Although ceramic brackets have been used widely for improved esthetics during treatment, ceramic brackets have some inherent problems; brittleness, attrition of the opposing teeth and high frictional resistance. This study was performed to understand the frictional resistance of the ceramic brackets, as well as to be a helpful reference for finding the solutions to the problem of frictional resistance. Three different kinds of brackets were used; metal bracket, polycrystalline ceramic brackets with a metal slot to reduce the high frictional resistance and monocrystalline ceramic brackets. The brackets were tested with a .019 x .025 stainless steel wire with a second order angulation of 0 degrees and 10 degrees, and the static and kinetic frictional forces were measured on the universal testing machine. The results of this study showed that the ceramic brackets, especially the monocrystalline ceramic bracket without a metal slot, generated higher frictional resistance than the metal bracket, and the frictional resistance was increased as the angulation between the bracket slot and the wire increased. Therefore, the development of the ceramic bracket with reduced frictional resistance and the prevention of excessive crown tipping during orthodontic treatment will lead to the simultaneous attainment of more efficient and improved esthetic treatment goals.
Ceramics* ; Crowns ; Esthetics ; Friction* ; Stainless Steel ; Tooth

OBJECTIVE: The purpose of this study was to investigate the stability of mini-implants in relation to loading time. METHODS: A total of 48 mini-implants (ORLUS, Ortholution, Korea) were placed into the buccal alveolar bone of the mandible in 8 male beagle dogs. Orthodontic force (200 - 250 gm) was applied immediately for the immediate loading group while force application was delayed for 3 weeks in the delayed loading group. For the subsequent loading periods (3, 6, 12 weeks), BIC (bone implant contact) and BV/TV (bone volume/total volume) and mobility test were carried out. RESULTS: The immediate loading group showed no changes in BIC from 3 to 12 weeks, while the delayed loading group showed a significant increase in BIC between 3 and 12 weeks (p < 0.05). The BV/TV of the delayed loading group significantly increased from 6 to 12 weeks of loading (p < 0.05), while the BV/TV of the immediate loading group decreased from 3 to 12 weeks of loading. However, there was no significant difference in BV/TV between experimental groups. The mobility of the immediate loading group was not significantly different from that of the delayed loading group after 12 weeks of loading (p < 0.05). CONCLUSIONS: These results showed that immediate loading does not have a negative effect on the stability of mini-implants compared to the early loading method in both the clinical and histomorphometric point of view.
Animals ; Dogs ; Humans ; Male ; Mandible ; Nitrogen Mustard Compounds

OBJECTIVE: Miniscrew-assisted rapid palatal expansion (MARPE) is a means for expanding the basal bone without surgical intervention in young adults. Here, we assessed the differences in dental, alveolar, and skeletal measurements taken before (T0), immediately after (T1), and 1 year after (T2) MARPE. METHODS: Twenty-four patients (mean age, 21.6 years) who had undergone MARPE and cone-beam computed tomography at T0, T1, and T2 were included. Changes in the following parameters were compared using paired t-tests: intercusp, interapex, alveolar, nasal floor, and nasal cavity widths; inclination of the first molar (M1) and its alveolus; and thickness and height of the alveolar bone. A linear mixed-effects model was used to determine variables that affected periodontal changes in the M1. RESULTS: MARPE produced significant increases in most measurements during T0–T2, despite relapse of some measurements during T1–T2. The alveolar thickness decreased on the buccal side, but increased on the palatal side. The alveolar crest level at the first premolar moved apically. Changes in the thickness and height of the alveolar bone were affected by the corresponding initial values. CONCLUSIONS: MARPE can be used as an effective tool for correcting maxillomandibular transverse discrepancy, showing stable outcomes 1 year after expansion.
Bicuspid ; Cone-Beam Computed Tomography ; Humans ; Molar ; Nasal Cavity ; Recurrence ; Young Adult

BACKGROUND: The intravenous injection of rocuronium bromide is often painful, and different methods have been used to minimize the incidence and severity of this pain. This study determined the effective dose of alfentanil to minimize the injection pain of rocuronium and the cardiovascular response after endotracheal intubation. METHODS: Eighty ASA physical status 1 and 2 adult patients were divided into four groups. Sixty seconds before administering rocuronium 0.6 mg/kg, the groups were given 10 ml of intravenous normal saline or alfentanil 10, 15, and 20microgram/kg. Pain was assessed after rocuronium injection. The mean arterial pressure and heart rate were measured before induction and before and after intubation. RESULTS: Both 15 and 20microgram/kg alfentanil minimized the rocuronium injection pain, although 20microgram/kg alfentanil caused an undesirable decrease in the mean arterial pressure. CONCLUSIONS: A 15microgram/kg bolus of alfentanil may be useful for minimizing the rocuronium injection pain and blunting the cardiovascular response after endotracheal intubation.
Adult ; Alfentanil ; Androstanols ; Arterial Pressure ; Heart Rate ; Humans ; Incidence ; Injections, Intravenous ; Intubation, Intratracheal

