From amalgam to composite: selection of restorative materials and restoration longevity in Finland

The aim of this study was to obtain information on restorative dental care in Finland and to analyze the changes in treatment over a 5-year period. A random sample of dentists was drawn from the registers of the health authorities and the dental association in Finland, and in the spring of 1997 a questionnaire was sent requesting the dentists to record information for each restoration placed during a given period. A total of 1,229 dentists were contacted, and 659 responded. The dentists treated 5,305 adults during the study period and placed 6,322 restorations. The most common restorative material was composite resin, which was used in 74.9% of the restorations, whereas amalgam was used in 4.8% and glass ionomers in 9.4% of the restorations. The median ages of failed restorations were nearly 12 years for amalgam, slightly less than 5 years for composite, and slightly more than 4 years for glass ionomer. The results indicate that clinical dentistry in Finland has made a definite step towards the post-amalgam era. However, the functional periods of the failed tooth-colored restorations were disappointingly short and warrant some serious consideration.     

Long-term deterioration of composite resin and amalgam restorations.

Previous long-term longitudinal studies of two different methods of placing an auto-cured conventional anterior composite resin, and of a low- and a high-copper amalgam alloy, had shown similar restoration survivals despite the different resin treatment methods used or the types of amalgam alloy placed. Therefore, the aim of the present study was to assess several clinical factors or characteristics of these restorations that were believed to affect the survival of the restorative materials. The 950 composite resin and the 1042 amalgam restorations examined were placed by many operators in numerous patients attending a dental hospital. The composite resin restorations were placed using unetched- and etched-enamel-bonding treatment methods, and the amalgam restorations were polished after insertion. Clinical ratings supplemented by color transparencies were used for the assessment of four factors for the resin, and four factors for the amalgam restoration. Significant deterioration differences were found for several of the clinical factors assessed for both the two different composite resin treatment methods, and for the two different amalgam alloys, which were not directly related to the restoration survivals.     

Amalgam and composite posterior restorations: curriculum versus practice in operative dentistry at a US dental school

This study recorded the number of preclinical lecture and simulation laboratory sessions spent teaching the preparation and placement of amalgam and resin composite posterior restorations. These data were compared to the use of both materials in the operative clinic as placed by third- and fourth-year students. The number of posterior restorations inserted by the students, expressed as a function of the number of restoration surfaces, was also evaluated. The results show that the teaching of posterior restorations pre-clinically has consistently favored amalgam 2.5 to 1 during the last three years. However, clinically, resin composite is being used for posterior restorations 2.3 times more often than amalgam. The only instance that favored amalgam over composite during the last year was in the placement of four surface posterior restorations. This shift in emphasis from amalgam to composite needs to be addressed within dental educational institutions so that newly graduated dentists are prepared to place composite restorations properly.     

Direct placement restorative materials for use in posterior teeth: the current options

The purpose of this paper is to provide guidelines to assist in the selection of dental materials for restoring posterior teeth in adolescents. Currently, amalgam is still the best plastic restorative material for some Class I cavities, and for Class II cavities and all multi-surface restorations. Tooth-coloured materials are preferred by some patients and dentists, however these alternatives are more technique sensitive than amalgam. Composite resin is the most common direct placement alternative to dental amalgam, providing patients with relatively low cost, tooth-coloured restorations. However, composite resins have limited indication, their placement is more time-consuming than for amalgam, cost-benefit considerations are a concern, difficulty in obtaining a marginal seal persists and there are few long-term studies published in the peer reviewed scientific literature. The literature currently supports the use of composite resin for the restoration of a limited range of Class I and Class II cavities. Composite resin restorations are not recommended for MOD or other multi-surface restorations. In selected clinical situations, fissure sealants, preventive resin restorations and glass ionomer cement are also appropriate materials to use to restore posterior teeth. Fissure sealants, when properly maintained, can play a significant role in the prevention and control of dental caries in pits and fissures in primary and permanent teeth. Preventive resin restorations should be placed to restore deep pits and fissures with incipient caries and/or developmental defects in primary and permanent teeth. Glass ionomer cement may be used for restoring Class V cavities where appearance is not the primary concern, for conservative Class III cavities, and as a provisional restorative material. It is not recommended for Class II or IV restorations.     

