756 research outputs found
Upper arch dimensional changes with clear aligners in the early mixed dentition: A prospective study
No full textBackground One goal of orthodontic treatment in mixed dentition is to expand the maxillary arch to allow proper tooth alignment and a correction of sagittal and vertical malocclusions. However, for most treatment protocols, expected outcome is not really clear to allow for a standardization of phase I orthodontic treatments. This lack of information makes it difficult for clinicians to predict tooth movements, including transverse expansion efficacy with Invisalign (R) (Align Technology, Santa Clara, CA, USA) in children. Therefore, the aim of the present study was to evaluate the transverse maxillary arch development with the Invisalign First System (R) in growing subjects.Methods The study group included 23 subjects (9 females, 14 males, mean age 9.4 +/- 1.2 years). Patients were treated nonextraction with Invisalign First System (R) clear aligners with no auxiliaries other than Invisalign (R) attachments. Transverse interdental widths were measured only in the upper arch on each model at the start (T1) and at the end (T2) of treatment. A paired t-test was chosen to compare T2-T1 changes. The level of significance was set at 5%.Results The greatest increase of maxillary width was detected at the level of the upper first deciduous molars (+3.7 +/- 1.4 mm; P < 0.001), followed by the level of the second deciduous molars (+3.4 +/- 1.6 mm; P < 0.001) and by the deciduous canine (+2.6 +/- 2.0 mm; P < 0.001). Upper first molars showed a greater expansion in the intermolar mesial width (+3.2 +/- 1.2 mm; P < 0.001) than in the intermolar distal (+1.7 +/- 1.2 mm; P < 0.001) and transpalatal width (+1.2 +/- 1.2 mm; P < 0.01).Conclusions The Invisalign First System (R) can be considered effective in growing patients who require maxillary arch development. The greatest net increase was detected at the level of upper first deciduous molars, whereas the upper first molars showed a greater expansion in the intermolar mesial width due to a rotation that occurs around its palatal root
Clear aligners in pediatric age in a case of gingival recession due to malocclusion | [Allineatori in età pediatrica in un caso di recessione gengivale dovuta a malocclusione]
No full text
Synchrotron radiation in radiology: radiology techniques based on synchrotron sources
No full textThe characteristics of synchrotron X-ray sources-quite different from those of conventional sources-are exploited by several new imaging techniques. These techniques expand the capabilities of conventional radiology and find interesting application in special cases. We briefly review the basic principle, applications and limitations of the most important of them: monochromatic mammography, two-wavelength digital subtraction angiography, phase-contrast/edge-enhancement imaging, diffraction-enhanced imaging and microtomography.LSELPRXCHU Vaudois, Serv Radiodiagnost & Radiol Intervent, CH-1011 Lausanne, Switzerland. Acad Sinica, Inst Phys, Taipei 11529, Taiwan. Pohang Univ Sci & Technol, Dept Mat Sci, Pohang, South Korea. Ecole Polytech Fed Lausanne, Fac Sci Base, CH-1015 Lausanne, Switzerland. Meuli, R, CHU Vaudois, Serv Radiodiagnost & Radiol Intervent, CH-1011 Lausanne, Switzerland. [email protected] Document Delivery No.: 859O
Clear aligners effects on aesthetics: evaluation of facial wrinkles
No full textBackground: To evaluate the facial aesthetic effects of orthodontic treatment performed with clear aligners and
to compare it to an untreated control group, on lower third facial ageing in adult patients through the use of the
Wrinkle Severity Rating Scale (WSRS) at the beginning (T0) and at the end (T1) of the study period.
Material and Methods: A clear aligners treated group (TG) of 68 patients was compared to a control group of 33
untreated patients (UG). Each group was divided in 2 subgroups according to age: subgroup 1 if under 40 years
of age and subgroup 2 if over. Facial aesthetics of the lower third was evaluated at T0 and T1 by a panel of five
aesthetic experts with WSRS.
Results: Statistically significant changes were found in all subgroups comparing WSRS scores at T0 and T1. The
between group comparisons revealed that wearing clear aligners produces a statistically relevant improvement in
lower third facial aesthetics both in younger (p < 0.05) and older (p < 0.001) patients.
Conclusions: The present retrospective cohort study has successfully shown that malocclusion therapy conducted
through the use of clear aligners in a population of adults affected by dental crowding has beneficial effects on
lower third facial ageing
Hepatic hemangiomas : factors associated with T2 shine-through effect on diffusion-weighted MR sequences
No full textObjectifs:
Déterminer la fréquence et les facteurs prédictifs de l'effet T2 shine-through dans l'hémangiome hépatique.
