Symmetry of palatal shape during the first year of life in healthy infants.

OBJECTIVES: The purpose of this study was to quantify the symmetry of the alveolar process of the maxilla and palate during the first year of life in healthy infants with the help of a semiautomatic segmentation technique. MATERIALS AND METHODS: Maxillary plaster models of seventy healthy babies at 0, 3, 6, 9, and 12 months were collected and digitized. A semiautomatic segmentation tool was used to extract the alveolus and palate. The resulting model was aligned within a reference frame and mirrored on its medial plane. Distance maps were created and analyzed to compare and quantify the differences between the two hemispheres. Additional hemispherical width and area measurements were performed. An ANOVA test with additional post hoc tests was performed to check if the symmetry changed during development. Finally, the results were tested on intra- and interobserver variability. RESULTS: The absolute mean inter-surface distance between the original and mirrored models in each age group ranged between 0.23 and 0.30 mm. Width and area analysis showed a small but significant larger left palatal hemisphere. ANOVA and post hoc tests showed no significant difference in symmetry between groups. Reliability analysis showed no significant differences between observers. CONCLUSIONS: This study showed that in this infant population, only a small degree of palatal asymmetry was present, which can be considered as normal and clinically irrelevant. CLINICAL RELEVANCE: The data from this study can be used in future comparative studies as reference data. Furthermore, modeling of these data can help in predicting the growth pattern, which may lead to improved treatment protocols for children with craniofacial anomalies.

[Activator or Herbst, what's best?] / Activator of Herbst; wat is beter?

In this article, the short- and long-term results of two types of functional appliances are discussed regarding their ability to stimulate the mandibular growth at mandibular retrognathia and reduce an increased overjet. Removable functional appliances, or activators, are compared to a fixed functional appliance, the Herbst appliance. The activator, often consisting of an acrylic base, is advised to be worn for 12 to 20 hours a day. The Herbst appliance consists of interconnected bands around the molar- and premolar bands, keeping the mandibula continuously positioned forward by means of hinges or telescopes. In the short-term, both appliances are effective in reducing the overjet, improving the molar-occlusion and reducing the mandibular retrognathia. The comparative literature is inconclusive as to which appliance is more effective on which level, skeletal or dentoalveolar. The removable appliances are more likely to be accepted at a younger age, whilst the fixed appliances are more suitable for the adolescents. The stability of the long-term treatment effects is minimally described in the existing literature. However, the highest stability rate seems to apply to the Herbst appliance. The impact of a widely applied second phase of treatment with fixed appliances, with possible use of intermaxillary class II elastics and retention using functional appliances is barely taken into account.

[Opinions on orthodontics: an online questionnaire among NTVT readers]. / Mening over orthodontie: een online enquête onder NTVT-lezers.

By means of an online questionnaire, the opinions of dental health practitioners on 'orthodontics' were assessed on the basis of 10 statements. There were 523 responses, 51% of which were from general practitioners, a relatively large number from orthodontists (31%) and 18% from other dental health practitioners. Concerning indication of treatment, dental health prior to treatment and the value of straightened teeth, opinions were clearly positive, somewhat more among orthodontist than among general practitioners. Patients knowledge concerning orthodontics and the negative side of orthodontics and their trust in the durability of orthodontic retention are all considered to be more positively present in patients by orthodontists than general practitioners. 1 in 3 non-orthodontists considered carrying out orthodontic procedures in the general practice to be fine. More than 90% of orthodontists disagreed. Female dental practitioners more often consider orthodontic treatment to belong with an orthodontist. The number of women was equally divided across the different groups.

Three dimensional maxillary growth modeling in newborns.

