RETRACTED: A Practice‐Based Case Series Evaluation of a Porcine Collagen Matrix to Thicken Soft Tissue, Increase Keratinized Tissue, and Improve Esthetics Around Existing Dental Implants (Clin Adv Periodontics March 28, 2012 [published online ahead of print]; doi: 10.1902/cap.2012.110077) - Retraction Notice | RetractBase