The Health Effects of 72 Hours of Simulated Wind Turbine Infrasound: A Double-Blind Randomized Crossover Study in Noise-Sensitive, Healthy Adults.

BACKGROUND: Large electricity-generating wind turbines emit both audible sound and inaudible infrasound at very low frequencies that are outside of the normal human range of hearing. Sufferers of wind turbine syndrome (WTS) have attributed their ill-health and particularly their sleep disturbance to the signature pattern of infrasound. Critics have argued that these symptoms are psychological in origin and are attributable to nocebo effects. OBJECTIVES: We aimed to test the effects of 72 h of infrasound (1.6-20 Hz at a sound level of ∼90 dB pk re 20µPa, simulating a wind turbine infrasound signature) exposure on human physiology, particularly sleep. METHODS: We conducted a randomized double-blind triple-arm crossover laboratory-based study of 72 h exposure with a >10-d washout conducted in a noise-insulated sleep laboratory in the style of a studio apartment. The exposures were infrasound (∼90 dB pk), sham infrasound (same speakers not generating infrasound), and traffic noise exposure [active control; at a sound pressure level of 40-50 dB LAeq,night and 70 dB LAFmax transient maxima, night (2200 to 0700 hours)]. The following physiological and psychological measures and systems were tested for their sensitivity to infrasound: wake after sleep onset (WASO; primary outcome) and other measures of sleep physiology, wake electroencephalography, WTS symptoms, cardiovascular physiology, and neurobehavioral performance. RESULTS: We randomized 37 noise-sensitive but otherwise healthy adults (18-72 years of age; 51% female) into the study before a COVID19-related public health order forced the study to close. WASO was not affected by infrasound compared with sham infrasound (-1.36 min; 95% CI: -6.60, 3.88, p=0.60) but was worsened by the active control traffic exposure compared with sham by 6.07 min (95% CI: 0.75, 11.39, p=0.02). Infrasound did not worsen any subjective or objective measures used. DISCUSSION: Our findings did not support the idea that infrasound causes WTS. High level, but inaudible, infrasound did not appear to perturb any physiological or psychological measure tested in these study participants. https://doi.org/10.1289/EHP10757.

Developing pediatric three-dimensional upper airway normative values using fixed and interactive thresholds.

OBJECTIVE: To develop and compare pediatric upper airway three-dimensional normative values using the two most commonly used cone beam computed tomography (CBCT) software: Invivo5 (fixed threshold) and Dolphin 3D (interactive threshold). STUDY DESIGN: Out of 3738 CBCT scans, scans of 81 pediatric patients were utilized after applying strict exclusion criteria. The sample was grouped into two age groups (7-11 and 12-17 years). Intra-class correlation coefficient was used to test intra-rater and inter-rater reliability and showed coefficients greater than 0.9 indicating good reliability of the methods used. RESULTS: Paired t tests showed that volumetric and area measurements obtained using Dolphin 3D were significantly larger than those obtained using Invivo5 (p < 0.05). The mean minimal cross-sectional areas (MCSA) for Dolphin 3D were 151 mm2 and 177 mm2 for age groups 1 and 2, respectively. The mean MCSA values for Invivo5 for age groups 1 and 2 were 120 mm2 and 145 mm2, respectively. CONCLUSION: Pediatric upper airway volumetric, area, and linear measurements were reported after applying strict exclusion criteria including a validated sleep questionnaire. Our goal is that clinicians utilize the proposed-here normative values for screening and assist in the timely diagnosis and management of pediatric sleep apnea.

Changes in sleep and airway variables in patients with obstructive sleep apnea after mandibular advancement splint treatment.

