945 resultados para Statistical analysis methods
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The Sciatic Functional Index (SFI) is a quite useful tool for the evaluation of functional recovery of the sciatic nerve of rats in a number of experimental injuries and treatments. Although it is an objective method, it depends on the examiner`s ability to adequately recognize and mark the previously established footprint key points, which is an entirely subjective step, thus potentially interfering with the calculations according to the mathematical formulae proposed by different authors. Thus, an interpersonal evaluation of the reproducibility of an SFI computer-aided method was carried out here to study data variability. A severe crush injury was produced on a 5 mm-long segment of the right sciatic nerve of 20 Wistar rats (a 5000 g load directly applied for 10 min) and the SH was measured by four different examiners (an experienced one and three newcomers) preoperatively and at weekly intervals from the 1st to the 8th postoperative week. Three measurements were made for each print and the average was calculated and used for statistical analysis. The results showed that interpersonal correlation was high (0.82) in the 3rd, 4th, 5th, 7th and 8th weeks, with an unexpected but significant (p < 0.01) drop in the 6th week. There was virtually no interpersonal correlation (correlation index close to 0) on the 1st and 2nd weeks, a period during which the variability between animals and examiners (p =0.24 and 0.32, respectively) was similar, certainly due to a poor definition of the footprints. The authors conclude that the SFI method studied here is only reliable from the 3rd week on after a severe lesion of the sciatic nerve of rats. (C) 2008 Elsevier B.V. All rights reserved.
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Purpose: The purpose of our study was to compare signal characteristics and image qualities of MR imaging at 3.0 T and 1.5 T in patients with diffuse parenchymal liver disease. Materials and methods: 25 consecutive patients with diffuse parenchymal liver disease underwent abdominal MR imaging at both 3.0 T and 1.5 T within a 6-month interval. A retrospective study was conducted to obtain quantitative and qualitative data from both 3.0 T and 1.5 T MRI. Quantitative image analysis was performed by measuring the signal-to-noise ratios (SNRs) and the contrast-to-noise ratios (CNRs) by the Students t-test. Qualitative image analysis was assessed by grading each sequence on a 3- and 4-point scale, regarding the presence of artifacts and image quality, respectively. Statistical analysis consisted of the Wilcoxon signed-rank test. Results: the mean SNRs and CNRs of the liver parenchyma and the portal vein were significantly higher at 3.0 T than at 1.5 T on portal and equilibrium phases of volumetric interpolated breath-hold examination (VIBE) images (P < 0.05). The mean SNRs were significantly higher at 3.0 T than at 1.5 T on T1-weighted spoiled gradient echo (SGE) images (P < 0.05). However, there were no significantly differences on T2-weighted short-inversion-time inversion recovery (STIR) images. Overall image qualities of the 1.5 T noncontrast T1- and T2-weighted sequences were significantly better than 3.0 T (P < 0.01). In contrast, overall image quality of the 3.0 T post-gadolinium VIBE sequence was significantly better than 1.5 T (P< 0.01). Conclusions: MR imaging of post-gadolinium VIBE sequence at 3.0 T has quantitative and qualitative advantages of evaluating for diffuse parenchymal liver disease. (C) 2008 Elsevier Ireland Ltd. All rights reserved.
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The mechanical alterations related to the excessive use of accessory respiratory muscles and the mouth breathing observed in children with asthma may lead to the development of alterations in head posture, shoulders, thoracic region and, consequently, in alterations of body posture. The purpose of this study was to assess body posture changes of children with asthma compared to a non-asthmatic control group matched for gender, age, weight, and height. Thirty children with asthma and 30 non-asthmatic children aged 7 to 12 years were enrolled in this study. Digital photographic records were obtained for analysis of the body posture of the children by computed photogrammetry. The intraclass correlation coefficient and Student`s t test (p < 0.05) were used for statistical analysis. There were no significant differences between groups for the angles analyzed, except for the knee flexor angle. These results demonstrate that children with asthma did not present postural alterations compared to non-asthmatic controls since the only angle for which there was a significant difference between groups showed weak reproducibility. The findings of this study do not support the notion that children with asthma present alterations in body posture.
