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Scheffé Test (scheffé + test)
Selected AbstractsFibre type composition of the human psoas major muscle with regard to the level of its originJOURNAL OF ANATOMY, Issue 6 2009Juraj Arbanas Abstract The aim of our study was to explore the fibre type composition of the human psoas major muscle at different levels of its origin, from the first lumbar to the fourth lumbar vertebra, and to compare the muscle fibre size and distribution of different fibre types between levels with respect to its complex postural and dynamic function. Muscle samples were collected from 15 young males (younger than 35 years). Serial transverse sections (5 ,m) of the samples were cut by cryomicrotome. Type I, IIA and IIX muscle fibres were typed using myosin heavy chain identification. The serial sections were analysed using a light microscope with a magnitude of 100×. The differences between measurements were evaluated using a repeated-measures anova and Scheffé test for post-hoc analysis. Our study showed that the human psoas major muscle was composed of type I, IIA and IIX muscle fibres. It had a predominance of type IIA muscle fibres, whereas type I muscle fibres had the largest cross-sectional area. Type IIX muscle fibres were present as a far smaller percentage and had the smallest cross-sectional area. Moreover, the fibre type composition of the psoas major muscle was different between levels of its origin starting from the first lumbar to the fourth lumbar vertebra. We conclude that the fibre type composition of the psoas major muscle indicated its dynamic and postural functions, which supports the fact that it is the main flexor of the hip joint (dynamic function) and stabilizer of the lumbar spine, sacroiliac and hip joints (postural function). The cranial part of the psoas major muscle has a primarily postural role, whereas the caudal part of the muscle has a dynamic role. [source] Wear of human enamel and nano-filled composite resin denture teeth under different loading forcesJOURNAL OF ORAL REHABILITATION, Issue 1 2009M. GHAZAL Summary, To evaluate and correlate the two-body wear of human enamel and nano-filled composite resin teeth with the loading forces used in a dual-axis chewing simulator. Three groups of human enamel and three of nano-filled composite resin teeth were tested in a chewing simulator. Zirconia ceramic balls were used as antagonists. The teeth were tested with three different loading forces (20, 49 and 78 N). Wear was analysed by measuring the volume and vertical substance loss using a laser scanner after 300000 chewing cycles. Data were statistically analysed using two-way anova followed by the Scheffé test (P , 0·05). Spearman correlation test was used to determine whether there was a relationship between the loading force and the degree to which the human enamel and composite resin had worn. An increase in the loading force significantly increased the wear of composite resin and of human enamel. The effect of the loading force on the wear was statistically significant at the 0·001 level. Human enamel showed a lower volume and vertical substance loss than composite resin under loading forces of 20 and 49 N and lower vertical loss under loading force of 78 N. The correlation between the volume loss and loading force was statistically significant (r = 0·616, P < 0·001). Nano-filled composite resin and human enamel exhibited different amount of wear under different loading forces. In general, human enamel showed less vertical substance loss than nano-filled composite resin. [source] Fracture Resistance of Endodontically Treated Teeth: Three Walls versus Four Walls of Remaining Coronal Tooth StructureJOURNAL OF PROSTHODONTICS, Issue 1 2009Siriporn Arunpraditkul DDS Abstract Purpose: The purpose of this study was to evaluate the fracture resistance of endodontically treated teeth between those with four walls and those with three walls of remaining coronal tooth structure and the effect of the site of the missing coronal wall. Materials and Methods: Thirty-two endodontically treated second mandibular premolars were decoronated, leaving 3 mm above the cementoenamel junction (CEJ). A 0.5-mm-wide chamfer was prepared 1 mm above the CEJ. The teeth were randomly divided into four groups. Group 1 had four walls of coronal tooth structure, whereas groups 2, 3, and 4 had only three walls, missing the buccal, lingual, and mesial wall, respectively. The cast dowel and cores and crowns (Ni,Cr alloy) were cemented with zinc phosphate cement. A compressive load was applied 45° to the long axis, 2 mm below the buccal cusp, with an Instron machine until failure at a crosshead speed of 5 mm/min. Failure load (kg) and mode of failure were recorded. Data were analyzed with one-way ANOVA and Scheffé tests (p < 0.05). Results: Group 1 had the highest fracture resistance (1190.3 ± 110.5 kg), significantly different from the other groups (p < 0.05) (group 2: 578.5 ± 197.4 kg; group 3: 786.6 ± 132.8 kg; group 4: 785.4 ± 289.9 kg). There were no significant differences among the test groups. The mode of failure in group 1 was a horizontal root fracture, whereas that of the other groups was either vertical or oblique fracture. Conclusions: Teeth with four walls of remaining coronal dentine had significantly higher fracture resistance than teeth with only three walls. The site of the missing coronal wall did not affect the fracture resistance of endodontically treated teeth. [source] Implant Surface Modification Using Laser Guided Coatings: In Vitro Comparison of Mechanical PropertiesJOURNAL OF PROSTHODONTICS, Issue 5 2008Asvin Vasanthan DDS Abstract Purpose: Plasma-sprayed hydroxyapatite (HA)-coated implants show failures along the coating,substrate interface due to poor bond strength. We analyzed HA coatings obtained by pulsed laser deposition (PLD) and compared them to commercially used plasma-sprayed coatings with respect to their bond strength to titanium alloy (Ti-6Al-4V), as well as surface roughness alterations produced by each of the two deposition methods. Materials and Methods: Twelve titanium alloy disks were plasma-sprayed under commercial implant coating conditions, and 24 titanium alloy disks were coated using PLD. All coatings were characterized by the presence of the different calcium phosphate (CaP) phases. The plasma-sprayed coatings (n = 12) were predominantly HA, and the pulsed laser-deposited coatings were hydroxydyapatite (n = 12) and HA coating with a tetra calcium phosphate (TTCP) phase (n = 12). The surface roughness was analyzed before and after the coating processes to assess roughness changes to the surface by the coatings. The adhesive bond strengths of these coatings to the substrate titanium alloy was tested and compared. Scheffé's test was used to analyze the statistical significance of the data. Results: The surface roughness alteration following PLD was a decrease of 0.2 ,m, whereas following plasma spraying the decrease was 1.0 ,m. Bond strengths were as follows [mean (SD) in MPa]: pulsed laser-deposited HA coatings: 68.3 (17.8); pulsed laser-deposited HA with tetra-CaP: 55.2 (21.1); plasma-sprayed HA 17.0 (2.8). The multivariate Scheffé's test revealed that HA coatings obtained by PLD had significantly increased bond strengths compared with the plasma sprayed ones (p, 0.05). Conclusions: HA coatings obtained by PLD showed greater adherence to titanium alloy. PLD offers an alternative method to produce thinner coatings with better adherence properties, along with precise control over the deposition process. [source] | ||||||||||