How COVID-19 Phases Have Impacted Psychiatric Risk: A Retrospective Study in an Emergency Care Unit for Adolescents.

Dramatic events during the COVID-19 pandemic have acutely impacted the psychosocial environment worldwide, with negative implications for mental health, particularly for more vulnerable children and adolescents with severe psychiatric illnesses. Some data suggest that the pandemic waves may have produced different psychopathological consequences, further worsening in the second phase of the pandemic, compared to those in the first lockdown, soon after March 2020. To test the hypothesis of a further worsening of psychiatric consequences of COVID-19 in the second lockdown compared to the first lockdown, we focused our analysis on a consecutive sample of youth referred to a psychiatric emergency unit for acute mental disorders in the time period between March 2019-March 2021. The sample, consisting of 241 subjects (123 males and 118 females, ranging in age from 11 to 17 years), was divided into three groups: Pre-Lockdown Group (PLG, 115 patients); First Lockdown Group (FLG, 65 patients); and Second Lockdown Group (SLG, 61 patients). Patients in the SLG presented more frequently with non-suicidal self-injuries (NSSIs), suicidal ideation, and suicidal behavior, while no significant differences in self-harm were found between PLG and FLG. Eating disorders were more frequent in both the FLG and SLG, compared to the PLG, while sleep problems were higher only in the SLG. Furthermore, patients in the SLG presented with more frequent psychological maltreatments and neglect, as well as with psychiatric disorders in the parents. Adverse traumatic experiences and internalizing disorders were significantly associated with an increased risk of suicidality. Intellectual disability was less represented from the PLG to SLG, and similarly, the rate of ADHD was lower in the SLG. No differences were found for the other psychiatric diagnoses. This information may be helpful for a better understanding and management of adolescents with severe emotional and behavioral disorders after the exposure to long-lasting collective traumas.

A novel multidimensional questionnaire for the assessment of emotional dysregulation in adolescents: Reactivity, Intensity, Polarity and Stability questionnaire-youth version (RIPoSt-Y).

BACKGROUND: The failure to regulate emotions, namely emotional dysregulation (ED), is a relevant construct in adolescent psychiatry, in terms of prognostic and developmental implications. We developed and validated a novel self-report questionnaire for the assessment of ED, the RIPoSt-Y, both in clinical and non-clinical samples. METHODS: Items selection and subscales construction were conducted on healthy controls (n=374), while test-retest reliability was evaluated in a subsample (n=72); internal consistency was examined both in the control group and in two clinical samples, respectively including patients with Bipolar Spectrum Disorders (BSD; n=44) and ADHD (n=34). Construct, concurrent and convergent validity were also assessed. RESULTS: Thirty-one items were finally retained, and three subscales were identified (Affective Instability, Emotional Reactivity, Interpersonal Sensitivity). Test-retest was significant for each subscale with moderate-to-good correlations, and internal consistency showed good-to-excellent coefficients. Construct validity was supported by significant differences between patients and controls and gender-related differences. Concurrent validity was confirmed through significant associations with two subscales of the CHT-Q, while convergent validity proved to be significant with the CBCL/YSR dysregulation-profile. Cut-offs were also computed to discriminate clinically significant scores of ED. LIMITATIONS: The use of a school-based survey to recruit controls could have biased our results; gender distributions between clinical and non-clinical samples were significantly different. CONCLUSIONS: Our novel questionnaire proved to be a valid and reliable tool able to assess the presence of ED in youths and to characterize this fundamental construct in its multidimensional facets.

An Exploratory Study of Emotional Dysregulation Dimensions in Youth With Attention Deficit Hyperactivity Disorder and/or Bipolar Spectrum Disorders.

