title: Dental implants placed in grafted maxillary sinuses: a retrospective analysis of clinical outcome according to the initial clinical situation and a proposal of defect classification.
abstract: OBJECTIVE
  To present a classification of maxillary defects necessitating sinus floor elevation procedures (SFEPs) with two objectives: (a) to propose a standardization of surgical procedures according to initial type of atrophy and (b) to allow the evaluation of the success/survival rates of implants placed in the grafted areas according to the initial situation.
  
  
  METHODS
  Nine-hundred and fifty-two consecutive SFEP were performed on 692 patients. Initial defects were classified according to a new classification, which considered not only residual bone height below the sinus but also the width of the alveolar crest and horizontal/vertical intermaxillary relationship. Results were evaluated according to the different classes. The sinuses were grafted with autogenous bone taken from intra-oral or extra-oral sites: 579 SFEP were associated with vertical and/or horizontal onlay grafts to correct concomitant alveolar ridge deficits. A total of 2037 implants were inserted into the grafted sinuses either immediately or 4-6 months later. Three to 6 months afterwards, implants were loaded. The mean follow-up was 59 months (range: 12-144 months).
  
  
  RESULTS
  The success rate of the reconstructive procedures varied between 93.2% and 100%, according to class of atrophy; the overall survival and success rates of implants were 95.8% and 92.5%, respectively, whereas the survival and success rates according to class of atrophy varied between 90% and 97.6%, and between 85.4% and 95.5%, respectively. Lower success rates were found in classes presenting with more severe atrophy.
  
  
  CONCLUSIONS
  The results obtained demonstrated that sinus floor elevation, alone or in association with reconstructive procedures with autogenous bone grafts, is a reliable procedure to allow implant placement in atrophic edentulous maxillae, irrespective of the initial clinical situation. However, it must be underlined that the success rates of reconstructive procedures and implants differ according to class of atrophy, showing lower success rates in classes presenting with more severe atrophy.
authors.affiliation: Unit of Oral Surgery, Department of Medicine, Surgery, and Dentistry, San Paolo Hospital, University of Milan, Milan, Italy. matteo.chiapasco@unimi.it
authors.forename: Matteo
authors.initials: M
authors.lastname: Chiapasco
authors.forename: Marco
authors.initials: M
authors.lastname: Zaniboni
authors.forename: Lia
authors.initials: L
authors.lastname: Rimondini
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000145:classification*; D015519:Bone Density; D016025:Bone Transplantation; D003758:Dental Implantation, Endosseous; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation; D015993:Life Tables; D008297:Male; D008439:Maxillary Diseases / Q000145:classification*; D008443:Maxillary Sinus / Q000601:surgery*; D008875:Middle Aged; D016017:Odds Ratio; D013516:Oral Surgical Procedures, Preprosthetic / Q000379:methods*; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016896:Treatment Outcome