Effect of power arm length combined with additional anterior torque on the axial orientation of the maxillary incisors during en-masse retraction: A finite element analysis.

INTRODUCTION: This study aimed to clarify the effect of power arm length combined with additional torque incorporated into the archwire on the controlled movement of the anterior teeth using the finite element method. METHODS: An adult patient requiring medium anchorage after extraction of the maxillary first premolars was selected for this study. The power arms were placed between the lateral incisor and the canine at 3 levels: 3 mm, 6 mm, and 9 mm. A 150 g of retraction force was applied from each height of the anterior hook to the first molar tube, with 0°, 5°, and 10° of applied lingual root torque on the incisors. RESULTS: A 3-mm hook with 10° of applied torque, a 6-mm hook with 5° of applied torque, or a 9-mm hook with no extra torque constituted the best combinations targeted at controlling the inclination of incisors during retraction. Extrusion and distal tipping of the canine were observed. Moreover, mesial tipping and mesiopalatal rotation of the molar were unavoidable. Finally, intercanine and intermolar widths were decreased. CONCLUSIONS: Adding extra torque on the incisors or using high torque brackets is recommended for patients with maxillary first premolar extraction.

Three-dimensional comparison of continuous and segmented arch techniques in the traction of palatally impacted canines using a non-linear finite element analysis.

OBJECTIVE: To compare the three-dimensional (3D) effects of canine traction on the maxillary teeth when using two different traction methods, the continuous and the segmented arch wire techniques; then to test whether adding a transpalatal arch (TPA) would affect their response to traction. DESIGN: Finite element analysis. METHODS: A cone-beam computed tomography (CBCT) scan of a patient with bilateral palatally impacted canines was chosen, from which a 3D model was derived and imported into ABAQUS. Two arch wires were modelled, a continuous round one and a segmented rectangular one. Four models were obtained by adding a TPA to both techniques. A 100° imposed rotation was then applied at the intersection between the vertical loop and the horizontal segment of each wire. Initial displacement of the maxillary tooth in the labio-lingual and in the vertical directions was measured. The absolute maximum principal stress of the periodontal ligament (PDL) was also assessed. RESULTS: Traction using a continuous arch wire led to different movement patterns of all teeth, some of them were tipped in a labial direction while others were lingually tipped. Traction using a segmented arch wire resulted in a retroclination of the posterior teeth and a proclination of the anterior teeth with a high level of stress on the premolars' PDL. Adding the TPA only affected the displacement of the first molars. The right side showed a maximum displacement of the first premolar, while the left side showed it on the lateral. The total displacement on the right side was higher than the left side. CONCLUSION: The segmented technique caused a uniform displacement of all teeth while the continuous one showed a non-uniform displacement. The angulation and position of the vertical loop affected the displacement of the maxillary teeth. The addition of a TPA acted only on the first molars.

Poor visuo-spatial orientation and path memorization in children with dyslexia.

PURPOSE: Given the importance of spatial representation and navigation in the natural environment and the presence of sensory motor integration impairment in dyslexic children the aim of this study was to explore the capability in spatial orientation task in dyslexic children. MATERIALS AND METHODS: We included forty children: 26 dyslexic children (mean age: 10.1 ± 0.3 years old) and 14 typically developing (TD) children (mean age: 10.1 ± 0.4 years old). Children have to walk on an unguided isosceles rectangle triangle of 3 meters that was marked on the ground of a room, during two visual conditions: eyes open and eyes closed. Their paths were recorded using the HTC Vive system (Base + Trackers) with a refresh rate of 90 Hz with accuracy < 0.05 mm. RESULTS: Results underlined that both groups of children reported poor performance during eyes closed condition. Moreover, dyslexic children, reported poor spatial orientation capabilities in the most difficult conditions, that is during reproduction of hypotenuse and angle of 45 deg. CONCLUSIONS: We suggested that visual information is important during walking; the poor body orientation observed in dyslexic children could be due to a deficient integration of the sensorial inputs (visual, vestibular and proprioceptive). Further studies testing vestibular/cerebellar rehabilitation could be useful for these kinds of children.HighlightsChildren with dyslexia showed poor spatial orientation capabilities compared to typically developing children, particularly when visual inputs are not available and in the most difficult conditions (like rotation of the body).Poor motor abilities reported by children with dyslexia could be due to cerebrocerebellar pathways impairments.

