Periodontal Anatomy – Free gingival margin
The free gingival margin is located in the oral cavity and is a term used to describe the interface between the sulcular epithelium and the epithelium. This specific interface is present at the most coronal point of the gingiva. This is also referred to as the crest of the marginal gingiva.
As a result of the short portion of the gingiva which exists above the height of the underlying Alveolar process of maxilla, the free gingiva, it is moveable and is not bound down to the periosteum which surrounds the bone. Because of the presence of gingival fibers, such as the dentogingival and circular fibers, however, the free gingiva remains next to the surface of the tooth. This process takes place unless the free gingiva is pushed away with the use of a periodontal probe or a toothbrush.
Gingival Retraction or Recession
Gingival retraction or recession occurs when there is a lateral movement of the gingival margin away from the surface of the tooth. This is usually called gingival retraction and is intentionally done. In these cases, it is performed through the use of mechanical, chemical, or electrical methods to complete specific dental surgical procedures. In the dental field, it is usually called gingival recession as a spontaneous or non-intentional presentation. It may indicate the presence of an underlying inflammation, the formation of a pocket or displacement of the marginal gingivae away from the tooth via mechanical, chemical, or surgical means. Similarly to gingival recession, the process may expose the tooth’s roots.
The use of gingival retraction paste has proven to be one of most successful methods used to provide a dry field and impose the least amount of damage to the surrounding periodontium. Compared to a retraction cord, however, does not have the ability to retract the gingival tissues.
Gingival Retraction Cord
A retraction cord, while more damaging to the gingival tissues, more effectively displaces the gingival tissues. As a result, it is recommended in cases where there is a thick periodontium. Without the addition of any chemicals, such as epinephrine or a sulfate compound, the cord does not produce haemostasis at the sulcus on its own.
The process of completing periodontal probing continues to be a key method used to diagnose periodontal disease. Periodontal probing is performed hundreds of thousand times a day in dental offices across the globe. A probing depth alone, however, does not fully expose the complete status of the area which is being measured. Clinicians require additional information regarding the periodontal tissue’s health which complements the data obtained through probing.
While probing depths are valuable and important, if this measurement is exclusively used, the amount of bone support for the tooth can be miscalculated with an over or under estimation. For example, the probing depth does not take into account gingival recession, overgrowth or a change of the marginal gingiva which could be associated with swelling of the tissue.
There are two different measurements which are commonly used to calculate the clinical attachment level (CAL). This includes the probing depth and the distance from the gingival margin to the cemento-enamel junction (CEJ).
It is important to note, that the gingival margin can be found in one of following three locations:
- The CEJ can be coronal to the gingival margin. This is called recession and is a simple measurement.
- The CEJ can also be at the same level as the gingival margin.
- In some cases, the gingival margin can extend substantially over the CEJ and make it difficult to obtain an accurate measurement.
When combined, the probing depth, in addition to the distance from the gingival margin to the CEJ, calculates the clinical attachment level