January 15, 2021
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It’s what’s inside that counts!

By: George Malkemus
January 25, 2019

Many first impressions are formed by the whiteness and straightness of your teeth. This external view of your teeth is important, but what’s inside your teeth is even more important to your overall health and the attractiveness of your smile.  From the outside, each tooth looks like a solid white object, but actually teeth are composed of several layers of complex living tissues, which include enamel, dentin, pulp and cementum.


Enamel is the white, thin [only 1 to 2 mm thick] outermost layer of a tooth.  It is the part of your tooth that you see above the gum line.   Enamel is the hardest substance in your body and the second hardest substance in nature. Only diamonds are harder. Actually, I use small diamonds burs to be able to drill through enamel. Teeth are a major find in the fossil record, due to enamel’s hardness being the last feature to dissolve.

Enamel provides strength for biting and chewing and it protects the inner layers from plaque and bacteria that lead to decay. Though hard, enamel is eroded by acid from acidic foods, acid reflux and decay producing bacteria. Bacteria lives in the pits and grooves on the enamel and uses food particles, particularly sugar, to eat through the hard, but thin layer of enamel by secreting acid.  If decay is caught early in the outer enamel layer only, often a filling can be placed without numbing since enamel is not life tissue and has no nerves connections.


Dentin is the next layer under the enamel inside your tooth.  Rather yellow in color, dentin contains millions of tubules, which are fluid filled and connect to the nerves in the pulp. Dentin is softer than enamel and provides support for it, acting like a shock absorber to take the impact of biting and chewing. When a cavity develops, it breaks through the enamel and attacks the dentin, which can cause sensitivity.  Unlike enamel, dentin is live tissue and bacteria can quickly eat into it, using the dentin as a food source.  If decay is removed while still in the outer two layers of enamel and dentin, usually a filling can be placed with good results.  Numbing is usually needed when decay is in the dentin.


Pulp is the innermost layer, which includes the nerves and blood supply for a tooth. These soft tissues extend from the pulp chamber at the top of the tooth, down through the root canals into the tooth roots. If decay reaches the pulp, bacteria infect these vital tissues.  The infection can quickly spread and travel down the root, forming an abscess, which is an infection in the bone.  Once decay reaches the pulp, root canal therapy is necessary.


Cementum covers the roots of the teeth on the outside of the roots. This extremely thin layer of tissue “cements” your teeth to the bone. The roots of your teeth (the parts of your teeth below the gum line) also contain blood vessels and nerves that connect your teeth to the nerves and blood vessels of your jawbone. Cementum is similar to dentin, being alive and softer than enamel.  When gums recede, cementum becomes exposed and often the tooth becomes sensitive.  Also decay can more easily begin in the soft exposed cementum.  If decay is caught early, a filling can be bonded on the root surface to protect the tooth and stop sensitivity.

Disease and decay that reach the roots are extremely serious and painful.  Once in the root, infections can spread to the jawbone and cause a painful dental abscess.  That’s why it’s important to have both the outsides and the insides of your teeth examined.  And that is why dental x-rays are needed to see the changes in the insides of teeth.

X-rays: A safe view inside your teeth

Dental x-rays are taken as a regular part of a dental examination. In my office, we use digital x-rays that are instantaneously made part of the patient’s computer record. Digital x-rays have the added benefit of using 80 percent less radiation. The sensitive digital equipment quickly and accurately targets only a specific area of the mouth.  The radiation level is very low, equal to less than 5-minutes exposure to the sun.

Different types of x-ray images help identify areas of decay, worn-out fillings, cracks, tartar, periodontal disease, bone infections, impacted wisdom teeth, long or crooked roots, abscesses, cysts, sinus problems and bone cancer.

Depending on your age and your dental health situation, different kinds of x-rays are used, including:

Bitewing x-rays: These are the most common type of x-rays. They capture images of your upper and lower teeth above the gum line simultaneously.  Usually taken once a year, bitewing x-rays best show decay between the back teeth.  Decay between the teeth is caused by lack of flossing and can go undetected without regular, bitewing x-rays. 

Full series of x-rays: Using 18 different locations, these give a complete picture of your mouth.  A full series is usually taken during your first new patient examination, and recommended every three to five years.

Periapical x-rays: These give an excellent view of your entire tooth, including the roots, bone loss, decay and abscesses. A periapical x-ray is taken when a patient has a toothache and during root canal therapy.

Panographic x-rays: These give us a complete picture of your entire mouth in one image, including wisdom teeth, the sinuses and the jawbone.  A panograph is usually necessary for wisdom teeth removal, implant placement and orthodontic treatment. Often a panograph along with bitewings can be used in place of a full mouth series. 

Cone-beam CT scan:  This gives a 3-D image of the jawbone, showing the density, width, and height of the bone, as well as the location of vital nerves and tissues. Cone-beam CT scan is necessary for involved implant cases and surgical orthodontics.

Now that you’ve learned a bit about your teeth from the inside out, take good care of them from the outside in!  Have regular dental cleanings, examinations and necessary x-rays.


George Malkemus has a Family and Cosmetic Dental Practice in Rohnert Park at 2 Padre Parkway, Suite 200. Call 585-8595, or email  Visit Dr. Malkemus Web site at