Three-dimensional comparison of the effects of sliding mechanics in labial and lingual orthodontics using the finite element method.

INTRODUCTION: The extraction of maxillary first premolars is usually the treatment of choice to resolve crowding, alveolar protrusion, or Class II malocclusion. The demand for a lingual orthodontic treatment is increasing because of its esthetic value; therefore, understanding lingual biomechanics is essential to every clinician. This study compared the 3-dimensional (3D) effects of sliding mechanics in labial and lingual orthodontics using the finite element method. METHODS: Twelve 3D finite element models were created with different power arm heights and miniscrew positions. A 150 g of retraction force was applied from the head of the miniscrew to the power arm. The 3D displacement of the original nodes was measured, and the stress distribution on defined element zones of the periodontal ligament. RESULTS: Different force directions led to different movement patterns and stress distribution. The lingual models showed a more important lingual crown tipping, extrusion, and higher stress values than the labial models. Results were not affected by the vertical position of the miniscrew. CONCLUSIONS: Bodily en-masse retraction was not achieved in all models. Adding extra torque to the archwires is essential to prevent excessive lingual crown tipping. The lingual appliance induced more lingual tipping and extrusion of the anterior teeth. Expanding the archwire is important to minimize the risk of intercanine width reduction. The vertical position of the miniscrew does not affect the results of en-masse retraction.

The Microbiome of the Lebanese Wild Apple, Malus trilobata, is a Rich Source of Potential Biocontrol Agents for Fungal Post-harvest Pathogens of Apples.

The widespread use of harmful fungicides in the agricultural sector has led to a demand for safer alternatives to protect against crop pathogens. The domestic apple is the second most highly consumed fruit in the world and encounters several pre- and post-harvest fungal and bacterial phytopathogens. The goal of this study was to explore the uncharacterized microbiome of a wild apple, Malus trilobata, as a potential source of novel biocontrol agents for two post-harvest fungi that affect commercial apples: Botrytis cinerea and Penicillium expansum. We sampled microflora associated with the leaves, bulk soil, and roots of Malus trilobata in two regions of Lebanon: Ehden reserve in the north and Dhour EL Choueir near Beirut. The two regions have different soil types Dhour EL Choueir and samples from the two regions showed very different microbial compositions, with greater microbial diversity among those from Ehden reserve. Molecular characterization revealed a wide variety of genera displaying activity against the two fungal pathogens, including several with previously unknown antifungal activity: Bosea, Microlunatus, Microbacterium, Mycetecola, Rhizobium and Paraphoma. In total, 92 strains inhibited Penicillium expansum (39%) and 87 strains inhibited Botrytis cinerea (38%) out of 237 screened. Further chemical and genetic characterization of one or more selected strains could pave the way for future development of new biocontrol agents for post-harvest applications.

Impact of preoperative fractional flow reserve on arterial bypass graft anastomotic function: the IMPAG trial.

