The study was performed a posteriori, once the patients were diagnosed and treated. This research was performed by the Departments of Pulmonology, Neurophysiology, Otorhinolaryngology, Radiology and Odontology that make up the Sleep Unit of the Gómez Ulla Central Defense Military Hospital (HCD). This study is a retrospective, observational longitudinal study and was approved by the ethical committee in the same institution with number 49/18. All methods used in this study were performed in accordance with the Declaration of Helsinki. Patient gave their written consent to be treated with MADs, knowing their long-term side effects and that their data could be used for the elaboration of future studies.
The sample was made up of patients with the health insurance of the Spanish armed forces (ISFAS). Patietns were reffered to the Dentistry Department of the HCD, after being diagnosed with mild to moderate SAHS, for MAD theraphy.
Consecutive non-probabilistic sampling. A total of 46 patients, of both sexes, without age limits, were recruited. They were diagnosed with mild to moderate SAHS by previously conducted polysomnography (PSG).
Patients who were diagnosed with severe SAHS by PSG, a central component of SAHS, comorbidities of cardiovascular diseases, presence of any sign or symptom of temporomandibular joint pathology, active periodontal disease with loss of major bone support in 50% of teeth per hemiarcade, absence of more than 50% of teeth per hemiarcade, lateral radiographs of the skull in a state of dental non-occlusion and where the hyoid bone could not be observed.
Patients participating in the study underwent a lateral X-ray of the skull, in the natural position of the head and in dental occlusion, with the Instrumentarium ORTHOPANTOMOGRAPH OP300 (Finland). The natural position of the head was obtained following the methodology described by Moorees and Kean in 1958[7]. A cephalometric study was carried out where the craniofacial structure was examined, and patients were classified according to their facial biotype. The cephalometric study was carried out and analysed by the same person, and the measurements were made using Dolphin imaging® cephalometric diagnostic software, Chatsworth; CA, U.S.A; through which the cephalometric prescription FACE® was used. Jarabak’s spheres of percentage were analysed, wich was determined thanks to the average obtained between the anterior facial height (nasion-menton distance) and posterior facial height (sella-gonion distance) The final result of the classification of the 46 patients was, according to this methodology, brachyfacial (n=16), mesofacial (n=14) and dolichofacial (n=16).
The brachyfacial pattern shows hypodivergent growth, where the lower facial height is decreased, being represented in the 64-80% interval. (Fig. 1.)
The dolichofacial pattern is characterized by hyperdivergent, where the anterior facial height is increased, being represented in the 54-58& interval. (Fig. 2.)
The mesofacial skeletal pattern is one whose growth is within normal patterns, being represented in the 59-63% interval. (Fig. 3.)
The cephalometric points used in the study were: (Fig. 4.)
The device in our study was made with two independent splints that are fused with acrylic and two lateral unidirectional screws that classifies this kind of MAD as an adjustable advance type. (Fig. 5.)
This device is dental supported, and the splints must be made extending 3 to 5 mm beyond the dental equator to avoid dental side effects [8]. The constructive bite to advance the mandible was the same in all groups of patients. It was 70% of the protrusive maximum and was carried out using the George Gauge.
The patients were instructed on how to place the MAD intraorally and had at least a 3 month trial period to adjust to the MAD before performing the second polysomnographic test.
All patients had an initial polysomnographic study that diagnosed mild to moderate SAHS. The PSG system used in this study was the NET-BEACON.
The MAD therapeutic validation examination was carried out by means of a second nightly polysomnographic examination. Finally, we had two PSG recording, the first one was the diagnosis and the second one was to check the therapeutic effect of the MAD. The following PSG parameters were evaluated:
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Respiratory Disturbance Index (RDI) is the number of apnoeas and hypopnoeas per hour, along with the respiratory efforts associated with micro awakening. The patient is classified as mild if they have 5 to 14 events per hour, moderate if they have 15 to 30 events per hour and severe if they have more than 30 events per hour. The MAD treatment success rate was established to achieve a reduction in the RDI to a value < 10 and > 50% RDI reduction compared with baseline.
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Oxygen desaturation index (ODI) is the number of episodes of oxygen desaturation at least 4%/hour.
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Number of arousals or awakenings are brief alerts of the brain that interrupt the structure of dreams, without having to wake up the subject. Thy are detected through the EEG.
Shapiro-Wilk test was used to choose the parametric or non-parametric tests. The quantitative variables were described with the arithmetic mean with its standard deviation or the median with its interquartile range. We used the absolute and relative frequencies (%) for qualitative variables. The hypothesis tests used were Pearson’s chi-squared test, paired sample Student's t test, the Wilcoxon test, one-way ANOVA, Kruskal-Wallis test and Mann-Whitney U test. A p < 0.05 was considered statistically significant. Data were analysed using the Statistical Package for Social Sciences (SPSS), version 25 for Windows (Chicago, IL, USA). Consecutive non-probabilistic sampling was chosen.