• The korean journal of orthodontics
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• v.28 no.5 s.70
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• pp.717-729
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• 1998

This study was done to estimate arch forms and dimensions at the bracket level where archwire was placed in Angle's Class I first premolars extraction cases. 60 post-treatment dental casts which had attained good orthodontic treatment results were used in this study Many landmarks and linear measurement items to describe arch forms and dimensions were determined and measured. With a computer system and digitizer, arch forms were described and linear measurement items were statistically analysed. The following results were obtained. 1. The average labial and lingual arch forms at the bracket level were obtained. 2. Arch forms were expressed by parabolic equations and coefficients of determination. 3. Arch widths were larger in male than in female. 4. There were statistical significances in upper intercanine width, upper interfirst molar width, upper intersecond molar height, lower intercanine width and lower interfirst molar width between both sexes (p<0.05, p<0.01). 5. Interfirst molar width differences between maxilla and mandible were 6.43mm in male and 6.05mm in female.

• Biomedical Science Letters
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• v.16 no.1
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• pp.68-70
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• 2010

Puer tea is a traditional beverage originating from Yunnam area of China. It supplies basic nutrients such as vitamin C. It has been well reported that daily drinking of Puer tea can help the digestion and ease the stomachache after food intake. Puer tea also contains various polyphenols which may exert antibacterial activity against Staphylococcus aureus and Listeria monocytogenes. Because of these functional effects on digestive system we suspected if Puer tea can display any dietary effect or decrease the obesity after long-term drinking. We employed 6-week old SD rats as experimental animal and treated them with extract of Puer tea in relation to the body weights. Rats were divided into 5 groups (NC, PC, E, E+P, E+P5). NC group was experimental control and rest of them are as follows: water only (PC), water with exercise (E), water with exercise and Puer tea extract (E+P), water with exercise and 5X extract of Puer tea (E+P5). Feeding was carried out every day for 5 weeks by oral administration. Reduction rate of body weights was highest in E group. Relative ratio of losing weight was as follows: PC group (100.78%), E group (95.57%), E+P group (94.53%) and E+P5 group (74.22%), respectively. Exercise was more helpful to control the body weight. The result strongly suggests that Puer tea is highly effective to control the body weight and could be used for pharmaceutical purpose to treat obesity without side effects.

• Restorative Dentistry and Endodontics
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• v.33 no.6
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• pp.499-506
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• 2008

The purpose of this study was to compare the push-out strength of a fiber post cemented with various resin cements. Newly extracted 36 human mandibular premolars which had single root canal were selected and their crown portions were removed. The root canal was instrumented using $PROTAPER^{TM}$ system and obturated using continuous wave technique. In each root, a 9-mm deep post space was prepared. #2 translucent fiber post (DT Light post, Bisco Inc., Schaumburg, IL, U.S.A.) was cemented using injection technique with Uni-dose needle tip (Bisco) and six different resin cements. The tested resin cements were Duo-Link (Bisco Inc., Schaumburg, IL, U.S.A.), Variolink II (Ivoclar-Vivadent AG, Schann, Liechtenstein), Panavia F (Kuraray Medical Inc., Okayama, Japan), Multilink Automix (Ivoclar-Vivadent AG, Schann, Liechtenstein), RelyX Unicem (3M ESPE Dental Products, St. Paul, MN, U.S.A.), and Maxcem (Kerr Co., CA, U.S.A.). After storage in distilled water for 24 hours, each root was transversally sectioned into approximately 1-mm thick sections. This procedure resulted in 6 serial sections per root. Push-out test wasperformed using a universal testing machine (EZ Test, Shimadzu Co.) with a crosshead speed of 1 mm/min. The data were analyzed with one-way ANOVA and Tukey HSD (p=0.05). The push-out strength of the groups which cemented fiber post with Panavia F and Multilink Automix were lower than those of the other groups. But, there were no statistically significant difference among groups at a probability level of 0.05.

