Defective Amalgam Research Articles

Association between dental amalgam restoration and urine mercury concentrations among young women in Korea: a cross-sectional study.

The association between dental amalgam fillings and urine mercury concentrations was investigated in this study to assess the health risks associated with dental amalgams. 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. The mean±standard deviation of the urine mercury concentrations of the exposure and nonexposure groups were 1.50±1.78 μg/g creatinine and 0.53±0.63 μg/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). According to this study, exposure to dental amalgams was confirmed to significantly affect urine mercury concentrations.

Fracture resistance of defective amalgam restorations repaired with a resin-based composite material

BackgroundRepair is used to increase the longevity of defective restorations, such as large amalgams. The aim of this study was to investigate the fracture resistance and fracture modes of mesio-occlusodistal (MOD) amalgam molar restorations with extensive cuspal fracture repaired or replaced using a bulk-fill resin-based composite material. MethodsAmalgam restorations were placed in 84 permanent extracted molars and randomly assigned (n = 14) to groups: (1) MOD amalgam, (2) composite repair of 1-cusp fracture and adjacent proximal box, (3) composite repair of 1-cusp fracture, (4) composite repair of 2-cusp fracture, (5) replacement of 1-cusp defect and existing MOD amalgam, (6) replacement of 2-cusp defect and MOD amalgam. Each molar was prepared to simulate the assigned fracture and either repaired or replaced. Specimens were aged and then loaded to fracture. Fracture resistance and fracture modes were recorded. ResultsThe authors found significant differences (P < .001) between group 4 (1,652.3 N) and groups 5 (3,095.0 N), 1 (2,669.8 N), 6 (2,658.6 N), and 2 (2,442.9 N) as well as between group 3 (2,133.5 N) and group 5 (3,095.0 N). The results of the Fisher exact test showed differences among groups (P < .001), with group 5 having the highest number of nonrestorable fractures as well as higher fracture resistance on average. ConclusionsComposite material is a viable option for the repair and replacement of cuspal defects, especially in the case of a 1-cusp fracture and 1-cusp fracture involving the adjacent proximal box. Practical ImplicationsWithin the limitations of this study, the repair of cusp fractures in existing MOD amalgam–restored molars is an appropriate treatment option, although replacement of the defect and existing restoration with resin-based composite will withstand higher forces.

Kap Survey on Management of Defective Amalgam Restorations Among Dental Practitioners In Chennai

Kap Survey on Management of Defective Amalgam Restorations Among Dental Practitioners In Chennai

The Post-Amalgam Era: Norwegian Dentists' Experiences with Composite Resins and Repair of Defective Amalgam Restorations.

Amalgam was banned as a dental restorative material in Norway in 2008 due to environmental considerations. An electronic questionnaire was sent to all dentists in the member register of the Norwegian Dental Association (NTF) one year later, to evaluate dentists’ satisfaction with alternative restorative materials and to explore dentists’ treatment choices of fractured amalgam restorations. Replies were obtained from 61.3%. Composite was the preferred restorative material among 99.1% of the dentists. Secondary caries was the most commonly reported cause of failure (72.7%), followed by restoration fractures (25.1%). Longevity of Class II restorations was estimated to be ≥10 years by 45.8% of the dentists, but 71.2% expected even better longevity if the restoration was made with amalgam. Repair using composite was suggested by 24.9% of the dentists in an amalgam restoration with a fractured cusp. Repair was more often proposed among young dentists (p < 0.01), employees in the Public Dental Service (PDS) (p < 0.01) and dentists working in counties with low dentist density (p = 0.03). There was a tendency towards choosing minimally invasive treatment among dentists who also avoided operative treatment of early approximal lesions (p < 0.01). Norwegian dentists showed positive attitudes towards composite as a restorative material. Most dentists chose minimally- or medium invasive approaches when restoring fractured amalgam restorations.

A study on the survival of primary molars with intact and with defective restorations.

