1,570 research outputs found
Moving an incisor across the midline: A treatment alternative in an adolescent patient
A 13-year-old sought treatment for a severely compromised maxillary left central incisor and an impacted fully developed left canine. Extraction of both teeth became necessary. As the key component of the revised comprehensive treatment plan, the right maxillary central incisor was moved into the position of the left central incisor. All other maxillary teeth were moved mesially to close any gaps. Active orthodontic treatment was completed after 34 months. Frenectomy, minor periodontal surgeries, and bonded lingual retainers were used to improve aesthetics and stabilize the tooth positions. The patient was pleased with the treatment outcome. Cone-beam computed tomography provided evidence that the tooth movement was accompanied by a deviation of the most anterior portion of the median palatine suture. This observation may make relapse more likely if long-term retention cannot be ensured. Root resorption was not observed as a consequence of the major tooth movement. (Am J Orthod Dentofacial Orthop 2011;139:533-43
Bonding with Self-etching Primers – Pumice or Pre-etch? An \u3cem\u3ein vitro\u3c/em\u3e Study
The purpose of this study was to compare the shear bond strengths (SBSs) of orthodontic brackets bonded with self-etching primer (SEP) using different enamel surface preparations. A two-by-two factorial study design was used. Sixty human premolars were harvested, cleaned, and randomly assigned to four groups (n = 15 per group). Teeth were bathed in saliva for 48 hours to form a pellicle. Treatments were assigned as follows: group 1 was pumiced for 10 seconds and pre-etched for 5 seconds with 37 per cent phosphoric acid before bonding with SEP (Transbond Plus). Group 2 was pumiced for 10 seconds before bonding. Group 3 was pre-etched for 5 seconds before bonding. Group 4 had no mechanical or chemical preparation before bonding. All teeth were stored in distilled water for 24 hours at 37°C before debonding. The SBS values and adhesive remnant index (ARI) score were recorded. The SBS values (±1 SD) for groups 1–4 were 22.9 ± 6.6, 16.1 ± 7.3, 36.2 ± 8.2, and 13.1 ± 10.1 MPa, respectively. Two-way analysis of variance and subsequent contrasts showed statistically significant differences among treatment groups. ARI scores indicated the majority of adhesive remained on the bracket for all four groups. Pre-etching the bonding surface for 5 seconds with 37 per cent phosphoric acid, instead of pumicing, when using SEPs to bond orthodontic brackets, resulted in greater SBSs
Bonding with Self-etching Primers – Pumice or Pre-etch? An \u3cem\u3ein vitro\u3c/em\u3e Study
The purpose of this study was to compare the shear bond strengths (SBSs) of orthodontic brackets bonded with self-etching primer (SEP) using different enamel surface preparations. A two-by-two factorial study design was used. Sixty human premolars were harvested, cleaned, and randomly assigned to four groups (n = 15 per group). Teeth were bathed in saliva for 48 hours to form a pellicle. Treatments were assigned as follows: group 1 was pumiced for 10 seconds and pre-etched for 5 seconds with 37 per cent phosphoric acid before bonding with SEP (Transbond Plus). Group 2 was pumiced for 10 seconds before bonding. Group 3 was pre-etched for 5 seconds before bonding. Group 4 had no mechanical or chemical preparation before bonding. All teeth were stored in distilled water for 24 hours at 37°C before debonding. The SBS values and adhesive remnant index (ARI) score were recorded. The SBS values (±1 SD) for groups 1–4 were 22.9 ± 6.6, 16.1 ± 7.3, 36.2 ± 8.2, and 13.1 ± 10.1 MPa, respectively. Two-way analysis of variance and subsequent contrasts showed statistically significant differences among treatment groups. ARI scores indicated the majority of adhesive remained on the bracket for all four groups. Pre-etching the bonding surface for 5 seconds with 37 per cent phosphoric acid, instead of pumicing, when using SEPs to bond orthodontic brackets, resulted in greater SBSs
Dimensional Changes of Upper Airway after Rapid Maxillary Expansion: A Prospective Cone-beam Computed Tomography Study
Introduction: The aim of this prospective study was to use cone-beam computed tomography to assess the dimensional changes of the upper airway in orthodontic patients with maxillary constriction treated by rapid maxillary expansion.
Methods: Fourteen orthodontic patients (mean age, 12.9 years; range, 9.7-16 years) were recruited. The patients with posterior crossbite and constricted maxilla were treated with rapid maxillary expansion as the initial part of their comprehensive orthodontic treatments. Before and after rapid maxillary expansion conebeam computed tomography scans were taken to measure the retropalatal and retroglossal airway changes in terms of volume, and sagittal and cross-sectional areas. The transverse expansions by rapid maxillary expansion were assessed between the midlingual alveolar bone plates at the maxillary first molar and first premolar levels. The measurements of the before and after rapid maxillary expansion scans were compared by using paired t tests with the Bonferroni adjustment for multiple comparisons.
