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.

Different apathy clinical profile and neural correlates in behavioral variant frontotemporal dementia and Alzheimer's disease.

OBJECTIVES: Apathy is one of the most common and disabling syndromes of dementia. Clinical apathy expression and neuroanatomical basis of apathy seem to differ between behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD), although evidence is scarce and poorly understood. Our main purposes were to compare the clinical apathy profile from patients with bvFTD and AD and analyze the relationship between apathy and brain metabolism measured using positron emission tomography imaging with 18 F fluorodeoxyglucose (FDG-PET). METHODS: Forty-two bvFTD, 42 AD, and 30 healthy volunteers without cognitive or behavioral complaints were included. Apathy was defined using Robert's 2009 diagnostic criteria, and specific apathy characteristics were assessed with the Lille Apathy Rating Scale. All participants underwent FDG-PET brain scan to provide data for voxel-based morphometric analysis. RESULTS: Multivariate analysis showed that subjects affected by bvFTD displayed greater impairment of emotional apathy and self-awareness in comparison with AD sample. Additionally, FDG-PET imaging analyses revealed that apathy was associated with different neuroanatomical substrates in each dementia group: left lateral prefrontal, medial frontal/anterior cingulate, lateral orbitofrontal and anterior insular cortices in bvFTD, and right anterior cingulate in AD. CONCLUSIONS: These results support that apathy is a complex syndrome, with different clinical expressions across different pathological conditions. Those differences in qualitative aspects of apathy seem to be associated with differences in the damage sites, as shown by our FDG-PET imaging analysis. Our findings provide a better knowledge about pathophysiology of apathy in dementia, which could have practical implications for therapeutic management. Copyright © 2017 John Wiley & Sons, Ltd.

Neural Basis of Cognitive Assessment in Alzheimer Disease, Amnestic Mild Cognitive Impairment, and Subjective Memory Complaints.

INTRODUCTION: Interpreting cognitive tests is often challenging. The same test frequently examines multiple cognitive functions, and the functional and anatomical basis underlying test performance is unknown in many cases. This study analyses the correlation of different neuropsychological test results with brain metabolism in a series of patients evaluated for suspected Alzheimer disease. METHODS: 20 healthy controls and 80 patients consulting for memory loss were included, in which cognitive study and 18F-fluorodeoxyglucose PET were performed. Patients were categorized according to Reisberg's Global Deterioration Scale. Voxel-based analysis was used to determine correlations between brain metabolism and performance on the following tests: Free and Cued Selective Reminding Test (FCSRT), Boston Naming Test (BNT), Trail Making Test, Rey-Osterrieth Complex Figure test, Visual Object and Space Perception Battery (VOSP), and Tower of London (ToL) test. RESULTS: Mean age in the patient group was 73.9 ± 10.6 years, and 47 patients were women (58.7%). FCSRT findings were positively correlated with metabolism in the medial and anterior temporal region bilaterally, the left precuneus, and posterior cingulate. BNT results were correlated with metabolism in the middle temporal, superior, fusiform, and frontal medial gyri bilaterally. VOSP results were related to the occipital and parietotemporal regions bilaterally. ToL scores were correlated to metabolism in the right temporoparietal and frontal regions. CONCLUSIONS: These results suggest that different areas of the brain are involved in the processes required to complete different cognitive tests. Ascertaining the functional basis underlying these tests may prove helpful for understanding and interpreting them.

Metabolic and molecular relative percentage coreduction in patients with locally advanced rectal cancer treated with neoadjuvant therapy.

