Fluorides play a significant role in the promotion of oral health, fostering remineralization, inhibiting demineralization processes in the enamel, and having antibacterial activity. 

There are two main types of fluoride: stannous fluoride and sodium fluoride. Both have benefits, but stannous fluoride may have a slight edge over sodium fluoride when it comes to fighting cavities.

What is stannous fluoride?

Stannous fluoride (SnF₂) is the more natural form of fluoride. It is derived from tin, which is found in small amounts in the earth’s crust. Stannous fluoride can actually inhibit the development of cavities. It also helps to remineralize teeth, which can reverse early signs of decay. It does this by adhering to the surface of tooth enamel. It then forms a protective layer which is able to shield enamel from the effects of erosive acids. Stannous fluoride is both bacteriostatic and bactericidal and can reduce bacterial growth and control biofilm. 

Stannous fluoride has an antimicrobial effect versus the bacteria which cause gum disease. It's important to note that any toothpaste will remove gum disease bacteria through just good brushing and flossing. A rinse like Listerine can provide a similar antimicrobial effect without the risk of staining.  The negative of stannous fluoride is that is can stain the teeth permanently.

Is stannous fluoride dangerous?

Since stannous fluoride is derived from tin, there is a potential to get tin toxicity in large amounts.

What is sodium fluoride?

Sodium fluoride (NaF), on the other hand, Sodium fluoride is a fluoride salt, and it is a synthetic form of fluoride. It is made in a laboratory by combining sodium and fluoride. Sodium fluoride is commonly used in dentifrices and oral rinses. Sodium fluoride is also effective at preventing tooth decay, but it is not as natural as stannous fluoride. Sodium fluoride is also not as active as stannous fluoride, but it is still helpful in preventing tooth decay. It works by strengthening tooth enamel, making it more resistant to plaque and acids.

Is sodium fluoride dangerous?

In its purest form, sodium fluoride is actually capable of eating through concrete. Although sodium fluoride was the first compound to be used within our country’s tap water system in 1945, it has since been changed to a different compound called fluorosilicic acid.

What is sodium monophosphate?

Sodium monofluorophosphate (Na₂PFO₃ or SMFP) is similar in efficacy to sodium fluoride and can be considered equivalent.

Unlike sodium fluoride, Sodium Monophosphate is not an ionic fluoride salt, but rather a covalently bound compound that requires enzymatic activation by a salivary enzyme (alkaline phosphatase) to release bioavailable fluoride. Because of this lower reactivity, SMFP is compatible with more abrasives than other fluoride sources.

There are other fluorides like amine fluoride 297 (C₂₇H₆₀F₂N₂O₃)

Is sodium monophosphate safe?

The usual content of SMFP in toothpaste is 0.76%. The compound is used in place of sodium fluoride, particularly in children's toothpastes, because it is less acutely toxic, although both have modest toxicities. 

According to a study in 1993, sodium fluoride (NaF) was more effective in cavity prevention over sodium monofluorophosphate. Note- this study did not include amine fluoride.

There are some important distinctions between stannous fluoride and sodium fluoride. For one, stannous fluoride is less likely to cause dental fluorosis. Dental fluorosis is a condition that can cause discoloration and pitting of the teeth. It is a rare side effect, but it is more likely to occur when using sodium fluoride.

Another distinction is that stannous fluoride is more beneficial for combating early tooth decay. It can help to stop tooth decay before it becomes a problem. Sodium fluoride is not as effective at this task.

A study was published in the Journal of Nutrition that stannous fluoride was superior to the sodium fluoride in preventing caries, when the fluoride was added to food and in drinking water. However, this compound appeared to be no more toxic than sodium fluoride in high concentrations.

Both stannous fluoride and sodium fluoride are available in toothpaste and mouthwash. They can also be prescribed by a dentist in the form of a fluoride gel or solution.