Dental Education Lecture: What are Gum Diseases?

In lectures Flossing and Why We Need to Floss, we discuss necessity of regular oral hygiene including floss to prevent cavities and gum diseases.  In this lecture, we use illustrations to show what gum diseases are.

Fig.1 shows two lower front teeth with normal gums (pink).  Normal gums have feather-thin end (pointed by single arrow).  Double arrows point to the bottom of the gum groove.

When we ignore oral hygiene including flossing for a while, plaque (yellow, Fig.2) is deposited along surfaces between two neighboring teeth.  Accumulation of plaque (produced by germs) can cause inflammation of the adjacent gums.  The latter become reddish, easily bleeding when we brush, and swollen.  The terminal end of gums starts to recede and becomes blunt and puffy (pointed by single arrow).  The bottom of gum groove (double arrows) remains basically unchanged as compared to that in Fig.1.  This mild form of gum disease is called gingivitis.  We may have bad breath.  If we seek prompt dental treatment to remove plaque and begin to practice good oral hygiene, inflammation will subside.  Our gums will return to normal condition as shown in Fig.1.

If we keep ignoring oral hygiene and do not follow doctor's suggestion and treatment, more plaque is accumulated (yellow, Fig.3).  Gum recession is more severe.  Compare the level of single arrow in Fig.3 vs. those in Fig.1 and 2. The bottom of gum groove begins to change and drops down.  It is easier for gums to bleed during brushing and even eating.  Bad odor is more severe and embarrassing. In brief, our gum condition gets worse.  The severe form of gum disease is called periodontitis.  The distance between single and double arrows is the depth of pocket (Fig.1-3).  The pocket depth is 2-3mm in normal gums and gingivitis.  The pocket is more than 3 mm and as deep as 10 mm in periodontitis.  The increased pocket depth is one of two main features of periodontitis.  

The other feature of periodontitis is loss of alveolar bone.  Fig.4 is enlargement of gums shown in Fig.1.  Inside this type of normal gums (pink) is alveolar bone (black).  The alveolar bone in fact surrounds the root of our individual teeth and keep them stable.  In gingiviits, the alveolar bone remains essentially unchanged (Fig.5).  By contrast, the alveolar bone surrounding the teeth with periodontitis is lost in three dimensions.  In two-dimensional illustration, bone loss in periodontitis is both vertical (up-and-down) and horizontal (right-to-left) (Fig.6).  The more bone is lost, the looser our teeth are.  Once the bottom of gum groove drops and bone is lost, they are not easily reverted to normal with treatment.  To make situation worse, these two irreversible changes are not noticeable to us.  When we have pain associated with gum diseases, they are fairly late in stage and are resistant to treatment with poor outcome.  Therefore, it is critical for us to take care of ourselves before we realize that we have tooth or gum problems.  Is it time for us to pick up a piece of dental floss?

Xin Wei, DDS, PhD, MS 1st edition 01/29/2009, last revision 03/20/2010