title: Incorporation and Remodeling of Bone Block Allografts in the Maxillary Reconstruction: A Randomized Clinical Trial.
abstract: BACKGROUND
  Severe alveolar atrophy often presents a challenge for the implant surgery. The significant lack of bone in the alveolar ridges may compromise the final restorations both from the aesthetic and functional standpoints.
  
  
  OBJECTIVE
  To evaluate the behavior of bone block allografts for the maxillary augmentation and to investigate its incorporation, remodeling, and implant survival rates in two different healing time points.
  
  
  METHODS
  Sixty-six consecutive patients (52 female/14 male, mean age: 57.95 ± 9.06 years old), presenting 113 atrophic alveolar ridges underwent maxillary augmentation with fresh-frozen allogeneic bone blocks from tibia. Patients were randomly assigned in two groups: Group 1-patients who would wait 4 months for implant placement after grafting, and Group 2-patients who would wait 6 months. Events of infection, suture dehiscence or mucosal perforation were recorded. Cone-beam computed tomography scans were compared volumetrically between the time of the grafting surgery and reentry procedure after incorporation. Biopsies were collected and subjected to histological, histomorphometric and immunehistochemical analysis.
  
  
  RESULTS
  A total of 305 implants were placed in the reconstructed sites. The mean resorption rate in Group 1 (13.98% ± 5.59) was significantly lower than Group 2 (31.52% ± 6.31). The amount of calcified tissue, newly formed bone and remaining graft particles demonstrated no difference between groups. The samples showed evident immunolabeling for the podoplanin protein in both groups. The implants cumulative survival rate was 94.76%.
  
  
  CONCLUSIONS
  The findings of the present study indicate that there is a significant difference regarding the resorption of the grafts when waiting 4 or 6 months before placing the implants, even though no difference was found in the histological, histomorphometric, and immunohistochemical features. Both 4-month and 6-months healing times are suitable for the implant placement.
authors.affiliation: Postdoctoral researcher, Department of Periodontology, State University of Rio de Janeiro, RJ, Rio de Janeiro, Brazil.
authors.forename: Daniel
authors.identifier: http://orcid.org/0000-0003-4959-528X
authors.initials: D
authors.lastname: Deluiz
authors.affiliation: Professor, Department of Implantology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Luciano
authors.initials: L
authors.lastname: Santos Oliveira
authors.affiliation: Professor, Department of Stomatology, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: Fábio
authors.initials: F
authors.lastname: Ramôa Pires
authors.affiliation: Investigator, Geriatric Research, Education and Clinical Center - Bruce W. Carter Veterans Affairs Medical Center, Miami, FL, USA.
authors.forename: Teresita
authors.initials: T
authors.lastname: Reiner
authors.affiliation: Professor, Department of Endodontics, Estácio de Sá University, Rio de Janeiro, RJ, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Armada
authors.affiliation: Professor, Department of Statistics, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
authors.forename: Marcus A
authors.initials: MA
authors.lastname: Nunes
authors.affiliation: Professor, Department of Periodontology, State University of Rio de Janeiro, RJ, Rio de Janeiro, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Muniz Barretto Tinoco
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000473:pathology / Q000601:surgery*; D016723:Bone Remodeling / Q000502:physiology*; D001862:Bone Resorption; D016025:Bone Transplantation / Q000379:methods*; D054893:Cone-Beam Computed Tomography; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019094:Dental Prosthesis, Implant-Supported / Q000379:methods; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008437:Maxilla / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008875:Middle Aged; D009066:Mouth, Edentulous / Q000503:physiopathology / Q000601:surgery*; D016348:Osseointegration / Q000502:physiology*; D010011:Osteocytes / Q000473:pathology; D059546:Sinus Floor Augmentation / Q000379:methods*; D013997:Time Factors
keywords: alveolar ridge reconstruction; bone allograft, bone augmentation; bone grafting; edentulous atrophic maxilla; histological analysis; implant survival; randomized controlled trial