• Imaging Science in Dentistry
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• v.39 no.3
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• pp.133-147
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• 2009

Purpose : To investigate the reproducibilities and compare the measurements in digital and MDCT-synthesized cephalometric radiograph, and to investigate the effect of head position on the measurement during imaging with MDCT. Materials and Methods : Twenty-two dry skulls (combined with mandible) were used in this study. Conventional digital cephalometric radiograph was taken in standard position, and MDCT was taken in standard position and two rotated position ($10^{\circ}$ left rotation and $10^{\circ}$ right tilting). MDCT data were imported in $OnDemand^{(R)}$ and lateral cephalometric radiograph were synthesized from 3D virtual models. Two types of rotated MDCT data were synthesized with default mode and with corrected mode using both ear rods. For all six images, sixteen angular and eleven linear measurements were made in V-$Ceph^{(R)}$ three times. Reproducibility of measurements was assessed using repeated measures ANOV A and ICC. Linear and angular measurements were compared between digital and five MDCT-synthesized images by Student t-test. Results : All measurements in six types of cephalometric radiograph were not statistically different under ICC examination. Measurements were not different between digital and MDCT-synthesized images (P>.05). Measurements in MDCT-synthesized image in $10^{\circ}$ left rotation or $10^{\circ}$ right tilting position showed possibility of difference from digital image in some measurements, and possibility of improvement via realignment of head position using both ear rods. Conclusion : MDCT-synthesized cephalometric radiograph can substitute conventional cephalometric radiograph. The error on head position during imaging with MDCT have possibility that can produce measurement errors with MDCT-synthesized image, and these position error can be corrected by realignment of the head position using both ear rods.

• Restorative Dentistry and Endodontics
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• v.29 no.2
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• pp.170-176
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• 2004

Objectives : In the unique metal iris method. the developing interfacial gap at the cavity floor resulting from the cavity wall property during polymerizing composite resin might affect the nominal shear bond strength values. The aim of this study is to evaluate that the iris method reduces the cohesive failure in the substrates and the cavity wall property effects on the shear bond strength tests using iris method. Materials and Methods : The occlusal dentin of 64 extracted human molars were randomly divided into 4 groups to simulate two different levels of cavity wall property (metal and dentin iris) and two different materials ($ONE-STEP^{\circledR}$ and $ALL-BOND^{\circledR}$ 2) for each wall property. After positioning the iris on the dentin surface. composite resin was packed and light-cured. After 24 hours the shear bond strength was measured at a crosshead speed of 0.5 mm/min. Fracture analysis was performed using a microscope and SEM. The data was analyzed statistically by a two-way ANOV A and t-test. Results : The shear bond strength with metal iris was significant higher than those with dentin iris (p＝0.034). Using $ONE-STEP^{\circledR}$, the shear bond strength with metal iris was significant higher than those with dentin iris (p＝0.005), but not in $ALL-BOND^{\circledR}$ 2 (p＝0.774). The incidence of cohesive failure was very lower than other shear bond strength tests that did not use iris method. Conclusions：The iris method may significantly reduce the cohesive failures in the substrates. According to the bonding agent systems. the shear bond strength was affected by the cavity wall property.

• Korean journal of food and cookery science
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• v.19 no.4
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• pp.529-538
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• 2003

The objectives of this study were to measure customers' cognition and overall satisfaction, and to identify relatively important attributes for the overall satisfaction, of home-delivered meals. Questionnaires were distributed to 243 customers. The statistical data analyses were completed by x$^2$-tests, ANOV A, factor analysis, reliability analysis and regression analysis using SPSS version 10. 56.6% of customers get obtained information from the internet, with 31.3% of these using this method at least once a week, but 72.9% of customers used this method less than once per years. The major reasons for ordering home-delivered meals were tired of cooking, more economical and no time to cook. The results were significantly different in relation to age, occupation and monthly income. The major reasons for hesitation about ordering home-delivered meals were meals should be prepared in households, not sanitary and the use of too many artificial flavors. The results for this factor were significantly different in relation to gender, age and monthly income(p<0.01). The most preferred kinds of home-delivery meals were Korean soup (guk), stew, soup (tang), speciality dishes and party dishes. The customer's cognition of kindness of the delivery staff was highest, with food temperature being the lowest among the options. The food and service level factors were derived from a factor based analysis of customer's cognition towards home-delivered meals. The customer's cognition of food taste, food quantity, kindness of delivery staff and packaging container shape were significantly different according to the use frequency and use period. The packaging method, sanitation, kindness of delivery staff, price and taste were the most relatively important attributes for overall satisfaction with home-delivered meals.