Emotional dysregulation (ED) is currently the most frequently used term to describe children with an impaired regulation of emotional states. Recent research studies speculate whether ED may be a neurodevelopmental disorder itself, a shared risk factor, or a common key feature of several psychiatric disorders, including, among others, attention deficit hyperactivity disorder (ADHD), and bipolar spectrum disorders (BSD). The association between ADHD and ED is one of the main reasons of misconceptions in the definition of boundaries between ADHD and BSD, leading to the frequent misdiagnosis of ADHD as BSD. Since ED is a multidimensional concept, a novel instrument-the Reactivity, Intensity, Polarity and Stability (RIPoSt) scale-was recently developed to assess the different dimensions of ED, which could help in detecting specific ED profiles in clinical youths. Our study included 154 patients, aged 13.8 ± 2.3 years, diagnosed with either ADHD, BSD, or comorbid condition, and a school-based sample of 40 healthy control (HC) adolescents, aged 12.5 ± 1.2 years. The RIPoSt scale and the Child Behavior Checklist were administered to both groups. Our results indicate that affective instability and negative emotionality subscales, as well as negative emotional dysregulation, are higher in BSD, both pure and comorbid with ADHD, while emotional impulsivity is higher in the comorbid condition and similar in the ADHD and BSD alone group; all clinical groups scored higher than HC. Conversely, positive emotionality is similar among clinical groups and within them and HC. Our findings also support the validity of the RIPoSt questionnaire, since the instrument proved to have good-to-excellent internal consistency, and strongly significant positive correlations were found with the CBCL-Dysregulation Profile, which is a commonly used, indirect measure of ED. Hence, the five subscales of the RIPoSt can be reliably used as an effective tool to study the emotional dysregulation in different clinical conditions, to help disentangle the complex relationship between ADHD and juvenile BSD and to provide clinicians with crucial evidence for better diagnostic characterization and therapeutic indications.

Behavioural and Emotional Changes during COVID-19 Lockdown in an Italian Paediatric Population with Neurologic and Psychiatric Disorders.

On 11 March 2020, a national lockdown was imposed by the Italian government to contain the spread of COVID19 disease. This is an observational longitudinal study conducted at Fondazione Stella Maris (FSM), Italy to investigate lockdown-related emotional and behavioural changes in paediatric neuropsychiatric population. Families having children (1.5-18 years) with neuropsychiatric disorders referred to FSM have been contacted and proposed to fulfil two online questionnaires (General questionnaire and Child Behaviour Check List (CBCL)) to (i) compare (paired two-sample t-tests) the CBCL scores during lockdown with previous ones, and (ii) investigate the influence (multiple linear regression models) of variables such as age, diagnosis grouping (neurological, neurodevelopmental, emotional, and behavioural disorders) and financial hardship. One hundred and forty-one parents fulfilled the questionnaires. Anxiety and somatic problems increased in 1.5-5 years subpopulation, while obsessive-compulsive, post-traumatic and thought problems increased in 6-18 years subpopulation. In the regression models, younger age in the 1.5-5 years subpopulation resulted as "protective" while financial hardship experienced by families during lockdown was related to psychiatric symptoms increasing in the 6-18 years subpopulation. Some considerations, based on first clinical impressions, are provided in text together with comments in relation to previous and emerging literature on the topic.

Metabolic effects of early protein undernourishment and renourishment in wistar rats / Efeitos metabólicos da subnutrição proteica pré-natal e renutrição em ratos wistar

Malnutrition remains an important public health condition by affecting mostly children. The present study aimed to examine the effects of prenatal protein undernourishment and postnatal renourishment on the metabolism of pre-adult animals. Forty-five male Wistar rats originating from different litters were used. The Nourished (N, n=15) and Undernourished (U, n=30) groups were maintained on proteic and hypoproteic diets (20% and 5% casein, respectively) from the intrauterine phase until the end of the experiment. The Renourished group (R) contained 15 animals, randomly chosen from U group, that consumed the N diet beginning on day 21 (weaning). All groups were maintained until day 60. The experimental data was acquired daily for body weight, feed and water intake, feces and urine excretion. Data analysis was made with the total results and the ratio between them. The U group animals developed uniformly sparse hair late and experienced intense sweating, features that were not observed during the experiment in the R and N animals groups. The R group had the largest weight gain and feed and water intake ratio/weight at experimental period, followed by the N group animals. The final body weight and food intake decreased gradually in the order N-R-U, but none of the other parameters showed a statistical difference between the N and R animals. Compared to groups N and R, the U group animals consumed 90% and 81% more food and water, respectively. Protein undernourishment induced metabolic dysfunction in the U group animals. The similarity in the experimental parameters of the N and R groups suggests that an early feeding correction was effective in reestablishing the organic functions of the R group animals.

