Ghizlane Aarab

Oral Appliance Therapy versus Nasal Continuous Positive Airway Pressure in Obstructive Sleep Apnea: A Randomized, Placebo-Controlled Trial

Background: Previous randomized controlled trials have addressed the efficacy of mandibular advancement devices (MADs) in the treatment of obstructive sleep apnea (OSA). Their common control condition, nasal continuous positive airway pressure (nCPAP), was frequently found to be superior to MAD therapy. However, in most of these studies, only nCPAP was titrated objectively but not MAD. To enable an unbiased comparison between both treatment modalities, the MAD should be titrated objectively as well. Objective: The aim of the present study was to compare the treatment effects of a titrated MAD with those of nCPAP and an intra-oral placebo device. Methods: Sixty-four mild/moderate patients with obstructive sleep apnea (OSA; 52.0 ± 9.6 years) were randomly assigned to three parallel groups: MAD, nCPAP and placebo device. From all patients, two polysomnographic recordings were obtained at the hospital: one before treatment and one after approximately 6 months of treatment. Results: The change in the apnea-hypopnea index (ΔAHI) between baseline and therapy evaluation differed significantly between the three therapy groups (ANCOVA; p = 0.000). No differences in the ΔAHI were found between the MAD and nCPAP therapy (p = 0.092), whereas the changes in AHI in these groups were significantly larger than those in the placebo group (p = 0.000 and 0.002, respectively). Conclusion: There is no clinically relevant difference between MAD and nCPAP in the treatment of mild/moderate OSA when both treatment modalities are titrated objectively.

Long-term follow-up of a randomized controlled trial of oral appliance therapy in obstructive sleep apnea.

Background: Long-term trials are needed to capture information regarding the persistence of efficacy and loss to follow-up of both mandibular advancement device (MAD) therapy and continuous positive airway pressure (CPAP) therapy. Objectives: The aim of the study was to compare these treatment aspects between MAD and nasal CPAP (nCPAP) in a 1-year follow-up. Methods:Forty-three mild/moderate obstructive sleep apnea patients (52.2 ± 9.6 years) with a mean apnea-hypopnea index (AHI) of 20.8 ± 9.9 events/h were randomly assigned to two parallel groups: MAD (n = 21) and nCPAP (n = 22). Four polysomnographic recordings were obtained: one before treatment, one for the short-term evaluation, and two recordings 6 and 12 months after the short-term evaluation. Excessive daytime sleepiness (EDS) was also evaluated at the polysomnographic recordings. Results: The initially achieved improvements in the AHI remained stable over time within both groups (p = 0.650). In the nCPAP group, the AHI improved 4.1 events/h more than in the MAD group (p = 0.000). The EDS values showed a gradual improvement over time (p = 0.000), and these improvements were similar for both groups (p = 0.367). In the nCPAP group, more patients withdrew from treatment due to side effects than in the MAD group. Conclusions: The absence of significant long-term differences in EDS improvements between the MAD and the nCPAP groups with mild/moderate obstructive sleep apnea may indicate that the larger improvements in AHI values in the nCPAP group are not clinically relevant. Moreover, nCPAP patients may show more problems in accepting their treatment modality than MAD patients.

Variability in the Apnea-Hypopnea Index and Its Consequences for Diagnosis and Therapy Evaluation

Background: The apnea-hypopnea index (AHI) is frequently used to recognize obstructive sleep apnea (OSA) and to evaluate therapy. Objectives: The aim of this study was to determine the AHI variability during a 10-week period, and to discuss its consequences for diagnosis and therapy evaluation. Methods: Fifteen OSA patients (50.8 ± 11.2 years) underwent four polysomnographic (PSG) recordings, with a mean interval between recordings of 3.3 weeks. Results: No differences were found in the average AHI values of the four PSG recordings (p = 0.985). Nevertheless, pooling all data of the 15 participants yielded a smallest detectable difference for AHI of 12.8. Linear regression between the individual means and standard deviations (SDs) of AHI showed that participants with a higher AHI tended to have a higher SD (p < 0.044). Conclusions: These results suggest a considerable intra-individual variability in AHI recordings. Hence, a single-night recording can only recognize OSA when the AHI lies outside a cutoff band surrounding the AHI cutoff point. AHI variability should also be taken into account when evaluating OSA therapy. In this context, it should be noted that it is mainly the approach that we would like to convey to the reader and not the cutoff values per se.

