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Background: To report a long-term single-site experience of the cut-and-sew Cox maze III procedure for atrial fibrillation (AF)., Methods: A total of 232 consecutive patients underwent the Cox maze III procedure for symptomatic therapy-refractory AF, with concomitant surgery in 34 patients. Follow-up data were obtained from electrocardiograms, patient visits, questionnaires, and medical files., Results: There were 103 patients (44%) with paroxysmal AF during 8.8 ± 6.5 years and 129 patients (56%) with nonparoxysmal AF for 7.3 ± 6.7 years. The preoperative New York Heart Association class was better in patients with paroxysmal AF (P < 0.0001); the left ventricular ejection fraction was 59 ± 7% versus 56 ± 8%, P = 0.003, and the left atrial area 24 ± 6 versus 27 ± 6 cm(2) , P = 0.01. Early and late postoperative adverse events occurred at similar rates. Four patients from each group died of reasons unrelated to surgery. The mean follow-up was 66 ± 42 (5-155) months. In total, 184/229 (80%) patients were free of documented AF/atrial flutter/atrial tachycardia (AF/AFl/AT) off antiarrhythmic drugs (AA) and 189/229 (83%) on or off AA. The hazard ratio (HR) for paroxysmal versus nonparoxysmal AF patients regarding documented AF/AFl/AT was 0.8 (95% confidence interval [CI] 0.4-1.4; P = 0.40). For patients without versus with concomitant surgery, the corresponding HR was 0.4 (95% CI 0.2-0.8; P = 0.008). Of 197 patients (89%) responding to the questionnaire, 41 had sought care for symptoms of arrhythmia, 29 of whom had documented AF/AFl/AT, whereas another six had other arrhythmias., Conclusion: Cut-and-sew Cox maze III surgery provided long-lasting high efficacy, also in patients with nonparoxysmal AF of long duration and/or concomitant surgery, and was associated with low rates of subsequent adverse events., (©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.)

A 61-year-old male was treated with cryoablation for typical atrial flutter. Cryoablation was performed percutaneously with an 8-mm tip catheter to achieve a bidirectional conduction block of the cavo-tricuspid isthmus. When freezing at the point where bidirectional isthmus block occurred, the patient experienced chest pain and ECG showed ST segment elevations corresponding to the right coronary artery. Cryoablation may be painless per se, but patients should be told to report chest discomfort and surface ECG must be followed carefully during ablation.

The potential exists for titanium and amalgams to become galvanically coupled in the oral cavity. While low galvanic corrosion rates have been measured in vivo for titanium-amalgam or mercury-free alloy couples, concerns exist over released corrosion products and adverse tissue responses. It was hypothesized in this study that coupling titanium to amalgams or gallium alloys increased the release of metallic corrosion products and decreased cellular activity and function. The effects of titanium coupled and uncoupled to a conventional amalgam, palladium-enriched spherical high copper amalgam, a dispersed type high copper amalgam, and a mercury-free gallium alloy were evaluated in 24-h cell culture tests. Viability, proliferation, and collagen synthesis were evaluated by the uptake of neutral red, 3H-thymidine, and immunoassay of procollagen, respectively, and compared to cells not exposed to any test material. The gallium alloy-titanium couple resulted in significant decreases in cellular viability, proliferation, and collagen synthesis as compared to the other coupled and uncoupled samples. Few differences in the cellular responses of the other coupled and uncoupled samples were observed. Atomic absorption analyses indicated increased release of metal ions from the amalgam and gallium alloy samples coupled to titanium as compared to their uncoupled condition, although the differences were not always significant. Galvanic corrosion of amalgam-titanium couples in the long term may become significant, and further research is needed. Coupling the gallium alloy to titanium may result in increased galvanic corrosion and cytotoxic responses.

The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high-copper, and a palladium-enriched spherical high-copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24-h direct contact human gingival fibroblast cell cultures. Results of this study indicated that before connecting the high-copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam-titanium couples as compared to the gallium alloy-titanium couple. Coupling the conventional or the palladium-enriched high-copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed-type high-copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.