INTRODUCTION: Obstructive sleep apnea (OSA) is an extensive public health problem that imposes considerable morbidity. Mandibular advancement splint (MAS) therapy is a well tolerated treatment, but success rates are difficult to predict. Our objective was to investigate the relationship of oropharyngeal airway dimensions, sleep characteristics, patient biometrics, and treatment response within an OSA patient sample. METHODS: Records of 33 adults were assessed retrospectively with the use of Dolphin 3D and Image J to measure the airway on pretreatment supine cone-beam computed tomography images and derived lateral cephalograms. The patients used Somnodent (Somnomed; Crows Nest, Australia) MAS appliances, which were titrated over 6-8 weeks. Appliance titration measurements and pre- and posttreatment polysomnograms were assessed. Respiratory disturbance index (RDI), absolute and percentage changes in RDI, non-rapid eye movement (NREM) RDI, rapid eye movement (REM) RDI, supine and nonsupine NREM and REM RDI, and minimal blood-oxygen saturation variables were evaluated. The associations of measurements from 2D and 3D minimal anterior-posterior linear distance and 3D airway variables with MAS treatment response were estimated. RESULTS AND CONCLUSIONS: Combined effects of baseline total airway volume, body mass index, neck circumference, location of minimal cross sectional area, and OSA severity were associated with treatment response. Patients with higher initial OSA and more superiorly located airway constriction showed enhanced treatment response to MAS therapy. Airway constriction due to maxillofacial disproportions rather than soft tissue obstruction also showed better treatment response. No significant relationships were found in lateral cephalogram measurements.

Long-term effects of various cleaning methods on polypropylene/ethylene copolymer retainer material.

OBJECTIVES: To evaluate long-term light transmittance, surface roughness, and flexural modulus of polypropylene/ethylene copolymer retainer material after exposure to different cleaning methods. MATERIALS AND METHODS: Standardized polypropylene/ethylene copolymer retainer specimens (n = 70, 50.8 mm × 12.7 mm × 1.0 mm) were subjected to seven chemical cleaning solutions: Invisalign cleaning crystals, Retainer Brite, Polident, Listerine mouthwash, 2.5% acetic acid, 0.6% NaClO, and 3% H2O2 for 6 months. The specimens were exposed to the different solutions twice a week for 15 minutes or according to manufacturer's instructions, then stored in artificial saliva at 37°C. Another group of specimens (n = 10) were brushed with a standardized toothbrushing machine for 2 minutes twice a week. At baseline and 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified using spectrophotometry, profilometry and three-point bend testing, respectively. Qualitative analysis was performed using a scanning electron microscope (SEM). Statistical analyses were performed at a significance level of .05. RESULTS: The results showed that light transmittance decreased significantly from baseline for all cleaning methods at 6 months. For an individual method, no significant differences were observed between specimens at baseline and 6 months in surface roughness and flexural modulus. No discernible differences in surface features were observed on SEM images. CONCLUSIONS: The results indicate that different cleaning methods affect the long-term light transmittance of the studied polypropylene/ethylene copolymer retainer material. However, for an individual cleaning method, no significant differences were shown for surface roughness or flexural modulus values at 6-months compared to baseline.

Biochemical markers of cardiac dysfunction in children with obstructive sleep apnoea (OSA).

OBJECTIVES: We explored relationships between biochemical markers and cardiac responses of children with and without obstructive sleep apnoea (OSA) during exercise. We hypothesised that serum markers of sympathetic nervous system activity and low-grade inflammation would correlate with cardiac responses to exercise in children with or without OSA. METHODOLOGY: The study included 40 of 71 children with previously characterised responses to cardiopulmonary exercise testing. Measures included serum cytokine levels using a multiplex bead-based assay (interleukins IL-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α and IFN-γ). Serum amyloid A (SAA) was quantified by nephelometry, and metanephrine/normetanephrine levels were measured by liquid chromatography, mass-spectroscopy. Comparisons were made between children with and without OSA, and with and without obesity. Relationships between biomarkers and various cardiac parameters were explored by linear regression. RESULTS: Amongst the 40 children in this study, OSA was present in 23. Compared to the 17 children without OSA, those with OSA had higher resting serum IL-6 levels compared to those without (median 3.22 pg/ml vs. 2.31, p < 0.05). Regarding correlations with cardiac function after adjusting for OSA, IL-8 negatively correlated to heart rate (HR) response following exercise (p = 0.03) and IFN-γ negatively correlated with Stroke Volume Index (SVI) (p = 0.03). Both metanephrine and normetanephrine levels positively correlated with SVI (p = 0.04, p = 0.047; respectively) and QI (p = 0.04, p = 0.04; respectively) during exercise when adjusting for OSA. CONCLUSIONS: Children with OSA have raised morning levels of serum IL-6. Separately, higher levels of IFN-γ and IL-8 and lower levels of metanephrine and normetanephrine related to poorer cardiac function during exercise.

