[The reactions of lipid's free radical oxidation, hemocoagulant properties of oral fluid in patients with galvanic currents in the mouth].

OBJECTIVE: Introduction: Oral manifestation of galvanic currents due to the presence of two and more dissimilar metals in dental restorations is rather important in prosthodontics. The aim of our study was to assess the reactions lipid's free radical oxidation and hemocoagulant properties of oral fluid in patients with disorders in oral cavity due to galvanic currents. PATIENTS AND METHODS: Materials and methods: The study had got some groups. The first one consisted of 7 healthy patients without dental prosthesis. The other one included 22 patients with dental prosthesis and they were suffered from short circuiting due dissimilar metallic restorations in oral cavity. This group we were divided into two groups: the second one - for 7 patients were produced metal ceramic fixed dental prosthesis, the third one - for 15 patients were produced whole casted fixed dental prosthesis and pressing brazed fixed dental prosthesis. To assess the process of lipid's free radical oxidation of oral fluid we studied kinetic concentration of malone dialdehyde, activity level of superoxide dismutase and catalase. Also we found out hemocoagulant activity data of oral fluid: thrombin time, prothrombin time, fibrinolytic activity, recalcification time. RESULTS: Results: In our study we observed increasing of lipid's free radical oxidation in patients of the second and third groups, which led to increasing malone dialdehyde data in third group compared with second group. In patients of second and third groups was recorded the increasing of the CAT activity in the oral fluid. Also there is the in fact decreasing in hemocoagulant properties of oral fluid, such as reducing in recalcification time, increasing in prothrombin time in the second and especially in the third groups of patients. It was marked the significant increasing of fibrinolytic activity of oral fluid in the second and third group of patients. CONCLUSION: Conclusions: The oral manifestation of electrochemical interactions due to presence of dissimilar metallic restorations led to shift in oral cavity's homeostasis. This statement we can verify with results of our study. In patients with oral manifestation of galvanic currents were observed the increasing in activity of the reactions of lipid's free radical oxidation in oral fluid, changes in antioxidative enzymes and in local homeostasis of oral fluid.

Galvanic coupling of steel and gold alloy lingual brackets with orthodontic wires: Is corrosion a concern?

OBJECTIVES: The aim of this research was to assess galvanic behavior of lingual orthodontic brackets coupled with representative types of orthodontic wires. MATERIALS AND METHODS: Three types of lingual brackets: Incognito (INC), In-Ovation L (IOV), and STb (STB) were combined with a stainless steel (SS) and a nickel-titanium (NiTi) orthodontic archwire. All materials were initially investigated by scanning electron microscopy / x-ray energy dispersive spectroscopy (SEM/EDX) while wires were also tested by x-ray diffraction spectroscopy (XRD). All bracket-wire combinations were immersed in acidic 0.1M NaCl 0.1M lactic acid and neutral NaF 0.3% (wt) electrolyte, and the potential differences were continuously recorded for 48 hours. RESULTS: The SEM/EDX analysis revealed that INC is a single-unit bracket made of a high gold (Au) alloy while IOV and STB are two-piece appliances in which the base and wing are made of SS alloys. The SS wire demonstrated austenite and martensite iron phase, while NiTi wire illustrated an intense austenite crystallographic structure with limited martensite. All bracket wire combinations showed potential differences below the threshold of galvanic corrosion (200 mV) except for INC and STB coupled with NiTi wire in NaF media. CONCLUSIONS: The electrochemical results indicate that all brackets tested demonstrated galvanic compatibility with SS wire, but fluoride treatment should be used cautiously with NiTi wires coupled with Au and SS brackets.

[Experimental base for construction alloy choice for implant-retained restorations].

The paper contains the results of experimental studies on galvanic features of "implant-construction alloy" contact pair. These results may be used as criteria for implant-retained restorations alloy choice.

Immune markers in oral discomfort patients before and after elimination of oral galvanism.