AIMS: Visual estimation is the most commonly used method to evaluate the degree of coronary artery stenosis prior to coronary artery bypass grafting. In interventional cardiology, the use of fractional flow reserve (FFR) to guide revascularization decisions has become routine. We investigated whether the preoperative FFR measurement of coronary lesions is associated with anastomosis function 6 months after surgical revascularization using a multiarterial grafting strategy. METHODS AND RESULTS: In this prospective double-blind study, 67 patients were enrolled from two institutions in Europe and Canada. From these patients, 199 coronary lesions were assessed visually and with FFR at the time of the preoperative angiogram. All patients received coronary revascularization using multiple arterial grafts. A post-operative 6-month angiogram was performed to assess anastomosis functionality using a described angiographic method. The primary outcome was the association between preoperative FFR values and anastomosis function 6 months after surgery. Preoperative FFR was significantly associated with 6-months anastomotic function for all conduits and for all targets (P < 0.001). An FFR value of ≤0.78 was associated with an anastomotic occlusion rate of 3%. CONCLUSION: We found a significant association between the preoperative FFR measurement of the target vessel and the anastomotic functionality at 6 months, with a cut-off of 0.78. Integration of FFR measurement into the preoperative diagnostic workup before multiarterial coronary surgical revascularization leads to improved anastomotic graft function. CLINICAL TRIALS. GOV IDENTIFIER: NCT02527044.

Changes of arch form at the end of orthodontic treatment, based on the Ricketts pentamorphic arch forms.

INTRODUCTION: Maintenance of the intercanine and intermolar distances reduces the risk of relapse and increases the chance of stability; these values represent the limits of the arch, resulting from the muscular balance of each patient. The ideal would be to reproduce the patient's arch form individually. The Ricketts pentamorphic arch forms allow the clinician to choose among 5 shapes, the one that best fits the patient's arch form. The objective of this study was to evaluate the effect of orthodontic treatment without extraction according to the pentamorphic arch forms on mandibular arches of different forms. METHODS: Fifty patients were included in the study. For each patient, the pretreatment and end-of-treatment models were scanned by 3Shape Trios (3Shape, Copenhagen, Denmark) and transferred to the OrthoAnalyzer software (3Shape) version 2017-11.7.1.3 for measurements and superimpositions. The following measurements were made on the mandibular arches for both initial and final digital models: arch depth; intercanine distance, the distance between the first premolars, the distance between the second premolars, the distance between the first molars, and the distance between the second molars. Three superimpositions were made: superimposition between the initial arch and the corresponding form of the pentamorphic arch forms, superimposition between the final arch and the corresponding form of the pentamorphic arch forms, and superimposition between the initial arch and the final arch. The largest difference between the superimposed arches in each region was measured. RESULTS: This study showed that intercanine distance (P = 0.236), the distance between the first premolars (P = 0.074), and the distance between the first molars (P = 0.616) did not significantly change after orthodontic treatment. In contrast, the distance between the second molars (P = 0.028) and the arch depth (P <0.001) increased significantly after orthodontic treatment. The mean of the largest difference in the absolute value of all the superimpositions is significantly different from the theoretical value 0 (P <0.001), but clinically, this difference is significant only in certain premolars and molars regions. CONCLUSIONS: This study has shown that the pentamorphic arch forms maintained the arch shape in the sagittal and transverse directions, except for an expansion of the distance between the mandibular second molars.

Evaluation of the ideal position of the maxillary incisor relative to upper lip thickness.

INTRODUCTION: The anteroposterior position of the maxillary incisors has been studied since the beginning of cephalometric research. Most reports of ideal position have been based on measurements made on subjects with Class I occlusion without consideration of other facial variables. However, the ideal position is reflected in the soft tissues by the position of the lips. The purpose of this study was to consider the position of the maxillary incisor relative to other factors, including the thickness of the upper lip, and to evaluate its most aesthetic position using profile photographs. METHODS: The subjects in this study were 130 patients with Class I occlusion; their sex, age, thickness of the upper lip, and angular position of the maxillary incisor were recorded. From these 130 patients, 70 profile photographs that met the inclusion criteria were chosen for further evaluation. A survey was conducted among 60 lay people, 60 dentists, and 60 orthodontists. They were asked to classify the sets of photographs, from the most esthetic position of the upper lip to the least esthetic. RESULTS: For patients with thin lips, raters tended to prefer a more protruded position of the incisor than normal or between 8.0 mm and 11.5 mm in front of the Na-B bone and 4 mm in front of the Na-A bone. For patients with thick lips, the position of the incisor did not affect the perception of the profile. CONCLUSIONS: A correct skeletal scheme or Class I occlusion does not necessarily result in ideal facial harmony. Therefore, it will be necessary to consider all the factors that come into play, especially the lips, which are a key element in facial esthetics.

