Upper incisor position in the sagittal plane when smiling. A photographic and CBCT study.

Background: The aim of this study was to analyze the anteroposterior position between the upper incisors (UI) and the soft tissues based on photographs in which the head has been oriented along the Frankfort Horizontal Plane. Material and Methods: Restrospective case-control study carried out by analizing photographic and CBCT images of 109 patientes. The sample was divided into 4 different groups: 21 normocclusive (N), 29 Class II/1st, 29 Class II/2nd y 30 Class III. All patients were positioned using the Frankfurt plane (FH). From this aligned position of the head, a vertical line was drawn perpendicular to the FH passing through the Soft-Tissue Nasion (LN), and the distance in centimeters from of the UI to this vertical line was measured on both the CBCT and the photo of the patient's profile. Results: The UI was located in front of the LN in the groups N, Class II/1st y Class III (0,4, 0,2, 0,1cm respectively) and behind the LN in the group Class II/2nd (0,2cm). There were significant differences between the Class II/2nd and Normocclusive groups and Class II/2nd and Class II/1st (p<0.001 y p=0.004 respectively). Conclusions: Orthodontic and/or surgical correction of various malocclusions can be planned based on the position of the UI with respect to the LN established in Normocclusive patients. Key words:Upper incisors, facial profile, CBCT, photograph, Frankfurt plane, Soft-Tissue Nasion.

Evaluation of the Use of Dual Antiplatelet Therapy beyond the First Year after Acute Coronary Syndrome.

Clinical practice guidelines recommend extending dual antiplatelet therapy (DAPT) beyond 1 year after acute coronary syndrome (ACS) in patients with high ischemic risk and without high bleeding risk. The aim of this study was to identify variables associated with DAPT prolongation in a cohort of 1967 consecutive patients discharged after ACS without thrombotic or hemorrhagic events during the following year. The sample was stratified according to whether DAPT was extended beyond 1 year, and the factors associated with this strategy were analyzed. In 32.2% of the patients, DAPT was extended beyond 1 year. Overall, 770 patients (39.1%) were considered candidates for extended treatment based on PEGASUS criteria and absence of high bleeding risk, and DAPT was extended in 34.4% of them. The presence of a PEGASUS criterion was associated with extended DAPT in the univariate analysis, but not history of bleeding or a high bleeding risk. In the multivariate analysis, a history of percutaneous coronary intervention (odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.4-2.4), stent thrombosis (OR = 3.8, 95% CI 1.7-8.9), coronary artery disease complexity (OR = 1.3, 95% CI 1.1-1.5), reinfarction (OR = 4.1, 95% CI 1.6-10.4), and clopidogrel use (OR = 1.3, 95% CI 1.1-1.6) were significantly associated with extended use. DAPT was extended in 32.2% of patients who survived ACS without thrombotic or hemorrhagic events. This percentage was 34.4% when the candidates were analyzed according to clinical guidelines. Neither the PEGASUS criteria nor the bleeding risk was independently associated with this strategy.

Estudio descriptivo de un brote por SARS-CoV-2 en ancianas de un centro residencial / Descriptive study of an outbreak of SARS-COV-2 in elderly women in a nursing home

Las personas ancianas que viven en las residencias geriátricas son una población de alto riesgo de sufrir importantes consecuencias de la pandemia por SARS-CoV-2, por lo que se analiza una población de ancianas de una institución geriátrica durante la primera ola de la pandemia y se describe el brote epidémico que sufrieron. La población de estudio fue de 157 residentes de una institución geriátrica durante un brote de infección por SARS-CoV-2. Se hizo un estudio prospectivo realizando un seguimiento diario por el equipo del centro de salud. Durante el seguimiento, se realizaron test de PCR para SARS-CoV-2, así como determinación de anticuerpos totales y disgregados. En la población anciana, la sintomatología inespecífica retrasa el diagnóstico y contribuye a la propagación del proceso. Se necesitan pautas de prevención muy estrictas y un control precoz de los casos positivos ya que la pandemia ha demostrado que son en estas residencias donde se produce mayor letalidad. (AU)