BACKGROUND: An enhanced release of metals in the mouth due to galvanic cell formation is considered to be one of the causes of oral discomfort. The aim of this study was to investigate the influence of galvanic cell on salivary immune defense factors. MATERIAL AND METHODS: The levels of IgA1, IgA2, sIgA, lysozyme and antiIgA/HSP60 were evaluated in representative samples from 159 patients with galvanism, from 177 patients without galvanism and in two control groups. All the participants underwent personal history taking, clinical examination, galvanic currents measurement and saliva collection. RESULTS: Electro active dental materials were removed in 30 patients. There was a significant increase in IgA2 level, a significant decrease in antiIgA/HSP60 levels and an increase in IgA1, sIgA and lysozyme levels found after the removal of electro active restorations. Morphological symptoms disappeared in 70% of the treated patients. CONCLUSION: The study confirmed that pathologic galvanic phenomena influences the immune defense reactions in the oral cavity and thus may cause the symptoms of oral discomfort. A measurement of the galvanism and a subsequent removal of electro active restorations should become a common therapeutic procedure in the patients with oral discomfort.

Induction of apoptosis and up-regulation of cellular proliferation in oral leukoplakia cell lines inside electric field.

OBJECTIVE: In dentistry, metallic alloys are used for dentures, restorative materials, and orthodontic devices. Electric voltages up to 950 mV may occur between different dental alloys in the oral cavity. This study aimed to investigate physiologic reactions of oral leukoplakia cells in vitro to electric fields. STUDY DESIGN: A human leukoplakia cell line (MSK-LEUK1), cultivated in keratinocyte growth medium (KGM-2) supplemented with growth factors in 5% CO(2) humidified air at 37°C, was exposed to electric field strength of 1-20 V/m for 24 hours in a custom-made pulse chamber. The cells were then analyzed for proliferation with the use of BrdU assay and for apoptosis with the use of TUNEL assay. Findings were assessed with the use of fluorescent microscopy. Ultrastructural changes were studied by transmission electron microscopy. RESULTS: Electric field strength of 1-10 V/m led to up-regulation of cell proliferation rate from 10.64% to 44.06% (P = .0001). The apoptotic index increased significantly (P = .0001) from 20.03% at 1 V/m to 46.56% at 10 V/m. Individual cell keratinization was seen in leukoplakia cells treated with 16 V/m. CONCLUSIONS: Oral galvanism induces subcellular changes in oral precancer cells in vitro that closely simulate some of the morphologic features of oral squamous cell carcinoma cells in vivo.

Dental and periodontal complications of lip and tongue piercing: prevalence and influencing factors.

BACKGROUND: The aim of this study was to compare the prevalence of lip and tongue piercing complications and explore the effect of ornament time wear period, habits, ornament morphology and periodontal biotype on the development of complications. METHODS: One hundred and ten subjects with 110 lip and 51 tongue piercings were assessed for abnormal toothwear and/or tooth chipping/cracking (dental defects), gingival recession, clinical attachment loss and probing depth of teeth adjacent to the pierced site. Piercing habits (biting, rolling, stroking, sucking) were recorded. RESULTS: Wear time and habits significantly affected the prevalence of dental defects and gingival recession. Pierced site significantly affected dental defects prevalence, with greater prevalence for tongue than lip piercing. Wear time significantly affected attachment loss and probing depth. Attachment loss and probing depth did not significantly differ between tongue and lip piercings. Gingival recession was significantly associated with ornament height closure and stem length of tongue ornaments. Periodontal biotype was not significantly associated with gingival recession, attachment loss and probing depth. CONCLUSIONS: Dental defects prevalence is greater for tongue than lip piercing. Gingival recession is similar for tongue and lip piercing. Longer wear time of tongue and lip piercing is associated with greater prevalence of dental defects and gingival recession, as well as greater attachment loss and probing depth of teeth adjacent to pierced sites. Ornament morphology affects gingival recession prevalence.

The change of electric potentials in the oral cavity after application of extremely low frequency pulsed magnetic field.

