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PubMed1984

Relief formation in polished amalgam surfaces.

The relief produced in the surface of dental amalgam as a result of polishing was studied by scanning electron microscopy in traditional low-copper amalgams, high-copper dispersant-type amalgams, and high-copper single-composition amalgams. Specimens were polished metallographically in two planes at right angles to each other. Micrographs were taken of the edge between the planes; the profile of one of the polished planes could be traced and the microstructural phases recognized. The traced lines were analyzed by a computer that calculated the mean levels of the phases and the mean deviation (roughness) of all the phases along the scanned distance. Recesses were seen in the surface of the gamma-2 phase. The gamma-1 phase attained the highest level, protruding above the phases of the alloy particles. The results indicate that well-polished amalgam surfaces have a structural relief that contributes to the roughness and limits the degree of smoothness that can be obtained in an amalgam surface.

Dental Amalgam↗
PubMed2000

Some results on Hg content in hair in different populations in Albania.

The mercury content in hair, for exposed dental workers and unexposed groups of people living in Albania was studied. The influence of factors such as age, sex, body weight, fish consumption in the diet, number of dental amalgam fillings and time exposed to mercury, was determined. The mean value of mercury content in hair for the subjects under study (0.705 microg/g) was found to be lower than the value referred from the World Health Organization (WHO) for people who do not consume fish with a high methylmercury content (1-2 microg/g). A significant positive correlation of Hg content with the number of dental amalgam fillings, time under exposure and frequency of fish consumption in the diet was found. These correlations became stronger when exposed and unexposed groups of people were evaluated separately.

Adult↗
PubMed2001

Metal exposure from amalgam alters the distribution of trace elements in blood cells and plasma.

Twenty-seven consecutive patients with health problems associated with dental amalgam were recruited. In spite of thorough medical examinations, there were no diagnoses available. The patient group was dominated by women. A healthy age- and sex-matched control group with dental amalgams without symptoms was also recruited. Metal level monitoring in plasma and nuclear microscopy of isolated individual blood cells were carried out. Significant increases of copper, iron, zinc and strontium were found in patient plasma. There was no significant difference in plasma selenium between the groups. Mercury was significantly increased in patient plasma, although there was overlap between the groups. In erythrocytes a significant increase in calcium and a significant decrease in magnesium, copper, manganese and zinc were found. Calcium, magnesium, manganese and copper increased in patient neutrophil granulocytes. A significant decrease was found for zinc. A conspicuous finding was the presence of measurable mercury in a few of the cells from the patient but not in the control group. Thus, nuclear microscopy of isolated individual blood cells might provide a better diagnostic tool for metal exposure than blood plasma measurements.

Adult↗
PubMed2000

Risk of respiratory exposure of dental personnel to amalgam alternatives.

Although the use of alternatives to dental amalgam is increasing, the possible hazard associated with their occupational exposure has received inadequate attention. The purpose of this study is to use available toxicological and environmental information in a qualitative risk assessment to address potential health hazards associated with exposure to these materials by dental personnel. The members of dental profession should be aware of risk due to long-term exposure to dental materials.

Dental Amalgam↗
PubMed1994

Description of persons with symptoms presumed to be caused by electricity or visual display units--oral aspects.

A questionnaire containing 20 questions was sent to 127 members of the Association for Those Injured by Electricity and Visual Display Units in northern Sweden, of whom 103 (81%) answered. The questionnaire consisted of questions about age, sex, and place of work. Furthermore, the members were asked to state: 1) their general and oral symptoms; 2) whether they thought that dental amalgam and other types of dental filling materials had affected their symptoms; 3) whether they were replacing or had replaced their amalgam fillings and, if so, what effect it had had on their symptoms; 4) whether they had been medically examined; and 5) whether they were or had been sick-listed for their complaints. Of those who answered the questionnaire, 79% were women (mean age 45 yr) and 21% men (mean age 42 yr). Sixty percent worked in offices. In 82%, the symptoms had started at work. The mean duration of the symptoms was 5.2 yr. The symptoms were aggravated mostly in "electric environment in general" and in "office with computers". Skin complaints, fatigue, and eye symptoms were the most common general symptoms. Sixty-five percent mentioned that they had oral symptoms. Gustatory disturbances, burning mouth, and temporomandibular joint (TMJ) dysfunction were the most common oral symptoms. Fifty-six percent considered that dental amalgam and 24% that other dental materials affected the symptoms. Twenty-one percent were in the process of replacing the amalgam fillings; 40% had already done so. After replacement, 37% had noticed a decrease of symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2004

Are there acceptable alternatives to amalgam?

Amalgam has been the material of choice for restoring posterior teeth for more than 100 years. The past 25 years have witnessed significant advances in restorative materials themselves and in the bonding systems for retaining a restoration in the prepared tooth. As a result, there has been a shift toward resin composite materials during this same period because of concerns about the esthetics and biocompatibility of dental amalgam. In addition, other materials such as glass ionomer cements, ceramic inlays and onlays, and gold alloys have been used as alternatives to amalgam. This article will review recent studies on the longevity and biocompatibility of these alternatives to dental amalgam.