The elderly living in nursing homes are a high-risk population who have been negatively impacted by the SARS-CoV-2 pandemic. A population of elderly women from a nursing home was analysed during the first wave of the pandemic, describing the epidemic outbreak they suffered during this first wave. The study population was 157 residents of a geriatric institution during an outbreak of SARS-CoV-2 infection. A prospective study was conducted with daily monitoring by a team from the health centre. During the follow-up, the PCR test for SARS-CoV-2 was performed, as well as a detection of antibodies and disaggregates. In the elderly population, nonspecific symptoms delay a diagnosis and contribute to the spread of the process. Very strict prevention guidelines are needed, along with the early control of positive cases, since the pandemic has shown that it is these residences where the greatest fatality has occurred. (AU)

Accuracy of 18F-FDG PET/CT in patients with the suspicion of cardiac implantable electronic device infections.

BACKGROUND: Utility of 18F-FDG PET/CT in diagnosing infective endocarditis (IE) associated with cardiac implantable electronic devices (CIEDs) is not well established. Current ESC guidelines recommend the use of FDG-PET imaging in patients with CIEDs and positive blood cultures, but the number of studies evaluating the diagnostic performance of FDG-PET imaging in these patients remain limited. Our objective was to assess the diagnostic yield of 18F-FDG PET/CT in patients with suspected CIED infections, differentiating between pocket infection (PI) and lead infection (CIED-IE). METHODS AND RESULTS: From 2013 to 2018, all patients (n = 63) admitted to a hospital with suspected CIED infection were prospectively recruited, undergoing a diagnostic work-up including a PET/CT. Explanted devices and material from the pocket were cultured. 14 cases corresponded to isolated PI and 13 were categorized as CIED-IE. Considering radionuclide uptake in the intracardiac portion of the lead, sensitivity and specificity of PET/CT for CIED-IE were 38.5% and 98.0%, respectively. Positive (19.2) and negative (0.6) likelihood ratio values, suggest that a positive PET/CT is much more probable to correspond to a patient with CIED-IE, whereas it is not possible to exclude this diagnosis when negative. For PI, sensitivity and specificity were 72.2% and 95.6%, respectively. CONCLUSIONS: The yield of 18F-FDG PET/CT for suspected CIED infections differs depending on the site of infection. Due to very high specificity but poor sensitivity, negative studies must be interpreted with caution if the suspicion of CIED-IE is high.

Personalized Repetitive Transcranial Magnetic Stimulation for Primary Progressive Aphasia.

BACKGROUND: Primary progressive aphasia (PPA) is a neurodegenerative syndrome for which no effective treatment is available. OBJECTIVE: We aimed to assess the effect of repetitive transcranial magnetic stimulation (rTMS), using personalized targeting. METHODS: We conducted a randomized, double-blind, pilot study of patients with PPA receiving rTMS, with a subgroup of patients receiving active- versus control-site rTMS in a cross-over design. Target for active TMS varied among the cases and was determined during a pre-treatment phase from a list of potential regions. The primary outcome was changes in spontaneous speech (word count). Secondary outcomes included changes in other language tasks, global cognition, global impression of change, neuropsychiatric symptoms, and brain metabolism using FDG-PET. RESULTS: Twenty patients with PPA were enrolled (14 with nonfluent and 6 with semantic variant PPA). For statistical analyses, data for the two variants were combined. Compared to the control group (n = 7), the group receiving active-site rTMS (n = 20) showed improvements in spontaneous speech, other language tasks, patient and caregiver global impression of change, apathy, and depression. This group also showed improvement or stabilization of results obtained in the baseline examination. Increased metabolism was observed in several brain regions after the therapy, particularly in the left frontal and parieto-temporal lobes and in the precuneus and posterior cingulate bilaterally. CONCLUSION: We found an improvement in language, patient and caregiver perception of change, apathy, and depression using high frequency rTMS. The increase of regional brain metabolism suggests enhancement of synaptic activity with the treatment. TRIAL REGISTRATION: NCT03580954 (https://clinicaltrials.gov/ct2/show/NCT03580954).

Class II subdivision: Cone beam computed tomography- CBCT Analysis.