OBJECTIVES: The aim of this study was to develop an accurate and intuitive semi-automatic segmentation technique to calculate an average maxillary arch and palatal growth profile for healthy newborns in their first year of life. MATERIALS AND METHODS: Seventy babies born between 1985 and 1988 were included in this study. Each child had five impressions made in the first year after birth that were digitalized. A semi-automatic segmentation tool was developed and used to assess the maxillary dimensions. Finally, random effect models were built to describe the growth and build a simulation population of 10,000 newborns. The segmentation was tested for inter- and intra-observer variability. RESULTS: The Pearson correlation coefficient for each of the variables was between 0.94 and 1.00, indicating high inter-observer agreement. The paired sample t test showed that, except for the tuberosity distance, there were small, but significant differences in the landmark placements between observers. Intra-observer repeatability was high, with Pearson correlation coefficients ranging from 0.87 to 1.00 for all measurements, and the mean differences were not significant. A third or second degree growth curve could be successfully made for each parameter. CONCLUSIONS: These findings indicated this method could be used for objective clinical evaluation of maxillary growth. CLINICAL RELEVANCE: The resulting growth models can be used for growth studies in healthy newborns and for growth and treatment outcome studies in children with cleft lip and palate or other craniofacial anomalies.

[Orthodontic treatment of a malocclusion with a compromised central upper incisor]. / Orthodontische behandeling van een malocclusie met een gecompromitteerde centrale bovenincisief.

An 11-year-old girl presented at an orthodontist asking for the correction of the crooked position of her upper and lower front teeth. In addition, the patient was concerned about the abnormal shape and size of tooth 21. There was a disto-occlusion, crowding and tooth gemination of tooth 21 with the shape of a dens invaginatus. The tooth, moreover, was infected. Teeth 21 and 14 were extracted as part of the treatment. By means of a guided transposition, tooth 23 was brought to the extraction site of tooth 21. Treatment was performed with hybrid fixed appliance techniques.

Direct Observation of Nonlinear Coupling between Pedestal Modes Leading to the Onset of Edge Localized Modes.

Prior to eruptive events such as edge localized modes (ELMs), quasicoherent fluctuations, referred to as pedestal modes, are observed in the edge of fusion devices. We report on the investigations of nonlinear coupling between these modes during quasistationary inter-ELM phases leading to the ELM onset. Three dominant modes, with density and magnetic signatures, are identified as key players in the triggering mechanism of certain classes of ELMs. We demonstrate that one of these modes is amplified by the two others through three wave interactions. The amplified mode is radially shifted relative to the other two modes towards the last-closed flux surface as the ELM event approaches. Our results suggest that nonlinear coupling of pedestal modes, associated with radial distortions pushing out of the pedestal, is a possible mechanism for the triggering of low frequency ELMs relevant for future fusion devices.

Observation of Critical-Gradient Behavior in Alfvén-Eigenmode-Induced Fast-Ion Transport.

Experiments in the DIII-D tokamak show that fast-ion transport suddenly becomes stiff above a critical threshold in the presence of many overlapping small-amplitude Alfvén eigenmodes (AEs). The threshold is phase-space dependent and occurs when particle orbits become stochastic due to resonances with AEs. Above threshold, equilibrium fast-ion density profiles are unchanged despite increased drive, and intermittent fast-ion losses are observed. Fast-ion Dα spectroscopy indicates radially localized transport of the copassing population at radii that correspond to the location of midcore AEs. The observation of stiff fast-ion transport suggests that reduced models can be used to effectively predict alpha profiles, beam ion profiles, and losses to aid in the design of optimized scenarios for future burning plasma devices.

The Asher-McDade Aesthetic Index in Comparison With Two Scoring Systems in Nonsyndromic Complete Unilateral Cleft Lip and Palate Patients.