PURPOSE: Vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor-1 (EGFR) and cyclooxygenase-2 (COX-2) stimulate key processes involved in tumour progression and are important targets for cancer therapeutics. (18)F-FDG maximum standardized uptake value (SUVmax) on PET/CT is a marker of tumour metabolic activity. The purpose of this study was to measure percentage reductions in SUVmax (∆SUVmax%), VEGFR-2 (∆VEGFR-2%), EGFR (∆EGFR%) and COX-2 (∆COX-2%) in patients with locally advanced rectal cancer (LARC) after preoperative treatment, and to correlate the changes in these markers of response with pathological response in terms of tumour regression grade (TRG) using Rödel's scale and long-term clinical outcome. METHODS: VEGFR-2, EGFR and COX-2 were measured using a quantitative and qualitative compound immunohistochemistry analysis (immunoreactive score) of the pretreatment endoscopic biopsy and definitive surgical specimens. Composite indexes using ∆SUVmax% and the three molecules were developed to differentiate patients with metabolic and molecular responses from nonresponders. Cox proportional hazards model was used to explore associations between the tumour markers, disease-free survival (DFS) and overall survival (OS). RESULTS: The analysis included 38 patients with a median follow-up of 86 months (range 5 - 113 months). The ∆VEGFR-2%/∆SUVmax% index correctly identified 13 of 19 pathological responders (TRG 3 and 4) and 17 of 19 nonresponders (TRG 0 - 2) (sensitivity 68 %, specificity 89 %, accuracy 79 %, positive predictive value 87 %, negative predictive value 74 %). In multivariate analysis, only the ∆VEGFR-2%/∆SUVmax% index was associated with DFS (HR 0.11, p = 0.001) and OS (HR 0.15, p = 0.02). CONCLUSION: In patients with LARC the ∆VEGFR-2%/∆SUVmax% response index is associated with outcome. Determination of the optimal diagnostic cut-off level for this novel biomarker association should be explored. Evaluation in a clinical trial is required to determine whether selected patients could benefit from treatment with a VEGFR-targeted therapeutic agent.

Amyloid- and FDG-PET imaging in amyotrophic lateral sclerosis.

PURPOSE: We aimed to study brain metabolism and presence of beta-amyloid deposits using positron emission tomography (PET) in patients with amyotrophic lateral sclerosis (ALS). METHODS: This prospective cross-sectional study included 18 patients with definite or probable ALS according to the revised El Escorial diagnostic criteria, and 24 healthy controls. Patients underwent neurological and neuropsychological assessments, PET with (18)F-fluorodeoxyglucose (FDG), and amyloid-PET with (18)F-florbetaben. RESULTS: Patients with ALS showed hypometabolism in the frontal area and hypermetabolism in the cerebellum compared to healthy controls. Four patients (22 %) displayed cognitive impairment and decreased metabolism in the frontal area extending bilaterally to the parietal regions, and increased metabolism in the posterior area of the cerebellum. In patients with no cognitive impairment, metabolism was lower in the left superior frontal gyrus and higher in the anterior and posterior lobes of the cerebellum. In the individual analysis, six patients (35 %) displayed more anterior involvement with hypometabolism affecting the superior frontal, medial, and inferior gyri; six patients (35 %) exhibited a more posterior pattern with hypometabolism in the precentral and postcentral gyri and in the superior and inferior parietal lobules; two patients (11 %) showed a mixed pattern; and three patients (17 %) showed no alterations in brain metabolism. Three (16 %) showed increased (18)F-florbetaben uptake compared to controls. CONCLUSIONS: We have identified two main patterns of brain metabolism with an association to cognitive status. Only a subgroup of patients showed an increased uptake of the amyloid tracer. Our results suggest that ALS is heterogeneous from a clinical, metabolic, and molecular standpoint.

Human cytomegalovirus and Epstein-Barr virus infection impact on (18)F-FDG PET/CT SUVmax, CT volumetric and KRAS-based parameters of patients with locally advanced rectal cancer treated with neoadjuvant therapy.

