5,885 research outputs found
Comment on Reply to Comment of Finger et al. (2013) on: 'Evidence for an Early-Middle Miocene age of the Navidad Formation (central Chile): Paleontological, paleoclimatic and tectonic implications' of Gutiérrez et al. (2013, Andean Geology 40 (1): 66-78)
Indexación: Web of Science; ScieloIn their answer to our Comment (Finger et al., 2013), Le Roux et al. (2013) misunderstand several of our remarks and present what we view as f lawed arguments, principally their case for a shallow-marine environment for part of the Navidad Formation. We do not wish to see this exchange evolve into an endless discussion, but we feel obligated to clarify some points. We think this is necessary because of history and importance of the Navidad Formation as the reference for the marine Miocene of Chile. Here we also expound upon some concepts relevant to the distinction between shallow-and deep-marine environments
Gingival crevicular fluid alkaline phosphatase activity in relation to pubertal growth spurt and dental maturation: A multiple regression study
Introduction: The identification of the onset of the pubertal growth spurt has major clinical implications when dealing with orthodontic treatment in growing subjects.
Aim: Through multivariate methods, this study evaluated possible relationships between the gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity and pubertal growth spurt and dentition phase.
Materials and methods: One hundred healthy growing subjects (62 females, 38 males; mean age, 11.5±2.4 years) were enrolled into this doubleblind, prospective, cross-sectional-design study. Phases of skeletal maturation (pre - pubertal, pubertal, post - pubertal) was assessed using the cervical vertebral maturation method. Samples of GCF for the ALP activity determination were collected at the mesial and distal sites of the mandibular central incisors. The phases of the dentition were recorded as intermediate mixed, late mixed, or permanent. A multinomial multiple logistic regression model was used to assess relationships of the enzymatic activity to growth phases and dentition phases.
Results: The GCF ALP activity was greater in the pubertal growth phase as compared to the pre - pubertal and post - pubertal growth phases. Significant adjusted odds ratios for the GCF ALP activity for the pre - pubertal and post - pubertal subjects, in relation to the pubertal group, were 0.76 and 0.84, respectively. No significant correlations were seen for the dentition phase.
Conclusions: The GCF ALP activity is a valid candidate as a non - invasive biomarker for the identification of the pubertal growth spurt irrespective of the dentition phase
Radiographic growth indicators: The issue of diagnostic reliability and clinical feasibility
The use of radiographic growth indicators, such as the hand-and-wrist maturation (HWM) and cervical vertebral maturation (CVM)methods, has been recommended in previous clinical trials on the skeletal effects obtained by functional treatment in growing ClassII patients. The concept behind the use of indicators resides in the identification of the pubertal growth spurt in individual patients allowing the delivery of the treatment at this specific stage of skeletal maturation when the mandible response is expected to be maximum growth. Interestingly, while many of the former types of investigations reported a poor correlation between the stages of growth indicators (mainly the CVM) and mandibular growth spurt, most of the latter type of investigations reported clinically relevant favorable effects when the growth indicators are used. It is perhaps that investigations are still missing the relevant piece of evidence.The first critical issue relates to the correlation between two variables (i.e., stages of maturation and mandibular growth) that does not imply diagnostic accuracy, as it has been extensively reported for the case of dental maturation. The other relevant issue relates to the clinical feasibility of the repetition of the recording when dealing with invasive methods based on X-rays, irrespective of whether the methods are accurate. Meanwhile, more opportunity will be given by the use of non-invasive (serum or GCF) biomarkers. According to all these considerations, more reports will be necessary to elucidate the role of the growth indicators in orthodontics fully
Disc Displacement with Intermittent Lock: A Case Series of a Rarely-addressed Disorder
Aim: We describe a series of five cases presented with disc displacement with reduction and intermittent lock (DDwRIL), from presentation to follow-up. Background: Disc displacement with reduction with intermittent lock is a temporomandibular disorder in which the disc is displaced and reduced, along with temporary locking leading to limited opening. Due to the fact that it has only been recognized as a separate disease in 2013, there is no clear guideline on the management of these cases. Cases descriptions: We present five cases of clinically established DDwRIL in different age groups. We walk through clinical presentation and diagnostic workup. Several modalities were used in the management of described cases from noninterventional management with counselling only to physical and splint therapies. Conclusion: Disc displacement with reduction, with intermittent locking is a challenging temporomandibular disorder with risk to progress into disc displacement without reduction and hence necessitates a tailored approach and long-term follow-up. Clinical significance: To our knowledge, this is the first case series reported on DDwRIL which provides detailed clinical presentation, examination, management, and discussion for orofacial pain practitioners as well as for future studies on this disease
