title: Alveolar ridge preservation techniques: a systematic review and meta-analysis of histological and histomorphometrical data.
abstract: OBJECTIVE
  The aim of this article was to systematically review histological and histomorphometrical data from literature that provide information regarding the effect of alveolar ridge preservation procedures on healing after tooth extraction in humans.
  
  
  METHODS
  The MEDLINE-PubMed and the Cochrane CENTRAL databases were searched up to September 2012; 38 papers were selected from 646 founded. A meta-analysis was performed regarding the variations in the mean percentage of Bone, Connective Tissue and Residual Graft Material between three different types of Procedures.
  
  
  RESULTS
  The highest value regarding bone percentages is produced at 3 months by Procedures with Allografts (54.4%), while the lowest is obtained, at 5 months, by those using Xenografts (23.6%). Referring to connective tissue, the highest and lowest values are shown at 7 months, with Allografts (67%) and Alloplasts (27.1%), respectively. Regarding residual graft material, the lowest rates are displayed by Procedures with Allografts (12.4-21.11%), while those using Xenografts and Alloplasts showed the best results at 7 months (37.14 and 37.23%). No statistical difference was found.
  
  
  CONCLUSIONS
  With the limitations due to the features of the selected papers, no major histological and histomorphometrical differences arose among different procedures or when compared to spontaneous healing. Thus, it might be argued that in preserved sites it is unnecessary to wait over 3 to 4 months prior to implant insertion.
authors.affiliation: Private Practice, Rome, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: De Risi
authors.affiliation: Department of Dentistry, University "Tor Vergata", Rome, Italy.|Department of Periodontology, Tuscany Dental School, University of Siena-Florence, Siena, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Clementini
authors.affiliation: Department of Periodontology, Catholic University Sacred Heart, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Vittorini
authors.affiliation: Hygiene Unit, Department of Public Health and Infectious Diseases, Pharmacy and Medicine Faculty, Sapienza University of Rome, Rome, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Mannocci
authors.affiliation: Department of Periodontology, Tuscany Dental School, University of Siena-Florence, Siena, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: De Sanctis
mesh_terms: D016301:Alveolar Bone Loss / Q000473:pathology* / Q000517:prevention & control*; D000540:Alveolar Ridge Augmentation / Q000379:methods*; D016025:Bone Transplantation / Q000379:methods*; D003758:Dental Implantation, Endosseous; D006801:Humans; D014081:Tooth Extraction; D014945:Wound Healing / Q000502:physiology*
keywords: alveolar ridge preservation; bone grafts; histology; histomorphometry; membrane; socket preservation