title: A principal components analysis: how pneumatization and edentulism contribute to maxillary atrophy.
abstract: OBJECTIVE
  The aim of this retrospective cohort study was to investigate the role of sinus pneumatization and residual ridge resorption in maxillary bone loss in 400 computed tomography (CT) scans.
  
  
  METHODS
  In 200 dentate and 200 edentulous patients, both sinuses were analysed using CT scans. The image analysis sequence consisted of manual placement of 24 reference points, followed by automated segmentation and final manual refinement. Finally, a principal components analysis was performed.
  
  
  RESULTS
  A total of 788 sinuses were included into the analysis. The edentulous group (98 female: 67.77 ± 11.28 years, 99 male: 65.22 ± 9.87) was significantly older than the group with teeth (99 female: 46.89 ± 16.77 years, 96 male: 49.74 ± 16.2). Female and male patients did not differ regarding age. The alveolar height differed significantly between the groups (edentulous: 7.1 ± 4.3 mm, with teeth: 9.7 ± 4.1 mm), but not between gender (female: 8.3 ± 4.4 mm, male: 8.5 ± 4.4 mm). Principal components analysis was able to explain 90% of the variation in sinus morphology.
  
  
  CONCLUSIONS
  Prolonged edentulism in the maxillary molar region leads to centripetal and to minor degrees centrifugal ridge resorption. Minor pneumatization occurs in the sinus walls, but the sinus depth underlies the anatomical variation independent of dentition.
authors.affiliation: University Clinic for Cranio- and Maxillofacial Surgery, Medical University Vienna, Vienna, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Wagner
authors.affiliation: University Clinic of Dentistry, Medical University Vienna, Vienna, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Dvorak
authors.affiliation: University Clinic for Radiology, Medical University Vienna, Vienna, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Nemec
authors.affiliation: Centre for Pathophysiology, Infectiology and Immunology, Medical University Vienna, Vienna, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Pietschmann
authors.affiliation: Centre for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Figl
authors.affiliation: University Clinic for Cranio- and Maxillofacial Surgery, Medical University Vienna, Vienna, Austria.
authors.forename: R
authors.initials: R
authors.lastname: Seemann
mesh_terms: D000368:Aged; D016301:Alveolar Bone Loss / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000473:pathology*; D008439:Maxillary Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D008443:Maxillary Sinus / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D009066:Mouth, Edentulous / Q000150:complications* / Q000473:pathology; D025341:Principal Component Analysis; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
keywords: alveolar bone atrophy; alveolar ridge augmentation; dental implants; morphology; preprosthetic oral surgical procedure; principal components analysis