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Summary Objective To assess three rapid maxillary expansion (RME) appliances in nasal ventilation. Trial design Three-arm parallel randomized clinical trial. Methods Sixty-six growing subjects (10–16 years old) needing RME as part of their orthodontic treatment were randomly allocated (1:1:1 ratio) to three groups of 22 patients receiving Hyrax (H), Hybrid-Hyrax (HH), or Keles keyless expander (K). The primary outcome of nasal ventilation (pressure and velocity) and secondary outcomes (skeletal, dental, soft tissue, and nasal obstruction changes) were blindly assessed on the initial (T0) and final (T1, 6 months at appliance removal) cone-beam computed tomography (CBCT) data by applying computational fluid dynamics (CFD) method. Differences across groups were assessed with crude and adjusted for baseline values and confounders (gender, age, skeletal maturation, expansion amount, mucosal/adenoid hypertrophy, nasal septum deviation) regression models with alpha = 5%. Results Fifty-four patients were analysed (19H, 21HH, 14K). RME reduced both nasal pressure (H: −45.8%, HH: −75.5%, K: −63.2%) and velocity (H: −30%, HH: −58.5%, K: −35%) accompanied with nasal obstruction resolution (H: 26%, HH: 62%, K: 50%). Regressions accounting for baseline severity indicated HH expander performing better in terms of post-expansion maximum velocity (P = 0.03) and nasal obstruction resolution (P = 0.04), which was robust to confounders. Mucosal/adenoid hypertrophy and nasal septum deviation changes were variable, minimal, and similar across groups. The HH resulted in significantly greater increase in the nasal cross-sectional area (62.3%), anterior (14.6%), and posterior (10.5%) nasal widths. Nasal obstruction resolution was more probable among younger (P = 0.04), skeletally immature (P = 0.03), and male patients (P = 0.02) without pre-treatment mucosal hypertrophy (P = 0.04), while HH was associated with marginal greater probability for obstruction resolution. Conclusions RME resulted in improvement of nasal skeletal parameters and simulated ventilation with the former being in favour of the HH and the latter not showing significant differences among the three appliances. Limitation Attrition in the K group due to blocked activation rods possibly leading to limited sample to identify any existing group differences. Harms Replacement of blocked Keles expanders for finalizing treatment. Protocol The protocol was not published before the trial commencement. Registration Australian and New Zealand Clinical Trial Registry; ACTRN12617001136392.

Objectives To assess the potential effects of casein phosphopeptides (CPPs) on orthodontically induced iatrogenic root resorption (OIIRR) and orthodontic teeth movement. Materials and methods Forty Wistar rats (aged 11 weeks) were randomly divided into experimental group (EG; n = 20) that received a diet supplemented with CPP and control group (CG; n = 20) devoid of diet supplement. A 150 g force was applied using nickel titanium (NiTi) coil that was bonded on maxillary incisors and extended unilaterally to a maxillary first molar. At Day 28, animals in both groups were euthanized. Volumetric assessment of root resorption craters and linear measurement of maxillary first molars movement were blindly examined using a micro-computed tomography scan. Results Nine rats were excluded from the experiment due to loss during general anesthesia or appliances' failure. Intra-operator reproducibility was high in both volumetric and linear measurements, 92.8 per cent and 98.5-97.6 per cent, respectively. The results reveal that dietary CPP has statistically insignificant effect on the overall OIIRR and orthodontic movement. Conclusions CPP seems to have statistically insignificant effect on the volume of OIIRR and orthodontic movement in rats. A long-term study with larger sample size using a different concentration of CPP is required to clarify the dentoalveolar effect of CPP.

Aim: The purpose of this study was to assess the difference of removal torque values (RTV) and the bone-to-implant contact (BIC) between the sand-blasted, large grit, and acid-etched (SLA) surface-treated and the machined surface (MA) miniscrews. Material and methods: Miniscrews used in this study were 6mm long with a diameter of 1.5mm. A total of 23 SLA miniscrews and 24 MA miniscrews were placed into the distal femoral condyle of 24 New Zealand rabbits. Removal torque test and the BIC was histologically evaluated at 0 and 8 weeks. Results: There was no statistical difference between the RTV in the MA group versus the SLA group at both 0 and 8 weeks. Comparing 0–8 weeks, there was no significant difference in RTV of the SLA group ( P = 0.48), however the change in the MA group was statistically significant ( P = 0.006). Histological observation showed a significant decrease in BIC comparing 0 and 8 weeks for the MA group. The BIC ratio at 8 weeks was statistically significantly higher in the SLA group compared to the MA group. Conclusion: SLA surface preparation does not increase the RTV of miniscrews. Further investigations under loading and a large sample size are required.

