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Objective: The aim of this study was to investigate the effects of exercise and mandibular advancement device (MAD) on severity of Obstructive sleep apnea syndrome (OSAS) with mandibular retrognathia., Methods: Patients were randomly allocated into either exercise group or MAD group. All patients underwent blood tests, polysomnography studies and questionnaires studies at enrollment and at the 12-week's follow-up., Results: Our study showed MAD was superior to exercise in improving polysomnographic outcomes and Snore Scale (SS) score. No significant difference was observed between the two treatments in terms of Epworth Sleepiness Scale (ESS) score. Moreover, in the exercise group, improvements were also observed in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C)., Conclusion: MAD was more effective than exercise in improving sleep efficiency. Exercise can improve daytime sleepiness and lipid metabolism, independent of the effects on BMI. Trial registration ChiCTR2000034188.

To investigate the effect of bimaxillary surgery on the stress distribution of the temporomandibular joint (TMJ) in patients with mandibular retrognathia under unilateral molar clenching (UMC). Five patients with mandibular retrognathia (preoperative group) and ten asymptomatic subjects (control group) were recruited. In addition, patients treated with bimaxillary surgery were considered as the postoperative group. The muscle forces corresponding to UMC were applied. The results showed that the discal stresses in the postoperative group were significantly greater than those in the preoperative and control groups. Bimaxillary surgery plus UMC had a detrimental effect on the TMJ.

Objective The study was focused on evaluating the change in mandibular morphology following the Twin Block appliance therapy and recording its effect on the maxilla and maxillary dentoalveolar complex. Also, the results of the Twin Block appliance between males and females were compared.  Material and methods In this two-armed retrospective cephalometric study, 30 patients (mean age 12 years) treated with Twin Block appliance for the period of 8-12 months were chosen, and their records were obtained to analyze. These results were compared with 15 control subjects of the same age group chosen from the American Association of Orthodontics Foundation (AAOF) growth legacy collection: Michigan Growth Study Class II subjects. Cephalometric tracing was done, and data was processed for descriptive statistical analysis. Results Paired sample t-test and ANOVA test were performed to evaluate the differences in the pre-treatment (T1) and post-functional (T2) values. ∠ANB showed a mean difference of -4.71°±1.55° for males and 6.22°±6.78° for females, which is significant. The mandibular length (Co-Gn), for male subjects, the mean difference was 5.14±1.74 mm, and for female subjects, it was 6±2mm, which is highly significant; 49.88% of skeletal changes and 50.12% of dentoalveolar changes were reported to bring about Class II correction with Twin Block. Conclusion A successful increase in mandibular length was achieved using a Twin Block as a functional appliance. Also, the significant maxillary restraining effect was recorded. More skeletal changes were observed in males than females., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Gandhi et al.)

Introduction: The human upper airway regulates temperature, but its heating capacity remains unclear when the ambient temperature is low and the airway structure is abnormal. Therefore, the purpose of this study was to evaluate the heat transfer characteristics of the upper airway in patients with mandibular retrognathia, and to quantitatively evaluate the influence of ambient temperature on the temperature field of the upper airway, which could provide a valuable reference for the prediction, diagnosis and treatment of respiratory tract related diseases., Methods: Two typical ambient temperatures of -10 °C and 20 °C were selected to numerically simulate the air flow and heat transfer synchronization in the upper airway model of mandibular retrognathia under quiet breathing and heavy breathing., Results and Discussion: The results showed that the inspired air could not be sufficiently heated after flowing through the upper airway and main trachea in the two breathing states under low temperature conditions, and the inferior bronchus was more stimulated under the state of heavy breathing. In addition, the vortex flow structure in the upper airway can enhance the convective heat transfer effect in the corresponding area., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Gao, Liu, Liu and Zhang.)

Objective: To evaluate whether there is a difference between the effects of Bionator and Forsus appliances on airway volume., Methods: Forty patients with mandibular retrognathia were divided into two groups. The Bionator appliance was applied to Group 1, while the Forsus FRD EZ2 appliance was applied to Group 2. Three-dimensional images were captured before and after functional appliance use in both groups. Dolphin 3D software was used for airway measurements., Results: No statistically significant difference was found between the groups in terms of volumetric and area measurements. There was a statistically significant difference between the minimum axial T and O-N border T measurements of the groups., Conclusion: The use of functional appliances may contribute to an increase in oropharyngeal airway dimensions, but there was no difference between the Bionator and Forsus groups in terms of volumetric measurements.

