Title: What exactly is a cavity?

Illustration of a tooth with a cavity

Cavities are an infection caused by bacteria that find their way into teeth.  Eventually they get through the enamel (the outer white part of the tooth).  I liken this to a shield.  It is the strongest stuff in the body, much harder than bone.  Even so, bacteria infect the enamel and then enter the next deeper layer of the tooth called dentin.  Dentin is yellow and surrounds the pulp and nerve deep inside the tooth.

Sugar is eaten by the bacteria who convert it to acid which is then excreted on or inside your tooth giving them room to borough to be protected from your mouth. (Think about that the next time you suck on a hard sugar candy for an hour)  Your mouth is a very dangerous place for bacteria.  Your saliva itself and fluoride kills them.  Over the millennia these simple single-celled creatures have developed the ability to protect themselves in this way by hiding inside the tooth and developing resistance to the acid that they make which actually kills competing bacteria of other strains.

Using refined simple sugars from sugarcane, we pass these specific decay-producing bacteria on from parent to child.  How do we stop this?  If you are a parent or going to be a parent, get your cavities taken care of before infecting your children.  This sounds harsh but it is 100% accurate.  Next take your family to the dentist twice a year starting at about 12 months of age.  Eradicate cavity producing bacteria from the mouths of all family members and you will keep from passing these bacteria on from generation to generation.  But we have a powerful weapon…

Fluoride is so useful because it lowers the pH levels necessary for bacteria to achieve with the acid they produce to dissolve tooth structure, making your shield stronger as the tooth is growing during childhood.  This is why we fluoridate water, not to make you a communist…The best concentrations seem to be about 1 PPM (part per million) to 0.6 PPM in drinking water.  Too much and white or brown spots form on the developing permanent teeth; too little and cavity rates increase.  Once formed fluoride does not cause spots on the teeth.  This is why we pack fluoride into ADULT toothpaste.  This is also why you want to give young children under seven years old children’s toothpaste which does not contain as much fluoride.  Kids tend to swallow adult toothpaste leading to toxic levels causing spots on the forming teeth.

After the eruption of teeth, fluoride is just as useful by microscopically patching up the holes punched by bacteria and even killing bacteria at the surface of the teeth.

Saliva kills bacteria too, but more importantly it is itself an acid buffer.  Saliva has the ability to keep bacteria-produced acid from achieving a pH strong enough to dissolve tooth structure.  There is a finite ability for your saliva to do this.  That is why snaking in-between meals is so bad.  It takes time for your saliva to “re-charge” its buffering capacity.

All sugars are not created equally.  Simple sugars like high sucrose corn syrup are easily metabolized by bacteria. Complex starchy sugars are not.  Frequent snakes with sticky sugars that hang in your mouth for hours or beverages like fruit juice, sugar soda pop and coffee are great food sources for cavity producing bacteria.

Are all bacteria bad? Why not kill them all with mouthwashes that are high in alcohol?  The truth is that very few strains of bacteria lead to infection.  It is a diet that selectively gives advantages to the few cavity-producing strains that is the problem.  A balanced diet with whole fruits and vegetables limits cavities.  Processed simple refined sugars should be limited to meal times only.

Infants and toddlers are another age-group in trouble across the country.  Baby bottle tooth decay is on the rise.  Giving babies milk, juice, or anything other than plain water is a common cause for many early childhood cavities.  Limiting your baby to active-feeding defined meal times stops this.  Introducing complex sugars in natural foods also helps.  JUICE is not healthy for teeth!  Neither are gummy candy vitamins.  Finally, all children need supervised brushing every day, even babies with just two teeth!

BOTTOM LINE: cavities are 100% preventable with adequate but not excessive fluoride, good care at home, routine visits to your dental office, and with a healthy diet.

Dr. Philip Estes