This can happen when children enjoy the taste of fluoridated toothpaste so much that they swallow it instead of spitting it out or when they brush more than prescribed or when they take too much of the product.
Fluorosis is basically a condition that affects your teeth caused by excessive exposure to fluoride during the first 8 years of life.
"Analysis of 2013-16 data found that over 38 per cent of children aged three to six years used more toothpaste than recommended by the CDC and other professional organisations", Xinhua news agency reported citing the report.
"Fluoride is a wonderful benefit but it needs to be used carefully", said Dr. Mary Hayes, a pediatric dentist in Chicago.
Fluoride is a mineral found in water and soil. Additionally, participants were not asked to specify whether the toothpaste had fluoride.
Nevertheless, the study revealed that when teeth are in the forming stage, excess fluoride can lead to dental fluorosis or tooth streaking or spottiness.
How was the experiment carried out? However, according to recent research by the Centers for Disease Control and Prevention (CDC), many children in the U.S. are doing it wrong.
In order to conduct the study, scientists from the Centers for Disease Control and Prevention included parents of over 5,000 children aged 3 to 15 years. According to the CDC, children aged 3 and under should only use "a smear the size of a rice grain", while kids between the ages of 3 and 6 should use no more than a pea-sized amount. Although fluoride has many benefits like preventing cavities, the CDC warns "ingestion of too much fluoride while teeth are developing can result in visibly detectable changes in enamel structure such as discoloration".
Of course, as parents of young children would readily understand, kids don't always do what you want them to - and tooth brushing is no exception. "We want the parents to be in charge of the toothpaste and toothbrush".
"The findings suggest that children and adolescents are engaging in appropriate daily preventive dental health practices", the authors write, "however, implementation of recommendations is not optimal". Nearly 40% of children between the ages of 3 and 6 are using toothpaste to excess, per the study.