Boolean model of the gene regulatory network of Pseudomonas aeruginosa CCBH4851.

Introduction: Pseudomonas aeruginosa infections are one of the leading causes of death in immunocompromised patients with cystic fibrosis, diabetes, and lung diseases such as pneumonia and bronchiectasis. Furthermore, P. aeruginosa is one of the main multidrug-resistant bacteria responsible for nosocomial infections worldwide, including the multidrug-resistant CCBH4851 strain isolated in Brazil. Methods: One way to analyze their dynamic cellular behavior is through computational modeling of the gene regulatory network, which represents interactions between regulatory genes and their targets. For this purpose, Boolean models are important predictive tools to analyze these interactions. They are one of the most commonly used methods for studying complex dynamic behavior in biological systems. Results and discussion: Therefore, this research consists of building a Boolean model of the gene regulatory network of P. aeruginosa CCBH4851 using data from RNA-seq experiments. Next, the basins of attraction are estimated, as these regions and the transitions between them can help identify the attractors, representing long-term behavior in the Boolean model. The essential genes of the basins were associated with the phenotypes of the bacteria for two conditions: biofilm formation and polymyxin B treatment. Overall, the Boolean model and the analysis method proposed in this work can identify promising control actions and indicate potential therapeutic targets, which can help pinpoint new drugs and intervention strategies.

Global patterns of plumage color evolution in island-living passeriform birds.

Island environments have the potential to change evolutionary trajectories of morphological traits in species relative to their mainland counterparts due to habitat and resource differences, or by reductions in the intensity of social or sexual selection. Latitude, island size, and isolation may further influence trait evolution through biases in colonization rates. We used a global dataset of passerine plumage color as a model group to identify selective pressures driving morphological evolution of island animals using phylogenetically-controlled analyses. We calculated chromaticity values from red and blue scores extracted from images of the majority of Passeriformes and tested these against the factors hypothesized to influence color evolution. In contrast to predictions based on sexual and social selection theory, we found consistent changes in island female color (lower red and higher blue chromaticity), but no change in males. Instead, island size and distance from mainland and other islands influenced color in both sexes, reinforcing the importance of island physiognomy in shaping evolutionary processes. Interactions between ecological factors and latitude also consistently influenced color for both sexes, supporting a latitudinal gradient hypothesis. Finally, patterns of color evolution varied among families, indicating taxon-specific microevolutionary processes in driving color evolution. Our results show island residency influences color evolution differently between sexes, but the patterns in both sexes are tempered by ecological, island characteristics, and phylogenetic effects that further vary in their importance among families. The key role of environmental factors in shaping bird plumage on islands further suggests a reduced importance of sexual and social factors in driving color evolution.

Evaluation of the labial protrusion and lip esthetic changes after complete denture treatment through stereophotogrammetry.

PURPOSE: Evaluating the facial esthetics of complete denture (CD) treatment using a 3D analysis of the lower third of the face before (T1) and after (T2) treatment by comparing and correlating measurements. MATERIAL AND METHODS: Thirty-one edentulous patients were enrolled, and three-dimensional (3D) images were captured before (T1) and after (T2) CD delivery. Twelve landmarks were established in the face. Linear, angular, surface, and perimeter measurements were evaluated and compared with the paired t test. The delta (Δ) values (T2-T1) were assessed by the Spearman correlation to verify the associations between all measurements according to the facial parameters (α=.05). RESULTS: Statistical differences were identified in the lower third of the face in the linear measurement Sn-Gn (P = 0.006), the angular measure Tright-Pg-Tleft (P = 0.004), and at the surface of the lower third of the face (P = 0.001). All measurements were statistically different in the labial protrusion area: the nasolabial angle (Prn-Sn-Ls), the surface, and the perimeter (P = 0.001). In the lip evaluation, statistical differences were observed in the linear (Ls-Li), surface, and perimeter measurements (P = 0.001). CONCLUSION: The facial esthetic proportions of the linear and perimeter measurements increased, and the angles of sealed lips and nasolabial and lower facial convexity decreased after CD delivery. The present study showed a clinical important correlation between linear and angular measurements that should help restore facial esthetics, providing metrics that can aid the clinician in facial composition.

An updated gene regulatory network reconstruction of multidrug-resistant Pseudomonas aeruginosa CCBH4851.

