title: Cranial base characteristics in anteroposterior malocclusions: A meta-analysis.
abstract: OBJECTIVE
  To investigate cranial base characteristics in malocclusions with sagittal discrepancies.
  
  
  METHODS
  An electronic search was performed in PubMed, Embase, Web of Science, and the Cochrane Library. A fixed- or random-effect model was applied to calculate weighted mean difference with 95% confidence intervals (CIs) according to statistical heterogeneity. Outcome measures were anterior, posterior, and total cranial base length and cranial base angle. Sensitivity analysis and publication bias were conducted.
  
  
  RESULTS
  Twenty studies that together included 1121 Class I, 1051 Class II, and 730 Class III cases qualified for the final analysis. Class III malocclusion demonstrated significantly reduced anterior (95% CI: -1.74, -0.53; P < .001 vs Class I; 95% CI: -3.30, -2.09; P < .001 vs Class II) and total cranial base length (95% CI: -3.33, -1.36; P < .001 vs Class I; 95% CI: -7.38, -4.05; P < .001 vs Class II). Further, Class II patients showed significantly greater anterior and total cranial base length than did Class I patients (95% CI: 0.51, 1.87; P < .001 for SN; 95% CI: 2.20, 3.30; P < .001 for NBa). Cranial base angle was significantly smaller in Class III than in Class I (95% CI: -3.14, -0.93; P < .001 for NSBa; 95% CI: -2.73, -0.68; P  =  .001 for NSAr) and Class II malocclusions (95% CI: -5.73, -1.06; P  =  .004 for NSBa; 95% CI: -6.11, -1.92; P < .001 for NSAr) and greater in Class II than in Class I malocclusions (95% CI: 1.38, 2.38; P < .001 for NSBa).
  
  
  CONCLUSIONS
  This meta-analysis showed that anterior and total cranial base length and cranial base angle were significantly smaller in Class III malocclusion than in Class I and Class II malocclusions, and that they were greater in Class II subjects compared to controls.
authors.affiliation: a   MD Student, Department of Orthodontics, School of Stomatology, Nanjing Medical University, Nanjing, China; Attending Physician, Department of Stomatology, Nanjing Children's Hospital, Affiliated with Nanjing Medical University, Nanjing, China.
authors.forename: Aixiu
authors.initials: A
authors.lastname: Gong
authors.affiliation: b   Chief Physician, Department of Stomatology, Nanjing Children's Hospital, Affiliated with Nanjing Medical University, Nanjing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: c   Associate Chief Physician, Department of Orthodontics, School of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: Zhendong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: d   Attending Physician, Department of Orthodontics, School of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: c   Associate Chief Physician, Department of Orthodontics, School of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Hu
authors.affiliation: c   Associate Chief Physician, Department of Orthodontics, School of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Li
authors.affiliation: e   Professor, State Key Laboratory of Reproductive Medicine, Center for Bone and Stem Cells, Department of Anatomy, Histology, and Embryology, Nanjing Medical University, Nanjing, China.
authors.forename: Dengshun
authors.initials: D
authors.lastname: Miao
authors.affiliation: f   Professor and Dean, Department of Orthodontics, School of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
mesh_terms: D002508:Cephalometry; D006801:Humans; D008310:Malocclusion; D008311:Malocclusion, Angle Class I; D008312:Malocclusion, Angle Class II; D008313:Malocclusion, Angle Class III; D019291:Skull Base / Q000033:anatomy & histology*
keywords: Cranial base; Malocclusion; Meta-analysis