BACKGROUND: To estimate whether there is skeletal and/or dental asymmetry in class II subdivision patients, between the Class II side and the Class I side using of cone beam computed tomography (CBCT). MATERIAL AND METHODS: A sample of 30 patients, from a private clinic, retrospectively selected; with a class II subdivision diagnosis requiring treatment, who underwent wide-field CBCT that met the inclusion criteria. The data was processed with Dolphin 3D version 11.95 Premium software. The craniometric points, as well as the spatial orientation scheme of the three-dimensional model were proposed by Craig Minich, et al. (1). RESULTS: The Class II subdivision side and the Class I side of each patient were compared through intramaxillary, intramandibular, and intermaxillary measurements, evaluating each one in three dimensions (sagittal, frontal, and axial). Also, the measurements made from the three-dimensional volume, were contrasted with those generated in the biplane views. The level of significance used was 0.05. Statistical analysis was performed using the R program (R Development Core Team), version 3.4.4. The intraoperative variability was previously verified using the Dahlberg formula. This error is 0.35 -1.10, so the spatial orientation and placement of craniometric points are repeatable and reliable. CONCLUSIONS: Statistically significant differences have been found with respect to skeletal values and dentoalveolar position. Regarding the skeletal findings, the class II subdivision side is narrower and there is a shortening of the condylar branch. In the dentoalveolar position on this side, the upper molar and canine are in an advanced position, the lower molar is posterior and lower than the contralateral and the lower canine is in a delayed position. Furthermore, measurements made from a two-dimensional image cannot be extrapolated with those made directly from a three-dimensional volume. The problem is generated by a deviation in dental position as well as an underlying asymmetry. Key words:Class II subdivision, cone beam computed tomography, skeletal asymmetry, dentoalveolar position.

Agreement Between 18F-FDG PET/CT and Whole-Body Magnetic Resonance Compared With Skeletal Survey for Initial Staging and Response at End-of-Treatment Evaluation of Patients With Multiple Myeloma.

PURPOSE: To compare the agreement between whole-body (WB) magnetic resonance (MR) imaging, 18F-FDG PET/CT, and skeletal survey (SS) in patients with multiple myeloma (MM) for diagnosis, initial staging, response evaluation, and early detection of complications. METHODS: This is a retrospective cohort study including MM patients who were diagnosed, treated, and followed in 2 institutions. These patients were studied with SS, WB-MR, and/or 18F-FDG PET/CT. We studied bone lesions by anatomical locations and analyzed the concordance between SS and a tomographic technique (WB-MR or 18F-FDG PET/CT) and between both tomographic techniques (WB-MR and PET/CT). RESULTS: Forty-four MM patients with a mean age of 62.6 years (range, 38-85 years) were included from January 2012 to February 2016. Whole-body MR and 18F-FDG PET/CT found more lesions than SS in every location except in the skull. Concordance between WB-MR and 18F-FDG PET/CT was either good or excellent in most of the locations and in plasmacytoma studies. However, WB-MR was better than 18F-FDG PET/CT in the study of complications (medullar compression and vascular necrosis). CONCLUSIONS: Our results suggest the study of MM patients should include WB-MR and/or 18F-FDG PET/CT, whereas SS is only useful for the skull. Whole-body MR and 18F-FDG PET/CT are complementary techniques, because both of them show good concordance in almost every location. It is still necessary to individualize the indication of each technique according to patient characteristics.

Comparison of condylar position in normal occlusion, Class II Division 1, Class II Division 2 and Class III malocclusions using CBCT imaging.

BACKGROUND: The aim of this study was to establish the condylar position in a group of patients with normal occlusion, compared to Class II Div 1, Class II Div 2 and Class III malocclusions using CBCT imaging. MATERIAL AND METHODS: Retrospective case-control study carried out by analyzing CBCT images of 80 patients. The sample was divided into 4 different groups with 20 patients each (40 TMJ). All patients were positioned using the Frankfurt plane, parallel to the floor and in maximum intercuspation. The control group included asymptomatic patients with normal occlusion (Less than 2mm of tooth size-arch length discrepancy, positive or negative, 0-2mm overjet, 2-4mm overbite, less than 15o rotations, without facial asymmetries, no previous orthodontic or occlusal treatment, without muscular or articular signs or symptoms in both TMJs) and the experimental group with (class II/1, II/2 and III) malocclusions. RESULTS: The group with normal occlusion had the condyles centrally positioned within the glenoid fossa. The values obtained in this group were considered as optimal and when compared with the other groups with malocclusions. The results established that the position of the condyle was more posterior in class II/2 and more superior in class III patients than the asymptomatic normal occlusion group. CONCLUSIONS: The data obtained in the asymptomatic group with normal occlusion could be used as a reference for future studies. The comparison of these values with those obtained from analyzing the different sagittal malocclusions show significant differences that could be valuable when establishing the diagnosis and the objectives of the treatment plan in orthodontics. Key words:Condylar position, CBCT, dental malocclusion and condylar concentricity.

