Biomedical subjects
Publications and source records attributed to R Mitrani.
Three different procedures that involve the use of Triad gel are described. This light-polymerized resin material is versatile and easy to use in the dental clinic and laboratory. The procedures described include the transfer of ridge topography for ovate pontic sites, implant lab analog fixation, and solid/soft tissue cast fabrication.
Three different procedures that involve the use of Triad gel are described. This light-polymerized resin material is versatile and easy to use in the dental clinic and laboratory. The procedures described include the transfer of ridge topography for ovate pontic sites, implant lab analog fixation, and solid/soft tissue cast fabrication.
Implant prosthodontics is a predictable treatment modality for patients who require occlusal reconstruction. Specific indications include lack of distal abutment, long span segment, compromised natural abutments, and occlusal dysfunction. With proper treatment planning and an understanding of the occlusion and biomechanics of implant prosthodontics, the restorative team can predictably fabricate a functional, esthetic, and comfortable prosthesis.
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Multidisciplinary treatment was essential for this patient to optimally manage the occlusion and missing teeth. When the space distribution was completed, ridge management procedures for pontic site development were accomplished. The final restorative treatment required was actually minimized to a 7-unit fixed partial denture. It was apparent the multidisciplinary treatment was essential to predictably manage this patient by decreasing risk and ensuring a long-term strategy for enhanced patient satisfaction.
Arrhythmias in women may be affected by phases of the menstrual cycle. This study was designed to determine the prevalence of perimenstrual clustering of spontaneous episodes of paroxysmal supraventricular tachycardia (SVT) in women. It also tested the hypothesis that women with this temporal pattern of events have an altered probability of induction of paroxysmal SVT during electrophysiologic testing at higher estrogen states (midcycle or with estrogen replacement therapy) than at low estrogen states (perimenstrual or without estrogen replacement). A structured history of the relation of spontaneous paroxysmal SVTs to phases of the menstrual cycle was obtained prospectively among 42 women referred during a 3-year period. Patients with cyclical patterns of spontaneous tachycardias, who had had negative electrophysiologic studies at midcycle or while receiving estrogen replacement therapy, had repeat procedures (1) when premenstrual or at the onset of menses, or (2) after stopping estrogen replacement therapy. Seventeen of 42 consecutive female patients (40%) had histories of perimenstrual clustering of arrhythmias. Six women (4 with normal menstrual cycles, 2 on estrogen replacement therapy), who qualified for paired electrophysiologic studies because of a negative initial electrophysiologic study that included provocation with isoproterenol, had inducibility into SVTs during the second study. All 6 had dual atrioventricular (AV) nodal pathway physiology, 4 had AV nodal reentrant tachycardia (AVNRT) induced, 1 had both AVNRT and reciprocating AV tachycardias, and 1 had nonsustained AVNRT and an atrial tachycardia induced. Successful ablation procedures were performed in 5 of the 6 patients. Thus, among women with a history of perimenstrual clustering of paroxysmal SVT and among those receiving estrogen replacement therapy, scheduling of elective electrophysiologic procedures at times of low estrogen levels (premenstrual or off estrogen replacement therapy) may facilitate the probability of a successful procedure.
The objectives of this review are to discuss the diversity of mechanisms that may explain the association between heart rate (HR) variability and mortality, to appraise the clinical applicability of traditional and new measures of HR variability and to propose future directions in this field of research. There is a large body of data demonstrating that abnormal HR variability measured over a 24-h period provides information on the risk of subsequent death in subjects with and without structural heart disease. However, the mechanisms responsible for this association are not completely established. Therefore, no specific therapy is currently available to improve the prognosis for patients with abnormal HR variability. Reduced HR variability has been most commonly associated with a risk of arrhythmic death, but recent data suggest that abnormal variability also predicts vascular causes of death, progression of coronary atherosclerosis and death due to heart failure. A consensus is also lacking on the best HR variability measure for clinical purposes. Time and frequency domain measures of HR variability have been most commonly used, but recent studies show that new analysis methods based on nonlinear dynamics may be more powerful in terms of risk stratification. Before the measurement of HR variability can be applied to clinical practice and used to direct therapy, more precise insight into the pathophysiological link between HR variability and mortality are needed. Further studies should also address the issue of which of the HR variability indexes, including the new nonlinear measures, is best for clinical purposes in various patient populations.
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The influence of an X-ray dose of 10 Gy (1000 rads) on mitosis in the rat conjunctival epithelium was assessed. A mitotic inhibition began 1 hour postirradiation and continued for 4 days. The mitotic index was depressed to 10% of control values. After 5 days postirradiation, the mitotic index surpassed the control values peaking at 7 days postirradiation. The spindle axes of cells in telophase of the perilimbal rat conjunctival epithelium assume a characteristic, three dimensional orientation relative to the limbus. Ionizing radiation did not disrupt this organization at any time postirradiation. In fact, the frequency of mitotic figures preferentially aligned in irradiated tissue was enhanced during the mitotic rebound.
Tightening of the screws in implant-supported restorations has been reported to be problematic, in that if the applied torque is too low, screw loosening occurs. If the torque is too high, then screw fracture can take place. Thus, accuracy of the torque driver is of the utmost importance. This study evaluated 4 new electronic torque drivers (controls) and 10 test electronic torque drivers, which had been in clinical service for a minimum of 5 years. Torque values of the test drivers were measured and were compared with the control values using a 1-way analysis of variance. Torque delivery accuracy was measured using a technique that simulated the clinical situation. In vivo, the torque driver turns the screw until the selected tightening torque is reached. In this laboratory experiment, an implant, along with an attached abutment and abutment gold screw, was held firmly in a Tohnichi torque gauge. Calibration accuracy for the Tohnichi is +/- 3% of the scale value. During torque measurement, the gold screw turned a minimum of 180 degrees before contact was made between the screw and abutment. Three torque values (10, 20, and 32 N-cm) were evaluated, at both high- and low-speed settings. The recorded torque measurements indicated that the 10 test electronic torque drivers maintained a torque delivery accuracy equivalent to the 4 new (unused) units. Judging from the torque output values obtained from the 10 test units, the clinical use of the electronic torque driver suggests that accuracy did not change significantly over the 5-year period of clinical service.