PURPOSE: It has long been debated whether human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) are associated with rectal cancer. The gene products of HCMV and EBV contribute to cell-cycle progression, mutagenesis, angiogenesis and immune evasion. The aim of this prospective study was to analyse the association between infection of a tumour by HCMV and EBV and clinical, histological, metabolic ((18)F-FDG uptake), volumetric (from CT) and molecular (KRAS status) features and long-term outcomes in a homogeneously treated group of patients with locally advanced rectal cancer. METHODS: HCMV and EBV were detected in pretreatment biopsies using polymerase chain reaction (PCR). The Cox proportional hazards regression model was used to explore associations between viral infection and disease-free survival (DFS) and overall survival (OS). RESULTS: We analysed 37 patients with a median follow-up of 74 months (range 5-173 months). Locoregional control, OS and DFS at 5 years were 93%, 74% and 71%, respectively. Patients with HCMV/EBV coinfection had a significantly higher maximum standardized uptake value than patients without viral coinfection (p = 0.02). Significant differences were also observed in staging and percentage relative reduction in tumour volume between patients with and without HCMV infection (p < 0.01) and EBV infection (p < 0.01). KRAS wildtype status was significantly more frequently observed in patients with EBV infection (p <0.01) and HCMV/EBV co-infection (p = 0.04). No significant differences were observed in OS or DFS between patients with and without EBV infection (p = 0.88 and 0.73), HCMV infection (p = 0.84 and 0.79), and EBV/CMV coinfection (p = 0.24 and 0.39). CONCLUSION: This pilot study showed that viral infections were associated with metabolic staging differences, and differences in the evolution of metabolic and volumetric parameters and KRAS mutations. Further findings of specific features will help determine the best candidates for metabolic and volumetric staging and restaging. Further toxicity profile findings will help to determine the best candidates for specific supportive treatment during pelvic chemoradiotherapy in patients with locally advanced rectal cancer.

Visual and statistical analysis of ¹8F-FDG PET in primary progressive aphasia.

PURPOSE: Diagnosing progressive primary aphasia (PPA) and its variants is of great clinical importance, and fluorodeoxyglucose (FDG) positron emission tomography (PET) may be a useful diagnostic technique. The purpose of this study was to evaluate interobserver variability in the interpretation of FDG PET images in PPA as well as the diagnostic sensitivity and specificity of the technique. We also aimed to compare visual and statistical analyses of these images. METHODS: There were 10 raters who analysed 44 FDG PET scans from 33 PPA patients and 11 controls. Five raters analysed the images visually, while the other five used maps created using Statistical Parametric Mapping software. Two spatial normalization procedures were performed: global mean normalization and cerebellar normalization. Clinical diagnosis was considered the gold standard. RESULTS: Inter-rater concordance was moderate for visual analysis (Fleiss' kappa 0.568) and substantial for statistical analysis (kappa 0.756-0.881). Agreement was good for all three variants of PPA except for the nonfluent/agrammatic variant studied with visual analysis. The sensitivity and specificity of each rater's diagnosis of PPA was high, averaging 87.8 and 89.9% for visual analysis and 96.9 and 90.9% for statistical analysis using global mean normalization, respectively. In cerebellar normalization, sensitivity was 88.9% and specificity 100%. CONCLUSION: FDG PET demonstrated high diagnostic accuracy for the diagnosis of PPA and its variants. Inter-rater concordance was higher for statistical analysis, especially for the nonfluent/agrammatic variant. These data support the use of FDG PET to evaluate patients with PPA and show that statistical analysis methods are particularly useful for identifying the nonfluent/agrammatic variant of PPA.

Amyloid PET imaging in multiple sclerosis: an (18)F-florbetaben study.

BACKGROUND: Positron emission tomography (PET) images with amyloid tracers show normal uptake in healthy white matter, which suggests that amyloid tracers are potentially useful for studying such white matter diseases as multiple sclerosis (MS). METHODS: Twelve patients diagnosed with MS (5 with RRMS, 5 with SPMS, and 2 with PPMS) and 3 healthy controls underwent studies with MRI and (18)F-florbetaben-PET imaging. Images were preprocessed using Statistical Parametric Mapping software. We analysed (18)F-florbetaben uptake in demyelinating plaques (appearing as hyperintense lesions in FLAIR sequences), in normal-appearing white matter, and in grey matter. RESULTS: Mean standardized uptake value relative to cerebellum was higher in normally appearing white matter (NAWM) (1.51 ± 0.12) than in damaged white matter (DWM) (1.24 ± 0.12; P = .002). Mean percentage of change between NAWM and DWM was -17.56% ± 6.22%. This percentage of change correlated negatively with EDSS scores (r = -0.61, p < .05) and with age (r = -0.83, p < 0.01). Progressive forms of MS showed a more pronounced reduction of the uptake in DWM in comparison to relapsing-remitting form. CONCLUSIONS: Uptake of (18)F-florbetaben in damaged white matter is lower than that occurring in normally-appearing white matter. These findings indicate that amyloid tracers may be useful in studies of MS, although further research is needed to evaluate the utility of amyloid-PET in monitoring MS progression.

