• International Journal of Oral Biology
• /
• v.36 no.3
• /
• pp.123-128
• /
• 2011

The notion that dental amalgam is a potential source of mercury exposure remains a controversial issue. However, there are few epidemiological analyses that have addressed whether this occurs in children. We aimed in our current study to identify the relationship between dental amalgam filling surfaces and the blood mercury levels in a cohort of 711 South Korean children aged between 8-9 years. Oral examinations were conducted to detect the number of amalgam filling surfaces on the teeth of these individuals. Blood samples were also taken from these children to assess the levels of mercury accumulation in the body. The amalgam filling surfaces were classified into four groups based on their number: 0 (n = 368), 1-5 (n = 219), 6-10 (n = 89), and 11+ (n = 35). The blood mercury levels in the children with more than 10 amalgam surfaces was 0.47 ${\mu}g$/L higher on average than those with no amalgam surfaces after adjusting for the frequency of fish or seafood consumption, age, and gender (P < 0.05). We found from our data that a higher number of dental amalgam fillings correlated with a higher blood mercury level in Korean children. Further studies are needed to investigate whether these elevated mercury levels exert neurotoxic or nephrotoxic effects.

• Restorative Dentistry and Endodontics
• /
• v.19 no.1
• /
• pp.217-230
• /
• 1994

The purpose of this study was to assess the 24-hour shear bond strength of amalgam to glass ionomer cement, using five different intermediaries. The intermediaries used in this study were Scotchbond 2 (light curing dentin adhesive), Panavia (resin cement), liquid' of glass ionomer cement (chemical curing & light curing), and uncured mixture of light curing glass ionomer cement. This study was operated with 48 specimens devided into 6 groups. The experimental groups are as follows: Group 1 : Bonded Amalgam to chemical curing glass ionomer cement with liquid of chemical curing glass ionomer. Group 2 : Bonded Amalgam to light curing glass ionomer cement with liquid of chemical curing glass ionomer. Group 3: Bonded Amalgam to light curing glass ionomer cement with resin cement. Group 4: Bonded Amalgam to light curing glass ionomer cement with light curing dentin adhesive. Group 5: Bonded Amdlgam to light curing glass ionomer cement with liquid of light curing glass ionomer. Group 6: Bonded Amalgam to light curing glass ionomer cement with uncured mixture of light curing glass ionomer cement. 30 minutes after amalgam condensation, all specimens were stored for 24 hours in water at $37^{\circ}C$ and tested with Instron (1122). The following results obtained: 1. The shear bond strength of group 6 was higher than those of the other groups (46.7 kgf/$cm^2$, p<0.05). 2. The shear bond strength of resin cement intermediary group was lower than that of the group using uncured mixture of light curing glass ionomer cement. 3. The results of group 1 and group 2 were different, even though the inter-me diaries used were same. 4. Intermediary of Group 5 did not show complete set in Scanning Electromicroscopic examination. 5. Light-curing dentin adhesive did not show any bonding ability to amalgam.

• Journal of Yeungnam Medical Science
• /
• v.40 no.4
• /
• pp.373-380
• /
• 2023

Background: The association between dental amalgam fillings and urine mercury concentrations was investigated in this study to assess the health risks associated with dental amalgams. Methods: This cross-sectional study included 99 women in their 20s who visited the dental clinic in Daegu, Korea. The 99 participants were composed of 68 subjects who had dental amalgam fillings (exposure group) and 31 subjects who did not have dental amalgam fillings (nonexposure group). Oral examinations were conducted by a single dental hygienist, sociodemographic features were investigated as confounding variables, and urine mercury concentrations were measured using an automatic mercury analyzer. Results: The mean±standard deviation of the urine mercury concentrations of the exposure and nonexposure groups were 1.50±1.78 ㎍/g creatinine and 0.53±0.63 ㎍/g creatinine, respectively. The exposure group showed significantly higher levels than the nonexposure group (p<0.01). The urine mercury concentration significantly increased with an increase in the number of teeth filled with amalgam, cavity surfaces involved, and number of defective amalgam fillings, and according to the latest exposure time (p<0.001). In the multiple regression analysis of amalgam-related factors and urine mercury concentrations after correction for confounding factors, the urine mercury concentration in the group with six or more amalgam-filled teeth, 11 or more cavity surfaces, and two or more defective amalgams was significantly higher than that in the nonexposure group (p<0.001). Conclusion: According to this study, exposure to dental amalgams was confirmed to significantly affect urine mercury concentrations.

