The effect of different hybrid rigid internal fixation techniques on the postoperative stability following a mandibular advancement using a bilateral sagittal split ramus osteotomy: A retrospective three-dimensional comparative study.

OBJECTIVE: To three-dimensionally evaluate post-operative mandibular stability following bilateral sagittal split ramus osteotomies between hybrid and non-hybrid rigid internal fixation techniques. MATERIALS AND METHOD: Seventy adults with skeletal class II deformity who underwent bilateral split sagittal osteotomy with mandibular advancement were included. Patients were divided into four groups based on their fixation techniques: hybrid technique (HT) groups I, II, and IV received a 4-hole 2 mm miniplate with either a bicortical screw (BS), additional 2 mm 4-hole miniplate, or two-hole miniplate, while non-HT group III received a 4-hole 2 mm miniplate with four mini-screws (MS). Measurements were taken pre-operatively (T0), immediately postoperatively (T1), and ≥1 year after surgery (T2) using 3D Slicer software. RESULTS: Age, sex, and follow-up period did not correlate significantly with postoperative relapse or stability. Significant differences were observed in the advancement on the right side between groups II, III, and IV and on the left side between groups I, III, and IV. However, the type of surgical intervention showed no significant effect on postoperative relapse and stability. All groups of fixations showed satisfactory stability with irrelevant relapse (< 2 mm or 2°). CONCLUSION: The study demonstrated satisfactory and comparable stability among different fixation groups on patients undergoing mandibular advancement following bilateral split sagittal osteotomy. The results highlighted the importance of considering the degree of advancement when planning orthognathic surgery and managing postoperative outcomes.

Mandibular Advancement vs CPAP for Blood Pressure Reduction in Patients With Obstructive Sleep Apnea.

BACKGROUND: Hypertension guidelines recommend diagnosis and treatment of obstructive sleep apnea (OSA) in patients with hypertension. The mandibular advancement device (MAD) is an oral appliance therapy for patients who decline or cannot tolerate continuous positive airway pressure (CPAP). OBJECTIVES: We compared the relative effectiveness of MAD vs CPAP in reducing 24-hour ambulatory blood pressure (BP). METHODS: In an investigator-initiated, randomized, noninferiority trial (prespecified margin 1.5 mm Hg), 321 participants aged ≥40 years with hypertension and increased cardiovascular risk were recruited at 3 public hospitals for polysomnography. Of these, 220 participants with moderate-to-severe OSA (apnea-hypopnea index ≥15 events per hour) were randomized to either MAD or CPAP (1:1). The primary outcome was the difference between the 24-hour mean arterial BP at baseline and 6 months. RESULTS: Compared with baseline, the 24-hour mean arterial BP decreased by 2.5 mm Hg (P = 0.003) at 6 months in the MAD group, whereas no change was observed in the CPAP group (P = 0.374). The between-group difference was -1.6 mm Hg (95% CI: -3.51 to 0.24, noninferiority P < 0.001). The MAD group demonstrated a larger between-group reduction in all secondary ambulatory BP parameters compared with the CPAP group, with the most pronounced effects observed in the asleep BP parameters. Both the MAD and CPAP improved daytime sleepiness, with the between-group difference similar (P = 0.384). There were no between-group differences in cardiovascular biomarkers. CONCLUSIONS: MAD is noninferior to CPAP for reducing 24-hour mean arterial BP in participants with hypertension and increased cardiovascular risk. (Cardiosleep Research Program on Obstructive Sleep Apnea, Blood Pressure Control and Maladaptive Myocardial Remodeling-Non-inferiority Trial [CRESCENT]; NCT04119999).

The predictive value of mandibular advancement maneuvers during drug-induced sleep endoscopy for treatment success of oral appliance treatment in obstructive sleep apnea: a prospective study.

