title: Guided bone regeneration and abutment connection augment the buccal soft tissue contour: 3-year results of a prospective comparative clinical study.
abstract: OBJECTIVE
  To test whether implant placement with simultaneous guided bone regeneration (GBR) differs from implant placement without GBR regarding the change in marginal mucosal contour.
  
  
  METHODS
  In 28 patients, single implants were placed >4 months after tooth extraction. Eighteen implants were completely surrounded by native bone, and no bone augmentation was performed. At 10 implant sites, bone defects and thin bone plates were grafted with deproteinized bovine-derived bone mineral and covered with collagen membrane. Impressions were taken prior to implant placement (baseline), at 3 months before abutment connection, at 6 months immediately after crown insertion, at 1 year, and at 3 years. Models were optically scanned and 3D images were superimposed for the evaluation of mucosal contour changes at the mid-buccal aspect. The nonparametric Mann-Whitney U-test was applied to detect differences.
  
  
  RESULTS
  From baseline to 6 months, horizontal contour change at the level 1 and 2 mm apical to the mucosal margin measured 0.65 ± 0.74 mm and 0.55 ± 0.56 mm at sites without GBR, and 1.92 ± 0.87 mm and 1.76 ± 0.70 mm at sites with GBR (P < 0.05). In the period from baseline to 1 year, the corresponding values amounted to 0.81 ± 0.67 mm and 0.60 ± 0.55 mm in the group without GBR, and to 1.81 ± 0.86 mm and 1.37 ± 0.62 mm in the group with GBR (P < 0.05). From baseline to 6 months, mucosal margin moved 0.16 ± 0.49 mm in the coronal direction in the group without GBR and 0.82 ± 0.65 mm in the group with GBR (P < 0.05). In the period from baseline to 1 year, vertical change of mucosal margin amounted to 0.64 ± 0.54 mm in the group without GBR and to 1.17 ± 0.53 mm in the GBR group (P < 0.05). From 1 to 3 years, the mucosal contours remained stable.
  
  
  CONCLUSIONS
  Implant placement with simultaneous GBR resulted in more gain of buccal soft tissue contour in comparison with implant placement without GBR. Abutment connection increased the contour of the marginal mucosa at the augmented and the nonaugmented sites. GBR procedure contributed more to the contour gain than did the abutment connection. The augmented and the nonaugmented ridges exhibited stable peri-implant mucosal contour over a 3-year period.
authors: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors: Goran I
authors: GI
authors: Benic
authors: Department of Prosthodontics, Hospital of Stomatology, Peking University, Beijing, China.
authors: Yanjun
authors: Y
authors: Ge
authors: Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA, USA.
authors: German O
authors: GO
authors: Gallucci
authors: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors: Ronald E
authors: RE
authors: Jung
authors: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors: David
authors: D
authors: Schneider
authors: Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Zurich, Switzerland.
authors: Christoph H F
authors: CH
authors: Hämmerle
mesh_terms: D016301:Alveolar Bone Loss / Q000473:pathology*; D001861:Bone Regeneration; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D005260:Female; D005881:Gingiva / Q000473:pathology*; D016557:Guided Tissue Regeneration, Periodontal; D006801:Humans; D008297:Male; D008875:Middle Aged; D003765:Models, Dental; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: GBR; abutment connection; bone; bone substitute; clinical; contour; dental implant; guided bone regeneration; human; mucosa; optical; regeneration; scan; soft tissue; volume