Estimation and Comparison of the Duration of the Pubertal Peak in Skeletal Class II and Class I Subjects Using the Cervical Vertebrae Maturation Index Method.

AIM: The purpose of this study is to estimate and compare the duration of the pubertal peak in skeletal class II and class I subjects and to detect any difference between boys and girls or between hypo-, normo-, and hyperdivergent subjects for skeletal maturation indicator (CVM) in white Caucasians. MATERIALS AND METHODS: 346 subjects were selected from 3,119 examined files. Pretreatment lateral cephalometric records were hand-traced and divided following the anteroposterior skeletal relationship, the gender, the vertical pattern, and the skeletal maturation. The duration of the pubertal peak was calculated based on the chronological age interval according to each group. The age of onset of the active growth and the duration of the pubertal peak were compared between the different groups studied. RESULTS: Pubertal peak had a mean duration of 13 months in skeletal class I subjects, 19 months in skeletal class II subjects, 15 months in girls, 20 months in boys, 13 months in normodivergent and hypodivergent subjects, whereas in hyperdivergent subjects, it lasted 18 months. CONCLUSION: The growth interval corresponding to the pubertal growth spurt (CS3-CS4) was (1) significant between skeletal class I and class II subjects, (2) longer in boys, and (3) longer in hyperdivergent subjects. CLINICAL SIGNIFICANCE: Orthodontic treatments can start earlier for girls in class I or class II relationship and for hyperdivergent subjects as well. Furthermore, boys and subjects in class II skeletal relationship have a significantly longer duration of the pubertal peak and consequently a much efficient orthopedic and orthodontic treatment.

A mutation update on the LDS-associated genes TGFB2/3 and SMAD2/3.

The Loeys-Dietz syndrome (LDS) is a connective tissue disorder affecting the cardiovascular, skeletal, and ocular system. Most typically, LDS patients present with aortic aneurysms and arterial tortuosity, hypertelorism, and bifid/broad uvula or cleft palate. Initially, mutations in transforming growth factor-ß (TGF-ß) receptors (TGFBR1 and TGFBR2) were described to cause LDS, hereby leading to impaired TGF-ß signaling. More recently, TGF-ß ligands, TGFB2 and TGFB3, as well as intracellular downstream effectors of the TGF-ß pathway, SMAD2 and SMAD3, were shown to be involved in LDS. This emphasizes the role of disturbed TGF-ß signaling in LDS pathogenesis. Since most literature so far has focused on TGFBR1/2, we provide a comprehensive review on the known and some novel TGFB2/3 and SMAD2/3 mutations. For TGFB2 and SMAD3, the clinical manifestations, both of the patients previously described in the literature and our newly reported patients, are summarized in detail. This clearly indicates that LDS concerns a disorder with a broad phenotypical spectrum that is still emerging as more patients will be identified. All mutations described here are present in the corresponding Leiden Open Variant Database.

Effect of Intraoral Aging on Debris Accumulation and Friction of First Molar Tubes.