• The korean journal of orthodontics
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• v.38 no.6
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• pp.427-436
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• 2008

Objective: The purpose of this study is to compare landmark position between cephalometric radiography and midsagittal plane projected images from 3 dimensional (3D) CT. Methods: Cephalometric radiographs and CT scans were taken from 20 patients for treatment of mandibular prognathism. After selection of land-marks, CT images were projected to the midsagittal plane and magnified to 110% according to the magnifying power of radiographs. These 2 images were superimposed with frontal and occipital bone. Common coordinate system was established on the base of FH plane. The coordinate value of each landmark was compared by paired t test and mean and standard deviation of difference was calculated. Results: The difference was from $-0.14{\pm}0.65$ to $-2.12{\pm}2.89\;mm$ in X axis, from $0.34{\pm}0.78$ to $-2.36{\pm}2.55\;mm$ ($6.79{\pm}3.04\;mm$) in Y axis. There was no significant difference only 9 in X axis, and 7 in Y axis out of 20 landmarks. This might be caused by error from the difference of head positioning, by masking the subtle end structures, identification error from the superimposition and error from the different definition.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.361-376
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• 1995

The purpose of this study was to investigate the relationship between the head and neck postre and the cervical curvature, especially in forward head postrue(FHP). Sixty patients with craniomandibular disorders and thirty dental students without any signs and symptoms of craniomandibular disordres participated in this study as patient groups and sa control group, respectively. The author evaluated the head and neck posture of all subjects by plumb line and CROM( Cervical Ragne of Motion), and had taken cephaograph in natural head position. On the cephalograph the angle of cervical inclination formed by true horizntal plane and 4th cervical vertebra(C4) and the radius of cervical curvature from C1 to C5 were measured. A specially designed ruler was used for measuring cervical curvature. Occlusal contac number and force with T-scan system, electromygraphic activity of cervical muscles with Bio-EMG, and distance of freeway space with Bio-ECN were recorded, respectively. The collected data were processed by SAS/STAT progrm. The obtained results were as follows : 1. In subjects with longer radius which was less cervical curvature, head positioned more anteriorly than subjects with smaller radius, and they showed slightly straight cervical vertebra. 2. Between the patients and the control group, there were no differences in cervical curvature, in forward head position by plumb line and in CROM. But the patient group had a greater cervical inclination than the control group had. 3. There were positive correlation between cervical curvature and forward head position by plumbline,between forward head position y plumb line and that by CROM in patient group. The cervical inclination, however, had negative correlation with cervical curvature, and with forward head postion by plumb line, respectively. 4. In case of showing more cervical curvature and more forward head position by plumb line the head position was defined as forward head posture. In patient group, subjects without forward head posture showed greater posterior teeth contact force than subjects with forward head posture, but in control group, there were no difference between the two subjects. 5. There were higher electromyographic activity in almost all muscles and smaller freeway space in induced forward head posture than those in natural head position in subjects without forward head posture. In conclusion, head position of patients with craniomandibular disorders were not more anterior than that of normal control person, but they had tendency to head extension. From the result of this study, forward head posture could be defined as posterior rotation of upper cervical segment with a straight lower cercial segment due to loss of normal lordosis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.6
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• pp.628-635
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• 2000

The purpose of this study was to evaluate the result after 2-phase surgical-orthodontic treatment without preoperative orthodontic treatment for the skeletal Cl III malocclusion patient and to obtain an adequate protocol on the bases of this result. This retrospective study of ten patients who underwent 2-phase treatment were done to evaluate 1) the surgical stability and relapse pattern 2) the facial esthetics 3) the TMJ problem 4) the total time of the treatment. Results were followed : 1) The horizontal relapse of the mandible was 26.8% and didn't show significant differences compared to the conventional 3-phase treatment. But, it was considered that this amount of relapse was the sum of true relapse and autoratation of mandible due to decreased vertical dimension during orthodontic treatment. 2) It was estimated that there's no difference on the ratio of anterior facial height between the subjects and the normal patients. On the horizontal analysis, the mandible of the subjects was located more anteriorly than that of the normal patients. This result showed that there was a need for the accurate preoperative esthetic evaluation and the additional methods for reducing the relapse due to the occlusal interference. 3) Wide variation was noted on the TMJ symptoms of the subjects, however, it was estimated that there's no significant differencees of symptoms compared to that of the conventional 3-phase treatment on literatures. 4) The average of the overall period of treatment was 20.8 months and we obtained reduction of the treatment time compaired to 3-phase treatment on many literatures. Most of the results of this study were similar to the findings of the 3-phase treatment(preoperative orthodontic-orthognathic surgery-postoperative orthodontic), but total time of the treatment was shorter in patients with 2-phase treatment than in those with the conventional 3-phase treatment. With 2-phase treatment, we experienced many advantages compared to the conventional method considering that it was favarable conditions for the teeth, it had the flexibility for the treatment, and it could be the adequate treatment approach for the stomatognathic system. Although this retrospective pilot study had some limitations, due to small samples, the authors would hope that it could serve as a guide for the future researches, and the clinical applications.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.4
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• pp.662-670
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• 2008