A subnutrição ainda é uma condição importante na saúde pública por afetar principalmente crianças. O presente estudo tem o objetivo de avaliar os efeitos da subnutrição pré-natal e renutrição pós-natal no metabolismo de ratos jovens. Quarenta e cinco ratos Wistar machos originados de diferentes ninhadas foram utilizados. O grupo Nutrido (N, n=15) e Subnutrido (U, n=30) foram mantidos sob dieta protéica e hipoprotéica (20% e 5% de caseína, respectivamente) desde a fase intrauterina até o final do experimento. O grupo Renutrido (R) conteve 15 animais aleatoriamente selecionados do grupo U para consumir a dieta protéica a partir do dia 21 pós-natal (desmame). Todos os grupos foram mantidos até o dia 60. Os animais do grupo U desenvolveram pelos tardiamente, uniformemente escassos e sudorese intensa, fato não visto ao longo do experimento nos animais R e N. Os animais R obtiveram o maior ganho de peso, fração ingestão por peso e consumo de água por peso no período experimental, seguido pelo grupo N. O peso corporal final e a ingestão final de alimento ficaram decrescentes na ordem N-R-U, enquanto que para todos os outros parâmetros não houve diferença estatística entre o animal N e R. Comparativamente ao grupo N e R, o grupo U consumiu 90% e 81% a mais de alimento e água, respectivamente. A subnutrição proteica induziu disfunção metabólica nos animais U. A semelhança nos parâmetros experimentais entre o grupo N e R sugere que a correção precoce da alimentação foi eficaz no retorno das funções orgânicas dos animais R.

Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression.

UNLABELLED: The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin. OBJECTIVES: The present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment. MATERIAL AND METHODS: The nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed. RESULTS: The area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups. CONCLUSIONS: Protein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs.

Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression

The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin. Objectives The present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment. Material and Methods The nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed. Results The area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups. Conclusions Protein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs. .

Morphological changes in distant muscle fibers following thermal injury in Wistar rats.

PURPOSE: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45% of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45% of the body surface.

Morphological changes in distant muscle fibers following thermal injury in Wistar rats / Alterações morfológicas das fibras musculares de um músculo distante da lesão térmica em ratos Wistar

PURPOSE: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45 percent of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45 percent of the body surface.

OBJETIVO: A lesão térmica conduz o organismo a processos catabólicos a fim de reparar a área lesada. O propósito do presente estudo foi avaliar os efeitos da lesão térmica por escaldadura na morfologia das fibras musculares de um músculo distante da lesão. MÉTODOS: Foram utilizados 30 ratos Wistar, divididos em: Grupo submetido à lesão térmica por escaldadura (S) e Grupo Controle (C). A escaldadura foi provocada em 45 por cento da superfície corporal dos animais e padronizada pelo peso corpóreo. A eutanásia ocorreu nos períodos pós-lesão de quatro, sete e 14 dias. Retirou-se a parte média dos músculos gastrocnêmio medial os quais foram submetidos à técnica histológica de Hematoxilina-Eosina e Picrosírius. RESULTADOS: O aspecto poligonal das fibras musculares, com núcleos periféricos, bem como a distribuição eqüidistante das mesmas, característico das descrições da musculatura normal, verificado nos animais do grupo C não foi uma constante nas fibras do músculo dos animais do grupo S. Nestes, muitas fibras exibiram contorno arredondado, diferentes intensidades de marcação bem como maior distanciamento entre as mesmas. Observou-se ainda aumento substancial da quantidade de tecido conjuntivo no grupo S. CONCLUSÃO: Houve alteração da morfologia do músculo distante da lesão como resposta à lesão térmica de 45 por cento em modelo experimental.

Estimating the length density of convoluted tubular systems - II: comparative analysis using five different methods.

An artificial convoluted tubular system with precise predefined parameters was created. It was stereologically analyzed in order to preview the potential probability to introduce errors when applied to biological systems like testicular tubes or glomerule like structures. The length of the convoluted tubules more frequently analyzed was estimated by five different methods. The analytical methods were based on both the number of tubule transections, which is related to the transection area and/or organ volume, and the axis length of an ideal cylinder. Tubular systems were analyzed with or without consideration of the transection shape. When shape was considered, two methods were compared: one evaluating the major and minor axes from elliptical profiles, and the other the crosses between parallel lines of a test system superimposed on circular, elliptical, or more complex profiles. Comparison of the five methods revealed different estimations of the length in relation to the pre-determined model, which varied from an 11.8% overestimation to a 39% underestimation. The fractionator method was proposed as alternative to diminish the work overload when counting intersections between lines of test systems and transection profiles. The results with the fractionator are very promising concerning the application of the method in laboratories of pathology.

The relative effects of severe burn injury and pre- and post-natal protein deprivation on mandibular condyle morphology.

