RESUMO
OBJECTIVES: This study evaluated different designs of the conical implant-abutment connection (IAC) and their resistance to microgap formation under oblique loads as specified by the ISO standard for testing dental implants. Also evaluated was the effect of deviations from the ISO specifications on the outcomes. METHODS: Finite element analysis was conducted to compare the microgap formation and stress distribution among three conical IAC designs (A, B, and C) in two loading configurations: one compliant with ISO 14801 and one with a modified load adaptor (non-ISO). The different IAC designs varied in the taper, diameter, and cone height. The cone angle mismatch (Cam) between the implant and abutment was considered. A torque of 20 Ncm and oblique loads (up to 400 N) were simulated. RESULTS: The stresses produced by the screw-tightening torque varied among the different IAC designs. The contact height was approximately 0.3 mm for Designs A and B, and less than 0.03 mm for Design C. Under oblique loads, Design A maintained IAC sealing without gap formation up to 400 N. With the ISO adaptor, gaps appeared in Design B at 300 N and in Design C at 90 N. The non-ISO adaptor resulted in gap formation at 160 N for Design B and at 50 N for Design C. CONCLUSIONS: The IAC design and cone angle mismatch significantly influenced microgap formation, with some designs showing zero gaps even when the oblique load reached 400 N. The non-ISO adaptor increased gap formation in IACs B and C.
Assuntos
Projeto do Implante Dentário-Pivô , Análise do Estresse Dentário , Análise de Elementos Finitos , Humanos , Torque , Dente Suporte , Implantes Dentários , Estresse MecânicoRESUMO
BACKGROUND AND PURPOSE: Children with myopathies often experience muscle weakness in their lower limbs. However, the upper limbs are also affected and, at the same time, play a key role in daily living activities as well as in transfers and assisted mobility using auxiliary devices. The objective was to assess the performance of the elbow flexor and extensor muscles through static and dynamic contractions in children with myopathies and in their typical peers. METHODS: This was a case-control study. Seven children with different myopathies participated and were matched with typical children by sex and age (1:2). The muscle performance of elbow flexors (EFL) and elbow extensors (EEX) was assessed using an isokinetic dynamometer using isometric and isokinetic contractions at a speed of 120°s-1. The analyzed variables were peak torque (PT), total work (W), power (P), time to peak torque (TPT), acceleration time (AT), and deceleration time (DT). The raw variables were compared between groups using linear regression with mixed effects. A significance level of p < 0.05 was adopted. RESULTS AND DISCUSSION: Children with myopathies showed significantly lower values of PT, W, and P for both elbow muscle groups (p < 0.05) compared to typically developing children; TPT showed no difference between groups; and AT and DT were higher in children with myopathies than in typical ones (p < 0.05). Children with myopathies exhibited deficits in muscle performance, suggesting that the elbow muscles adopt atypical motor strategies, indicating impaired neuromuscular control. The isokinetic dynamometer is a device that can provide relevant information about muscle performance in this group of diseases.
Assuntos
Força Muscular , Músculo Esquelético , Humanos , Estudos de Casos e Controles , Criança , Masculino , Feminino , Músculo Esquelético/fisiopatologia , Músculo Esquelético/fisiologia , Força Muscular/fisiologia , Doenças Musculares/fisiopatologia , Torque , Dinamômetro de Força Muscular , Cotovelo/fisiopatologia , Adolescente , Articulação do Cotovelo/fisiopatologia , Articulação do Cotovelo/fisiologia , Contração Isométrica/fisiologia , Contração Muscular/fisiologiaRESUMO
INTRODUCTION: Implantology has become a primary solution for tooth loss due to excellent osseointegration and high long-term success rates. However, complications such as abutment screw loosening, especially in implant-supported single crowns, compromise prosthesis longevity. Anaerobic adhesives (AAs) have shown promise in mechanical fields for preventing screw loosening, but their effectiveness in dental implants, particularly zirconia, remains uncertain. This study evaluates the effect of medium-strength AA on the counter-torque and screw stability of zirconia implant abutments. METHODS: Twenty neodent Zi zirconia implants were divided into two groups: control (n = 10) without adhesive and experimental (n = 10) using medium-strength AA (Loctite 242) on the prosthetic screw. Abutment screws were torqued to 32 Ncm and underwent mechanical cycling simulating mastication. Counter-torque was measured post-cycling. Structural damage and adhesive residues were inspected using a stereomicroscope. Data were analyzed using descriptive statistics including means and standard deviations (SDs). The Shapiro-Wilk test was performed to assess data normality. The counter-torque values after cycling were compared to the installation torque value using the one-sample t-test. Comparison between groups was performed using Student's t test. Statistical significance was established as p < 0.05. RESULTS: The presence of AA was detected on all screws, without causing damage and was easily removable. Both groups showed significantly lower counter-torque values than the installation torque, with no significant intergroup difference. CONCLUSION: Medium-strength AA did not significantly affect the counter-torque values of zirconia implant abutment screws, although it was easily removable and caused no damage.
