Maxillomandibular advancement is a safe procedure in patients with obstructive sleep apnoea. Results of a retrospective study.

Obstructive sleep apnoea (OSA) is a syndrome with a high burden on public health. Maxillomandibular advancement (MMA) has proven to be a highly effective treatment option. This retrospective analysis evaluated the safety of maxillomandibular advancement with rotation in patients with OSA. A total of 63 patients with OSA were included in this study. Surgical treatment by maxillomandibular advancement was virtually planned based on preoperative cone beam computed tomography (CBCT). A 3D printed guide and a customised implant were used for surgical transfer. The safety of MMA was evaluated based on the necessity of postoperative intermediate care unit (IMCU) stay, duration of stay in hospital, and recording of medical complications. A total of 63.5% of the OSA patients treated by MMA (n = 40/63) were postoperatively transferred from the recovery room directly to the regular ward, while 36.5% of the patients (n = 23/63) stayed on IMCU for at least one night. On average, the length of hospitalisation was four days after surgery. One patient from the ward group and one patient from the IMCU group developed a major complication according to Clavian-Dindo classification grade IV. MMA is a safe surgical procedure. The necessity for postoperative monitoring in an IMCU setting should be based on an individual risk evaluation. However, since major complications can occur, MMA should be performed as an inpatient procedure in a hospital with available intensive medicine care. This study underlines the safety of MMA in OSA patients.

Central and mixed sleep apnea related to patients treated with maxillomandibular advancement for obstructive sleep apnea: A retrospective cohort study.

The aim of this study was to evaluate the clinical efficacy of maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) patients with a percentage of central and mixed apnea index in the total apnea-hypopnea index (CMAI%) ≧25%. Patients treated with MMA for OSA were retrospectively evaluated for baseline and postoperative patient data and polysomnographic results. The pre- and postoperative obstructive, central and mixed apnea parameters were compared. Of the included 78 patients, 21 patients (27%) presented with CMAI% ≧25% (median CMAI%, 49.1%; 35.9-63.8) prior to MMA. In 67% of these cases, MMA resulted in CMAI% <25 (median CMAI%, 6.1%; 2.1-8.9) and significantly improved the apnea-hypopnea index (AHI) (p < 0.001), the lowest oxyhemoglobin saturation (p < 0.001), central and mixed apnea index (p < 0.001), percentage of central and mixed apneas of total AHI (p = 0.004), central apnea index (p < 0.001), and mixed apnea index (p < 0.001). CMAI% ≧25% emerged in 25% of patients after MMA (median CMAI%, 49.1%; 35.9-63.8). Within the undeniable limitations of the study, it seems that the presence of CMAI% ≧25% should not be regarded as a contraindication for MMA in OSA patients.

Treatment of OSA by maxillomandibular advancement: Serious Complications and Failures / Traitement du SAOS par avancement maxillomandibulaire : complications graves et échecs

Aim: The focus of this report was to analyze patients who presented for second opinion due to complications and failure following maxillomandibular advancement (MMA)performed elsewhere. Methods: During a five-year period, 16 patients presented with complications and/or failure of MMA. The indication for treatment was obstructive sleep apnea (OSA). Analysis of treatment records including plane radiography and/or cone beam computed tomography (CBCT), progress photographs and clinical examination were performed. Results: Complete clinical and imaging records were available in all patients for analysis. Thirteen patients were surgical failures with advancement ranging from -4 to 5 mm. Five of the 13 patients had limited advancement at the initial surgery, and eight patients had hardware failure that required removal with resultant retrodisplacement of the mandible. Due to complications occurring in 11 patients, additional surgery ranging from two to six additional procedures after the initial operation was required. The complications included hardware failure (ten patients) that led to bone segment displacement (eight patients), non-union of the maxilla (two patients), non-union of the mandible (eight patients), chronic facial and/or joint pain (five patients), facial nerve injury (two patient), complete anesthesia of the lip/chin (five patients) and severe malocclusion (four patients). Conclusions: Although MMA is typically a predictable operation with excellent outcomes, failure of improvement and severe long-term sequelae from surgical complications are possible. Surgical precision with sufficient skeletal advancement for airway improvement and stable skeletal fixation is necessary to achieve a successful outcome.