Evaluation of the new consensus criteria for the diagnosis of primary progressive aphasia using fluorodeoxyglucose positron emission tomography.

BACKGROUND: New consensus criteria have been proposed to classify primary progressive aphasia (PPA) into three variants: agrammatic, semantic, and logopenic. Some studies have subsequently addressed the usefulness of these criteria, with controversial results. We aimed to determine the correlation between the clinical diagnosis according to the new criteria and brain topography in (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET). METHODS: Patients meeting the PPA criteria were prospectively recruited in a single center during a period of 18 months. They were clinically classified according to the new criteria and underwent FDG-PET. The cerebral metabolism of each patient was compared to a healthy control group using statistical parametric mapping. The expected variant according to the analysis of PET imaging was compared with the clinical diagnosis using the consensus criteria. RESULTS: 32 patients were included. 90% of them fulfilled the consensus criteria and could be classified into one of the three clinical variants. The correlation with the cerebral metabolism was high: the kappa index was 0.91 in the agrammatic variant, 0.71 in the semantic variant, and 0.74 in the logopenic variant. CONCLUSIONS: A high correlation with the diagnosis obtained using FDG-PET was found. However, an overdiagnosis of the logopenic variant was observed. These results support the use of the new criteria, but some modifications or complementary studies may still be necessary.

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.

¹8F-FDG PET/CT-based treatment response evaluation in locally advanced rectal cancer: a prospective validation of long-term outcomes.

PURPOSE: To prospectively evaluate the usefulness of (18)F-FDG PET/CT) imaging for predicting histopathological response and long-term clinical outcomes in locally advanced rectal cancer (LARC). METHODS: This prospective study included 38 patients with a confirmed diagnosis of LARC (cT3-4 or cN+) who underwent (18)F-FDG PET/CT before and after neoadjuvant therapy (NAT). Total mesorectal excision was scheduled 6 weeks after NAT and was followed by an expert histopathological analysis of the surgical specimen. Baseline variables and previously identified maximum FDG standardized uptake value (SUVmax) cut-off values before NAT (SUVmaxPRE ≥6) and after NAT (SUVmaxPOST ≥2), and the absolute and percentage reductions from baseline SUVmax (∆SUVmax <4 and ∆SUVmax% <65 %, respectively) were applied to differentiate patients showing a metabolic tumour response from nonresponders. These features were correlated with tumour regression grade (TRG), disease-free survival (DFS) and overall survival (OS). RESULTS: Significantly higher 5-year DFS and OS were seen in 19 responders (TRG 3 or 4) than in 19 nonresponders (TRG 0-2; 94.4 vs. 48.8 %, p = 0.001; 94.7 vs. 63.2 %, p = 0.02, respectively). In multivariate analysis the only PET/CT SUVmax-based parameter significantly correlated with the likelihood of recurrence and survival was ∆SUV% <65 % (HR = 5.95, p = 0.02, for DFS; HR = 5.26, p = 0.04, for OS) CONCLUSION: This prospective study proved that (18)F-FDG PET/CT is a valuable imaging tool for assessing rectal cancer TRG and long-term prognosis, and could potentially serve as an intermediate endpoint in treatment optimization research and rectal cancer patient care.

Clinical significance of VEGFR-2 and ¹8F-FDG PET/CT SUVmax pretreatment score in predicting the long-term outcome of patients with locally advanced rectal cancer treated with neoadjuvant therapy.

PURPOSE: Vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor-1 (EGFR), and cyclooxygenase-2 (COX-2) stimulate key processes involved in tumor progression and are important targets for cancer drugs. (18)F-FDG maximum standardized uptake value (SUVmax) is a marker of tumor metabolic activity. The purpose of this study was to measure SUVmax combined with VEGFR-2, EGFR and COX-2 proteins in pretreatment tumor biopsies from patients with locally advanced rectal cancer receiving intensive neoadjuvant treatment and to correlate the findings with clinical outcome. METHODS: VEGFR-2, EGFR and COX-2 were measured using the immunoreactive score (IRS). SUVmax (median 8.4) was quantified in tumors with molecular overexpression (IRS ≥3 + SUVmax ≥ 8.4 indicating active tumors; SUVmax <8.4 indicating inactive tumors). The Cox proportional hazards model was used to explore associations between tumor markers, disease-free survival (DFS) and overall survival (OS). RESULTS: The study group comprised 38 patients with a median follow-up of 69.3 months (range 4.5 - 92 months). Multivariate analysis showed that active tumors (overexpressing VEGFR-2, high SUVmax) were associated with worse DFS (HR 4.73, 95 % CI 1.18 - 22.17; p = 0.04) and OS (HR 4.28, 95 % CI 1.04 - 20.12; p = 0.05). CONCLUSION: Active tumors overexpressing VEGFR-2 are associated with a worse overall outcome in patients with rectal cancer treated with induction chemotherapy followed by pelvic chemoradiation and surgery. The optimal diagnostic cut-off level for this novel biomarker association should be investigated. Evaluation in a clinical trial is required to determine whether selected patients could benefit from a VEGFR-targeting drug.

