title: Changes of the peri-implant soft tissue thickness after grafting with a collagen matrix.
abstract: BACKGROUND
  The aim of this study was to determine the treatment outcome of the use of a porcine monolayer collagen matrix (mCM) to increase soft-tissue volume as a part of implant site development.
  
  
  METHODS
  Implants were placed in single sites in 27 patients. In the test group, mCM was used for soft-tissue augmentation. No graft was placed in the control group. Soft-tissue thickness (STTh) was measured at the time of surgery (T0) and 6 months postoperatively (T1) at two sites (STTh 1, 1 mm below the gingival margin; STTh 2, 3 mm below the mucogingival margin).
  
  
  RESULTS
  Significant increases (P< 0.001) in STTh (STTh 1 = 1.06 mm, 117%; STTh 2 = 0.89 mm, 81%) were observed in the test group. Biopsy results showed angiogenesis and mature connective tissue covered by keratinized epithelium.
  
  
  CONCLUSIONS
  Within the limitations of this study, it could be concluded that mCM leads to a significant increase of peri-implant soft-tissue thickness, with good histological integration and replacement by soft tissue and may serve as an alternative to connective tissue grafting.
authors.affiliation: Department of Oral Hygiene, Claudiana University of Applied Health Sciences, Bolzano, Italy.
authors.forename: Gregory-George
authors.initials: GG
authors.lastname: Zafiropoulos
authors.affiliation: Division of Periodontology, School of Dentistry, Catholic University, Rome, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Deli
authors.affiliation: Department of Periodontology, School of Dentistry, Loma Linda University, Loma Linda, CA, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Hoffmann
authors.affiliation: Department of Oral Surgery, School of Dentistry, University of Duesseldorf, Duesseldorf, Germany.
authors.forename: Gordon
authors.initials: G
authors.lastname: John
keywords: Augmentation; collagen matrix; connective tissue; tissue thickness; tissue volume