Objectif: L'objectif de ce rapport était d'analyser les patients qui se sont présentés pour un deuxième avis, en raison de complications et d'un échec survenus après un avancement maxillo-mandibulaire (AMM) réalisé ailleurs. Méthodes: Au cours d'une période de cinq années, seize patients se sont présentés avec des complications et/ou un échec de leur AMM. L'indication du traitement était l'apnée obstructive du sommeil (AOS). Une analyse des dossiers de traitement, comprenant une radiographie 2D et/ou une tomographie à faisceau conique (CBCT), des photographies de l'évolution et un examen clinique, a été effectuée. Résultats: Des dossiers cliniques et d'imagerie complets étaient disponibles pour tous les patients aux fins d'analyse. Treize patients étaient des échecs chirurgicaux avec un avancement allant de -4 à 5 mm. Cinq des 13 patients avaient un avancement limité lors de la chirurgie initiale, et huit patients ont été confrontés à une défaillance du matériel qui en a nécessité la dépose avec pour conséquence un rétro-déplacement de la mandibule. En raison de complications survenues chez 11 patients, une chirurgie supplémentaire, allant de deux à six interventions additionnelles après l'opération initiale, a été nécessaire. Les complications comprenaient une défaillance du matériel (dix patients) qui a entraîné un déplacement du segment osseux (huit patients), une pseudarthrose du maxillaire (deux patients), une pseudarthrose de la mandibule (huit patients), une douleur faciale et/ou articulaire chronique (cinq patients), une lésion du nerf facial (deux patients), une anesthésie complète de la lèvre/menton (cinq patients) et une malocclusion grave (quatre patients). Conclusions: Bien que l'AMM soit généralement une opération prévisible avec d'excellents résultats, une absence d'amélioration et de graves séquelles à long terme dues à des complications chirurgicales sont possibles. La précision du geste chirurgical, associée à un avancement du squelette suffisant pour améliorer les voies respiratoires et une bonne stabilité de l'ostéosynthèse du squelette, sont nécessaires pour obtenir un résultat satisfaisant.

Condylar resorption following mandibular advancement or bimaxillary osteotomies: A systematic review of systematic reviews.

Several systematic reviews have been published on the effects of mandibular surgery on condylar remodeling without reaching a consensus. The purpose of this systematic review of systematic reviews was to assess the impact of mandibular advancement or bimaxillary surgeries on condylar resorption. A literature search, using several electronic databases, was carried out by two reviewers independently. Article preselection was based on titles and abstracts, and final article selection based on full-text analysis of preselected studies. After final study selection, the quality of studies was assessed using the AMSTAR 2 tool. A decision algorithm was subsequently established to choose the best body of evidence. From an initial yield of 1'848 articles, 23 systematic reviews were identified for further analysis, with ten studies being included in the final selection. Despite the generally low quality of the reviews, certain associations could be made: young patients, female patients, and those with a high mandibular plane angle are more prone to condylar resorption following mandibular advancement osteotomies, especially if anterior rotation of the mandible is performed during surgery. Patients undergoing bimaxillary surgery also appear to have a higher risk of developing condylar resorption. In conclusion, these results confirm the multi-factorial nature of condylar resorption, stressing the need for well-controlled prospective studies with long-term follow-up to clearly identify potential risk factors associated with orthognathic surgery.