Genetic Algorithms for Optimized Diagnosis of Alzheimer's Disease and Frontotemporal Dementia Using Fluorodeoxyglucose Positron Emission Tomography Imaging.

Genetic algorithms have a proven capability to explore a large space of solutions, and deal with very large numbers of input features. We hypothesized that the application of these algorithms to 18F-Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) may help in diagnosis of Alzheimer's disease (AD) and Frontotemporal Dementia (FTD) by selecting the most meaningful features and automating diagnosis. We aimed to develop algorithms for the three main issues in the diagnosis: discrimination between patients with AD or FTD and healthy controls (HC), differential diagnosis between behavioral FTD (bvFTD) and AD, and differential diagnosis between primary progressive aphasia (PPA) variants. Genetic algorithms, customized with K-Nearest Neighbor and BayesNet Naives as the fitness function, were developed and compared with Principal Component Analysis (PCA). K-fold cross validation within the same sample and external validation with ADNI-3 samples were performed. External validation was performed for the algorithms distinguishing AD and HC. Our study supports the use of FDG-PET imaging, which allowed a very high accuracy rate for the diagnosis of AD, FTD, and related disorders. Genetic algorithms identified the most meaningful features with the minimum set of features, which may be relevant for automated assessment of brain FDG-PET images. Overall, our study contributes to the development of an automated, and optimized diagnosis of neurodegenerative disorders using brain metabolism.

Association of visual and quantitative heterogeneity of 18F-FDG PET images with treatment response in locally advanced rectal cancer: A feasibility study.

BACKGROUND AND PURPOSE: Few tools are available to predict tumor response to treatment. This retrospective study assesses visual and automatic heterogeneity from 18F-FDG PET images as predictors of response in locally advanced rectal cancer. METHODS: This study included 37 LARC patients who underwent an 18F-FDG PET before their neoadjuvant therapy. One expert segmented the tumor from the PET images. Blinded to the patient´s outcome, two experts established by consensus a visual score for tumor heterogeneity. Metabolic and texture parameters were extracted from the tumor area. Multivariate binary logistic regression with cross-validation was used to estimate the clinical relevance of these features. Area under the ROC Curve (AUC) of each model was evaluated. Histopathological tumor regression grade was the ground-truth. RESULTS: Standard metabolic parameters could discriminate 50.1% of responders (AUC = 0.685). Visual heterogeneity classification showed correct assessment of the response in 75.4% of the sample (AUC = 0.759). Automatic quantitative evaluation of heterogeneity achieved a similar predictive capacity (73.1%, AUC = 0.815). CONCLUSION: A response prediction model in LARC based on tumor heterogeneity (assessed either visually or with automatic texture measurement) shows that texture features may complement the information provided by the metabolic parameters and increase prediction accuracy.

Relation of Interatrial Block to Cognitive Impairment in Patients ≥ 70 Years of Age (From the CAMBIAD Case-control Study).

The association between atrial fibrillation, stroke, and interatrial block (IAB) (P-wave duration ≥120 ms) is well recognized, particularly in the case of advanced IAB. We aimed to assess the association of IAB with mild cognitive impairment. Advanced Characterization of Cognitive Impairment in Elderly with Interatrial Block was a case-control multicenter study, conducted in subjects aged ≥70 years in sinus rhythm without significant structural heart disease. Diagnosis of mild cognitive impairment was performed by an expert geriatrician, internist, or neurologist in the presence of changes in cognitive function (Mini Mental State Examination score 20 to 25) without established dementia. A total of 265 subjects were included. Mean age was 79.6 ± 6.3 years and 174 (65.7%) were women; there were 143 cases with mild cognitive impairment and 122 controls with normal cognitive function. Compared with controls, cases had longer P-wave duration (116.2 ± 13.8 ms vs 112.5 ± 13.3 ms, p = 0.028), higher prevalence of IAB (73 [51.0%] vs 38 [31.1%], p = 0.001), higher prevalence of advanced IAB (28 [19.6%] vs 10 [8.2%], p = 0.002), and higher MVP ECG risk score (2.7 ± 1.4 vs 2.2 ± 1.3, p = 0.004). IAB was independently associated with mild cognitive impairment, both for partial (odds ratio 2.0, 95% CI: 1.1 to 3.9) and advanced IAB (odds ratio 2.8, 95% CI: 1.1 to 6.7). In conclusion, in subjects aged ≥70 years without significant structural heart disease, IAB is independently associated with mild cognitive impairment. This association is stronger in the case of advanced IAB.

