title: The effectiveness of different mandibular advancement amounts in OSA patients: a systematic review and meta-regression analysis.
abstract: OBJECTIVE
  The therapy with mandibular advancement devices (MADs) represents a treatment option for patients with obstructive sleep apnea (OSA). The literature does not provide evidence regarding the most effective mandibular advancement; therefore, the aim of this systematic review with meta-regression was to investigate the effectiveness of different mandibular advancement amounts in reducing apnea-hypopnea index (AHI) in OSA patients.
  
  
  METHODS
  An electronic search was performed in MEDLINE, Cochrane Database, Google Scholar Beta, ISI Web of Knowledge, Scopus, and LILACS to select randomized controlled trials (RCTs) investigating the efficacy of MADs in reducing AHI in adult OSA patients. Inclusion criteria were the diagnosis of OSA and success evaluation performed with a polysomnography, follow-up of maximum 12 months, and protrusion amount reported as a percentage of the maximum mandibular advancement. The quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. The success rate of each study was computed: [(mean AHI at baseline-mean AHI after treatment)/mean AHI at baseline].
  
  
  RESULTS
  Thirteen RCTs performing advancements from 50 to 89 % of maximum mandibular protrusion were included. The meta-regression analysis showed that advancement amounts higher than 50 % do not significantly influence the success rate (Q = 0.373, p = 0.541). According to the GRADE score system, the quality of evidence resulted to be moderate.
  
  
  CONCLUSIONS
  The AHI improvement resulted to be not proportional to the mandibular advancement increase. It is plausible that the success of the therapy is influenced by a combination of variables that need closer study.
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Oral Sciences, Section of Orthodontics, University of Naples "Federico II", via Pansini, 5, 80131, Naples, Italy. maria.bartolucci@studio.unibo.it.
authors.forename: Maria Lavinia
authors.initials: ML
authors.lastname: Bartolucci
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Oral Sciences, Section of Orthodontics, University of Naples "Federico II", via Pansini, 5, 80131, Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Bortolotti
authors.affiliation: Department of Biomedical Sciences, Section of Orthodontics, University of Bologna, via san Vitale, 59, 40125, Bologna, Italy.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Raffaelli
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Oral Sciences, Section of Orthodontics, University of Naples "Federico II", via Pansini, 5, 80131, Naples, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: D'Antò
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Oral Sciences, Section of Orthodontics, University of Naples "Federico II", via Pansini, 5, 80131, Naples, Italy.
authors.forename: Ambra
authors.initials: A
authors.lastname: Michelotti
authors.affiliation: Department of Biomedical Sciences, Section of Orthodontics, University of Bologna, via san Vitale, 59, 40125, Bologna, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Alessandri Bonetti
mesh_terms: D006801:Humans; D019186:Mandibular Advancement / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000628:therapy*; D016896:Treatment Outcome
keywords: Mandibular advancement device; Obstructive sleep apnea; Sleep disordered breathing; Sleep disorders; Temporomandibular disorders