Maxillomandibular Advancement for OSA: Serious Complications and Failures

Objective: The focus of this report was to analyze patients who presented for second opinion due to complications and failure following maxillomandibular advancement (MMA) performed elsewhere. Materials and Methods: During a five-year period, 16 patients presented with complications and/ or failure of MMA. The indication for treatment was obstructive sleep apnea (OSA). Analysis of treatment records including plane radiography and/or cone beam computed tomography (CBCT), progress photographs and clinical examination were performed. Results: Complete clinical and imaging records were available in all patients for analysis. Thirteen patients were surgical failures with advancement ranging from -4 to 5 mm. Five of the 13 patients had limited advancement at the initial surgery, and eight patients had hardware failure that required removal with resultant retrodisplacement of the mandible. Due to complications occurring in 11 patients, additional surgery ranging from two to six additional procedures after the initial operation was required. The complications included hardware failure (ten patients) that led to bone segment displacement (eight patients), non-union of the maxilla (two patients), non-union of the mandible (eight patients), chronic facial and/or joint pain (five patients), facial nerve injury (two patients), complete anesthesia of the lip/chin (five patients) and severe malocclusion (four patients). Conclusions: Although MMA is typically a predictable operation with excellent outcomes, failure of improvement and severe long-term sequelae from surgical complications are possible. Surgical precision with sufficient skeletal advancement for airway improvement and stable skeletal fixation is necessary to achieve a successful outcome.

Mandibular advancement device: Effectiveness and dental side effects. A real-life study.

Objective: To investigate the effectiveness and adverse events of mandibular advancement device (MAD) in patients with obstructive sleep apnea (OSA) and to identify predictive clinical parameters for therapy success.Methods: A retrospective analysis of 318 patients indicated for MAD therapy, observed in a large teaching hospital in the Netherlands.Results: Ninety-seven patients (65.5%) achieved therapy success. A significant decrease in AHI (apnea-hypopnea index) and OSA-related symptoms was observed. None of the analyzed OSA-characteristics proved to be a significant predictive parameter for therapy success. Side-effects were reported in 54.4% of the patients, with temporomandibular dysfunction (27.0%) being the most frequent. Seventy-four patients (23.3%) discontinued treatment due to side-effects or therapy failure.Conclusion: MAD proved to be effective in the treatment of OSA and can be a viable alternative to CPAP in patients with severe OSA. Side-effects were relatively common and led to termination of therapy in 1 out of 10 cases.

[Obstructive sleep apnea syndrome : CPAP or Mandibular Advancement Device?] / Syndrome d'apnées obstructives du sommeil : CPAP ou orthèse d'avancement mandibulaire ?

Obstructive sleep apnea syndrome (OSAS) is a respiratory disorder affecting up to 49 % and 23 % of middle to older aged men and women respectively. CPAP (continuous positive airway pressure) is the gold-standard treatment for severe apneas. In mild and moderate forms of OSAS, mandibular advancement devices (MAD) are equally a first line of treatment. Both CPAP and MAD have their advantages and side effects. Patient tolerance to these two therapies varies according to different patient-parameters. In order to guide physicians and patients in choosing between these two treatments, we present a description of both treatment modalities.

Le syndrome d'apnées obstructives du sommeil (SAOS) est un trouble respiratoire du sommeil qui affecte jusqu'à 49 % des hommes et 23 % des femmes d'âge moyen à avancé. La ventilation en pression positive continue (CPAP) est actuellement le traitement de choix pour les cas sévères. Dans les stades léger et modéré de SAOS, l'orthèse d'avancement mandibulaire (OAM) est également un traitement que l'on peut proposer en première intention. La CPAP comme l'OAM ont leurs avantages et leurs inconvénients. La tolérance pour ces deux thérapies varie d'un patient à l'autre. Afin de guider le praticien et le patient dans le choix de ces deux traitements, nous proposons une description des deux modalités thérapeutiques.

[Oral appliances for obstructive sleep apnoea: What can we expect?] / Orthèses d'avancée mandibulaire et syndrome d'apnées-hypopnées obstructives du sommeil : qu'en attendre ? Revue de la littérature, comparaison par design.

INTRODUCTION: Mandibular appliances are a treatment option for obstructive sleep apnea. There are many designs, but in the literature they tend to be grouped into a single entity without considering that efficiency, tolerance, compliance, or side effects are inherent in the design of each of them. A more detailed literature review is therefore warranted for the reader who wants to understand the relative effectiveness of each appliance. STATE OF KNOWLEDGE: We conducted a literature search using the "oral appliance" and "obstructive sleep apnea" criteria on Pubmed, Embase and Cochrane. This allowed us to compare outcome parameters by appliance class and to highlight the rare studies comparing different appliances. CONCLUSIONS: Mandibular appliances are not a homogeneous entity. Common use includes only appliances designed for propulsion (with rods and jacks) and retention. However, the few comparative studies available do not identify which are the most effective types or the types with an optimal efficacy/tolerance ratio. PERSPECTIVES: Further appliance comparison studies are needed to determine the most effective type or with an optimal efficacy/tolerance ratio.

