title: Randomized controlled clinical study comparing a volume-stable collagen matrix to autogenous connective tissue grafts for soft tissue augmentation at implant sites: linear volumetric soft tissue changes up to 3 months.
abstract: OBJECTIVE
  To test whether or not the use of a volume-stable collagen matrix (VCMX) results in soft tissue volume increase at implant sites non-inferior to an autogenous subepithelial connective tissue graft (SCTG).
  
  
  METHODS
  In 20 patients, soft tissue augmentation at implant sites was performed using VCMX or SCTG. Casts obtained prior to augmentation (BL), at 30 (FU-30) and 90 days (FU-90) were digitized and transferred to stereolithography (STL) files. BL, FU-30 and FU-90 STL files were superimposed and linear volumetric changes evaluated in crestal and buccal regions of interest (ROI). Descriptive analysis was computed for both groups and a test for non-inferiority was performed.
  
  
  RESULTS
  The median linear changes from BL to FU-90 in the crestal ROI amounted to 0.175 mm (0.06; 0.51) for VCMX (p = 0.002 over time) and to 0.51 mm (0.23; 0.94) for SCTG (p = 0.129). The differences between the two groups were not significant (p = 0.287). The respective values in the buccal ROI were 0.59 mm (0.26; 1.06) for VCMX (p = 0.002) and 0.94 mm (0.66; 1.13) for SCTG (p = 0.004). The differences between the two groups were not significant (crestal: p = 0.287; buccal: p = 0.534). Non-inferiority could be concluded for VCMX compared to SCTG for both ROI.
  
  
  CONCLUSIONS
  VCMX and SCTG can be used for soft tissue augmentation at implant sites resulting in an at least short-term increase in volume.
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Zeltner
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Jung
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Christoph H F
authors.initials: CH
authors.lastname: Hämmerle
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Hüsler
authors.affiliation: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Daniel S
authors.identifier: http://orcid.org/0000-0002-1764-7447
authors.initials: DS
authors.lastname: Thoma
mesh_terms: D000368:Aged; D003094:Collagen; D003238:Connective Tissue / Q000637:transplantation*; D015921:Dental Implants; D005260:Female; D005881:Gingiva / Q000033:anatomy & histology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D013997:Time Factors
chemical_list: D015921:Dental Implants; D003094:Collagen
keywords: collagen-based matrix; dental implant; soft tissue augmentation; soft tissue volume; subepithelial connective tissue graft