title: Soft tissue augmentation around osseointegrated and uncovered dental implants: a systematic review.
abstract: OBJECTIVE
  The aim was to compile the current knowledge about the efficacy of different soft tissue correction methods around osseointegrated, already uncovered and/or loaded (OU/L) implants with insufficient soft tissue conditions. Procedures to increase peri-implant keratinized mucosa (KM) width and/or soft tissue volume were considered.
  
  
  METHODS
  Screening of two databases: MEDLINE (PubMed) and EMBASE (OVID), and manual search of articles were performed. Human studies reporting on soft tissue augmentation/correction methods around OU/L implants up to June 30, 2016, were considered. Quality assessment of selected full-text articles to weight risk of bias was performed using the Cochrane collaboration's tool.
  
  
  RESULTS
  Overall, four randomized controlled trials (risk of bias = high/low) and five prospective studies (risk of bias = high) were included. Depending on the surgical techniques and graft materials, the enlargement of keratinized tissue (KT) ranged between 1.15 ± 0.81 and 2.57 ± 0.50 mm. The apically positioned partial thickness flap (APPTF), in combination with a free gingival graft (FGG), a subepithelial connective tissue graft (SCTG), or a xenogeneic graft material (XCM) were most effective. A coronally advanced flap (CAF) combined with SCTG in three, combined with allogenic graft materials (AMDA) in one, and a split thickness flap (STF) combined with SCTG in another study showed mean soft tissue recession coverage rates from 28 to 96.3 %. STF combined with XCM failed to improve peri-implant soft tissue coverage.
  
  
  CONCLUSIONS
  The three APPTF-techniques combined with FGG, SCTG, or XCM achieved comparable enlargements of peri-implant KT. Further, both STF and CAF, both in combination with SCTG, are equivalent regarding recession coverage rates. STF + XCM and CAF + AMDA did not reach significant coverage.
  
  
  CONCLUSIONS
  In case of soft tissue deficiency around OU/L dental implants, the selection of both an appropriate surgical technique and a suitable soft tissue graft material is of utmost clinical relevance.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Spitalstrasse, 6000, Lucerne, Switzerland. renzo.bassetti@luks.ch.
authors.forename: Renzo G
authors.initials: RG
authors.lastname: Bassetti
authors.affiliation: Department of Periodontology, University of Bern, Bern, Switzerland.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Stähli
authors.affiliation: Department of Oral and Maxillofacial Surgery, Lucerne Cantonal Hospital, Spitalstrasse, 6000, Lucerne, Switzerland.
authors.forename: Mario A
authors.initials: MA
authors.lastname: Bassetti
authors.affiliation: Department of Periodontology, University of Bern, Bern, Switzerland.
authors.forename: Anton
authors.initials: A
authors.lastname: Sculean
mesh_terms: D003238:Connective Tissue / Q000637:transplantation; D015921:Dental Implants; D005893:Gingivoplasty / Q000379:methods*; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000534:rehabilitation; D010519:Periodontium / Q000601:surgery; D013524:Surgical Flaps; D014727:Vestibuloplasty / Q000379:methods
chemical_list: D015921:Dental Implants
keywords: Dental implant; Free gingival graft; Peri-implant keratinized attached mucosa; Soft tissue recession; Soft tissue volume; Subepithelial connective tissue graft; Vestibuloplasty; Xenogeneic collagen matrix