BACKGROUND: Healthcare-associated infections due to multidrug-resistant (MDR) bacteria such as Pseudomonas aeruginosa are significant public health issues worldwide. A system biology approach can help understand bacterial behaviour and provide novel ways to identify potential therapeutic targets and develop new drugs. Gene regulatory networks (GRN) are examples of in silico representation of interaction between regulatory genes and their targets. OBJECTIVES: In this work, we update the MDR P. aeruginosa CCBH4851 GRN reconstruction and analyse and discuss its structural properties. METHODS: We based this study on the gene orthology inference methodology using the reciprocal best hit method. The P. aeruginosa CCBH4851 genome and GRN, published in 2019, and the P. aeruginosa PAO1 GRN, published in 2020, were used for this update reconstruction process. FINDINGS: Our result is a GRN with a greater number of regulatory genes, target genes, and interactions compared to the previous networks, and its structural properties are consistent with the complexity of biological networks and the biological features of P. aeruginosa. MAIN CONCLUSIONS: Here, we present the largest and most complete version of P. aeruginosa GRN published to this date, to the best of our knowledge.

Disruption of cellular iron homeostasis by IREB2 missense variants causes severe neurodevelopmental delay, dystonia and seizures.

Altered brain iron homeostasis can contribute to neurodegeneration by interfering with the delivery of the iron needed to support key cellular processes, including mitochondrial respiration, synthesis of myelin and essential neurotransmitters. Intracellular iron homeostasis in mammals is maintained by two homologous ubiquitously expressed iron-responsive element-binding proteins (IRP1 and IRP2). Using exome sequencing, two patients with severe neurodegenerative disease and bi-allelic mutations in the gene IREB2 were first identified and clinically characterized in 2019. Here, we report the case of a 7-year-old male patient with compound heterozygous missense variants in IREB2, whose neurological features resembled those of the two previously reported IRP2-deficient patients, including a profound global neurodevelopmental delay and dystonia. Biochemical characterization of a lymphoblast cell line derived from the patient revealed functional iron deficiency, altered post-transcriptional regulation of iron metabolism genes and mitochondrial dysfunction. The iron metabolism abnormalities of the patient cell line were reversed by lentiviral-mediated restoration of IREB2 expression. These results, in addition to confirming the essential role of IRP2 in the regulation of iron metabolism in humans, expand the scope of the known IRP2-related neurodegenerative disorders and underscore that IREB2 pathological variants may impact the iron-responsive element-binding activity of IRP2 with varying degrees of severity. The three severely affected patients identified so far all suffered from complete loss of function of IRP2, raising the possibility that individuals with significant but incomplete loss of IRP2 function may develop less severe forms of the disease, analogous to other human conditions that present with a wide range of phenotypic manifestations.

Evaluation of cheiloplasty and palatoplasty on palate surface area in children with oral clefts: longitudinal study.

This study evaluated the palatal surface area in children with different oral clefts after primary surgeries and at five years of age. This longitudinal study was composed by 216 digital models: unilateral complete cleft lip (UCL), unilateral complete cleft lip and palate (UCLP), and complete cleft palate (CP). The models were analysed at four time periods: T1 (before cheiloplasty), T2 (before palatoplasty), T3 (after palatoplasty); and T4 - (at five years of age). Area of the dental arches was measured through stereophotogrammetry software. Measurements evaluated with Student's test and ANOVA followed by the Tukey test (p<0.05) (AQ 1). In the UCL group, the palatal surface area significantly increased among phases. In the primary surgery periods, UCLP and CP significantly decreased (p<0.001). Palatal area in the UCLP group was significantly greater than the CP group. Overall, no statistically significant differences occurred among groups. At T4, the area of the palate in the UCL group was significantly greater than the UCLP group and no significant differences occurred between UCLP and CP groups. This study suggests that cheiloplasty did not inhibit the growth of the palatal surface area in children with UCL and UCLP. Palatoplasty significantly decreased the palatal area in children with UCLP and CP, demonstrating a significant negative effect of palatal repair on maxillary growth. At five years, children with UCLP and CP had a significantly smaller palate area than those with UCL.

3D morphometric evaluation of the dental arches in children with cleft lip and palate submitted to different surgical techniques.