Failed restorations in primary teeth are not always re-restored. Is re-restoration not required anymore? To compare survival rates of primary molars with intact and defective amalgam and ART restorations. A total of 649 restored primary molars, of which 162 were assessed with defective restorations for mechanical reasons, from a cluster-randomised controlled clinical trial, were followed up over a period of 3.5 years. Restored primary molars, extracted because of dental sepsis or toothache, were considered a failure. Primary molars with defective restorations were followed up from the time they were assessed defective. Data were analysed using PHREG model with frailty correction, Wald test, t-test, and jackknife procedure. The survival rate of primary molars with intact restorations (96.3%) was statistically significantly higher than that of primary molars with defective restorations (75.9%) over a 3-year period (P < 0.0001). Neither the effect of treatment protocol (amalgam or ART) (P = 0.05) nor the type of surface (single or multiple) (P = 0.73) was observed with respect to the survival rate of restored primary molars. Survival rates for primary molars with intact and defective amalgam and ART restorations were high. The 3-year survival rate of primary molars with intact restorations was significantly higher than that of primary molars with defective restorations.

Defective amalgam restorations--repair or replace?

The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, BIOSIS via Web of Knowledge, Web of Science and Opengrey databases were searched. In addition researchers and experts in the field were contacted to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication. Randomised controlled trials (including split-mouth studies), involving replacement and repair of amalgam restorations in adults with a defective molar restoration in permanent molar or premolar teeth were to be considered. Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis. The search strategy retrieved 201 potentially eligible studies after de-duplication. After examination of the titles and abstracts, full texts of the relevant studies were retrieved but none of these met the inclusion criteria of the review. There are no published randomised controlled trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, distress and anxiety, time and costs.

Replacement versus repair of defective restorations in adults: amalgam

Amalgam is a common filling material for posterior teeth, as with any restoration amalgams have a finite life-span. Traditionally replacement was the ideal approach to treat defective amalgam restorations, however, repair offers an alternative more conservative approach where restorations are only partially defective. Repairing a restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement. Repair of amalgam restorations is often more conservative of the tooth structure than replacement. To evaluate the effects of replacing (with amalgam) versus repair (with amalgam) in the management of defective amalgam dental restorations in permanent molar and premolar teeth. For the identification of studies relevant to this review we searched the Cochrane Oral Health Group's Trials Register (to 5 August 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 7); MEDLINE via OVID (1946 to 5 August 2013); EMBASE via OVID (1980 to 5 August 2013); BIOSIS via Web of Knowledge (1969 to 5 August 2013); Web of Science (1945 to 5 August 2013) and OpenGrey (to 5 August 2013). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases. Trials were selected if they met the following criteria: randomised controlled trial (including split-mouth studies), involving replacement and repair of amalgam restorations in adults with a defective restoration in a molar or premolar tooth/teeth. Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis. The search strategy retrieved 201 potentially eligible studies after de-duplication. After examination of the titles and abstracts, full texts of the relevant studies were retrieved but none of these met the inclusion criteria of the review. There are no published randomised controlled trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, distress and anxiety, time and costs.

Dentes Posteriores: Critérios Utilizados num Caso Clínico

At reporting of any clinical case, it always would be interesting to point out the many reasons that gave support to the chosen treatment options, during all the developed steps, as expose the reasons that were used as a base to the choice of the employed procedures. With this philosophical focus, it is here presented a clinical case, involving substitution of amalgam by composite resin, in two upper left tooth from the posterior region (24 and 25), realized in a male patient that was treated in the Pos-graduation Clinic, at Bauru Dental School - USP. In the two involved premolars, the defective amalgam was substituted by Filtek Supreme, a composite resin, after realization of a general clinical evaluation, followed by anamnesis and analysis of the respective initial radiographies. In the way, besides a detailed description of clinical case, it were pointed out the reasons that served as basis to the choices of different procedures, beginning with explanation of why composite was elected to substitute amalgam.