The effect of raising the bite without mandibular protrusion on obstructive sleep apnoea

It has recently been suggested that wearing a maxillary occlusal splint (i.e. a hard acrylic resin dental appliance that covers the occlusal surfaces of the maxillary dentition and that is being indicated for the treatment of, e.g. temporomandibular pain) may be associated with a risk of aggravating obstructive sleep apnoea (OSA). The present study tested the hypothesis that raising the bite without mandibular protrusion in OSA patients is associated with an increase in the apnoea-hypopnoea index (AHI). Eighteen OSA patients (13 men; 49·5 ± 8·1 years old) received a mandibular advancement device in 0% protrusion of the mandible (0%MAD). The MAD caused a bite rise of 6 mm as measured interincisally. Polysomnographic recordings were obtained at baseline and with the 0%MAD in situ. No statistically significant difference in AHI was noted between the baseline night and the 0%MAD night. However, nine patients had an aggravation in AHI during the night they used the 0%MAD. Taking into account the previously established smallest detectable difference of 12·8 in AHI, the AHI increased in only two of the patients. The outcomes of this study suggest that an increased jaw gape without mandibular protrusion might be associated with a risk of aggravation of OSA for some, but not for all OSA patients. Dental practitioners should be aware of this possible association when treating patients with oral devices that raise the bite.

Three-dimensional imaging of the upper airway anatomy in obstructive sleep apnea: a systematic review

INTRODUCTION The pathogenesis of upper airway collapse in people with obstructive sleep apnea (OSA) is not fully understood. The aim of this study was to systematically review the literature in order to assess the most relevant anatomical characteristics of the upper airway related to the pathogenesis of OSA by analyzing the three-dimensional upper airway anatomy. METHOD A PICO (population/patient, intervention, comparison, outcome) search strategy, focusing on the upper airway anatomy of people with OSA, was conducted using the following databases: MEDLINE (PubMed), Excerpta Medica database (EMBASE), Web of Science, and Cochrane Library. The studies in which three-dimensional images were made from the participants who were awake and in the supine position during quiet breathing were selected in this systematic review. RESULTS Of the 758 unique retrieved studies, eight fulfilled the criteria for this systematic review. The minimum cross-sectional area of the upper airways of people with OSA, which is influenced by many factors such as hard and soft tissues surrounding the upper airway, was significantly smaller than that of those without OSA. CONCLUSION Within the limitation of the selected studies, this systematic review suggested that a small minimum cross-sectional area is the most relevant anatomical characteristic of the upper airway related to the pathogenesis of OSA.

A new definition of dental sleep medicine

A new definition of dental sleep medicine F. LOBBEZOO*, G. AARAB*, P . WETSELAAR*, A. HOEKEMA* ‡ , J . DE LANGE § & N. DE VRIES* ** *Department of Oral Kinesiology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, Department of Oral and Maxillofacial Surgery, Tjongerschans Hospital, Heerenveen, Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, Groningen, Department of Oral and Maxillofacial Surgery, Academic Medical Center (AMC) and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Amsterdam, Department of Otorhinolaryngology, Head and Neck Surgery, OLVG West, Amsterdam, The Netherlands and **Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine and Health Sciences, Antwerp University Hospital (UZA), Antwerp, Belgium

Accuracy of MDCT and CBCT in three-dimensional evaluation of the oropharynx morphology

Objective To assess the accuracy of five different computed tomography (CT) scanners for the evaluation of the oropharynx morphology. Methods An existing cone-beam computed tomography (CBCT) data set was used to fabricate an anthropomorphic phantom of the upper airway volume that extended from the uvula to the epiglottis (oropharynx) with known dimensions (gold standard). This phantom was scanned using two multi-detector row computed tomography (MDCT) scanners (GE Discovery CT750 HD, Siemens Somatom Sensation) and three CBCT scanners (NewTom 5G, 3D Accuitomo 170, Vatech PaX Zenith 3D). All CT images were segmented by two observers and converted into standard tessellation language (STL) models. The volume and the cross-sectional area of the oropharynx were measured on the acquired STL models. Finally, all STL models were registered and compared with the gold standard. Results The intra- and inter-observer reliability of the oropharynx segmentation was fair to excellent. The most accurate volume measurements were acquired using the Siemens MDCT (98.4%; 14.3 cm3) and Vatech CBCT (98.9%; 14.4 cm3) scanners. The GE MDCT, NewTom 5G CBCT, and Accuitomo CBCT scanners resulted in smaller volumes, viz., 92.1% (13.4 cm3), 91.5% (13.3 cm3), and 94.6% (13.8 cm3), respectively. The most accurate cross-sectional area measurements were acquired using the Siemens MDCT (94.6%; 282.4 mm2), Accuitomo CBCT (95.1%; 283.8 mm2), and Vatech CBCT (95.3%; 284.5 mm2) scanners. The GE MDCT and NewTom 5G CBCT scanners resulted in smaller areas, viz., 89.3% (266.5 mm2) and 89.8% (268.0 mm2), respectively. Limitations Images of the phantom were acquired using the vendor-supplied default airway scanning protocol for each scanner. Conclusion Significant differences were observed in the volume and cross-sectional area measurements of the oropharynx acquired using different MDCT and CBCT scanners. The Siemens MDCT and the Vatech CBCT scanners were more accurate than the GE MDCT, NewTom 5G, and Accuitomo CBCT scanners. In clinical settings, CBCT scanners offer an alternative to MDCT scanners in the assessment of the oropharynx morphology.