• Restorative Dentistry and Endodontics
• /
• v.16 no.1
• /
• pp.158-166
• /
• 1991

In order to investigate the cytotoxicity of composite resin in vitro, BALB / C mouse fibroblast were cultured in MEM in which silux, P-50, microrest, clearfil, amalgam and glass - ionomer, in shape of $2{\times}9mm$ circular disk. The experiments were- performed by cell count on 4 hours, 1, 3, 6 days and the composite resin groups, amalgam, glass - ionomer were compared. 1. On the sixth day, the cellular number of resin composite groups were remarkedly reduced, in contrast, the that of amalgam and glass - ionomer group continuously increased. 2. It was only on the 4 hours that the cellular number contained in amalgam were reduced, but increased thereafter, and the cellular number contained in glass - ionomer are greater than other groups. 3. In resin group, especially between self - curing resin and light - curing resin, there is no difference in cellular number statistically (p>0.05). 4. It was amalgam where the round cell without cellular process was found on the 4. hours and on the 6 th day the cell without cellular process was found numeroulsy in resin group whereas in amalgam and glass - ionomer, like control group was contained cell forming monolayer. These result suggested that the toxicity of the self - curing and light - curing resin greater than that of the amalgam and glass - ionomer.

• Restorative Dentistry and Endodontics
• /
• v.8 no.1
• /
• pp.89-96
• /
• 1982

The purpose of this study is to identify the phases of four different types, low-copper lathe cut (Type II, class 1) and spherical (Type II, class 2) amalgam alloys which are made by Caulk company and high copper Dispersalloy (Type II, class 3) made by Johnson & Johnson and Tytin (Type I, class 2) made by S.S. White and to determine the Vickers hardness number on the individual phase and four different types of dental amalgam. After each amalgam alloy and Hg measured exactly by the balance was triturated by the mechanical amalgamator (De Trey), the triturated mass was inserted into the cylindrical metal mold which was 4 mm in diameter and 12mm in height and was pressed by the Instron Universal Testing machine (Model 1125) at the speed of 1mm/minute with 143$kg/cm^2$ according to the A.D.A. Specification No. 1. The Specimen removed from the mold, mounted and stored in the room temperature for 7 days. The speciman was polished with the emery paper from #220 to #1200 and finally on the polishing cloth with 0.3 and 0.05 um $Al_2O_3$ powder suspended in water. And then each specimen was etched by Allan's method and washed with Sodium Bisulfinite for 30 seconds. Finally differentiation and metallography on each phase were obtained by using metallographical microscope (Versamet, Union) and microhardness was obtained by using microhardness tester (MVH-2, Torsee). The results were as follows: 1. In the low-copper amalgam, the ${\gamma}$, ${\gamma}_1$ and ${\gamma}_2$ phase were observed and in the high-copper amalgam, the ${\gamma}$, ${\gamma}_1$. ${\epsilon}$ and ${\eta}$ phases were observed but ${\gamma}_2$ phase was not observed. 2. Among the microhardness of each amalgam phase measured under pressing a vickers diamond indenter with 2.0gm load for 30 seconds, e phase has the highest V.H.N (314 ${\pm}$ 20), and in low-copper amalgam 12 phase has the lowest V.H.N. (29${\pm}$1) and ${\eta}$ phase which was observed in high-copper amalgam has 230${\pm}$13 V.H.N and this phase is considerd to contribute to strengthen the handness in amalgam. 3. The V.H.N. measured under pressing a Vickers diamond indenter with 300.0gm load for 30 seconds in low-copper amalgam was lower than that of high-copper amalgam.

