As a practicing dentist for over 33 years, many patients have walked into my office with different concerns. The two main problems we see as dentists, are cavities (dental caries) and periodontal disease.
Since the 1950’s, when most community tap water and toothpastes were first fluoridated, we have seen a huge drop in the number of dental cavities. However, decay is still a problem for some people even though the water is fluoridated, and even if we apply fluoride toothpastes and mouth rinses on a routine basis. Some people develop frequent cavities, some never do, and some decay infrequently or can limit decay by integrating consistent dental therapy into their lives.
“Soft Teeth” or “A Tooth for Every Baby”?
What separates these 3 main groups of people: those who never get cavities, those who get some cavities, and those who are very prone to dental decay? Some people still come into my office with the following rationale for their decay: “I have soft teeth”, or “since I became pregnant, the baby removed the calcium from my teeth.” We were taught as dental students that dental caries, or cavities, were caused by a single bacteria contained in the plaque and saliva, Strep Mutans. Scientific research and modern dental practice have combined to identify the true causes of tooth decay and to provide modern methods to help prevent it.
Effect of Filling Material on cavity development
I have noticed that cavity-prone individuals don’t do well with composite fillings, which are the current tooth-colored type of filling we use. Decay seems to begin and lodge between the junction of the filling and the tooth- what we call recurrent decay. Amalgam, or metal-based, restorations seem to be more resistant to this bacterial invasion. An older type of filling called silicates, which are no longer in use, never seemed to allow recurrent decay (alongside or underneath). Whenever I remove one of these older restorations due to wear or discoloration, some of which have been in place for over 50 years, I have never seen any decay under or around this type of filling. Silicate fillings released fluoride, and did so over a long period of time, negating the effect of high acids in the area. This type of filling is not used today because they tend to be weak, to stain and discolor, and do not withstand heavy forces. But the fact that they have resisted the influence of decay over long periods of time is quite a remarkable observation.
Why does a cavity start?
The reason any disease can start and flourish is because of the environment. Most of life is based on equilibrium, or what is known as homeostasis. When the environment is ripe for a change to occur that is detrimental to the body and the body cannot fight back, there is a change in the equilibrium. However, any disease process in which the body tends to fall out of proper health and function has a chance to return to a normal state. Changing the environment for the better can return the body back into homeostasis and normal function and health.
The outer shell of the tooth is composed of enamel. The enamel in all our mouths is constantly subjected to being destroyed by acids (de-mineralized) and rebuilding ( re-mineralized). Forces that destroy the enamel tend to be low pH mouth environments (acidic conditions), and forces that repair and rebuild the teeth tend to be neutral or even basic (higher pH). Recent changes in therapy are based on returning the pH and biofilm back to homeostasis. It’s almost like “training your bacteria.” Other factors are listed below.
Factors affecting the tendency to develop cavities
- pH and type of saliva
- The amount and type of microbes present on or near tooth surfaces
- The condition of the enamel of the teeth – a rough enamel surface makes it easier for bacteria to attach
- Saliva flow
- Current and past medical conditions
- Thorough and consistent oral hygiene
- Presence of oral appliances such as braces or dentures
Dental Plaque – Biofilm
What used to be called dental plaque is now referred to as biofilm. Biofilm is a tenacious collection of saliva, partially broken down food, and pathogens (bacteria). It is this community of organisms and sticky environmental film, when attached to the tooth, that can cause tooth decay. Every person has biofilm.
Biofilm itself is not the problem. Not all biofilm is the same. The difference between the amount, type, and PH of the biofilm from one individual to another is what differentiates each person’s proneness to decay.
In unhealthy, prone mouths, the bacteria seem to live in a high acid environment, and also produce very high acids. Healthy mouths, on the other hand, have “healthy” types of bacteria that don’t produce or live within communities of high acidity. The more acidic the biofilm type, the greater the breakdown of tooth enamel can occur. You can think of the cavity creation process as if if the mortar, which solidly locks bricks together, is dissolved, or de-mineralized, and the bricks begin to fall apart. Dental decay (or cavities as they are known) starts out as a localized de-mineralization due to the acid environment that first appears as a chalky white spot. As the decay matures, it changes color and texture. The once-hard tooth enamel is now soft and pliable and can be scraped or broken off easier, subjecting the areas adjacent and underneath to continuous and more rapid decay as the decay spreads.
Whereas Strep Mutans used to be described as the only culprit, now over 40 other different bacteria are known to accelerate the dental decay process. Decay progresses slowly in the enamel due to it’s highly calcified, inorganic nature. But the second layer of the tooth, called dentin, is softer, organic, and less calcified. The decay can quickly spread right through this layer of the tooth and then reach the nerve of the tooth, called the pulp. Pain happens when bacteria-caused decay nears the nerve of the tooth. This does not happen until well into the decay process as the disease spreads and perforates through the enamel and into the internal layers of the tooth. When the nerve is attacked there is then the need for root canal, due to infection.