A multicentre randomized trial of combined individual and telephone counselling for smoking cessation.

OBJECTIVE: The present study assessed the effectiveness of smoking cessation programs combining individual and telephone counselling, compared to individual or telephone counselling alone. METHOD: A randomized, multicentre, open-label trial was performed between January 2009 and July 2011 at six smoking cessation clinics in Spain. Of 772 smokers assessed for eligibility, 600 (77%) met inclusion criteria and were randomized. Smokers were randomized to receive individual counselling, combined telephone and individual counselling, or telephone counselling. The primary outcome was biochemically validated continuous abstinence at 52 weeks. RESULTS: The 52-week abstinence rate was significantly lower in the telephone group compared to the combined group (20.1% vs. 29.0%; OR, 1.32; 95% CI, 1.1-2.7) and to the individual counselling group (20.1% vs. 27.9%; OR, 1.37; 95% CI, 1.0-2.8). The 52-week abstinence rates were not significantly higher in the combined group than the individual group (OR, 0.97; 95% CI, 0.7-1.4). CONCLUSION: Individual counselling and combined individual and telephone counselling were associated with higher 52-week abstinence rates than telephone counselling alone. A combined approach may be highly useful in the clinical treatment of smokers, as it involves less clinic visits than individual counselling alone, thus reducing the program cost, and it increases patient compliance compared to telephone counselling alone.

The segmented arch approach: a method for orthodontic treatment of a severe Class III open-bite malocclusion.

An open bite is a common malocclusion, and it is generally associated with several linked etiologic factors. When establishing the treatment plan, it is essential to consider every aspect of the various etiologic causes and their evolution; this will help to correct it. This article reports the case of a girl aged 10.7 years with a skeletal Class III malocclusion and an open bite. The treatment mechanics were based on compensatory dental changes performed to close the bite and correct the skeletal Class III malocclusion. The patient had a deep maxillary deficiency, and the lower facial third was severely enlarged. In this article, we aimed to describe a simple mechanical approach that will close the bite through changes in the occlusal plane (segmentation of arches). It is an extremely simple method that is easily tolerated by the patient. It not only closes the bite effectively but also helps to correct the unilateral or bilateral lack of occlusal interdigitation between the dental arches. A Class III patient with an anterior open bite is shown in this article to illustrate the effectiveness of these treatment mechanics.

Effect of temperature on the orthodontic clinical applications of NiTi closed-coil springs.

UNLABELLED: NiTi spring coils were used to obtain large deformation under a constant force. The device consists on a NiTi coil spring, superelastic at body temperature, in order to have a stress plateau during the austenitic retransformation during the unloading. The temperature variations induced changes in the spring force. OBJECTIVES: The aim of this study is to investigate the effect of the temperature variations in the spring forces and corrosion behaviour simulating the ingestion hot/cold drinks and food. STUDY DESIGN: The springs were subjected to a tensile force using universal testing machine MTS-Adamel (100 N load cell). All tests were performed in artificial saliva maintained at different temperatures. The corrosion tests were performed according to the ISO-standard 10993-15:2000. RESULTS: The increase in temperature of 18 °C induced an increase in the spring force of 30%. However, when the temperature returns to 37 °C the distraction force recovers near the initial level. After cooling down the spring to 15 °C, the force decreased by 46%. This investigation show as the temperature increase, the corrosion potential shifts towards negative values and the corrosion density is rising. CONCLUSIONS: The changes of the temperatures do not modify the superelastic behaviour of the NiTi closed-coil springs. The corrosion potential of NiTi in artificial saliva is decreasing by the rise of the temperatures.

