Color comparison of glaze-treated multi-coloured lithium disilicate and zirconia / 대한치과재료학회지

The purpose of this study was to investigate the effect of glazing treatment of multi-colored zirconia disc and lithium disilicate block on the optical properties. From an Ultra Translucent Multi-Layered (UTML) disc containing 50% cubic crystal and a lithium disilicate-based Amber Mill Direct (AMD) block, the 1.2 mm thick specimens of the upper layer (T), the center (M), and the lower layer (B) were prepared. Three types of paste glaze of InSync Glaze Paste, IPS E.max Ceram Glaze Paste, and Amber Ceram G7 Glaze Paste were applied and fired to a uniform thickness on the surface of the specimen. CIE L * , a * , b * values were measured using a spectrophotometer and contrast and translucency were calculated. The bonding interface with the glaze layer was observed using HR FE-SEM. In the glazed groups, L * value increased, but a * value and b * value decreased. The translucency value measured in the untreated group was statically higher in the AMD groups than in UTML groups (P0.05), but significantly decreased compared to the untreated group after glazing treatment in the AMD group (P<0.05). The contrast ratios generally increased after glaze treatment compared to the untreated group. Since the glaze treatment can affect the optical properties of ceramic restorations, the choice of glaze should be considered important for the desired color by the dental technician.

Effect of the cutting flute of the orthodontic miniscrew on insertion and removal torque / 대한치과재료학회지

The purpose of this study was to evaluate the structural characteristics of the thread length of orthodontic mini-screws and the effects of insertion and removal torques according to the formation of the cutting flute. Two types of mini-screws were made, with a thread length of 6.0 mm and a thread length of 3.3 mm. In order to examine the effect of flute formation, the experiment group was divided into a miniscrew test group with flute formation and an experiment group without flute formation. To evaluate the effect of flute formation, two flutes were formed at 180°on the circumference, and at the tip of the mini screw, up to 4 mm for thread length of 6.0 mm and 2.4 mm for thread length of 3.3 mm. A biomechanical test block formed of 2 mm cortical bone and 10 mm cancellous bone was used to eliminate the influence of the difference in cortical bone thickness and bone density according to the insertion site. 1 mm diameter guide hole was drilled on the test block and the mini-screw was placed vertically. Using a 0.1 N·cm precision digital torque gauge, the maximum torque value was recorded at this time by embedding it to the top of the screw under a static load of 1.2 kg and the value when it was removed in the opposite direction. The insertion torque values for the 6.0 mm and 3.3 mm length mini screws were (29.53±1.84) N·cm and (26.84±2.15) N·cm, and the removal torque values are (14.50±1.37) N·cm and (13.15±2.89) N·cm, respectively.There were no statistically significant differences (P>0.05). The flute of 6.0 mm mini-screws had no statistically significant difference in both insertion and removal torque values and increased to (30.13±1.97) N·cm and (18.65±1.10) N·cm (P>0.05). In experiments with 3.3 mm mini-screws, the insertion and removal torque values decreased to (20.99±3.94) N·cm and (11.32±2.03) N·cm, respectively, showing a statistically significant decrease only in the insertion torque values (P<0.05). The insertion and removal torque values of the mini-screw were not significantly increased even when the screw length was doubled, and the flute formation effect was different with the screw length.

Color comparison of glaze-treated multi-coloured lithium disilicate and zirconia / 대한치과재료학회지

The purpose of this study was to investigate the effect of glazing treatment of multi-colored zirconia disc and lithium disilicate block on the optical properties. From an Ultra Translucent Multi-Layered (UTML) disc containing 50% cubic crystal and a lithium disilicate-based Amber Mill Direct (AMD) block, the 1.2 mm thick specimens of the upper layer (T), the center (M), and the lower layer (B) were prepared. Three types of paste glaze of InSync Glaze Paste, IPS E.max Ceram Glaze Paste, and Amber Ceram G7 Glaze Paste were applied and fired to a uniform thickness on the surface of the specimen. CIE L * , a * , b * values were measured using a spectrophotometer and contrast and translucency were calculated. The bonding interface with the glaze layer was observed using HR FE-SEM. In the glazed groups, L * value increased, but a * value and b * value decreased. The translucency value measured in the untreated group was statically higher in the AMD groups than in UTML groups (P0.05), but significantly decreased compared to the untreated group after glazing treatment in the AMD group (P<0.05). The contrast ratios generally increased after glaze treatment compared to the untreated group. Since the glaze treatment can affect the optical properties of ceramic restorations, the choice of glaze should be considered important for the desired color by the dental technician.