Objectives: The aim of this investigation was to study the effect of surface treatments and electrode area size on the corrosion of cast and machined titanium in contact with conventional and high-copper amalgams in saline solutions with and without added fluoride ions., Methods: The potentials and the charges transferred between amalgam and titanium couples were registered using standard electrochemical methods., Results: Conventional amalgam corroded more than high-copper amalgams in contact with titanium in saline solutions. Adding fluoride to the solution made the titanium potential more active and enhanced the corrosion of titanium in combination with high-copper amalgams. The amalgam corrosion increased with a five-fold enlargement of the titanium area. The increase was significant for one titanium-amalgam combination. Surface preparations affected the electrochemical behavior, and surface alterations were occasionally observed on wet-ground titanium specimens. No significant differences were found in comparisons of cast and lathe-cut titanium., Significance: Surface preparations and fluoride affect the electrochemical activity of titanium.

The effect of different sodium chloride concentrations on the integrated currents (charge transfers) between dental amalgams and a gold alloy was studied in a bimetallic cell containing saliva or saline solutions. The integrated currents were only to a minor degree affected by increasing chloride concentrations for the high copper amalgams both in saliva and saline solutions. The integrated currents in the experiments involving conventional amalgam were several times higher than those for high copper amalgams. In saline solutions a charge transfer maximum was found at 0.2 M chloride. In saliva an increase of the charge transfer was found with increasing chloride content.

Materials used for the construction of dental restorations and implants include a wide range of metals and alloys, ceramics and carbons, and polymers. When metals and alloys are placed in direct contact in the oral cavity, a galvanic cell can be formed that may compromise the longevity of one or more of the materials in the couple. In vitro electrochemical corrosion analyses have proven to be a valuable tool for providing guidance on the selection of metallic materials. These analyses can provide basic data on electrochemical potentials, current rates, and the evaluation of galvanic corrosion conditions. This article seeks to provide the clinician with information that can be valuable in the selection of metallic materials that may be placed in direct contact with one another in the oral cavity.

Metallic materials in the oral cavity cannot be expected to be inert. However, the electrochemical interaction with the environment, may vary considerably. Corrosion of dental metallic materials has been said to cause local, and even general unpleasant effects. Different forms of corrosion and variations in the complex oral milleu make it difficult to estimate and predict the corrosion occurring. Various methods such as the recording of potentials, potential differences and currents have been used to study the corrosion which may occur when metallic restorations or appliances come into contact. However, an improvement should be obtained if data which are more closely related to the ion release due to short-circuiting could be recorded. Calculated currents were related to those directly measured and the knowledge thus obtained was used to design a convenient equipment for clinical registration of the charge transfer between short-circuited restorations or appliances. The equipment was used in a study of patients with disorders/discomfort allegedly caused by corrosion in the oral cavity. Furthermore, the released quantity of tin and the charge transfer between amalgam and gold alloy electrodes were studied both in vitro and clinically. The currents flowing between amalgam and gold alloy electrode couples were compared using different electrolytes. The findings may be summarized as follows: The quantity of tin released in vitro was related to the charge transferred between short-circuited electrodes consisting of a conventional amalgam and a gold alloy and the same tendency could be shown clinically. When electrodes made of a gold alloy and various types of amalgams were short-circuited, the currents recorded were influenced by the composition of the amalgams and of the electrolytes. The equipment constructed admitting measurements of the charge transfer seems to be suitable for an estimation of corrosion due to contacts between metallic restorations/appliances. No differences could be found when a referred group of patients with disorders/discomfort allegedly caused by corrosion of dental metallic materials was compared with a control group of people with roughly the same type and distribution of metallic restorations/appliances when each individual was represented by the highest charge transfer and the total added charge transfers, respectively. Some of the patients' disorders/discomfort can be related to the occurrence of affections and conditions, the treatment of which falls within the scope of the dentist.