Assuntos
Dente Suporte , Torque , Zircônio , Zircônio/química , Técnicas In Vitro , Humanos , Cimentos Dentários/química , Projeto do Implante Dentário-Pivô , Análise do Estresse Dentário , Teste de Materiais , Implantes Dentários , Parafusos ÓsseosRESUMO
AIM: Insertion of dental implants causes bone deformation and induces residual bone compression stress, which can lead to implant failure if the bone loss threshold is exceeded. The current literature about bone stress is restricted to computer simulations and implant primary stability measurements after installation. This work measures the torque and deformation during implant insertion testing. PURPOSE: The aim of this work was to analyze the influence surface treatment, thread profile, body shape and the presence of microthreads in the neck on the primary stability, bone deformation and residual stress during dental implants insertion. The insertion torque and resonance frequency analysis (RFA) are the main technique used to measure the primary stability of dental implants. MATERIAL AND METHODS: Five models of dental implants with different surface treatments (machined and acid etching), thread profiles (triangular and trapezoidal) and body shapes (cylindrical and conical) were inserted in synthetic bone blocks (polyurethane) with a density of 30 PCF (0.48 g/cm³) compatible with the D2 bone. The insertion torque was quantified by a digital torque driver. Strain gauge extensometry technique was used to measure bone deformation during implant insertion. RESULTS: The bone deformation and torque increase as the number of implants turns insertion increases. Dental implant with trapezoidal thread profile needs higher insertion torque than triangular threads. Implants with a conical shape require higher insertion torque than cylindrical ones. The bone stress induced by machined implant insertion exceeded the bone's mechanical resistance, causing cracks. Conical implants showed better performance than cylindrical ones. The implants with a trapezoidal thread and those with a conical body induce greater insertion torque. CONCLUSION: Comparing the mechanical behavior, it was found that the machined implants had the worst performance in terms of stress distribution in the synthetic bone, resulting in cracks in the specimen during insertion. Implants with trapezoidal threads and those with a conical body induce insertion torque and bone compression stresses that do not harm osseointegration. CLINICAL RELEVANCE: Excessive deformations in the peri-implant bone led to bone necrosis and implant failure. Thus, the surgeons must analyze the influence of surface treatment, thread profile, and body shape on the osseointegration process.
Assuntos
Implantes Dentários , Torque , Humanos , Propriedades de Superfície , Análise do Estresse Dentário , Planejamento de Prótese Dentária , Implantação Dentária Endóssea , Estresse Mecânico , Análise de Frequência de RessonânciaRESUMO
INTRODUCTION: Postural control involves the coordination of muscle synergies of lower limb for the performance of postural strategies. However, the relationship between muscle function and postural control of older adults with different levels of physical activity has not yet been fully elucidated. The aim of this study was to analyze the influence of muscle function of lower limb on postural control in tasks with disturbance in the visual and somatosensory systems of older adults with different levels of physical activity. METHODS: 61 older adults participated in this study. The assessment of postural control was performed using posturography in tasks with visual and somatosensory systems disturbance. To assess peak torque and mean power of the lower limb, an isokinetic dynamometer was used. A regression test was performed to investigate the association between muscle function and posture. The regression model was adjusted for the level of physical activity. RESULTS: The complexity of the task and level of physical activity influenced the association between muscle function and postural control. The conditions that involved simultaneous disturbance in the visual and somatosensory systems were the ones that showed the greatest combination of associations, regardless of the stance type. CONCLUSION: The ability to produce ankle and hip muscle power seems to be crucial for the postural control of the older adults in tasks that involve reducing the base of support associated with disturbances in the visual and somatosensory system. Physical activity programs for older adults should include strength and power training for the ankle, knee, and hip muscles, with emphasis on hip abductors.
