Overview of Cavities
What follows is for information purposes only. Your individual circumstances are unique and may vary from the text below.
Written by Ronald Birnbaum DDS December 2007
Human teeth start their development at a very young age. The quality of the development of the tooth - and its ultimate performance and longevity - can be influenced by events that occurred during your childhood, particularly at that period in time the tooth was being created. By the time the tooth has erupted into the mouth, a different set of factors take over that can influence the longevity of the tooth.
Teeth start from scratch as groups of cells that grow at specific points in the jaw. These cells can have their performance disrupted by certain events that take place while they are busy at work.
One of the most common factors that disrupt the cells are medications- usually antibiotics, that you were given as a child at particular points in time. Other common factors are vitamin deficiency or excess, sickness and trauma. Even the mineral composition of the water you were fed has a strong influence on the teeth at all times, teeth need sufficient- but not too much- calcium and fluoride circulating in your blood so they may form with correct strength. Therefore whether you grew up drinking reservoir water, ground well water or premium bottled spring water makes a huge difference in how your teeth are today.
Problems arising from developmental events may be seen in your teeth today as: weakened or malformed enamel, discolorations in the tooth (any color), growth in unusual directions and an increased susceptibility to attack by the bacteria that cause tooth decay.
Cavities are formed by certain bacteria that make a home in and around the teeth. Bacteria that are known to cause tooth decay feed off the food you put in your mouth and love sugar. Even if you maintain a low-sugar diet, certain foods high in carbohydrates will provide enough nourishment to the bacteria. Therefore keep your mouth as clean as possible by brushing twice a day and using dental floss daily, in order to minimize the food source available to the bacteria. These bacteria also prefer an acidic environment, therefore even sugar-free soda, containing "citric acid" is not good for you.
The use of a fluoride rinse may also help because fluoride can "stun" some bacteria and simultaneously deposit minerals on the surface of the teeth to make the tooth more resistant to attack. Once a tooth has grown into the mouth, only good oral hygiene, the use of a fluoride rinse and a proper diet can mitigate the factors that cause cavities.
Unfortunately, in today's high-stress lifestyle of fast food, sugar-packed coffees available on every corner and caustic diet-sodas, our teeth are under as much attack as ever before. We are even seeing an increase in the amount of tooth decay, a disturbing reverse in gains made over the past 30 years.
By reading this article, I hope you will become more educated about the main points of tooth decay.
Cavities
1. Pit and fissure type of cavity
All teeth start their lifetime carrying naturally developed grooves, fissures and "pits" that occur in humans with regularity and in well mapped locations on the surface of teeth. If the formation of these sites has been successful and of good quality, those areas are naturally sealed and can be highly resistant to decay. However, in many people, these grooves, fissures and pits, especially where they are most numerous- on the back teeth, can have areas deficient by their formation. These sites present as naturally-formed cracks where food can enter from the moment the tooth is born. These holes are only microns wide and virtually invisible.
Due to the narrowness of the opening, your toothbrush bristle is usually too wide to reach inside the hole to clean. Over months and years, the bacteria in the mouth can find a home in these holes and live comfortably, well fed by the food you provide them. The byproducts of these bacteria are acidic and cause a breakdown of the adjacent enamel, starting a "cavity" and proceeding to create a bigger hole than what was originally there. A well developed tooth can present some resistance to the attack, but any area that suffered during tooth development is going to be less resistant and the cavity will progress faster.
These "pit and fissure" cavities represent the most common type of cavities. Most people will have at least some susceptible areas. A high sugar diet feeds the bacteria more, drastically speeding the development of a cavity, and once again, your toothbrush bristle cannot reach inside to clean while all this is going on. In most respects, there is nothing you can do to prevent the decay from occurring, other than (1). maintain a diet low in sugar to slow bacterial activity, (2). maintain overall good oral hygiene to minimize bacterial colonization, (3). use of a fluoride rinse and (4). hope your teeth are well formed and resistant enough to attack.
Pit and fissure cavities are most often found by poking the surface of the tooth with a pointed instrument to detect the presence of a hole. If the instrument finds a hole, it will get "stuck" to a certain extent. Usually there will also be some discoloration around the opening, a clue to its presence, but this is not always the case. This makes the detection of these cavities relatively easy, but also a hit-and-miss experience, as one cannot judge the extent of the decay merely by the outside appearance. Sometimes a large and dangerous cavity is present but its surface appearance is innocuous or even undetectable and the patient (and dentist) unaware of any problem until it is too late.
