Injectable collagen implant: histopathologic identification and longevity of correction.

This prospective study reports the results of the longevity of the correction achieved in 312 patients receiving injectable collagen implant and the histopathologic identification of the implant in the six who experienced reactions at the treatment sites. In reporting results in cosmetic patients, certain ones can be considered objective or factual, and other must be judged subjective. This study reports both kinds of results and proposes a new theory to explain the duration of the improvement.