Assuntos
Exercício Físico , Força Muscular , Músculo Esquelético , Equilíbrio Postural , Humanos , Idoso , Equilíbrio Postural/fisiologia , Masculino , Feminino , Músculo Esquelético/fisiologia , Exercício Físico/fisiologia , Força Muscular/fisiologia , Extremidade Inferior/fisiologia , Postura/fisiologia , Torque , Idoso de 80 Anos ou mais , Pessoa de Meia-IdadeRESUMO
BACKGROUND: The Aussie Current (AC) is a medium frequency electrical current of 1 and 4 kHz modulated in bursts used to reduce pain, increase muscle strength and produce torque in adults. However, there is still no consensus on these effects. OBJECTIVES: To systematically review available evidence on the effects of AC on pain, muscle strength, torque, comfort and functionality in adults. METHODS: This systematic review was conducted according to PRISMA guidelines and registered in PROSPERO. A search was carried out in the Lilacs, Scielo, Web of Science, Scopus, Pubmed and PEDro databases, from 10/2021 to 02/2022. Randomized or non-randomized clinical trials that investigated the effects of the application of AC were selected. Two reviewers independently assessed the risk of bias in the studies using the JADAD scale. The quality of the evidence of some outcomes was assessed using the GRADE system of rating The selected studies used AC as intervention and presented pain, muscle strength, torque, comfort and/or functionality as outcomes. RESULTS: 21 studies (590 participants) were included. 14 articles were classified as low quality and 7 as high quality. The quality of the evidence was moderate. The effects of AC on the studied outcomes are still controversial. As for the consensus regarding the chosen frequency, 80,9% (n = 17) of the studies used the frequency of 1 kHz. CONCLUSION: Although it was verified that the frequency of 1 kHz is the most used, the studies that address AC are scarce and with methodological diversity, which makes it difficult to assess the effectiveness of this current. Thus, we suggest that further studies should be carried out to elucidate the effects of AC on pain, muscle strength and torque production.
Assuntos
Força Muscular , Torque , Humanos , Força Muscular/fisiologia , Terapia por Estimulação Elétrica/métodos , Manejo da Dor/métodosRESUMO
BACKGROUND: The rate of torque development (RTD) has been associated with sports performance and can be improved during the biological maturation process of young soccer players. The aim of this study was to compare the effects of maturity status on the knee extensors' RTD of soccer players after appropriate normalization. METHODS: Twenty-seven young male soccer players aged 13-18 years old were allocated into two groups: pubescent (PUB, n = 11) and postpubescent (POSP, n = 16). RTD was obtained by performing a maximum voluntary isometric contraction at six different knee joint angles (30º, 45º, 60º, 75º, 90º, and 105º). Anthropometric (height and body mass) and muscle architecture variables (muscle thickness, muscle volume, fascicle length, pennation angle, and cross-section area) were evaluated as body size descriptors and used to identify the best way for appropriate normalization of RTD data. RESULTS: Muscle architecture variables showed no correlations with RTD (p > 0.05), while body mass showed a positive correlation (0.405 < r < 0.680; p < 0.05). Maturity status showed positive effects on absolute late RTD values (N·m·s-1) obtained at four different angles (60º, 75º, 90º, and 105º). However, maturity status showed no effects on RTD values after normalization by body mass (N·m·s-1·kg-1). CONCLUSIONS: Maturity status showed no positive effects on RTD values after appropriate normalization by body mass in young soccer players.
Assuntos
Contração Isométrica , Futebol , Torque , Humanos , Futebol/fisiologia , Masculino , Adolescente , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/crescimento & desenvolvimento , Músculo Esquelético/fisiologia , Força Muscular/fisiologia , Articulação do Joelho/anatomia & histologia , Articulação do Joelho/fisiologia , Desempenho Atlético/fisiologiaRESUMO
OBJECTIVES: To evaluate whether the application of an anaerobic adhesive (AA) to the abutment screws interferes with the implant stability quotient (ISQ) values in abutments with external hexagon (EHC) and conical connections (CC). MATERIALS AND METHODS: 20 implants 4.0 mm x 10 mm were used, with similar formats, 10 with EHC and 10 with CC, inserted by the same operator into fresh bovine ribs. The abutment was then screwed with a high precision digital torque meter, and resonance frequency was measured. The abutments were then unscrewed, a drop of Loctite 242 adhesive was applied along the entire length of the thread, the abutments were screwed again (Groups EHC-AA and CC-AA). The ISQ was registered immediately, 24 h, and 72 h after installation. Data were analyzed using descriptive statistics and comparison tests (p < 0.05). RESULTS: ISQ values measured in abutments without AA were significantly higher than those measured after applying the adhesive, for EHC and CC. The one-way repeated measures ANOVA showed that, in the intragroup analysis, there was no statistically significant difference in the ISQ, comparing the three measurement moments after applying the adhesive, irrespective of connection system (CC: F = 0.191, p = 0.827; EHC: F = 0.323, p = 727), which suggests that the adhesive curing does not affect the ISQ. CONCLUSIONS: The use of an AA on abutment screws had a significant effect on RFA measurements, for EHC and CC. The curing time of the AA did not affect the ISQ values measured in the abutments. CLINICAL RELEVANCE: The ISQ values cannot be compared in situations with and without AA.