OBJECTIVE: To compare the Asher-McDade aesthetic index with 2 systems used to score the appearance of the nasolabial area in patients with a complete cleft lip and palate. DESIGN: Retrospective analysis of the results of complete unilateral cleft lip and palate patients. SETTING: Academic Center for Dentistry of Amsterdam and the VU University Medical Center. PATIENTS: Six-year-olds with complete unilateral cleft lip and palate. MAIN OUTCOME MEASURES: Cleft lip and palate patients assessed using the scoring system proposed by Prahl et al, a 5-point ordinal scale, and the scoring system proposed by Asher-McDade et al by 6 judges, 3 orthodontists, and 3 plastic surgeons. A calculation of intra- and interobserver reliability was made. A comparison was made of all the assessment methods using Kendalls' tau. RESULTS: Photographs of 55 children (38 boys and 17 girls) with complete unilateral cleft lip and palate were assessed. For the scoring system of Prahl et al, interobserver reliability varied from 0.43 to 0.53, for the 5-point scale between 0.45 and 0.57, and for the scoring system by Asher-McDade et al these varied between 0.52 and 0.66. Multiple significant correlations were found between the used scoring systems. CONCLUSION: It can be concluded that the Asher-McDade aesthetic index is still superior to the other scoring systems used in this study. However, all 3 scoring systems can reliably be used when 3 or more observers are used.

Comparison of two scoring systems in the assessment of nasolabial appearance in cleft lip and palate patients.

OBJECTIVE: The aim of this study was to determine the reliability of 2 scoring systems. DESIGN: This study used a retrospective analysis of the results of complete unilateral cleft lip and palate patients. SETTING: The study was conducted at the VU Medical Center and the Academic Center for Dentistry of Amsterdam. PATIENTS: Patients were complete unilateral cleft lip and palate patients at the age of 6 years. MAIN OUTCOME MEASURES: Assessment of the nose and lip together and separately with a numerical photographic reference scoring system and with a 5-point ordinal scale without the use of a reference photograph by 6 judges. Intraobserver and interobserver reliability was calculated; both ways of assessment were compared by using Kendall tau. RESULTS: Photographs were available of 55 children (6 years old, 38 boys and 17 girls) with a complete unilateral cleft lip and palate. The interobserver reliabilities of the lip and nose together were 0.53 and, for the nose and lip separately, 0.51 and 0.43, respectively with the use of the numerical scale. In the 5-point scale, these were 0.55 for the nose and lip together and 0.57 and 0.45 for the nose and lip separately, respectively. Furthermore, it was found that the lip dominates in the scorings of the lip and nose together (linear regression analysis). CONCLUSIONS: The 2 tested systems are equivalent in their reliability and outcome. The lip is dominating in the overall scorings. It is advocated to use the 5-point scale without the use of a reference photograph and to assess the lip and nose separately.

Mitigation of Alfvén activity in a tokamak by externally applied static 3D fields.

The application of static magnetic field perturbations to a tokamak plasma is observed to alter the dynamics of high-frequency bursting Alfvén modes that are driven unstable by energetic ions. In response to perturbations with an amplitude of δB/B∼0.01 at the plasma boundary, the mode amplitude is reduced, the bursting frequency is increased, and the frequency chirp is smaller. For modes of weaker bursting character, the magnetic perturbation induces a temporary transition to a saturated continuous mode. Calculations of the perturbed distribution function indicate that the 3D perturbation affects the orbits of fast ions that resonate with the bursting modes. The experimental evidence represents an important demonstration of the possibility of controlling fast-ion instabilities through "phase-space engineering" of the fast-ion distribution function, by means of externally applied perturbation fields.

Enhanced localized energetic-ion losses resulting from single-pass interactions with Alfvén eigenmodes.

We report the first observation of prompt neutral beam-ion losses due to nonresonant scattering induced by toroidal and reversed shear Alfvén eigenmodes in the DIII-D tokamak. The coherent losses are of full energy beam ions expelled from the plasma on their first poloidal orbit. The first-orbit loss mechanism causes enhanced, concentrated losses on the first wall exceeding nominal levels of prompt losses. The loss amplitude scales linearly with the mode amplitude. The data provide a novel and direct measure of the radial excursion or scatter of particles induced by individual modes and may shed light on the mechanism for the scattering of energetic particles in interstellar medium.