Long-term effects of different cleaning methods on copolyester retainer properties.

OBJECTIVE: To evaluate light transmittance, surface roughness, and flexural modulus of copolyester retainer material after long-term exposure to different cleaning methods. MATERIALS AND METHODS: Standardized copolyester retainer specimens (ACE) were subjected to seven chemical cleaning solutions for 6 months: Invisalign cleaning crystals, Retainer Brite, Polident, Listerine mouthwash, 2.5% acetic acid, 0.6% NaClO, and 3% H2O2. Seventy specimens (n = 10 per method, 50.8 mm × 12.7 mm × 1.0 mm) were exposed to the different solutions twice a week for 2 minutes or according to manufacturer's instructions and stored in artificial saliva at 37°C. Another group of specimens (n = 10) was brushed with a standardized toothbrushing machine for 2 minutes twice a week. At baseline and 6 months, light transmittance, surface roughness and flexural modulus of the specimens were quantified using spectrophotometry, profilometry, and three-point bend testing, respectively. Qualitative assessment was performed using scanning electron microscopy (SEM). Statistical analyses were accomplished at a significance level of .05. RESULTS: The results indicated that light transmittance through the specimens decreased significantly from baseline for all cleaning methods at 6 months. Flexural modulus of the specimens decreased significantly for all cleaning methods except Invisalign crystals and Retainer Brite ( P > .05). The Listerine group demonstrated the worst light transmittance change while H2O2 demonstrated the greatest change in flexural modulus of the specimens compared with other cleaning methods; however, no qualitative difference was observed using SEM analysis. CONCLUSIONS: The results suggest that different cleaning methods affect long-term physical properties of the ACE retainer material. At the present time, none of these cleaning methods is ideal for copolyester retainer material.

Computerized measurement of the location and value of the minimum sagittal linear dimension of the upper airway on reconstructed lateral cephalograms compared with 3-dimensional values.

INTRODUCTION: Identifying the location and value of the smallest airway dimension can be useful in screening and planning treatment for patients with obstructive sleep apnea. Our objectives in this study were to (1) objectively identify the vertical location and value of the minimum sagittal linear dimension (MSLD) on 2-dimensional reconstructed lateral cephalograms (RLCs), (2) compare the location and value of the MSLD on RLCs with the vertical location and sagittal dimension of the minimum cross-sectional area (MCSA), and (3) investigate the association between the MSLD on RLCs and both the MCSA and the airway volume. METHODS: Cone-beam computed tomography (CBCT) scans of 91 patients, in 3 age groups (<20, 20-40, and >40 years), were used to perform 3-dimensional assessments of the upper airway and reconstruct lateral cephalograms. Airway volume, MCSA, vertical level, and sagittal dimension of MCSA on the CBCT scans were obtained using Dolphin 3D software (version 11.7; Dolphin Imaging, Chatsworth, Calif). Customized software was used to objectively obtain the location and value of the MSLD of the airway on RLCs. RESULTS: In all age groups, correlation tests showed significant correlations between the MSLD on RLCs and both the MCSA (rs ≥0.59; P <0.001) and the airway volume (rs ≥0.37; P <0.05). Additionally, there were significant correlations between the vertical location of the MSLD and the vertical location of the MCSA (rs ≥0.41; P <0.05) and between the MSLD and the sagittal dimension of the MCSA (r ≥0.61; P <0.001). Bland-Altman plots for the MSLD and the sagittal dimension of the MCSA showed much narrower 95% limits of agreement compared with the Bland-Altman plots for the vertical locations of the MSLD and the MCSA. CONCLUSIONS: Two-dimensional images may be used as a screening tool and to identify the sagittal dimension of the smallest airway dimension. However, comprehensive assessment of airway characteristics is better achieved with CBCT-based 3-dimensional evaluation.