Lower incisor position in different malocclusions and facial patterns.

INTRODUCTION: The position of lower incisor has been of considerable concern when planning an orthodontic treatment, having been recognized as one of diagnostic keys, Very important in the development of malocclusion and facial pattern. OBJECTIVES: In this study we claim to determine the importance of the position and inclination of lower incisor in the different malocclusions and facial patterns, and to base which of the cephalometric measurement parameters are the mostreliable. Material and methods. Ninety lateral radiographies were taken, and they were classified by skeletal malocclusion and facial pattern.These teleradiographies have been performed cephalometric analysis, which includelower incisor position belong the following analysis: Ricketts, Riolo, Tweed, McHorris, Jarabak-MSE and Holdaway. STUDY DESIGN: Cross-sectional study where we perform statistical analysis Anova test, Pearson correlations and Bonferroni analysis. Results. The analyzed measurements present a statistically significant differentiation in lower incisor inclination respect to the anterior cranial base, McHorris angle, angulation of lower incisor respect to occlusal plane and mandibular plane. CONCLUSIONS: There are statistically significant differentiation in lower incisor position and inclination respect the malocclusion and individual facial pattern.

Improvement in adhesion of the brackets to the tooth by sandblasting treatment.

In oral orthodontic treatments, achievement of a good adhesion between brackets and teeth surfaces is essential. One way to increase adhesion is to apply a surface treatment of teeth facing surfaces through the projection of abrasive particles to produce a surface roughness which improves adhesion of the bracket to the tooth, because of the significantly increased contact between the two surfaces. The effect on adhesion through the use of this technique in different types of brackets, as well as through the use of different blasting particles, however, is yet not well described. In this study we have included three types of brackets which are commonly used in orthodontic therapies (two of them a mesh-type and the third one a micro-milled type) with a contact surface area of 11.16, 8.85 and 6.89 mm(2) respectively. These brackets were used combined with a sandblasting treatment with two different types of abrasive particles, alumina (Al(2)O(3)) and silicon carbide (SiC) and applied to natural teeth in vitro. The abrasive particles used are bio-compatible and usually used in achieving increased roughness for improved adherence in biomedical materials. Sandblasting was performed at 2 bars for 2 s; three particle sizes were used: 80, 200 and 600 µm. Non-blasted samples were used as control. Each of the pieces were cemented to natural teeth with a self-curing composite. Samples were stored in physiologic serum at 5°C temperature. Tensile tests were performed with a universal testing machine. Brackets treated with sandblasted particles were measured to have an increased adhesion as compared to the control sample. The highest bond strength was measured for samples sandblasted with alumina particles of 80 and 200 µm combined with micro-milled brackets. The recorded stresses did not exceed the tensile strength of tooth enamel.

External apical root resorption in maxillary root-filled incisors after orthodontic treatment: a split-mouth design study.

INTRODUCTION: The purpose of this study was to compare, in a split mouth design, the external apical root resorption (EARR) associated with orthodontic treatment in root-filled maxillary incisors and their contralateral teeth with vital pulps. METHODOLOGY: The study sample consisted of 38 patients (14 males and 24 females), who had one root-filled incisor before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken before and after orthodontic treatment were used to determine the root resortion and the proportion of external root resorption (PRR), defined as the ratio between the root resorption in the endodontically treated incisor and that in its contralateral incisor with a vital pulp. The student's t-test, chi-square test and logistic regression analysis were used to determine statistical significance. RESULTS: There was no statistically significant difference (p > 0.05) between EARR in vital teeth (1.1 ± 1.0 mm) and endodontically treated incisors (1.1 ± 0.8 mm). Twenty-six patients (68.4%) showed greater resorption of the endodontically treated incisor than its homolog vital tooth (p > 0.05). The mean and standard deviation of PPR were 1.0 ± 0.2. Multivariate logistic regression suggested that PRR does not correlate with any of the variables analyzed. CONCLUSIONS: There was no significant difference in the amount or severity of external root resorption during orthodontic movement between root-filled incisors and their contralateral teeth with vital pulps.