Periodontal Anatomy – Gingival Margin
The terminal edge of gingiva (gums) that surrounds the teeth is known as the gingival margin (marginal gingiva). Roughly half of individuals have a gingival margin that is demarcated from the adjacent gingiva by a shallow linear depression (free gingival groove). The shallow depression, located on the gingiva’s outer surface, has no correspondence to the depth of the gingival sulculus but does to the apical border of the junctional epithelium. Depth of the outer groove varies based on the oral cavity area; it is prominent on mandibular anteriors and premolars.
Width of the gingival margin ranges from .5-2.0 mm from the free gingival crest to the attached gingiva and follows the scalloped pattern created by contour of the cementoenamel junction of the teeth. When compared to that of the attached gingiva, the gingival margin appears more translucent but has similar clinical appearance including firmness, dullness, and pinkness. The gingival margin lacks the presence of stippling and the tissue is mobile or not attached to the surface of the underlying tooth. Stabilized by gingival fibers, marginal gingiva do not have any bone support.
Gingival Retraction or Recession
If a lateral movement of the gingival margin away from the tooth surface happens, gingival recession or gingival retraction occurs. Should the movement be spontaneous or unintentional, it is typically referred to as gingival recession. In these cases it could signify the presence of underlying inflammation, pocket formation, or displacement of the gingival margin away from the teeth through surgical, mechanical, or chemical means. When the movement is intentionally performed using chemical, electrical, or mechanical means as part of a surgical dental procedure, it is known as gingival retraction. Both gingival retraction and gingival recession can result in exposed tooth roots.
Treating Gingival Retraction or Recession
Gingival Retraction Paste: shown to be the most successful method in providing a dry field and causing the least amount of damage to the surrounding periodontium. Involves placing a specially designed tip vertically into the gingival sulcus (natural space between the tooth and surrounding gum tissue) to retract the tissue before injecting the paste to fill the sulcus completely. The paste can be used alone or in conjunction with cotton pellets, cords, or specialized caps to assist with packing into the sulcus and keeping the field dry. After about two minutes the pasts is removed completely resulting in a clean, dry preparation with a clearly visible margin.
Gingival Retraction Cord: an instrument typically used by dentists during the preparation of the teeth for dental crown or dental bridge procedures. Its main purpose is to give the doctor a clear working view of the tooth prior to taking a dental impression. The retraction cord is gently inserted below the gumline, into the gingival sulcus, and around the tooth being prepared for the bridge or crown. When compared to gingival retraction pastes, gingival retraction cords are more effective at displacing gingival tissues but cause more damage to the periodontium. As such, cords are generally recommended in cases where the patient has thick periodontium present.