title: What is the best position for palatal implants? A CBCT study on bone volume in the growing maxilla.
abstract: OBJECTIVE
  The objectives of the present study are the following: (a) to investigate limitations (bone height, proximity to nasopalatine nerve and roots) in juvenile patients, (b) to review the recommended site for surgical insertion (level of the maxillary first premolars), and (c) to reassess the rationale behind the manufacturer's age limitation (12 years).
  
  
  METHODS
  Cone beam CT images of 100 patients aged 10 to 20 years were analyzed. Vertical bone heights were measured in the median plane as well as 3- and 6-mm paramedian along the prospective axis of insertion, at the level of the first premolars (level 0), 3 mm anterior (level 1) and 3 mm posterior (level 2). The Mann-Whitney U test was used to compare bone heights between gender groups.
  
  
  RESULTS
  The risk of damage to the nasopalatine nerve is highest in the median region on level 1 (46 %). The risk was lowest in the midsagittal region on level 0 (recommended insertion site; 3 %) and level 2 (0 %), as well as paramedian on levels 0 and 2. The risk of damaging roots was irrelevant for median insertion at all levels; the only critical region was 6-mm paramedian on level 1.
  
  
  CONCLUSIONS
  The recommendation of surgical insertion at the level of the maxillary first premolars is still justified, but a slightly more posterior implant position might improve safety. We found no relevant growth-related changes in the vertical bone heights in the median palatal area. Thus, our data do not support the strict 12-year age restriction for palatal implants.
authors.affiliation: Department of Oral and Maxillofacial-Plastic Surgery, Ruhr University of Bochum, Bochum, Germany.
authors.forename: Darafsch
authors.initials: D
authors.lastname: Kawa
authors.affiliation: Department of Oral and Maxillofacial-Plastic Surgery, Ruhr University of Bochum, Bochum, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kunkel
authors.affiliation: Department of Diagnostic and Interventional Radiology, Neuroradiology and Nuclear Medicine, Ruhr University of Bochum, Bochum, Germany.
authors.forename: Lothar
authors.initials: L
authors.lastname: Heuser
authors.affiliation: Department of Orthodontics, University Medical Center Freiburg, Hugstetter. Str, 55 79106, Freiburg, Germany. britta.jung@uniklinik-freiburg.de.
authors.forename: Britta A
authors.initials: BA
authors.lastname: Jung
mesh_terms: D000293:Adolescent; D002648:Child; D054893:Cone-Beam Computed Tomography; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging* / Q000601:surgery*; D008445:Maxillofacial Development; D009059:Mouth Diseases / Q000000981:diagnostic imaging* / Q000601:surgery*; D021362:Palate, Hard / Q000000981:diagnostic imaging* / Q000601:surgery*; D019736:Prostheses and Implants; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: Age restriction for palatal implants; Anatomic limitations; Growth-related changes in adolescents