Dental Sleep Medicine redefined

Dear Editor, In 1999, Prof. Gilles Lavigne (Université de Montréal, QC, Canada) and coworkers published a comprehensive review, entitled ‘Sleep disorders and the dental patient’ [1]. This landmark article was the first to describe in detail several common sleep disorders of interest to dentists, viz., not only snoring and obstructive sleep apnea but also sleep bruxism, xerostomia, hypersalivation, gastroesophageal reflux, and orofacial pain. Over the years, the publication by Lavigne et al. [1] was cited mainly in dental journals, which suggests good visibility of the topic amongst dental researchers. Consequently, one would have expected a broadening of Dental Sleep Medicine as a discipline within dentistry. However, Dental Sleep Medicine Academies worldwide kept their focus on the management of sleep-related breathing disorders, including snoring and obstructive sleep apnea (OSA), with oral appliance therapy and upper airway surgery. Since sleep disorders other than sleep-disordered breathing may have oral and maxillofacial causes and consequences, Lobbezoo et al. [2] formulated a new definition for Dental Sleep Medicine:

The Effects of Noncontinuous Positive Airway Pressure Therapies on the Aerodynamic Characteristics of the Upper Airway of Obstructive Sleep Apnea Patients: A Systematic Review

PURPOSE The effects of noncontinuous positive airway pressure (non-CPAP) therapies on the airflow in the upper airway in obstructive sleep apnea (OSA) patients are not completely clear yet. Therefore, the primary aim of this systematic review was to determine the effects of various non-CPAP therapies on the aerodynamic characteristics of the upper airway in OSA patients. MATERIALS AND METHODS A PICO (population or patient, intervention, comparison, outcome) search strategy, focusing on the effects of various non-CPAP therapies on the aerodynamic characteristics of the upper airway (ie, velocity, wall shear stress, wall static pressure, airway resistance, pressure drop, and pressure effort) of OSA patients, was conducted in the following databases: MEDLINE (PubMed), Embase (Excerpta Medica), and Web of Science. In this systematic review, the inclusion criteria were 1) adults diagnosed with OSA by polysomnography, 2) treatment outcome assessed by a second polysomnography, and 3) computational fluid dynamics (CFD) applied. RESULTS Of 51 unique studies retrieved, 9 fulfilled the criteria for this systematic review. Seven studies were on maxillomandibular advancement (MMA) surgery, and 2 were on mandibular advancement device (MAD) therapy. The aerodynamic characteristics of the upper airway improved in OSA patients who underwent MMA surgery. However, the studies on MMA surgery included only responders to MMA surgery. In the responders to MAD therapy, the velocity, wall static pressure, and airway resistance of the upper airway decreased. In nonresponders to MAD therapy, the wall static pressure and airway resistance of the upper airway increased. CONCLUSIONS This systematic review suggests that MMA surgery and MAD therapy may improve several aerodynamic characteristics of the upper airway in OSA patients by CFD analysis. However, because of limitations of the selected studies, there is not enough evidence yet to support CFD analysis as a routine tool to predict the treatment outcome in OSA patients.

Bruxism in dentists’ families

Bruxism is defined as a repetitive jawmuscle activity that is characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. It is indicated as either sleep bruxism or awake bruxism, depending on its circadian phenotype.1 While the jawmuscle activity as such does not justify extensive diagnosis and treatment,2 sleep bruxism that goes with severe (especially anterior) tooth wear, highintensity pain in the masticatory muscles and temporomandibular joints, or penetrating grinding noises does urge bruxists to seek dental help for their condition. During the consultation with the dentist, the oral history often touches upon the common observation that other family members grind their teeth as well, leading to the question whether or not bruxism runs in families. A recent, quasisystematic review of the literature now enables an evidencebased answer to the frequently asked question whether bruxism is hereditary: based on four family studies, five twin studies, and one DNA study, bruxism appears to be partly genetically determined.3