Extracorporeal shockwave treatment impedes tooth movement in rats.

BACKGROUND: Accelerated tooth movement has been a topic of interest for orthodontic research recently. Surgically facilitated orthodontic treatment has been shown to be an effective approach to accelerate tooth movement; however, it remains invasive, requires additional surgery, and may increase post-operative complications. In this study, we evaluate the effects of extracorporeal shockwave treatment (ESWT), a non-invasive approach to regenerate alveolar bone, on orthodontic tooth movement in rats. MATERIALS AND METHODS: Seventy-two male rats, aged 10 weeks old, were subjected to 10-cN closed-coil nickel-titanium springs for unilateral maxillary first molar tooth movement. One group of rats received a single treatment of extracorporeal shockwave treatment at 500 impulses at energy flux density 0.1 mJ/mm2, with a pulse rate of 5 pulses per second immediately after spring installation while the non-ESWT-treated group served as a control group. The rats were sacrificed at day 3, 7, 14, 21 and 28 for tooth movement evaluation and sample analyses. Faxitron radiography, histological, double bone labeling and gene expression analyses were performed. Serum biochemistry was evaluated at day 3, 7 and 28 of the study. Kruskal-Wallis analysis of variance was used to determine the mean difference among groups, and multiple comparisons were analyzed by Mann-Whitney-U tests with a significance level = 0.05. RESULTS: The results demonstrated that tooth movement in the ESWT-treated rats (0.11 ± 0.07 mm) was impeded compared to the tooth movement in the non-ESWT-treated rats (0.44 ± 0.09 mm). ESWT up-regulated several osteoblastic and osteoclastic gene markers and cytokines; however, the effects on osteoclasts were only transient. Double-fluorescence bone labeling demonstrated that osteoblastic activity increased after ESWT treatment. There was no difference in systemic RANKL/OPG ratio between groups. CONCLUSIONS: ESWT at 500 impulse at energy flux density 0.1 mJ/mm2 increased osteoblast and osteoclast activities and imbalanced bone remodeling resulting in impeded tooth movement in rats.

Long-term effects of seven cleaning methods on light transmittance, surface roughness, and flexural modulus of polyurethane retainer material.

OBJECTIVES: To evaluate the long-term effects of seven different cleaning methods on light transmittance, surface roughness, and flexural modulus of a polyurethane retainer material. MATERIALS AND METHODS: Polyurethane retainer specimens (Vivera®, Align Technology Inc) (70 specimens, n = 10 per method, 50.8 mm × 12.7 mm × 1.0 mm) were exposed to seven cleaning methods twice a week for 6 months. Before treatment and after 6 months, light transmittance, surface roughness, and flexural modulus of the specimens were quantified. Qualitative assessment of randomly selected specimens from each solution was performed at baseline and after 6 months using a scanning electron microscope. Statistical analyses were performed at the .05 significance level. RESULTS: Of the three test variables, light transmittance through the specimens was the only one that changed significantly from baseline to 6 months for all cleaning solutions, with all of them causing a decrease. However, except for 0.6% sodium hypochlorite showing a change in surface roughness values and 2.5% vinegar and toothbrushing showing an increase in flexural modulus, none of the other four cleaning methods resulted in significant changes in surface roughness or flexural modulus values for the polyurethane specimens between baseline and after 6 months. CONCLUSIONS: Of the seven cleaning methods, Invisalign® cleaning crystals, Polident®, and Listerine® showed the least amount of change in light transmittance values for the polyurethane specimens over 6 months, and they had no effect on surface roughness and flexural modulus values.

Secretory microRNA-29 expression in gingival crevicular fluid during orthodontic tooth movement.