The Tübingen Palatal Plate (TPP) is a minimally invasive yet highly effective functional orthodontic treatment for upper airway obstruction in infants with Robin Sequence (RS). It consists of a palatal plate to cover the cleft and a velar extension that shifts the root of the tongue forward. We review our practical experience with this approach. First, upon admission, our local orthodontists perform an (3-D) intraoral scan of the maxilla. Based on the scan data, the TPP is manufactured in a semi-digital workflow. The length and angulation of its extension is checked via awake laryngoscopy and the effectiveness confirmed by a sleep study. Plates are kept in place by adhesive cream. When inserting the TPP, the tip of the tongue must be visible. Next, metal fixation bows should be secured to the forehead using tape and elastic bands. Plates are removed daily for cleaning, and the oral mucosa is then checked for pressure marks. Feeding training (initially only via finger feeding) may even start before plate insertion. Breathing often normalizes immediately once the plate is inserted. For isolated RS, we have never had to perform a tracheostomy. This has largely been possible through our highly dedicated and competent team, particularly the nursing staff, and the early involvement of parents.

Background: The present study analyzed the changes obtained on the upper airway and hyoid bone dimensions in a group of patients with skeletal Class II malocclusion treated with functional elastodontic devices compared to an untreated control group., Methods: A group of 33 patients (19 females and 14 males) with Class II malocclusion treated with AMCOP ® SC elastodontic device was compared with a control group of 35 subjects (17 females and 18 males) with untreated Class II malocclusion. Lateral cephalograms were available at the start (T0) and end of treatment/period of observation (T1). Cephalometric analysis was performed and linear measurements to evaluate airway space and hyoid bone position were also obtained. A multivariate analysis of variance for repeated measures (MANOVA) was performed to determine the effects of interactions for the groups for time., Results: Statistically significant differences were found in the study group from T0 and T1 with an improvement of superior upper airway (SPAS p < 0.0001), while in the control group it did not change in a statistically significant way from T0 to T1. The MANOVA test showed statistically significant differences between the two groups for the changes of SPAS ( p = 0.003), IAS ( p = 0.049), and H-C3 vertical ( p = 0.038) values., Conclusions: Functional elastodontic therapy produced significant favorable airway changes in skeletal class II subjects.

Background: To assess the long-term functional orthodontic outcome of the Tübingen palatal plate (TPP) in children with Robin sequence (RS) in comparison to age- and sex-matched healthy controls., Methods: Between 09/2019 and 10/2020, we performed orthodontic assessments in 41 children at our Department of Orthodontics. Included were patients with RS (17 non-syndromic; four syndromic) and healthy controls ( n = 22, average age in both groups 9.9 y). Facial analyses of 2D images, digital study casts and cephalometric measurements were made., Results: The orthodontic examinations showed no statistically significant group differences regarding functional extraoral, intraoral and pharyngeal parameters, or in skeletal patterns. The relationship between the upper and lower incisors was significantly increased (overjet 4 (2-10) vs. 3 (0-9) mm; p = 0.01) with a significant deficit in the lower face proportions (Jaw Index 4.15 (1.9-9.6) vs. 2.98 (0-9); p = 0.02; Facial convexity angle 157 (149-173) vs. 159 (149-170); p = 0.01)., Conclusion: Children with RS treated with the TPP showed normal long-term functional orthodontic outcomes, thanks to the functional adaption of the stomatognathic system. However, soft tissue growth did not completely match skeletal growth, resulting in a more convex facial profile.

Aim: Some obstructive sleep apnea (OSA) patients may have mandibular retrognathia (ANB > 4.7° and SNB < 76.2°). Currently, there are no studies that have compared the effectiveness of continuous positive airway pressure (CPAP) versus mandibular advancement device (MAD) in severe OSA patients with mandibular retrognathia. We explored the efficacy of CPAP versus MAD for the treatment of severe OSA patients with mandibular retrognathia., Methods: A total of 105 patients were enrolled. Outcomes were assessed by using polysomnography, Epworth Sleepiness Scale (ESS), Snore Scale (SS), Self-rating Anxiety Scale (SAS), and compliance, before treatment and after 6 and 12 months of treatment., Results: Continuous positive airway pressure was superior to MAD in improving polysomnographic outcomes and SS score, but reported compliance was higher on MAD. There is no significant difference between the 2 treatments in terms of ESS score and SAS score. Obstructive sleep apnea patients with mandibular retrognathia showed greater improvement than those without mandibular retrognathia in terms of apnea-hypopnea index and oxygen desaturation index after MAD., Conclusion: Continuous positive airway pressure and MAD are both effective in treating severe OSA patients with mandibular retrognathia. Mandibular advancement device is a good alternative to CPAP in severe OSA patients with mandibular retrognathia. Mandibular advancement device is more effective in treating OSA patients with mandibular retrognathia than those without. Trial registration: ChiCTR2000032541.