AIM: The aim of this article was to evaluate the impact of intraoral aging and site specificity on debris accumulation and friction in molar tubes after intraoral use. MATERIALS AND METHODS: A total of 80 intraorally used first molar convertible tubes were provided by 20 orthodontic adolescent patients after 6 months of treatment. The specimens were divided into eight groups (n = 10) according to the mouth quadrant and the type of examination [four groups of ten tubes for scanning electron microscope (SEM) and four groups of ten tubes for friction test]. Scanning electron microscope examination was performed after opening the convertible caps and friction test was executed using a 0.019'' × 0.025'' stainless steel wire, which was inserted in the tubes belonging to each group. The Mann-Whitney test, analysis of variance (ANOVA), and Bonferroni tests were performed for statistical analysis at 0.01 level of significance. RESULTS: There was a significant increase in the amount of debris and frictional force after 6 months of intraoral exposure (p < 0.0001). Debris scores were higher (10% increase) on the upper tubes when compared with the lower ones, with no statistical difference. Mean frictional force ranged from 0.22 to 0.26 N according to the mouth quadrant, but the difference between groups was also not significant. CONCLUSION: After 6 months of intraoral exposure, there was a significant increase in the amount of debris in the first molar tube slots, leading to significantly higher frictional forces during sliding mechanics. The influence of site specificity on the amount of debris and on frictional forces of the first molar tubes could not be demonstrated. CLINICAL SIGNIFICANCE: Molar tubes should be cleaned, before and during sliding mechanics, in order to minimize friction.

Unusual vanishing interstitial lymphatic "pearls" in a patient presenting with extensive interstitial and mediastinal MDCT features of acute cardiogenic failure related to bradycardia and mitral regurgitation.

Thoracic multidetector computed tomography-MDCT-was simultaneously performed during emergency abdominal CT in a patient presenting with abdominal pain and acute cardiogenic edema related to sick sinus syndrome and mitral prolapse with regurgitation. A constellation of severe but completely reversible interstitial and mediastinal features was found comprising pleural effusions, diffuse alveolar ground glass, thickening of the bronchial walls and septal lines, hazy infiltration of the mediastinal fat, and enlarged lymphatic nodes. Multiple atypical hypodense nodular "pearls" were also found. These oval shape or fusiform pearls were distributed along the thickened septal lines and disappeared completely after treatment. The hypothesis of transient lymphatic ectasia or lakes is proposed for these never previously described abnormalities.

Comparison of the accuracy of bracket axial positioning with and without radiographic support and according to practitioner experience: A three-dimensional study.

INTRODUCTION: Accurate bracket positioning remains challenging. To avoid angulation errors, some recommend examining the panoramic radiograph during bonding. However, it can cause distortions. Cone-beam computed tomography (CBCT) provides a more precise panoramic reconstruction but with higher radiation doses. The main objective of this study is to compare the accuracy of axial positioning between direct bonding without radiography, with conventional panoramic radiograph, and with panoramic reconstruction from CBCT. The secondary objectives are to evaluate positioning accuracy of each tooth and to assess the influence of practitioner level of experience. METHODS: Thirty practitioners, divided into two groups based on their experience performed direct bonding on a model thrice: without radiography, then with the conventional panoramic radiograph, then with the panoramic reconstruction from CBCT. Models were scanned, and angulation errors were measured using OrthoAnalyzer. Values were compared using the Friedman's test followed by the Bonferroni correction for multiple comparisons (P-value = 0.05). RESULTS: For the low level of experience group, angulation errors were significantly greater than the accepted limit without radiographic reference, and significantly lower with CBCT reconstruction. For the high level of experience group, angulation errors were significantly lower than the accepted limit for the three bonding methods. For every tooth, using the panoramic reconstruction from CBCT as a reference, was the most accurate method, regardless of the level of experience. More experienced practitioners made fewer errors for the three methods. CONCLUSIONS: Panoramic reconstruction from CBCT is the most accurate method to limit angulation errors during direct bonding. Conventional panoramic radiography remains a reliable tool if used with caution. Bonding without any radiographic reference should be avoided especially for less experienced practitioners.

In-vivo durability of Pro Seal in patients with fixed orthodontic appliances: A controlled clinical trial.

