Anatomy and Histology

Posted on March 4, 2019

To better understand gum disease let’s take a look at the anatomical and histological structures of teeth as well as the gum tissue and bone that surrounds the teeth.  We don’t need an in-depth, specialized education.  We just need to have a basic, generalized understanding of the oral anatomy and histology.

As humans, we all use our teeth to bite and chew food.  They are the first step to digestive system.  The front teeth (incisors and canines) are meant to cut and tear food, while the back teeth (molars) are meant to grind and mash food. The food is then propelled to the back of the mouth by the tongue, and swallowed.

If you’re missing molars, the front teeth are then given the double duty of cutting and mashing.  Mashing food with your front teeth is not good, as it speeds up bone loss around those teeth.  That’s why is is always recommended that any time a tooth is missing, it should be replaced right away.

The human tooth consists of a crown and a root.  The crown is typically the part of the tooth above the gums that you see when you look at your teeth.  It consists of the outermost layer of enamel.  Enamel is the hardest and most mineralized substance in the human body.  Just beneath the enamel, and comprising the bulk of the tooth, is a hard, dense substance called dentin.  Beneath the dentin, in the center of the tooth, lies an area comprised of living cells, connective tissue, blood vessels and nerves called the pulp.

The root of the tooth is typically not visible, as it is below the gums and, therefore, below the bone.  The region of the tooth where the crown meets the root is called the neck of the tooth.  In a healthy mouth, your gum tissues are tight around the necks of the teeth.  Surrounding the roots of each tooth is the alveolar bone of the maxilla (upper jaw) and mandible (lower jaw).  In a healthy mouth, bone levels come up high around the necks of the teeth and the bone level is even throughout the entire mouth.

Between your teeth and gums is a small valley called the gingival sulcus.  It extends from the top of the gingiva (known as the gingival crest) to the area where the periodontal ligaments attach it to the root of the tooth, and it travels all the way around the tooth.  Prior to cleaning your teeth, your dental hygienist should measure 6 points around each tooth to see how deep the sulcus is.  The depth of the sulcus is recorded by using a periodontal probe.  Ideally, the depth of the sulcus should measure 3 mm, and it should be probed and recorded every 12 months.  If it measures deeper than 3 mm, we no longer call it a sulcus.  At 4 mm in depth, we now refer to it as a periodontal pocket.  At 6 mm in depth, it is now twice as deep as it ought to be, and we refer to it as a deep pocket.  Whereas shallow pockets are bad, deep pockets are really bad.  Your goal with healthy gums is to have no measurements above 3 mm.  You also want them to not bleed or exude pus when you clean them or when the measurements are recorded.

The final phenomenon that we want to focus on in our crash course of dental anatomy and histology is a saliva-like fluid known as gingival crevicular fluid.  Gingival crevicular fluid flows from the gingival sulcus or periodontal pocket, and is believed by some authorities to be an inflammatory exudate and by others (like me) to be a cleansing material to flush debris out of the sulcus/pocket.  In the case of healthy gingiva, the flow rate of gingival crevicular fluid is minimal-to-absent and it increases dramatically as the gingival tissues become more irritated and inflamed.


  1. Healthy gums don’t bleed when they are probed or when your teeth are professionally cleaned.
  2. Measurements of 1 to 3 mm are good.
  3. Measurements of 4 to 5 mm are bad.
  4. Measurements of 6 mm and above are really bad.
  5. Bleeding is bad.
  6. Pus is really bad.
  7. The rate of crevicular flow increases as the gingival tissues become more irritated and inflamed.