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Dentist in Edmond, OK | My tooth doesn’t hurt, why do I need a filling?

By October 1, 2011September 27th, 2022No Comments

Patients often ask me why they need a filling if their tooth doesn’t hurt. Also, for every patient that actually asks, I know there are probably five thinking the same thing in their head that don’t bother to mention it. When someone does ask, I often tell them that maintaining teeth is similar to maintaining a car engine. If you waited until your car engine showed symptoms (i.e. seized up) to change the oil, it would be a lot more time consuming and expensive to fix than if you took preventative action and actually performed routine maintenance. The same is true for teeth. if you wait until they hurt then it is usually far more difficult and expensive to fix them than if you fix them as soon as a problem is detected. This is why dentists recommend regular checkups.

First let’s look at what a cavity (scientific term: dental caries) is.  A cavity is basically a bacteria filled hold in a tooth. It starts with microscopic damage to the surface of the tooth by acid secreting bacteria. Once enough surface is dissolved by the acid that the bacteria can actually enter into the tooth, they do. At this point the bacteria continue to proceed deeper and deeper into the tooth dissolving the tooth away from the inside out. None of this is painful. Rarely does it even cause sensitivity. Rarely can it been seen without the help of x-rays. Once a hole has formed in the tooth, nothing (not even brushing, flossing, or fluoride) will stop this process except removing the decay and then covering the hole with a protective material (i.e. getting a filling).

So when does a cavity hurt? Eventually the bacteria penetrate very deep to the middle of the tooth which contains a soft tissue called dental pulp. When the bacteria become very near this tissue, sensitivity may begin. When the bacteria enter this tissue it invariably dies. It is trapped in a hard space and when infected tries to swell like any other part of the body does when infected. In the hard space it cannot swell but instead increases in pressure cutting off its own blood supply. Then it dies. The process of death of the dental pulp is extremely painful. After death it feels better, but now the tooth is full of dead, rotting tissue. Sometime later enough bacteria from this rotting tissue leak out of the tooth into the bone to cause an abscess in the bone.  At this point it become very painful again. The abscess may go through cycles of being very painful and then not hurting at all only to repeat again. Whether an abscessed tooth is hurting or not, it is still dangerous and the infection is still there. The periods of pain relief come from the abscess finding a way to drain its pus into the mouth relieving the pressure and the pain. Eventually the drain clogs up and it starts to hurt again. The only way to fix it is to get the dead, rotten tissue out by either removing the tooth or cleaning out the inside of the tooth
(called a root canal procedure).

The bad new is that once the tooth begins to die it is going to die. It cannot heal because of the decreasing blood supply. The tooth may not ever experience increased sensitivity prior to starting to die. If it does, it will usually only be for a short period of time before the dying process begins. Therefore, if you wait until it hurts to fix it you are very likely to need a root canal procedure. Also because you have waited for it to become a very big hole instead of a little hole you will probably need a build-up and a crown (cap) as well.  Worst of all, a tooth that gets a root canal and crown in a young person (yougner than middle age) is unlikely to last the rest of the person’s life.

It is impossible to predict how long it will take a small cavity to go from just starting out to needing a root canal. Cavities progress at different speeds depending on diet, oral hygiene, and saliva composition and amount. Some may progress to tooth ache in just a few months and some may take years. Therefore there is no way to say this tooth has a cavity but won’t need a filling until such and such date.

So when do we see cavities without an x-ray? The short answer is only when they are really big. Your dentist can probably see visual clues of cavity presence before a lay person because he or she looks at cavities all day every day. However, even your dentist cannot see many cavities visually until they are pretty large. The outside of the tooth is a shell of hard material called enamel (a mineral crystal -basically rock coating your tooth). The inside of the tooth is made of dentin which is similar to bone. While dentin is also hard, it is much softer than enamel. It is also much easier to dissolve in acid. Therefore the cavity enters the tooth through a microscopic hole in the enamel and then spreads out widely in the softer dentin.  The hole in the dentin may be much, much bigger then the hole in the enamel. What looks like a little black dot the size of a pinhead on the surface of your tooth can easily be a huge hole the size of half your tooth underneath.

Large cavities that cannot be seen by visually examining the teeth.

The x-ray on the left shows two teeth that are both nearly half destroyed by cavities. Also the tooth on the right is most likely already infected and will require a root canal, build-up, and crown. The cavities in both teeth were not readily apparent on visual examination.

X-rays show calcified materials very well (bones and teeth). Since cavities are basically a process of calcium loss due to acid attack, they also show very well as a specific spot of no calcification within the normal calcification of a tooth. We can detect a cavity on x-ray before we can see it visually. When we do we recommend a filling. The earlier we can detect a cavity, the smaller the filling to fix it will need to be. A small filling will last you much longer than a large filling. A filling generally ranges from $100-$200.  A root canal, build-up, and crown generally ranges from $1500-$2500. This is why dentists recommend filling teeth that don’t hurt. It can avoid the need for root canals and crowns. It can allow you to have less invasive small fillings rather than large ones. It can save you thousands of dollars down the line.  Most importantly it can help ensure a lifetime of healthy service from your teeth.

So next time your dentist tells you you need a filling, remember this post. I know the natural reaction is to think, “Yeah right, my tooth doesn’t hurt. This dentist just wants to make money off me.” Try to remember this post. The dentist actually makes a lot more money, if he or she let’s you wait until it hurts. A root canal, build-up, and crown cost a lot more than a filling. So if your dentist brings up your cavities early before they hurt; he or she probably has your best interests at heart.

Did this post on cavities make your teeth itch? This dentist in Edmond, OK would love to hear about it. Please comment on this post on our Facebook (

If you are looking for an Edmond dentist, we are excited to accept new patients! Call the office at 405-960-0290 today for an appointment. You can always email me at
I answer my own emails!

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