BACKGROUND: This clinical trial aimed at studying the durability of an orthodontic sealant (Pro Seal) used on tooth surfaces for protection against white spot lesions. METHODS: A total of 35 patients (18 females, 17 males; 17.57 ± 1.36 years) were recruited. Eligibility criteria included healthy patients of both sexes (age > 14 years), absence of labial caries, absence of defective enamel, absence of extensive restorations, and optimum oral hygiene. The participants received a single application of Pro Seal on the bonded teeth. The sealant covered the labial enamel surrounding the brackets. Participants were recalled monthly after sealant application, during which sealant layers were evaluated using an ultraviolet lamp. The assessment was realized using an index similar to the adhesive remnant index (ARI). RESULTS: A total of 30 participants completed the trial. ARI values dropped significantly (P < 0.001) and reached <1.5 at T1 on the index used. An ARI value of 2 was chosen as the threshold below which a tooth presented an insufficient sealant layer. The right and left sides of both jaws did not show any statistically significant difference (P > 0.05). ARI values of homolateral teeth revealed few statistically significant differences between upper and lower teeth. No statistically significant difference between the two sexes (P > 0.05) existed. No harm or disturbance was reported by any of the participants. CONCLUSIONS: This study demonstrated that a single application of Pro Seal is effective for 4 weeks and should be renewed monthly. No interjaw, intrajaw, or intersex significant differences were found.

Effect of Different Surface Treatments on the Shear Bond Strength of Metal Orthodontic Brackets Bonded to CAD/CAM Provisional Crowns.

BACKGROUND: The aim of this study was to find the best surface treatment for CAD/CAM provisional crowns allowing the optimal bond strength of metal brackets. METHODS: The sample consists of 30 lower bicuspids and 180 provisional crowns. The provisional crowns were randomly divided into six different groups. Orthophosphoric acid etching (37%) was applied to 30 lower bicuspids. The provisional crowns had undergone different surface treatments. Group 1: No treatment (Control Group). Group 2: Diamond bur. Group 3: Sandblasting. Group 4: Plastic Conditioner. Group 5: Diamond bur and Plastic Conditioner. Group 6: Sandblasting and Plastic Conditioner. The brackets in all groups were identically placed using Transbond XT® Primer and Transbond XT® Paste. Then, the entire sample underwent an artificial aging procedure, and a measurement of the bond strength was conducted. After debonding, the surface of the crowns was examined to determine the quantity of the adhesive remnant. RESULTS: Bonding to natural crowns recorded the highest average, followed by the averages of groups 5 and 6. However, group 1 recorded the lowest average. Groups 2 and 4 had very close averages, as well as groups 5 and 6. A statistically significant difference between the averages of all groups was recorded (p < 0.001) except for groups 2 and 4 (p = 0.965) on the one hand, and groups 5 and 6 (p = 0.941) on the other hand. DISCUSSION: The bonding of brackets on provisional crowns is considered a delicate clinical procedure. In fact, unlike natural crowns, the orthophosphoric acid usually used does not have any effect on the surface of provisional crowns. CONCLUSIONS: Using a diamond bur combined with the plastic conditioner and sandblasting combined with that same product resulted in a bond strength close to natural crown.

Factors influencing the perception of profile beauty in Class III dental compensation: A comparative cross-sectional study according to three categories of assessors.