Assuntos
Dente Suporte , Animais , Bovinos , Análise de Frequência de Ressonância , Projeto do Implante Dentário-Pivô , Torque , Cimentos Dentários/química , Retenção em Prótese Dentária , Teste de Materiais , Implantes Dentários , Técnicas In VitroRESUMO
Kilohertz-frequency alternating currents (KFACs) have been indicated to minimize muscle atrophy and weakness. However, the optimal stimulation parameters still need to be determined. OBJECTIVE: This study aimed to investigate the effects of different KFACs on evoked torque, current efficiency, and perceived discomfort. DESIGN: KFACs with frequencies of 1 kHz (Aussie current) and 2.5 kHz (Russian current), along with two duty cycles (10% and 20%), were randomly applied to the triceps surae muscle of healthy participants using a crossover design. The NMES intensity, NMES-evoked torque, NMES efficiency, and NMES discomfort were measured in maximal and submaximal conditions. Statistical analyses were conducted using a two-way mixed-model ANOVA with repeated measures. Forty-four participants were included. RESULTS: Aussie currents produced higher evoked torque and efficiency in maximal and submaximal efforts, with higher perceived discomfort in maximal effort. Although the Australian current may cause greater discomfort at maximal efforts, it matches the Russian current in perceived discomfort at submaximal levels. The 20% duty cycle produced the highest efficiency in submaximal efforts. CONCLUSION: In both maximal and submaximal efforts, the Aussie current demonstrated superior NMES efficiency, yielding higher torque with lower amplitude than the Russian current. Clinicians should take these findings into consideration when prescribing KFACs to optimize clinical outcomes.
Assuntos
Estudos Cross-Over , Músculo Esquelético , Torque , Humanos , Masculino , Músculo Esquelético/fisiologia , Adulto , Feminino , Adulto Jovem , Contração Muscular/fisiologiaRESUMO
CONTEXT: The evaluation of quadriceps muscle inhibition with the interpolated twitch technique is usually performed by stimulating the femoral nerve (FN). However, there are some problems related to the use of this stimulation site, which may be partially overcome by delivering the stimulation over the motor point (MP). This study sought to compare MP to FN stimulation at different joint angles for the evaluation of quadriceps muscle inhibition, resting peak torque, and discomfort in healthy women. DESIGN: Cross-sectional study. METHODS: Sixteen healthy women (age: 28 [4] y; body mass: 60 [5] kg; height: 162 [5] cm) participated in this study. Supramaximal paired stimuli were delivered to the FN and to the rectus femoris MP before and during maximal voluntary contractions at different knee angles (15°, 30°, 45°, 60°, and 90° of knee flexion) to assess muscle inhibition and resting peak torque. Discomfort was also recorded for each stimulation site and knee angle. RESULTS: Muscle inhibition was similar between the 2 stimulation sites (P > .05) and was higher at 45° than at 90° (P = .03). MP stimulation evoked lower resting peak torque at 30° (P = .004), 60° (P = .006), and 90° (P = .006) and higher discomfort at 30° (P = .008) and 90° (P = .027) compared to FN stimulation. CONCLUSIONS: Despite lower resting peak torque and higher discomfort at some angles, MP stimulation provided similar muscle inhibition to FN stimulation at all knee angles and is therefore a valid method to evaluate quadriceps muscle inhibition in healthy women. MP stimulation can be used as an alternative to FN stimulation for the evaluation of quadriceps muscle inhibition with no added discomfort at the angles where muscle inhibition is the highest.
Assuntos
Nervo Femoral , Músculo Quadríceps , Torque , Humanos , Feminino , Músculo Quadríceps/fisiologia , Adulto , Nervo Femoral/fisiologia , Estudos Transversais , Estimulação Elétrica/métodos , Adulto Jovem , Contração Muscular/fisiologia , Articulação do Joelho/fisiologia , Voluntários SaudáveisRESUMO
STATEMENT OF PROBLEM: The biomechanical stability of the implant-prosthesis assembly and its maintenance under function is a determining factor in the success of implant prosthesis rehabilitation, but studies of different angular tapers are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the axial displacement and torque loss of prosthetic abutments with Morse-type connections of different angular tapers after thermomechanical cycling by using microcomputed tomography (µCT) and a digital torque wrench. MATERIAL AND METHODS: Eighteen Ø3.5×11.5-mm implants were embedded in polyvinyl chloride cylinders, and the 3 different types of abutments (n=6) with angular tapers of 11.5 degrees - Alvim Cone Morse (ACM-11.5), 16.0 degrees - Helix Gran Morse (HGM-16), and 24.0 degrees - Nobel Replace Conical Connection (NRC-24) were installed with the torque recommended by the manufacturers. To calculate the axial displacements of the abutments about the implants, zirconia maxillary canine crowns were fabricated using a computer-aided design and computer-aided manufacturing (CAD-CAM) system and cemented onto the abutments. Before and after thermomechanical cycling, the assemblies were scanned using microtomography (micro-CT) to assess axial displacement, and the torque losses were calculated after the abutments were finally unscrewed. A load of 100 N, frequency of 2 Hz, and 106 cycles with temperature variation of 5 °C to 55 °C were used for the thermomechanical cycling. Analysis of variance and the Tukey post hoc test (α=.05) were used for analysis. RESULTS: A significant difference was observed between the abutments for axial displacement, measured after thermomechanical cycling (P=.002). The ACM-11.5 abutment showed the highest mean value (134.1 ±58.7 µm), different from HGM-16 (63.3 ±26.1 µm) (P=.013) and NRC-24 (42.7 ±8.7 µm) (P=.002); the 2 latter groups were similar to each other (P=.618). For the torque losses, no significant difference was found among the abutments (P=.928), but there were significant differences for the thermomechanical cycling (before and after) (P<.001) in that the loss of torque was greater after thermocycling. CONCLUSIONS: The smaller the taper angle of the Morse-type prosthetic abutment, the greater its axial displacement, and the thermomechanical cycling significantly reduced pretorque, regardless of taper.
