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61.
《Dental materials》2022,38(1):204-213
ObjectiveTo investigate the fatigue behavior of restored teeth, in particular the mechanisms of longitudinal dentinal cracking under cyclic mechanical loading, using finite element analysis (FEA) and the stress-life (S-N) approach.MethodsTen root-filled premolars restored with resin composites were subjected to step-stress cyclic loading to produce longitudinal cracks. Fracture loads and number of cycles completed at each load level were recorded. FEA was used to predict the stress amplitude of each component under the global cyclic load. Both intact and debonded conditions were considered for the dentin-composite interface in the FEA. The predicted stress concentrations were compared with the fracture patterns to help elucidate the failure mechanisms. The S-N approach was further used to predict the lifetimes of the different components in the restored teeth. Cumulative fatigue damage was represented by the sum of the fractions of life spent under the different stress amplitudes.ResultsLongitudinal cracks were seen in ~50% of the samples with a mean fracture load of 770 ± 45 N and a mean number of cycles to failure of 32,297 ± 12,624. The longitudinal dentinal cracks seemed to start near the line angle of the cavity, and propagated longitudinally towards the root. The sum of fractions of life spent for the dentin-composite interface exceeded 1 after ~7000 cycles when that for dentin was much lower than 1, indicating that interfacial debonding would occur prior to dentin fracture. This was supported by micro-CT images showing widened interfacial space in the cracked samples. In the debonded tooth, FEA showed dentinal stress concentrations at the gingival wall of the cavity, which coincided with the longitudinal cracks found in the cyclic loading test. The sum of fractions of life spent for dentin was close to 1 at ~30,000 cycles, similar to the experimental value.SignificanceDebonding of the dentin-composite interface may occur prior to longitudinal cracking of dentin in root-filled teeth under cyclic loading. The approximate time of occurrence for these events could be estimated using fatigue analysis with stresses provided by FEA. This methodology can therefore be used to evaluate the longevity of restoration designs for root-filled teeth. 相似文献
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ObjectiveThe aim of this study is to examine the effectiveness of foot reflexology and back massage on optimizing the sleep quality and reducing the fatigue of hemodialysis patients.MethodsThe study includes 105 volunteer patients who were registered at a private dialysis clinic and were receiving hemodialysis treatment. Foot reflexology and back massage were administered to the patients two times a week for four weeks. The Visual Analogue Scale for Fatigue and the Pittsburg Sleep Quality Index were used to collect data.ResultsThe differences between the pretest and posttest score averages of the patients on the Visual Analogue Scale for Fatigue and the Pittsburg Sleep Quality Index were statistically significant (p < 0.001).ConclusionFoot reflexology and back massage were shown to improve the sleep quality and reduce the fatigue of hemodialysis patients. Compared to back massage, foot reflexology was determined to be more effective. 相似文献
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《Journal of pain and symptom management》2020,59(6):1320-1343
ContextFatigue is a symptom reported by patients with a variety of chronic conditions. However, it is unclear whether fatigue is similar across conditions. Better understanding its nature could provide important clues regarding the mechanisms underlying fatigue and aid in developing more effective therapeutic interventions to decrease fatigue and improve quality of life.ObjectivesTo better understand the nature of fatigue, we performed a qualitative metasynthesis exploring patients' experiences of fatigue across five chronic noninfectious conditions: heart failure, multiple sclerosis, rheumatoid arthritis, chronic kidney disease, and chronic obstructive pulmonary disease.MethodsWe identified 34 qualitative studies written in the last 10 years describing fatigue in patients with one of the aforementioned conditions using three databases (Embase, PubMed, and CINAHL). Studies with patient quotes describing fatigue were synthesized, integrated, and interpreted.ResultsAcross conditions, patients consistently described fatigue as persistent overwhelming tiredness, severe lack of energy, and physical weakness that worsened over time. Four common themes emerged: running out of batteries, a bad life, associated symptoms (e.g., sleep disturbance, impaired cognition, and depression), and feeling misunderstood by others, with a fear of not being believed or being perceived negatively.ConclusionIn adults with heart failure, multiple sclerosis, rheumatoid arthritis, chronic kidney disease, and chronic obstructive pulmonary disease, we found that fatigue was characterized by severe energy depletion, which had negative impacts on patients' lives and caused associated symptoms that exacerbated fatigue. Yet, fatigue is commonly misunderstood and inadequately acknowledged. 相似文献
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Tuba Guler Yesim Garip Fulya Dortbas Yasemin Pekin Dogan 《The Egyptian Rheumatologist》2018,40(2):117-121
Aim of the work: To evaluate the quality of life (QoL) in Familial Mediterranean Fever (FMF) patients, and determine its association with fatigue, depression, disease severity and other clinical parameters. Patients and methods: Sixty FMF patients were included. QoL was assessed by Short Form-36 (SF-36), depression by Hamilton Depression Scale (HDS), and fatigue by Fatigue severity scale (FSS). Disease severity score and Mutations of the Mediterranean fever (MEFV) gene were assessed. Results: The mean age of patients was 33.73 ± 9.81 years and disease duration 14.6 ± 12.1 years. They were 35 females and 25 males. FMF patients scored significantly higher in FSS (29.9 ± 17.6) and HDS (15.1 ± 8.5) compared to the control (10.6 ± 7.1 and 6.3 ± 9.4; p < 0.0001 respectively) while all SF36 sub-items except mental health were significantly lower (p < 0.05). MEFV gene mutation was present in 49 (81.7%) patients. The visual analogue scale of pain significantly negatively correlated with the FSS (p < 0.0001), HDS (p < 0.0001) and all SF36 sub-items except mental health (p < 0.0001). Disease duration, age of onset, and duration of attacks showed no significant correlation with FSS, HDS and SF36. Delay in diagnosis significantly correlated with FSS (p < 0.0001) and negatively with SF36 sub-items physical role (p = 0.02), general health (p = 0.01) and social functioning (p = 0.03). Age of diagnosis significantly correlated with FSS (p = 0.03) and negatively with SF36-vitality (p = 0.047). There was a significant effect of disease severity on QoL, fatigue and depression (p < 0.05). Conclusion: QoL is associated with fatigue, depression and disease severity in FMF patients. It should be used in routine clinical evaluation as an outcome measure in FMF. 相似文献
66.
