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).

Is significant mandibular advancement possible after the peak of puberty? Dento-osseous palatal expansion and the STM4 technique (Skeletal Therapy Manni Telescopic Herbst 4 miniscrews): A case report.

INTRODUCTION: Treatment of skeletal class II growing patients often requires the use of functional appliances, aimed at promoting mandibular advancement. Among these, Herbst appliance is recommended for its effectiveness, efficiency, and reduced need for compliance. Despite its skeletal favourable effects, well-known dental compensations can occur, especially when the appliance is not used close to the pubertal peak: upper incisors retroclination, lower incisors proclination, upper molars distalization and lower molars mesialization could reduce the overjet needed for a proper mandibular advancement. To counteract these unfavourable effects skeletal anchorage could be crucial. AIM: The aim of this case report is to describe and evaluate the effects of using a skeletally anchored Herbst appliance in an 18-year-old (CVM5) male patient with skeletal Class II malocclusion and a convex profile. TREATMENT PROTOCOL: The treatment started with a tooth-bone-borne palatal expansion, then the upper arch was bonded with pre-adjusted ceramic brackets. After 2months, a Manni Telescopic Herbst (MTH) supported by 4 miniscrews (two in the maxilla and two in the mandible) was applied. To avoid anchorage loss, TADs were connected with elastic chains to the arches. Nine months later, the Herbst was removed, the lower teeth were bonded and the patient wore class 2 elastics to stabilise the occlusion. RESULTS AND CONCLUSIONS: After 24months the treatment goal was achieved with a considerable improvement of the profile and a clinically significant mandibular advancement (Pogonion moved forward 7mm). A one-year follow-up lateral X-rays showed a good stability of the result.

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.

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.

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.

Objectively measured adherence may affect side effects of mandibular advancement therapy in subjects with obstructive sleep apnea.

PURPOSE: The purpose of this study was to determine if objectively measured adherence to oral appliance (OA) treatment may affect dental changes and temporomandibular disorders (TMD) in patients with obstructive sleep apnea (OSA). METHODS: The original study group consisted of adults with OSA who were referred for OA therapy. Eight indicators of subjective side effects of using OA (temporomandibular joint (TMJ) and muscle pain, pain in teeth, jaw stiffness in the morning, clicking, dry mouth, hypersalivation, gingival irritation) were evaluated by a questionnaire. Three occlusal indicators (overjet, overbite, molar occlusion) and clinical TMD signs (TMJ pain, muscle pain, clicking, jaw deviation on opening) were evaluated at baseline and at the 3-, 6-, and 12-month follow-up. In addition, objective adherence monitoring for OA was registered. Statistical analyses included the chi-square test, Fisher's exact test, paired sample t-test, and linear regression analyses. RESULTS: A total of 58 adults with OSA were referred for OA therapy. Mean (SD) age was 50.7 (11.7) and mean apnea-hypopnea index (AHI) was 19.5 (10.0). At 1-year follow-up, the study group consisted of 28 men and 12 women. Overjet but not overbite reduced significantly after 1-year OA therapy. The average nightly wear of OA was related to overjet and overbite reduction, and to TMD signs. Hypersalivation, dry mouth, and tooth discomfort were the most common subjective side effects of OA therapy. CONCLUSION: There was a time-dependent relationship with the nightly wear of OA and reduction in overjet and overbite, and clinical TMD signs. With 60% of mandibular advancement, dental changes and TM-disorders were considered mild/minor in the 1-year study period.

Effect of mandibular advancement appliance use on oral and periodontal health in patients with OSA: a systematic review.

STUDY OBJECTIVES: Use of a mandibular advancement appliance (MAA) is an effective treatment option for mild-to-moderate obstructive sleep apnea (OSA). MAA is well-tolerated but undesirable effects may be observed over time. The present systematic review aimed to assess the effect of MAA use on oral and periodontal health in patients with OSA. METHODS: MEDLINE (PubMed), Cochrane, and Scopus were searched for randomized and non-randomized controlled trials (RCTs, NRCTs), cohorts, and case-control studies reporting on side effects of MAA treatment in OSA patients during a follow-up of at least 6 months. RESULTS: From a total of 169 articles screened, 28 were selected. The most frequently reported MAA-related effects on oral health were: hypersalivation (weighted mean prevalence, 33.3%), occlusal changes (30.2%), muscle pain (22.9%), tooth discomfort or pain (20.2%), and xerostomia (18.3%). No MAA-related periodontal effect was reported. The periodontal status prior to MAA treatment was rarely assessed and described, but 5 studies (17.8%) stated that periodontitis was an exclusion criterion for MAA. Only one retrospective study specifically evaluated periodontal parameters and reported no significant changes in periodontally healthy patients with OSA using MAA for over 7 years. CONCLUSION: MAA use is associated with a number of clinical consequences on oral health, but there is no evidence to conclude whether or not MAA affects periodontal health in patients with OSA. This aspect appears to be under-evaluated and should be further investigated in relation to the type of MAA, the duration of treatment, and prior history of periodontitis.

