title: Pre-augmentation soft tissue expansion improves scaffold-based vertical bone regeneration - a randomized study in dogs.
abstract: OBJECTIVE
  Soft tissue (ST) dehiscence with graft exposure is a frequent complication of vertical augmentation. Flap dehiscence is caused by failure to achieve tension-free primary wound closure and by the impairment of flap microcirculation due to surgical trauma. Soft tissue expansion (STE) increases ST quality and quantity prior to reconstructive surgery. We hypothesized that flap preconditioning using STE would reduce the incidence of ST complications after bone augmentation and that optimized ST healing would improve the outcome of bone regeneration.
  
  
  METHODS
  Self-filling tissue expanders were implanted in mandibular bone defects in ten beagle dogs. After expansion, alloplastic scaffolds were placed for vertical bone augmentation in STE sites and in control sites without STE pre-treatment. ST flap microcirculation was analysed using laser Doppler flowmetry. The incidence of graft exposures was evaluated after 2 weeks. Bone formation was assessed after 2 months, using histomorphometry and immunohistochemistry.
  
  
  RESULTS
  Test sites showed significantly less impairment of perfusion and faster recovery of microcirculation after bone augmentation. Furthermore, no flap dehiscences occurred in STE sites. Bone regeneration was found in both groups; however, significantly greater formation of new bone was detected in test sites with preceding STE.
  
  
  CONCLUSIONS
  Preconditioning using STE improved ST healing and bone formation after vertical augmentation. The combination of STE and the subsequent placement of alloplastic scaffolds may facilitate the reconstruction of severe bone defects.
authors.affiliation: Department of Periodontology, Witten/Herdecke University, Witten, Germany.
authors.forename: Doğan
authors.initials: D
authors.lastname: Kaner
authors.affiliation: Department of Periodontology, Witten/Herdecke University, Witten, Germany.|Multi-disciplinary Treatment Center, Beijing Stomatological Hospital, Capital Medical University, Beijing, China.
authors.forename: Han
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Oral Biology and Materials Science, Witten/Herdecke University, Witten, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Arnold
authors.affiliation: Department of Maxillofacial Surgery, Rotes-Kreuz-Krankenhaus Kassel, Kassel, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Terheyden
authors.affiliation: Department of Periodontology, Witten/Herdecke University, Witten, Germany.
authors.forename: Anton
authors.initials: A
authors.lastname: Friedmann
mesh_terms: D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D001861:Bone Regeneration; D004285:Dogs; D008297:Male; D023421:Models, Animal; D011897:Random Allocation; D015626:Tissue Expansion; D015625:Tissue Expansion Devices
keywords: animal experiments; biomaterials; bone regeneration; guided tissue regeneration; surgical techniques; wound healing