This study was performed to evaluate the effect of aging and thermal cycling on the biaxial flexure strength of four commercially available veneering resin composites for crown(Dentacolor : DC, Artglass : AG, Esternia : ET and Targis : TG). Disc specimens were fabricated in a teflon mold giving 12mm in diameter and 1mm in thickness. All samples were divided into 4groups. Group 1 was dried in a dessicator at 25degrees C for 30 days. Group 2 was immersed in distilled water at 37degrees C for 30 days. Group 3 was immersed in distilled water at 65degrees C for 30 days. Group 4 was subjected to 10,000 thermal cycles between 5degrees C and 55degrees C, and the immersion time in each bath was 15 seconds per cycle. Biaxial flexure test was conducted using the ball-on-three-ball method at the cross head speed of 0.5mm/min and fracture surfaces were observed with scanning electoron microscope. The results obtained were summarized as follows ; 1. Weibull modulus values, except for the AG group, decreased after thermal cycling treatment. 2. Biaxial flexure strength values of aging group at 37degrees C were th lowest in all sample groups. Except for the DC group, strength values were significntly decreased for the drying group. 3. After thermal cycling test, the highest value of biaxial flexure strength of 188.8 MPa was observed in the ET group and the lowest value of 73.2 MPa was observed in the DC group. The strength values showed the significant differences in each group (p<0.05). 4. Observation of surfaces after thermal cycling test revealed the ditching in the part f surrounding large fillers.
Aging* ; Baths ; Crowns* ; Fungi ; Head ; Immersion ; Polytetrafluoroethylene ; Water

BACKGROUND AND OBJECTIVES: Intracardiac electrocardiographic finding using as a guide for selective catheter ablation in patients with AV nodal reentrant tachycardia (AVNRT) is not specific. Therefore, we evaluated the efficacy and safety of the anatomical approach for catheter ablation in patients with AVNRT. MATERIALS AND METHOD: Among the patients diagnosed as AVNRT by electrophysiologic study, total 66 patients (M:F=26:40) were included in this study. In the right anterior oblique radiographic view, the septal annulus of tricuspid valve, extending from the most posterior region of the annulus adjacent to coronary sinus ostium (posterior) to His bundle recording site (anterior), was divided into posterior (P), mid (M), and anterior (A) sites. Radiofrequency (RF) energies were applied from the posterior part to the anterior part sequentially along the septal annulus of tricuspid valve until successful ablation. RESULTS: Successful anatomical sites were located in posterior (11 patients), mid (48 patients), and anterior (7 patients) sites. The most patients (62 patients) were treated with slow pathway ablation except 4 patients in whom fast pathway was ablated. Probable slow potentials were observed in 8 patients (12%, 3 in posterior sites and 5 in mid sites). Transient complete AV block followed by first degree AV block and delayed complete AV block was occured in one case whose ablation site was A1. And another 3 patients had postablation first degree AV block. CONCLUSION: In patients with AVNRT, the ablated pathway were different according to successful anatomical site. And RF catheter ablation of atrioventricular nodal reentrant circuit guided by anatomical landmark is safe and efficacious.
Atrioventricular Block ; Bundle of His ; Catheter Ablation* ; Catheters* ; Coronary Sinus ; Electrocardiography ; Humans ; Tachycardia, Atrioventricular Nodal Reentry* ; Tricuspid Valve

A 17-year-old woman had an extensive nevus comedonicus affecting the left sides of the breast, trunk, axilla, and upper extremity. Her condition was complicated by episodes of re-current cyst formation, secondary infection, and atrophic scars. We performed various therapeutic approaches include topical keratolytic agents, manual extraction of comedones, excision of smaller lesions, and systemic antibiotics but the response was unsatisfactory. We tried systemic isotretinoin and minocycline and the pustulation of the lesions was reduced. Herein we report a rare case of linearly arranged extensive nevus comedonicus.
Adolescent ; Anti-Bacterial Agents ; Axilla ; Breast ; Cicatrix ; Coinfection ; Female ; Humans ; Isotretinoin ; Keratolytic Agents ; Minocycline ; Nevus* ; Upper Extremity

No abstract available.
Brain Stem* ; Evoked Potentials* ; Hallucinations* ; Humans

BACKGROUND: Induction of general anesthesia with tracheal intubation and skin incision are potent stimuli that can induce increased sympathetic activity, heart rate and blood pressure. We compared the hemodynamic response and catecholamine concentration during general anesthesia with intravenous clonidine pretreatment, a centrally acting -2 adrenoceptor agonist, and without pretreatment. METHODS: Forty ASA I or II patients aged from 20 to 60 years undergoing elective surgery were randomly allocated to two groups. In group I, 5 ml of 0.9% normal saline as control administered intravenously 10 minutes before induction of anesthesia, and anesthesia was induced with thiopental sodium, succinylcholine and maintained with N2O (2.5L/min)-O2 (2.5L/min)-enflurane (1.3~1.8 vol%). In group II, 4 g/kg clonidine diluted in 5ml of normal saline administered intravenously 10 minutes before induction of anesthesia, and anesthesia was induced with thiopental sodium, succinylcholine and maintained with N2O-O2-enflurane (0.5~1.0vol%) and 2 g/kg/hr clonidine was continuously infused. We measured blood pressure, heart rate and plasma catecholamine at preinduction, 1 minute after intubation (T1), 1 (T2) and 30 minutes after skin incision (T3) and compared with group I. RESULTS: There was statistical significance in systolic and diastolic pressure at T1 between two groups. There was statistical significance in heart rate, epinephrine and norepinephrine at T1, T2 and T3 between two groups. CONCLUSION: The elevation of blood pressure, heart rate and plasma catecholamine accompanying tracheal intubation and skin incision may be prevented by administration of intravenous clonidine.
Adult ; Anesthesia ; Anesthesia, General* ; Blood Pressure* ; Brain ; Clonidine* ; Epinephrine ; Heart Rate* ; Heart* ; Hemodynamics ; Hemorrhage ; Hope ; Humans ; Incidence ; Intubation* ; Larynx ; Male ; Norepinephrine ; Plasma* ; Skin ; Spondylitis, Ankylosing ; Succinylcholine ; Thiopental

No abstract available.

No abstract available.
Encephalitis, Arbovirus*

No abstract available.
Epilepsies, Partial* ; Paragonimiasis*

No abstract available.
Hyperplasia* ; Leishmania donovani* ; Leishmania*

No abstract available.
Hyperplasia* ; Leishmania donovani* ; Leishmania*