Amyloid PET findings in multiple sclerosis are associated with cognitive decline at 18 months.

OBJECTIVE: To study the clinical, cognitive, and radiological progression of a cohort of patients with MS, taking into account the amyloid PET with 18F-florbetaben analyses. METHODS: Twenty-nine patients with MS were assessed with longitudinal structural MRI and a clinical and comprehensive neuropsychological protocol, with a mean interval between assessments of 18 ± 3.31 months. 18F-florbetaben PET was performed at baseline. Uptake was analysed in demyelinating plaques (DWM) and normal-appearing white matter (NAWM). Results were correlated with clinical, cognitive and MRI data. RESULTS: Patients with cognitive decline over the follow-up period showed a lower standardised uptake value ratio in NAWM and lower thalamic volume and a higher lesion load in the baseline MRI. Myelin status was correlated with EDSS and cognitive tests mainly evaluating visuospatial function and working memory. Lower uptake in NAWM at baseline was also associated with a growth in white matter lesion volume over time. CONCLUSIONS: Lower white matter uptake in amyloid PET is associated with cognitive decline and an increase in white matter lesion volume during the follow-up. Our study suggests that 18F-florbetaben may be a useful biomarker in assessing myelin status in MS, understanding MS pathophysiology, and predicting cognitive outcomes.

La disfunción de las pequeñas vías aéreas deteriora la calidad de vida de fumadores sin limitación al flujo aéreo / Small Airway Dysfunction Impairs Quality of Life Among Smokers With No Airflow Limitation

Introducción: La disfunción de las pequeñas vías aéreas (DPV) inducida por el tabaco contribuye precozmente a la patogenia de la limitación al flujo aéreo (LFA), aunque resulta poco conocida su repercusión en la percepción de salud. Se pretende evaluar la frecuencia de DPV en fumadores activos sin LFA y comparar la calidad de vida relacionada con la salud (CVRS) de no fumadores, fumadores sin DPV, fumadores con DPV y fumadores con LFA. Métodos: En 53 fumadores activos sin LFA, 20 fumadores con LFA y 20 no fumadores, se utilizaron los cuestionarios SF-36 y EuroQoL y se realizó oscilometría de impulsos, espirometría y determinación de las densidades de atenuación del parénquima pulmonar en inspiración y espiración máximas. Se consideró que existía DPV cuando la resistencia a 5 Hz (R5), la diferencia R5-R20 y el área de reactancia (AX) excedían su límite superior de la normalidad. Resultados: El 35,8% de los fumadores sin LFA tenía DPV. No se detectaron diferencias en los parámetros espirométricos ni la atenuación pulmonar entre los fumadores con o sin DPV y los no fumadores. Sin embargo, los fumadores con DPV presentaban una peor puntuación en los cuestionarios de CVRS que los fumadores sin DPV o los no fumadores, e intermedia a los fumadores con LFA. R5 y X5 fueron identificados como determinantes independientes de la CVRS en los fumadores sin LFA. Conclusiones: La DPV es frecuente en fumadores sin LFA, afectando a un tercio de los mismos, y condicionando de forma independiente su percepción de salud

