Fluoride, a naturally occurring mineral, plays a crucial role in dental health, yet its use and concentration have become a subject of recent controversy due to potential risks associated with overexposure. While widely advocated by health authorities for its benefits in preventing tooth decay, excessive levels can lead to various health issues, ranging from digestive distress to bone weakening.

One significant concern is fluoride poisoning, which can result from accidental ingestion of large amounts. Symptoms include nausea, vomiting, diarrhea, and abdominal pain. In rare, severe cases, it can affect heart rhythm and breathing, potentially leading to coma or death. However, lethal doses are exceptionally high, typically between 70-140 milligrams per kilogram of bodyweight, making such an outcome nearly impossible through typical exposure to tap water or toothpaste.

Another well-documented effect of excess fluoride, particularly in childhood, is dental fluorosis. This cosmetic issue develops when children are exposed to more fluoride than necessary during the formation of their adult teeth. It causes teeth to become discolored or brown and affects approximately 23% of the U.S. population. While primarily aesthetic, it underscores the importance of appropriate fluoride intake during formative years.

Beyond dental concerns, skeletal fluorosis can occur with chronic exposure to high fluoride levels, specifically over 1.5 parts per million—up to three times over safe limits. This condition weakens bones, leading to damage and joint problems, highlighting a more systemic risk associated with prolonged and substantial overexposure.

Despite these potential risks, there is broad scientific consensus that fluoride, as found in most tap water and toothpaste, is safe and beneficial for oral health. Leading health authorities and professional dental organizations worldwide strongly advocate for fluoride in water systems and dental products. Major proponents include the Centers for Disease Control and Prevention (CDC), which has recommended community fluoridation since 2001 and declared it one of the 20th century's greatest public health achievements. The American Dental Association (ADA) and the FDI World Dental Federation also endorse community fluoridation and its use in dental products. The World Health Organization (WHO) supports community fluoride initiatives, while prudently acknowledging the potential risks of overexposure.

The benefits of added fluoride are substantial, contributing significantly to individual and public health. Fluoride in toothpaste and water works by strengthening tooth enamel and effectively preventing tooth decay. For instance, in the U.S., where fluoride has been added to community water supplies since 1945, the CDC's Community Health Prevention Task Force found that it led to a 15% reduction in cavities. Furthermore, extensive research involving 96 studies concluded that users of fluoride toothpaste experienced fewer cavities on average, demonstrating its effectiveness in caries prevention.

Conversely, a lack of sufficient fluoride carries its own set of risks, primarily increasing susceptibility to tooth decay and cavities, which often necessitate dental intervention. Consequences can include significant tooth pain and sensitivity as enamel erodes and nerves are exposed. Untreated cavities can progress to form visible pits and holes, potentially leading to infections such like tooth abscesses—painful pockets of fluid around the tooth root. Ultimately, severe tooth decay can compromise the structural integrity of a tooth, making untreated cavities a leading cause of tooth loss.