Thirty referred patients and 15 control subjects were investigated with reference to the occurrence of bimetallic corrosion in the oral cavity. No differences between patients and controls could be found regarding the registered charge transfer between dissimilar short-circuited dental metallic restorations and/or appliances. However, a relatively large number of periodontal and mucous membrane affections, carious lesions and stomatognathic and/or temporomandibular joint disturbances were found within the patient group.

The marginal degradation and corrosion of restorations made of a high copper dispersed amalgam were studied as a function of time for up to 5-yr observation periods. The effect of minor defects present after finishing the restorations was included in the assessment of the initial marginal degradation. A slow progressive marginal degradation was noted and it was enhanced by initial defects. Subsurface corrosion including attacks of the phase and grain boundaries, corrosion within the bulk, and layers of corrosion products along the tooth/restoration interfaces were observed in restorations after some years in clinical service. The subsurface corrosion is considered to weaken the amalgam and it might enhance the marginal degradation, i.e. a stress corrosion type of degradation.

The corrosion behavior of commercially available copper, nickel, and gold alloys for dental castings was investigated. The alloys investigated included: three copper alloys (76-87Cu, 6-11A1, 0-12Zn, 1-5Ni, 0-4Fe, 0.5-1.2Mn), two nickel alloys (68-78Ni, 12-16Cr, 4-14Mo, 0-1.7Be), and one gold alloy (77Au, 14Ag, 8Cu, 1Pd). Anodic and cathodic polarization curves, long-term immersion tests in saline and artificial saliva solutions, and dog crown studies were conducted to evaluate both the in vitro and in vivo corrosion characteristics of the alloys. All evaluations conducted demonstrated that the copper alloys were highly susceptible to corrosion attack. High corrosion currents were observed in the in vitro tests, and SEM of the alloys specimens showed significantly altered surfaces. The anodic polarization curves predicted that the beryllium-containing nickel alloy should be susceptible to localized corrosion and SEM revealed an etched surface with corrosion of certain microstructural features. No significant corrosion was predicted or observed for the non-beryllium nickel alloy and the gold alloy. The in vitro corrosion evaluations predicted the in vivo corrosion behavior for the alloys. Since the three copper alloys and the beryllium-containing nickel alloy demonstrated significant corrosion under the tested conditions, the use of these alloys for restorative procedures is questionable due to the release of significant levels of selected ions to the oral cavity.

The galvanic currents between amalgam and gold alloy electrodes were higher in saline solutions than in saliva. Conventional amalgam supported higher currents than high copper amalgams when short-circuited with a gold alloy. The galvanic currents were not affected or affected only to a very small degree when whole saliva from different persons were compared. Higher currents were recorded when short-circuiting conventional amalgam and gold alloy electrodes using parotid saliva than when using whole saliva collected from one person. However, removing molecules with a molecular weight higher than 10(4) from whole and parotid saliva did not seem to affect the galvanic currents.

Short-circuited electrodes of dental amalgams and a gold alloy were used in an attempt to study a possible relationship between the quantity of copper and tin ions released into an electrolyte and the charge transferred between the electrodes. It was found that under the experimental conditions used the quantity of tin ions released was related to the charge transferred between the conventional amalgam and the gold alloy. The same tendency was found using a saliva sample which confined and collected the released tin ions into a small volume when the conventional amalgam specimen was short-circuited to the gold alloy specimen in vivo.

The purpose of this investigation was to study the tarnish and corrosion of three commercial copper alloys, three experimental copper alloys, two nickel alloys, and one high-gold alloy by exposing the specimens for four weeks to artificial saliva and saline solutions. Half of the specimens were brushed, and the solutions were changed regularly. The copper-based and the beryllium-containing nickel alloys exhibited significant surface alterations after exposure to either solution. The potential of elevated release of ions to the oral cavity and to the target organs by some of the investigated alloys should be considered if dental usage of these alloys is to be extended.