Effect of the cutting flute of the orthodontic miniscrew on insertion and removal torque / 대한치과재료학회지

The purpose of this study was to evaluate the structural characteristics of the thread length of orthodontic mini-screws and the effects of insertion and removal torques according to the formation of the cutting flute. Two types of mini-screws were made, with a thread length of 6.0 mm and a thread length of 3.3 mm. In order to examine the effect of flute formation, the experiment group was divided into a miniscrew test group with flute formation and an experiment group without flute formation. To evaluate the effect of flute formation, two flutes were formed at 180°on the circumference, and at the tip of the mini screw, up to 4 mm for thread length of 6.0 mm and 2.4 mm for thread length of 3.3 mm. A biomechanical test block formed of 2 mm cortical bone and 10 mm cancellous bone was used to eliminate the influence of the difference in cortical bone thickness and bone density according to the insertion site. 1 mm diameter guide hole was drilled on the test block and the mini-screw was placed vertically. Using a 0.1 N·cm precision digital torque gauge, the maximum torque value was recorded at this time by embedding it to the top of the screw under a static load of 1.2 kg and the value when it was removed in the opposite direction. The insertion torque values for the 6.0 mm and 3.3 mm length mini screws were (29.53±1.84) N·cm and (26.84±2.15) N·cm, and the removal torque values are (14.50±1.37) N·cm and (13.15±2.89) N·cm, respectively.There were no statistically significant differences (P>0.05). The flute of 6.0 mm mini-screws had no statistically significant difference in both insertion and removal torque values and increased to (30.13±1.97) N·cm and (18.65±1.10) N·cm (P>0.05). In experiments with 3.3 mm mini-screws, the insertion and removal torque values decreased to (20.99±3.94) N·cm and (11.32±2.03) N·cm, respectively, showing a statistically significant decrease only in the insertion torque values (P<0.05). The insertion and removal torque values of the mini-screw were not significantly increased even when the screw length was doubled, and the flute formation effect was different with the screw length.

Analysis of 1H Magnetic Resonance Spectroscopy Pattern in Invasive Ductal Carcinoma of Breast / 의학물리

To evaluate the potential value of 1H Magnetic resonance spectroscopy (MRS) for detecting and characterizing invasive ductal carcinoma of breast. We conducted 1H Magnetic resonance spectroscopy (MRS), using a 3.0T MR scanner, on 40 patients who were histologically diagnosed to have invasive ductal carcinoma (IDC); tumor areas of the patients were designated as experimental samples, and non-tumor areas as control samples. The peak at 3.2 ppm is characteristically intense and observed in 34 cases of the total 40 invasive ductal carcinoma (sensitivity 86.2%; specificity 100%; positive predictive value 100%; negative predictive value 60%). In constrast peak at 1.3 ppm is characteristically intense and observed in normal breast (sensitivity 86.2%; specificity 100%; positive predictive value 100%; negative predictive value 60%). The study shows that 1H MRS can effectively discriminate invasive ductal carcinoma from normal breast in most cases. It also demonstrates the feasibility of localized in vivo 1H MRS technique as a new diagnostic modality in the detection of breast tumor.

SNR and ADC Changes at Increasing b Values among Patients with Lumbar Vertebral Compression Fracture on 1.5T MR Diffusion Weighted Images / 의학물리