Electric potentials occurring in the oral cavity deserve attention as they may cause various diseases and subjective feelings, which are very difficult to treat. The aim of this study was to evaluate the electric potentials within the oral cavity in patients with metal fillings and metal prosthetic restorations, after using a pulsed electromagnetic field. The study was carried out on 84 patients. The Viofor JPS Classic device was used in the treatment. It generates a pulsed electromagnetic field with low induction of the extremely low frequency (ELF) range. Average values of electric potentials in the preliminary test were about the same in both groups; they were 148.8 mV and 145.5 mV. After another appliance of ELF fields there was found a steady decline in the average value of electric potentials in the study group. This decrease was statistically highly significant, while mean values of electric potentials in the control group were characterized by a slightly upward tendency. The obtained statistically significant reduction of electric potentials in the oral cavity of patients having metal fillings and metal prosthetic restorations, after application of the Viofor JPS Classic device, implies a huge impact of ELF pulsed electromagnetic field on inhibition of electrochemical processes, as well as on inhibition of dental alloy corrosion. 

[The center of pathological (toxic) action of metals in an people organisms and a role of galvanic currents in its induction].

Chronic influence of metals on an organism differs from their sharp toxic action. In some exposed to long chronic metals influence people appear chronic inflammatory diseases, including oncological, on a background of neurologic symptoms develop. Today the overwhelming majority of the population is more 40-50 years old have metal alloys in the form of dental artificial limbs and various implantates in a body. Because of metal corrosion in organisms of these people concentration of metal ions is created. Galvanic currents induced at presence of any metals in an organism, promote corrosion, and carry of metal ions inside organism. If these currents are strong (the potential difference more 150 MB), local inflammatory pathologies development in organism due to concentration in the center of metal ions.

Galvanic corrosion between various combinations of orthodontic brackets and archwires.

INTRODUCTION: The purpose of this study was to compare galvanic currents generated by different combinations of commonly used brackets and archwires. METHODS: As-received stainless steel, nickel-titanium, and beta-titanium wires were coupled to stainless steel and titanium brackets in an artificial saliva medium. The galvanic current and amount of charge transferred for each pair were monitored with a zero resistance ammeter for 10 hours. RESULTS: Two-way analysis of variance (ANOVA) showed a significant difference in charge and galvanic currents when factored for type of bracket (P <0.001), but no significant difference between them when factored by type of wire (P >0.05). Specifically, a brazed stainless steel bracket was significantly greater in charge transferred and 10-hour galvanic current than metal injection molded stainless steel and titanium brackets (P <0.001), which were not different from each other (P >0.05). CONCLUSIONS: The method of bracket manufacturing might be of equal or more relevance to galvanic corrosion susceptibility than bracket composition.

Rehabilitación protésica mediante sobre dentadura implanto soportada con sistema de galvano formación. A propósito de un caso / Prosthetic rehabilitation by over denture implant-supported with galvano-formation system. On the subject of an specific case

Mujer de 65 años que acude a la clínica del Máster de Prótesis Bucofacial de la Facultad de Odontología de la UCM para ser rehabilitada protésicamente tras haberse sometido a la fase quirúrgica de un tratamiento con implantes. En la exploración intraoral observamos 6 implantes maxilares que presentan una posición protésica y disparalelismos no compatible con la realización de un tratamiento estándar con prótesis fija sobre implantes. Además, se pone de manifiesto, la necesidad para poder llegar aun correcto resultado estético, de la restitución de un importante volumen de tejidos duros y blandos. La conjunción de estos factores, sumado a la importancia de proveer a la paciente de una prótesis con posibilidad de mantener un correcto estado de higiene, desaconsejan, la realización de una prótesis fija, ya sea mediante estructuras cementadas como atornilladas, tanto en metal cerámica, como en metal resina. En estos casos, la realización de una sobre dentadura implanto soportada mediante sistemas de fricción de alta precisión (microfresados y cofias realizadas mediante procedimientos de galvano formación)permite la perfecta resolución estética e higiénica del caso, sin menoscavar la sensación de "prótesis fija" por parte de la paciente (AU)