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Objectives: The objective of the present study was to evaluate intraluminal esophageal pressure during voice and speech emission in speaking laryngectomees with a tracheoesophageal prosthesis. Methods: In our prospective analysis in a tertiary-care academic hospital, 25 laryngectomees were divided into 2 groups: 11 speaking individuals with a tracheoesophageal prosthesis and a control group of 14 nonspeaking laryngectomees. All patients were subjected to manometry during voice and speech emission tests. We determined the pressures achieved in the distal, middle, and proximal parts of the esophagus. Results: Statistical analysis revealed that the amplitude of pressure in the distal esophagus during sound emission was higher in speaking laryngectomees; in the middle esophagus, intraluminal pressure during emission of the sentence was higher in speaking subjects, and in the proximal esophagus there was no difference between the groups. Conclusions: During the manometric evaluation of the distal and middle esophagus in the presence of voice and speech emission, the intraluminal pressure revealed a significant difference for the speaking laryngectomees with a tracheoesophageal prosthesis. The proximal esophagus behaved similarly in the groups of speakers and nonspeakers. Speaking laryngectomees with a tracheoesophageal prosthesis depend on a differentiated performance of the middle and distal parts of the esophagus.
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Objective: In the literature there is no validated instrument for the clinical evaluation of the orofacial myofunctional condition of children that will permit the examiner to express numerically his perception of the characteristics and behaviors observed. The proposal of this study is to describe a protocol for the evaluation of children aged 6-12 years in order to establish relations between the orofacial. myofunctional conditions and numerical scales. The protocol validity, reliability of the examiners and agreement between them was analyzed. Methods: Eighty children aged 6-12 years participated in the study. All were evaluated and 30 were selected at random for the analyses (age range: 72-149 months, mean = 103.3, S.D. = 23.57). Individuals with and without orofacial myofunctional. disorders were included. The examiners were two speech therapists property calibrated in orofacial myofunctional evaluation. Two protocols were constructed. One, based on traditional models, was called traditional orofacial. myofunctional. evaluation (TOME), and the other, with the addition of numerical scales, was called orofacial myofunctional. evaluation with scores (OMES). The clinical conditions included were: appearance, posture and mobility of lips, tongue, cheeks and jaws, respiration, mastication and deglutition. Statistical analysis was performed using the split-half reliability method. Means, standard deviations and the Spearman correlation coefficient were also calculated. Results: There was a statistically significant correlation between the evaluations of 30 children assessed with the TOME and OMES protocols (r = 0.85, p < 0.01). The reliability between protocols was 0.92. The test-retest reliability of the OMES instrument was 0.99 and the correlation was 0.98. Reliability between examiners 1 and 2 using the OMES protocol was 0.99, and the correlation was 0.98 (P < 0.01). Conclusion: The OMES protocot proved to be a valid and reliable instrument for orofacial myofunctional evaluation, permitting the grading of orofacial myofunctional conditions within the limits of the selected items. (c) 2007 Elsevier Ireland Ltd. All rights reserved.
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Retention systems for implant-retained auricular prostheses using either bar-clip attachments with 2 or 3 clips or retention with 2 or 3 magnets were wear tested (insertion and removal cycles) to simulate clinical periods of use. Measurements were taken at intervals of 540 cycles, which represents a period of use of approximately 6 months, for up to 3,240 cycles. Assessments of retentive force were carried out before, during, and after the wear test. Statistical analysis indicated that the bar-clip systems provided higher retention than the magnetic systems. The bar-clip attachment with 2 clips showed a significant loss of retentive force after wear testing (P < .05), suggesting lower durability and shorter clinical life. The retention provided by the bar-clip attachment with 3 clips remained stronger than that provided by all other systems tested. At the end of the wear test, the magnetic systems showed very little loss of retention but were still less retentive than the bar-clip systems, suggesting higher durability under clinical simulation despite the lower retention initially provided.
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The purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser (2.94 mu m) irradiation on the removal of root surface smear layer of extracted human teeth and to compare its efficacy with that of citric acid, ethylenediamine tetra-acetic acid (EDTA), or a gel containing a mixture of tetracycline hydrochloride (HCl) and citric acid, using scanning electron microscopy (SEM). Thirty human dentin specimens were randomly divided into six groups: G1 (control group), irrigated with 10 ml of physiologic saline solution; G2, conditioned with 24% citric acid gel; G3, conditioned with 24% EDTA gel; G4, conditioned with a 50% citric acid and tetracycline gel; G5, irradiated with Er:YAG laser (47 mJ/10 Hz/5.8 J/cm(2)/pulse); G6, irradiated with Er:YAG laser (83 mJ/10 Hz/10.3 J/cm(2)/pulse). Electron micrographs were obtained and analyzed according to a rating system. Statistical analysis was conducted with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). G1 was statistically different from all the other groups; no statistically significant differences were observed between the Er:YAG laser groups and those undergoing the other treatment modalities. When the two Er:YAG laser groups were compared, the fluency of G6 was statistically more effective in smear layer removal than the one used in G5 (Mann-Whitney test, P < 0.01). Root surfaces irradiated by Er:YAG laser had more irregular contours than those treated by chemical agents. It can be concluded that all treatment modalities were effective in smear layer removal. The results of our study suggest that the Er:YAG laser can be safely used to condition diseased root surfaces effectively. Furthermore, the effect of Er:YAG laser irradiation on root surfaces should be evaluated in vivo so that its potential to enhance the healing of periodontal tissues can be assessed.
