No abstract available.
Colitis, Ulcerative* ; Ulcer*

OBJECTIVE: This study was conducted to perform histomorphometric evaluations of the bone surrounding orthodontic miniscrews according to their proximity to the adjacent tooth roots in the posterior mandible of beagle dogs. METHODS: Four male beagle dogs were used for this study. Six orthodontic miniscrews were placed in the interradicular spaces in the posterior mandible of each dog (n = 24). The implanted miniscrews were classified into no loading, immediate loading, and delayed loading groups according to the loading time. At 6 weeks after screw placement, the animals were sacrificed, and tissue blocks including the miniscrews were harvested for histological examinations. After analysis of the histological sections, the miniscrews were categorized into three additional groups according to the root proximity: high root proximity, low root proximity, and safe distance groups. Differences in the bone–implant contact (BIC, %) among the root proximity groups and loading time groups were determined using statistical analyses. RESULTS: No BIC was observed within the bundle bone invaded by the miniscrew threads. Narrowing of the periodontal ligament space was observed in cases where the miniscrew threads touched the bundle bone. BIC (%) was significantly lower in the high root proximity group than in the low root proximity and safe distance groups. However, BIC (%) showed no significant differences among the loading time groups. CONCLUSIONS: Regardless of the loading time, the stability of an orthodontic miniscrew is decreased if it is in contact with the bundle bone as well as the adjacent tooth root.
Animals ; Dogs ; Humans ; Male ; Mandible ; Periodontal Ligament ; Tooth Root

OBJECTIVE: The purpose of this study was to evaluate the mechanical performance of mini-screws during insertion into artificial bone with use of the driving torque tester (Biomaterials Korea, Seoul, Korea), as well as testing of Pull-out Strength (POS). METHODS: Experimental bone blocks with different cortical bone thickness were used as specimens. Three modules of commercially available drill-free type mini-screws (Type A; pure cylindrical type, Biomaterials Korea, Seoul, Korea, Type B; partially cylindrical type, Jeil Medical, Seoul, Korea, Type C; combination type of cylindrical and tapered portions, Ortholution, Seoul, Korea), were used. RESULTS: Difference in the cortical bone thickness had little effect on the maximum insertion torque (MIT) in Type A mini-screws. But in Type B and C, MIT increased as the cortical bone thickness increased. MIT of Type C was highest in all situations, then Type B and Type A in order. Type C showed lower POS than Type A or B in all situations. There were statistically significant correlations between cortical bone thickness and MIT, and POS for each type of the mini-screws. CONCLUSION: Since different screw designs showed different insertion torques with increases in cortical bone thickness, the best suitable screw design should be selected according to the different cortical thicknesses at the implant sites
Biocompatible Materials ; Korea ; Seoul ; Torque*

OBJECTIVE: The aim of this study was to validate the Periotest values for the prediction of orthodontic mini-implants' stability. METHODS: Sixty orthodontic mini-implants (7.0 mm x O1.45 mm; ACR, Biomaterials Korea, Seoul, Korea) were inserted into the buccal alveolar bone of 5 twelve month-old beagle dogs. Insertion torque (IT) and Periotest values (PTV) were measured at the installation procedure, and removal torque (RT) and PTV were recorded after 12 weeks of orthodontic loading. To correlate PTV with variables, the cortical bone thickness (mm) and bone mineral density (BMD) within the cortical bone and total bone area were calculated with the help of CT scanning. RESULTS: The BMD and cortical bone thickness in mandibular alveolus were significantly higher than those of the maxilla (p< 0.05). The PTV values ranged from -3.2 to 4.8 for 12 weeks of loading showing clinically stable mini-implants. PTV at insertion was significantly correlated with IT (-0.51), bone density (-0.48), cortical bone thickness (-0.42) (p< 0.05) in the mandible, but showed no correlation in the maxilla. PTV before removal was significantly correlated with RT (-0.66) (p< 0.01) in the mandible. CONCLUSIONS: These results show that the periotest is a useful method for the evaluation of mini-implant stability, but it can only be applied to limited areas with thick cortical and high density bone such as the mandible.
Animals ; Biocompatible Materials ; Bone Density ; Dogs ; Korea ; Mandible ; Maxilla ; Torque

No abstract available.
Amylases* ; Child* ; Encephalitis, Arbovirus* ; Humans

No abstract available.
Fetal Weight* ; Humans ; Infant* ; Infant, Low Birth Weight* ; Infant, Newborn ; Parturition* ; Weight Gain*

No abstract available.
Hepacivirus* ; Hepatitis C* ; Hepatitis* ; Liver Diseases* ; Liver* ; Prevalence*

No abstract available.
Antigens, Surface* ; Leukemia*

No abstract available.
Humans ; Twins, Monozygotic*

The purine antimetabolite 6-Mercaptopurine (6-MP) has been in clinical use for over 30 years and is still a widely used agent in the treatment of childhood acute lymphoblastic leukemia. The bioavailibility, clinical efficacy and toxicity of 6-MP administered orally for maintenance therapy of children with acute lymphoblastic leukemia are highly variable in many studies, as well as at differnt times in same patient. there are many factors affecting the bioavailibility of 6-MP. The most notably factor being that concomitantly administered drugs and foods might contribute to a decrease in the bioavailibity of this drug. In our sociocultural environment milk is a major constituent of child's foods. Cow's milk contains a high concentration of xanthine oxidase, which could potentially transform 6-TM into 6-thioxanthine (6-TX) and 6-thiouric acid (6-TUA) which have no more therapeutic effects. In this study, we evaluated the effect of various milk products on the bioavailability of 6-MP. Incubation at 37degrees C for 30 min raw or pasteurized milk resulted in transformation of a large quantity of clinically relevant concentration of 6-MP into 6-TUA. The concomitant adminstration of folic acid and allopurinol has markedly inhibitory effect on the 6-MP destroying activity of milk at clinically relevant concentrations. These observations may help to optimize modalities of administration of 6-MP for the treartment of patients with childhood leukemia.
6-Mercaptopurine* ; Allopurinol ; Biological Availability* ; Child ; Complement Factor B ; Folic Acid ; Humans ; Leukemia ; Milk* ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; Xanthine Oxidase