The most common diseases of the gum and soft tissues of the mouth are strongly associated with the formation of bacterial plaque (2:53). Growing evidence strongly suggests that the toxins produced by these bacterial growths can trigger local inflammation of the gingival tissues. A number of dental scientists now believe that the constant challenge of bacterial plaque causes an allergic reaction in the gingival tissues and finally produces periodontal disease (4:55). When plaque and tartar are firmly established on the teeth and beneath the gum, professional prophylaxis, including subgingival scaling, will be needed to remove these deposits (2:54).
In fitting a crown to a specific location, the relative health of the gingival tissues surrounding the crown site must be considered. Crowns are usually proposed as a restoration when a tooth is either very severely destroyed by dental caries or trauma or, in the case of posterior teeth, if root canal therapy has ensued. Crowns must therefore be custom made to fit properly, providing proper occlusion, contour, and contacts with adjacent teeth (5:95). Prior disease factors, caused by existent gingival conditions, must be considered before a crown is applied. Likewise, if proper care is not taken while applying the crown, or because of errors in manufacture or judgment, trauma can occur.
If the optimum health of gingival tissues involved cannot be guaranteed before the dentist or technician makes an impression, than one can almost expect that crown margins will deviate from established norms. Gingival tissues need to be healthy before a technician can establish final margin locations (5:95).
Recession of the gingival tissues can occur for other reasons. Trauma can occur during retraction of gingival tissues, while technicians are removing plaque or calculus. Trauma can occur while technicians or dentists are installing crowns. Usually, cessation of the activity, follow...