Introduction: Small airway dysfunction (SAD) caused by smoking contributes to the early onset of airflow limitation (AFL), although its impact on patients’ perception of health is largely unknown. We aimed to evaluate the frequency of SAD in active smokers without AFL, and to compare health-related quality of life (HRQoL) of non-smokers, smokers without SAD, smokers with SAD, and smokers with AFL. Methods: A total of 53 active smokers without AFL, 20 smokers with AFL, and 20 non-smokers completed the SF-36 and EuroQoL questionnaires and performed impulse oscillometry and spirometry. Pulmonary parenchymal attenuation was determined in inspiration and expiration. SAD was determined to exist when resistance at 5Hz (R5), the difference between R5 and R20, and reactance area (AX) exceeded the upper limit of normal. Results: In total, 35.8% of smokers without AFL had SAD. No differences were detected in spirometric parameters or pulmonary attenuation between smokers with or without AFL and non-smokers. However, smokers with SAD had worse scores on HRQoL questionnaires than smokers without SAD or non-smokers, and scores compared to smokers with AFL were intermediate. R5 and X5 were identified as independent determinants of HRQoL in smokers without AFL. Conclusions: SAD is common in smokers without AFL, affecting one third of this population, and independently affecting their perception of health

Small Airway Dysfunction Impairs Quality of Life Among Smokers With No Airflow Limitation. / La disfunción de las pequeñas vías aéreas deteriora la calidad de vida de fumadores sin limitación al flujo aéreo.

INTRODUCTION: Small airway dysfunction (SAD) caused by smoking contributes to the early onset of airflow limitation (AFL), although its impact on patients' perception of health is largely unknown. We aimed to evaluate the frequency of SAD in active smokers without AFL, and to compare health-related quality of life (HRQoL) of non-smokers, smokers without SAD, smokers with SAD, and smokers with AFL. METHODS: A total of 53 active smokers without AFL, 20 smokers with AFL, and 20 non-smokers completed the SF-36 and EuroQoL questionnaires and performed impulse oscillometry and spirometry. Pulmonary parenchymal attenuation was determined in inspiration and expiration. SAD was determined to exist when resistance at 5Hz (R5), the difference between R5 and R20, and reactance area (AX) exceeded the upper limit of normal. RESULTS: In total, 35.8% of smokers without AFL had SAD. No differences were detected in spirometric parameters or pulmonary attenuation between smokers with or without AFL and non-smokers. However, smokers with SAD had worse scores on HRQoL questionnaires than smokers without SAD or non-smokers, and scores compared to smokers with AFL were intermediate. R5 and X5 were identified as independent determinants of HRQoL in smokers without AFL. CONCLUSIONS: SAD is common in smokers without AFL, affecting one third of this population, and independently affecting their perception of health.

Machine learning in the clinical and language characterisation of primary progressive aphasia variants.

INTRODUCTION: Primary progressive aphasia (PPA) is a clinical syndrome of neurodegenerative origin with 3 main variants: non-fluent, semantic, and logopenic. However, there is some controversy about the existence of additional subtypes. Our aim was to study the language and cognitive features associated with a new proposed classification for PPA. MATERIAL AND METHODS: Sixty-eight patients with PPA in early stages of the disease and 20 healthy controls were assessed with a comprehensive language and cognitive protocol. They were also evaluated with 18F-FDG positron emision tomography (PET). Patients were classified according to FDG PET regional metabolism, using our previously developed algorithm based on a hierarchical agglomerative cluster analysis with Ward's linkage method. Five variants were found, with both the non-fluent and logopenic variants being split into 2 subtypes. Machine learning techniques were used to predict each variant according to language assessment results. RESULTS: Non-fluent type 1 was associated with poorer performance in repetition of sentences and reading of irregular words than non-fluent type 2. Conversely, the second group showed a higher degree of apraxia of speech. Patients with logopenic variant type 1 performed more poorly on action naming than patients with logopenic type 2. Language assessments were predictive of PET-based subtypes in 86%-89% of cases using clustering analysis and principal components analysis. CONCLUSIONS: Our study supports the existence of 5 variants of PPA. These variants show some differences in language and FDG PET imaging characteristics. Machine learning algorithms using language test data were able to predict each of the 5 PPA variants with a relatively high degree of accuracy, and enable the possibility of automated, machine-aided diagnosis of PPA variants.

Nonsurgical maxillary expansion in adults: report on clinical cases using the Hyrax expander.

