How do cavities form?
Tooth decay is a disease process where a tooth's calcified tissues are damaged by the acidic waste products produced by bacteria that live in dental plaque.
Cavity formation is not a straight-line process. Instead it's the end result of a constant battle between two opposing processes, tooth demineralization and remineralization, where demineralization has won out.
1) Tooth demineralization
Demineralization is a process that damages teeth. When it occurs, mineral content is dissolved from calcified tooth tissues (enamel and dentin) due to the presence of an acidic environment.
As it progresses over weeks and months, a transition takes place from just some minor surface changes to the development of internal damage too. Ultimately, a point can be reached where a tooth's structural integrity has been so compromised that an outright hole (a "cavity") has formed.
Conditions needed for demineralization.
Before tooth demineralization can occur, the following conditions must exist (at minimum).
- A location on a tooth where dental plaque is allowed to accumulate, and remain in place for prolonged periods of time.
- The presence of certain types of bacteria in this plaque that create acidic waste products (referred to as "cariogenic" bacteria).
- A sugary food supply for these bacteria, especially sucrose (table sugar).
How all of this works.
a) The bacteria get a meal.
When we eat sugary foods (or types of foods that can be broken down into sugars), the cariogenic bacteria in our mouth get a meal too. When they digest these sugars, they produce acid waste byproducts that build up in the dental plaque that surrounds them.
b) An acidic environment is created.
As more and more sugar is digested by the bacteria, the acidity of the dental plaque increases. If it reaches a point where its pH is around 5.5 or lower, conditions are acidic enough that mineral content can be dissolved from the tooth's calcified tissues.
Over time, the amount of damage cause by repeated cycles of this action can cause substantial tooth damage, to the point where a hole has formed.
2) Tooth remineralization
Remineralization is a healing process that attempts to keep the progress of cavity formation in check. It can be considered to be tooth demineralization in reverse.
Whereas demineralization occurs at dental plaque pH levels of 5.5 and below, remineralization has a chance of taking place when less acidic conditions exist. When it occurs, minerals taken from a person's oral environment (from foods and saliva) are incorporated back into areas where demineralization has previously occurred.
Xylitol can help to promote remineralization.
The two processes, demineralization and remineralization, are in constant competition with each other. Throughout each day, cycles of demineralization and remineralization will take place. Ultimately, whichever one predominates over the long term decides what type of decay rate a person will experience.
Individuals who don't brush and floss effectively, and constantly snack on sugary foods and beverages, will tend to tip the scales in favor of the demineralization process. And as a result, they will likely experience a high decay rate.
People whose habits and efforts interfere with the elements needed for tooth decay formation will typically have an oral environment that's relatively less acidic (one that allows remineralization to be the dominant process). Thus offering them the protection and corresponding low decay rate that remineralization offers.
As you read through the pages of this site, you'll discover that xylitol's role in preventing tooth decay is really quite straightforward. Xylitol use helps to prevent those conditions that must exist before tooth demineralization can occur. Additionally, it may also have a role that facilitates the remineralization process.