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Purpose: To evaluate the influence of cleaning procedures (pumice, anionic detergent and both procedures together) on the tensile bond strength of etch-and-rinse and self-etch adhesive systems to bovine enamel and dentin in vitro. Methods: Eighty non-carious, bovine incisors were extracted, embedded in acrylic resin to obtain enamel/dentin specimens. Flat bonding surfaces were obtained by grinding. Groups were divided according to substrate (enamel or dentin), adhesive system [etch-and-rinse, Adper Single Bond 2 (SB) or self-etch, Clearfil Protect Bond (PB)]; and cleaning substances (pumice, anionic detergent and their combination). The teeth were randomly divided into 20 groups (n=8): G1 - Enamel (E) + SB; G2 -E + oil (O) + SB; G3 - E + O + Pumice (P) + SB; G4 - E + O + Tergentol (T) + SB; G5 - E + O + P + T + SB; G6 - E + PB; G7 - E + O + PB; G8 - E + O + P + PB; G9 - E + O + T + PB; GIO - E + O + P + T + PB; G11 - Dentin (D) + SB; G12 D + SB + O; G13 - D + SB + O + P; G14 - D + SB + O + T; G15 - D + SB + O + P + T; G16 - D + PB; G17 - D + O + PB +; G18 - D + O + P + PB; G19 - D + O + T + PB; G20 - D + O + P + T + PB. Specimens were contaminated with handpiece oil for 5 seconds before bonding. Adhesive systems and resin composite were applied according to manufacturers` instructions. Specimens were tested in tension after 24 hours of immersion using a universal testing machine at a crosshead speed of 0.5 mm/minute. Bond strengths were analyzed with ANOVA. Failure sites were observed and recorded. Results: Tensile bond strength in MPa were: G1 (23.6 +/- 0.9); G2 (17.3 +/- 2.2); G3 (20.9 +/- 0.9); G4 (20.6 +/- 0.5); G5 (18.7 +/- 2.3); G6 (23.0 +/- 1.0); G7 (21.5 +/- 2.4); G8 (19.9 +/- 1.3); G9 (22.1 +/- 1.2); G10 (19.1 +/- 1.2); G11 (18.8 +/- 1.3); G12 (15.7 +/- 2.1); G13 (17.8 +/- 3.3); G14 (15.3 +/- 2.9); G15 (15.6 +/- 1.9); G16 (14.7 +/- 2.3); G17 (5.5 +/- 0.9); G18 (19.3 +/- 1.8); G19 (15.6 +/- 1.6); G20 (20.3 +/- 3.9). Statistical analysis showed that the main factors substrate and cleaning were statistically significant, as well as the triple interaction between factors of variance. However, the factor adhesive system did not show statistical difference. Oil contamination reduced bond strengths, being less detrimental to enamel than to dentin. Etch-and-rinse (SB) and two-step self-etch (PB) systems had similar bond strengths in the presence of oil contamination. For etch-and-rinse (SB), the cleaning procedures were able to clean enamel, but dentin was better cleaned by pumice. When self-etch (PB) system was used on enamel, anionic detergent was the best cleaning substance, while on dentin the tested procedures were similarly efficient.
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Background: The aim of this study was to evaluate the cardiovascular effects of maxillary infiltration using 2% lidocaine with 1: 100 000 adrenaline, 4% articaine with 1: 200 000 adrenaline, and 4% articaine with 1: 100 000 adrenaline in different stages during restorative dental procedures. Methods: Twenty healthy patients randomly received 1.8 mL of the three local anaesthetics. Systolic blood pressure, average blood pressure, diastolic blood pressure, and heart rate were evaluated by the oscillometric and photoplethysmograph methods in seven stages during the appointment. Results: Statistical analysis by ANOVA and Tukey tests of cardiovascular parameters did not show significant differences between the anaesthetic associations. There were significant differences for the parameters among different clinical stages. Conclusions: The variation of cardiovascular parameters was similar for lidocaine and articaine with both adrenaline concentrations and showed no advantage of one drug over the other. Cardiovascular parameters were influenced by the stages of the dental procedures, which showed the effect of anxiety during restorative dental treatment.
