RESUMO

Hemodynamic forces are related to pathological variations of the cardiovascular system, and numerical simulations for fluid-structure interaction have been systematically used to analyze the behavior of blood flow and the arterial wall in aortic aneurysms. This paper proposes a comparative analysis of 1-way and 2-way coupled fluid-structure interaction for aortic arch aneurysm. The coupling models of fluid-structure interaction were conducted using 3D geometry of the thoracic aorta from computed tomography. Hyperelastic anisotropic properties were estimated for the Holzapfel arterial wall model. The rheological behavior of the blood was modeled by the Carreau-Yasuda model. The results showed that the 1-way approach tends to underestimate von Mises stress, displacement, and strain over the entire cardiac cycle, compared to the 2-way approach. In contrast, the behavior of the variables of flow field, velocity, wall shear stress, and Reynolds number when coupled by the 1-way model was overestimated at the systolic moment and tends to be equal at the diastolic moment. The quantitative differences found, especially during the systole, suggest the use of 2-way coupling in numerical simulations of aortic arch aneurysms due to the hyperelastic nature of the arterial wall, which leads to a strong iteration between the fluid and the arterial wall.

Assuntos

RESUMO

OBJECTIVE: Present a gnathodynamometer design that increases patient comfort, precision, and/or ease for the operator during bite force tests. MATERIALS AND METHODS: A bite tip capable of pivoting 180° was tested on senior dental students in a double-blind trial. The tests were performed in teeth 11 and 16 with the bite tip on the long axis of the clamp and at an angle of 90° to the clamp. The sample was composed of 24 students, 13 males and 11 females, randomly divided into two groups: the operator group (OP), which was composed of 12 students, 7 males and 5 females, and the test group (TI), which was composed of 12 students, 6 males and 6 females. The operator and participants were asked to evaluate comfort and precision/ease in positioning the bite tip by attributing scores from 0 (total discomfort) to 10 (total comfort) during the test. RESULTS: No difference was noted in tooth 11 (P > 0.05). In tooth 16, there was a statistically significant improvement (P < 0.01) for the participants tested and the operator using the pivoting bite tip. CONCLUSIONS: The pivoting bite tip showed no difference in the comfort of the participants and operator precision when testing incisors; however, the tip showed a difference for both conditions in the molar region. The gnathodynamometer geometry showed good results in participant comfort and operator precision when used in bite force tests of the incisors and molars. Further investigations are needed to confirm whether these improvements influence the mean value and maximum bite force measurement. CLINICAL RELEVANCE: Bite force measurement is a method for obtaining important data to check the functional conditions of the stomatognathic system. With the aging of the world population, it has become important to check the quality of life during aging. The pivoting bite tip improves the comfort and precision of bite tests for the participants tested and for the operator, respectively.

Assuntos

RESUMO

PURPOSE: Caeski is a keyboard with 12 vibrating keys that connects to an application via smartphone. This assistive technology aims to facilitate the communication of persons with deafblindness in presential contexts or with people who can be anywhere in the world. The purpose is to present this assistive technology and analyse the viability of its use through tests with eleven persons with deafblindness. MATERIALS AND METHODS: The study design consisted of ten days of testing with eleven persons with deafblindness and five interpreters who had the function of passing the information about the content of the tests. RESULTS: The tests showed that most participants were able to communicate through Caeski. In addition, the tests showed the need to add the function of repeating the reception of information via vibration to confirm the understanding. The results demonstrated the need for more training time to improve the learning of accented words and long sentences. Therefore, training time and previous contact with technological devices are factors that influence the result of the tests. CONCLUSION: The use of Caeski is feasible and as future perspectives, this assistive technology can be used in association with similar assistive technologies such as Perkins Machine and Braille Line, preventing possible tactile overloads. In addition, can be applied in the educational context, from literacy to university. Studies with longer training time should be conducted to confirm the results. The implications for rehabilitation:Social interactions, presential and online, with deafblind and non-deafblind persons anywhere in the world.Literacy and cognitive development of persons with deafblindness.Digital inclusion for occupational, school or academic contexts.

RESUMO

Periodontitis is an infectious disease characterized by the destruction of supporting tissues. Antimicrobial photodynamic therapy (aPDT) has been proposed as an improved method for eliminating microorganisms. Its efficiency depends on the correct use of physical and chemical parameters. Thus, these parameters and their relations were evaluated in this study with the purpose of establishing lethal conditions for combating bacterial agents. Diode lasers and light-emitting diodes (LEDs) were characterized to evaluate the absorption profile and resonance of methylene blue (MB) and toluidine blue O (TBO). The relations between light energy density and photosensitizer absorption were determined. Two methodologies were used to evaluate the effects of aPDT against Aggregatibacter actinomycetemcomitans. LED light exhibited a broad emission spectrum with a peak light wavelength of 637 nm and 99% purity. The resonance intensity of MB was higher with diode laser irradiation, and TBO showed higher resonance intensity with LED irradiation. There was no difference in the absorption profile of photosensitizers using diode lasers or LEDs, and variations in power density did not result in an increasing or decrease in light absorption. A. actinomycetemcomitans was susceptible to photodynamic processes. Emission spectra and peak light wavelengths of light sources combined with the absorption profiles of photosensitizers were the main parameters involved in determining the efficiency of photodynamic effects. Power density did not alter the light absorption of photosensitizers. The association between adequate irradiation characteristics and photosensitizer absorption results in complete inactivation of A. actinomycetemcomitans. In addition, the bactericidal effect was not altered by an increase in energy densities.

