Neurotransmitter modulator (TENS) for control of dental operative pain.

A pain control study of 600 dental procedures was undertaken during a 1-year period. The procedures varied from vigorous subgingival scaling to endodontic procedures. Most procedures involved the placement of two- and three-surface anterior and posterior restorations. Results were evaluated for pain control related to procedure type, patients' level of relaxation, sensitivity to pain, and patients' skepticism about the success of the reduction in pain during the procedure. Electrical analgesia with neurotransmitter modulator (TENS) was a valuable adjunctive tool for scaling, prophylaxis, and restorative procedures.

Neuromotor disorders of the esophagus.

Esophageal motility studies are helpful in diagnosing hypertensive and hypotensive disorders of the esophagus and its sphincters, including the exact measurement of the strength of contraction, temporal sequence and duration of the pathophysiology involved. In addition, the assessment of the extent of neuromotor involvement may be of great help to the surgeon in planning a myotomy. PH metering is probably the most accurate way to assess reflux in hypotonic states.

In vitro corrosion of dental amalgam phases.

The effects of corrosion on the major phases of dental amalgam microstructure have been studied in vitro on samples prepared by electroplating mercury on Ag3Sn. Tests were made in synthetic saliva, and samples were examined in a scanning electron microscope before and after the exposure. Simple immersion had little effect on the phases. Contact of amalgam with gold increased the probability of deterioation of the gamma2 phase. By anodic polarization beyond the breakdown potential, the gamma2 phase was selectively dissolved. Under conditions simulating a crevice, the gamma2 phase was dissolved and the gamma1 phase suffered morphological changes.

Amalgamation reaction on mercury-plated dental alloy (Ag3Sn).

The reaction between liquid mercury and Ag3Sn was studied at room temperature using a new type of specimen; i.e. bulk Ag3Sn electroplated with mercury. The surface morphology of the specimen and the phases formed on the Ag3Sn substrate were investigated by various techniques including optical microscopy, electron (scanning) microscopy, electron microprobe analysis, and electron diffraction. It was found that the mode of formation and type of crystalline phase appearing on the Ag3Sn specimen depended on the amount of mercury available. When the amount of mercury exceeded a certain quantity (about 1 mg/cm2) only the gamma1 and gamma2 phases were formed. On the other hand, when the amount of mercury was reduced below a certain low value (less than 0.3 mg/cm2), another silver-mercury phase, beta1, formed as tiny "liquid-like" drops. The experimental technique employed in the present investigation has proved to be an excellent method for studying the reaction between liquid mercury and metal specimens. This new procedure may be employed to evaluate the amalgamation ability of potential new alloy systems.

Cricopharyngeal obstruction in inflammatory myopathy (polymyositis/dermatomyositis). Report of three cases and review of the literature.

Three adults, 2 of whom had polymyositis and 1 with dermatomyositis, developed dysphagia during the course of their illness. Results of esophageal manometry supplemented with esophageal radiography indicated the presence of cricopharyngeal achalasia. Because of the severity of this disorder, which is associated with aspiration of esophageal contents into the airways, surgery to divide the cricopharyngeal musculature was performed in 2 patients, giving complete relief of their symptoms. Prednisone dosage was not increased to treat this condition since it arose not from weakness but from obstruction. A biopsy specimen taken from 1 patient demonstrated inflammatory changes in the obstructing muscle. A review of these 3 patients and 3 previously reported cases indicates that cricopharyngeal obstruction can be a dominant cause of dysphagia in patients with myositis. The recognition of this entity is important in the management of patients with myositis because: it has serious and potentially life-threatening implications; and in certain cases, it can be effectively treated with surgery.

Growth kinetics of gamma 2 crystals on mercury-plated Ag3Sn.

Previous work has shown that needles of gamma 2 crystals form when mercury is plated on the surface of an Ag3Sn specimen. In the present study, the growth kinetics of gamma 2 needles were investigated from room temperature to 50 degrees C for varying amounts of plated mercury. Straight-line relationships between crystal length and the square root of the time of growth showed that the growth rate is diffusion controlled. The growth rate increased with temperature up to 40 degrees C but decreased at higher temperatures. Further, as the temperature was increased, fewer gamma 2 crystals formed and their growth length decreased. This demonstrates that a number of competing factors are involved in the growth process at high temperatures.

An investigation of the bacteriostatic properties of pure metals.

The effect of 16 pure metals on the in vitro growth of a form of dental caries producing Streptococcus mutans was studied under both aerobic and anaerobic conditions. Cobalt and copper were consistently observed to be inhibitory. With less consistency nickel, titanium, iron, and vanadium also exhibited ability to inhibit growth of the organism. Bacteriostasis apparently is contingent upon the presence of a corrosion process. The bacteriostatic agent is of uncertain identity and could be a corrosion product or a process secondary to the occurrence of corrosion. Concentrations of metals after 6 days of electrochemical dissolution in the growth medium were measured via electron microprobe analysis and compared with the amount of inhibition which resulted. Threshold concentrations above which growth did not occur were identified. As measured by threshold concentrations, wide variability between metals exists in the ability to inhibit the growth, with cobalt being particularly effective at small concentrations. This implies a sensitivity on the part of the organism that is different for different metals. The threshold concentration varied between aerobic and anaerobic conditions. Streptococcus mutans appeared more resistant to the effects of the metals under anaerobic conditions even though little difference in the amount of corrosion was detected.

In vivo and in vitro studies of the stress-corrosion cracking behavior of surgical implant alloys.