Fractional resonances between waves and energetic particles in tokamak plasmas.

From numerical simulation and analytical modeling it is shown that fast ions can resonate with plasma waves at fractional values of the particle drift-orbit transit frequency when the plasma wave amplitude is sufficiently large. The fractional resonances, which are caused by a nonlinear interaction between the particle orbit and the wave, give rise to an increased density of resonances in phase space which reduces the threshold for stochastic transport. The effects of the fractional resonances on spatial and energy transport are illustrated for an energetic particle geodesic acoustic mode but they apply equally well to other types of MHD activity.

High-harmonic fast-wave power flow along magnetic field lines in the scrape-off layer of NSTX.

A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

Integrated package of electron cyclotron emission imaging data processing and forward modeling in OMFIT.

An Electron Cyclotron Emission Imaging (ECEI) data analysis module has been developed for the OMFIT platform to accommodate the needs of users at the DIII-D tokamak for physics applications. The user can easily access the ECEI spatial observation windows in the plasma that are calculated based on the automatically retrieved hardware setup and available DIII-D equilibria, perform spectral analysis, and obtain 2D electron temperature fluctuation images. The module provides a powerful data post-processing package for extracting important physics parameters from the 2D measurements, including the radial structure and poloidal mode number of Alfven eigenmodes, as well as the frequency-vs-wavenumber dispersion relationship of broadband MHD. The module propagates characterized synthetic fluctuations for the user, so one can perform forward modeling tasks with simple analytical fluctuations.

Performance demonstration of vacuum microwave components critical for the operation of the ITER low-field side reflectometer.

Final design studies in preparation for manufacturing have been performed for functional components of the vacuum portion of the ITER Low-Field Side Reflectometer (LFSR). These components consist of an antenna array, electron cyclotron heating (ECH) protection mirrors, phase calibration mirrors, and vacuum windows. Evaluation of these components was conducted at the LFSR test facility and DIII-D. The antenna array consists of six corrugated-waveguide antennas for simultaneous profile, fluctuation, and Doppler measurements. A diffraction grating, incorporated into the plasma-facing miter bend, provides protection of sensitive components from stray ECH at 170 GHz. For in situ phase calibration of the LFSR profile reflectometer, an embossed mirror is incorporated into the adjacent miter bend. Measurements of the radiated beam profile indicate that these components have a small, acceptable effect on mode conversion and beam quality. Baseline transmission characteristics of the dual-disk vacuum window are obtained and are used to guide ongoing developments. Preliminary simulations indicate that a surface-relief structure on the window surfaces can greatly improve transmission. The workability of real-time phase measurements was demonstrated on the DIII-D profile reflectometer. The new automated real-time analysis agrees well with the standard post-processing routine.

The Lateral Ventricles: A Detailed Review of Anatomy, Development, and Anatomic Variations.

The cerebral ventricles have been studied since the fourth century BC and were originally thought to harbor the soul and higher executive functions. During the infancy of neuroradiology, alterations to the ventricular shape and position on pneumoencephalography and ventriculography were signs of mass effect or volume loss. However, in the current era of high-resolution cross-sectional imaging, variation in ventricular anatomy is more easily detectable and its clinical significance is still being investigated. Interpreting radiologists must be aware of anatomic variations of the ventricular system to prevent mistaking normal variants for pathology. We will review of the anatomy and development of the lateral ventricles and discuss several ventricular variations.

Synthetic diagnostics platform for fusion plasmas (invited).