Matériels et méthodes:
Entre janvier 2010 et novembre 2011, l'imagerie par résonance magnétique du foie de 149 patients avec 388 hémangiomes hépatiques a été revue rétrospectivement. Les caractéristiques lésionnelles: la taille, la localisation, le signal et l'aspect en T1, T2 et en diffusion, l'effet T2 shine-through, le coefficient apparent de diffusion des hémangiomes hépatiques et du foie et type de rehaussement ont été évalués.
Résultats:
L'effet T2 shine-through était observé dans 204/388 (52.6%) des hémangiomes hépatiques et 100 (67.1%) patients. L'ADC moyen des hémangiomas avec T2 shine-through effect était significativement plus bas que les hémangiomas sans T2 shine-through effect (2.0 +/- 0.48 vs 2.38 +/- 0.45 10"3 mm2/s, P < .0001). L'analyse multivariée retrouvait comme facteurs indépendants de la présence d'un effet T2 shine-through un hypersignal sur les images fat- suppressed T2-weighted fast spin-echo, les hémangiomes avec un rehaussement classique et retardé, et l'ADC du foie.
Conclusion:
Le T2 shine-through effect est fréquemment observé dans les hémangiomes hépatiques et dépend des caractéristiques lésionnelles. Sa présence ne remet pas en question le diagnostic lorsque les signes IRM typiques sont présents
A multi-center study: Intra-scan and inter-scan variability of diffusion spectrum imaging
No full textThe objective of this study was to investigate whether it is possible to pool together diffusion spectrum imaging data from four different scanners, located at three different sites. Two of the scanners had identical configuration whereas two did not. To measure the variability, we extracted three scalar maps (ADC, FA and GFA) from the DSI and utilized a region and a tract-based analysis. Additionally, a phantom study was performed to rule out some potential factors arising from the scanner performance in case some systematic bias occurred in the subject study. This work was split into three experiments: intra-scanner reproducibility, reproducibility with twin-scanner settings and reproducibility with other configurations. Overall for the intra-scanner and twin-scanner experiments, the region-based analysis coefficient of variation (CV) was in a range of 1%-4.2% and below 3% for almost every bundle for the tract-based analysis. The uncinate fasciculus showed the worst reproducibility, especially for FA and GFA values (CV 3.7-6%). For the GFA and FA maps, an ICC value of 0.7 and above is observed in almost all the regions/tracts. Looking at the last experiment, it was found that there is a very high similarity of the outcomes from the two scanners with identical setting. However, this was not the case for the two other imagers. Given the fact that the overall variation in our study is low for the imagers with identical settings, our findings support the feasibility of cross-site pooling of DSI data from identical scanners
Mandibular advancement with clear aligners in the treatment of skeletal Class II. A retrospective controlled study
No full textAim The current study aimed to analyse the dentoskeletal effects of the Invisalign mandibular advancement (MA) device in the treatment of skeletal Class II malocclusions. Materials and methods Pre-treatment and post-treatment lateral skull radiographs from patients treated with MA versus TB (Twin-Block Appliance) at the Department of Orthodontics of the University of L’Aquila, Italy, were traced. Eligibility criteria included SNB<78; ANB>4; no previous orthodontic treatments; and vertebral maturation stage (CVM) CS3. Radiographs from patients with craniofacial anomalies, or who underwent extraction treatments, were excluded. Totally, 20 patients were examined, 10 of whom treated with MA and 10 treated with TB. All the radiographs were traced by one expert operator, blind to the groups. A preliminary method error study was performed to exclude intra-operator differences. Results Baseline characteristics of the participants were similar between the groups. Both appliances demonstrated a reduction of SNB and ANB angle, and a decrease in overjet. TB demonstrated a higher efficacy in increasing mandibular dimensions. A significant retroinclination of the upper incisive was observed in the TB group, where a decrease of SNA angles was additionally observed. The resulting differences between the two groups could be attributed to the different design of the appliances. Conclusions The present data show the effectiveness of both TB and MA in the management of skeletal Class II malocclusions due to mandibular retrusion. But some differences exist in the dentoalveolar effect of the two appliances. MA seems indicated in Class II cases where a control of the upper frontal teeth position is needed
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