A 65 years old woman goes to the clinic of the Bucofacial Prosthesis Master of the Odontology Faculty of the UCM to be prosthetically rehabilitated after having been operated of an implant treatment. In the intraoral exploration we observe 6 maxillary implants presenting a prosthetic positions and disparallelisms non-compatible with the execution of a standard treatment with fixed prosthesis on implants. Moreover, the need to restore a significant volume of hard and soft tissues for a correct a esthetical result becomes evident. All these factors, also considering the importance to provide the patient with a prosthesis to allow her a correct hygiene condition, advises against the execution of a fixed prosthesis, either by means of cemented or screwed structures, both in metal ceramic or metal resin. In these cases, the execution of an overdenture implant supported by means of high-precision friction systems (micromilled and cauls made by galvano-formation proceedings) allows the perfect a esthetical and hygienic resolution of the case without diminishing the sensation of “fixed prosthesis” by the patient (AU)

Niveles de bioelectricidad en amalgamas con y sin base intermedia / Bio-electricity levels in amalgam fillings with or without intermediate base

Los nuevos materiales estéticos no han ocasionado el abandono de las obturaciones de amalgama, es por eso que es importante proponer elementos que le den longevidad a las restauraciones. El propósito de este estudio fue determinar la relación entre los niveles de bioelectricidad y la presencia de base intermedia en obturaciones de amalgama. El presente estudio es un diseño de tipo descriptivo transversal, la población de estudio se conformó por un total de 30 de obturaciones de pacientes que fueron atendidos en la Clínica Odontológica de la Universidad Cooperativa de Colombia de la ciudad de Pasto en el segundo semestre académico del 2007. Los niveles de bioelectricidad se midieron en microamperios con un tester Techma TM-086 en sensibilidad de 20 uA. El mayor promedio de bioelectricidad lo generaron las restauraciones de amalgama que no presentaron base intermedia con un promedio de 0,02867 UA (Mann-Whitney- p=0.031) con respecto a las que tenían base intermedia con un promedio de -0.07133uA y la marca de amalgama que más bioelectricidad generó fue la New Stetic con un promedio de 0,01535 uA (Kruskal wallis - p=0.008) con respecto a SDI con un promedio de -0.16633 uA y Kerr con un promedio de -0.0998 uA. La intensidad del pasaje de corriente disminuye en las obturaciones de amalgamas cuando presentan base intermedia.

An overview of the corrosion aspect of dental implants (titanium and its alloys).

Titanium and its alloys are used in dentistry for implants because of its unique combination of chemical, physical, and biological properties. They are used in dentistry in cast and wrought form. The long term presence of corrosion reaction products and ongoing corrosion lead to fractures of the alloy-abutment interface, abutment, or implant body. The combination of stress, corrosion, and bacteria contribute to implant failure. This article highlights a review of the various aspects of corrosion and biocompatibility of dental titanium implants as well as suprastructures. This knowledge will also be helpful in exploring possible research strategies for probing the biological properties of materials.

[Saliva pH and galvanic current ways in mouth tissues and liquids].

In the group of 290 human having metal artificial limbs in an oral cavity, decrease in average value pH the mixed saliva in comparison with the persons who are not having metal inclusions was due to increase of percent of persons with sour reaction of saliva. Thus the degree of decrease the mixed saliva pH did not depend up on size of galvanic currents and presence of galvanic symptoms. The hypothesis was put forward, that decrease of saliva pH and development of galvanism was connected with local changes in a biofilm contacting to metal artificial prosthetic devices. Galvanic currents extended both on a surface of oral mucous membrane and in tissue. Clinical symptoms of galvanism we more expressed when galvanic currents flow manly in oral tissue.

Separating oral burning from burning mouth syndrome: unravelling a diagnostic enigma.

Burning mouth syndrome (BMS) is characterized by burning pain in the tongue or other oral mucous membrane often associated with symptoms such as subjective dryness of the mouth, paraesthesia and altered taste for which no medical or dental cause can be found. The difficulty in diagnosing BMS lies in excluding known causes of oral burning. A pragmatic approach in clarifying this issue is to divide patients into either primary (essential/idiopathic) BMS, whereby other disease is not evident or secondary BMS, where oral burning is explained by a clinical abnormality. The purpose of this article was to provide the practitioner with an understanding of the local, systemic and psychosocial factors which may be responsible for oral burning associated with secondary BMS, therefore providing a foundation for diagnosing primary BMS.