Mary C. Davis Morris A. Okun Denise Kruszewski Alex J. Zautra Howard Tennen 《The journal of pain》2010,11(12):1338-1347
Fatigue is a common, disabling symptom for individuals with rheumatoid arthritis (RA). This study 1) examined sex differences in the relations between daily changes in positive and negative interpersonal events and same-day and next-day fatigue and 2) tested positive affect and negative affect as mediators of the associations between changes in interpersonal events and fatigue. Reports of fatigue, number of positive and negative interpersonal events, and positive and negative affect were assessed daily for 30 days via diaries in 228 men and women diagnosed with RA. Days of higher than average daily positive events were associated with both decreased same-day fatigue and increased next-day fatigue, but only among women. Sex differences in same-day relations between positive events and fatigue were mediated by increases in positive affect. For both sexes, days of higher than average daily negative events related to increased same-day and next-day fatigue, and the same-day relations between negative events and fatigue were mediated by increases in negative affect. A more nuanced understanding of similarities and differences between men and women in the associations between changes in interpersonal events and fatigue may inform future interventions for RA fatigue. 相似文献
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Fatigue is a common symptom of advanced cancer limiting one''s activity and affecting the quality of life. It is a multidimensional symptom complex with subjective and objective components. Hence, its definition and assessment seems arbitrary, incomplete, and elusive. Components of fatigue often merge with other ‘disease states’ as anemia, depression and so on, compounding difficulty to assess it separately. Fatigue has a high prevalence rate, and lasts longer in chronic diseases like cancer. Its association with treatment modalities like chemotherapy, radiotherapy alongside the primary disease process makes it seemingly ubiquitous in many cases. Systemic manifestation of cancer causes excess demand on body resources on cell repair, uncontrolled growth with metabolite accumulation causing fatigue. Co-morbid conditions of organic and psychological nature causes fatigue. There are many assessment tools for fatigue with different uses and objectives, simple and reproducible tools like Brief Fatigue Inventory, Edmonton Symptom assessment scale seem feasible in everyday practice. Management of fatigue is not straightforward and rewarding. Although treatment of cause appears to be an attractive option, it is not possible in all cases. Therapeutic agents targeting cytokine load is in early stages of study and available results are not favorable. Specific measures aimed at pain relief, prevention/treatment of sepsis, management of depression, avoidance of drugs causing fatigue, restoring the metabolic profile are important. Methyl phenidate, megestrol, and modafinil are some drugs with promising effect to treat fatigue, though confirmatory studies are yet to be established. Non-pharmacological methods are also helpful. Forewarning patients on upcoming fatigue, active regular exercise, and stress management are some of them. Fatigue being a multidimensional entity, single mode of therapy is insufficient. Combined modality tailored to individual patient need and understanding may be the right way to battle this ill-understood symptom. This review article examines the etiopathogenesis and management strategies of fatigue in cancer. 相似文献
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【摘要】目的 了解孕妇疲乏发生率和疲乏程度;探讨孕妇疲乏的影响因素。方法 通过整群抽样法选取上海市某三甲妇产科专科医院338例孕妇,通过自行汉化的疲乏量表(PAFS)调查孕期疲乏现况,通过自行设计的一般资料调查表获取孕妇人口学资料。结果 孕妇孕28周期间疲乏发生率高,但仅为“偶尔发生”。在控制职业、本次是否计划妊娠、睡眠时间和妊娠合并症或并发症类型之后,睡眠质量仍然是影响孕期疲乏的变量(F=15.31 P=0.000)。结论 孕妇孕28周期间疲乏普遍存在,但程度较轻。孕妇睡眠质量不佳是孕妇疲乏的重要因素。医护人员及家属应关注并采取有效措施帮助孕妇提高睡眠质量,缓解孕期疲乏。 相似文献