Assuntos

RESUMO

This study aimed to validate the Brazilian version of the RMS Tactile Scale (B-RMS-TS) in children and adolescents with visual impairment. Ten visually impaired children and adolescents between 10 and 17 years old of an Educational Center for Visually Impaired People answered the verbalized Dental Anxiety Scale (DAS), and the DAS in Braille to evaluate their dental anxiety levels. B-RMS-TS construct validity was assessed by convergent and discriminant validity. Convergent validity was tested in two ways: Pearson's correlation between the B-RMS-TS and the overall anxiety question; Pearson's correlation between B-RMS-TS and verbalized DAS and DAS in Braille. B-RMS-TS reliability was measured by internal consistency (Cronbach's alfa and McDonald's omega) and test-retest reliability (ICC). B-RMS-TS was moderately correlated to the overall anxiety question (r=0.493;p=0.147). B-RMS-TS showed excellent correlation with verbalized DAS (r=0.971;p<0.001) and DAS in Braille (r=0.934;p<0.011). B-RMS-TS was able to discriminate dental anxiety levels between male and female (p=0.008). The B-RMS-TS demonstrated excellent reliability (Cronbach's alpha=0.661, McDonald's omega=0.700 and ICC=0.987; 95%CI=0.817-0.999). B-RMS-TS is valid and reliable to measure dental anxiety levels in Brazilian children and adolescents with visual impairment.

Assuntos

RESUMO

The therapeutic benefits of LED in wound care have been reported since the 1990s. Nevertheless, studies directly related to the effects of LED phototherapy on the venous and arterial circulation and the healing process of pressure injuries are scarce in literature. Thus, the aim of this study was to evaluate the efficacy of a LED phototherapy prototype in participants with pressure injuries. In this pilot study 15 participants were randomized into three therapeutic groups. The experimental groups received applications of 630 and 940 nm LED three times a week for 8 weeks, with a dose of 6 J/cm2 in Group I. In group II, a dose of 8 J/cm2 in addition to the standard treatment. Group III (control group) received only daily standard treatment which consisted of cleaning the lesioned area with physiological solution, followed by application of an alginate hydrogel dressing over a period of 8 weeks. Pressure injuries were photographed and the area was measured by the Quantikov® image analyzer software. There was no statistically significant difference (p > 0.05) between the three groups when assessing the initial lesion area. At the end of 2 months, the median and interquartile ranges of the injuries were 5.90 (0.79-9.5) cm2 for group I, 0.54 (0.47-1.16) cm2 for group II and 26.76 (17.25-41.05) for group III. There was a statistically significant difference between treatment types (I x III and II x III) for pressure injuries over the 21 sessions. However, there was no significant difference between groups I x II that received different doses of LED phototherapy. The initial hypothesis was supported given that the combination of two wavelengths in the LED phototherapy with different doses may be helpful in accelerating the healing of pressure injuries.

Assuntos

RESUMO

Abstract This study aimed to validate the Brazilian version of the RMS Tactile Scale (B-RMS-TS) in children and adolescents with visual impairment. Ten visually impaired children and adolescents between 10 and 17 years old of an Educational Center for Visually Impaired People answered the verbalized Dental Anxiety Scale (DAS), and the DAS in Braille to evaluate their dental anxiety levels. B-RMS-TS construct validity was assessed by convergent and discriminant validity. Convergent validity was tested in two ways: Pearson's correlation between the B-RMS-TS and the overall anxiety question; Pearson's correlation between B-RMS-TS and verbalized DAS and DAS in Braille. B-RMS-TS reliability was measured by internal consistency (Cronbach's alfa and McDonald's omega) and test-retest reliability (ICC). B-RMS-TS was moderately correlated to the overall anxiety question (r=0.493;p=0.147). B-RMS-TS showed excellent correlation with verbalized DAS (r=0.971;p<0.001) and DAS in Braille (r=0.934;p<0.011). B-RMS-TS was able to discriminate dental anxiety levels between male and female (p=0.008). The B-RMS-TS demonstrated excellent reliability (Cronbach's alpha=0.661, McDonald's omega=0.700 and ICC=0.987; 95%CI=0.817-0.999). B-RMS-TS is valid and reliable to measure dental anxiety levels in Brazilian children and adolescents with visual impairment.

