title: Clinical evaluation of a collagen matrix to enhance the width of keratinized gingiva around dental implants.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the effect of collagen matrix with apically positioned flap (APF) on the width of keratinized gingiva, comparing to the results of APF only and APF combined with free gingival graft (FGG) at the second implant surgery.
  
  
  METHODS
  Nine patients were selected from those who had received treatments at the Department of Periodontics, Chosun University Dental Hospital, Gwangju, Korea. We performed APF, APF combined with FGG, and APF combined with collagen matrix coverage respectively. Clinical evaluation of keratinized gingival was performed by measuring the distance from the gingival crest to the mucogingival junction at the mid-buccal point, using a periodontal probe before and after the surgery.
  
  
  RESULTS
  The ratio of an increase was 0.3, 0.6, and 0.6 for the three subjects in the APF cases, 3, 5, and 7 for the three in the APF combined with FGG case, and 1.5, 0.5, and 3 for the three in the APF combined with collagen matrix coverage case.
  
  
  CONCLUSIONS
  This study suggests that the collagen matrix when used as a soft tissue substitute with the aim of increasing the width of keratinized tissue or mucosa, was as effective and predictable as the FGG.
authors.affiliation: Department of Periodontology, Chosun University School of Dentistry, Gwangju, Korea.
authors.forename: Kang-Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Byung-Ock
authors.initials: BO
authors.lastname: Kim
authors.forename: Hyun-Seon
authors.initials: HS
authors.lastname: Jang