title: Schneiderian Membrane Thickness and Clinical Implications for Sinus Augmentation: A Systematic Review and Meta-Regression Analyses.
abstract: Schneiderian membrane thickness (SMT) has been regarded as a key factor for influencing membrane perforation, which may jeopardize the final clinical outcome of sinus augmentation. Hence, this systematic review aims at studying the mean SMT and further investigating patient-related factors that may affect SMT. As a secondary goal, the association between SMT and membrane perforation rate was studied.
  
  
  
  Three independent reviewers in several databases, including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register databases, conducted electronic and manual literature searches. This review was written and conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and MECIR (Methodological Expectations of Cochrane Intervention Reviews) guidelines. Quantitative assessment was performed for articles that met the inclusion criteria to investigate the mean SMT, its contributing factors, and the influence on membrane damage and surgical complications.
  
  
  
  Thirty-one studies that reported maxillary SMT were considered for qualitative analysis. Nineteen were further meta-analyzed. Overall mean ± SE SMT was 1.17 ± 0.1 mm (95% confidence interval [CI] = 0.89 to 1.44). Although mean SMT for the three-dimensional radiography (3DR) group was 1.33 mm (95% CI = 1.06 to 1.60), for the histology group, it was 0.48 mm (95% CI = 0.12 to 1.1). Random-effects model showed that, although there is a trend for thicker SMT as determined using 3DR compared with histologic analysis, such difference did not reach statistical significance (P = 0.15). Also, regression analyses demonstrated that the variables periodontitis (P = 0.13) and smoking (P = 0.11) showed thicker SMT. Inconclusive data were obtained when correlating SMT and perforation rate, although it seems that thicker SMT might be more prone to perforation (P = 0.14).
  
  
  
  SMT is, on average, 1 mm in patients seeking sinus augmentation. Three-dimensional technologies overestimate approximately 2.5 times SMT when compared with histologic analysis. Periodontitis and smoking may result in thickening of the sinus membrane. However, current data were inconclusive to link SMT to the rate of membrane damage.
authors.affiliation: Department of Periodontics and Oral Medicine, University of Michigan, Ann Arbor, MI.
authors.forename: Alberto
authors.initials: A
authors.lastname: Monje
authors.affiliation: Department of Oral Implantology, Cayetano Heredia Peruvian University, Lima, Perú.
authors.forename: Karla Tatiana
authors.initials: KT
authors.lastname: Diaz
authors.affiliation: Department of Periodontology and Implant Dentistry, Cayetano Heredia Peruvian University.
authors.forename: Luisiana
authors.initials: L
authors.lastname: Aranda
authors.affiliation: Department of Periodontics and Oral Medicine, University of Michigan, Ann Arbor, MI.
authors.forename: Angel
authors.initials: A
authors.lastname: Insua
authors.affiliation: Department of Mathematics, University of Extremadura, Badajoz, Spain.
authors.forename: Agustin
authors.initials: A
authors.lastname: Garcia-Nogales
authors.affiliation: Department of Periodontics and Oral Medicine, University of Michigan, Ann Arbor, MI.
authors.forename: Hom-Lay
authors.initials: HL
authors.lastname: Wang
mesh_terms: D016301:Alveolar Bone Loss / Q000628:therapy*; D001861:Bone Regeneration; D016025:Bone Transplantation; D017267:Dental Prosthesis Design; D006801:Humans; D008437:Maxilla; D008443:Maxillary Sinus; D009297:Nasal Mucosa; D012044:Regression Analysis
keywords: Bone regeneration; dental implants; dentistry, evidence-based; maxillary sinus; oral surgical procedures; sinus floor augmentation.