Assuntos
Dente Suporte , Projeto do Implante Dentário-Pivô , Torque , Análise do Estresse Dentário , Implantes Dentários , Humanos , Microtomografia por Raio-X , Técnicas In Vitro , Desenho Assistido por Computador , Zircônio , CoroasRESUMO
BACKGROUND: To verify the influence of macrogeometry with healing chambers on the osseointegration of dental implants by analyzing implant stability quotient (ISQ) and evaluate the correlation between insertion torque and ISQ insertion with different macrogeometries. METHODS: In total, 26 implants were installed in the posterior mandible of eight patients with sufficient bone height for the installation of implants measuring 3.5 mm in diameter and 9.0 mm in length. The implants were categorized according to two types of macrogeometry: a test group (GT) with 13 conical implants with healing chambers and a control group (GC) with 13 conical implants with conventional threads. To insert the implants, a bone drilling protocol was used up to a diameter of 3 mm with the last helical bur. The insertion torque of the implants was evaluated, followed by the measurement of ISQ at 0 (T-0), 7 (T-7), 14 (T-14), 21 (T-21), 28 (T-28), and 42 (T-42) days. RESULTS: The mean insertion torque was 43 Ncm in both groups, without a significant difference. Moreover, no significant difference in the ISQ values was found between the groups at different time points (p > 0.05), except at T-7 (GT = 69.87±1.89 and GC = 66.48±4.49; p = 0.01). Although there was no significant difference, ISQ median values were higher in the GT group than GC group at 28 days (GT = 67.98 and GC = 63.46; p = 0.05) and 42 days (GT = 66.12 and GC = 60.33; p = 0.09). No correlation was found between the insertion torque and ISQ insertion (p > 0.05). CONCLUSION: Furthermore, implants with a 3.5 mm diameter macrogeometry, with or without healing chambers, inserted with a drilling protocol up to 3 mm in diameter of the last helical bur, led to a similar secondary stability, with no difference in ISQ values. Although, implants with healing chamber demonstrates ascending values in the graph of ISQ, having a trend of faster osseointegration than implants without healing chambers. Both macrogeometries provide a similar primary stability to implants. TRIAL REGISTRATION: This study was registered retrospectively in ReBec (brazilian registry of clinical trials) under the number RBR-96n5×69, on the date of 19/06/2023.
Assuntos
Implantação Dentária Endóssea , Implantes Dentários , Mandíbula , Osseointegração , Torque , Humanos , Osseointegração/fisiologia , Implantação Dentária Endóssea/métodos , Masculino , Feminino , Pessoa de Meia-Idade , Mandíbula/cirurgia , Planejamento de Prótese Dentária , Adulto , Cicatrização , Idoso , Retenção em Prótese Dentária , Propriedades de SuperfícieRESUMO
OBJECTIVES: This study aimed to investigate the osseointegration of titanium (Ti) implants with micro-nano textured surfaces functionalized with strontium additions (Sr) in a pre-clinical rat tibia model. METHODOLOGY: Ti commercially pure (cp-Ti) implants were installed bilaterally in the tibia of 64 Holtzman rats, divided into four experimental groups (n=16/group): (1) Machined surface - control (C); (2) Micro-nano textured surface treatment (MN); (3) Micro-nano textured surface with Sr2+ addition (MNSr); and (4) Micro-nano textured surface with a higher complementary addition of Sr2+ (MNSr+). In total, two experimental euthanasia periods were assessed at 15 and 45 days (n=8/period). The tibia was subjected to micro-computed tomography (µ-CT), histomorphometry with the EXAKT system, removal torque (TR) testing, and gene expression analysis by PCR-Array of 84 osteogenic markers. Gene expression and protein production of bone markers were performed in an in vitro model with MC3T3-E1 cells. The surface characteristics of the implants were evaluated by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and laser scanning confocal microscopy. RESULTS: SEM, confocal, and EDS analyses demonstrated the formation of uniform micro-nano textured surfaces in the MN group and Sr addition in the MNSr and MNSr+ groups. TR test indicated greater osseointegration in the 45-day period for treated surfaces. Histological analysis highlighted the benefits of the treatments, especially in cortical bone, in which an increase in bone-implant contact was found in groups MN (15 days) and MNSr (45 days) compared to the control group. Gene expression analysis of osteogenic activity markers showed modulation of various osteogenesis-related genes. According to the in vitro model, RT-qPCR and ELISA demonstrated that the treatments favored gene expression and production of osteoblastic differentiation markers. CONCLUSIONS: Micro-nano textured surface and Sr addition can effectively improve and accelerate implant osseointegration and is, therefore, an attractive approach to modifying titanium implant surfaces with significant potential in clinical practice.
