Dental Decay (Dental Cavity, Dental Caries)

To know how to prevent dental decay, we need to know how it forms

Dental decay based on studies by Fitzgerald and Keyes (1960) is an infectious and transmittable micro-biologic disease of the tooth that results in localized dissolution and destruction of the calcified tissues (enamel).  It is the most prevalent condition affecting over 2 billions people worldwide.

There are many different types of bacteria in our mouths, but only some that are known to associate with cavities.  The most common bacteria include Streptococcus Mutans, Lactobacillus Casei and Acidophilus, and Actinomyces Naeslundii.

Other environmental factors that influence cavitation in the enamel are:
  • Acidic condition in the saliva can erode (demineralize) the enamel (the outermost layer of the tooth), results in a cavity

  • Routinely consume diets rich in sugars and starchy foods.  The by-product aAfter bacteria digest simple carbohydrates (sugars, starchy foods) is acid.  Prolong exposure to these foods results in larger cavities and more teeth involvement.
Recent year, researchers found that dental decay has more complex factors than previously described by FItzgerald and Keyes. And they also found that dental decay is a non-infectious disease with site-specific, preventable and reversible.  The new concept involves the balance between 2 factors:
  1. Risk factors: include acid producing microorganism, diets rich in carbohydrates, the change of the status of the saliva (composition, flow rate, ph), dental plaque (biofilms)
  2. Protective factors: include fluoride exposure, the flow rate and ph of the saliva, and good oral hygiene
Dental caries develops when risk factors overwhelm the protective factors for a long period of time or with high frequency .  Other elements that play important role in the development of dental caries are genetics, immune system, lifestyle, age, socio-economic status, and an anatomy of the tooth.

The process of dental tooth caries

First stage;
In general, tooth structure oscillates between demineralization - loss of minerals (calcium phosphate) at low pH and remineralization - gain minerals at the more neutral or high pH.

Researchers found the dental plaque at the tooth surface was a primary cause of lower pH in the oral cavity. During demineralization, the surface color and texture of enamel may change to brown. As long as the enamel remains intact, remineralization can occur, allowing calcium and phosphate to return to enamel matrix substructure.  At this stage, no filling is necessary.  Observation in this area is indicated to see if the dental cavity proceeds to the second phase.

Second stage;
Dental caries becomes deep, extensive breakdown of the enamel occurs, exposing a dentin (second layer of tooth structure).  At this point, remineralization is not possible, a filling is necessary. In some cases, any stimuli such as heat, cold and tactile sensation may trigger sensitivity to mild pain. The dentin itself has no nerve or blood vascular system, but the sensation travels through the exposed dental tubules in the dentin to the nerve in dental pulp chamber at the center of the tooth.

Third stage;
Dental caries penetrates deeper inside the tooth, exposing the nerve fibers, arteries, veins and lymphatic vessels in the pulp chamber.  Patients may experience severe pain. Root canal treatment is a treatment of choice.  Without any treatment, the tooth breaks down; infection begins at the root tip causing bone destruction and intensified pain.

The development of dental cavity

How to stop the decay
According to the California Dental Association Journal published in January 2016, the use of Silver Diamine Fluoride (SDF) has been found to arrest and prevent dental caries.  What makes SDF effective against decay is the silver component kills the bacteria and stop the decay, while fluoride hardens what is left through remineralization.  SDF has been approved by the U.S. Food and Drug Administration in 2014 for tooth hypersensitivity but dentists around the world had been used SDF off label to arrest decay with high success in an active, non-symptomatic carious lesion for decades. Consult with your dentist if SDF can be applied to your cavity.  The final restoration of the decayed tooth is still necessary to restore the full function of the tooth.  The CDT code for dental insurance claim is 1354: Interim caries arresting medication application.

Here are some suggestions for preventing dental caries:

1. Diets:
Be selective in your diets. Eat whole foods, vegetables, and fruits.  Avoid sour candies, carbohydrate-containing foods that can feed bacteria made it readily adhere to tooth surface, e.g.,
  • White rice
  • Bread and pasta made from white flour 
  • Most packaged cereals
  • Highly processed, sugar-containing foods such as candy, cake, corn syrup
  • Fruit juice
  • Soft drink.  
2. Proper flossing before brushing your tooth.  Flossing removes dental plaque and food remnants between the teeth, prevents cavities at the contact between the teeth

3. Proper brushing technique: Improve your oral hygiene; learn how to brush your teeth properly and maintain regular cleaning after eating by flossing and brushing.  Ask your hygienist to demonstrate the proper way to clean your teeth if you are unsure of your method.  Include water irrigation such as Waterpik Ultra Water Flosser into your cleaning routine.  Learn how to use water irrigation from here.

4. Type of Toothbrush: Select a toothbrush with soft and rounded bristles. Change toothbrush every few months.

5. Type of toothpaste: Use the toothpaste that contains xylitol or fluoride.

6. Visit your dentist every six months for examination and cleaning even if you don't think you have any problem.  The dentist can find a hidden problem and prevent it from developing into a big problem.

7. Avoid chewing on ice, bone or another hard object as they can chip and crack your teeth and let the food trap in the rough areas.

8. The benefit of using XylitolA study from the Department of Operative Dentistry from the University of Florida shown; chewing xylitol-sweetened gum three times a day, reduce caries risk in preschool children.  Xylitol suppresses Streptococcus mutans, the chief pathogen responsible for dental caries. Another study from Department of Dental Public Health Sciences at University of Washington is also supporting the anti-cariogenic properties of xylitol.

 How to floss properly:
There are two types of dental floss: waxed and non-waxed.
  • The non-waxed dental floss uses in a not too tight contact between two teeth
  • The waxed dental floss uses in a close contact or the contact that includes filling on the side of the tooth

Steps of proper flossing:

Cut 18 inches of floss; wind most of the floss around left middle finger

Wind the rest of dental floss around the right middle finger 

Hold dental floss with thumbs and forefingers with 1 inch apart between 2 thumbs

Insert floss between teeth with gentle saw motion

Wrapping the floss around the tooth, allow the floss to go below a gum line

Scrape the floss up and down the tooth
Advance floss after each cleaning by unwind the floss in one finger and wind the floss on the other. Continue flossing the side of all teeth.

Recent years, dental floss holders have been developed to accommodate those who want to floss while away from home.  Floss holders are available in different shapes and sizes; some are disposable, and some are refillable. Floss holders may add the convenient to flossing away from home, but the efficiency of plaque removal are less than hand-held method.

To floss the tooth with bridges, braces, implants or close contacts; use Threader Floss, which is designed to slide easily under the bridges or close contacts.

How to brush correctly:

Select a toothbrush with soft-bristled the size that fit your mouth and brush with gentle strokes.  Brush your teeth after each meal.

Front and back outer surfaces - Place brush 45 degrees angle to the gums;
move the brush sideways gently in short strokes, rotate toward chewing surfaces

Inside front teeth - place tip of the brush at the gums then rotate up toward biting surfaces

Inside back teeth - Place brush 45 degrees angle to the gums;
move the brush sideways gently in short strokes then rotate toward chewing surfaces

Chewing surfaces - Place brush on top of chewing surfaces and scrub back and forth

Microbiology of Dental Plaque by Dr. Susan Kinder Haake
American Dental Association