The purpose of this in vitro study was to evaluate the effect of fluoride containing adhesive film on prevention of enamel demineralization. Eighty bovine enamel blocks were divided randomly into 4 groups of 25: (1) APF gel applied ; (2) CavityShield$^{TM}$ applied; (3) 3% fluoride film applied; (4) 5% fluoride film applied; Early caries lesions were produced by placing each specimen into demineralization solution at pH 4.0 for 72 hours. Then lesion of the surface microhardness were measured by the Vicke's hardness test and the lesions depth were measured by polarizing light microscope. The results of the present study are as follows: 1. Difference of microhardness value ($M{\pm}SD$) between control and experimental side was the highest in group II, followed by group IV, III, I but, no significant difference was between group II, III and IV. 2. Difference of mean lesion depth ($M{\pm}SD$) between control and experimental side was the highest in group II, followed by group III, IV and I but no significant difference was between group III and IV. The results of the present study indicate that the fluoride film application is more effective than APF gel and is similar to fluoride varnish application for prevention of dental caries.

• Child Health Nursing Research
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• v.19 no.3
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• pp.159-167
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• 2013

Purpose: The purpose of this study is to find out preschool children's health status and their mothers' health management in the vulnerable classes. Methods: The assessment tool was developed, taken into consideration existing studies, materials produced by the customized visiting health care system, and review of visiting nurses of health centers and related experts. Data were collected January to February 2010 from 259 mothers by visiting nurses, and analyzed using SAS program for descriptive statistics. Results: Body weight less than 3 percentile was found for 5.0% children and over 97 percentile for 7.7%. Atopy was found in 17.8% children, no hand-washing after toileting and before meal in 30.9% and 36.7% respectively, no breakfast in 15.8%, and irregular meal in 32.0%. Sex education was made by 45.7% mothers, regular dental check by 56.6%, and hearing and eyesight test by 61.1% and 66.8% respectively. Home environment for upbringing is 34.3 in the scale of 41, and accident prevention 17.5 in the scale of 22. Conclusion: It is necessary to make an intervention on children's weight, personal sanitation and meal time in the vulnerable classes. Mothers need to be educated for appropriate health care, and home environments to improve upbringing and accident prevention.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.2
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• pp.203-211
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• 2008

Minimizing damage to anatomical structure is a prerequisite for skeletal anchorage system to install a miniscrew. This research has focused on evaluating the stability and safety of installation in the maxillary molar buccal area, in which most miniscrews are installed clinically and initial fixation is weak. CT (computerized tomography)images were taken for surveying the possibility of damaging to adjucent teeth in accordance with installation angle. If we install a mini-screw($1.2{\times}6.0mm$) in the maxillary molar buccal area, it would be located generally in the 5~8mm upper of CEJ and 3~5mm inner of the cortical bone surface. We has measured the space between roots And comparison has been made for gender and the space between roots in accordance with the 3 different angles of installation(30 degree, 40 degree, 60 degree) in 3 categories. Category 1 : between 1st molar and 2nd molar Category 2 : between 1st molar and 2nd premolar Category 3 : between 1st premolar and 2nd premolar The result are as follow; 1. The space for category 1 was significantly small. 2. For the installation angle, it was safer to install with steeper angle in category 1 and category 2, but not in category 3. According to these results, the installation a miniscrew in category 2, 3 is safer than in category 1. And it is safer to install with steeper angle in category 1 and category 2.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.253-264
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• 2010

The purpose of this study is to know whether Yttrium-stabilized-tetragonal -zirconia-polycrystal(Y-TZP ceramic) gets enough shear bond strength for clinical uses by applying veneering composite resin through surface treatment on it and finally to compare it with the case of applying veneering porcelain. LavaTM zirconia frameworks(3M ESPE, Seefeld, Germany) were prepared. Group P was manufactured with LavaTM Ceram(3M ESPE, Seefeld, Germany) in cylindrical shape which has 4mm diameter, 5mm height. Group ZSR disposed sandblasting and applied silane, bonding agent and after that indirect composite resin was applied. Group ZRR got tribochemical coating by RocatecTM system(3M ESPE. Seefeld, Germany) and treated silane. Finally Group ZPR took the same treatment and applied LavaTM Ceram in the size of 0.3-0.5mm height. After burning out, sandblasting, HF and silane was applied. And then, indirect composite resin was applied. 1000 cycle thermocycling was performed in $5-55^{\circ}C$ and shear bond strength was measured. There were no significant differences between combining veneering porcelain to Y-TZP ceramic group and combining veneering resin to Y-TZP ceramic group in the aspect of shear bond strength (p>.05).