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

Kommerell diverticulum is a rare congenital anomaly of the aortic arch characterized by dilation at the proximal descending aorta, which gives rise to an aberrant subclavian artery. Kommerell diverticulum is usually asymptomatic, but can also be associated with symptoms due to compression of the esophagus or trachea, and can rarely be fatal due to dissection or rupture of the diverticulum. Here, we report a rare case of dysphagia caused by compression of the esophagus by Kommerell diverticulum originating from the right-sided aortic arch.

Pacemaker implantation for patients with mechanical tricuspid valve is quite challengeable because lead insertion through prosthetic tricuspid valve may cause valve dysfunction or lead impingement. Also complications due to interrupt of anticoagulation should be considered. A 65 years old woman received AAI (atrium paced, atrium sensed, inhibited) pacemaker for sick sinus syndrome and mechanical mitral valve replacement for severe mitral steno-insufficiency at the same time 16 years before. She needed to undergo mechanical tricuspid valve replacement (TVR) because of severe tricuspid regurgitation despite of medical therapy. Complete atrioventricular block developed during the TVR operation and it was not recovered even after several days of temporary pacing. We decided left ventricular pacing through coronary sinus because ventricular lead could not pass mechanical tricuspid or mitral valve and also planned to continue oral anticoagulation therapy. We could find a place where high pacing output did not pace phrenic nerve with acceptable sensing, pacing threshold. The patient recovered well without any periprocedural complications. Left ventriclcular pacing lead implantation through coronary sinus without interruption of anticoagulation can be an alternative to epicardial pacing for patients with mechanical tricuspid valve.
Atrioventricular Block ; Coronary Sinus ; Female ; Humans ; Mitral Valve ; Phrenic Nerve ; Sick Sinus Syndrome ; Tricuspid Valve Insufficiency ; Tricuspid Valve*

BACKGROUND/AIMS: Coronary vasospasms are one of the important causes of sudden cardiac death (SCD). Provocation of coronary vasospasms can be useful, though some results may lead to false positives, with patients potentially experiencing recurrent SCD despite appropriate medical treatments. We hypothesized that it is not coronary vasospasms but inherited primary arrhythmia syndromes (IPAS) that underlie the development of SCD. METHODS: We analyzed 74 consecutive patients (3.8%) who survived out-of-hospital cardiac arrest among 1,986 patients who had angiographically proven coronary vasospasms. Electrical abnormalities were evaluated in serial follow-up electrocardiograms (ECGs) during and after the index event for a 3.9 years median follow-up. Major clinical events were defined as the composite of death and recurrent SCD events. RESULTS: Forty five patients (60.8%) displayed electrocardiographic abnormalities suggesting IPAS: Brugada type patterns in six (8.2%), arrhythmogenic right ventricular dysplasia patterns in three (4.1%), long QT syndrome pattern in one (2.2%), and early repolarization in 38 (51.4%). Patients having major clinical events showed more frequent Brugada type patterns, early repolarization, and more diffuse multivessel coronary vasospasms. Brugada type pattern ECGs (adjusted hazard ratio [HR], 4.22; 95% confidence interval [CI], 1.16 to 15.99; p = 0.034), and early repolarization (HR, 2.97; 95% CI, 1.09 to 8.10; p = 0.034) were ultimately associated with an increased risk of mortality. CONCLUSIONS: Even though a number of aborted SCD survivors have coronary vasospasms, some also have IPAS, which has the potential to cause SCD. Therefore, meticulous evaluations and follow-ups for IPAS are required in those patients.
Arrhythmias, Cardiac* ; Arrhythmogenic Right Ventricular Dysplasia ; Coronary Vasospasm* ; Death, Sudden, Cardiac* ; Electrocardiography ; Follow-Up Studies ; Heart Arrest ; Humans ; Long QT Syndrome ; Masks* ; Mortality ; Out-of-Hospital Cardiac Arrest ; Survivors