Facts about cavity-prone teeth

By Hong Kee-sang

Many parents are dismayed to learn during their children’s dental check-ups that they have dental decay. Sometimes better home care, preventive measures and regular monitoring are all that’s needed. Other times, however, extensive drilling and filling, capping, or even extraction of teeth is required, which is all the more problematic in young children as they are not yet capable of coping with such stressful situations on their own. They may need sedation or even general anesthesia, adding to the emotional and other burdens for the parents.

The question lots of parents ask, and dentists hear often, is “why?” Why are my kids’ teeth so prone to cavities? Do they have particularly weak, defective teeth? They have taken care, some of them even better than other parents, about what the kids eat, make certain they brush their teeth and so on. However, we know that there are some people who don’t seem to put in any effort into maintaining their oral health but get along fine without any decay or problems.

The casual, off-the-shelf answer you get is that you should brush your teeth and cut down on sugary snacks. Lots of parents make sure to abide by this advice — but their children still get cavities. Like anything in life, a simple answer usually doesn’t paint a full picture.

In dental textbooks, it’s taught that three things need to coincide for dental decay to occur — 1) teeth need to be present, 2) decay-causing germs need to inhabit the mouth and 3) the bacteria need to imbibe sugar to produce acid. Let’s take each, and additional factors, in turn.

Common sense, but teeth need to be present in the mouth for tooth decay to occur. An obvious point, to be sure, but a problem for babies who are born with a couple of teeth already in their mouths or babies who get their first teeth when they are very young and still actively bottle or breast feeding. Extra effort and measures need to be taken to prevent these natal and neonatal teeth, as they are called, from developing tooth decay.

A combination of fairly specific germs needs to be present in the children’s mouths for tooth decay to occur. When babies are born, their mouths are free of theses decay-causing bacteria — the germs infect the mouth after birth. And guess where the germs come from? DNA analysis of the germs and other research say usually from the parents or other caregivers in close contact with the child. And once the germs infect the mouths of your children, they are there for life. Good oral hygiene and preventive measures can reduce their number, but never actually eradicate the germs. Hence, it’s important for the parents to take care of their own oral health — get decay fixed in their own mouths and improve their own oral hygiene. The good news — if you can keep these germs from infecting the children’s mouth till they are four or five, the bacterial flora in their mouths will have stabilized. All the seats will have been taken up by other bacteria and the decay-causing germs won’t be able to get their feet in the door — a lifetime of little or no decay-causing bacteria. A number of prevention-oriented dental clinics provide simple tests (a la CSI-style swab test) to check for the presence and number of those germs.

The third element, sugar, is surprisingly non-specific. Sugar, as in cane sugar sucrose, is the most efficient and therefore preferred energy source for the decay-causing germs. The bacteria will use the sugar to produce acid that will dissolve minerals, weaken and break down the tooth (producing the cavity). The bad news — these germs are not very discriminating. They can use other sugars, called saccharides, from fruit or even milk. What to do then? It’s impossible to cut down completely on different sugars. This quandary leads to the next bit.

The fourth element, arching over all the three aforementioned factors, is time. Teeth, decay-causing germs and the different sugars need to be together for a sufficient amount of time for the disease process to occur. The rest of the time, varying from person to person, calcium, phosphate and other minerals are actually incorporated into the tooth surface — in effect helping the tooth to recuperate. Only when there is a negative balance between the outgoing and incoming does dental decay proceed. For this reason, cutting down the frequency of such foods, brushing soon after eating and drinking water often help rinse away food debris and syrupy starchy saliva following snacks help to prevent tooth decay.

Even the above outline of the disease process of tooth decay is an oversimplification. Other things such as oral pH and quantity/quality of saliva to name a few, affect the incidence and progress of dental decay in no small way. Those additional factors will be the subject of my next column.

The writer is a dentist at Seoul Children’s Dental Center in Cheongdam-dong, southern Seoul, and has General Registration as Dentist in Australia. For further questions, send an email to the writer at keesanghong@hotmail.com, or call the hospital at (02) 515-0926, or visit the hospital’s website, https://www.seoulchildrendentalcenter.com.