Behavior of implant alloys exposed simultaneously to tensile stresses and corrosion environments has been examined. In the in vivo studies, a stainless steel and a titanium alloy exhibited cracklike features when loaded to the yield stress sigma y and implanted for 16 weeks. A cobalt-chromium alloy stressed beyond sigma y exhibited them in plastically deformed areas. A cobalt-chromium-nickel-molybdenum alloy appeared to be immune. In vitro samples loaded to various stress levels were immersed in Ringer's solution at 37 degrees C. Half of them were subjected to applied anodic potentials; the remaining control group was not. The applied potentials were dc potentials of magnitude similar to those generated by bioelectric effects. No attempt was made to duplicate time dependence or wave forms. Cracklike features were observed in the stainless steel and in the titanium alloy loaded to or beyond sigma y and polarized for 38 weeks. None were observed below sigma y. For the controls, no cracklike features were observed at any stress level after 53 1/2 weeks. Polarization measurements and potential versus time measurements were performed to study possible mechanisms for crack propagation. These investigations suggest that the in vivo corrosion environment is more severe than a 37 degrees C Ringer's solution because of the influence of both bioelectric effects and organic constituents. The implications of these studies for the performance of prosthetic devices is discussed.

Cogan's syndrome: acute vestibular and auditory dysfunction with interstitial keratitis.

Two patients with Cogan's syndrome had acute bilateral hearing loss and vestibular dysfunction. Interstitial keratitis was discovered by slit-lamp examination. Both cases responded to corticosteroid treatment. Immediate recognition of this syndrome and the institution of high-dose corticosteroid therapy should lead to resolution of the hearing loss in patients with Cogan's syndrome.

Auger analysis of surface films on Ag3Sn.

The surface properties of Ag3Sn are important in the amalgamation process so that mechanical abrasion is generally necessary to get a satisfactory amalgam. Therefore, the present study was undertaken to characterize the surface of Ag3Sn after several types of surfaces treatments. Homogeneous polycrystalline rods of Ag3Sn were prepared in vacuo from high purity (99.99%) Ag and Sn. Specimens were sliced from these rods and prepared as follows: (1) mechanically polished, (2) polished as in (1) and allowed to sit in air for three days and (3) polished as in (1) and electrolytically etched. Each of these specimens was examined by Auger electron spectroscopy. The results showed that after mechanical abrasion the surface film was primarily oxide and the Ag to Sn ratio was lower than the bulk composition, indicating preferential oxidation of Sn. After sitting in air sulfur was also present on the surface and the Ag to Sn ratio was greater than that immediately after polishing, indicating the formation of Ag2S. After electrolytic etching some oxide was still present, but only a trace of sulfide was found. However, the Ag to Sn ratio was greater than that for mechanically polished specimens, indicating preferential dissolution of Sn. Therefore, it is seen that the surface preparation of Ag3Sn has a marked effect on Ag and Sn concentrations and the nature of films at the surface.

High-dose intravenous gamma-globulins for heparin-induced thrombocytopenia: a prompt response.

Heparin-induced thrombocytopenia (HIT) is a common drug induced autoimmune condition. The thrombocytopenia is caused in most cases by an antibody directed against the complex PF4/heparin. Recently, we have induced an experimental model of HIT by idiotypic manipulation. To confirm further the idiotypic involvement of HIT, we have treated successfully three patients with HIT with high-dose intravenous gamma-globulin (IVIG). Our three patients joint other two cases previously reported who were treated with IVIG and point to the efficacy of this type of therapy with minimal side effects. IVIG suppression of the anti-PF4/heparin autoantibody may support the idiotypic etiology of HIT.

Coagulopathy associated with the use of cephalosporin or moxalactam antibiotics in acute and chronic renal failure.

Nine azotemic patients who developed a coagulopathy associated with the use of either cephalosporin or moxalactam antibiotics are reported. The acute renal failure patients had neoplastic disorders and were considered to be septic at the time that multiple antibiotics were administered. Four of 5 chronic hemo- or peritoneal dialysis patients also received multiple antibiotics. Nevertheless, the coagulopathy seemed to be most closely associated with the administration of the cephalosporin. One patient received moxalactam as part of the combination therapy for diffuse pulmonary infiltration during renal transplant rejection. Bleeding occurred into the gastrointestinal tract in four patients, into the kidney-urinary tract in three patients, into vascular surgical sites in two patients, and one each into the pulmonary-bronchial and cerebral-ventricular systems. Five operations were performed in four patients: a nephrectomy for massive subcapsular hemorrhage with a prothrombin time that exceeded 100 seconds; arteriovenous graft complicated by post-operative bleeding associated with prolongation of the prothrombin time; elective femoral-popliteal bypass complicated by a prolonged prothrombin time, bleeding into the graft site, hypotension, and a subendocardial myocardial infarction; elective cholecystectomy complicated by a two unit bleed associated with a slightly prolonged prothrombin time, followed by elective femoral-popliteal bypass complicated by a fatal intercerebral bleed associated with a more than twice normal prothrombin time. Cephalosporins are most likely associated with Vitamin K deficiency. Moxalactam is more likely to be associated with platelet dysfunction. Monitoring of the prothrombin time for cephalosporins or the bleeding time for moxalactam is the most reliable way to prevent what may be rapid emergence of clinical bleeding in patients with renal failure.

Concordance between clinician and patient assessment of physical and mental health status.

The degree of concordance between clinicians' and patients' assessment of the patient's physical and mental functioning was examined in 166 consecutive eligible outpatients with rheumatoid arthritis (RA) using 4-category ordinal scales. The weighted kappa statistic was 0.39 for physical functioning and 0.30 for mental functioning, both indicating a fair degree of concordance. This disagreement differed in magnitude and direction depending on the level of disability present. We conclude that clinicians and their patients with RA often disagree in their assessment of the degree of physical and mental impairment that the patient experiences. These disagreements demonstrate the need for formal assessments of outcome and should be recognized and resolved when managing individual patients.