While fluoride is generally considered safe and beneficial at appropriate levels, excessive exposure to fluoride can have potential negative effects. It's important to maintain a balance and avoid both inadequate and excessive levels of fluoride intake.

Here are some potential cons or risks associated with fluoride:

1. Dental fluorosis: Excessive fluoride intake during tooth development can lead to dental fluorosis, which is a cosmetic condition that affects the appearance of tooth enamel. Mild fluorosis appears as white specks or streaks on the teeth, while severe cases may cause brown discoloration and pitting.

2. Skeletal fluorosis: Prolonged exposure to high levels of fluoride can result in skeletal fluorosis, a condition that affects the bones and joints. Symptoms may include joint pain, stiffness, and limited mobility. However, skeletal fluorosis is typically associated with long-term exposure to very high levels of fluoride found in certain regions with naturally occurring high-fluoride water sources.

3. Neurological effects: Some studies have suggested a possible link between high fluoride exposure and adverse neurological effects, particularly in children. However, the evidence is not conclusive, and more research is needed to fully understand any potential risks.

The recommended optimal level of fluoride in drinking water varies depending on factors such as climate, access to other sources of fluoride (e.g., toothpaste), and age groups targeted for protection. In most countries where water fluoridation is practiced, the target range for optimal fluoridation is typically around 0.7-1.2 parts per million (ppm). This range aims to provide dental benefits while minimizing the risk of dental fluorosis.

It's worth noting that regulatory agencies carefully monitor and regulate fluoride levels in public water supplies to ensure they remain within safe limits.

If you have specific concerns about fluoride consumption or need personalized advice regarding your individual circumstances, I recommend consulting with a healthcare professional or dentist who can provide you with accurate information based on your situation.