Secretory microRNAs (miRNAs) have been used increasingly as biomarkers for cancers, autoimmune diseases and inflammatory diseases. They are reported as being freely circulated or encapsulated in microvesicles such as exosomes. This study was performed to elucidate the presence of miRNAs with exosomes in human gingival crevicular fluid (GCF), and the expression profile of miRNA-29 during orthodontic tooth movement. Four healthy volunteer and fifteen orthodontic patients were enrolled in the study. Secretory miRNA in GCF was collected and analyzed using a bioanalyzer, realtime PCR and Western blot analysis. The expression profile of secretory miR-29 family in GCF was analyzed during the course of canine retraction for 6 weeks. The results demonstrated the presence of miRNAs in the GCF. After series of ultracentrifugation and RT-PCR array, exosome-depleted fractions and pellets were isolated and we found that secretory miRNAs were detected in both the exosome-associated fraction and the exosome-depleted supernatant fraction; however, the concentration of miRNAs was higher in the exosome-associated fraction than in the exosome-depleted fraction suggesting a close association between the secretory miRNAs and exosomes in GCF. We also demonstrated the increased expression profiles of miR-29 family during six weeks of orthodontic tooth movement in humans. Secretory miRNAs are present in GCF and secretory miRNA-29 family expression profiles increase during the tooth movement in humans. Secretory miRNA-29 in GCF could serve as potential biomarkers for periodontal remodeling.

Three-dimensional assessment of soft tissue changes associated with bone-anchored maxillary protraction protocols.

INTRODUCTION: The aim of this study was to assess the 3-dimensional soft tissue changes in growing Class III patients with maxillary deficiency associated with 2 bone-anchored maxillary protraction protocols in relation to an untreated control group of Class III patients. METHODS: Growing skeletal Class III patients between the ages of 10 and 14 years participated in this study. In group 1 (n = 10), skeletally anchored facemasks were used with miniplates placed at the zygomatic buttress. In group 2 (n = 10), the patients were treated with Class III elastics extending from infrazygomatic miniplates in the maxilla to symphyseal miniplates in the mandible. Group 3 (n = 10) was an untreated control group. Three-dimensional stereophotogrammetry images were acquired before and after treatment, and then superimposed and analyzed. In addition, lateral cephalometric radiographs were analyzed. RESULTS: The maxilla moved forward significantly in groups 1 and 2 compared with the untreated control group (group 1, 4.87 mm; group 2, 5.81 mm). The 3-dimensional soft tissue analysis showed significant treatment effects; the major changes were observed in the upper lips, cheeks, and middle of the face, which had a significant positive sagittal displacement in both treatment groups. The lower lip and chin area showed significant negative sagittal changes that indicated that the soft tissue growth in this area was restrained with backward displacement especially in group 1 more than in group 2. CONCLUSIONS: The 2 bone-anchored maxillary protraction protocols effectively improved the Class III concave soft tissue profile.

Effects of unilateral premolar extraction treatment on the dental arch forms of Class II subdivision malocclusions.

INTRODUCTION: A retrospective study evaluating posttreatment symmetry in dental arch form and midlines was carried out in Class II subdivision patients treated with unilateral and bilateral maxillary premolar extractions. METHODS: Using Geomagic (version 14; Geomagic, Research Triangle Park, NC) and MATLAB (version 8.4; MathWorks, Natick, Mass) software, best-fit curves expressed as quartic polynomials were generated for 13 Class II subdivisions treated with unilateral extractions and 20 treated with bilateral maxillary premolar extractions. Transverse and sagittal measurements were recorded to assess symmetry. Dental models were superimposed on constructed reference planes to generate average posttreatment arches. Statistical comparisons were performed with the significance level set at P ≤0.05. RESULTS: The unilateral extraction group showed significant differences in transverse arch forms between the right and left sides in the anterior, anterior-middle, and middle segments of the arch, and all regions other than the posterior segment in the sagittal dimension. Significant differences were found between groups in the anterior and anterior-middle segments of the arch transversely, the middle and middle-posterior segments sagittally, and the midline deviation relative to the midsagittal plane. Superimposed average arches showed similar results. CONCLUSIONS: Unilateral maxillary extraction treatment generally results in a narrower and more posteriorly displaced arch form on the extraction side, with a deviated maxillary midline toward the extraction side of the arch.