A systematic review on 4D images of the upper airway in patients with OSA.

AIM-BACKGROUND: In the treatment of obstructive sleep apnoea (OSA), oral appliances are now being recognized as a valuable alternative to continuous positive airway pressure (CPAP). Various static imaging techniques of the upper airways allow for assessment of bone and soft tissue structures. However, static images do not capture dynamic airway characteristics. The aim of this paper was to review 4D imaging techniques in patients with OSA. METHODS: PubMed/MEDLINE, Web of Science and Embase were systematically searched for studies published before June 2022. The review was compliant with the PRISMA guidelines. The quality of each eligible study was critically evaluated by all four authors independently. Four unique articles with qualitative analyses were retrieved. All included studies had a clear objective/aim, an appropriate endpoint and sufficiently described eligibility criteria. RESULTS: With dynamic imaging (4D) evaluation of the upper airway, the incidence of upper airway collapsibility due to use of a mandibular advancement device (MAD) was reduced, extraluminal tissue pressure was decreased and the space in the upper airway was increased, notably in the retropalatal and retroglossal areas of the airway. These findings suggest that MADs may be effective for OSA regardless of whether or not the obstruction site is in the velopharynx or oropharynx. However, further investigation of dynamic changes in the upper airway is required to explain the efficacy of OSA treatment and the underlying mechanisms.

Evaluation of mandibular advancement device placement based on levels of TNF-alpha in participants with obstructive sleep apnea: A clinical study.

STATEMENT OF PROBLEM: Objective assessments of the effect of mandibular advancement device on patients with obstructive sleep apnea are lacking. PURPOSE: The purpose of this clinical study was to compare levels of serum tumor necrosis factor alpha (TNF-alpha), Epworth Sleepiness Scale score, and Berlin Questionnaire score in patients with mild to moderate obstructive sleep apnea before and after treatment with a mandibular advancement device. MATERIAL AND METHODS: Twenty participants diagnosed with mild to moderate obstructive sleep apnea based on polysomnography testing were enrolled. A custom nonadjustable mandibular advancement device with 70% mandibular protrusion was provided for each participant for management of the obstructive sleep apnea. Evaluation of TNF-alpha levels was performed before treatment (baseline) and 3 and 6 months after starting mandibular advancement device therapy by using a Human TNF-alpha enzyme-linked immunoassay (ELISA) sandwich kit. The Epworth Sleepiness Scale and Berlin Questionnaire were also filled out by the participants at the same time intervals (α=.05). RESULTS: A statistically significant decline in the levels of TNF-alpha was observed at 3 and 6 months compared with baseline (P<.001). The Epworth Sleepiness Scale scores showed a statistically significant reduction at 3 and 6 months compared with baseline (P<.001). The risk of obstructive sleep apnea assessed by using the Berlin Questionnaire was found to be significantly reduced at 6 months compared with baseline (P=.001). CONCLUSIONS: Patients with mild to moderate obstructive sleep apnea showed reduced levels of TNF-alpha and Epworth Sleepiness Scale and Berlin Questionnaire scores when treated with a mandibular advancement device.

The Bidirectional Relationship Between Obstructive Sleep Apnea and Chronic Kidney Disease.

