Effect of extraction treatment on upper airway dimensions in patients with bimaxillary skeletal protrusion relative to their vertical skeletal pattern / 대한치과교정학회지

Objective@#To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes. @*Methods@#Fiftyfive adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness: hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (β = –0.42, p < 0.01) and inferior airway space (β = –0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship. @*Conclusions@#Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

Effect of extraction treatment on upper airway dimensions in patients with bimaxillary skeletal protrusion relative to their vertical skeletal pattern / 대한치과교정학회지

Objective@#To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes. @*Methods@#Fiftyfive adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness: hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (β = –0.42, p < 0.01) and inferior airway space (β = –0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship. @*Conclusions@#Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

Predictors of Progression and Prognosis of Paroxysmal Atrial Fibrillation / 대한내과학회지

BACKGROUND/AIMS: Significant numbers of patients with paroxysmal atrial fibrillation (AF) proceed to persistent AF and have poor clinical outcomes despite the use of antiarrhythmic agents or direct-current cardioversion. We compared the CHADS2, CHA2DS2-VASc, and HATCH scoring systems to predict AF progression and prognosis and identify the most useful scoring system in Korea. METHODS: A total of 559 consecutive patients with paroxysmal symptomatic AF were analyzed. The progression of AF and clinical outcomes were determined after at least 1 year of follow-up. Clinical outcomes were defined as the composite of death, hospitalization due to heart failure, and new-onset stroke. Each score was calculated, and its predictive accuracy for AF progression and prognosis was compared. RESULTS: A total of 147 patients with paroxysmal AF (26.3%) proceeded to persistent AF. The HATCH score (area under the curve [AUC], 0.601; p or = 6: 55.6%, linear p < 0.001) than the CHADS2 (AUC, 0.720) and HATCH scoring systems (AUC, 0.723). CONCLUSIONS: Although the CHADS2, CHA2DS2-VASc, and HATCH scoring systems were useful predictors of progression from paroxysmal to persistent AF, the CHA2DS2-VASc score was the most useful and accurate for the prediction of clinical outcomes.

Left Atrial Volume is a Predictor of Major Adverse Cardiac Events in Patients with Acute Myocardial Infarction / 대한내과학회지

BACKGROUND/AIMS: Diastolic dysfunction may develop in conjunction with or without systolic dysfunction in patients with acute myocardial infarction (AMI). The present study investigated the association between left arterial (LA) volume and major adverse cardiac events (MACE) in 772 patients with AMI. METHODS: The patients were divided into groups according to LA volume index (LAVI) measured using echocardiography according to the American Society of Echocardiography guidelines: LAVI > or = 40 mL/m2 (Group I: n = 260, 191 males; age, 71.1 +/- 10.8 years) and LAVI < 40 mL/m2 (Group II: n = 512, 432 males; age, 62.8 +/- 12.7 years). The mean observational period was 314.2 +/- 134.6 days. RESULTS: Group I patients were older than those in Group II. Hypertension (56.8% vs. 46.0%, respectively; p = 0.007) and advanced Killip class (42.6% vs. 21.0%, respectively; p < 0.001) were more frequent in Group I than in Group II. MACE was more prevalent in Group I than in Group II (20.3% vs. 13.7%, respectively; p = 0.037). MACE-free survival rates were higher in Group II than in Group I during clinical follow-up. The multivariate analysis revealed that high LAVI was an independent predictor of mortality (hazard ratio, 3.002; confidedce interval, 1.051-8.569; p = 0.040). CONCLUSIONS: LA volume is an independent predictor of adverse cardiac events in patients with AMI, and the LAVI is useful for AMI risk stratification.

Characteristics, In-Hospital and Long-Term Clinical Outcomes of Nonagenarian Compared with Octogenarian Acute Myocardial Infarction Patients

We compared clinical characteristics, management, and clinical outcomes of nonagenarian acute myocardial infarction (AMI) patients (n=270, 92.3+/-2.3 yr old) with octogenarian AMI patients (n=2,145, 83.5+/-2.7 yr old) enrolled in Korean AMI Registry (KAMIR). Nonagenarians were less likely to have hypertension, diabetes and less likely to be prescribed with beta-blockers, statins, and glycoprotein IIb/IIIa inhibitors compared with octogenarians. Although percutaneous coronary intervention (PCI) was preferred in octogenarians than nonagenarians, the success rate of PCI between the two groups was comparable. In-hospital mortality, the composite of in-hospital adverse outcomes and one year mortality were higher in nonagenarians than in octogenarians. However, the composite of the one year major adverse cardiac events (MACEs) was comparable between the two groups without differences in MI or re-PCI rate. PCI improved 1-yr mortality (adjusted hazard ratio [HR], 0.50; 95% confidence interval [CI], 0.36-0.69, P<0.001) and MACEs (adjusted HR, 0.47; 95% CI, 0.37-0.61, P<0.001) without significant complications both in nonagenarians and octogenarians. In conclusion, nonagenarians had similar 1-yr MACEs rates despite of higher in-hospital and 1-yr mortality compared with octogenarian AMI patients. PCI in nonagenarian AMI patients was associated to better 1-yr clinical outcomes.

Surface roughness analysis of ceramic bracket slots using atomic force microscope / 대한치과교정학회지

OBJECTIVE: This study was designed to measure the surface roughness at the slot floor of various ceramic brackets. METHODS: One kind of stainless steel bracket (Succes(R)), two kinds of monocrystalline brackets (Inspire Ice(R), Perfect(R)) and two kinds of polycrystalline brackets (Crystalline V(R), Invu(R)) were examined. Atomic force microscopy (AFM) was used to measure the surface roughness of each bracket. Data acquisition and processing were performed using SPIP(TM). RESULTS: The differences in values of Sa, Sq, and Sz in Invu(R) and Inspire Ice(R) were not statistically different from the control group Succes(R). The values of Sa, Sq, and Sz of Perfect(R) and Crystalline V(R) were greater than those of Succes(R). Differences of all the Sa, Sq, and Sz values between Perfect(R) and Crystalline V(R) were not statistically significant. CONCLUSIONS: It is concluded that the slot surfaces of Succes(R), Inspire Ice(R), and Invu(R) were smooth compared to those of Crystalline V(R) and Perfect(R).

