerves are. The bacteria dig deeper and deeper, trying to reach the pulp. When they do, it causes pain, which we call a toothache. But this can be prevented by brushing your teeth.”

He explained further, “During the day, saliva, talking, and eating help push bacteria away. When we rinse our mouth with water, the bacteria are washed out. But during the night, when we sleep, everything is quiet inside the mouth. The bacteria can dig happily without disturbance. That is why brushing before going to sleep is very important. It prevents cavities from forming and reaching the pulp, which causes pain and inflammation. Do you want that?”

“Never!” the boys chorused immediately.

Their father smiled. “Do you know what is in toothpaste? There are five main ingredients.”

He began counting on his fingers.

“First, fluoride. All toothpastes have fluoride to strengthen teeth and prevent cavities. Sodium fluoride acts like a shield.

Second, glycerol or glycerine. This prevents the paste from drying out and helps it glide smoothly from the tube.

Third, sorbitol. Like glycerol, it holds the paste together and makes it sweeter and tastier—but bacteria do not like it.

Fourth, calcium carbonate. This helps remove stains and plaque from the surface of teeth. Along with brushing, it keeps teeth clean. Some toothpastes use silica gel instead.

Fifth, sodium lauryl sulphate. A very small quantity produces the bubbly foam, like in soap or shampoo.

And finally, water, which helps dissolve and mix all the ingredients.”

Ranbir’s eyes widened. “Dad, I always wondered why the paste never dries up inside the tube.”

Their father chuckled.

Even before the conversation ended, the two boys were already heading towards the washroom. They had made a firm promise—to never skip brushing their teeth before bedtime again.

From the doorway, their mother reminded them gently, “And don’t forget to use your new toothbrushes. They must be replaced every two or three months.”

The boys nodded, smiling at each other, as they squeezed the paste onto their brushes.

That night, they brushed carefully, knowing the small ribbon of paste was their shield against invisible enemies—and the secret to keeping their happy smiles safe.