STUDY OBJECTIVES: To prospectively validate drug-induced sleep endoscopy with mandibular advancement maneuvers as a prediction tool for treatment success of oral appliance treatment (OAT). METHODS: Seventy-seven patients diagnosed with moderate obstructive sleep apnea were included and underwent drug-induced sleep endoscopy. The upper airway collapse was assessed using the VOTE classification. Additionally, three mandibular advancement maneuvers were performed to predict treatment success of OAT. If the maneuver was negative, the level and degree and configuration of the persistent collapse was described according to the VOTE classification. All patients were treated with OAT and completed a follow-up sleep study with OAT in situ without regard to their anticipated response to treatment. RESULTS: Sixty-four patients completed 6-month follow up. A positive jaw thrust maneuver proved to be significantly associated with favorable OAT response, whereas the chin lift maneuver and the vertical chin lift maneuver were not. Additionally, a persistent lateral oropharyngeal collapse when performing any mandibular advancement maneuver was significantly associated with unfavorable OAT response. CONCLUSIONS: The current findings suggest that a jaw thrust maneuver should be preferred over the chin lift maneuver for predicting OAT response. Patients with a positive jaw thrust maneuver should be counseled toward favorable OAT response, whereas those with persistent lateral oropharyngeal collapse should be advised about the likelihood of unfavorable OAT response. A negative jaw thrust maneuver did not prove to be a significant predictor for unfavorable response to OAT. Consequently, uncertainties arise regarding the justification of performing drug-induced sleep endoscopy solely for predicting the efficacy of OAT. However, the results of the current study could be influenced by heterogeneity in the assessment of respiratory parameters, variability in the performance of the mandibular advancement maneuvers, and the instability of bolus technique sedation. CLINICAL TRIAL REGISTRATION: Registry: Netherlands Trial Register; Name: Drug-induced Sleep Endoscopy: a prediction tool for success rate of oral appliance treatment; Identifier: NL8425; URL: https://www.onderzoekmetmensen.nl/en/trial/20741. CITATION: Veugen CCAFM, Kant E, Kelder JC, Schipper A, Stokroos RJ, Copper MP. The predictive value of mandibular advancement maneuvers during drug-induced sleep endoscopy for treatment success of oral appliance treatment in obstructive sleep apnea: a prospective study. J Clin Sleep Med. 2024;20(3): 353-361.

Comparative analysis of two custom-made mandibular advancement devices with varied designs for treating moderate to severe obstructive sleep apnea.

INTRODUCTION: Custom-made titratable mandibular advancement device (MAD) treatment can nowadays be considered a promising first-line treatment in patients with mild to severe obstructive sleep apnea (OSA). Specific manufacturing designs and titration mechanisms of MAD are on the market, characterized by their titration approach, vertical opening, and materials selection. The wing-designed MAD (SomnoDent® Flex™, SomnoMed Ltd, Sydney, Australia) has a lateral screw mechanism to advance the lower jaw in incremental steps of 0.1 up to 6.0 mm. The newer uniquely designed custom-made MAD with passive mouth closing (SomnoDent® Avant™ SomnoMed Ltd, Sydney, Australia) has a frontal exchangeable advancement strap of fixed lengths as a specific titration mechanism, all supporting freedom of lateral movement. We aimed to assess the associations between the type of MAD prescribed and OSA treatment outcome. METHODS: Data from 209 patients (165 male, mean age 53.9 (±10.9) years, median baseline BMI and AHI 27.02 [24.8; 29.7] kg/m2 and 22.8 [17.7; 31.6]/hour sleep, respectively) were collected. Of this cohort, 91 patients with the traditional, wing-based SomnoDent® Flex™ and 118 patients with SomnoDent® Avant™. All patients were diagnosed with a type 1 polysomnography demonstrating moderate to severe OSA (15 ≤ AHI ≤65 per hour sleep). The selected MAD was fitted in the so-called maximal comfortable protrusion. After 3 months of subjective titration until resolution of subjective symptoms and/or achieving physical limits, a checkup with validated home sleep monitoring was conducted. Treatment success was defined as "AHI reduction ≥50% with MAD compared to baseline AHI and AHI with MAD <10 events per hour". RESULTS: These real-world data set showed that 67% of patients achieved treatment success, with a statistically significant reduction in AHI from 22.8 [17.7; 31.6] to 7.45 [3.4; 15.0]/h sleep. The SomnoDent® Avant™ achieved 75% treatment success versus 56% for the traditional, wing-based SomnoDent® Flex™ (P < 0.05). Overall, AHI reduction was 70% for SomnoDent® Avant™ (P < 0.05) vs. 63% for SomnoDent® Flex™ (P < 0.05). CONCLUSIONS: This study shows that choice of MAD design can impact the treatment outcome and could become an important consideration in selecting the type of MAD for personalized treatment for OSA patients. While the results of the traditional wing-based MAD design were comparable to the therapeutic outcome with other titratable, custom-made MADs, the MAD with the passive mouth closing feature showed significantly greater reduction in total AHI potentially due to encouraged nasal breathing, reduced mouth breathing and lesser vertical opening thereby decreasing the probability of tongue base collapse.