Gingival crevicular fluid protein content and alkaline phosphatase activity in relation to pubertal growth phase
OBJECTIVE: To evaluate gingival crevicular fluid (GCF) protein content and alkaline phosphatase (ALP) activity in growing subjects in relation to stages of skeletal maturation, ie, the growth phase, as prepubertal, pubertal, and postpubertal. SUBJECTS AND METHODS: Fifty healthy growing subjects (31 girls and 19 boys; age range, 7.8–17.7 years) were enrolled in this study that followed a double-blind, prospective, cross-sectional design. Collection of GCF was performed at the mesial and distal sites of both central incisors, for the maxilla and mandible. Growth phase was assessed through the cervical vertebral maturation method. GCF parameters were expressed as total protein content, total ALP activity, and normalized ALP activity. RESULTS: The total GCF protein content was similar between the different growth phases. On the contrary, the total ALP activity showed a peak for the pubertal growth phase. The normalized GCF ALP activity was only poorly associated with growth phase. No differences were seen between the maxillary and mandibular sites, or between the sexes, for any GCF parameter. CONCLUSIONS: The total GCF protein content is not sensitive to the growth phase. However, GCF ALP activity has potential as a diagnostic aid for identification of the pubertal growth phase in individual subjects when expressed as total, but not normalized, values
Extracciones dentarias en pacientes en tratamiento con anticoagulantes: revisión de la literatura
Objetivo del trabajo. En pacientes en terapia con anticoagulantes orales, una simple extracción puede provocar hemorragias importantes. En la literatura se describen dos enfoques terapéuticos en casos de intervenciones quirúrgicas en esta categoría de pacientes. Uno propone la reducción de la dosis terapéutica del fármaco, mientras que el segundo sugiere la sustitución con heparina. El objetivo de este trabajo es revisar la literatura que trata este tema con el fin de obtener un protocolo ideal. Conclusiones. En caso de extracciones simples es suficiente usar anestesia con vasoconstrictor (en el caso de que no haya otras contraindicaciones), realizar suturas bien tensadas, aplicar coadyuvantes hemostáticos locales y ácido tranexámico tópico. Solo en casos de intervenciones más complejas, o con valores de INR mayores a 3,5, será necesario reducir la dosis del fármaco y consecuente sustitución con heparina de acuerdo a las instrucciones del hematólogo y del cardiólogo. Aim of the work. In patients treated with oral anticoagulants, even simple tooth extractions can produce large hemorrhages. There are two main therapeutic outlines suggested in literature in case of little oral surgery. The first one is based on the reduction of the therapeutic dose of the drug, and the second one on the substitution with heparin. The aim of this paper was to review the.literature on the management of patients treated with anticoagulants in order to obtain univocal guidelines. Conclusion. In case of simple tooth extractions generally a vasoconstrictive anaesthetic (if there are no other contraindications), tight sutures, the application of hemostats and tronexamic acid are enough. Only in case of more complex surgery or of INR values higher than 3,5 it is necessory to reduce the anticoagulant dose or to change the therapy with heparin, if agreed by the hoemotologist and/ or the cardiologist
Outcome stability of orthopaedic treatment of skeletal Class III malocclusion: A study of prognostic agreement between three models
Introduction: Long-term stability of the treatment outcome of skeletal Class III malocclusion is always not achievable, thereforeseveral prediction models of stability of orthopaedic treatment of the Class III malocclusion have been proposed.
Aim: This cross-sectional study was aimed at the evaluation of the prognostic agreement and association between three differentprediction models based on skeletal parameters recorded on lateral cephalograms.
Materials and methods: A total of 75 subjects (34 females and 41 males, age range 7-11, mean age 9.1±1.2years) having skeletal ClassIII malocclusion were included in the study. Prediction models reported by Baccetti et al. 2004 (prediction model 1), Moon et al.2005 (prediction model 2) and Yoshida et al. 2006 (prediction model 3), were considered. Percentage agreement and unweighted kappa coefficient evaluated the agreement between the prediction models in terms of stable or unstable cases. Multiple regressions were run to evaluate the association between the absolute scores obtained from each of the prediction model (prediction scores).
Results: Percentage agreement ranged from 77.3% (models 2 and 3) to 89.3%, (models 1 and 2) and corresponding unweighted kappa coefficients ranged from 0.099 (models 1 and 3) to 0.205 (models 2 and 3). The prediction score from model 3 was significantly associated with those from both the other models; on the contrary, prediction scores from models 1 and 2 were not significantly associated.