OBJECTIVES: This study aimed to compare dimensional alterations of dental arches in children with unilateral complete cleft lip and palate before and after different techniques of primary plastic surgeries. MATERIALS AND METHODS: The sample was divided into two groups: group 1-cheiloplasty by Millard's technique and one-stage palatoplasty by von Langenbeck's technique; group 2-cheiloplasty by Millard's technique and two-stage palatoplasty: anterior palatoplasty by Hans Pichler's technique and posterior palatoplasty by Sommerlad's technique. Dental arches were evaluated before (T1), after the first phase (T2), and 1 year after the second phase (T3) of primary surgeries. Linear measurements and palatal area were assessed. To analyze the method's error, interclass correlation coefficient was applied. ANOVA (followed by Tukey test), dependent, and independent t-test were used (p < 0.05). RESULTS: At T1, the intertuberosity distance was statistically greater in G2 (p = 0.004). At T2, the anterior length of the dental arch was statistically greater in G2 (p = 0.025), while the area of the smaller palatal segment (p = 0.001), cleft area (p = 0.014), and total area (p = 0.002) were statistically smaller in G2. At T3, the intertuberosity distance was statistically greater in G2 (p = 0.017). CONCLUSION: This study suggests that cheiloplasty and one-stage palatoplasty resulted in smaller growth of maxilla than cheiloplasty and two-stage palatoplasty in the linear measurements (T-T' and I-CC') and total area of the dental arches. CLINICAL RELEVANCE: Surgical protocols need to be evaluated to verify their effects aiming at improving the clinical practice of the interdisciplinary team, determining new parameters for the rehabilitation of individuals with cleft lip and palate.

An updated gene regulatory network reconstruction of multidrug-resistant Pseudomonas aeruginosa CCBH4851

BACKGROUND Healthcare-associated infections due to multidrug-resistant (MDR) bacteria such as Pseudomonas aeruginosa are significant public health issues worldwide. A system biology approach can help understand bacterial behaviour and provide novel ways to identify potential therapeutic targets and develop new drugs. Gene regulatory networks (GRN) are examples of in silico representation of interaction between regulatory genes and their targets. OBJECTIVES In this work, we update the MDR P. aeruginosa CCBH4851 GRN reconstruction and analyse and discuss its structural properties. METHODS We based this study on the gene orthology inference methodology using the reciprocal best hit method. The P. aeruginosa CCBH4851 genome and GRN, published in 2019, and the P. aeruginosa PAO1 GRN, published in 2020, were used for this update reconstruction process. FINDINGS Our result is a GRN with a greater number of regulatory genes, target genes, and interactions compared to the previous networks, and its structural properties are consistent with the complexity of biological networks and the biological features of P. aeruginosa. MAIN CONCLUSIONS Here, we present the largest and most complete version of P. aeruginosa GRN published to this date, to the best of our knowledge.

A Systematic Strategy to Find Potential Therapeutic Targets for Pseudomonas aeruginosa Using Integrated Computational Models.

Pseudomonas aeruginosa is an opportunistic human pathogen that has been a constant global health problem due to its ability to cause infection at different body sites and its resistance to a broad spectrum of clinically available antibiotics. The World Health Organization classified multidrug-resistant Pseudomonas aeruginosa among the top-ranked organisms that require urgent research and development of effective therapeutic options. Several approaches have been taken to achieve these goals, but they all depend on discovering potential drug targets. The large amount of data obtained from sequencing technologies has been used to create computational models of organisms, which provide a powerful tool for better understanding their biological behavior. In the present work, we applied a method to integrate transcriptome data with genome-scale metabolic networks of Pseudomonas aeruginosa. We submitted both metabolic and integrated models to dynamic simulations and compared their performance with published in vitro growth curves. In addition, we used these models to identify potential therapeutic targets and compared the results to analyze the assumption that computational models enriched with biological measurements can provide more selective and (or) specific predictions. Our results demonstrate that dynamic simulations from integrated models result in more accurate growth curves and flux distribution more coherent with biological observations. Moreover, identifying drug targets from integrated models is more selective as the predicted genes were a subset of those found in the metabolic models. Our analysis resulted in the identification of 26 non-host homologous targets. Among them, we highlighted five top-ranked genes based on lesser conservation with the human microbiome. Overall, some of the genes identified in this work have already been proposed by different approaches and (or) are already investigated as targets to antimicrobial compounds, reinforcing the benefit of using integrated models as a starting point to selecting biologically relevant therapeutic targets.

The COVID-19 pandemic as an opportunity to weaken environmental protection in Brazil.

