Clinical attachment level change as an outcome measure for therapies that slow the progression of periodontal disease.

Attachment levels are excellent indicators of past destruction of the periodontal attachment apparatus and can be used to monitor the progression of periodontitis. They have been used in clinical trials to monitor the efficacy of a variety of therapeutic modalities that may either slow the progression of periodontal disease or allow for regeneration of lost attachment and supporting structures. Inherent difficulties in accurately assessing attachment levels include inflammation, which causes coronal displacement of the gingival margin without a concomitant migration of the dentogingival epithelium to a level apical to the cementoenamel junction, and recessions, in which an obvious loss of attachment has occurred, but there is no increase in probing depth. Attachment level measurements are more frequently used as clinical end-points in clinical trials than by private practitioners to determine the periodontal status of patients and to monitor patient responses to periodontal therapy. Clinical attachment level measurements have been used in clinical trials to evaluate a systemic host modulatory agent, demonstrating their utility as surrogate markers of efficacy.