A Synthetic Diagnostics Platform (SDP) for fusion plasmas has been developed which provides state of the art synthetic reflectometry, beam emission spectroscopy, and Electron Cyclotron Emission (ECE) diagnostics. Interfaces to the plasma simulation codes GTC, XGC-1, GTS, and M3D-C1 are provided, enabling detailed validation of these codes. In this paper, we give an overview of SDP's capabilities, and introduce the synthetic diagnostic modules. A recently developed synthetic ECE Imaging module which self-consistently includes refraction, diffraction, emission, and absorption effects is discussed in detail. Its capabilities are demonstrated on two model plasmas. The importance of synthetic diagnostics in validation is shown by applying the SDP to M3D-C1 output and comparing it with measurements from an edge harmonic oscillation mode on DIII-D.

Stratum corneum lipid abnormalities in surfactant-induced dry scaly skin.

Sodium dodecyl sulfate (SDS) has been used to induce a dry scaly skin condition in human subjects. Measurements of stratum (s.) corneum hydration, scaliness, and lipid composition reveal in vivo surfactant perturbations on desquamation. Subjects (n = 10) were briefly treated daily with a 4% aqueous solution of SDS on one lower leg over a period of 2 weeks. The other control leg received no treatments. At the end of the treatment period, both lower legs were evaluated for hydration using an electrical impedance technique and examined by an independent dermatologist using a visually based grading scale for surface roughness and scaliness. Shave biopsies were then excised from each lower leg for analysis of s. corneum lipids. Treatment resulted in decreased s. corneum hydration and increased surface scale/roughness. These physical changes were accompanied by significant changes in s. corneum lipid composition. While surfactant treatments did not alter the total quantity of lipids per gram s. corneum protein, significant changes in specific lipid classes were observed. The free cholesterol to cholesterol ester ratio increased while the quantity of total sterols remained constant. The distribution of certain ceramide species were altered while the quantity of total ceramides remained constant. Free fatty acids were resolved into 2 distinct bands, only one of which diminished upon treatment. These results are interpreted in terms of a model for surfactant-induced perturbation of keratinization which leads to abnormal s. corneum lipids and altered desquamation.

Effects of early treatment on maxillary arch development in BCLP. A study on dental casts between 0 and 4 years of age.

The present investigation analyses longitudinally the effects of early orthopaedic and/or surgical treatment on maxillary alveolar arch development in 30 children with a complete bilateral cleft lip and palate (BCLP). Palatal arch dimensions were measured on dental casts and their growth velocities during different treatment periods were calculated. Differences in growth velocities between consecutive treatment periods were examined and tested statistically. Furthermore, growth velocities were compared with those of 80 non-cleft children. Before lip closure, growth of the intercanine width of children with a BCLP and non-cleft children was comparable. Only for arch length significantly was less growth observed in BCLP patients in comparison with the control group. After lip closure, intercanine width, arch length and segmental angle diminished. During the intersurgical period, arch form seemed to adapt to a new muscular balance. Immediately after soft palate surgery, growth of the intercanine width and intertuberosity width was restricted. This negative growth was compensated in the postsurgical period, where a catch-up growth of intertuberosity width was even observed.

Technical overview of the millimeter-wave imaging reflectometer on the DIII-D tokamak (invited).

The two-dimensional mm-wave imaging reflectometer (MIR) on DIII-D is a multi-faceted device for diagnosing electron density fluctuations in fusion plasmas. Its multi-channel, multi-frequency capabilities and high sensitivity permit visualization and quantitative diagnosis of density perturbations, including correlation length, wavenumber, mode propagation velocity, and dispersion. The two-dimensional capabilities of MIR are made possible with 12 vertically separated sightlines and four-frequency operation (corresponding to four radial channels). The 48-channel DIII-D MIR system has a tunable source that can be stepped in 500 µs increments over a range of 56 to 74 GHz. An innovative optical design keeps both on-axis and off-axis channels focused at the cutoff surface, permitting imaging over an extended poloidal region. The integrity of the MIR optical design is confirmed by comparing Gaussian beam calculations to laboratory measurements of the transmitter beam pattern and receiver antenna patterns. Measurements are presented during the density ramp of a plasma discharge to demonstrate unfocused and focused MIR signals.