Evaluation of mandibular motion in adolescents with skeletal class II division 1 malocclusion during mandibular advancement using clear functional aligners: a prospective study.

BACKGROUND: This study aimed to evaluate the characteristics of mandibular protrusive condylar trajectory in adolescents with skeletal Class II Division 1 malocclusion and the changes of condylar trajectory during mandibular advancement (MA) treatment using clear functional aligners. METHODS: This prospective study consisted of a cross-sectional study and a longitudinal study. In cross-sectional study, sixty-one adolescents were divided into two groups: Class I (n = 30) and Class II Division 1 (n = 31). The condylar trajectory was measured and compared using the Mann-Whitney U test. The longitudinal study was the MA treatment group using clear functional aligner and consisted of 16 participants from Class II Division 1group. The condylar trajectory was collected at three-time points: pre-treatment (T1), during MA treatment at approximately 3 months (T2, 105.6 days average), and at the end of MA treatment (T3, 237.6 days average). The changes at T1, T2, and T3, as well as the symmetry between the left and right condyles across all groups, were examined using the Wilcoxon paired test. RESULTS: A greater increase in the anteroposterior displacement and space displacement during protrusive movements was observed in the Class II Division 1 group compared with that in the Class I group, with a large difference being observed in the left and right condylar movements. The condylar anteroposterior displacement and space displacement decreased significantly at T2 and increased significantly at T3; however, no significant difference was observed between T1 and T3. A significant difference was observed between the condylar movement on the left and right sides at T1; however, no significant difference was observed at T2 and T3. CONCLUSIONS: Adolescents with Class II Division 1 malocclusion had higher protrusive capacity than those with Class I. Moreover, their left and right condylar motion was more asymmetric. The range of condyle motion decreased first and then increased during MA therapy, and the left and right condyle movement became more symmetrical, which may be the adaptive response of neuromuscular function to the changes in jaw position.

Efficacy of Oral Appliance for Mild, Moderate, and Severe Obstructive Sleep Apnea: A Meta-analysis.

OBJECTIVE: Oral appliances (OA) are the recommended first-line option for mild-to-moderate obstructive sleep apnea (OSA)-hypopnea. However, there is a lack of evidence to compare the effectiveness of OA in different severities of OSA. The purpose of this study was to investigate the therapeutic effects of preferred OA (tongue retention devices [TRD] and mandibular advancement device [MAD]) in different severities of OSA. DATA SOURCES: PubMed/MEDLINE, The Cochrane Library, and Web of Science. REVIEW METHODS: Concentrating on the efficacy of OA, 2 authors searched 3 databases up to November 10, 2022, independently and systematically, following the requirements and steps of the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. RESULTS: Ultimately, 42 studies with 2265 patients met the criteria for inclusion in OA. Overall, the apnea-hypopnea index improved by 48% (5.6), 67% (14.92), and 62% (32.1) in mild, moderate, and severe OSA, respectively. Subgroup analysis showed a significant difference between MAD and TRD efficacy in mild OSA (58% vs 21%). However, no significant difference was seen between MAD and TRD efficacy in moderate (67% vs 66%) and severe OSA (66% vs 51%). There was no significant difference across groups in the Epworth Sleepiness Scale, oxygen desaturation index (ODI), and lowest oxygen saturation (LSAT). CONCLUSION: Overall, both TRD and MAD are effective treatments for moderate and severe OSA. MAD is efficacious in mild OSA, while TRD requires further validation. Furthermore, mild-moderate and severe OSA received similar improvements in sleepiness, ODI, and LSAT. This study complements the evidence for the efficacy of OA.