Assuntos
Implantes Dentários , Osseointegração , Estrôncio , Propriedades de Superfície , Tíbia , Titânio , Microtomografia por Raio-X , Titânio/química , Osseointegração/efeitos dos fármacos , Animais , Estrôncio/farmacologia , Estrôncio/química , Fatores de Tempo , Tíbia/efeitos dos fármacos , Tíbia/cirurgia , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Teste de Materiais , Masculino , Osteogênese/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Camundongos , Torque , Expressão Gênica/efeitos dos fármacos , Análise de Variância , Reação em Cadeia da Polimerase em Tempo Real , Ratos , Nanoestruturas , Valores de ReferênciaRESUMO
The measurement of isometric muscle torque with hand-held dynamometry is a technique little studied in the pediatric setting for the evaluation of maximal isometric muscle strength. OBJECTIVE: to determine the reliability of hand-held dynamometry to obtain the maximal isometric torque of upper and lower limb muscle groups in Chilean children and adolescents. PATIENTS AND METHODS: Crosssectional study. Seventy-two participants aged between 7 and 15 years were selected from a school in Talca. Maximal isometric torque was recorded in 15 muscle groups of upper and lower limbs through hand-held dynamometry. Intra- and inter-rater evaluation was used, applying the intraclass correlation coefficient (ICC) to determine the reliability of the tests and Bland-Altman plots to evaluate concordance. RESULTS: The results demonstrated good to excellent inter-rater reliability (ICC = 0.850.98) and intra-rater reliability (ICC = 0.87-0.98). Only two groups, hip extensors and abductors, showed good inter-rater reliability (ICC = 0.85 and ICC = 0.88, respectively); and one group, the ankle dorsiflexors, showed good intra-rater reliability (ICC = 0.87). 100% of the tests presented at least 95.8% inter- and intra-rater agreement on the Bland-Altman plots. CONCLUSION: The evaluation of isometric muscle torque using hand-held dynamometry is a reliable procedure for use in different growth periods.
Assuntos
Contração Isométrica , Dinamômetro de Força Muscular , Força Muscular , Torque , Humanos , Criança , Adolescente , Reprodutibilidade dos Testes , Masculino , Feminino , Estudos Transversais , Chile , Contração Isométrica/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Variações Dependentes do Observador , Extremidade Inferior/fisiologiaRESUMO
This study aimed to verify the relationship between changes in thigh muscle-localized bioelectrical impedance analysis (ML-BIA) parameters and performance in a multiple-set exercise. The sample consisted of 30 female university students (22.1 ± 3.2 years). The ML-BIA parameters, including localized muscle resistance (ML-R), reactance (ML-Xc), and phase angle (ML-AngF), were evaluated using a tetrapolar bioelectric impedance device operating at a frequency of 50 KHz. The multiple sets protocol was performed with an isokinetic dynamometer. For body composition, total and leg lean soft tissue (LST) were evaluated using dual X-ray absortiometry. Student's t-test for paired samples was used to compare the ML-BIA parameters and thigh circumference pre and postexercise. Linear regression analysis was performed to verify the ∆ML-PhA as a predictor of peak torque for the three sets alone while controlling for total and leg LST. There were differences in the ML-R (∆ = 0.02 ± 1.45 Ω; p = 0.001; and E.S = 0.19), ML-Xc (∆ = 2.90 ± 4.12 Ω; p = 0.043; and E.S = 0.36), and thigh circumference (∆ = 0.82 ± 0.60 cm; p < 0.001; and E.S = 0.16) pre- and post-multiple sets. ΔML-PhA was a predictor of performance in the first set (p = 0.002), regardless of total and leg LST. However, the ΔML-PhA lost its explanatory power in the other sets (second and third), and the variables that best explained performance were total and leg LST. The ML-BIA (ML-R and ML-Xc) parameters were sensitive and changed after the multiple sets protocol, and the ΔML-PhA was a predictor of performance in the first set regardless of the total and leg LST.