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P>Aim To compare the percentage of gutta-percha, sealer and voids and the influence of isthmuses in mesial root canals of mandibular molars filled with different techniques. Methodology Canals in 60 mesial roots of mandibular first molars were prepared with ProTaper instruments to size F2 (size 25, 0.08 taper) and filled using a single-cone, lateral compaction, System B or Thermafil techniques. An epoxy resin sealer was labelled with Rhodamine-B dye to allow analysis under a confocal microscope. The percentage of gutta-percha, sealer and area of voids was calculated at 2, 4 and 6 mm from the apex, using Image Tool 3.0 software. Statistical analysis was performed using nonparametric Kruskal-Wallis and Dunn tests (P < 0.05). The influence of isthmuses on the presence or absence of voids was evaluated using the Fisher test. Results At the 2 mm level, the percentage of gutta-percha, sealer and voids was similar amongst the System B, lateral compaction and single-cone techniques. The single-cone technique revealed significantly less gutta-percha, more sealer and voids in comparison with the Thermafil technique at the 2 and 4 mm level (P < 0.05). The analysis of all sections (2, 4 and 6 mm) revealed that more gutta-percha and less sealer and voids were found in root canals filled with Thermafil and System B techniques (P < 0.05). The Fisher test revealed that the presence of isthmuses increased the occurence of voids in the lateral compaction group only (P < 0.05). Conclusion Gutta-percha, sealer filled area and voids were dependent on the canal-filling technique. The presence of isthmuses may influence the quality of root filling.
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Introduction: Fibroblasts are the most abundant cells in dental pulp. To investigate their capacity to produce the chemokines CCL3, CXCL8, and CXCL12 as well as nitric oxide (NO), we evaluated the production of these mediators in supernatants of cultured human dental pulp fibroblasts (HDPF) stimulated by heat-killed Enterococcus faecalis (HKEF). Methods: Primary cultures of HDPF were stimulated with medium alone or HKEF (1:1, 10:1, or 100:1 bacteria:fibroblast) for 1, 6, and 24 hours. Chemokines and NO were assessed through enzyme-linked immunosorbent assay and Griess reaction, respectively. Statistical analysis was performed by using analysis of variance and Tukey post test. Results: CCL3 was not detected, whereas constitutive CXCL8 was not affected. Production of CXCL12 was increased at 1 and 6 hours, and NO was increased at the concentration of 1:1 bacteria:fibroblast at 24 hours. Viability and proliferation assays did not reveal cell number differences. Conclusions: These findings demonstrate that heat-killed E. faecalis is able to increase production of CXCL12 and NO by HDPF. (J Endod 2010;36:91-94)
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Objective: Congenital bilateral perisylvian syndrome (CBPS) is frequently caused by polymicrogyria (PMG). The aim of this study was to correlate the clinical and psycholinguistic aspects with neuroradiological data of patients with CBPS. Methods: Thirty-one patients were studied. We performed a clinical investigation of the patients and their families, including MRI scanning, neuropsychological tests and language evaluation. Results: The statistical analysis showed that: a) prenatal events are associated with the non-familial type of PMG; b) diffuse PMG is associated with pseudobulbar signs, as opposed to BPPP; c) motor deficit is associated with diffuse PMG; d) epilepsy is equally present in patients with both familial or non-familial PMG, but is more frequently seen in patients with diffuse PMG; e) dyslexia and SLI can be a feature of both the diffuse or BPPP, and either familial or sporadic cases of PMG. Conclusions: The severity of clinical manifestations in CBPS is correlated with the extent of cortical involvement. Most patients with CBPS have a history of speech delay or language difficulties and no epilepsy. Dyslexia can be found in patients with PMG.
