Finishing techniques for amalgam restorations: Clinical assessment at three years

Use of the optimum finishing technique for an amalgam restoration may enhance the marginal integrity of the restoration and discourage its unnecessary early replacement. Two hundred and twenty-eight high copper amalgam restorations in 56 patients were evaluated, using clinical assessment criteria, up to three years after placement. Each patient had received at least one carved-only amalgam, at least one immediately finished restoration, and at least one amalgam that was polished at a subsequent appointment. Regardless of the finishing technique, the restorations exhibited similar marginal integrity up to three years after placement. Polished restorations were found to have substantially superior surface texture and less likelihood of surface discoloration. No evidence was found to support the use of immediate finishing techniques. The clinical significance of these findings, with respect to the need to polish amalgam restorations, is discussed.     

Amalgam phase down: baseline data preceding implementation in Nigeria

Objective: The Minimata Convention on mercury includes amalgam phase-down and eventual phase-out from dentistry. To aid its subsequent evaluation it is important to have baseline data of amalgam use in a locality prior to implementing a phase-down. Methodology: Records of patients spanning 5 years from January 2011 to January 2016 were analysed to determine and the compare frequency of amalgam usage with other dental materials for carious teeth restorations in a Nigerian university teaching hospital. Classes of cavities restored and cadres of operators who employed the different materials were included. Institutional ethics committee approval was obtained prior to commencing the study. Results: 2,058 patients’ records were retrieved, 59% females and 41% males. Their ages ranged 19–80 years, mean 33.5 ± 12.7 years, young adults 20–39 years old were the majority (62.9%). Filling materials included 57.5% amalgam, 17.6% glass ionomer cement (GIC) and 24.9% resin composite. Class I restorations constituted 70.5% of amalgam restorations, while Class II restorations made up 29.4% and Class V restorations accounted for 0.1%. Undergraduate dental students placed most of the amalgam restorations (60.5%), and 78.9% of all their restorations were amalgam. Less experienced dentists used all materials equally; the more experienced dentists placed more composite resin and GIC (43.3%). Conclusion: Amalgam fillings constituted nearly 60% of the restorations of carious teeth. Training of dental students in placement of non-mercury alternatives to amalgam and Minimum Intervention Dentistry needs to be emphasized in dental schools. Phase-down of amalgam should be intensified in Nigeria with the ultimate aim of a phase-out in line with the Minamata Convention.Key words: Amalgam, phase-down, Nigeria, dental caries     

银粉玻璃离子和银汞合金用于治疗老年根面龋的疗效观察

目的观察银粉玻璃离子和银汞合金治疗老年患者后牙根面龋的临床疗效。方法将325颗根面龋坏后牙随机分为两组,分别采用银粉玻璃离子、银汞合金两种材料进行充填,随访观察2年。结果银粉玻璃离子填充组的成功率达91．41％,高于银汞合金填充组的7．28％,组间差异有统计学意义（P〈0.05）。结论银粉玻璃离子治疗老年后牙根面龋疗效较好。     

银汞充填对口腔科医生健康影响的调查

目的　研究使用银汞合金充填牙齿对口腔科医生健康的影响。方法　将 10 0位口腔科医生按用汞量分为两组 ,观察组 5 1名 ,为每月用汞量 80克以上的医生 ,对照组 4 9名 ,为每月用汞量 2 0克以下的医生 ,详细记载两组的工作环境、操作方法、防护和体检情况。结果　观察组医生出现牙龈炎、头晕、失眠、腰痛、记忆力减退、性格变急躁易怒 ,手指颤、唾液分泌增多、尿汞高等症状和体征与对照组间差异有显著性意义 (P <0 0 5 )。结论　长期大量使用手工调制的银汞合金 ,如不注意防护 ,口腔科医生易患慢性汞中毒。     

Replacement risk of amalgam treatment modalities: 15-year results

Objectives: This paper reports on the replacement risk of different treatment modalities for Class II amalgam restorations in a clinical trial of 15 years' duration.

Methods: The performance of 1117 conventional Class II amalgam restorations in a controlled, longitudinal study were analysed using logistic regression with a random component. Primary variables regarding replacement risk were the treatment modality (cavity wall treatments) and alloy (conventional versus high copper). Secondly, the operator, type of tooth and type of restoration (MO/DO vs MOD) were considered.

Results: Over 15 years, 17% of the restorations were replaced (true failures). The application of copalite varnish or silver suspension and the type of alloy did not reduce the replacement risk. Reduced risks were observed by providing a 90° cavosurface angle combined with a cavity wall finish. The operator and the type of restoration determine replacement risk to a significant extent.

Conclusions: Additional treatment modalities do not necessarily reduce replacement risks of Class II amalgam restorations within 15 years, while clinical variables affect the risk of replacement to a certain degree.     