Resumo Este estudo objetivou validar a versão brasileira da escala tátil RMS (B-RMS-TS) em crianças e adolescentes com deficiência visual. Dez crianças e adolescentes deficientes visuais entre 10 e 17 anos de idade de um Centro Educacional para Pessoas Deficientes Visuais responderam a Dental Anxiety Scale (DAS) verbalizada, e a DAS em Braille para avaliar seus níveis de ansiedade odontológica. A validade de construto da B-RMS-TS foi avaliada pela validade convergente e discriminante. A validade convergente foi testada em duas maneiras: correlação de Pearson entre a B-RMS-TS e a questão geral de ansiedade; correlação de Pearson entre a B-RMS-TS e a DAS verbalizada e a DAS em Braille. A confiabilidade da B-RMS-TS foi mensurada pela consistência interna (alfa de Cronbach e ômega de McDonald).) e confiabilidade teste-reteste (CCI). A B-RMS-TS foi correlacionada moderadamente à questão geral de ansiedade (r=0,493;p=0,147). A B-RMS-TS mostrou correlação excelente com a DAS verbalizada (r=0,971;p<0,001) e com a DAS em Braille (r=0,934;p<0,011). A B-RMS-TS foi capaz de discriminar níveis de ansiedade odontológica entre meninos e meninas (p=0,008). A B-RMS-TS demonstrou confiabilidade excelente (alfa de Cronbach=0,661, ômega de McDonald=0,700 e CCI=0,987; 95%IC=0,817-0,999). A B-RMS-TS é válida e confiável para mensurar níveis de ansiedade odontológica em crianças e adolescentes brasileiros com deficiência visual.

Assuntos

RESUMO

In this study we apply methods to determine the tendency for thrombus formation in different central venous catheters (CVC) models associated with flow rate variation. To calculate the thrombogenic potential, we proposed a new numerical model of the platelet lysis index (PLI) equation. To compare the results of PLI and flow rate in different models of catheters, numerical calculations were performed on three different tips of CVC. The results showed that the PLI increases as a power function of the flow rate independent of the type of CVC. This study evidenced that the higher the blood flow rate used in the catheter, the greater the potential for thrombus formation. The PLI computed at the catheter outlet presented higher values when compared to the values computed at the vein outlet indicating that the blood flow through the CVC arterial lumen presents a proportionally larger thrombogenic potential when compared to the blood flow that leaves the vein towards the atrium. This finding may have consequences for clinical practice, since there is no specific flow value recommended in the catheter when the hemodialysis machine is turned on, and with this equation it was possible to demonstrate the thrombogenic potential that the flow rate can possibly offer.

Assuntos

RESUMO

The central venous catheter that is inserted in patients undergoing hemodialysis can cause hemodynamic instability and trigger complications such as thrombus formation. The objective of this study was to investigate hemostatic and numerical influences on thrombus formation in patients undergoing hemodialysis with a central venous catheter. Participants were assigned to three groups: I: clinical and laboratorial healthy individuals matched by sex and age (controls); II: participants after one month of insertion of the catheter and III: participants after 4 months of insertion of the catheter. Platelet activation was investigated by GPIIb/IIIa and p-selectin expressions using flow cytometry. A three-dimensional model of the catheter was constructed in the numerical simulation for the calculation of partial differential equation of a platelet activation model. A significant difference was detected by the expression of p-selectin comparing the group I (33.42 ± 4.74), group II (40.79 ± 5.54) and group III(51.00 ± 7.21) (p < 0.0001). The median values for GPIIb/IIIa were 10426 (10029-10721), 13921 (13412-15652) and 19946 (18714-21815) after catheter insertion (p < 0.0001), for groups I, II and III, respectively. Excluding the first arterial orifice, venous orifices tend to have greater platelet activation when compared to the other arterial orifices. The results of this study showed the influence of arterial and venous lateral orifices in stimulating the development of thrombi associated with the activation of platelet markers the longer the catheter was used.

Assuntos

RESUMO

BACKGROUND: The aim was to analyze the fracture resistance of human teeth treated endodontically and restored with posts made of bovine dentin, human dentin, or glass fiber, and to evaluate the fracture pattern. METHODS: Cylindrical posts of 1.5 mm in diameter cemented to the roots of human maxillary canines presented a length of 15 mm, cervical diameter of 5-5.5 mm in the mesiodistal direction, and 7-7.5 mm in the vestibule-palatal direction. The groups studied were: Group I-10 glass fiber posts; Group II-10 human dentin posts; Group III-10 bovine dentin posts (self-adhesive resin cement); and Group IV-10 bovine dentin posts (resin-modified glass-ionomer cements). The coronal part of tooth was restored with a standardized core build-up using composite. All of the groups were submitted to a compression force test and the resistance to fracture was verified using a universal testing machine. The fracture pattern was likewise evaluated. RESULTS: The values of resistance to fracture were: 723.3N in group I, 561.5N in group II, 556.6N in group III, and, 613.27N in group IV. However, no statistically significant difference was observed among the groups. The fractures in groups I and II were most commonly found in the middle/apical third and were considered irreparable. For restored teeth in group III, half of the fractures appeared in the cervical third and were reparable. In group IV, all of the fractures were reparable, with the majority in the cervical thirds. CONCLUSION: Bovine dentin can be used as intraradicular post to substitute human dentin and glass fiber posts. The greater the malleability of the post, the greater the chances of survival of the teeth when subjected to fracture testing.

Assuntos