To examine among patients with vertebral compression fracture the extent to which signal-to-noise ratio (SNR) and Apparent Diffusion Coefficient (ADC) values at the lumbar vertebral compression fracture site vary on diffusion-weighted MR images according to varying b values on the 1.5T MR device. Diffusion-weighted MR images of 30 patients with compression fracture due to chronic osteoporosis who underwent vertebral MRI from Jan. 2008 to Nov. 2009 were respectively obtained using a 1.5-T MR scanner with the b values increased from 400, 600, 800, 1,000 to 1,200 s/mm2. For diffusion-weighted MR images with different b values, the signal-to-noise ratio (SNR) was assessed at three sites: the site of compression fracture of the lumbar vertebral body at L1 to L5, and both the upper and lower discs of the said fracture site, while for ADC map images with different b values, the SNR and ADC were respectively assessed at those three sites. As a quantitative analysis, diffusion-weighted MR images and ADC map images with b value of 400 s/mm2 (the base b values) were respectively compared with the corresponding images with each different b value. As far as qualitative analysis is concerned, for both diffusion-weighted MR and ADC map images with b value of 400 s/mm2, the extent to which signal intensity values obtained at the site of compression fracture of the lumbar vertebral body at L1 to L5 vary according to the increasing b values were examined. The quantitative analysis found that for both diffusion-weighted MR and ADC map images, as the b values increased, the SNR were relatively lowered at all the three sites, compared to the base b value. Also, it was found that as the b values increased, ADC values were relatively lowered at all the three sites on ADC map images. On the other hand, the qualitative analysis found that as the b values increased to more than 400 s/mm2, the signal intensity gradually decreased at all the sites, while at the levels of more than 1,000 s/mm2, severe image noises appeared at all of the three sites. In addition, higher signal intensity was found at the site of compression fracture of the lumbar vertebral body than at the discs. Findings showed that with the b value being increased, both the signal-to-noise ratio (SNR) and Apparent Diffusion Coefficient (ADC) values gradually decreased at all the sites of the lumbar vertebral compression fracture and both the upper and lower discs of the fracture site, suggesting that there is a possibility of a wider range of applications to assessment of various vertebral pathologies by utilizing multi b values in the diffusion-weighted MRI examination.

A Study on Usefulness of Specific Agents with Liver Disease at MRI Imaging: Comparison with Ferucarbotran and Gd-EOB-DTPA Contrast Agents / 의학물리

The purpose of this experiment is to know the relation of the detection and characterization of liver's diseases as comparison of finding at MR imaging using a Ferucarbotran (SPIO) and Gd-EOB-DTPA (Primovist) agents in diffuse liver disease. A total of 50 patients (25 men and 25 women, mean age: 50 years) with liver diseases were investigated at 3.0T machine (GE, General Electric Medical System, Excite HD) "with 8 Ch body coil for comparison of diseases and contrast's uptake relation, which used the LAVA, MGRE." All images were performed on the same location with before and after Ferucarbotran and Gd-EOB-DTPA administrations (p<0.05). Contrast to noise ratio of Ferucarbotran and Gd-EOB-DTPA in the HCC were 3.08+/-0.12 and 7.00+/-0.27 with MGRE and LAVA pulse sequence, 3.62+/-0.13 and 2.60+/-0.23 in the hyper-plastic nodule, 1.70+/-0.09 and 2.60+/-0.23 in the meta, 2.12+/-0.28 and 5.86+/-0.28 in the FNH, 4.45+/-0.28 and 1.73+/-0.02 in the abscess and ANOVA test was used to evaluate the diagnostic performance of each disease (p<0.05). In conclusions, two techniques were well demonstrated with the relation of the detection and characterization of liver's diseases.

A Study on Compensation for Imaging Qualities Having Artifact with the Change of the Center Frequency Adjustment and Transmission Gain Values at 1.5 Tesla MRI / 의학물리

The purpose of this study is to compensate for susceptibility and a ferromagnetic body artifact using CFA and TGV on MR Imaging. A total of 30 patients (15 men and 15 women, mean age: 45 years) were performed on head and neck diseases. MR Unit used a 1.5T superconducting magnet (GE medical system, High Density). This study have investigated by changing with CFA and TGV (70, 90, 110, 130, 150) searching for compensation values about susceptibility and a ferromagnetic body artifact in 60 kg standards of body weight (p<0.05). As a quality results, Image qualities were obtained at different score from CFA and TGV (70, 90, 110, 130, 150=3.23+/-0.35, 4.31+/-0.02 4.23+/-0.21, 5.12+/-0.25, 7.13+/-0.72, 8.31+/-0.01, 5.21+/-0.15, 6.14+/-0.08, 5.23+/-0.72, 5.91+/-0.06, p<0.05). Absolute CNRs (TG, CNRpre, CNRpost) were acquired with (70:-1.44+/-0.11, -2.7+/-0.04, 90:-2.18+/-0.42, -4.41+/-0.43, 110:-2.89+/-0.43, -5.23+/-0.02, 130:-2.34+/-0.05, -5.26+/-0.01, 150: -2.09+/-0.08, -3.87+/-0.12, p<0.05). In conclusions, this study could be compensated for metal and flow artifacts surrounding the tissues having artifact by changing CFA and TGV.