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Purpose: To test the strength to failure and fracture mode of three indirect composite materials directly applied onto Ti-6Al-4V implant abutments vs cemented standard porcelain-fused-to-metal (PFM) crowns. Materials and Methods: Sixty-four locking taper abutments were randomly allocated to four groups and were cleaned in ethanol in an ultrasonic bath for 5 min. After drying under ambient conditions, the abutments were grit blasted and a custom 4-cusp molar crown mold was utilized to produce identical crowns (n = 16 per group) of Tescera (Bisco), Ceramage (Shofu), and Diamond Crown (DRM) according to the manufacturer`s instructions. The porcelain-fused-to-metal crowns were fabricated by conventional means involving the construction and a wax pattern and casting of a metallic coping followed by sintering of increasing layers of porcelain. All crowns were loaded to failure by an indenter placed at one of the cusp tips at a 1 mm/min rate. Subsequently, fracture analysis was performed by means of stereomicroscopy and scanning electron microscopy. One-way ANOVA at 95% level of significance was utilized for statistical analysis. Results: The single load to failure (+/- SD) results were: Tescera (1130 +/- 239 N), Ceramage (1099 +/- 257 N), Diamond Crown (1155 +/- 284 N), and PFM (1081 +/- 243 N). Stereomicroscopy analysis showed two distinct failure modes, where the loaded cusp failed either with or without abutment/metallic coping exposure. SEM analysis of the fractures showed multiple crack propagation towards the cervical region of the crown below a region of plastic deformation at the indenter contact region. Conclusion: The three indirect composites and PFM systems fractured at loads higher than those typically associated with normal occlusal function. Although each material had a different composition and handling technique, no significant differences were found concerning their single load to fracture resistance among composite systems and PFM.
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Introduction: Recently developed portable dental X-ray units increase the mobility of the forensic odontologists and allow more efficient X-ray work in a disaster field, especially when used in combination with digital sensors. This type of machines might also have potential for application in remote areas, military and humanitarian missions, dental care of patients with mobility limitation, as well as imaging in operating rooms. Objective: To evaluate radiographic image quality acquired by three portable X-ray devices in combination with four image receptors and to evaluate their medical physics parameters. Materials and methods: Images of five samples consisting of four teeth and one formalin-fixed mandible were acquired by one conventional wall-mounted X-ray unit, MinRay (R) 60/70 kVp, used as a clinical standard, and three portable dental X-ray devices: AnyRay (R) 60 kVp, Nomad (R) 60 kVp and Rextar (R) 70 kVp, in combination with a phosphor image plate (PSP), a CCD, or a CMOS sensor. Three observers evaluated images for standard image quality besides forensic diagnostic quality on a 4-point rating scale. Furthermore, all machines underwent tests for occupational as well as patient dosimetry. Results: Statistical analysis showed good quality imaging for all system, with the combination of Nomad (R) and PSP yielding the best score. A significant difference in image quality between the combination of the four X-ray devices and four sensors was established (p < 0.05). For patient safety, the exposure rate was determined and exit dose rates for MinRay (R) at 60 kVp, MinRay (R) at 70 kVp, AnyRay (R), Nomad (R) and Rextar (R) were 3.4 mGy/s, 4.5 mGy/s, 13.5 mGy/s, 3.8 mGy/s and 2.6 mGy/s respectively. The kVp of the AnyRay (R) system was the most stable, with a ripple of 3.7%. Short-term variations in the tube output of all the devices were less than 10%. AnyRay (R) presented higher estimated effective dose than other machines. Occupational dosimetry showed doses at the operator`s hand being lowest with protective shielding (Nomad (R): 0.1 mu Gy). It was also low while using remote control (distance > 1 m: Rextar (R) < 0.2 mu Gy, MinRay (R) < 0.1 mu Gy). Conclusions: The present study demonstrated the feasibility of three portable X-ray systems to be used for specific indications, based on acceptable image quality and sufficient accuracy of the machines and following the standard guidelines for radiation hygiene. (C) 2010 Elsevier Ireland Ltd. All rights reserved.
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Purpose: To verify the influence of cavity access diameter on demineralized dentin removal in the ART approach. Methods: 40 non-carious human premolars were randomly divided into four groups. The occlusal surface was ground flat and the teeth were sectioned mesio-distally. The hemi-sections were reassembled and occlusal access preparations were carried out using ball-shaped diamonds. The resulting size of the occlusal opening was 1.0 mm, 1.4 mm, 1.6 mm and 1.8 mm for Groups A, B, C, and D, respectively. Standardized artificial carious lesions were created and demineralized dentin was excavated. After excavation, the cavities were analyzed using: (a) the tactile method, (b) caries-detection dye to stain demineralized dentin, as proposed by Smales & Fang, and (c) Demineralized Tissue Removal index, as proposed in this study. Statistical analysis was performed using Fisher, Spearman correlation coefficient, kappa, Kruskal-Wallis and Miller tests (P < 0.05). Results: The three methods of evaluation showed no significant difference between Groups A vs. B, and C vs. D, while statistically significant differences were observed between Groups A vs. C, A vs. D, B vs. C and B vs. D. Based on the results of this study, the size of occlusal access significantly affected the efficacy of demineralized tissue removal.