Once a hole is detected it must be cleaned out of its bacteria to put a stop to the decay and the hole filled to restore strength to the tooth. If the bacteria have progressed deeply, the nerve of the tooth may have been affected by the bacteria as well, requiring additional cleaning of the infected nerve called a "root canal". Luckily, this occurs only in the deepest of cavities, and usually there will have been warning signs, such as a sensitivity to extreme temperatures or to sweet foods, so that the patient can tell the dentist long beforehand that something is afoot. From the earliest start of a cavity to needing a root canal usually takes two to three years of progression at minimum in most people.
Most pit and fissure cavities are found and treated in persons between the age of 20 - 30 since these types of cavities are present or susceptible to development immediately after the tooth has erupted into the mouth and gain speed during active teenage or college years, especially where the person has diets higher in sugar and not taken ideal care of themselves. However, these cavities will still occur at any age and as the teeth wear down or chip, newly susceptible areas will present themselves.
The placement of a "coating" over susceptible areas immediately upon tooth eruption, can successfully seal the opening of pits and fissures, thereby keeping bacteria out, but it needs to be placed as early as possible before sufficient bacterial colonization occurs. Most insurance companies recognize this and will willingly support paying for sealants, but not beyond the age of 16, as by then a colonization has been established.
Luckily, in 2008, treatment for most pit and fissure cavities has become markedly easier and more cost-effective as recent developments in dental materials have greatly simplified the procedures involved and eliminated the need for the unsightly "metal" fillings. We can now use tooth colored filling materials almost exclusively and with great success in safety and reliability, often without the need for any injection except in the case of the deepest of cavities.
2. Interproximal (in-between teeth) type of cavity
This type occurs in-between teeth on the smoothened surfaces. No pit or fissure needs to be present so their development is not dependent on the pre-existing anatomy of the tooth.
Because of their location, most of the time they cannot be seen except with a radiograph (x-ray). When the dentist views the radiograph, the in-between areas of the teeth become visible and the cavity can be detected by looking at places known to be susceptible.
These cavities occur mainly if food has been allowed to get stuck between the teeth or if sugar has been carried in-between the teeth frequently. Therefore, a low-sugar diet goes a long way to reducing their formation, but most important is to keep the in-between areas clean with dental floss on a daily basis. Flossing is extremely important in their prevention. The use of a fluoride rinse also helps by strengthening tooth enamel.
These cavities are about as common as the pit and fissure type. However, unlike the former, the interproximal cavity is more preventable. So if your oral hygiene habits are good, chances are you can slow or prevent the progression of these cavities. However, they are more difficult to detect since we have to depend on the quality of the diagnostic equipment to show them, so by the time they become visible, they have usually attained a certain size that requires immediate attention.
If allowed to progress, the tooth will break down quickly and the nerve can become painful, requiring a "root canal".
Treatment for interproximal cavities in 2008 can be done with tooth colored filling materials yet salmost always requires the use of an injection to numb the tooth.
3. Other types of cavities
Fillings are rarely going to last for a lifetime. As you go through life, you will wear down your teeth and your fillings will wear also. Even a well done filling can chip and get decay at any roughened edges once a bacterial trap occurs, requiring the removal of the filling and the cleaning out of any recurrent decay. Sometimes, decay around a filling starts at some hard to find corner and goes dangerously unnoticed as it buries underneath the filling. At some point the filling, once it has lost its footing - can "fall out" or worse- the decay makes a path straight for the nerve, necessitating a "root canal", yet all looks fine and dandy from the surface- except maybe for a tiny opening at the edge of the filling that allowed bacteria to enter. Any sensitivity to temperature or sweet, or food getting trapped around a filling are clues leading to its discovery. Any filling where breakdown at its edge is suspected needs to be considered for removal and inspection.
Gum recession, areas damaged by trauma, certain health problems and other factors unique to an individual can also lead to tooth decay. The information is above is only generalized and explains the cavities that occur in most people, most commonly.
Post-script
By the way, did I mention genetics? No, that is because it is not a likely factor for tooth decay. If you say your grandma's teeth are bad and your mom's teeth are bad, therefore yours are going to be bad, although it could be due to factors other than tooth decay, it could best be summarized as "a family that eats candy together loses its teeth together". Genetics you are born with, but bad habits that live within families often lead to similar health issues amongst its members. So please take care of yourself better than your parents and grandparents did, that will go a long way to breaking the spell.