Avoiding and Managing Oral Appliance Therapy Side Effects.

There is a serious need to consider all potential side effects thoughtfully before commencing individual treatment with oral appliance therapy. Although many of these side effects are self-limiting, easily corrected, or innocuous, others are difficult or impossible to correct and can affect the patient in serious ways. As this field evolves, new information is discovered, and new products are introduced at a rather rapid pace, continuing education and prudent practice are critical to ethical care in the practice of dental sleep medicine.

Mandibular advancement impairs swallowing ability more than head extension but less than mouth opening in the supine position.

Mandibular advancement in the supine position may influence swallowing during dental treatment under intravenous sedation. This study investigated the influence of mandibular advancement in the supine position on swallowing ability, compared with head extension and mouth opening. The water swallowing test was performed in 13 healthy, awake, supine, adult subjects under four head and mandibular positions. An electromyogram of the suprahyoid muscles was recorded; the duration and peak amplitude were examined. A greater volume of water remained in the mouth during mouth opening and mandibular advancement relative to the neutral position; the volume in the mandibular advancement position was larger and smaller than that in the head extension position and during mouth opening, respectively. The duration of the electromyogram in the head extension position was longer than that in the mandibular advancement position, without differences in the amplitude. Thus, swallowing ability in the supine position was more impaired with mandibular advancement, relative to neutral and head extension positions, but less than that observed with mouth opening. Although unconfirmed by electromyogram, our findings suggest that head extension might improve airway patency by reducing the impairment of swallowing ability compared with mandibular advancement.

Update on oral appliance therapy.

Oral appliances are increasingly recommended for selected patients with obstructive sleep apnoea (OSA) and those who do not tolerate nor prefer continuous positive airway pressure. The most commonly used oral appliance advances the lower jaw during sleep, the so-called mandibular advancement device (MAD). Patients seek treatment because of disturbing snoring, daytime symptoms, apnoeas that disturb sleep and the longer term consequences with regard to cardiovascular risks. MADs reduce the apnoea-hypopnoea index, although to various degrees among patients. Effects on daytime sleepiness have been observed mainly among the more severe OSA patients. Blood pressure may be reduced in MAD-treated OSA patients. There is, however, uncertainty about which patients will respond to this therapy in terms of apnoea reductions, decreased sleepiness and other symptoms, and reduced risk for future impaired health. The occurrence of side-effects also remains difficult to predict at present. The majority of sleep apnoea patients suffer from various comorbidities in terms of cardiovascular diseases, type 2 diabetes and depression. The most recent findings indicate that phenotyping of patients, considering various aspects of this multifaceted disease, will shed more light on the indications for MADs in patients with nightly sleep breathing disturbances. This review summarises the most recent knowledge about MAD treatment.

Risk Factors for Perioperative Respiratory Failure following Mandibular Distraction Osteogenesis for Micrognathia: A Retrospective Cohort Study.

BACKGROUND: The frequency of respiratory events in the perioperative period, and optimal duration of intubation during early mandibular distraction osteogenesis activation, are poorly understood. This study assesses potential risk factors associated with perioperative respiratory events, particularly the need for reintubation, following mandibular distraction osteogenesis surgery. METHODS: A retrospective review was conducted for infants (younger than 1 year) undergoing mandibular distraction osteogenesis for tongue-based airway obstruction between November of 2010 and December of 2017. Univariate and multivariate analyses of sentinel events and outcomes were performed. RESULTS: Ninety infants (median age, 35 days) were included (50 percent were syndromic). Twenty-seven subjects (30 percent) experienced a respiratory event requiring intervention before discharge, including 14 subjects who failed initial extubation. Subjects extubated earlier than postoperative day 5 failed extubation more frequently (33%) compared to those extubated later (9%; p = 0.005). Respiratory events occurred more frequently when extubation was attempted at distraction lengths of 5 mm or less (42 percent) compared to greater than 5 mm (21 percent; p = 0.032). Logistic regression modeling showed that syndromic status (OR, 14.8) and secondary airway anomaly (OR, 6.1) were significant predictors for respiratory events, whereas greater length of distraction at the time of extubation was protective (OR, 0.8; p < 0.05). CONCLUSIONS: Postoperative intubation of at least 5 days with associated mean distraction of 5 mm appears to be associated with successful extubation trial following mandibular distraction osteogenesis surgery. Patients with congenital syndromes and secondary airway anomalies are more likely to experience perioperative respiratory events. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