• Journal of dental hygiene science
• /
• v.12 no.3
• /
• pp.253-258
• /
• 2012

Dental amalgam is an alloy composed of a mixture of approximately equal parts of elemental liquid mercury and an alloy powder. Amalgam has been the most popular and effective restorative material used in dentistry. Despite the long history and popularity of dental amalgam as a restorative material, there have been periodic concerns regarding the potential adverse health effects arising from exposure to mercury in amalgam. Since children are more at risk for mercury toxicity, we aimed to assess the association between dental amalgam filling and urinary mercury concentration in children. 581 of elementary school children in grades 1st4th were conveniently recruited from two schools located in Daegu city, Korea. To obtain dental caries experience states, oral examination were conducted using the full term for DFS index, number of amalgam filling surfaces and the type of filling materials. A questionnaire was used to collect information about general characteristics and the frequencies of tooth brushing, gum chewing and fish/seafood consumption. The statistical analysis was done using the SPSS 18.0 program. The mean urinary mercury concentration in children having more surfaces was highest. As a results Urinary mercury concentration of children who have 79 teeth of amalgam filling and more than 10 is higher than without amalgam filling. The number of amalgam filling surface is closely related with urinary mercury concentration.

• Restorative Dentistry and Endodontics
• /
• v.10 no.1
• /
• pp.153-160
• /
• 1984

The purpose of this study was to observe the tensile and bonding strength of the joined amalgam restoration. Amalgam alloys of fine-cut (F-type), spherical (S-type), and dispersed type (D-type) were selected in this study, and all specimens were divided into three groups according to the condensation methods as follows. Group I : the control group which condense the same kinds of mixed amalgam into the whole part of the mold respectively. Group II : the group which condense a mix of amalgam into one half of the mold, and then condense a new mix of amalgam into the rest half of the mold 15 minutes later. Group III : the group which condense a mixed amalgam into one half of the mold, and then condense a new mix of amalgam into the rest half of the mold 7 days later. All specimens were stored in incubator at $37{\pm}1^{\circ}C$ for seven days with immersing in saline solution before testing. The tensile and bonding strength of them were measured with Instron Universal Testing machine. The results were as follows: 1. In Group I, the order of tensile strength was F-type, S-type, and D-type. 2. In case of bonding of S-type + S-type, the difference of the bonding strength between Group II and III was not significant. (P> 0.05) 3. The bonding strength of F-type + S-type of Group II was marked the highest in value, and the lowest bonding strength was showed in bonded D-type + D-type of Group III. 4. In case of bonding with the different kinds of amalgam alloy in Group II, the specimen bonded to F-type was marked the highest bonding strength, and the specimen bonded with F-type was marked the lowest one. In Group II, the bonding strength of the specimens bonded with the same kinds of amalgam alloy was presented as the same order as that of Group I. 5. In Group III, the specimen connected with D-type marked the lowest bonding strength of all specimens. In Group III, the bonding strength of the specimens connected with the same kinds of amalgam alloy was the order of S-type + S-type, F-type + F-type, and D-type + D-type.

• Restorative Dentistry and Endodontics
• /
• v.23 no.2
• /
• pp.586-596
• /
• 1998