Alternative treatments to replacement of defective amalgam restorations: Results of a seven-year clinical study

The authors conducted a prospective cohort clinical study to investigate the effectiveness of alternative treatments to the replacement of defective amalgam restorations. Fifty patients aged 21 through 77 years (mean age, 56 years) with 113 defective amalgam restorations that were diagnosed during treatment planning participated in the study. The authors assigned each tooth to one of five treatment groups: repair with amalgam (n = 20), sealing of defective margins (n = 23), refinishing (n = 23), replacement (n = 22) or no treatment (n = 25). The replacement and no-treatment groups served as comparison groups, and the authors assigned 47 teeth randomly to these groups. Two clinicians examined the restorations before and after the assigned treatment and at subsequent recall visits by using modified U.S. Public Health Service criteria including marginal adaptation, anatomic form, occlusal and proximal contact, postoperative sensitivity and secondary caries. The clinicians examined 94 restorations (83 percent) at the one-year recall visit, 74 (65 percent) at the two-year recall visit and 54 (48 percent) at the seven-year recall visit. They observed most of the downgraded and failed restorations after the first two years of clinical service. The study results show that some degree of degradation occurred in all treatment groups, including the replacement group, at the seven-year recall examination, with no significant failure rate. The results support the repair of defective amalgam restorations as an alternative to replacement. Furthermore, the study findings show that in future controlled clinical trials, all teeth may receive random assignment. The study findings support repair rather than replacement of amalgam restorations with localized defects. Randomized controlled trials are needed to confirm these findings.

Survival rate of sealed, refurbished and repaired defective restorations: 4-year follow-up

The most common treatment in general dental practice is the replacement of restorations affected by secondary caries or marginal deficiencies. Alternative treatments to replacement of defective restorations, such as marginal sealing, refurbishment and repair, have demonstrated improvement of their clinical properties with minimal intervention. The aim of this clinical study was to estimate the median survival time (MST) of marginal sealing, repair and refurbishment of amalgam and resin-based composite restorations with localized defects as a treatment to increase the restoration longevity. A cohort of 66 patients, with 271 class I and II restorations clinically diagnosed with localized defects was longitudinally assessed. Each restoration was assigned to one of the following 5 groups: Marginal Sealing (n=48), Refurbishment (n=73), Repair (n=27), Replacement (n=42), and Untreated (n=81). Two calibrated examiners assessed the restorations at baseline and annually during 4 years, using the modified Ryge criteria: marginal adaptation, anatomic form, roughness, secondary caries and luster. Fifty-two patients with 208 restorations were assessed after 4 years; the distribution of restorations in the groups was as follows: Marginal Sealing (n=36), Refurbishment (n=63), Repair (n=21), Replacement (n=28) and Untreated (n=60). Kaplan Meier test indicated that the Sealed margins group showed the lowest MST while the Repair group showed the highest MST for restorations examined after 4 years of follow up. Defective amalgam and resin-based composite restorations treated by sealing of marginal gaps, refurbishment of anatomic form, luster or roughness, and repair of secondary caries lesions, had their longevity increased.

Repair of amalgam restorations with composite resin and bonded amalgam: A microleakage study

Total replacement is the most common technique for defective amalgam restorations, and it represents a major part of restorative dental treatment. Repair is an alternative option for amalgam restorations with localized defects. This study compared microleakage of amalgam restorations repaired by bonded amalgam or composite resin. Thirty extracted human pre-molars were prepared and restored with class I amalgam. A simulated defect was prepared that included the cavosurface margin on restorations, and the pre-molars were assigned to two treatment groups (n=15): In group 1, premolars were treated by composite resin (34% Tooth Conditioner Gel + Adper Single Bond 2 + Z100) and in group 2, premolars were repaired by bonded amalgam (34% Tooth Conditioner Gel + Prime and Bond 2.1 + Permite C). The teeth were immersed in a 50% silver nitrate solution, thermocycled, sectioned longitudinally and then observed by three examiners using a stereomicroscope. Microleakage was evaluated using a 0-4 scale for dye penetration, and data was analyzed by Kruskal Wallis and Dunn tests. Neither of the two methods eliminated microleakage completely. Composite resin was significantly the most effective for repair/tooth interface sealing (score 0 = 80.0%; P=0.0317). For the repair/restoration interface, composite resin was also statistically more effective as a sealant (score 0=66%; P=0.0005) when compared to the bonded amalgam technique (score 0=13%; P=0.0005). The use of adhesive systems significantly affected the ability to seal the repair/ tooth interface. However, at the level of the repair/restoration interface, the bonded amalgam technique may increase microleakage.