Predictors of total occlusion of the infarct-related artery in patients with acute Non-ST elevation myocardial infarction / 대한내과학회지

BACKGROUND/AIMS: Some patients with non-ST elevation myocardial infarction (NSTEMI) have total occlusion of the infarct related artery (IRA) and may benefit from early invasive treatments. The aim of this study was to investigate the predictors of total occlusion of the IRA in patients with NSTEMI before coronary angiography. METHODS: A total of 205 consecutive patients with NSTEMI (63.3+/-10.5 years, 123 males) who were admitted and underwent coronary angiogram from April 2005 to December 2006 at Chonnam National University Hospital were divided into two groups: group I (total occlusion of IRA: n=62, 61.1+/-13.3 years, 42 males) and group II (patent IRA: n=143, 64.2+/-11.3 years, 81 males). Clinical, biochemical and echocardiographic parameters on admission were compared between the groups. RESULTS: A total occlusion of the IRA in patients with NSTEMI was observed in 62 (30.2%) patients most frequently in the left circumflex coronary artery. The predictive factors for total occlusion, according to the multivariate analysis, were prolonged duration of continuous chest pain (OR:9.67, 95% CI:1.59~80.6, p=0.03), a higher level of the creatine kinase-MB fraction (CK-MB) (OR:5.35, 95% CI:1.31~90.0, p=0.035) and fibrinogen (OR:6.73, 95% CI:1.48~50.2, p=0.043), and multiple leads with ST depression on the ECG (OR:4.78, 95% CI:1.22~41.9, p=0.048). CONCLUSIONS: Total occlusion of the IRA in patients with acute NSEMI is associated with a long duration of chest pain, high levels of CK-MB and fibrinogen, and ST changes in multiple ECG leads.

Contact non-linear finite element model analysis of initial stability of mini implant / 대한치주과학회지

Mini implants had been used provisionally for the healing period of implants in the beginning. But it becomes used for the on-going purpose, because it is simple to use, economic and especially suitable for the overdenture. But there is few studies about the stability of mini implants, that is most important factor for the on-going purpose, and particularly the implant parameters affecting the initial stability. The purpose of this study was to evaluate the stress and the strain distribution pattern of immediate- loaded screw type orthodontic mini-implant and the parameters affecting the initial stability of immediate-loaded mini-implant. Two dimensional finite element models were made and contact non-linear finite element analysis was performed. The magnitude and distribution of Von Mises stresses were evaluated. The obtained results were as follows: 1. The stress was concentrated on the thread tip of an implant in the cortical bone. 2. The direction of load is the most important factor for the stress distribution in cortical bone. 3. The diameter of an implant is the most important factor for the stress distribution in the trabecular bone. In conclusion, if the horizontal load vector is successfully controlled, mini-implants, which diameter is under 3mm, can be used for the on-going purpose.

Elementary School Students' Knowledge, Behavior and Request for Education Method Associated with Food Safety

We investigated elementary school students' knowledge, behavior, experience and preference of education method related to food safety in order to provide basic information for food safety educational program. A survey study was conducted with 569, fourth and sixth grade students, from two schools in Seoul and Ulsan. Students were asked thirty-two questions regarding food safety knowledge, behavior and experiences as well as their attitude to food safety class and preference for teaching method. The data was analyzed for the frequency analysis, t-test, chi-square test, one-way ANOVA and Pearson correlation using the SPSS/Windows. Results indicated that 91.9 percent of the respondents did not know what unsanitary food is. 67 percent of the respondents did not know the proper method of hand washing. Although the students' level of knowledge and behavior associated with food safety was low, there was meaningful correlation(r =.184, p<.01) between knowledge and behavior. Surprisingly, students in higher grade did not demonstrate an exceeding food safety knowledge and behavior. More than 50 percent of the subjects did not have food safety education either at home or school. 60 percent of the respondents interested in food safety and the majority recognized that a food safety education is needed. Students want to learn about unsanitary food(34.1%), foodborne illness(29.7%), food selection and storage method(21.3%), and personal hygiene(11.2%) through game, role play, and practice in real situation. These results suggest that development of food safety education program is needed through the elementary school year and the education program must include fun activities in which students can participate.

Three-dimensional finite element analysis on the effect of maxillary incisor torque / 대한치과교정학회지

The purpose of this study was to investigate the stress distribution in the periodontal tissue and the displacement of teeth when active torque was applied to the maxillary incisors by three-dimensional finite element analysis. A three-dimensional finite element model consisted of the maxillary teeth and surrounding periodontal membrane, .022 x .028 Roth prescription bracket and stainless steel, NiTi and TMA rectangular ideal arch wires which were modeled by hexahedron elements. Applied active torques were 2, 5 and 10 degrees. The findings of this study showed that the reaction force acting on the bracket was the extrusion force on the mesial side of the incisors and canine and the intrusion force on the distal side of the incisors and canine. The amount of force and moment was greatest at the lateral incisor. When active anterior labial crown torque was applied, labial crown and distal tipping and intrusion of the incisors took place, and lingual crown distal tipping and extrusion of the canine occured. An excessive force was concentrated on the lateral incisor, when the stainless steel wire was used. NiTi or TMA wire is desirable for torque control.