MR T2 Map Technique: How to Assess Changes in Cartilage of Patients with Osteoarthritis of the Knee / 의학물리

By using the MR T2 map technique, this study intends, first, to measure the change of T2 values of cartilage between healthy people and patients with osteoarthritis and, second, to assess the form and the damage of cartilage in the knee-joint, through which this study would consider the utility of the T2 map technique. Thirty healthy people were selected based on their clinical history and current status and another thirty patients with osteoarthritis of the knee who were screened by simple X-ray from November 2007 to December 2008 were selected. Their T2 Spin Echo (SE hereafter) images for the cartilage of the knee joint were collected by using the T2 SE sequence, one of the multi-echo methods (TR: 1,000 ms; TE values: 6.5, 13, 19.5, 26, 32.5. 40, 45.5, 52). Based on these images, the changes in the signal intensity (SI hereafter) for each section of the cartilage of the knee joint were measured, which yielded average values of T2 through the Origin 7.0 Professional (Northampton, MA 01060 USA). With these T2s, the independent samples T-test was performed by SPSS Window version 12.0 to run the quantitative analysis and to test the statistical significance between the healthy group and the patient group. Closely looking at T2 values for each anterior and lateral articular cartilage of the sagittal plane and the coronal plane, in the sagittal plane, the average T2 of the femoral cartilage in the patient group with arthritis of the knee (42.22+/-2.91) was higher than the average T2 of the healthy group (36.26+/-5.01). Also, the average T2 of the tibial cartilage in the patient group (43.83+/-1.43) was higher than the average T2 in the healthy group (36.45+/-3.15). In the case of the coronal plane, the average T2 of the medial femoral cartilage in the patient group (45.65+/-7.10) was higher than the healthy group (36.49+/-8.41) and so did the average T2 of the anterior tibial cartilage (i.e., 44.46+/-3.44 for the patient group vs. 37.61+/-1.97 for the healthy group). As for the lateral femoral cartilage in the coronal plane, the patient group displayed the higher T2 (43.41+/-4.99) than the healthy group did (37.64+/-4.02) and this tendency was similar in the lateral tibial cartilage (i.e., 43.78+/-8.08 for the patient group vs. 36.62+/-7.81 for the healthy group). Along with the morphological MR imaging technique previously used, the T2 map technique seems to help patients with cartilage problems, in particular, those with the arthritis of the knee for early diagnosis by quantitatively analyzing the structural and functional changes of the cartilage.

The Role of Plasma Endothelin-1 in Fluid-Electrolyte Balance and Renal Function in Patients with Liver Cirrhosis / 대한내과학회지