Conclusions: Agreement in terms of stability or instability outcome derived from these models is only partial and not satisfactory,even though significant association between the prediction scores denotes a common biological meaning of the models
Treatment effects of fixed functional appliances alone or in combination with multibracket appliances: A systematic review and meta-analysis
"Abstract Objective: To assess skeletal and dentoalveolar effects of fixed
functional appliances, alone or in combination with multibracket appliances
(comprehensive treatment), on Class II malocclusion in pubertal and postpubertal patients. Materials and Methods: Literature survey was conducted using the Medline, SCOPUS, LILACS, and SciELO databases and The Cochrane Library, and through a manual search. The studies retrieved had to have a matched untreated control group. No restrictions were set regarding the type of fixed appliance, treatment length, or to the cephalometric analysis used. Data extraction was mostly predefined at the protocol stage by two authors. Supplementary mandibular elongation was used for the meta-analysis. Results: Twelve articles qualified for the final analysis of which eight articles were on pubertal patients and four were on postpubertal patients. Overall supplementary total mandibular longationsas mean (95 confidence interval) were 1.95 mm (1.47 to 2.44) and 2.22 mm (1.63to 2.82) among pubertal patients and -1.73 mm (-2.60 to -0.86) and 0.44 mm (-0.78 to 1.66) among postpubertal patients, for the functional and comprehensive treatments, respectively. For pubertal subjects, maxillary growth restraint was also reported. Nevertheless, skeletal effects alone would not account for the whole Class II correction even in pubertal subjects with dentoalveolar effects always present. Conclusions: Fixed functional treatment is effective in treating Class II malocclusion with skeletal effects when performed during the pubertal growth phase, very few data are available on postpubertal patients.
Can differences in the nickel abundance in Chandrasekhar mass models explain the relation between brightness and decline rate of normal Type Ia Supernovae?
The use of Type Ia supernovae as distance indicators relies on the
determination of their brightness. This is not constant, but it can be
calibrated using an observed relation between the brightness and the properties
of the optical light curve (decline rate, width, shape), which indicates that
brighter SNe have broader, slower light curves. However, the physical basis for
this relation is not yet fully understood. Among possible causes are different
masses of the progenitor white dwarfs or different opacities in
Chandrasekhar-mass explosions. We parametrise the Chandrasekhar-mass models
presented by Iwamoto et al (1999), which synthesize different amounts of Ni,
and compute bolometric light curves and spectra at various epochs. Since
opacity in SNe Ia is due mostly to spectral lines, it should depend on the mass
of Fe-peak elements synthesized in the explosion, and on the temperature in the
ejecta. Bolometric light curves computed using these prescriptions for the
optical opacity reproduce the relation between brightness and decline rate.
Furthermore, when spectra are calculated, the change in colour between maximum
and two weeks later allows the observed relation between M_B(Max) and
Dm_{15}(B) to be reproduced quite nicely. Spectra computed at various epochs
compare well with corresponding spectra of spectroscopically normal SNeIa
selected to cover a similar range of Dm_{15}(B) values.Comment: 25 pages, including 6 figures. Accepted for publication in Ap
Low Arousal Threshold Estimation Predicts Failure of Mandibular Advancement Devices in Obstructive Sleep Apnea Syndrome
Introduction: The treatment of choice for obstructive sleep apnea syndrome (OSAS) is continuous positive airway pressure (CPAP). However, CPAP is usually poorly tolerated and mandibular advancement devices (MADs) are an alternative innovative therapeutic approach. Uncertainty still remains as to the most suitable candidates for MAD. Herein, it is hypothesized that the presence of low arousal threshold (low ArTH) could be predictive of MAD treatment failure.
Methods: A total of 32 consecutive patients, with OSAS of any severity, who preferred an alternate therapy to CPAP, were treated with a tailored MAD aimed at obtaining 50% of their maximal mandibular advancement. Treatment response after 6 months of therapy was defined as AHI 58.3%.
Results: There were 25 (78.1%) responders (p-value < 0.01) at 6 months. Thirteen patients (40.6%) in the non-severe group reached AHI lower than 5 events per hour. MAD treatment significantly reduced the median AHI in all patients from a median value of 22.5 to 6.5 (74.7% of reduction, p-value < 0.001). The mandibular advancement device reduced AHI, whatever the disease severity. A significant higher reduction of Delta AHI, after 6 months of treatment, was found for patients without low ArTH.
Conclusions: Low ArTH at baseline was associated with a poorer response to MAD treatment and a lower AHI reduction at 6 months. A non-invasive assessment of Low ArTH can be performed through the Edwards' score, which could help to identify an endotype with a lower predicted response to oral appliances in a clinical setting
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