Evaluation of bone contact area and intercondylar distance changes in orthognathic surgery - a comparison between BSSO and HSSO technique depending on mandibular displacement extent.

OBJECTIVES: The present study aims to assess the impact of bilateral and high oblique sagittal split osteotomy (BSSO/HSSO), as well as displacement distances and directions on the expected and achievable bone contact area (BCA) and changes in the intercondylar distance (ICD). The primary question addressed is whether mandibular splitting through BSSO results in a greater BCA and/or ICD when compared to splitting through HSSO. MATERIALS AND METHODS: Totally 80 mandibular displacements were performed on 20 fresh cadavers, for each subject, four splints were produces to facilitate mandibular advancement as well as setbacks of 4 and 8 mm. Pre- and postoperative CBCT scans were performed to plan the surgical procedures and to analyze the expected and achieved BCA and ICD. RESULTS: Regarding the maximum mandibular displacement, the expected BCA for HSSO/BSSO were 352.58 ± 96.55mm2 and 1164.00 ± 295.50mm2, respectively, after advancement and 349.11 ± 98.42mm2 and 1344.70 ± 287.23mm2, respectively, after setback. The achieved BCA for HSSO/BSSO were 229.37 ± 75.90mm2 and 391.38 ± 189.01mm2, respectively, after advancement and 278.03 ± 97.65mm2 and 413.52 ± 169.52 mm2, respectively after setback. The expected ICD for HSSO/BSSO were 4.51 ± 0.73 mm and 3.25 ± 1.17 mm after advancement and - 5.76 ± 1.07 mm and - 4.28 ± 1.58 mm after setback. The achieved ICD for HSSO/BSSO were 2.07 ± 2.9 mm and 1.7 ± 0.60 mm after advancement and - 2.57 ± 2.78 mm and - 1.28 ± 0.84 mm after setback. Significant differences between the BCA after HSSO and BSSO were at each displacement (p < 0.001), except for the achieved BCA after 8-mm setback and advancement (p ≥ 0.266). No significant differences were observed regarding ICD, except for the expected ICD after 8-mm setback and advancement (p ≤ 0.037). CONCLUSIONS: Compared to the virtual planning, the predictability regarding BCA and ICD was limited. ICD showed smaller clinical changes, BCA decreased significantly in the BSSO group. CLINICAL RELEVANCE: BCA and ICD might have been less important in choosing the suitable split technique. in orthognathic surgery.

Neurophysiological basis of respiratory discomfort improvement by mandibular advancement in awake OSA patients.

Patients with obstructive sleep apneas (OSA) do not complain from dyspnea during resting breathing. Placement of a mandibular advancement device (MAD) can lead to a sense of improved respiratory comfort ("pseudo-relief") ascribed to a habituation phenomenon. To substantiate this conjecture, we hypothesized that, in non-dyspneic awake OSA patients, respiratory-related electroencephalographic figures, abnormally present during awake resting breathing, would disappear or change in parallel with MAD-associated pseudo-relief. In 20 patients, we compared natural breathing and breathing with MAD on: breathing discomfort (transitional visual analog scale, VAS-2); upper airway mechanics, assessed in terms of pressure peak/time to peak (TTP) ratio respiratory-related electroencephalography (EEG) signatures, including slow event-related preinspiratory potentials; and a between-state discrimination based on continuous connectivity evaluation. MAD improved breathing and upper airway mechanics. The 8 patients in whom the EEG between-state discrimination was considered effective exhibited higher Peak/TTP improvement and transitional VAS ratings while wearing MAD than the 12 patients where it was not. These results support the notion of habituation to abnormal respiratory-related afferents in OSA patients and fuel the causative nature of the relationship between dyspnea, respiratory-related motor cortical activity and impaired upper airway mechanics in this setting.