Saliva Protects & Rebuilds Teeth
Saliva is a major protective element of the mouth and teeth. Not only does it have antibacterial activity, it can also dilute and neutralize acid formation in the mouth. Components of saliva continually bathe and re-mineralize tooth enamel. Reduced saliva flow, usually due to medications or medical issues such as Sjogrens Syndrome, can reduce the defenses to fight off tooth decay or the effects of acid-producing food and drink to which tooth enamel is subjected.
Early Detection & Prevention of Cavities a Good Investment
Since it is the acidity and amount of the biofilm that determines the cavity process, we must recognize people who are at risk and identify their risk category and then make informed recommendations for an effective strategy of treatment. Early detection of decay is important to preserve tooth integrity, to protect the vulnerable dentin, to avoid pain, and to avoid the expense of dental fillings or even root canal. Prevention is now a better investment than ever with the addition of professional evaluation combined with effective modern treatments to avoid cavities.
Professional Evaluation of Risk of Cavities
Recent developments in dentistry allow object evaluation to assess how prone a person is to dental caries. The objective assessment of risk allows us to make suggestions for types of therapy and treatment to help our patients avoid future dental cavities and maintain a healthy mouth.
This is best done in early childhood to allow prompt intervention to decrease or prevent cavities. Many parents aren’t aware that cavities are preventable, and therefore don’t have their children assessed or have intervention done early enough to prevent disease. We see many 3-7 year old children with multiple cavities who don’t regularly see a dentist or who never have gone to a dentist. The bulk of this disease could have been prevented had the parent brought the child in at an early age so that minimal treatment (if any) would need to be performed to maintain a healthy mouth with many fewer cavities.
Many adults are at risk, as well, and suffer unnecessary cavities that could be avoided or sharply reduced using modern techniques. Unfortunately, like young children, many adults do not get regular preventive check-ups to ensure maintenance of healthy teeth.
The professional cavity-risk evaluation process includes:
- How many existing cavities are present
- How many fillings are already present
- How much plaque is left on the teeth
- pH acidity of plaque (neutral or acidic), measured most effectively by an optional pH meter test.
- Evaluation of other risk factors, such as saliva, medical conditions and diet
- Assignment of risk category and identification of main cause of cavities
Evaluation made by a dental professional using these risk factors is called CAMBRA (Caries Management By Risk Assessment). A person with elevated risk factors is not destined to suffer tooth decay, but they are more at risk of getting decay and must be more aware and attentive to factors they can control, such as regular checkups, consistent dental hygiene and treatment, and good diet.
Modern Tools Reduce Risk of Cavities
There is no magic pill or solution to cure dental caries. There are, however, products currently on the market that enhance re-mineralization of the enamel, decrease the effect of acid biofilm and improve the pH level of biofilm on the enamel surface.
- Fluoride, either a lower-strength over-the-counter or higher-strength by prescription, creates a re-mineralization of enamel and actually incorporates itself in the outer bands of enamel making the enamel shell less prone to breakdown. Examples include ACT Anticavity Flouride Rinse and Prevident 5000 Plus. In certain individuals, providing a carrying medium, known as a fluoride tray, helps concentrate and flush the fluoride into the needed areas.
- Xylitol is actually a sugar contained in many chewing gums and candies. The bad biofilm bacteria seem unable to process this type of sugar, and it can also reduce the amount and the tenacity of the acid-producing bacteria to shift the flora to the good type of biofilm. This product also induces the flow of saliva which, in itself, is protective as well as contributing to re-mineralization. Examples include Trident chewing gum and Xyloburst gum and mints.
- A high-pH anti-bacterial rinse containing small amounts of sodium hypochlorite. The effect of the sodium hypochlorite is to cut through the heavily organized acid producing biofilm and destroy the bacteria. The destruction of the organized biofilm and neutralization of the low PH environment can provide stability to the mouth. An example would be CariFree Treatment Rinse.
- Chlorhexidine mouthrinses burst the membrane of the bacterial cell wall, reducing the amount of bad bacteria. Examples include Peridex and Periguard (both have .12% chlorhexidine gluconate).
Preventing Cavities: Cost-effective, Healthy, Preserves Smiles
In summary, cavity formation is caused by multiple factors. For people who may be more susceptible to cavities due to one or more factors, brushing and flossing may not be enough to prevent the formation of cavities. A professional dental assessment categorizes the risk for each person, taking into account predisposing conditions, utilizes a thorough dental examination, dental x-rays, and an evaluation of dental plaque. Based on this objective risk assessment, therapy using modern over-the-counter or prescription medications can help cavity-prone people avoid the pain and expense of fillings and root canal treatments and help them maintain healthy beautiful smiles, returning their mouths into proper homeostasis.