Heat-moulded versus custom-made mandibular advancement devices for obstructive sleep apnoea: a randomised non-inferiority trial.

RATIONALE: Custom-made mandibular advancement devices (MADs) are reported as providing higher efficacy rates compared with thermoplastic heat-moulded MADs but at the price of higher costs and treatment delays. OBJECTIVE: To determine whether a thermoplastic heat-moulded titratable MAD (ONIRIS; ONIRIS SAS, Rueil Malmaison, France) is non-inferior to a custom-made acrylic titratable MAD (TALI; ONIRIS SAS, Rueil Malmaison, France) for obstructive sleep apnoea (OSA). METHODS: We conducted a multicentre, open, randomised controlled trial of patients with OSA refusing or not tolerating continuous positive airway pressure (CPAP). Participants were randomly assigned to a thermoplastic heat-moulded titratable device or a custom-made acrylic device for 2 months with stratification by centre and OSA severity. The non-inferiority primary outcome was a ≥50% reduction in apnoea-hypopnoea index (AHI) or achieving AHI <10 events/hour at 2 months. The non-inferiority margin was preset as a difference between groups of 20% for the primary outcome in the per-protocol analysis. MAIN RESULTS: Of 198 patients (mean age 51 [SD, 12] years; 138 [72.6%] men; mean body mass index 26 [SD, 2.7] kg/m2; mean AHI 26.6/hour [SD, 10.4]), 100 received TALI and 98 ONIRIS. In per-protocol analysis, the response rate was 51.7% in the TALI group versus 53.6% in the ONIRIS group (absolute difference 1.9%; 90% CI: 11% to 15%, within the non-inferiority margin). Effectiveness was the same for severity, symptoms, quality of life and blood pressure reduction. Patients in ONIRIS group reported more side effects and adherence was slightly better with TALI. CONCLUSION: In patients with OSA refusing or not tolerating CPAP, the thermoplastic heat-moulded titratable MAD was non-inferior in the short-term to the custom-made acrylic MAD. TRIAL REGISTRATION NUMBER: NCT02348970.

Oral appliance for Obstructive Sleep Apnea: Prototyping and Optimization of the Mandibular Protrusion Device.

Obstructive Sleep apnea is a public health problem. This disease is associated with daytime sleepiness, increased motor vehicle accidents, heart failure and stroke. Treatment options include weight loss, positive airway pressure, pharyngeal and orthognatic surgery. However, selected patients have good response to oral appliances devices that intended to protrude and stabilize the mandible mechanically during the night in order to reduce the collapsibility of the upper airway. Selection of patients includes primary snoring, mild, moderate and positional apnea. The perfect mandibular advance device has not yet been designed. For these reasons, the objective of this paper is to present a new thermoadjustable chair-side oral appliance. Device integrates the best characteristics of custom made and boils and bite previous designs and minimizes inconveniences and possible side effects. The device is a titratable mandibular advancement appliance. It consists of two independent prefabricated trays adaptable to the shape of adult dental arch and linked to each other by a protrusion mechanism. Each tray contains a hard outer shell and a soft thermoplastic resin inner body. The position of the jaw can be adjusted by moving an aluminum rack into, or out from, the guide so the ratchet may get locked into a certain position ensuring the length of the mechanism. The protrusion mechanism is fixed to the splint using small rings that are articulated over a "t" button. Our prototype satisfies the requirements of an effective oral appliance, in terms of retention, comfort, safety and efficacy. It is easy to fit, durable, low cost, quickly titratable, not bulky and easy cleaning. Thermoplastic appliances are specially used like a predictor of treatment response in apnea patients. The device described is a cost-effective introduction to mandibular advancement technology. A qualified dentist or trained sleep doctor could mitigate dental side effects and reduce their incidence.