BACKGROUND: Maxillary expansion in adults is object of intense controversy and is still considered an unreliable procedure within the orthodontic community. Therefore, the surgically assisted rapid maxillary expansion is still considered the elective treatment nowadays. The aim of this study is to evaluate the efficacy of a nonsurgical maxillary expansion treatment in adult patients with unilateral or bilateral crossbites and to assess the occurrence of related complications, such as pain and tissue swelling, tipping of the posterior teeth and gingival recessions. METHODS: Maxillary expansion using a Hyrax appliance on the upper first premolars and first molars was performed in 29 patients ranged between 18 and 32 years, mean age of 22±4 years. The sample included 13 patients with unilateral crossbite and 16 with bilateral crossbite. The statistical analysis was carried out using the SPSS Statistics version 23.0. An analysis of the paired data obtained on dental casts before and after treatment was performed using the Student's t-test. RESULTS: The posterior crossbite was fully corrected in all patients. The procedure was well tolerated, and pain, swelling or discomfort was not significant. Statistically significant differences were found between the interdental widths for all pairs, with a P<0.001 for all of them, except in the measurements of canines, in which P=0.001. Measurements of clinical crown height at the beginning (T0) and at the end (T1) of treatment were performed for the same teeth. An increase of the clinical crown height between 0.14 and 0.44 mm was found for premolars and molars. CONCLUSIONS: The results indicate that nonsurgical maxillary expansion in adult patients is an efficient method for correcting transverse deficiency in the maxillary arch. Similarly, the level of complications during treatment was not clinically significant, thus this procedure may be considered a safe treatment.

Inhibition impairment in frontotemporal dementia, amyotrophic lateral sclerosis, and Alzheimer's disease: clinical assessment and metabolic correlates.

The ability to reject an automatic tendency, i.e. inhibition, has been linked to the prefrontal cortex, but its neural underpinnings are still controversial. Neurodegenerative diseases represent an interesting model to explore this issue, given its frequent impairment in these disorders. We investigated the inhibitory impairment and its neural basis using four different tests, which evaluate the presence of inhibitory dysfunction (Stroop test, Hayling test, and two graphical perseveration tests), and assessed their correlation with brain metabolism using 18F-fluorodeoxyglucose positron emission tomography in a group of 76 participants with behavioral variant frontotemporal dementia (bvFTD), Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS) and healthy controls (HC). Inhibition impairment was more frequent in bvFTD and AD, than ALS and HC. AD and bvFTD only differed in the strategy used in Hayling test, and the frequency of impairment in graphical perseveration tests. Correlation between inhibition tests was moderate. The Stroop test correlated with several regions of the frontal and parietal lobes, mainly on the left side. Hayling test correlated with almost all regions of the frontal lobe and, especially, with the orbitofrontal cortex. Some differences in the impaired regions in each disease were found. Inhibition ability was mainly impaired in bvFTD and AD, and it correlated with the bilateral frontal lobe metabolism. There were certain particularities according to the specific task and patients evaluated. These dissimilarities may support the concept of inhibition as a multidimensional construct, with the involvement of common and divergent neural mechanisms.

Clustering Analysis of FDG-PET Imaging in Primary Progressive Aphasia.

Background: Primary progressive aphasia (PPA) is a clinical syndrome characterized by the neurodegeneration of language brain systems. Three main clinical forms (non-fluent, semantic, and logopenic PPA) have been recognized, but applicability of the classification and the capacity to predict the underlying pathology is controversial. We aimed to study FDG-PET imaging data in a large consecutive case series of patients with PPA to cluster them into different subtypes according to regional brain metabolism. Methods: 122 FDG-PET imaging studies belonging to 91 PPA patients and 28 healthy controls were included. We developed a hierarchical agglomerative cluster analysis with Ward's linkage method, an unsupervised clustering algorithm. We conducted voxel-based brain mapping analysis to evaluate the patterns of hypometabolism of each identified cluster. Results: Cluster analysis confirmed the three current PPA variants, but the optimal number of clusters according to Davies-Bouldin index was 6 subtypes of PPA. This classification resulted from splitting non-fluent variant into three subtypes, while logopenic PPA was split into two subtypes. Voxel-brain mapping analysis displayed different patterns of hypometabolism for each PPA group. New subtypes also showed a different clinical course and were predictive of amyloid imaging results. Conclusion: Our study found that there are more than the three already recognized subtypes of PPA. These new subtypes were more predictive of clinical course and showed different neuroimaging patterns. Our results support the usefulness of FDG-PET in evaluating PPA, and the applicability of computational methods in the analysis of brain metabolism for improving the classification of neurodegenerative disorders.