title: Volume changes of maxillary sinus augmentations over time: a systematic review.
abstract: OBJECTIVE
  The objective of this study was to systematically review the available literature on three-dimensional time-dependent graft volume changes after sinus augmentation (SA) with different biomaterials in humans.
  
  
  METHODS
  MEDLINE, EMBASE, and CENTRAL were searched for related literature. Controlled and uncontrolled studies reporting volume changes of more than 10 SAs after at least 6 months, assessed by computed tomography (CT) or cone beam CT (CBCT), were eligible for inclusion. The primary outcome of interest was time-dependent percentage change in augmentation volume.
  
  
  RESULTS
  Seven controlled and five uncontrolled studies (n = 234 SAs) with a high risk of bias were included and reported on a range of graft materials. Autogenous bone (AB) was used in the particulate or block form. Bone substitutes (BS) were used either alone or in combination with other materials as composite grafts (CG). All studies reported reductions in augmentation volumes over time (AVR), generally after short observation periods (range, 6 months to 6 years). Substantial AVRs (approximately 45% in 77 SAs) were reported for AB after 6 months and up to 2 years. AVRs for solely BS or CG were relatively lower (approximately 18% to 22% in 142 SAs) after a similar time period. All studies reported a wide range of volume reductions. No significant differences in AVR were observed between different graft materials. Because of insufficient long-term data, a reliable association between volume reduction and time could not be established.
  
  
  CONCLUSIONS
  Some loss of augmentation volume always occurs after SA during early healing times. In general, less AVR may be expected after SA with BS or CG compared to SA with AB. Augmentation volume loss does not seem to compromise implant placement or survival.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Shanbhag
authors.forename: Vivek
authors.initials: V
authors.lastname: Shanbhag
authors.forename: Andreas
authors.initials: A
authors.lastname: Stavropoulos
mesh_terms: D064591:Allografts; D064592:Autografts; D001672:Biocompatible Materials; D018786:Bone Substitutes / Q000627:therapeutic use*; D016025:Bone Transplantation / Q000379:methods*; D054893:Cone-Beam Computed Tomography; D018849:Controlled Clinical Trials as Topic; D006801:Humans; D008443:Maxillary Sinus / Q000473:pathology / Q000601:surgery*; D059546:Sinus Floor Augmentation / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D001672:Biocompatible Materials; D018786:Bone Substitutes