This paper examines the effects of the COVID-19 pandemic on environmental protection and legislation in Brazil. We evaluate major legislative actions, environmental fines and deforestation since January 2019. We show that 57 legislative acts aimed at weakening environmental protection in Brazil during the current administration, almost half of which in the seven-month period of the pandemic in Brazil, with September 2020 as the month with the most legislative acts (n = 16). These acts either deregulated or weakened current environmental legislation, with a number of them aimed at dismantling the main federal institutions in charge of environmental protection. We also found a 72% reduction in environmental fines during the pandemic, despite an increase in Amazonian deforestation during this period. We conclude that the current administration is taking advantage of the COVID-19 pandemic to intensify a pattern of weakening environmental protection in Brazil. This has the potential to intensify ongoing loss of biodiversity, greenhouse gas emissions, and the likelihood of other zoonotic disease outbreaks, and inflict substantial harm to traditional and indigenous peoples. We highlight the key role of the scientific community, media and civil society, national and international levels, in order to reverse these harmful actions.

Prospective cohort 3D study of dental arches in children with bilateral orofacial cleft: Assessment of volume and superimposition.

BACKGROUND: Cohort studies have evaluated dental arches of children. AIM: To evaluate the volumetric, linear, palatal surface area, and the dental arch superimposition of participants with bilateral complete cleft lip (BCL) and bilateral cleft lip and palate (BCLP) surgically treated in a specialized hospital. DESIGN: One hundred and thirty six digitized dental models evaluated before cheiloplasty (T1), after cheiloplasty (T2), and after palatoplasty (T3). The stereophotogrammetry software analysed the volume, palate superimposition, linear, and area measurements. RESULTS: In BCL group, at T2, C-C', T-T', area, and volume significantly increased (P = .000, P < .000, P = .010 e P = .003, respectively). In BCLP group, the comparison T3 × T1 showed that C-C' decreased, whereas T-T' and the area increased (P < .000, P < .000, P = .000). The volume increased at T2, but decreased at T3 (P < .000) in participants with BCLP. The intergroup analysis revealed that C-C', T-T', I-C', and I-C were significantly smaller in participants with BCLP (P < .000, P = .016, P = .001 e P = .020, respectively), whereas the volume, superimposition, and area were statistically similar between groups (P > .05). CONCLUSION: The comparison between bilateral orofacial clefts showed reduction in the transversal and anteroposterior linear measurements, but not in the area and volume, which was confirmed by the superimposition of the dental arches.

Evolution of altitudinal migration in passerines is linked to diet.

Bird migration is typically associated with a latitudinal movement from north to south and vice versa. However, many bird species migrate seasonally with an upslope or downslope movement in a process termed altitudinal migration. Globally, 830 of the 6,579 Passeriformes species are considered altitudinal migrants and this pattern has emerged multiple times across 77 families of this order. Recent work has indicated an association between altitudinal migration and diet, but none have looked at diet as a potential evolutionary driver. Here, we investigated potential evolutionary drivers of altitudinal migration in passerines around the world by using phylogenetic comparative methods. We tested for evolutionary associations between altitudinal migration and foraging guild and primary habitat preference in passerines species worldwide. Our results indicate that foraging guild is evolutionarily associated with altitudinal migration, but this relationship varies across zoogeographical regions. In the Nearctic, herbivorous and omnivorous species are associated with altitudinal migration, while only omnivorous species are associated with altitudinal migration in the Palearctic. Habitat was not strongly linked to the evolution of altitudinal migration. While our results point to diet as a potentially important driver of altitudinal migration, the evolution of this behavior is complex and certainly driven by multiple factors. Altitudinal migration varies in its use (for breeding or molting), within a species, population, and even at the individual level. As such, the evolution of altitudinal migration is likely driven by an ensemble of factors, but this study provides a beginning framework for understanding the evolution of this complex behavior.

Analysis of Dental Arch in Children With Oral Cleft Before and After the Primary Surgeries.