Amalgam Repair: Quantitative Evaluation of Amalgam-resin and Resin-tooth Interfaces with Different Surface Treatments

The successful addition of new restorative materials to an existing restoration may be the most conservative course of treatment. Repairing amalgam restorations with resin materials remains a viable clinical alternative to amalgam replacement. This in vitro study evaluated the effect of different adhesive systems and surface treatments on the integrity of amalgam-resin and resin-tooth interface after partial removal of pre-existing amalgam. Fifty defect-free human molars were restored with amalgam occlusally. The teeth were thermocycled (1,000x) between 5 degrees C and 55 degrees C, with a dwell time of 30 seconds. The mesial and distal parts of the amalgam fillings were removed, leaving only the middle part of amalgam. One side of the cavity was finished with a coarse diamond bur, while the other part of the amalgam was finished with a fine diamond bur. The samples were then randomly divided into five groups (n = 10/group) and received the following adhesive systems: Group 1: All Bond 3 (BISCO, Inc); Group 2: Clearfil SE Bond+Alloy Primer (Kuraray); Group 3: Kuraray DC Bond (Kuraray); Group 4: Xeno V (Dentsply); Group 5: XP Bond (Dentsply). All the cavities were restored with resin composite (TPH Spectrum, Dentsply). All the materials were used according to the manufacturer's directions. The specimens were re-thermocycled (1,000x), sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned mesiodistally and photographed digitally. The extent of dye penetration on the tooth-sealant interface was measured by image analysis software (ImageJ, Scion Image, Frederick, Maryland, USA) for both coarse-finished and fine-finished surfaces at the resin-tooth and resin-amalgam interface. The data were analyzed statistically with one-way ANOVA and post hoc Tukey tests (alpha = 0.05). All Bond 3 and XP bond (etch & rinse) produced the best results at each section. All the materials exhibited more microleakage at the amalgam interface than the tooth interface. Surface finishing with different burs did not statistically affect microleakage. In terms of microleakage reduction, etch & rinse adhesives may be preferred over self-etch adhesives for amalgam repair.

Evaluation of the dental structure loss produced during maintenance and replacement of occlusal amalgam restorations

The aim of this in vitro study was to evaluate four different approaches to the decision of changing or not defective amalgam restorations in first primary molar teeth concerning the loss of dental structure. Ditched amalgam restorations (n = 11) were submitted to four different treatments, as follows: Control group - polishing and finishing of the restorations were carried out; Amalgam group - the ditched amalgam restorations were replaced by new amalgam restorations; Composite resin group - the initial amalgam restorations were replaced by composite resin restorations; Flowable resin group - the ditching around the amalgam restorations was filled with flowable resin. Images of the sectioned teeth were made and the area of the cavities before and after the procedures was determined by image analysis software to assess structural loss. The data were submitted to ANOVA complemented by the Student Newman Keuls test (p < 0.05). The cavities in all the groups presented significantly greater areas after the procedures. However, the amalgam group showed more substantial dental loss. The other three groups presented no statistically significant difference in dental structure loss after the re-treatments. Thus, replacing ditched amalgam restorations by other similar restorations resulted in a significant dental structure loss while maintaining them or replacing them by resin restorations did not result in significant loss.

2-year Clinical Evaluation of Alternative Treatments to Replacement of Defective Amalgam Restorations

To investigate the effectiveness of alternative treatments for replacing defective amalgam restorations through a prospective longitudinal cohort clinical study. Forty-five patients aged 21 through 77 (mean=56) years with 113 defective amalgam restorations, which were independently diagnosed during treatment planning, participated in the study. These patients were assigned to 5 treatment groups: repair (n=20), sealing of defective margins (n=23), refurbishing (n=23), replacement (n=23) and no-treatment (n=24). The replacement and no-treatment groups served as comparison groups and received random assignment. Two clinicians examined the restorations (n=113) prior to and after the assigned treatment and at subsequent recalls, using a modified Ryge Criteria that included marginal adaptation, anatomy, contact, post-operative sensitivity and secondary caries. At 1- and 2-year recalls, 79 (70%) and 74 (65%) restorations were examined. Kruskal-Wallis Test showed significant differences for marginal adaptation and anatomic form for both 1- and 2- year recall exams (p<.05). The repair and replacement groups had significant differences when compared to the no-treatment group. Defective restorations that have a Bravo rating for clinical characteristics other than marginal integrity and anatomical form do not need to be immediately replaced.