Biocompatible Materials↗
PubMed1975

Six-month and one-year clinical evaluation of a composite resin for class II restorations.

This clinical study was undertaken to compare a composite resin, containing a modified filler, with a dental amalgam alloy in Class II restorations. Eight senior dental students placed 98 pairs of restoration in 69 patients. After six months and one-year, 69 pairs of restorations in 49 patients were evaluated by two examiners. No significant differences were found between baseline and one-year evaluations for ratings of anatomic form and marginal adaptation. Color match was found to decrease in time, and marginal discoloration was found to increase in time. Failures of restoration were not attributed to the materials, but more probably were caused by faulty cavity preparations. Although the results for each patient analysis indicated no significant differences in anatomic form and marginal adaptation at one year, the B ratings for these two criteria for both types of restorations in this study indicate the need for continued clinical evaluation. The decreased number of composite restorations with good color match is not unexpected and indicates the need for judgment when selecting composite resin as the restorative material in Class II preparations for esthetic purposes. The significant number of composite restoration in this study with increasing marginal discoloration is reason for concern and continued evaluation of these restorations. Marginal discoloration and poor marginal adaptation are factors related to recurrent caries and replacement of restorations. Thus, continued research and clinical evaluation of new restorative materials is a necessity.

Color↗
PubMedDate not supplied

[An amalgam mixer for dental work].

A stomatologic amalgam mixer with an automated dosage device ACD-02 is destined for measuring the powdered alloy of silver and mercury out, preparation of amalgams from the mentioned components or filling material "Gallodent-M" in conditions of stomatological polyclinics. Constant mixture of powder layers in the scale body reservoir and immediate measuring out the powdered alloy on switching on the electric drive are provided. The apparatus is completed by a cup with a forked holder and a special reusable capsule for manufacture of filling material "Gallodent-M".

Dental Amalgam↗
PubMedDate not supplied

[Functional dental anatomy and amalgam].

Very often, the functional dental anatomy are reflected during the rehabilitation of posterior quadrants. However, the placement, the shaping in correct relation of the different dental components are indispensable conditions to respect, in order to achieve an adequate integration of the restoration within the neuro-muscular system. A clinical protocol is proposed in order to reconcile the anatomical and biological prerequisite and the setting time of modern alloys.

Dental Amalgam↗
PubMed1981

[Corrosion behavior of high copper amalgam (author's transl)].

In this paper, the experiments have been carried out to find the effects of additional copper and to find a correlation between the microstructure and the electrochemical behavior of dental amalgam. The corrosion behavior of high copper amalgam has been investigated by potentiostatic anodic polarization in 0.9% NaCl solution and compared with conventional dental amalgam. High copper amalgam become appreciably more noble (potential shift from -0.15 V to 0.5 approximately 0.8 V vs SCE). Such a behavior has been explained in terms of the solid state transformation which involves the elimination of the corrosion prone gamma 2 phase and the conversion of an electrochemically Cu6Sn5 intermetallic to a noble Cu3Sn.

Copper↗
PubMed2000

Delayed and immediate hypersensitivity reactions associated with the use of amalgam.

Hypersensitivity to the constituents of dental amalgam is uncommon. When it occurs it typically manifests itself as a lichenoid reaction involving a delayed, type IV, cell-mediated hypersensitivity response. Rarely, a more acute and generalised response can occur involving both the oral mucosa and skin. We describe two cases that illustrate the presentation and management of these two types of reaction.

Blister↗
PubMed1999

Amalgam allergy associated with exacerbation of aspirin-intolerant asthma.

BACKGROUND: Aspirin-intolerant asthma can be induced not only by acidic analgesics (including acetylsalicylic acid), which effectively inhibit cyclo-oxygenase, but also by cross-reactivity with paraben, and other chemical additives. OBJECTIVE: We examined whether amalgam allergy is involved in the pathogenesis of a aspirin-intolerant asthma. METHODS: We present the first case of aspirin-intolerant asthma that improved after the removal of dental amalgam. In addition, we performed both the methacholine provocation testing and sulpyrine provocation testing before and after the removal of dental amalgam. RESULTS: In addition, the methacholine concentration causing a 20% fall in FEV1 in provocation tests rose significantly, though hypersensitivity to analgesics evaluated with sulpyrine provocation testing did not decrease. These results suggest that amalgam sensitization is involved in bronchial hyperresponsiveness in aspirin-intolerant asthma. CONCLUSION: Sensitivity to amalgam may cause exacerbation of aspirin-intolerant asthma in some patients. To the best of our knowledge, this is the first case report of amalgam allergy associated with aspirin-intolerant asthma.

Adult↗
PubMed2000

Relation between mercury concentrations in saliva, blood, and urine in subjects with amalgam restorations.