The mandible has a mixed embryological origin, and its growth is associated with the secondary cartilage of the condyle process (CP). In this area, growth depends on an array of intrinsic and extrinsic factors that influence protein metabolism. In the present study, we used an adolescent rat model to evaluate the growth and development of the CP under conditions of pre- and postnatal protein deficiency, combined with or without the stress of severe burn injury (BI). We found that protein deficiency severely undermined the growth of the CP, by altering the thickness of its constituent layers. BI is also capable of affecting CP growth, although the effect is less severe than protein deficiency. Interestingly, the summed effect of protein deficiency and BI on the CP is less severe than protein deficiency alone. A possible explanation is that the increased carbohydrates in a hypoproteic diet stimulate the production of endogenous insulin and protein synthesis, which partially compensates for the loss of lean body mass caused by BI.

The connective tissue of the adductor canal--a morphological study in fetal and adult specimens.

The adductor canal is a conical or pyramid-shaped pathway that contains the femoral vessels, saphenous nerve and a varying amount of fibrous tissue. It is involved in adductor canal syndrome, a claudication syndrome involving young individuals. Our objective was to study modifications induced by aging on the connective tissue and to correlate them to the proposed pathophysiological mechanism. The bilateral adductor canals and femoral vessels of four adult and five fetal specimens were removed en bloc and analyzed. Sections 12 microm thick were obtained and the connective tissue studied with Sirius Red, Verhoeff, Weigert and Azo stains. Scanning electron microscopy (SEM) photomicrographs of the surfaces of each adductor canal were also analyzed. Findings were homogeneous inside each group. The connective tissue of the canal was continuous with the outer layer of the vessels in both groups. The pattern of concentric, thick collagen type I bundles in fetal specimens was replaced by a diffuse network of compact collagen bundles with several transversal fibers and an impressive content of collagen III fibers. Elastic fibers in adults were not concentrated in the thick bundles but dispersed in line with the transversal fiber system. A dynamic compression mechanism with or without an evident constricting fibrous band has been proposed previously for adductor canal syndrome, possibly involving the connective tissue inside the canal. The vessels may not slide freely during movement. These age-related modifications in normal individuals may represent necessary conditions for this syndrome to develop.

Pericial analysis of a dental element found inside food used for human consumption.

The field of forensic dentistry embodies the human identification in a lot of conditions. A case is described when a tooth-like object was found in a pork sausage. A lawsuit was filed against the food company and the possible dental element was analysed. The tests used to analyze the case were: scanning electronic microscopic exam, radiographic exam and compared anatomy. The results confirmed that the object found in the sausage pack was a dental element from an adult pig; which had the potential for problems like asphyxia or contamination. The case illustrates one facet of forensic dentistry in Brazil.

A simple method for estimating the length density of convoluted tubular systems.

We present a new method for estimating the length density (Lv) of convoluted tubular structures exhibiting an isotropic distribution. Although the traditional equation Lv=2Q/A is used, the parameter Q is obtained by considering the collective perimeters of tubular sections. This measurement is converted to a standard model of the structure, assuming that all cross-sections are approximately circular and have an average perimeter similar to that of actual circular cross-sections observed in the same material. The accuracy of this method was tested in eight experiments using hollow macaroni bent into helical shapes. After measuring the length of the macaroni segments, they were boiled and randomly packed into cylindrical volumes along with an aqueous suspension of gelatin and India ink. The solidified blocks were cut into slices 1.0 cm thick and 33.2 cm2 in area (A). The total perimeter of the macaroni cross-sections so revealed was stereologically estimated using a test system of straight parallel lines. Given Lv and the reference volume, the total length of macaroni in each section could be estimated. Additional corrections were made for the changes induced by boiling, and the off-axis position of the thread used to measure length. No statistical difference was observed between the corrected estimated values and the actual lengths. This technique is useful for estimating the length of capillaries, renal tubules, and seminiferous tubules.

Correlaçöes entre medidas da coroa e a espessura do esmalte nas faces proximais de incisivos superiores permanentes humanos / Correlation between crown measurements and enamel thickness from proximal aspects of human permanent upper incisors