Mercury concentrations in urine, scalp hair, and saliva in children from Germany.

Mercury levels measured in urine, hair, and saliva of 245 German children (8-10 years old) are reported. Mercury concentrations in urine ranged between <0.1 and 5.3 microg/l [geometric mean (GM) 0.26 microg/l or 0.25 microg/g creatinine; median for both, 0.22 in microg/l and microg/g, respectively]. Using multiple linear regression analysis, two predictors have been found accounting for 25.3% of the variance of mercury levels in urine: the number of teeth with amalgam fillings (23.2%) and the number of defective amalgam fillings (2.1%). The mercury content in hair ranged from <0.06 to 1.7 microg/g (GM 0.18 microg/g; median 0.18 microg/g). The frequency of fish consumption, the smoking habits of the parents, and the age of the children accounted for 20.4% of the variance of mercury levels in hair. The correlation between the hair mercury content and urine mercury concentration was low (r=0.297). Mercury levels in saliva ranged between <0.32 and 4.5 microg/l (median 0.16 microg/l). The mercury concentration in saliva was below the limit of quantification of 0.32 microg/l in more than 70% of the samples. Mercury analysis in urine is suitable to estimate mercury exposure due to amalgam fillings, whereas hair mercury better reflects mercury intake by fish consumption. Up to now, saliva does not seem to be a suitable tool to monitor the mercury burden, at least not at low exposure levels.

Validity of clinical judgements for the presence of secondary caries associated with defective amalgam restorations.

Eighty patients were selected, who were each deemed to require the replacement of a defective amalgam restoration. The patients had a mean age of 36.7 years and were dentally fit on average 40 months previously. The main reasons given for the replacement of the defective restorations were perceived radiographic secondary caries (31%), fracture of the restoration (20%), marginal defect (17%), and perceived secondary caries observed clinically (14%). Following the removal of the restorations, a highly significant relationship was found between the consistency and colour of the underlying dentine (P < 0.00001). Soft dentine was found underlying 36 (88%) of the 41 defective amalgam restorations which were diagnosed as having caries associated with them. However, hard dentine was found underlying only 19 (49%) of the 39 teeth where no caries had been diagnosed. The presence of soft dentine where not anticipated was mainly in association with fractured restorations (11 out of 16). Younger patients were more likely to have soft dentine underlying their defective amalgam restorations than older patients (P = 0.005). No relationship was found between the presence of corrosion products on the cavity walls associated with defects and the consistency of the underlying dentine.

Amalgam repair—A clinical technique

T he repair of a defective amalgam restoration, abutting a new amalgam restoration against an existing one, is practiced in the operatory without a definitive technique. It is the purpose of this article to consider the clinical implications of this procedure and to present a simple and effective technique for repairing or abutting fresh amalgam to an existing amalgam restoration. Terkla et al.’ reported on the bond strength of repaired amalgam using a transverse bend test and found it to be less than 50% of the unrepaired controls. They also reported that specimens repaired after being stored for 7 days possessed approximately half the bond strength of specimens repaired after 15 minutes. Jorgensen and Saito* also observed less than 50% bond strength under similar conditions; however, when they pretreated the specimens with one drop of mercury forcibly rubbed into the surface to be bonded, they reported strengths of 90% and 97% of their controls. They also found that the fracture sites of the pretreated specimens most frequently occurred outside the junction between old and new amalgam and that whenever the fracture did include the junction area, clear signs of union were seen. Consani et al.’ and Kirk,4 in independent studies, investigated the nature of the bond and its tensile strength. Both reported evidence of metallurgical bonding, but Consani et al. referred to it as “imperfect” since varying degrees of dye penetration were observed. The Consani group reported tensile strengths of the bond to be approximately one third of their controls. Kirk found bond strengths ranging from 23% to 98%, while approximately one third of his bonded specimens had tensile strengths almost equal to the controls. All investigations reported in the literature concerning this subject have been in vitro studies. When new