The aim was to determine the relationship between mercury content of resting and stimulated saliva, and blood and urine. Eighty subjects participated; 40 of them attributed their self-reported complaints to dental amalgam (patients), the others were matched with respect to age, sex and amalgam restorations (controls). Serum, 24-h urine, resting and chewing stimulated saliva were analyzed for mercury using the ASS-technique. Quality, number, surfaces and total area of amalgam fillings were recorded clinically and using study models. Median (range) mercury levels in serum were 0.67 (0.1-1.52) microgram/l for patients and 0.60 (0.1-1.3) for controls. In urine levels were found to be 0.77 (0.11-5.16) and 0.94 (0.17-3.01) microgram/g creatinine respectively. No significant differences were found between the groups. Resting saliva contained 2.97 (0.10-45.46) micrograms/l in patients and 3.69 (0.34-55.41) in controls (not significant). Chewing mobilized an additional amount of 16.78 (-6.97 to 149.78) micrograms/l in patients and 49.49 (-1.36 to 504.63) in controls (P < or = 0.01). Only a weak correlation was found between mobilized mercury in saliva and serum (r = 0.27; P < or = 0.05) or urine (r = 0.47; P < or = 0.001). For resting saliva the respective values were r = 0.45 (P < or = 0.001) and r = 0.60 (P < or = 0.001). Saliva testing is not an appropriate measure for estimating the mercury burden derived from dental amalgam.

Adult↗
PubMedDate not supplied

Observation of an amalgam-bonded tooth through a scanning electron microscope.

Bonding dental amalgam to tooth reduces the occurrence of marginal leakage, fracture and sensitivity. However, most studies of amalgam bonding have made use of resin cements and the conventional three-bottle bonding agents. In this study, a newer, single-bottle bonding agent was used to bond amalgam both to dentin and enamel. Interfaces of bonded amalgam and unbonded amalgam were observed under the scanning electron microscope.

Bicuspid↗
PubMed1993

Mercury and selenium in workers previously exposed to mercury vapour at a chloralkali plant.

The concentrations of total mercury (B-Hg), inorganic mercury (B-IHg), and methyl mercury (B-MeHg) in whole blood, urinary mercury (U-Hg), and selenium in urine (U-Se) and whole blood (B-Se) were determined in 74 chloralkali workers previously exposed to Hg vapour, and compared with 51 age matched referents. Dental amalgam state, fish consumption, and exposure related indices were studied with regard to the determined elements. A significant relation between the surface of dental amalgam and U-Hg (Pearson's r = 0.63, p < 0.001) was found among the referents. Mean U-Se was significantly lower (p < 0.001) among the subjects previously exposed to Hg (34.1 nmol/mmol creatinine) compared with that for the referents (42.6 nmol/mmol creatinine). A significant negative relation between the cumulative Hg dose and U-Se was also found. The mechanisms and the clinical significance of these findings are not clear. No relation between current U-Hg and previous occupational exposure to Hg was found among subjects in whom exposure had ceased more than one year before the study.

Adult↗
PubMed1999

A two-year randomized, controlled clinical evaluation of bonded amalgam restorations.

PURPOSE: The clinical performance of adhesively bonded dental amalgam restorations was compared with that of traditionally placed non-bonded control amalgams in a randomized prospective study. MATERIALS AND METHODS: One-hundred thirteen Class II Dispersalloy amalgams were placed in permanent molars and premolars of 31 (21 males, 10 females) human subjects with their informed consent. By random assignment, 60 amalgam restorations were adhesively bonded using ED Primer and Panavia 21 TC (both Kuraray Co, Japan), and 53 traditional non-bonded restorations were placed. Most preparations involved replacement of defective amalgam restorations. Clinical recalls were conducted by experienced evaluators using modified USPHS criteria for occlusal and proximal anatomic form, occlusal and proximal marginal adaptation, and occlusal and proximal surface roughness. RESULTS: For the categories of anatomic form, marginal adaptation, surface quality, and temperature sensitivity, there were no significant differences between bonded and non-bonded amalgam restorations (chi-square analysis, p > 0.05). Three non-bonded restorations were lost at 4, 7, and 24 months from preparations with no deliberate retention. CONCLUSION: After two years' clinical service, there were no failures among the amalgam restorations adhesively bonded using ED Primer and Panavia 21 TC, but three non-bonded restorations failed due to lack of retention. For traditional preparations, adhesively bonded amalgams of the type investigated perform as well as non-bonded amalgams over two years' clinical service.

Bicuspid↗
PubMed1992

Corrosion testing by potentiodynamic polarization in various electrolytes.

The effect of different electrolytes on the results from potentiodynamic polarization corrosion testing was studied for nine different dental alloys. In general, the difference in the results was greater between certain alloys using the same electrolyte than between the electrolytes with the same alloy. However, there were some differences between the electrolytes, most pronounced when testing dental amalgams. The electrolyte consisting of 1% NaCl seemed to offer the most corrosive environment. Darvell's and Fusayama's solutions were much less corrosive, at least for dental amalgam specimens. With regard to the ranking by corrosion sensitivity of the amalgams, only the results obtained by using Fusayama's solution were consistent with the clinical experience of the materials.

Analysis of Variance↗