INTRODUCTION: The main objective of this study was to evaluate the different factors influencing the perception of female profile facial beauty in Class III patients with protruded mandible that can be treated with orthodontic dental compensation: (1)severity of the protrusion, (2) the upper incisors inclination and (3) the presence of jawlines. The secondary objective was to determine if the rater's gender and profession played a role in the assessment of the preferred profile. METHODS: A normal and smiling photographs of a female subject with normal facial and skeletal profile criteria were digitally manipulated to obtain 3 different mandibular sagittal positions: 0mm, +4mm and +8mm. Each position of the chin was evaluated with the presence or not of jawlines. In the smiling profiles, the same chin modifications were scored, and the maxillary incisor inclination was changed from 0 to +10 degrees with 5 degrees increments. A total of 320 raters (107 dentists, 103 orthodontists and 110 laypeople) scored the attractiveness of the different images using a Visual Analogue Scale. The limit of statistical significance was P<0.05. Generalized estimating equation (GEE) models were conducted to assess the predictors of variations in ratings within each set of photos, as well as the interactions of predictors where adjusted odds ratios (aOR) and their 95% confidence intervals were calculated and reported. RESULTS: In the profiles without a smile, image +4mm chin (Class III treated by compensation) and image +8-mm mandible (Class III not treated) were selected as the most and least attractive images, respectively, by almost all groups with no difference. The presence of jawlines has a positive role in facial attractiveness. In the smiling profiles, all the examiners showed a preference for image +4-mm chin and a slight protrusion of maxillary incisors (+5 degrees). No significant difference was found between genders in this study. CONCLUSIONS: Class III treated by compensation (+4mm) are more attractive than non-treated Class III (+8mm) by almost all groups with no difference. The presence of jawlines has a positive role in facial attractiveness. In the smiling profiles, all the examiners showed a preference for image +4-mm chin and a slight protrusion of maxillary incisors (+5 degrees). Orthodontists older than 50 years old are aware of the difficulty to treat a skeletal Class III and tend to accept it due to their long career experience. No significant difference was found between genders in this study.

Meta-analysis of personal and familial co-occurrence of Attention Deficit/Hyperactivity Disorder and Bipolar Disorder.

BACKGROUND: Attention Deficit Disorder / Hyperactivity (ADHD) and Bipolar Disorder (BD) are highly comorbid disorders. Studies have raised the hypothesis of shared genetic, neurobiological, and clinical factors. This would entail an excess risk of co-occurrence of both disorders. OBJECTIVE: We present the first meta-analysis of individual and familial associations between ADHD and BD. METHODS: From 2688 references, 59 were included, with a total of 550,379 ADHD patients, 57,799 BD patients and 12,608,137 controls. RESULTS: Personal history of ADHD increased the risk of BD (OR = 6.06), and conversely individuals with BD had an increased risk of ADHD (OR = 8.94). First-degree relatives of ADHD patients had an increased risk of BD (OR = 1.94). Offspring of individuals with BD had a higher risk for ADHD (OR = 2.33). Finally, first-degree relatives of BD patients had an increased risk of ADHD (OR = 2.71). CONCLUSION: We show a clear epidemiological overlap between ADHD and BD, as well as a strong familial association which advocates in favor of a more systematic screening.

Emotional and behavioral changes in French children during the COVID-19 pandemic: a retrospective study.

COVID-19 outbreak caused severe disruptions in daily life, partly due to limitations implemented to prevent the spreading. In France, it included school closures during a national lockdown, then a reopening of schools, with access depending on viral status of students and teachers. Those changes had an impact on children's mental health. We conducted an online cross-sectional study using a parental self-administered survey in December 2021 to explore the emotional and behavioral changes (EBC) during this 5th wave (W5) and retrospectively since the first one (W1) in their children and their multidimensionality with principal factor analysis (PCA) and stability analysis. Out of 4552 parent responders, 62.4% (n = 2839) noticed negative EBC during W1 and 54.1% (n = 2462) during W5 of the pandemic. Only 10.0% of the responders noticed negative EBC at W1 but not during the W5. In younger children (3-6 years old) with significant EBC, PCA revealed three main dimensions at W1 and W5: restlessness, depression and anxiety. In older children (7-13 years old), PCA showed partially similar dimensions: depression-suicidality, anxiety and withdrawal. Almost all correlations between dimensions at W1 and W5 were significantly positive. Every EBC was stable across waves, except for one. Recall bias concerning the EBC during W1 and lack of data concerning parental mental health should be taken into account. Our stability analysis found a strong correlation between dimensions at W1 and W5. Our results highlighted the impact of the COVID-19 outbreak on children's mental health and the predictive aspect of its early deterioration.