This study aimed to evaluate longitudinally the alteration of the dental arch dimensions of children with different oral cleft types, before and after the primary surgeries. Three-dimensional images of the maxillary dental casts of children with unilateral complete cleft lip (G1), unilateral complete cleft lip and palate (G2), and cleft palate (G3). The children were evaluated at pre-cheiloplasty (T1), pre-palatoplasty (T2), and 1 year after palatoplasty (T3). The measurements obtained: intercanine (C-C') and intertuberosity (T-T') distances, anterior (I-CC') and total (I-TT') arch lengths. To analyze the intraexaminer error, paired t-test was applied and Dahlbergh formula. The intragroups comparisons were applied: paired t-test, ANOVA followed by Tukey, Wilcoxon test, and Kruskal-Wallis test followed by Dunn test. The intergroup comparisons were performed by independent t-test and Mann-Whitney test. In G1, the C-C', T-T', and the I-TT' distances revealed a significant increase of the maxilla. In G2, the C-C' distance statistically decreased from T1 to T3, T-T' distance showed statistical increase from T1 to T3. The I-TT' length increased with statistically significant differences between T1 and T3, T2 and T3. In G3, the C-C', T-T', and I-TT' distance increased was statistically significant. The longitudinal evaluation of the changes occurred in the dental arches with different oral cleft types showed that cheiloplasty and palatoplasty caused the most alterations in the development of the maxillary dimensions of children with complete cleft lip and palate.

Longitudinal morphometric analysis of dental arch of children with cleft lip and palate: 3D stereophotogrammetry study.

OBJECTIVE: This study aimed to perform a longitudinal morphometric analysis of the alterations of the maxillary dental arches in children with cleft lip and palate before and after primary lip and/or palate surgeries using a 3-dimensional stereophotogrammetry system. STUDY DESIGN: The sample consisted of dental casts of 60 children with complete unilateral cleft lip (UCL) and complete unilateral cleft lip and palate (UCLP). Dental arches were evaluated before cheiloplasty (T1), after cheiloplasty (T2), and 1 year after palatoplasty (T3). Independent t test and Mann-Whitney U test were used for intergroup comparisons, and paired t test, Wilcoxon's test, and repeated-measures analysis of variance (ANOVA), followed by Tukey's test, were used for intragroup comparisons. RESULTS: At T1, the intercanine and intertuberosity distances in the UCLP group were statistically greater than those in the UCL group. At T2, the maxillary dimensions significantly increased, except for the intertuberosity distance in UCL. Between T1 and T3, the intercanine distance and the anterior length decreased significantly, whereas the intertuberosity distance and the total length of the palate increased significantly. CONCLUSIONS: Our results indicated that the primary lip surgery altered the development of dental arches, evidently in children with UCLP. The primary palate surgery interfered in the growth of the anterior palatal region in the UCLP group. Children with UCLP had more restricted development of the maxillary dental arch compared with children with UCL.

Post-surgical effects on the maxillary segments of children with oral clefts: New three-dimensional anthropometric analysis.

This study aimed to use new three-dimensional (3D) anthropometric analyses to verify the post-surgical effects on the maxillary segments of children with unilateral cleft lip and palate. The sample was composed by digitized dental models of 60 children with unilateral complete cleft lip and alveolus (UCLA) and complete unilateral cleft lip and palate (UCLP). The impressions were taken before cheiloplasty (T1), after cheiloplasty (T2), and after palatoplasty (T3). The 3D anthropometric analyses of digitized dental casts were obtained through a specific software. Intragroup changes were applied paired t test and Wilcoxon test (UCLA group) and for the UCLP group, repeated-measures analyses of variance followed by the Tukey test. For intergroup analyses, an independent t test and Mann-Whitney test were used. The palatal dimensional changes of UCLA group showed that the distances IC, I-T', and I-T significantly increased after cheiloplasty (p = 0.0002, p = 0.0007 and p < 0.0001, respectively). In the UCLP group, the IC' distance statistically decreased in the post-surgical periods (p < 0.0001), while the I-T distance increased (p < 0.0001). The IC distance increased after cheiloplasty (p < 0.0001). The I-T' distance increased between T2 and T3 with statistically significant differences (p = 0.0037). The intergroup analysis of palatal development (T2-T1) showed that the distances IC' and I-T' demonstrated a reduction of the dental arches growth of UCLP group compared with the UCLA group, with statistically significant differences. The new 3D anthropometric analysis showed that the development of the maxillary segments changed after surgical repair. The UCLP group demonstrated a reduction of the dental arches growth compared with the UCLA group.

The semiology of benign focal epilepsy with affective symptoms.