OBJECTIVES: It has been recently known that endotheUn-1 is a potent vasoconstrictor. The purpose of the present study was to clarify the possible correlation of endothelin-1 with other vasoactive neurohormonal activities and its effects on fluid-electrolyte balance and renal function in patients with liver cirrhosis. METHODS: In 35 patients of liver cirrhosis with (n=19) and without (n=16) ascites and in 12 normal controls, plasma and urine levels of endothelin-1 were measured by specific radioimmunoassay, and serum sodium, serum albumin and other blood chemistries, renal functions with creatinine clearance, urinary sodium excretion, plasma renin activity, plasma aldosterone and plasma norepinephrine were measured at the same time. RESULTS: The plasma endothelin-1 level was significantly higher in ascitic group than nonascitic group (mean +/- SD; 16.4 +/- 10.6 VS. 7.5 +/- 4.1pg/mL, p=0.0000), and there was no significant difference in plasma endothelin-1 level between nonascitic group and normal controls(4.8 +/- 1.9pg/mL). The urine endothelin-1 level also was significantly higher in ascitic group than non-ascitic group (140.3 +/- 74.3 VS. 58.5 +/- 37.4 pg/mL, p=0.0000), there was no significant difference in urine endothelin-1 level between nonascitic group and normal controls (19.5 +/- 112pg/mL). In patients with cirrhosis, the plasma endothelin-1 concentration showed significant negative correlation with creatinine clearance (r=-0.55), serum albumin (r=-0.56%) and serum sodium concentrtion (r=-0.62), and significant positive correlation with plasma renin activity (r=0.63), plasma aldosterone (r=0.68) and norepinephrine (r=0.70). The factors that influence on plasma concentration of endothelin-1 were plasma norepinephrine (p=0.0000), serum sodium (p=0.0169), plasma aldosterone (p=0.0176), serum albumin (p=0.0213) and plasma renin activity (p=0.0329) in statistically significant order. CONCLUSION: The elevated plasma endothelin-1 level along with the increased activity of other neurohormonal substances including plasma renin, aldosterone and norepinephrine induces sodium and water retention in decompensated liver cirrhosis. Thus, the plasma endothelin-1 level seems to have an important role in the development of functional renal impairment in decompensated liver cirrhosis by inducing renal vasoconstriction.

Changes in Plasma Dehydroepiandrosterone-Sulfate ( DHEA-S ) Level & DHEA-S / cortisol Ratio by Age in Healthy Korean / 대한내분비학회지

BACKGROUND: DHEA-S is the most abundant steroid hormone in circulation, and primarily secreted from the adrenal cortex, but its physiological role is little known. One of the characteristic features of DHEA-S is progressive decrement of plasma DHEA-S level with advancing age, in contrast, plasma levels of other adrenal hormones are not chaging or littie decreasing. To grasp the trends of plasma DHEA-S level and DHEA-S/cortisol ratio by age in healthy Korean, we measured the plasma DHEA-S levels and DHEA-S/cortisol ratios in healthy Korean. METHODS: Healthy Korean (men: 99, women: 102, age range: 15-97 year old)were studied. Subjects were not taking drugs (such as glucocorticoid or androgenic medication) or cigarettes known to modify the plasma level of DHEA-S and cortisol, and had no evidence of hepatic, renal disease or hyperlipidemia as determined by serum lipid, bilirubin, SGOT, SGPT, BUN, creatinine. Data were analyzed by 10-year age group for men and women: i.e, 10-19, 20-29, 30-39, 40-49, 50-59, 60-69, 70-79, 80-89 and 90 year or more. Plasma DHEA-S levels were measured by using a commercially available RIA kit with 125I labeled-DHEA-SO4 (Coat-A Count DHEA-SO4), and for the measurement of plasma cortisol levels, commercial Gamma Coat TM[125I] Cortisol Radioimmunassay Kit was used. RESULTS:. 1) In both men and women, plasma DHEA-S level showed high interindividual variation within the same age group. 2) There were individual sex differences in plasma levels of DHEA-S, in all age groups, plasma DHEA-S levels were significantly higher values for men than for women. 3) Maximum plasma DHEA-S levels (men; 237+-3.35 ug/dL, women; 108+-17.5 ug/dL) were at third decade in both men and women. 4) Both men and women showed the continuous decline in plasma DHEA-S level with age. These age-related decline was more prominent in men than in women (men; y=-3.152 * +292.6, r2= 0.8459, P<0.05, women; y= -1.417 * +143.3, r2 = 0.7278, P< 0.05). 5) As an index of aging, there was no stastical difference between DHEA-S and DHEA-S/cortisol ratio. CONCLUSION: In healthy Korean, there were high interindividual variation of plasrna DHEA-S levels. In both men and women plasma DHEA-S level was peak at third decade, and from when it declined progressively with age. These results suggest that although the reliability of single plasma DHEA-S measurement are limited, the decline of DHEA-S with advancing age might be a specific marker of endocrinologic hormonal milieu (aging index). Also, concerning to individual adrenal secreting capacity, we measured DHEA-S/cortisol ratio. But we did not found that plasma DHEA-S/cortisol ratio is superior to the plasma DHEA-S level as an aging index.