Role of NF-κB in cardiac changes of obstructive sleep apnoea rabbits treated by mandibular advancement device.

BACKGROUND: Obstructive sleep apnoea (OSA) is an independent risk factor for cardiovascular diseases. We aimed to investigate the role of nuclear factor-kappa B (NF-κB) in the changes of cardiac structures in OSA rabbits treated by mandibular advancement device (MAD). METHODS: Eighteen male New Zealand white rabbits aged 6 months were randomly divided into three groups: control group, group OSA and group MAD. Hyaluronate gel was injected into the soft palate of the rabbits in group OSA and group MAD to induce OSA. The cone beam computer tomography (CBCT) of the upper airway and polysomnography (PSG) was performed to ensure successful modelling. CBCT and PSG were applied again to detect the effects of MAD treatment. All animals were induced to sleep in a supine position for 4-6 h a day for 8 weeks. Then the levels of NF-κB, Interleukin 6 (IL-6), Interleukin 10 (IL-10) and the proportion of myocardial fibrosis (MF) were detected. RESULTS: The higher activation of NF-κB, IL-6 and IL-10 were found in the OSA group than in the control group, leading to the increase of collagen fibres compared with the control group. Furthermore, the apnoea-hypopnea index (AHI) was positively correlated with the above factors. There were no significant differences between group MAD and the control group. CONCLUSION: The NF-κB pathway was activated in the myocardium of OSA rabbits, which accelerated the development of MF. Early application of MAD could reduce the activation of NF-κB in the myocardium and prevent the development of MF.

Exploring long-term changes and influencing factors of the upper airway in patients with a skeletal Class II relationship after mandibular advancement with maxillary setback surgery: A comprehensive 2-year follow-up investigation.

INTRODUCTION: The objective of this study was to investigate the 2-year postoperative change and influencing factors of the upper airway after mandibular advancement with maxillary setback surgery for patients with a skeletal Class II relationship. METHODS: Fifty-seven participants who underwent mandibular advancement with maxillary setback surgery were enrolled consecutively. Cone-beam computed tomography was performed preoperatively, 3 months postoperatively (T1), and 2 years (T2) postoperatively. All parameters were measured using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). RESULTS: The total volume (V), minimum cross-sectional area (CSAmin), and glossopharynx increased significantly in both the short-term (V, 13.33%; CSAmin, 33.03%; glossopharynx, 26.73%) and long-term (V, 10.19%; CSAmin, 23.18%; glossopharynx, 18.27%) after the surgery. Mandibular advancement, mandibular width increase, preoperative CSAmin, and body mass index (BMI) significantly affected 2-year postoperative V increases. Mandibular advancement and BMI significantly affected 2-year postoperative glossopharynx increases. Backward movement of point PNS may lead to a reduction of the nasopharynx; however, downward movement of point PNS, upward movement of point A, and increased maxillary width may compensate for this effect by increasing the likelihood of the nasopharynx opening. Furthermore, mandibular body length at T1 is positively associated with relapse rate ([T2 - T1] / T1) of V and CSAmin. CONCLUSIONS: Mandibular advancement amount, mandibular width increase, preoperative CSAmin, and BMI are the 4 factors for long-term V changes. Patients with a longer mandibular body length might have a lower relapse rate.

Clinical efficacy of the Invisalign mandibular advancement appliance: A retrospective investigation.

INTRODUCTION: This retrospective investigation aimed to determine whether the achieved changes in the treatment of Class II malocclusion were the same as those planned after the prescribed wear of an initial phase of Invisalign treatment with the mandibular advancement appliance (MAA) (Align Technology, Santa Jose, Calif). METHODS: All patients treated with the MAA and who satisfied inclusion/exclusion criteria were selected from a database of 16,500 patients treated with clear aligners by 16 orthodontists. The pretreatment, planned, and achieved overjet measurements were documented from data provided in Align Technology's software facility, ClinCheck. Changes in intermaxillary anteroposterior (AP) first permanent molar (FPM) relationships were evaluated using Geomagic Control X (3D systems, Rock Hill, SC) metrology software. RESULTS: Most of the 195 patients who satisfied the inclusion criteria were females (n = 104; 53.3%). The mean age was 12.62 ± 2.20 years. The pretreatment overjet was reduced from 6.49 ± 2.86 mm to 4.61 ± 2.22 mm after prescribed MAA wear, which was 42.5% of the planned outcome. The pretreatment AP FPM reduced from 3.14 ± 1.95 mm to 2.24 ± 2.51 mm, which was 31.3% of that planned. Thirty-eight (19.5%) patients experienced an increase in overjet where a reduction was planned. CONCLUSIONS: Less than half of the planned overjet reduction and less than a third of the planned AP FPM correction were achieved with the MAA. Almost 20% of patients completed the MAA phase of treatment with an increased overjet despite a reduction being planned.