Amalgam is one of the most commonly used dental restoration material because of its convenience, economic and physical properties. But microleakage in the tooth and amalgam interface has been its major problem, and many efforts have been made to overcome this shortcoming. The purpose of this study is to compare the effect of various liners on microleakage of amalgam restoration. Cavities were prepared on the buccal or lingual surface of ninety sound, extracted human premolars and six different liners (Tubulitec$^{(R)}$, Superbond D-liner II Plus$^{(R)}$, Superbond D-liner II Plus$^{(R)}$ with polymer, Scotchbond Multipurpose Plus$^{(R)}$, Copalite$^{(R)}$, No liner) were unapplied according to manufacturer's instructions and amalgam had been condensed immediately. The specimens were thermocycled by dipping in methylene blue dye at $5^{\circ}C$ and $55^{\circ}C$ for 1500 cycles. The amalgam-tooth interface was examined under stereobinocular microscope and the dye penetration was scored. The results were as follows : 1. The Tubulitec$^{(R)}$ group showed less microleakage than no liner or Copalite$^{(R)}$ group (p<0.01). 2. The Tubulitec$^{(R)}$, Superbond D-liner II Plus$^{(R)}$, Superbond D-liner II Plus$^{(R)}$ with polymer and Scotch bond Multipurpose Plus$^{(R)}$ groups were not significantly different. 3. The Copalite$^{(R)}$ and Scotchbond Multipurpose Plus$^{(R)}$ groups were not significantly different. Using the polystyrene liner and resin liners under admixed type of high-copper amalgam restoration significantly reduced microleakage in the tooth-amalgam interface. Further clinical studies on polystyrene liner are recommended.

• Restorative Dentistry and Endodontics
• /
• v.6 no.1
• /
• pp.109-114
• /
• 1980

Ease of manipulation, adequate mechanical properties, long years of experience and economical cost are the factors which have established amalgam as the most widely used material for dental restorations. But amalgam restoration may require replacement because of secondary caries, fracture, "fall-out", dimensional change, tarnish or corrosion etc.. These failures of amalgam restorations seem to arise from failures during operations rather than from the inherent shortcomings of the material itself or of the patient's mismanagement. It is anticipated that notonly number of analgam restoration, but failures will be increase after more extensive utilization of the medical insurance which began in 1977. Then authors think that it would be helpful for the development of better treatment in daily dental practice, to know the duration of amalgam restorations and the reasons for their replacement. The data for this survey was compiled from 2, 856 out-patients of the Department of Dentistry, Ewha Woman's University Hospital from January 1975 to December 1977. 260 cases among 1,718 fillings were studied, of which 205 cases both had a single reason for replacement and recognized the date of the previous filling. The results obtained were as follows; 1. Amalgam fillings were 58. 5 percent of all dental restorative materials. Of these, 15. 13 percent of the amalgam restorations had to be replaced. 2. The first reason for replacement of amalgam restorations was secondary caries (56.10%), the second was fracture (23.80%) and the third was "fall-out" (8.78%). 3. Among those amalgms requiring replacement, 52.2 percent had been in place less than 3 years, 70.7 percent within 5 years and 89.8 percent had been in place less than 10 years. Only 10.2 percent had been in place more than 10 years.

• Restorative Dentistry and Endodontics
• /
• v.14 no.1
• /
• pp.199-204
• /
• 1989

The purpose of this study was to observe the anodic polarization curve from 4 kinds of low copper amalgam (Fine cut alloy, Spheralloy, Aristalloy and Amalcap) and 4 kinds of high copper amalgam (Dispersalloy, Sybraloy Orosphere and Tytin) obtained by using the potentiostat. The specimen made as the direction of manufacturer was stored at room temperature for about 7 days. The standard surface preparation was routinely carried out. The 0.9% saline solution was used as electrolyte in pH 6.8-7.0 at $37^{\circ}C$. The open circuit potential was determined after 30 minutes' immersion of specimen. The scan rate was 1mV/sec and the surface area of amalgam exposed to the solution was 0.785$cm^2$ for each specimen. All potentials reported are with respect to Ag/AgCl eelctrode. The following results were obtained. 1. The corrosion potential of high copper amalgams was higher than one of low copper amalgams, and the current density of high copper amalgam was lower than one of low copper amalgams. 2. The low copper amalgams had the similar pattern of polarization curve, but the high copper amalgams had the different pattern one another. 3. The polarization curve of Orosphere amalgam which is the admixed type was similar to one of low copper amalgam.