Benign focal epilepsy with affective symptoms (BFEAS) is a rare childhood epilepsy syndrome essentially characterized by "epileptic attacks with affective symptoms of a terrifying type". Since the original description, approximately 50 cases have been reported. To our knowledge, however, none of the studies included video-EEG data. Herein, we detail the electroclinical features of a neurodevelopmentally normal 9-year-old boy with epilepsy since the age of 2 years. His seizure semiology essentially consisted of nocturnal focal seizures featuring abrupt fear and autonomic phenomena (such as excessive sweating, repeated swallowing, and coughing), associated with impaired consciousness. These seizures were often secondary generalized, and he had multiple episodes of convulsive status epilepticus. He has been seizure-free for the past year and a half on dual antiepileptic therapy with sulthiamine and valproate. His intellectual and social abilities are excellent (IQ of 116), although he does have difficulties particularly in language learning, and was recently diagnosed with phonological dyslexia with dysorthography. By presenting our patient's history and video-EEG, we intend to further detail the semiology of seizures with affective symptomatology. [Published with video sequence on www.epilepticdisorders.com].

Research conference summary from the 2014 International Task Force on ATP1A3-Related Disorders.

OBJECTIVE: ATP1A3-related neurologic disorders encompass a broad range of phenotypes that extend well beyond initial phenotypic criteria associated with alternating hemiplegia of childhood (AHC) and rapid-onset dystonia parkinsonism. METHODS: In 2014, the Alternating Hemiplegia of Childhood Foundation hosted a multidisciplinary workshop intended to address fundamental challenges surrounding the diagnosis and management of individuals with ATP1A3-related disorders. RESULTS: Workshop attendees were charged with the following: (1) to achieve consensus on expanded diagnostic criteria to facilitate the identification of additional patients, intended to supplement existing syndrome-specific diagnostic paradigms; (2) to standardize definitions for the broad range of paroxysmal manifestations associated with AHC to disseminate to families; (3) to create clinical recommendations for common recurrent issues facing families and medical care providers; (4) to review data related to the death of individuals in the Alternating Hemiplegia of Childhood Foundation database to guide future efforts in identifying at-risk subjects and potential preventative measures; and (5) to identify critical gaps where we most need to focus national and international research efforts. CONCLUSIONS: This report summarizes recommendations of the workshop committee, highlighting the key phenotypic features to facilitate the diagnosis of possible ATP1A3 mutations, providing recommendations for genetic testing, and outlining initial acute management for common recurrent clinical conditions, including epilepsy.

Focal Seizures in Patients With SCN1A Mutations.

The SCN1A gene has been implicated in the etiology of various forms of epilepsy. New research has linked this gene to specific types of epilepsy, all of which present in infancy or early childhood. This study examines the time course and pathology of pediatric patients who have a mutation in the SCN1A gene in order to open a discussion regarding the key trends of this form of epilepsy as well as important clinical considerations in management for patients who present with symptoms relating to the SCN1A mutations. We retrospectively examined 20 patients who presented to the clinic with focal seizures, as well as were positive for an SCN1A genetic mutation. Despite the small sample size, we were able to find important trends in the time course of the disorder as well as important areas of clinical practice that must be taken into consideration for these patients.

Effect of whitening dentifrices on the surface roughness of a nanohybrid composite resin.

OBJECTIVES: The present study verified the influence of whitening dentifrices on the surface roughness of a nanohybrid composite resin. MATERIALS AND METHODS: Thirty-two specimens were prepared with Filtek™ Z350 XT (3M/ESPE) and randomly divided into four groups (n = 08) that were subjected to brushing simulation equivalent to the period of 1 month. The groups assessed were a control group with distilled water (G1), Colgate Total 12 Professional Clean (G2), Sensodyne Extra Whitener Extra Fresh (G3), and Colgate Luminous White (G4). A sequence of 90 cycles was performed for all the samples. The initial roughness of each group was analyzed by the Surface Roughness Tester (TR 200-TIME Group Inc., CA, USA). After the brushing period, the final roughness was measured, and the results were statistically analyzed using nonparametric Kruskal-Wallis and Dunn tests for intergroup roughness comparison in the time factor. For intragroup and "Δ Final - Initial" comparisons, the Wilcoxon test and (one-way) ANOVA were, respectively, performed (α = 0.05). RESULTS: The roughness mean values before and after brushing showed no statistically significant difference when the different dentifrices were used. None of the dentifrices analyzed increased significantly the nanohybrid composite resin surface roughness in a 1 month of tooth brushing simulation. CONCLUSIONS: These results suggest that no hazardous effect on the roughness of nanohybrid composite resin can be expected when whitening dentifrices are used for a short period. Similar studies should be conducted to analyze other esthetic composite materials.