3D Evaluation of Palatal Rugae in Identical Twins.

The study of identical twins can point out potential limitations in biometrics and forensic odontology. This case report presents three-dimensional (3D) palatal rugae analysis in monozygotic twins utilizing digital models obtained directly by scanning the maxillary dental arch with the iTero® intraoral digital scanner. The results show that the rugae patterns contain related but not identical features between the pair of identical twins. Dental study models taken on a regular basis for diagnosis and treatment planning in dentistry include the palatal rugae, which could be valuable to forensics in identical twin identification cases.

Dentoalveolar and arch dimension changes in patients treated with miniplate-anchored maxillary protraction.

INTRODUCTION: The aim of this study was to evaluate dentoalveolar and arch dimension changes in 2 miniplate-anchored maxillary protraction protocols in relation to an untreated control group using 3-dimensional digital models. METHODS: Thirty growing Class III subjects with maxillary deficiency in the late mixed or early permanent dentition phase were randomly divided into 3 groups. In group 1 (n = 10), patients were treated with skeletally anchored facemasks anchored with miniplates placed at the zygomatic buttress. In group 2 (n = 10), patients were treated with Class III elastics extending from infrazygomatic miniplates in the maxilla to symphyseal miniplates in the mandible. Group 3 (n = 10) was an untreated control group. The decision to discontinue orthopedic treatment was made when the patients had 3 to 4 mm of positive anterior overjet. Pretreatment, posttreatment, and observation 3-dimensional digital models were analyzed, superimposed, 3 dimensionally mapped, and sectioned. RESULTS: In this study, there were no significant changes in maxillary arch depth and maxillary or mandibular intermolar width before and after maxillary protraction or after the observation period in the control group. The mandibular arch depth decreased by a small but statistically significant amount only in groups 1 and 3. Superimposition of the pretreatment and posttreatment or observation maxillary 3-dimensional digital models showed minimal clinically significant dentoalveolar changes. CONCLUSIONS: Miniplate-anchored maxillary protraction protocols can accomplish maxillary advancement by eliminating movements of teeth and dentoalveolar changes. No spontaneous improvement in transverse deficiency was detected after correction of the anteroposterior deficiency at this age. Consequently, patients with transverse maxillary deficiency should have rapid maxillary expansion before or during the miniplate-anchored protraction period to improve the transverse deficiency.

Racial and sex differences in timing of the cervical vertebrae maturation stages.

INTRODUCTION: Our objective was to investigate skeletal maturation of female and male subjects from different racial groups by comparing the cervical vertebrae maturation (CVM) stages. METHODS: The study included 3 racial groups: white, African American, and Hispanic subjects. Each group was subdivided into female and male. The age range of the subjects was between 7 and 18 years. The sample included 60 lateral cephalographs for each subgroup. Skeletal maturation of the cervical vertebrae was assessed according to a method that described 6 CVM stages. RESULTS: Racial differences were evident in the mean ages of CVM stages 2, 3, 4, and 5 (P = 0.002; P = 0.003; P = 0.001; and P = 0.001, respectively) among females; among males, only stage 3 was different (P = 0.001). Sex differences in the mean ages of stages 1, 2, and 3 in Hispanic subjects (P <0.001), and in stages 2 and 3 in African American subjects (P = 0.019 and P <0.001) and white subjects (P = 0.004 and P <0.001) were detected. CONCLUSIONS: In both sexes, racial differences were not apparent between whites and African Americans, but differences were evident between Hispanics vs both whites and African Americans. Sex differences were apparent between the sexes in each of the 3 ethnic groups in CVM stages 2 and 3. No sex differences were detected in stages 4, 5, or 6 in any of the 3 racial groups. It is recommended to consider racial and sex differences when using the CVM stage as a skeletal maturation indicator.