Long-term side effects of sleep apnea treatment with oral appliances: nature, magnitude and predictors of long-term changes.

OBJECTIVES: Oral appliances for the treatment of obstructive sleep apnea (OSA) reduce upper airway collapse by advancing the mandible (OAm) and associated soft tissues. OAm are well tolerated but have side effects, mainly dental movement. It is not yet clear whether there are irreversible skeletal changes associated with treatment. As oral appliance treatment for OSA is a life-long therapy, careful and extended follow-up of patients is required. The objectives of this study were to evaluate the magnitude and progression of the dental and skeletal changes associated with long-term treatment, in addition to determining the predictors of the changes. METHODS: Lateral cephalograms of adults treated for primary snoring or mild to severe OSA with a custom-made titratable OAm for a minimum of eight years were retrospectively studied. The magnitude and rate of progression of any changes over time was determined and initial patient and dental characteristics were investigated as possible predictors of the observed side effects. RESULTS: Records of 62 patients with an average treatment time of 12.6 years (range:8-21 years) were included. Cephalometric analysis revealed significant (p < 0.001) maxillary incisor retroclination (mean of ≈6°) and mandibular incisor proclination (mean of ≈8°) over the observation period. Maxillary incisors demonstrated a constant rate of retroclination -0.5°/year, the rate of mandibular incisors proclination was variable. The number of treatment years was significantly associated with these variables (p < 0.001). A greater body mass index (BMI) and Subspinale, Nasion, Supramentale angle (ANB) were associated with more maxillary and mandibular incisor proclination respectively. Although statistically significant (p < 0.001) skeletal changes were noted over this extended observation period, the difference in the Sella, Nasion, Supramentale point B (SNB) and mandibular plane angles were approximately 1° and were deemed not clinically significant. CONCLUSIONS: This study represents the longest observation period to date examining OAm side effects with up to 21 years of follow up for some patients. It confirms that there are significant and progressive dental changes with prolonged OAm use. Conversely, over the same time period skeletal or postural changes were negligible. Additionally, treatment duration was the predictor consistently associated with the magnitude of the observed side effects.

Long-term dental and skeletal effects of mandibular advancement devices in adults with obstructive sleep apnoea: A systematic review.

OBJECTIVE: This systematic review aimed to clarify whether there are any significant long-term sequelae to wearing mandibular advancement devices focusing on dental and skeletal effects in adults with OSA. MATERIALS AND METHODS: Databases, including PubMed, Medline, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and SAGE Journals. Hand searches and grey literature were also used. A piloted data collection form was used to extract the appropriate data. RESULTS: Twenty-three reports of 19 studies were included. Five had serious risk of bias while 18 had moderate risk of bias. Meta-analysis revealed a significant change in overbite and overjet. I-squared analysis showed a high level of statistical heterogeneity. A moderate correlation was found between wear time and amount of change. CONCLUSION: Mandibular advancement devices will cause a small but statistically significant change in the dentition of long-term wearers. Skeletal changes are generally secondary to dental changes.

Modified Mandibular Sagittal Split Osteotomy.

INTRODUCTION: Mandibular osteotomies aim to displace the dental arch to the necessary position, ideally without limitation, while preserving inferior alveolar nerve (IAN) function. Supraforaminal osteotomies offer nerve safety but limit the extent of advancement, whereas Epker and Obwegeser-Dal Pont osteotomies enable unchallenged mandibular advancement but are associated with an inferior border notch. Here, we describe a new technique to avoid such disadvantages. TECHNICAL NOTE: The beginning of the procedure was similar to Epker's technique, with sectioning of the lingual cortex up to the level of the lingula. Sectioning of the buccal cortex was stopped 3 to 4 mm above the inferior border and then performed horizontally up to the gonial angle in total thickness. The inferior border periosteum and muscles attachments were conserved and hence, appropriately vascularized. DISCUSSION: This technique offers 4 advantages: absence of the inferior border notch, lower risk of damage to the IAN than with Epker's technique, sufficiently large bony surface to obtain bone healing as in Epker's technique, and no limitation to setback movement in contrast to Obwegeser-Dal Pont's or the supraforaminal osteotomy techniques.

