title: Improvement of microcirculation and wound healing in vertical ridge augmentation after pre-treatment with self-inflating soft tissue expanders - a randomized study in dogs.
abstract: OBJECTIVE
  We investigated the effect of soft tissue expansion (STE) on vertical ridge augmentation with regard to the incidence of wound dehiscences and the impairment of microcirculation in dogs, and the applicability of laser Doppler flowmetry (LDF) to explore the relation between microcirculation and wound healing.
  
  
  METHODS
  Bone defects were created on both mandibular sides in ten beagle dogs by extraction of premolars and removal of bone. Six weeks later, self-filling tissue expanders were implanted in randomly assigned test sites. After 5 weeks of expansion, vertical augmentation was carried out in test and control sites using calvarial onlay grafts side by side with granular biphasic calcium phosphate covered with a resorbable polyethylene glycol membrane. Microcirculation was evaluated with laser Doppler flowmetry (LDF). The incidence of wound dehiscences was evaluated after 2 weeks. The validity of LDF to predict dehiscences was evaluated by construction of receiver operating characteristic (ROC) curves.
  
  
  RESULTS
  After augmentation, test sites showed significantly better perfusion than control sites without preceding STE (P = 0.012). Three days after surgery, perfusion was still significantly decreased in control sites (P = 0.005), while microcirculation in test sites had returned to pre-surgical levels. After 2 weeks, healing in test sites was good, whereas eight dehiscences were found in control sites (P = 0.002). ROC curves showed that microcirculation levels immediately after augmentation surgery significantly predicted subsequent wound dehiscences (AUC = 0.799, CI 0.642-0.955, P = 0.006).
  
  
  CONCLUSIONS
  Laser Doppler flowmetry is suitable for evaluation of soft tissue microcirculation after ridge augmentation. STE reduced the impairment of microcirculation caused by vertical ridge augmentation and decreased the incidence of wound dehiscences in the investigated animal model.
authors.affiliation: Department of Periodontology, University of Witten/Herdecke, Witten, Germany.
authors.forename: Dogan
authors.initials: D
authors.lastname: Kaner
authors.forename: Han
authors.initials: H
authors.lastname: Zhao
authors.forename: Hendrik
authors.initials: H
authors.lastname: Terheyden
authors.forename: Anton
authors.initials: A
authors.lastname: Friedmann
mesh_terms: D000539:Alveolar Process / Q000098:blood supply* / Q000601:surgery; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects; D018786:Bone Substitutes / Q000494:pharmacology; D016025:Bone Transplantation; D003758:Dental Implantation, Endosseous; D004285:Dogs; D016557:Guided Tissue Regeneration, Periodontal / Q000379:methods*; D006882:Hydroxyapatites / Q000627:therapeutic use; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008833:Microcirculation / Q000502:physiology*; D013529:Surgical Wound Dehiscence / Q000601:surgery; D015626:Tissue Expansion / Q000379:methods*; D015625:Tissue Expansion Devices; D014945:Wound Healing / Q000502:physiology*
chemical_list: D018786:Bone Substitutes; D006882:Hydroxyapatites; C074950:hydroxyapatite-beta tricalcium phosphate
keywords: Laser Doppler flowmetry; bone augmentation; microcirculation; soft tissue expansion