Randomized Trial of Plaque-Identifying Toothpaste: Decreasing Plaque and Inflammation.

BACKGROUND: Randomized data are sparse about whether a plaque-identifying toothpaste reduces dental plaque and nonexistent for inflammation. Inflammation is intimately involved in the pathogenesis of atherosclerosis and is accurately measured by high-sensitivity C-reactive protein (hs-CRP), a sensitive marker for cardiovascular disease. The hypotheses that Plaque HD (TJA Health LLC, Joliet, Ill), a plaque-identifying toothpaste, produces statistically significant reductions in dental plaque and hs-CRP were tested in this randomized trial. METHODS: Sixty-one apparently healthy subjects aged 19 to 44 years were assigned at random to this plaque-identifying (n = 31) or placebo toothpaste (n = 30) for 60 days. Changes from baseline to follow-up in dental plaque and hs-CRP were assessed. RESULTS: In an intention-to-treat analysis, the plaque-identifying toothpaste reduced mean plaque score by 49%, compared with a 24% reduction in placebo (P = .001). In a prespecified subgroup analysis of 38 subjects with baseline levels >0.5 mg/L, the plaque-identifying toothpaste reduced hs-CRP by 29%, compared with a 25% increase in placebo toothpaste (P = .041). CONCLUSION: This plaque-identifying toothpaste produced statistically significant reductions in dental plaque and hs-CRP. The observed reduction in dental plaque confirms and extends a previous observation. The observed reduction in inflammation supports the hypothesis of a reduction in risks of cardiovascular disease. The direct test of this hypothesis requires a large-scale randomized trial of sufficient size and duration designed a priori to do so. Such a finding would have major clinical and public health implications.

Secular trends in the timing of skeletal maturation as assessed by the cervical vertebrae maturation method.

Objective: To investigate the presence of secular trends in skeletal maturation of girls and boys as assessed by the use of cervical vertebrae bones. Materials and methods: The study compared two main groups: the first included data collected from the Denver growth study (1930s to 1960s) and the second included data collected from recent pretreatment records (1980s to 2010s) of patients from the orthodontic clinic of a North American University. The records from the two groups were all for Caucasian subjects. The sample for each group included 78 lateral cephalographs for girls and the same number for boys. The age of the subjects ranged from 7 to 18 years. Cervical vertebrae maturation (CVM) stages were directly assessed from the radiographs according to the method described by Hassel and Farman in which six CVM stages were designated from cervical vertebrae 2, 3, and 4. Results: The mean age of girls from the Denver growth study and girls from the university clinic in each of the six CVM stages was not different at P ≤0.05. However, the mean age of boys from the two groups was not different only in stage 3 (P = 0.139) and stage 4 (P = 0.211). Conclusions: The results showed no evidence to indicate a tendency for earlier skeletal maturation of girls or boys. Boys in the university group started their skeletal maturation later than boys in the Denver group and completed their maturation earlier. Gender was a significant factor affecting skeletal maturation stages in both Denver and university groups.

Comparative evaluation of 2 skeletally anchored maxillary protraction protocols.

INTRODUCTION: The aim of this study was to evaluate and compare the effects of 2 protocols of bone-anchored maxillary protraction with an untreated control group. METHODS: Thirty growing Class III subjects with maxillary deficiency in the late mixed or early permanent dentition were included in the study. In group 1 (n = 10), skeletally anchored facemasks were used with miniplates placed at the zygomatic buttress. In group 2 (n = 10), the patients were treated with Class III elastics extending from infrazygomatic miniplates in the maxilla to symphyseal miniplates in the mandible. Group 3 (n = 10) was an untreated control group. Pretreatment and posttreatment cephalometric radiographs were analyzed. RESULTS: The treatment periods were 8 and 8.9 months in groups 1 and 2, respectively, and the untreated control group was observed for 9.4 months. The maxilla moved forward significantly in groups 1 and 2 compared with the untreated control group (4.87 mm in group 1, 5.81 mm in group 2); overjet and maxillary incisor display were improved without proclination or mesialization of the maxillary teeth relative to the maxillary base. Soft tissue harmony demonstrated the great improvement. However, group 1 showed more opening rotation of the mandible and lingual inclination of the mandibular incisors than did group 2. CONCLUSIONS: The 2 skeletal anchorage protocols for maxillary protraction effectively resolved the severe maxillary deficiently in growing Class III patients. However, vertical changes and retroclination of the mandibular incisors were better controlled by Class III elastics extending from the infrazygomatic miniplates in the maxilla to the symphyseal miniplates in the mandible (group 2).

