Why remove my wisdom teeth? They’re not bothering me!

It’s a fair objection.  If a body part is not symptomatic, why remove it?  After all, I would have objected if a surgeon had wanted to take remove my appendix prophylactically, before I developed appendicitis.  Why should wisdom teeth be any different?  Why should third molars (wisdom teeth) be removed before symptoms occur?

It is because in most cases, the damage from wisdom teeth occurs gradually, with no symptoms until very late.  But it nearly always occurs- either damage from gum disease, bone cysts or from cavities on the back of 2nd molars.

The gums around the wisdom teeth are usually not the type most resistant to gum disease.  Added to this is the fact that the wisdom teeth usually erupt in the corner of the jaw, allowing gums to partially cover them.  These two factors predisposes patients to have gum disease around wisdom teeth.

Now we would not worry if wisdom teeth lost bone and ligament support around them until they got loose and fell out.  The problem is that if wisdom teeth are left in, periodontal destruction almost always occurs between the wisdom teeth and 2nd molars in front of them.  When the wisdom teeth are finally lost, the second molars are often weakened due to ligament and bone loss.  Often, when patients maintain their wisdom teeth over many years, they end up losing both the wisdom teeth AND the 2nd molars due to gum disease.

Wisdom teeth often jeopardize 2nd molars in another way.  Often food gets trapped between wisdom teeth and 2nd molars and cause decay. My patient histories are replete with many cases like this:

 wisdom teeth dental decay

This patient developed decay on the back of his 2nd molar (black spot on the right of the middle  tooth) because of his wisdom tooth (on the right.) By the time he realized it, the decay had infected the nerve. This meant a root canal, buildup filling, and crown were necessary on the  2nd molar in order to save it.

Most patients have trouble cleaning between the rest of their teeth with floss.  How much more difficult it is to clean around wisdom teeth! Honestly, I have met few patients who can do it well.

Should unerupted wisdom teeth also be removed?

A third, rarer reason to remove wisdom teeth is to prevent cysts and tumors in the bone.  Around each unerupted wisdom tooth is a sac of cells which formed the tooth, call the dental follicle.  Especially in the lower jaw, these cells sometimes expand, forming a tumor which can destroy a big part of the lower jaw.

The presence of an impacted wisdom tooth may also weaken the jaw structurally.  Sometimes I have seen accident victims in which the jaw broke at the location of an impacted wisdom tooth.  Had the space been filled with sturdy bone, the jaw fracture might not have happened.

Just because a wisdom tooth is unerupted, does not mean it will stay that way. Wisdom teeth can sometimes erupt and cause inconvenient problems later in life- even if a patient has complete dentures!

Are there any situations where you might leave wisdom teeth in the mouth?

Yes, there are a few.

When patients have four premolars removed for orthodontics, all molars are positioned farther forward in the mouth. Occasionally, there is enough room for the third molars to erupt and be maintained in good health.

Another instance is when 1st or 2nd molars are lost.  Occasionally, the wisdom teeth may be moved by orthodontics to be good substitutes for the lost teeth.  But it is a very difficult movement, except in young patients.

When patients lose their first and second molars, wisdom teeth can be used to anchor a removable partial denture, especially on the lower arch. Wisdom teeth are often not shaped very well for this use, but it can be better than resting the partial denture on gums alone.

In elderly individuals, especially those on drugs to prevent osteoporosis, I might leave wisdom teeth alone, whether unerupted or not.  Sometimes the surgical risk outweighs the benefits of extraction in older patients.

If they are so useless, why do humans still have 3rd molars?

The trend has been toward shorter jaws in mankind.  The higher apes have plenty of room for 3rd molars, and some even have 4th molars as well.  Through the years, man’s jaws have become shorter, but the size of his teeth has stayed the same.  The result is not enough room for the wisdom teeth, which are the last to erupt in the mouth.

 Kim Henry, D.M.D.

 July 25, 2007

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What Causes Cavities?

When I ask patients with cavity problems to guess the origin of their problem, I occasionally get answers like these:

“It was some medicine I took as a child.”

 “My teeth were fine until I had my children.  They sucked all the calcium out of my teeth when I was pregnant. Then my teeth got weak and decayed.”

 “My parents had dentures.  I guess I inherited bad teeth.”

 “It must be from not brushing my teeth right.”

 Let us look together and see how decay really gets started, then go on to investigate how we may prevent it!

What is decay?

Teeth are made of minerals, and are the hardest organs of the body- much harder than bone!  Decay is a process whereby the hard enamel outside of a tooth is dissolved by acid.  Once decay gets through the enamel, the same acid dissolution progresses very quickly in the inner dentin of the tooth. If the patient does not get the cavity filled, decay invade the tooth root (containing nerves) and a toothache results.

So where does this acid come from?

It can come from a couple of sources.  The most common is from bacteria living inside our mouths.  Many of these sugars utilize for energy, and produce lactic acid as a by-product. It is primarily this acid which acts to dissolve teeth.  Bacteria can turn dietary sugars into lactic acid in only 20 minutes. Unless the mouth is rinsed or cleaned, this acid hangs around to dissolve teeth for a whole hour!  So you can see that a child who ingests candy most of the day will have an acid mouth all day, an inevitably have move than a few cavities!  An adult who sips sweetened coffee most of the workday will likely suffer from the same fate.

But adults frequently get acid more directly- by drinking soda pop!  Few people realize what strong acids carbonated beverages really are!  Carbonated drinks are such potent acids that they can dissolve teeth directly whether the soda is “diet” or has sugar in it.  I would estimate that 75% of adult decay I see is the direct result of excessive soda drinking.  And as if that were not enough, too many sodas can contribute to stomach ulcers and even osteoporosis.

dental tooth decay Excessive daily soda pop intake caused characteristic tooth decay around gums.

Other sources of acid we sometimes encounter:

Chronic vomiting, as seen in bulimia and some other disorders, can erode teeth and also cause cavities.

We have noted lately many cases of gastric reflux, where small quantities of stomach acid enter the mouth.  This causes rampant destruction in your mouth, and should be controlled by prescriptions or surgery!

Don’t some medical conditions expedite decay?

Yes. Although not directly a cause of decay, any condition which dries the mouth can make your teeth more susceptible to it. Examples are doses of radiation to the head, using certain antidepressants, and antihistamines. We find that people that are mouth breathers are prone to more decay than those who can breathe normally through their nose.

Fluoride- our two-edged sword in fighting decay:

Even should physicians be unable to treat the above medical conditions, we still are able to stop decay- provided we have patient cooperation and fluoride.

Fluoride actually works two ways.  It has a toxic effect on decay causing bacteria. It also hardens tooth enamel and makes it more resistant to acid attack.  Interestingly, fluoride strengthens bone in the same way it strengthens teeth.  Physicians sometimes use fluoride supplement to treat osteoporosis.

For adults with decay problems, we often prescribe a fluoride gel to brush on the teeth at night just before bed, and a fluoride mouth rinse in the morning.  For really tough cases, including patients who have uncontrolled gastric reflux, we make custom trays to wear with fluoride at night.  With this heavy-duty preventive treatment, few patients get cavities!

Kim Henry, D.M.D.