STUDY OBJECTIVES Oral appliances are increasingly being used for treatment of obstructive sleep apnea (OSA). Mandibular advancement splint (MAS) mechanically protrudes the mandible, while the tongue stabilizing device (TSD) protrudes and holds the tongue using suction. Although both appliances can significantly improve or ameliorate OSA, their comparative effects on upper airway structure have not been investigated. DESIGN Cohort study. SETTING Sleep Investigation Unit. PATIENTS 39 patients undergoing oral appliance treatment for OSA. INTERVENTIONS OSA patients underwent magnetic resonance imaging (MRI) of the upper airway during wakefulness at baseline and with MAS and TSD in randomized order. Treatment efficacy was determined by polysomnography in a subset of 18 patients. MEASUREMENTS AND RESULTS Upper airway lumen and surrounding soft tissue structures were segmented using image analysis software. Upper airway dimensions and soft tissue centroid movements were determined. Both appliances altered upper airway geometry, associated with movement of the parapharyngeal fat pads away from the airway. TSD increased velopharyngeal lateral diameter to a greater extent (+0.35 ± 0.07 vs. +0.18 ± 0.05 cm; P

OBSTRUCTIVE SLEEP APNEA (OSA) IS A COMPLEX MULTIFACTORIAL CONDITION PRODUCED BY A COMBINATION OF ANATOMIC AND PHYSIOLOGICAL FACTORS.1 It is characterized by repetitive complete or partial closure of the upper airway during sleep resulting in sleep fragmentation and oxygen desaturation.2,3 Numerous risk factors including male gender and obesity,4 ethnicity,5 and craniofacial structure6 have been identified as increasing susceptibility to this disease. OSA has a significant associated morbidity and mortality and has been linked to cardiovascular7,8 and cerebrovascular disease,9,10 excessive daytime sleepiness,11 and increased risk for motor vehicle accidents.12–14 The prevalence of OSA varies depending on diagnostic criteria and population studied, and has been reported as affecting 4% of men and 2% of women in the middle-aged workforce.15 It was also found that among adults aged 30-69 years, 17% of adults had mild or worse sleep disordered breathing (AHI ≥ 5), and 5.7% of adults had moderate or worse sleep disordered breathing.16 As such, OSA is recognized as a significant public health issue. While the gold standard of care combines conservative modalities such as weight loss and nasal continuous positive airway pressure (CPAP),17 interest in oral devices has been increasing possibly because of compliance difficulties with CPAP. Mandibular advancement splints (MAS) are the most common type of oral device; they protrude the mandible during sleep, thereby having a favorable impact on upper airway structure and function. Several designs have been extensively investigated and shown to be efficacious in a substantial number of patients, particularly those with mild to moderate OSA.18–21 The American Academy of Sleep Medicine practice parameters recommend the use of MAS as an alternative to CPAP for patients who prefer oral appliances or refuse or are unable to tolerate CPAP, particularly in mild to moderate OSA.22 A tongue stabilizing device (TSD) is a preformed appliance and uses suction to protrude the tongue and improve upper airway structure and function. The earlier designs were similar to a mouthguard, covering the upper and lower teeth to assist retention, with a flexible bulb into which the tongue was protruded.23 The current design has no dental coverage, reduced bulk, and has the bulb being retained in place only by suction. There are currently only limited data on the efficacy of the current device, which is commercially available.24 As they are not reliant on the teeth for retention, TSD have been proposed as an option for patients with a reduced number or absence of teeth (hypodontia, edentulism), or compromised dental health (periodontal disease). The aim of this study was to compare the efficacy of these 2 types of oral devices in typical OSA patients.

Background: Although Rapid Maxillary Expansion (RME) has been used for over a century, its effect on upper airways has not yet adequately been assessed in an evidence-based manner. Objective: To investigate the volumetric changes in the upper airway spaces following RME in growing subjects by means of acoustic rhinometry, three-dimensional radiography and digital photogrammetry. Search methods: Literature search of electronic databases and additional manual searches up to February 2016. Selection criteria: Randomized clinical trials, prospective or retrospective controlled clinical trials and cohort clinical studies of at least eight patients, where the RME appliance was left in place for retention, and a maximum follow-up of 8 months post-expansion. Data collection and analysis: After duplicate data extraction and assessment of the risk of bias, the mean differences and 95 per cent confidence intervals (CIs) of upper airway volume changes were calculated with random-effects meta-analyses, followed by subgroup analyses, meta-regressions, and sensitivity analyses. Results: Twenty studies were eligible for qualitative synthesis, of which 17 (3 controlled clinical studies and 14 cohort studies) were used in quantitative analysis. As far as total airway volume is concerned patients treated with RME showed a significant increase post-expansion (5 studies; increase from baseline: 1218.3mm3; 95 per cent CI: 702.0 to 1734.6mm3), which did not seem to considerably diminish after the retention period (11 studies; increase from baseline: 1143.9mm3; 95 per cent CI: 696.9 to 1590.9mm3). Limitations: However, the overall quality of evidence was judged as very low, due to methodological limitations of the included studies, absence of untreated control groups, and inconsistency among studies. Conclusions: RME seems to be associated with an increase in the nasal cavity volume in the short and in the long term. However, additional well-conducted prospective controlled clinical studies are needed to confirm the present findings. Registration: None. Funding: Australian Society of Orthodontics Foundation for Research and Education Inc.