Bonding of Metal Orthodontic Attachments to Sandblasted Porcelain and Zirconia Surfaces.

This study evaluates tensile bond strength (TBS) of metal orthodontic attachments to sandblasted feldspathic porcelain and zirconia with various bonding protocols. Thirty-six (36) feldspathic and 36 zirconia disc samples were prepared, glazed, embedded in acrylic blocks and sandblasted, and divided into three groups according to one or more of the following treatments: hydrofluoric acid 4% (HF), Porcelain Conditioner silane primer, Reliance Assure® primer, Reliance Assure plus® primer, and Z Prime™ plus zirconia primer. A round traction hook was bonded to each sample. Static tensile bond strength tests were performed in a universal testing machine and adhesive remnant index (ARI) scoring was done using a digital camera. One-way ANOVA and Pearson chi-square tests were used to analyze TBS (MPa) and ARI scores. No statistically significant mean differences were found in TBS among the different bonding protocols for feldspathic and zirconia, p values = 0.369 and 0.944, respectively. No statistically significant distribution of ARI scores was found among the levels of feldspathic, p value = 0.569. However, statistically significant distribution of ARI scores was found among the levels of zirconia, p value = 0.026. The study concluded that silanization following sandblasting resulted in tensile bond strengths comparable to other bonding protocols for feldspathic and zirconia surface.

Objective adherence to positive airway pressure therapy in an Australian paediatric cohort.

PURPOSE: This study aimed to objectively measure adherence (compliance) and effectiveness of CPAP and BiLevel pressure support in an Australian paediatric population and determine factors associated with adherence outcomes. METHODS: Data was collected as part of routine clinical care from 2011 to 2013. Adherence was recorded by downloads from the PAP device. "Adequate" adherence was defined as ≥4 h/night for 70 % of days used. Effectiveness of therapy was measured by polysomnography (PSG) pre- and post-PAP initiation. One year follow-up was undertaken to determine the long-term utilisation of PAP therapy. RESULTS: Ninety-nine children were included (55 CPAP, 44 BiLevel). Mean age and BMI z-score were 6.9 ± 5.5 years and 0.1 ± 2.0 for CPAP and 9.8 ± 5.9 years and -0.5 ± 2.6 for BiLevel, respectively. At initial download, adequate adherence was observed in 75 % of CPAP and 91 % of BiLevel users. Mean hours of use (per night) for all nights used was 6.8 ± 2.8 and 9.3 ± 3.6 h, respectively. PSG demonstrated that CPAP use was associated with >60 % decrease in the obstructive apnoea hypopnoea index (OAHI, 19.0 ± 18.4 to 2.4 ± 3.1; p < 0.001). BiLevel use was associated with improved baseline SaO2 and TcCO2 (SaO2, 92.5 ± 5.4 % to 95.5 ± 2.9 %; p = 0.001 and reduction in TcCO2, 50.0 ± 10.9 mmHg to 44.8 ± 7.6 mmHg; p = 0.01). At follow-up, 22 (40 %) patients on CPAP and 26 (59 %) on BiLevel continued with therapy, and amongst these, adequate adherence was maintained in 76 % of CPAP and 80 % of Bilevel users. CONCLUSIONS: In this Australian paediatric cohort (predominantly non-obese), adherence with BiLevel was greater than for CPAP. Over half of our population continue to utilise PAP therapy 1 year later, and amongst these cases, adequate adherence was maintained.