Introduçäo: A presente pesquisa desenvolveu-se devido à necessidade de uma determinaçäo precisa da espessura do desgaste do esmalte à altura do ponto para a obtençäo de parâmetros científicos confíaveis. Métodos: Os diâmetros máximos mésio-distal, cérvico-incisal e vestíbulo-lingual em dentes incisivos superiores foram determinados bem como medidas da espessura do esmalte nas faces proximais de incisivos superiores foram obtidas com o auxílio de um perfilômetro. Resultados: Verificou-se que os diâmetros mésio-distal, cérvico-incisal e vestíbulo-lingual säo significativamente maiores nos incisivos centrais superiores do que nos incisivos laterais superiores e que a espessura do esmalte na face distal, independentemente do lado (direito ou esquerdo) e do dente (central ou lateral), é significativamente maior que a espessura do esmalte da face mesial. Conclusöes: Correlaçöes positivas, estatisticamente significativas, foram encontradas entre a espessura do esmalte na fase distal do incisivo lateral superior esquerdo e o correspondente diâmetro vestíbulo-lingual; entre a espessura do esmalte na face mesial do incisivo central superior esquerdo e o correspondente diâmetro mésio-distal

Conventional scanning electron microscopic study of the submandibular gland of the rat

The submandibular gland of rats was treated with HC1-collagenase and NaOH methods which remove respectively, the collagen fibers and cellular components of acinar and ductal structures. The results revealed that the acini are oval in shape and surrounded by basal lamina and fine fibrilar structures. The fractured surface revealed clearly the lobuli, the interlobular spaces containing the collagen fiber bundles and the acini formations of submandiblar glands. Numerous acini of differents diameters are seen. The surfaces of striated ductus showed the original disposition of collagen fiber bundles belonging to the capsular elements.

Compatibilidade biológica de materiais odontológicos fotopolimerizáveis e ativados quimicamente, utilizados no forramento de cavidades (Baseline e Baseline VLC) / Biological compatibility of foto and auto activated dental materials used as cavity liners (Baseline VLC and Baseline)

O ionômero de vidro é um material relativamente novo, que apresenta propriedades como adesäo química à estrutura dental e liberaçäo de flúor. Em virtude dessas propriedades, esse material vem sendo amplamente pesquisado e cada vez mais utilizado na clínica odontológica. Assim, o objetivo desta pesquisa foi avaliar comparativamente o potencial irritativo em nível I de compatibilidade biológica, de dois materiais ionoméricos indicados como forradores em preparos cavitários. Foram utilizados 40 animais divididos equitativamente em dois grupos de 20, para os períodos de 3, 7, 14, 28 e 60 dias. Os materiais mostraram-se como irritantes do tecido conjuntivo subcutâneo do rato, na seguinte ordem: Grupos I (Baseline VLC) e II (Baseline); houve evoluçäo no processo inflamatório com proliferaçäo fibroangioblástica ao longo dos períodos, chegando ao fim desses com colagenizaçäo intensa; a atividade macrofágica foi constante e exercida principalmente por fagócitos mononucleares e menos acentuadamente por células gigantes multinucleadas sobre partículas do material; até conclusäo da ativaçäo de reaçäo do material, há possibilidade de dispersäo do material exacerbando o quadro inflamatório, fazendo persistir compacta atividade macrofágica. As laterais dos tubos de polietileno caracterizaram o Grupo III como controle

Compatibilidade biológica de materiais odontológicos fotopolimerizáveis e quimicamente ativados, utilizados como forradores cavitários (Time Line e Hidro C) / Biocompatibility of light-cured materials and auto-cured, used as cavities lining (Time Line and Hidro C)

A biocompatibilidade de dois materiais odontológicos usados como forradores cavitários, sendo um fotopolimerizado (Time Line) e o outro quimicamente ativado (Hidro C), foi estudada por meio de implantes subcutâneos em ratos. Os implantes foram feitos por tubos de polietileno com 10mm de comprimento e 1,5mm de diâmetro interno, e uma das extremidades foi fechada a quente. Estes tubos foram preeenchidos com os materiais em teste e inseridos em bolsas cirúrgicas no dorso dos animais, que foram sacrificados em períodos pós-operatórios de 3, 7, 14, 28 e 60 dias. Os cortes de pele foram realizados no longo eixo do tubo, tornando possível analisar a provável alteraçäo tecidual provocada pelos materiais em teste junto à abertura tubular, área principal de análise, assim como observar as características do tecido da sua superfície lateral e extremidade fechada. Os tubos, incluídos em parafina, foram corados com H/E e revelaram que a reaçäo inflamatória inicialmente intensa e de predomínio mononuclear foi em todos os períodos superior para o Time Line, sendo ampla a cápsula formada junto à abertura tubular. Com o decorrer dos períodos a reaçäo inflamatória diminuiu, o mesmo ocorrendo com o cone capsular, chegando no último período a formar nesta área principal de análise um tecido fibroso (discretas células inflamatórias) que manteve continuidade com a cápsula fibrosa da superfície lateral do tubo