Results: After rapid maxillary expansion, significant and equal amounts of 4.8 mm of expansion were observed at the first molar (P 5 0.0000) and the first premolar (P 5 0.0000) levels. The width increase at the first premolar level (20.0%) was significantly greater than that at the first molar level (15.0%) (P 5 0.035). As the primary outcome variable, the cross-sectional airway measured from the posterior nasal spine to basion level was the only parameter showing a significant increase of 99.4 mm2 (59.6%) after rapid maxillary expansion (P 5 0.0004).
Conclusions: These results confirm the findings of previous studies of the effect of rapid maxillary expansion on the maxilla. Additionally, we found that only the cross-sectional area of the upper airway at the posterior nasal spine to basion level significantly gains a moderate increase after rapid maxillary expansion
Interactive Educational Tool for Memory Testing
Memories are one of the most important components in digital systems like SoCs. The high density of their cell array makes memories extremely vulnerable to physical defects. Hence, memory testing and Design-for-Test became one of the crucial tasks in the design of complex and heterogeneous SoCs. Politecnico di Torino and the Institute of Informatics have a wide experience in the field of RAM testing (i.e., automatic march test generation, fault simulators, memory BIST generators etc.). This work is a tentative to put the joint experience of our research groups in developing an interactive educational tool for the students that should introduce standard and well-known methods of memory testing based on BIST. The MemBIST Java Applet and the March Test Generator were two individual tools designed and implemented at the two mentioned institutions. They were merged into one tool in order to facilitate its usage also by the professional
Synthesis and characterization of CaCO3 C biopolymers hybrid nanoporous microparticles for cancer damaged bone therapy
International audienc
Interactive Educational Tool for Memory Testing
Memories are one of the most important components in digital systems like SoCs. The high density of their cell array makes memories extremely vulnerable to physical defects. Hence, memory testing and Design-for-Test became one of the crucial tasks in the design of complex and heterogeneous SoCs.
Politecnico di Torino and the Institute of Informatics have a wide experience in the field of RAM testing (i.e., automatic march test generation, fault simulators, memory BIST generators etc.). This work is a tentative to put the joint experience of our research groups in developing an interactive educational tool for the students that should introduce standard and well-known methods of memory testing based on BIST.
The MemBIST Java Applet and the March Test Generator were two individual tools designed and implemented at the two mentioned institutions. They were merged into one tool in order to facilitate its usage also by the professionals
Indirect Detection of Kaluza-Klein Dark Matter from Latticized Universal Dimensions
We consider Kaluza-Klein dark matter from latticized universal dimensions. We
motivate and investigate two different lattice models, where the models differ
in the choice of boundary conditions. The models reproduce relevant features of
the continuum model for Kaluza-Klein dark matter. For the model with simple
boundary conditions, this is the case even for a model with only a few lattice
sites. We study the effects of the latticization on the differential flux of
positrons from Kaluza-Klein dark matter annihilation in the galactic halo. We
find that for different choices of the compactification radius, the
differential positron flux rapidly converges to the continuum model results as
a function of the number of lattice sites. In addition, we consider the
prospects for upcoming space-based experiments such as PAMELA and AMS-02 to
probe the latticization effect.Comment: 25 pages, 9 figures, LaTeX. Final version published in JCA
X-ray Diffraction and Molecular Dynamics Study of Medium-range Order in Ambient and Hot Water
We have developed x-ray diffraction measurements with high energy-resolution
and accuracy to study water structure at three different temperatures (7, 25
and 66 C) under normal pressure. Using a spherically curved Ge crystal an
energy resolution better than 15 eV has been achieved which eliminates
influence from Compton scattering. The high quality of the data allows a
precise oxygen-oxygen pair correlation function (PCF) to be directly derived
from the Fourier transform of the experimental data resolving shell structure
out to ~12 {\AA}, i.e. 5 hydration shells. Large-scale molecular dynamics (MD)
simulations using the TIP4P/2005 force-field reproduce excellently the
experimental shell-structure in the range 4-12 {\AA} although less agreement is
seen for the first peak in the PCF. The Local Structure Index [J. Chem. Phys.
104, 7671 (1996)] identifies a tetrahedral minority giving the
intermediate-range oscillations in the PCF and a disordered majority providing
a more featureless background in this range. The current study supports the
proposal that the structure of liquid water, even at high temperatures, can be
described in terms of a two-state fluctuation model involving local structures
related to the high-density and low-density forms of liquid water postulated in
the liquid-liquid phase transition hypothesis.Comment: Submitted to Phys. Chem. Chem. Phy
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