Assuntos
Composição Corporal , Impedância Elétrica , Dinamômetro de Força Muscular , Músculo Esquelético , Humanos , Feminino , Adulto Jovem , Composição Corporal/fisiologia , Músculo Esquelético/fisiologia , Adulto , Coxa da Perna/fisiologia , Torque , Força Muscular/fisiologia , Exercício Físico/fisiologia , Desempenho Atlético/fisiologiaRESUMO
We tested if the movement slowness of individuals with Parkinson's disease is related to their decreased ability to generate adequate net torques and linearly coordinate them between joints. This cross-sectional study included ten individuals with Parkinson's disease and ten healthy individuals. They performed planar movements with a reversal over three target distances. We calculated joint kinematics of the elbow and shoulder using spatial orientation. The muscle, interaction, and net torques were integrated into the acceleration/deceleration phases of the fingertip speed. We calculated the linear correlations of those torques between joints. Both groups modulated the elbow and shoulder net torques with target distances. They linearly coupled the production of torques. Both groups did not modulate the interaction torques. The movement slowness in Parkinson's disease was related to the difficulty in generating the appropriate muscle and net torques in the task. The interaction torques do not seem to play any role in movement control.
Assuntos
Articulação do Cotovelo , Atividade Motora , Doença de Parkinson , Articulação do Ombro , Fenômenos Biomecânicos , Doença de Parkinson/fisiopatologia , Articulação do Cotovelo/fisiopatologia , Articulação do Ombro/fisiopatologia , Músculo Esquelético/fisiopatologia , Torque , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , IdosoRESUMO
The objective of this study was to analyze the influence of insertion torque, bone type, and peri-implant bone loss on implant stability quotient (ISQ) of cylindrical external hexagon (EH) and Morse Taper (MT) implants. Forty-four single implants were placed in the edentulous areas of 20 patients who met the inclusion and exclusion criteria. Immediately after implant placement (t1) and after osseointegration (four and six months for mandible and maxilla, respectively) (t2), insertion torque, resonance frequency, and peri-implant bone loss were measured using probing depths and digital periapical radiography. A significant difference was noted in the ISQ values between t1 and t2 in type III bone for EH and MT implants. No significant difference in bone loss values was observed when comparing bone types for EH or MT in all evaluated sites. Based on marginal bone loss assessed using radiography, there was no significant difference between the MT and EH groups. A positive correlation between torque and ISQ t1 value was observed for MT (correlation: 0.439; p = 0.041) and EH (correlation: 0.461; p = 0.031) implants. For EH and MT implants, the greater the insertion torque, the greater was the ISQ value (moderately positive correlation). A weak negative correlation was found between bone type and ISQ t1 for MT implants. Contrarily, no correlation was observed between bone type and ISQ t1 for EH implants. In all cases, bone loss around the implants was clinically normal.
Assuntos
Perda do Osso Alveolar , Implantação Dentária Endóssea , Osseointegração , Torque , Humanos , Masculino , Feminino , Perda do Osso Alveolar/diagnóstico por imagem , Osseointegração/fisiologia , Implantação Dentária Endóssea/métodos , Pessoa de Meia-Idade , Valores de Referência , Fatores de Tempo , Resultado do Tratamento , Estatísticas não Paramétricas , Planejamento de Prótese Dentária , Adulto , Mandíbula/cirurgia , Mandíbula/diagnóstico por imagem , Retenção em Prótese Dentária/métodos , Idoso , Análise de Frequência de Ressonância , Implantes Dentários , Maxila/cirurgia , Maxila/diagnóstico por imagem , Implantes Dentários para Um Único Dente , Reprodutibilidade dos TestesRESUMO
OBJECTIVES: To evaluate structural damage and loosening of abutments placed on narrow diameter implants after cyclic fatigue. METHODS: Sixty Morse taper narrow diameter implants (Neodent, Brazil) received two types of abutments (1PA- one-piece abutment or 2PA- two-piece abutment), which were randomly divided into 3 fatigue experiments (n = 10). The implants were placed into a customized supporting holder and a software-assisted digital torque wrench secured the manufacturer recommended torque for each abutment. Cone beam computed tomography (CBCT) scans were acquired, before and after fatigue, and post-processed (software e-Vol DX) to assess damage and abutment displacement. The boundary fatigue method was adapted to use 2 × 106 cycles, 2 Hz of frequency and constant peak load of 80 N (first experiment) that varied according to the failure rate of previous specimens (second and third experiments). Failure was evaluated using CBCT scans and removal torque values. Data were used to estimate long-term torque degradation, probability of failure and Weibull modulus (software ALTA PRO9). RESULTS: All 2PA specimens became loosen independently of the applied fatigue load, and structural bending was observed in 14 abutments. Eight 1PA got loosen during the fatigue experiment. The Weibull analysis showed a lower modulus (m = 1.0; 0.7, 1.4) for 1PA than for 2PA (m = 2.6; 2, 3.4) resulting in longer predicted lifetimes and slower torque degradation for 1PA than for 2PA specimens. SIGNIFICANCE: 1PA showed greater long-term survival probability than 2PA. Predicting the lifetime and mechanical behavior of implant-abutment systems are useful information to clinicians during the decision-making process of oral rehabilitations.