Background: The Advanced Mandibular Spring (AMS) was newly developed as a dentofacial orthopedic appliance in conjunctive use of clear aligners to treat Class II malocclusion with mandibular retrognathia in adolescents. This study aimed to launch a biomechanical assessment and evaluate whether the stress patterns generated by AMS promote mandibular growth., Methods: A three-dimensional finite element model was constructed using images of CBCT and spiral CT. The model consisted of craniomaxillofacial bones, articular discs, retrodiscal elastic stratum, masticatory muscle, teeth, periodontal ligament, aligner and AMS. Mechanical effects were analyzed in three types of models: mandibular postural position, mandibular advancement with AMS, and mandibular advancement with only muscular force., Results: The stress generated by AMS was distributed to all teeth and periodontal ligament, pushing mandibular teeth forward and maxillary teeth backward. In the temporomandibular joint area, the pressure in the superior and posterior aspects of the condyle was reduced, which conformed to the stress pattern promoting condylar and mandibular growth. Stress distribution became even in the anterior aspect of the condyle and the articular disc. Significant tensile stress was generated in the posterior aspect of the glenoid fossa, which conformed to the stress pattern stimulating the remodeling of the fossa., Conclusions: AMS created a favorable biomechanical environment for treating mandibular retrognathia in adolescents., (© 2022. The Author(s).)

Purpose: The aim of this study was to compare the effects of two different mandibular advancement methods on skeletal, dentoalveolar, and soft tissue structures through cephalometric measurements., Materials and Methods: The aim of this study was to compare the effects of two different mandibular advancement methods on skeletal, dentoalveolar, and soft tissue structures through cephalometric measurements., Results: The mandibular base was observed to move forward significantly in both groups (p<0.05). However, the forward movement of the mandibular base was greater in the TB group than in the EA group (p<0.05). There was no difference in lower incisor protrusion between the two treatment methods. The EA device was found to cause a significant increase in vertical direction parameters (p<0.05)., Conclusion: Both methods resulted in Class II malocclusion correction as well as an acceptable occlusion plus profile. The effects of EA were primarily dentoalveolar. In patients with high aesthetic expectations, EA could be an alternative for TB., (Copyright © 2022 European Oral Research.)

This article describes a case report of the patient with mandibular retrognathia, class II malocclusion, constriction and deformation of dental arches and bimaxillary protrusion. Due to the patient's refuse to undergo the orthognathic surgery, after diagnostic, it was decided to carry out the orthodontic dentoalveolar compensation. The combined use of the functional fixed telescopic appliance (FFTA), bracket system and orthodontic miniscrews made it possible to effectively normalize the mandibular position, achieve orthognathic occlusion, eliminate bimaxillary protrusion and improve the face profile. This method significantly reduced invasiveness and time of orthodontic treatment.

Objective: To analyse oral health related quality of life (OHRQoL) several years after orthognathic treatment in patients who had Class II malocclusion with retrognathic mandible. Material and methods: The initial study cohort comprised 151 patients with orthognathic treatment in 2007-2011. Of them, 77 patients (Group 1, mean age 41 years, range 19-71 years, 71% women) were clinically examined 6 years (range 4-8 years) after bilateral sagittal split osteotomy (BSSO). Group 2 included 24 former patients (mean 48 years, range 25-79 years, 50% women) who were willing to participate in a structured telephone interview. Group 3 consisted of 22 prospective patients (mean 35 years, range 18-56 years, 86% women) with a recent orthognathic treatment plan and awaiting treatment. QoL was assessed using two questionnaires, OHIP-14 and OQLQ. Results: Based on responses, patients who had received orthognathic treatment (Groups 1 and 2) had better QoL than those awaiting treatment (Group 3). Conclusion: Conventional orthognathic treatment, including mandibular advancement with BSSO, seems to have a positive long-term effect on patients' QoL. More long-term follow-up studies are needed to assess the real impact of treatment on patients' lives in the long run.