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     

Early failure of Class II resin composite versus Class II amalgam restorations placed by dental students

Using the information from remake request slips in a dental school's predoctoral clinic, we examined the short-term survival of Class II resin composite restorations versus Class II dental amalgam restorations. In the student clinic, resin composite is used in approximately 58 percent of Class II restorations placed, and dental amalgam is used in the remaining 42 percent. In the period examined, Class II resin composite restorations were ten times more likely to be replaced at no cost to the patient than Class II dental amalgam restorations. A total of eighty-four resin composite restorations and six amalgam restorations were replaced due to an identified failure.     

Cariostatic and ultraconservative sealed restorations: six-year results.

The objective of this clinical study was to determine the ability of an ultraconservative, sealed composite resin restoration, without a traditional cavity preparation and without the removal of the carious lesion, to arrest Class I caries. Tooth preparation was limited to placing a bevel in the enamel. These restorations were compared, over 6 years, with (1) ultraconservative, localized, sealed amalgam restorations with no extension for prevention and (2) traditional, unsealed amalgam restorations with the usual extension for prevention outline form. Caries was arrested by the ultraconservative, sealed composite resin restorations for 6 years. Complete sealant retention on the sealed amalgam restorations was somewhat lower than that on the sealed composite resin restorations; conversely, partial sealant retention was higher for the sealed amalgam group. The marginal integrity of the sealed amalgam restorations was significantly superior to that of the unsealed amalgam restorations. The sealant also protected Class I posterior composite resin restorations against wear.     

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复合树脂材料用于牙科已有20余年历史。这类材料既可用于前牙也可用于后牙。复合树脂发展到今天已经出现了许多专门应用于后牙的修复材料,并已取得满意的临床效果。银汞合金的许多缺点都可以为复合树脂所克服。因此,后牙复合树脂修复已为越来越多的患者和牙科医生所接受。然而,直接充填复合树脂材料仍旧被认为有许多局限性。比如边缘缺陷、面磨损、牙尖变形以及术后的牙髓敏感等。因此,近年来发展了复合树脂的一种新技术——间接性复合树脂嵌体与高嵌体修复技术。它的临床应用在某种程度上克服了上述直接充填树脂的局限性。复合树脂嵌体或高嵌体是作为固体黏固在预备洞型中的一种修复体。这种呈固态的修复体由复合树脂材料采用间接的方法制成,最后再黏固于口内。本文将最近的有关间接性复合树脂嵌体和高嵌体方面的资料进行综述,包括它的临床应用,优缺点以及面临的问题等。     

The amalgam-free dental school

OBJECTIVES: To review the change in teaching of Restorative Dentistry at Nijmegen dental school over the period 1986 to the present. KEY POINTS: In 1986, class I and II resin composite restorations were included in the pre-clinical program. However, these courses still started with class I and II amalgam restorations. From 1990 on, the number of amalgam restorations placed in the clinic gradually decreased while the number of resin composite restorations increased. Meanwhile, resin composite had become the first choice for treatment of primary caries (class I and class II) lesions. Finally in 1994, the pre-clinical training started with resin composite restorations before dental amalgam was taught and the advantage of a minimal preparation was further emphasized. Since 2001 the teaching of dental amalgam ceased at the dental school. This was not an abrupt change but the result of a long transitional stage during which it was gradually substituted by resin composite. This step-by-step introduction allowed the acceptance of composite resin by the staff as an alternative for dental amalgam in posterior restorations. As in 2001 students placed only 2.5 amalgam restorations before graduation, it was decided to stop with the pre-clinical training program. CONCLUSIONS: The introduction of resin composites meant an important change in teaching restorative dentistry at Nijmegen dental school. It was not just a change in materials and techniques but also a change in treatment philosophy. The reduced need for preparation and the strengthening effect on the remaining tooth were the principal reasons for the shift from dental amalgam to adhesive dentistry with resin composite at Nijmegen dental school.     