Assuntos
Tomografia Computadorizada de Feixe Cônico , Dente Suporte , Projeto do Implante Dentário-Pivô , Falha de Restauração Dentária , Análise do Estresse Dentário , Torque , Implantes Dentários , Teste de MateriaisRESUMO
The aims of the present study were to: i) analyse the between-session reliability of dry-land and in-water swimming tests, and ii) investigate the prevalence of meaningful asymmetries in swimming athletes. Twenty-eight swimmers (21 males, 7 females) performed anthropometric, shoulder range of motion (ROM), countermovement jump, shoulder isokinetic torque, and 15-s tethered swimming tests two times, 1 week apart. Inter-limb asymmetries were calculated for each variable. Raw data reliability was determined using the intraclass coefficient correlation (ICC) and the typical error of measurement (TEM), and effect size (ES) was used to determine systematic bias between test sessions. At an individual level, inter-limb asymmetries were compared to the coefficient of variation (CV) to determine whether they were real. The between-session reliability was good to excellent (0.75 to 1.00) for most of the raw data, except for ROM. Between-session ES was predominately "trivial" or "small" for raw data and asymmetries, reinforcing that the values did not change significantly between the sessions. In addition, real asymmetries were seen in some tested metrics, depending on the test. In conclusion, the tested variables presented good levels of between-session reliability and were able to detect real and consistent asymmetries.
Assuntos
Teste de Esforço , Amplitude de Movimento Articular , Natação , Humanos , Natação/fisiologia , Masculino , Reprodutibilidade dos Testes , Feminino , Adolescente , Amplitude de Movimento Articular/fisiologia , Teste de Esforço/métodos , Adulto Jovem , Torque , Antropometria , Ombro/fisiologiaRESUMO
Neuromuscular electrical stimulation (NMES) can improve physical function in different populations. NMES-related outcomes may be influenced by muscle length (i.e., joint angle), a modulator of the force generation capacity of muscle fibers. Nevertheless, to date, there is no comprehensive synthesis of the available scientific evidence regarding the optimal joint angle for maximizing the effectiveness of NMES. We performed a systematic review to investigate the effect of muscle length on NMES-induced torque, discomfort, contraction fatigue, and strength training adaptations in healthy and clinical adult populations (PROSPERO: CRD42022332965). We conducted searches across seven electronic databases: PUBMED, Web of Science, EMBASE, PEDro, BIREME, SCIELO, and Cochrane, over the period from June 2022 to October 2023, without restricting the publication year. We included cross-sectional and longitudinal studies that used NMES as an intervention or assessment tool for comparing muscle lengths in adult populations. We excluded studies on vocalization, respiratory, or pelvic floor muscles. Data extraction was performed via a standardized form to gather information on participants, interventions, and outcomes. Risk of bias was assessed using the Revised Cochrane risk-of-bias tool for cross-over trials and the Physiotherapy Evidence Database scale. Out of the 1185 articles retrieved through our search strategy, we included 36 studies in our analysis, that included 448 healthy young participants (age: 19-40 years) in order to investigate maximum evoked torque (n = 268), contraction fatigability (n = 87), discomfort (n = 82), and muscle strengthening (n = 22), as well as six participants with spinal cord injuries, and 15 healthy older participants. Meta-analyses were possible for comparing maximal evoked torque according to quadriceps muscle length through knee joint angle. At optimal muscle length 50° - 70° of knee flexion, where 0° is full extension), there was greater evoked torque during nerve stimulation compared to very short (0 - 30°) (p<0.001, CI 95%: -2.03, -1.15 for muscle belly stimulation, and -3.54, -1.16 for femoral nerve stimulation), short (31° - 49°) (p = 0.007, CI 95%: -1.58, -0.25), and long (71° - 90°) (p<0.001, CI 95%: 0.29, 1.02) muscle lengths. At long muscle lengths, NMES evoked greater torque than very short (p<0.001, CI 95%: -2.50, -0.67) and short (p = 0.04, CI 95%: -2.22, -0.06) lengths. The shortest quadriceps length generated the highest perceived discomfort for a given current amplitude. The amount of contraction fatigability was greater when muscle length allowed greater torque generation in the pre-fatigue condition. Strength gains were greater for a protocol at the optimal muscle length than for short muscle length. The quality of evidence was very high for most comparisons for evoked torque. However, further studies are necessary to achieve certainty for the other outcomes. Optimal muscle length should be considered the primary choice during NMES interventions, as it promotes higher levels of force production and may facilitate the preservation/gain in muscle force and mass, with reduced discomfort. However, a longer than optimal muscle length may also be used, due to possible muscle lengthening at high evoked tension. Thorough understanding of these physiological principles is imperative for the appropriate prescription of NMES for healthy and clinical populations.