Evaluation of condylar and mandibular movements on the upper airway during the use of mandibular advancement device for obstructive sleep apnea treatment.

OBJECTIVES: To evaluate the temporomandibular joint (TMJ), condylar and mandibular movements in obstructive sleep apnea (OSA) patients treated with mandibular advancement device (MAD) and to identify the influence of these anatomic factors on upper airway (UA) volume and polysomnographic outcomes after treatment. MATERIALS AND METHODS: Twenty OSA patients were prospectively treated with MAD. Clinical examinations, cone-beam computed tomography, and polysomnography were performed before MAD treatment and after achieving therapeutic protrusion. Polysomnographic variables and three-dimensional measurements of the TMJ, mandible, and upper airway were statistically analyzed. RESULTS: Condylar rotation, anterior translation, and anterior mandibular displacement were directly correlated with total UA volume, while vertical mandibular translation was inversely correlated with the volume of the inferior oropharynx. MAD treatment resulted in an increase in the volume and area of the superior oropharynx. There was no statistically significant correlation between condylar rotation and translation and polysomnographic variables. With MAD, there was a significant increase in vertical dimension, changes in condylar position (rotation and translation), and mandibular displacement. The central and medial lengths of the articular eminence were inversely correlated with condylar rotation and translation, respectively. The lateral length of the eminence was directly correlated with condylar translation, and the lateral height was directly correlated with condylar rotation and translation. CONCLUSION: Condylar and mandibular movements influenced UA volume. The articular eminence played a role in the amount of condylar rotation and translation. CLINICAL RELEVANCE: Individualized anatomical evaluation of the TMJ proves to be important in the therapy of OSA with MAD.

Self-reported oral moistening disorders in obstructive sleep apnoea: A scoping review.

BACKGROUND: Obstructive sleep apnoea (OSA) is a highly prevalent problem with significant consequences. Continuous positive airway pressure (CPAP) and oral mandibular advancement device (MAD) are considered the standard treatments for OSA. Patients may experience self-reported oral moistening disorders (OMDs) (i.e. xerostomia or drooling) at the beginning, throughout and after treatment. This affects oral health, quality of life and treatment effectiveness. The exact nature of the associations between OSA and self-reported OMD is still unknown. We aimed to provide an overview of the associations between self-reported OMD on the one hand and OSA and its treatment (namely CPAP and MAD) on the other hand. In addition, we sought to determine whether OMD affects treatment adherence. MATERIALS AND METHODS: A literature search in PubMed was performed up to 27 September 2022. Two researchers independently assessed studies for eligibility. RESULTS: In total, 48 studies were included. Thirteen papers investigated the association between OSA and self-reported OMD. They all suggested an association between OSA and xerostomia but not between OSA and drooling. The association between CPAP and OMD was addressed in 20 articles. The majority of studies have indicated xerostomia as a CPAP side effect; however, some have observed that xerostomia diminishes with CPAP therapy. In 15 papers, the association between MAD and OMD was investigated. In most publications, both xerostomia and drooling have been described as common side effects of MADs. These side effects are often mild and transient, and they improve as patients continue to use their appliance. Most studies found that these OMDs do not cause or are not a strong predictor of non-compliance. CONCLUSION: Xerostomia is a common side effect of CPAP and MAD, as well as a significant symptom of OSA. It may be regarded as one of the indicators of sleep apnoea. Moreover, MAD therapy can be associated with OMD. However, it seems that OMD may be mitigated by being adherent to the therapy.