No abstract available.
Heart* ; Tomography, Emission-Computed, Single-Photon*

OBJECTIVE: To analyze the clinical characteristics of Korean pediatric, adolescent and premarital women who visited the Adolescent Gynecology Clinic at Samsung Medical Center. METHODS: A retrospective study was performed on the 2070 women visiting the Adolescent Gynecology Clinic at Samsung Medical Center from Feb. 1995 to Sep. 2003. The patients were divided into 3 groups according to patients' age; group I (~9 years, 258 patients), group II (10-20 years, 911 patients), group III (21-30 years, 901 patients). Clinical characteristics were analyzed by chart review and compared among three groups. RESULTS: The mean patient age was 18.4 +/- 6.9 years (mean SD) and the mean age at menarche was 13.4 +/- 1.5 years. The most common disease entity and disorder according to age groups were infectious disease and vaginitis in group I, menstruation associated problems and abnormal uterine bleeding (AUB) in group II, and menstruation associated problems and amenorrhea in group III. Among gynecologic problems, AUB was cited as the most common problem for the patients visiting the Adolescent Gynecology Clinic (425 cases, 20.5%), followed by amenorrhea (393 patients, 19.0%). 51.0% of primary amenorrhea had a congenital defects. Among the patients with pelvic tumor (293 patients), 85.3% was due to ovarian tumor, and 166 patients (66.4%) with ovarian tumor underwent operation. The most common pathologic diagnosis for ovarian tumor was endometrioma (60 cases, 36.1%). In primary dysmenorrhea (214 patients, 76.2% of total dysmenorrhea), treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) resulted in symptomatic improvement in 82.6% of the patients. The most common infectious disease was vaginitis and the most commonly isolated organisms varied according to age group (group I, II: E. coli, group III: Candida albicans). CONCLUSION: The most common gynecologic problem in korean pediatric, adolescent and premarital women is menstruation related disorders, presenting in 58.8% of patients visiting the Adolescent Gynecology Clinic.
Adolescent* ; Amenorrhea ; Candida ; Communicable Diseases ; Congenital Abnormalities ; Diagnosis ; Dysmenorrhea ; Endometriosis ; Female ; Gynecology* ; Humans ; Menarche ; Menstruation ; Retrospective Studies ; Uterine Hemorrhage ; Vaginitis

This is a case report about benign metastasizing leiomyoma with multiple lymph node metastasis. A 34-year-old woman received an abdominal myomectomy for a suspicious leiomyoma. On the pathology report, atypical leiomyoma was suspected. Due to the suspicion of multiple lymph node metastasis on pelvis computed tomography (CT) 1 year after the operation, she was transferred to the Samsung Medical Center on October, 2009 for further work up. According to original slide review, it was determined to be a benign leiomyoma with a mitotic count <5/10 high-power fields, little cytological atypia and no tumor cell necrosis. Additional immunostaining was done. Multiple lymph node metastasis and a small lung nodule were identified on positron emission tomogarphy-CT and chest CT. Extensive debulking surgery and diagnostic video-assisted thoracoscopic surgery (VATS) wedge resection were subsequently done. Metastatic lesions were reported to have a histology similar to that of the original mass. VATS right upper lobectomy with mediastinal lymph node dissection was performed because of the pathology result of VATS (adenocarcinoma). She started taking an aromatase inhibitor (Letrozole(R)) and there was no evidence of recurrence of disease on an imaging study and no post-operative complications until recently.
Adult ; Aromatase ; Electrons ; Female ; Humans ; Leiomyoma ; Lung ; Lymph Node Excision ; Lymph Nodes ; Lymphatic Metastasis ; Necrosis ; Neoplasm Metastasis ; Pelvis ; Recurrence ; Thoracic Surgery, Video-Assisted ; Thorax

OBJECTIVE: The aim of this study was to evaluate the skeletal and dentoalveolar changes after miniscrew-assisted rapid palatal expansion (MARPE) in young adults by cone-beam computed tomography (CBCT). METHODS: This retrospective study included 14 patients (mean age, 20.1 years; range, 16–26 years) with maxillary transverse deficiency treated with MARPE. Skeletal and dentoalveolar changes were evaluated using CBCT images acquired before and after expansion. Statistical analyses were performed using paired t-test or Wilcoxon signed-rank test according to normality of the data. RESULTS: The midpalatal suture was separated, and the maxilla exhibited statistically significant lateral movement (p < 0.05) after MARPE. Some of the landmarks had shifted forwards or upwards by a clinically irrelevant distance of less than 1 mm. The amount of expansion decreased in the superior direction, with values of 5.5, 3.2, 2.0, and 0.8 mm at the crown, cementoenamel junction, maxillary basal bone, and zygomatic arch levels, respectively (p < 0.05). The buccal bone thickness and height of the alveolar crest had decreased by 0.6–1.1 mm and 1.7–2.2 mm, respectively, with the premolars and molars exhibiting buccal tipping of 1.1°–2.9°. CONCLUSIONS: Our results indicate that MARPE is an effective method for the correction of maxillary transverse deficiency without surgery in young adults.
Adult ; Bicuspid ; Cone-Beam Computed Tomography* ; Crowns ; Humans ; Maxilla ; Methods ; Molar ; Retrospective Studies ; Sutures ; Tooth Cervix ; Young Adult* ; Zygoma