Sleep apnea is a condition with significant health risks and increased risk of mortality and is prevalent in patients with chronic kidney disease. This paper describes the detrimental cardiovascular sequelae of sleep-disordered breathing and explores the bidirectional relationship between chronic kidney disease and obstructive sleep apnea. Obstructive sleep apnea-related hypoxia produces a range of harmful systemic effects including oxidative stress, inflammation, and sympathetic activation that collectively worsen the progression of renal disease. In turn, chronic kidney disease can result in increased severity of sleep apnea through inducing (1) uremic neuropathy and myopathy, (2) altered chemosensitivity, and (3) hypervolemia. Continuous positive airway pressure therapy remains the mainstay of treatment for reversing the health risks of apnea. Other strategies aimed at decreasing the high prevalence and associated morbidity of sleep apnea include weight loss, oral appliances, and corrective surgery in the case of airway obstruction.

What Do We Know About Adherence to Oral Appliances?

Long-term effective therapy is essential for obstructive sleep apnea (OSA) control and preventing comorbidity. OSA patients are often reported to be more receptive to oral appliance therapy over positive airway pressure (PAP). Oral appliance usage can now be objectively recorded by temperature microsensors. Studies using commercially available microsensor chips have reported data out to 1 year, with high rates of adherence (>80%), albeit in small samples. There is opportunity to further use this technology to understand individual adherence factors and patterns and in obtaining objective measures of treatment effectiveness, particularly for longer-term health outcomes and allowing comparison to PAP.

[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.

Oral Appliances in the Management of Obstructive Sleep Apnea.

Obstructive sleep apnea (OSA) is a multifactorial condition, and an interdisciplinary approach to diagnosis forms the basis for effective treatment planning. Craniofacial structure and attached soft tissues and muscles play a central role in OSA. Evidence-based studies demonstrate the effectiveness of oral appliances for mandibular advancement and tongue stabilization in managing OSA, and current clinical standards of practice recommend the use of oral appliances to treat OSA when patients cannot tolerate continuous positive airway pressure (CPAP). Although effective, oral appliances are less predictable in managing OSA compared with CPAP therapy. Measures can be taken to improve predictability of oral appliance treatment.

Diagnosis and Management of Obstructive Sleep Apnea: A Review.

Importance: Obstructive sleep apnea (OSA) affects 17% of women and 34% of men in the US and has a similar prevalence in other countries. This review provides an update on the diagnosis and treatment of OSA. Observations: The most common presenting symptom of OSA is excessive sleepiness, although this symptom is reported by as few as 15% to 50% of people with OSA in the general population. OSA is associated with a 2- to 3-fold increased risk of cardiovascular and metabolic disease. In many patients, OSA can be diagnosed with home sleep apnea testing, which has a sensitivity of approximately 80%. Effective treatments include weight loss and exercise, positive airway pressure, oral appliances that hold the jaw forward during sleep, and surgical modification of the pharyngeal soft tissues or facial skeleton to enlarge the upper airway. Hypoglossal nerve stimulation is effective in select patients with a body mass index less than 32. There are currently no effective pharmacological therapies. Treatment with positive airway pressure lowers blood pressure, especially in patients with resistant hypertension; however, randomized clinical trials of OSA treatment have not demonstrated significant benefit on rates of cardiovascular or cerebrovascular events. Conclusions and Relevance: OSA is common and the prevalence is increasing with the increased prevalence of obesity. Daytime sleepiness is among the most common symptoms, but many patients with OSA are asymptomatic. Patients with OSA who are asymptomatic, or whose symptoms are minimally bothersome and pose no apparent risk to driving safety, can be treated with behavioral measures, such as weight loss and exercise. Interventions such as positive airway pressure are recommended for those with excessive sleepiness and resistant hypertension. Managing asymptomatic OSA to reduce cardiovascular and cerebrovascular events is not currently supported by high-quality evidence.

Oral appliance therapy versus nasal continuous positive airway pressure in obstructive sleep apnea: A randomized, placebo-controlled trial on temporomandibular side-effects.

PURPOSE: To assess the differences in the frequency of clinical signs of temporomandibular disorder (TMD) pain and mandibular function impairment between mandibular advancement device (MAD) and nasal continuous positive airway pressure (nCPAP) therapies in obstructive sleep apnea (OSA) patients at baseline and after 6 month of treatment. METHODS: This study concerns a secondary analysis of a randomized placebo-controlled trial in which different treatment effects of an objectively titrated MAD were compared with those of nCPAP and an intra-oral placebo appliance in a parallel design. Sixty-four mild to severe OSA patients (52.0 ± 9.6 years) were randomly assigned to these three groups. All patients underwent a shortened functional examination of their masticatory system at baseline and after 6 months to establish the presence of clinical signs of TMD pain. Mandibular function impairment was assessed with a questionnaire. RESULTS: Clinical signs of TMD pain were only rarely present at baseline and therapy evaluation. No significant differences were found between the three groups in the (low) frequency of clinical signs of TMD pain at both time points (p = .401-.176). In addition, the (low) scores of mandibular function impairment did not differ between the three groups either, neither at baseline (p = .744) nor after 6 months (p = .359). CONCLUSIONS: A low frequency of clinical signs of TMD pain in mild to severe OSA patients was found after 6 months, regardless of treatment with MAD or nCPAP. In addition, no difference in mandibular function impairment was observed between the different treatment modalities.