Comparison of efficacy and usability of custom mandibular advancement devices fabricated with the conventional method and digital workflow: A pilot clinical study.

PURPOSE: To compare the effects of fabricating methods of custom monoblock mandibular advancement devices (MADs) on usability and efficacy in patients with mild and moderate obstructive sleep apnea (OSA). MATERIALS AND METHODS: Digitally fabricated custom MADs (dMADs) were produced for 11 OSA participants who had previously used conventionally fabricated custom MADs (cMADs). The participants answered a modified usability questionnaire for both MADs, and the average scores that were given to the questionnaire were evaluated by age, sex, and body mass index (BMI), and the scores of cMADs and dMADs were compared. After 6 months of usage of each MAD, the apnea-hypopnea index (AHI), mean and lowest oxygen saturations, and total sleep time were measured for efficacy assessment. Data were analyzed with Cronbach's alpha, Mann-Whitney U, Kruskal-Wallis, Wilcoxon signed-rank, one-way repeated measures analyses of variance, and Bonferroni tests (α = 0.05). RESULTS: Cronbach's alpha was found at 0.834 and 0.722 for the conventional and digital questionnaires, respectively. The usability scores of the dMADs were significantly higher than those of cMADs (p = 0.013). There was no difference in usability scores in terms of sex or BMI (p > 0.05). No statistically significant difference was found for cMAD (p = 0.113) among age groups; however, there was a significant difference for dMAD (p = 0.046). The AHI, mean, and lowest oxygen saturation values were significantly affected by MAD usage (p < 0.001). However, total sleep time values did not differ after the MAD treatments (p > 0.05). Significantly lower AHI and significantly higher lowest oxygen saturation values were observed with dMAD, while both appliances led to similar results for mean oxygen saturation and total sleep time values (p > 0.05). CONCLUSIONS: Participant usability scores were higher for digitally manufactured MADs than conventionally manufactured MADs. However, both conventional and digital MADs were found effective in decreasing the AHI levels and increasing the mean and lowest oxygen saturation values of the participants.

A finite element analysis of stress distribution with various directions of intermaxillary fixation using orthodontic mini-implants and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy.

OBJECTIVE: This finite element analysis (FEA) aimed to assess the stress distribution in the mandible and fixation system with various directions of the intermaxillary fixation (IMF) using mini-implants (MIs) and elastics following mandibular advancement with a bilateral sagittal split ramus osteotomy (BSSRO). MATERIALS AND METHODS: A total of nine mandibular advancement models were set according to the position of the MIs (1.6 mm in diameter, 8 mm in length) and direction of the IMF elastics (1/4 inch, 5 oz). Major and minor principal stresses in the cortical and cancellous bones, von Mises stresses in the fixation system (miniplate and monocortical screws), and bending angles of the miniplate were analysed. RESULTS: Compressive and tensile stress distributions in the mandible and von Mises stress distributions in the fixation system were greater in models with a Class III IMF elastic direction and a higher IMF elastic force than in models with a Class II IMF elastic direction and a lower IMF elastic force. The bending angle of the miniplate was negligible. CONCLUSIONS: Stress distributions in the bone and fixation system varied depending on the direction, amount of force, and position of IMF elastics and MIs. Conclusively, IMF elastics in the Class II direction with minimal load in the area close to the osteotomy site should be recommended.

Predictive factors of therapeutic response according to craniofacial skeletal biotype in patients with sleep apnea syndrome using mandibular advancement devices: a pilot study.