Use of bibloc and monobloc oral appliances in obstructive sleep apnoea: a multicentre, randomized, blinded, parallel-group equivalence trial.

Background: The clinical benefit of bibloc over monobloc appliances in treating obstructive sleep apnoea (OSA) has not been evaluated in randomized trials. We hypothesized that the two types of appliances are equally effective in treating OSA. Objective: To compare the efficacy of monobloc versus bibloc appliances in a short-term perspective. Patients and methods: In this multicentre, randomized, blinded, controlled, parallel-group equivalence trial, patients with OSA were randomly assigned to use either a bibloc or a monobloc appliance. One-night respiratory polygraphy without respiratory support was performed at baseline, and participants were re-examined with the appliance in place at short-term follow-up. The primary outcome was the change in the apnoea-hypopnea index (AHI). An independent person prepared a randomization list and sealed envelopes. Evaluating dentist and the biomedical analysts who evaluated the polygraphy were blinded to the choice of therapy. Results: Of 302 patients, 146 were randomly assigned to use the bibloc and 156 the monobloc device; 123 and 139 patients, respectively, were analysed as per protocol. The mean changes in AHI were -13.8 (95% confidence interval -16.1 to -11.5) in the bibloc group and -12.5 (-14.8 to -10.3) in the monobloc group. The difference of -1.3 (-4.5 to 1.9) was significant within the equivalence interval (P = 0.011; the greater of the two P values) and was confirmed by the intention-to-treat analysis (P = 0.001). The adverse events were of mild character and were experienced by similar percentages of patients in both groups (39 and 40 per cent for the bibloc and monobloc group, respectively). Limitations: The study shows short-term results with a median time from commencing treatment to the evaluation visit of 56 days and long-term data on efficacy and harm are needed to be fully conclusive. Conclusion: In a short-term perspective, both appliances were equivalent in terms of their positive effects for treating OSA and caused adverse events of similar magnitude. Trial registration: Registered with ClinicalTrials.gov (#NCT02148510).

Dental and skeletal long-term side effects of mandibular advancement devices in obstructive sleep apnea patients: a systematic review with meta-regression analysis.

Background: Mandibular advancement devices (MAD) are effective in reducing apnea episodes and they are frequently used as first-line therapy in obstructive sleep apnea (OSA) patients. Objectives: The MAD must be used every night for a lifetime and since it performs its function discharging the forces on dental elements the aim of this systematic review was to identify the dental and skeletal long-term side effects of MAD therapy and to evaluate the influence of time on them in OSA or snoring patients. Search Methods: An electronic search was performed in MEDLINE, Cochrane Database, Google Scholar Beta, Scopus, and LILACS. Studies until 4 April 2018 were analysed, without language restrictions. Selection Criteria: Randomized controlled trials and cohort studies investigating dental and/or skeletal side effects on adult patients wearing MAD for OSA or snoring treatment with at least 2 years follow-up were included and independently evaluated by two investigators. Data Collection and Analysis: The quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) and the risk of bias by means of Cochrane's tools. For each study included and for each dental and/or skeletal parameter, the difference in means and 95% CI was calculated between baseline and follow-up. Results: Twenty-one studies with follow-up between 2 and 11 years were included. The side effects reported were a reduction in overjet, overbite, and in the upper incisor inclination, and an increase in lower incisor inclination, A point-Nasion-B point, and anterior facial height. The meta-regression analysis showed that the side effects were influenced by the therapy duration for all parameters (P < 0.05). The quality of evidence was low/moderate. Conclusions: MAD therapy produces time-related dental and skeletal side effects. After a long period of treatment, the dental side effects are clinically relevant and therefore the clinician should inform the patients about this issue. Since the side effects are progressive, patients need to be continuously monitored over time. Registration: The study protocol was not registered.