Amalgam restorations, plaque removal and periodontal health

Abstract. A total of 156 approximal subgingival amalgam overhanging margins were assessed in the buccal segments of 13 patients for plaque accumulation, gingival inflammation, pocket depth and gingival shrinkage. Recordings were made immediately before and 2, 4 and 8 weeks fallowing scaling, removal of overhangs, and oral hygiene instruction. Surfaces with overhangs were compared with control surfaces, which were either intact or contained supragingival amalgams. Initially it was found that gingival inflammation and pocket depth were more extensive adjacent to subgingival amalgam overhangs than to sound teeth or those with supragingivally located amalgams. This appeared to be due to preferential plaque accumulation in relation to subgingival overhangs. For all parameters compared, differences apparent at the baseline had disappeared by the end of the 8-week study period. Contouring of defective subgingival restorations, followed by effective scaling and oral hygiene instruction produced approximately 1 mm of gingival shrinkage, sufficient in most cases to produce clinical gingival health. Of the 156 subgingival fillings 83 (53 % ) became supragingival and 43 (28 %) reached the gingival crest by the end of the 8-week study period.     

Evaluating amalgam separators using an international standard

BACKGROUND: Most amalgam particles generated during placement and removal of amalgam restorations are captured by chair-side traps and suction system traps and filters. Particles not captured can end up in the wastewater discharged from the dental office. Environmental initiatives to reduce the discharge of mercury-containing products such as dental amalgam waste into the environment have sparked interest in the use of amalgam separators. METHODS: The authors used International Organization for Standardization (ISO) Standard 11,143 for Amalgam Separators in a laboratory test to evaluate the amalgam removal efficiency of 13 commercially available amalgam separators and two commercially available filtration devices not marketed as amalgam separators but that have the potential to be used as such. RESULTS: All 13 amalgam separators and the two filtration devices exceeded the ISO Standard 11,143 requirement of 95 percent amalgam removal efficiency. The authors found statistical differences in the efficiency of the separators and filtration devices. No differences were found between the "empty" and "full" conditions for each separator. CONCLUSION AND CLINICAL IMPLICATIONS: This laboratory evaluation shows that amalgam separators and the filtration devices removed at least 97.05 percent of the amalgam in samples with particle-size distribution as specified in ISO Standard 11,143.     

Amalgam waste management

Dental amalgam has been extensively used as a tooth filling material for many decades and has beyond doubt saved millions of teeth that otherwise would have needed to be extracted. The release of amalgam particles into dental office wastewater is a matter of particular concern as amalgam particles could then be discharged into the environment. Amalgam waste discharges contribute to mercury in the environment through direct wastewater discharge, incineration, land-filling and sewage sludge incineration, although the discharge from dentistry is probably responsible for less than 1% of the total mercury discharged annually into the environment as a result of human activities. Nevertheless, dentists, by being producers of amalgam waste, have a responsibility and a duty of care for the proper management of this waste within their practices. Appropriate measures should be taken to minimise the amount of waste where possible or take action to ensure that all generated waste is disposed of in accordance with environmental legislation.     

INFLUENCE OF THERMAL STRESS ON MARGINAL INTEGRITY OF RESTORATIVE MATERIALS

The aim of this study was to evaluate the influence of thermal stress on the marginal integrity of restorative materials with different adhesive and thermal properties. Three hundred and sixty Class V cavities were prepared in buccal and lingual surfaces of 180 bovine incisors. Cervical and incisal walls were located in dentin and enamel, respectively. Specimens were restored with resin composite (RC); glass ionomer (GI) or amalgam (AM), and randomly assigned to 18 groups (n=20) according to the material, number of cycles (500 or 1,000 cycles) and dwell time (30 s or 60 s). Dry and wet specimens served as controls Specimens were immersed in 1% basic fuchsine solution (24 h), sectioned, and microleakage was evaluated under x40 magnification. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests: Thermal cycling regimens increased leakage in all AM restorations (p<0.05) and its effect on RC and GI restorations was only significant when a 60-s dwell time was used (p<0.05). Marginal integrity was more affected in AM restorations under thermal cycling stress, whereas RC and GI ionomer restoration margins were only significantly affected only under longer dwell times.     

Amalgamdepositionen in einem gastralen Leiomyosarkom Fallbeschreibung einer ungewöhnlichen Amalgamkonstellation

We report an a 57-year-old man with gastric leiomyosarcoma containing depositions of amalgam that possibly originate from a swallowed filling. The significance of this finding remains unclear. This case does not permit any conclusions as to whether this is a coincidence or not. The worldwide use of amalgam without an increase of oral sarcomas/leiomyosarcomas speaks against the supposition that amalgam induces sarcomas.