OBJECTIVES: To evaluate the influence of facial biotype in the therapeutic effect of mandibular advancement devices (MADs) according to polysomnographic records in patients diagnosed with sleep apnea-hypopnea syndrome (SAHS). MATERIALS AND METHODS: A total of 46 patients were recruited. Patients were classified according to facial biotype (mesofacial, brachyfacial, or dolichofacial). The quantitative variables were described as the arithmetic mean and standard deviation or the median and interquartile range. Hypothesis tests used were Pearson's chi-square, paired-sample Student's t- test, the Wilcoxon test, one-way analysis of variance, Kruskal-Wallis test, and Mann-Whitney U-test. P < .05 was considered statistically significant. RESULTS: A total of 46 patients were categorized into three facial biotype subgroups with no significant differences among them in age, body mass index, neck circumference, and sex. The respiratory disturbance index (RDI) results were as follows: brachyfacial patients had a reduction to 15 events/h (P < .001), the mesofacial patients had a reduction to 14 events/h (P < .001), and the dolichofacial patients did not show a significant reduction. The oxygen desaturation index (ODI) results were as follows: brachyfacial patients had a reduction in ODI episodes to 45 episodes/h (P = .001), mesofacial patients had a reduction to 18 episodes/h (P = .001). In the brachyfacial group, the number of awakenings with MAD therapy was reduced to 23 events/h (P = .003), while, in the mesofacial group, it was reduced to 37 episodes/h (P = .012). CONCLUSIONS: The facial biotype influences the effectiveness of MAD therapy and is considered a good predictive factor.

Effect of mandibular advancement splint therapy on cardiac autonomic function in obstructive sleep apnoea.

PURPOSE: This study aimed to evaluate the effect of mandibular advancement splint (MAS) therapy on cardiac autonomic function in patients with obstructive sleep apnoea (OSA) using heart rate variability (HRV) analysis. METHODS: Electrocardiograms (ECG) derived from polysomnograms (PSG) of three prospective studies were used to study HRV of patients with OSA before and after MAS treatment. HRV parameters were averaged across the entire ECG signal during N2 sleep using 2-min epochs shifted by 30 s. Paired t-tests were used to compare PSG and HRV measures before and after treatment, and the percent change in HRV measures was regressed on the percent change in apnoea-hypopnea index (AHI). RESULTS: In 101 patients with OSA, 72% were Caucasian, 54% men, the mean age was 56 ± 11 years, BMI 29.8 ± 5.3 kg/m2, and treatment duration was 4.0 ± 3.2 months. After MAS therapy, there was a significant reduction in OSA severity (AHI, - 18 ± 16 events per hour, p < 0.001) and trends towards increased low-frequency to high-frequency ratio, low-frequency power, and reduced high-frequency power (LF:HF, - 0.4 ± 1.5, p = 0.01; LF, - 3 ± 16 nu, p = 0.02, HF, 3.5 ± 13.7 nu, p = 0.01). Change in NN intervals correlated with the change in AHI (ß(SE) = - 2.21 (0.01), t = - 2.85, p = 0.005). No significant changes were observed in the time-domain HRV markers with MAS treatment. CONCLUSION: The study findings suggest that successful MAS treatment correlates with changes in HRV, specifically the lengthening of NN intervals, a marker for improved cardiac autonomic adaptability.

Does oral appliance efficacy in treating obstructive sleep apnea depend on the appliance specialist's experience?

PURPOSE: In France, oral appliances (OAs) are the first-line treatment for moderate and second-line treatment for severe obstructive sleep apnea-hypopnea syndrome. In general, the sleep specialist refers his/her patient to the appliance specialist for the impressions and the fitting. However, is there a relationship between the volume of activity of the appliance specialist and the efficacy of this device? METHODS: Our unit includes seven appliance otolaryngology specialists whose activities are highly variable (number of patients varying by a factor of almost 10). Data from a prospective follow-up registry of patients treated with an OA for moderate and severe obstructive sleep apnea-hypopnea syndrome were studied, and differences in outcomes between practitioners in the team were sought. RESULTS: Among 859 patients, OAs significantly reduced the apnea-hypopnea index. Even if the patients were not completely comparable from one practitioner to another, there was a significant heterogeneity in efficacy (complete or partial response of the apnea-hypopnea index and failure of OAs) between practitioners (p = 0.0038; 0.0011; 0.0007 respectively), with better results in practitioners with a higher level of OA activity. CONCLUSION: The findings suggest that it may be preferable to refer patients to OA practitioners who see a higher volume of patients with moderate or severe obstructive sleep apnea-hypopnea syndrome treated with an OA.