Background: Pediatric obstructive sleep apnea/hypopnea syndrome (OSAHS) is a multifactorial syndrome caused by many risk factors, such as craniofacial anomalies, adenotonsillar hypertrophy, obesity, and airway inflammation. Although new treatment patterns have recently been proposed, treatment methods for children remain particularly challenging and controversial. This randomized controlled trial was designed to investigate the efficacy of adenotonsillectomy and/or orthodontic treatment for children who have mild OSAHS with mandibular retrognathia., Methods: A sample of 352 children with mild OSAHS and mandibular retrognathia, who are aged between 7 and 10 years, will be enrolled in the study. They will be randomized into four groups: the drug treatment group, the surgical treatment group, the orthodontic treatment group, or the surgery and postoperative orthodontic group. After randomization the children will receive treatments within 4 weeks. Outcome assessment will take place at the following points: (1) baseline, (2) 7 months after the treatment starting point, (3) 12 months after the treatment starting point, and (4) 24 months after the treatment starting point. The primary endpoint of the trial is the mean change in obstructive apnea/hypopnea index. Other endpoints will consist of the lowest oxygen saturation, apnea index, and hypopnea index assessed by polysomnography, subjective symptoms (assessed by the OSA-20 questionnaire), cephalometric measurements, and morphologic analysis of the upper airway., Discussion: The results of this study will provide valuable evidence for the merits and long-term efficacy of different treatment approaches and contribute to facilitating the multidisciplinary treatment of pediatric OSAHS., Trial Registration: ClinicalTrials.gov : NCT03451318. Registered on 2 March 2018 (last update posted 19 April 2018).

Objective: To compare cephalometric changes of pharyngeal structures after rapid palatal expansion (RPE) with those induced by a twin block mandibular advancement device (MAD) with palatal expansion capability. Methods: This retrospective study investigated 55 Class II pediatric patients, divided into two groups: 29 patients treated with RPE and 26 patients treated with MAD. Lateral cephalometric measurements were compared before and after treatment. Results: Changes in pharyngeal airway space were statistically significant in both groups ( p  < 0.001) from a pre-treatment mean distance measured between the lower posterior pharyngeal wall and the hyoid bone (LPF-H) of 25.42 mm in the MAD group and 28.62 mm in the RPE group, to a post-treatment mean LPF-H of 27.96 mm in the MAD group and 31.52 mm in the RPE group. Conclusion: Significant changes in pharyngeal space may be obtained in Class II patients through both rapid palatal expansion and mandibular advancement devices with palatal expansion capability.

A randomized clinical trial was conducted to compare bilateral sagittal split osteotomy (BSSO) with distraction osteogenesis (DO) for the advancement of the mandible, with a focus on patient discomfort, postoperative pain, the need for analgesics, and occurrence of infection. All patients were non-syndromal, had a class II hypoplastic mandible, and had not undergone previous mandibular surgery. A total of 66 patients were allocated randomly to the BSSO group (32 patients) or the DO group (34 patients). Sixty-three patients were eligible for evaluation, 29 in the BSSO group and 34 in the DO group. Patients in the DO group experienced more pain after 6 days postoperative, and were administered more analgesics after 5 days postoperative than patients in the BSSO group (P=0.030 and P=0.045, respectively). The operating time was significantly shorter for the BSSO group than for the DO group (78 min vs. 100 min, P=0.024). All postoperative infections (12 in total) emerged in the DO group (P=0.005). All patients in the DO group had a second surgery in day care to remove the distractor, while two patients in the BSSO group needed plate removal. It is concluded that patients experienced more pain after DO, needed more analgesics postoperatively, and had more infections in comparison to the BSSO group., (Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

A randomized clinical trial was carried out to evaluate postoperative stability after mandibular advancements in non-syndromal class II patients with a bilateral sagittal split osteotomy (BSSO) or distraction osteogenesis (DO). In total 32 patients could be included in the BSSO group and 34 patients in the DO group. The BSSO was converted to a unilateral procedure for one patient, and two patients in the BSSO group were lost during follow-up. A total 63 patients could be evaluated, 29 in the BSSO group and 34 in the DO group. Advancement was comparable in the two groups (mean 7.2mm). The mean follow-up period was 23.8 months (range 11-50 months). Lateral cephalograms were hand-traced. Horizontal relapse was measured in Y-B (mm) and SNB (°). For DO this was -0.324 mm and -0.250°, and for BSSO this was -0.448 mm and -0.259°, respectively (both not significant; NS). Vertical relapse measured in X-B was -0.074 mm for DO and -0.034 mm for BSSO (NS). The magnitude of advancement, a high mandibular plane angle, age and gender were not identified as independent risk factors for relapse. In conclusion, a BSSO and DO gave both similar stable results in advancements of the mandible up to 10mm., (Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