Effect of surface area ratios and bacteria on electrochemical behavior of galvanically coupled titanium.

PURPOSE: This study aimed to investigate the electrochemical behavior of commercially pure titanium (grade II) coupled with type IV gold alloy and nickel-chromium alloy at different surface area ratios in 3 different electrolytes. MATERIALS AND METHODS: Titanium was coupled with gold (Ti/Au) and nickel-chromium (Ti/Ni-Cr). For each couple, 9 surface area ratios between titanium and gold or nickel-chromium were prepared. The electrolytes used were 1% lactic acid, tryptic soy broth media, and Streptococcus mutans culture supernatant. The corrosion polarization curves were obtained, and average values of corrosion potential and corrosion current density were calculated. RESULTS: Both Ti/Au and Ti/Ni-Cr were affected by surface area ratios and different electrolytes, showing the least corrosion rate when the ratio was 1:1 and when the lactic acid was used as an electrolyte. CONCLUSIONS: The greater the difference in surface area between titanium and restorative materials, the more corrosive behavior the materials show. The existence of bacteria such as S mutans may aggravate corrosive behavior between different metals.

Corrosion of orthodontic appliances--should we care?

Contemporary orthodontics relies on various bonded attachments, archwires, and other devices to achieve tooth movement. These components are composed of varying materials with their own distinctive physical and mechanical properties. The demands made on them are complex because they are placed under many stresses in the oral environment. These include immersion in saliva and ingested fluids, temperature fluctuations, and masticatory and appliance loading. The combination of these materials in close proximity and in hostile conditions can result in corrosion. Our purpose in this article was to consider the literature to date with regard to potential mechanical, clinical, and health implications of orthodontic corrosion.

Existence of an electrically insulating layer in amalgam-containing galvanic couples.

OBJECTIVE: Avoiding the placement of amalgam and noble metal restorations in interproximal contact is recommended due to anticipated galvanic corrosion of the amalgam. There is a similar concern for amalgam/amalgam galvanic couples. It was the objective of this study to determine if an electrically insulating layer forms in the contact area of these galvanic couples. The existence of an electrically insulating layer, which could reduce the galvanic corrosion rate, would be indicated by different corrosion potentials for the two restorations of the couple. METHODS: Using a convenience sample of 158 human subjects, corrosion potentials were measured on each restoration of three types of galvanic couples: amalgam/noble metal (n=8), amalgam/amalgam (n=93) and noble metal/noble metal (n=7). Measurements were made with a Ag/AgCl micro-reference electrode and a high impedance voltmeter. All restorations were at least 6 months old. RESULTS: Statistical analysis showed that the mean absolute corrosion potential differences and the simultaneous confidence intervals of the couples were, respectively, amalgam/noble metal: 62 (31)mV and (27, 99)mV, amalgam/amalgam: 11 (14)mV and (7, 15)mV and noble metal/noble metal: 7 (10)mV and (0, 19)mV. SIGNIFICANCE: The amalgam/noble metal couples had consistent and mostly large corrosion potential differences between their restorations, which indicated the presence of an electrically insulating layer. An electrically insulating layer was also indicated for the amalgam/amalgam and noble metal/noble metal couples. The layer is probably composed of non-metallic corrosion products, biofilms, and possibly, dental calculus, which could reduce galvanic corrosion rates to small or negligible values.

Fabrication of zirconium primary copings to provide retention for a mandibular telescopic overdenture: a clinical report.

Because of their strength, zirconia ceramics may be used to restore removable partial denture abutments. This carries the advantages of elimination of the galvanic current between primary and secondary copings, along with thermal protection of abutment teeth. This article describes the fabrication of zirconium primary copings to provide retention for a mandibular telescopic overdenture.