title: Crestal bone loss around submerged and nonsubmerged dental implants: A systematic review.
abstract: BACKGROUND
  To my knowledge, there is no systematic review of crestal bone loss (CBL) around submerged and nonsubmerged dental implants.
  
  
  OBJECTIVE
  The purpose of this review was to systematically assess CBL around submerged and nonsubmerged dental implants.
  
  
  METHODS
  The addressed focused question was, "Does crestal and subcrestal placement of dental implants influence crestal bone levels?" Databases were searched from 1986 through October 2015 using different combinations of the following keywords: crestal, sub-crestal, bone loss, dental implant, submerged, and nonsubmerged. Reference lists of potentially relevant original and review articles were hand-searched to identify any further studies. Letters to the editor, case reports, commentaries, studies on platform-switched implants, and studies published in languages other than English were excluded.
  
  
  RESULTS
  In total, 13 studies (6 human and 7 animal), which were performed at universities, were included. In the human studies, the number of participants ranged from 8 to 84 individuals. The follow-up period ranged from 1 to 5 years. CBL at the test sites ranged from 0.17 mm to 0.9 mm and at control sites from 0.02 mm to 1.4 mm. Five human studies reported no significant difference in CBL around implants placed at the test and control sites. All animal studies were performed in dogs with a mean age ranging from 1 to approximately 2 years. The follow-up period ranged from 2 to 6 months. Four animal studies reported no significant difference in CBL around submerged and nonsubmerged implants.
  
  
  CONCLUSIONS
  No significant difference in CBL was found around submerged and nonsubmerged dental implants.
authors.affiliation: Associate Professor and Consultant, Department of Prosthetic Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia. Electronic address: dramri@yahoo.com.
authors.forename: Mohammad D
authors.initials: MD
authors.lastname: Al Amri
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology*; D000818:Animals; D003758:Dental Implantation, Endosseous / Q000009:adverse effects; D015921:Dental Implants / Q000009:adverse effects*; D019232:Dental Restoration Failure; D006801:Humans
chemical_list: D015921:Dental Implants