A randomized clinical trial was performed to evaluate differences in postoperative neurosensory disturbance (NSD) between two methods of mandibular advancement surgery. A total of 66 non-syndromal class II patients with mandibular hypoplasia were randomized for either distraction osteogenesis (DO) or bilateral sagittal split osteotomy (BSSO). Twenty-nine patients in the BSSO group and 34 patients in the DO group were available for evaluation. Objective assessment was performed by Semmes-Weinstein (SW) monofilament testing preoperatively and at least 1 year after surgery. Six of the 34 patients (17.6%) in the DO group experienced objective NSD, compared to 5/29 patients (17.2%) in the BSSO group. In the evaluation of nerve function by individual nerves, 8/68 nerves (11.8%) revealed objective NSD in the DO group, compared to 7/58 nerves (12.1%) in the BSSO group. A subjective NSD was reported in 11/34 patients (32.4%) in the DO group, compared to 9/29 patients (31.0%) in the BSSO group. In the evaluation of nerve function by individual nerves, a subjective NSD was reported for 13/68 nerves (19.1%) in the DO group, compared to 13/58 nerves (22.4%) in the BSSO group. None of the differences was significant. No differences in neurosensory disturbance could be found between the two study groups. Objective WS monofilament testing appeared to underestimate NSD compared to subjective patient report., (Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The aim of this prospective clinical study was to evaluate the short-term and long-term skeletal and dental changes after mandibular osteodistraction with tooth-borne appliances in adult orthodontic patients. The sample consisted of 10 non-growing Caucasian patients with a Class II skeletal relationship due to mandibular deficiency, together with Class II dental malocclusion. All patients underwent mandibular distraction osteogenesis (MDO) using the ROD1 tooth-borne device. Lateral cephalograms were evaluated at four time intervals: pretreatment (T1), after mandibular distraction (T2), after orthodontic fixed appliance therapy (T3), and at long-term observation 8-year post-distraction (T4). Statistical analyses compared the skeletal and dental changes in intervals T1-T2, T2-T3, T3-T4, T1-T4, and T2-T4. MDO with the ROD1 tooth-borne device produced significant long-term (T1-T4) increases in the SNB angle (2.3°), total mandibular length (5.9mm), and corpus length (4.5mm). Potential adverse sequelae included significant increases in mandibular plane angle (4.3°), lower anterior dental height (2.8mm), and lower posterior dental height (2.5mm). Significant increases in lower incisor proclination occurred during distraction (7.5°). Distraction osteogenesis with tooth-borne appliances offers a minimally invasive surgical method with stable results for correcting mandibular deficiency in non-growing patients., (Copyright © 2013 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

This article evaluates the use of distraction osteogenesis in the treatment of mandibular retrognathia and laterognathia and the long term treatment results of the patients treated with this technique. The procedure was carried out in 5 subjects (3 males and 2 females, mean age 18.4 years) aged between 14 years and 27 years. In patients treated with bilateral mandibular distraction, it was observed that the ANB angle decreased by a mean of 5 degrees , the mandibular corpus length increased by a mean of 14.5 mm and the overjet decreased by a mean of 12.2 mm after treatment. In patients treated with unilateral mandibular distraction, a mean of 3.5 degrees reduction was achieved in ANB angle, the mandibular corpus length increased by a mean of 5.5 mm and a mean of 7 mm correction was achieved in relation to craniofacial midline with treatment. One of these patients showed an increase of 10 mm in ramus height on the affected side and a decrease of 5 degrees in gonial angle whereas the other one showed an increase of 12.5 degrees in gonial angle and an increase of 11 mm in ramus height on the affected side after treatment. The most significant long term relapse was observed in one of the patients treated with bilateral mandibular distraction. Long term relapse seen in the rest of the patients was within clinically acceptable limits. It can be concluded that distraction of the deformed mandible is a feasible and effective technique for treating mandibular retrognathia and laterognathia. However, it must be borne in mind that accurate placement of the distractors and determining the correct distraction vector are crucial factors that have an influence on long term clinical success.