A stepwise titration protocol for oral appliance therapy in positional obstructive sleep apnea patients: proof of concept.

PURPOSE: In patients with positional obstructive sleep apnea (POSA), oral appliance therapy (OAT) is among the first-line treatments. The aim of this study was to evaluate the effects of a new standardized stepwise titration protocol for OAT in a group of patients with POSA. METHODS: This was an observational intervention trial. Patients who were previously randomized to the OAT intervention arm of a comparison study comprised the subjects for this study. These patients, who had mild to moderate POSA, were assessed after 3 and 12 months for treatment efficacy, objective adherence by temperature microsensor, and side effects. The titration of OAT was performed using a standardized stepwise titration protocol including advancement levels of 60%, 75%, and 90% of the maximum mandibular protrusion. The optimal advancement level per individual was based on a weighted compromise between efficacy and side effects. RESULTS: In total, 36 patients were included and all completed the titration protocol after 3 months. At baseline, the OAT was set at 60% of the maximal mandibular protrusion position. At a 3-month evaluation, the advancement remained at 60% in 16 patients (44%) and reached 75% advancement in 20 patients (56%). Mean apnea-hypopnea index decreased from 12.9 events per hour (9.1-16.7) to 6.9 (3.7-10.3) (P < 0.001), and median objective adherence was 97.4 (61.4-100.00) after 3 months. The 12-month analysis showed consistent results and good OAT tolerance. Six patients (16.7%) terminated OAT and one patient (2.8%) was lost to follow-up. CONCLUSIONS: This standardized stepwise titration protocol for OAT showed good efficacy, good OAT tolerance, and good objective adherence in patients with mild to moderate POSA. Therefore, the protocol is recommended in research projects to improve standardization of methods between studies and in clinical practice for its practical feasibility.

Comparison of treatment outcomes with crowned and banded mandibular anterior repositioning appliance (MARA) in Class II pubertal subjects: A retrospective cohort study.

OBJECTIVE: To compare the skeletal and dentoalveolar changes in Angle Class II malocclusion subjects treated with the banded Mandibular Anterior Repositioning Appliance (Ba-MARA) and crowned MARA (Cr-MARA). MATERIALS AND METHODS: This retrospective cohort study included 40 consecutively treated pubertal adolescents with Class II division 1 malocclusion who received full-fixed orthodontic appliances with a phase of orthopedic treatment using Ba-MARA (n=20) or Cr-MARA (n=20). The samples were compared with 20 untreated Class II controls obtained from the Michigan Growth Study. Lateral cephalograms were obtained pre-treatment (T1), post-MARA removal (T2), and post-full-fixed orthodontic treatment (T3). RESULTS: After MARA removal (T2-T1), the total mandibular length increased only in the Cr-MARA group compared to controls (Co-Gn=5.4mm; post-hoc P=0.042). Overall dentoskeletal changes were less significant during the T3-T2 timepoint. After full-fixed orthodontic treatment (T3-T1), and after controlling for normal growth, both Ba- and Cr-MARA groups increased the total mandibular length by 3.1mm and 3.8mm respectively. Overjet decreased by 2.2mm in Ba-MARA and 2.9mm in Cr-MARA. The mandibular molars erupted and moved mesially in both treatment groups. The mandibular incisors proclined significantly in the Cr-MARA group in comparison to controls (IMPA=7.1o, post-hoc P=0.002). CONCLUSIONS: Both MARA designs were effective in correcting the malocclusion by a combination of small skeletal and dental changes. Although significant differences in dentoskeletal outcomes were observed between the MARA groups and the controls, the differences between the two MARA designs were small and did not achieve statistical/clinical significance.