Amalgam--Resurrection and redemption. Part 1: the clinical and legal mythology of anti-amalgam.

Dental amalgam has come under attack for its allegedly poor physical properties and clinical performance in addition to its poor appearance. It has been claimed that the American Dental Association has a hidden agenda to protect amalgam and that other countries have banned its use. A literature search revealed that the vast majority of amalgam restorations do not cause fractured cusps or have recurrent caries. Most amalgam restorations have been shown to last longer than resin composite restorations. In addition, the materials and techniques involved in amalgam restorations have vastly improved in recent years. Like resin composite restorations, amalgam restorations can often be repaired. The American Dental Association has no vested interest in protecting amalgam. The use of amalgam has not been banned in any country in the European Union. According to the latest scientific information available, dental amalgam is a remarkably durable and long-lasting restorative material. Although its appearance is unesthetic, its clinical performance and effectiveness are unsurpassed by those of resin composite.     

Survival and reasons for failure of amalgam versus composite posterior restorations placed in a randomized clinical trial

BACKGROUND: Failure of dental restorations is a major concern in dental practice. Replacement of failed restorations constitutes the majority of operative work. Clinicians should be aware of the longevity of, and likely reasons for the failure of, direct posterior restorations. In a long-term, randomized clinical trial, the authors compared the longevity of amalgam and composite. SUBJECTS, METHODS AND MATERIALS: The authors randomly assigned one-half of the 472 subjects, whose age ranged from 8 through 12 years, to receive amalgam restorations in posterior teeth and the other one-half to receive resin-based composite restorations. Study dentists saw subjects annually to conduct follow-up oral examinations and take bitewing radiographs. Restorations needing replacement were failures. The dentists recorded differential reasons for restoration failure. RESULTS: Subjects received a total of 1,748 restorations at baseline, which the authors followed for up to seven years. Overall, 10.1 percent of the baseline restorations failed. The survival rate of the amalgam restorations was 94.4 percent; that of composite restorations was 85.5 percent. Annual failure rates ranged from 0.16 to 2.83 percent for amalgam restorations and from 0.94 to 9.43 percent for composite restorations. Secondary caries was the main reason for failure in both materials. Risk of secondary caries was 3.5 times greater in the composite group. CONCLUSION: Amalgam restorations performed better than did composite restorations. The difference in performance was accentuated in large restorations and in those with more than three surfaces involved. CLINICAL IMPLICATIONS: Use of amalgam appears to be preferable to use of composites in multisurface restorations of large posterior teeth if longevity is the primary criterion in material selection.     

Restorative service patterns in Australia: amalgam, composite resin and glass ionomer restorations

AIM: To examine the provision of amalgam, composite resin and glass ionomer restorations, and to assess whether these main restorative services varied by patient, visit and oral health characteristics. DESIGN: A cross-sectional survey incorporating a log of service items provided on a typical day. SETTING: Australian private general practice. METHODS: Data on services and patients were collected by a mailed survey from a random sample of dentists from each State/Territory in Australia in 1998-99 with a response rate of 71%. MAIN OUTCOME MEASURES: Rates per visit of amalgam, composite resin and glass ionomer restorations among dentate adults who had received a restoration. RESULTS: Analysis showed older patients had lower amalgam rates but higher glass ionomer rates, composite resin rates were lower at emergency visits, capital city patients had higher amalgam rates but lower composite resin rates, patients with decayed teeth had higher amalgam and composite resin rates, and use of restorative materials varied by clinical problem. CONCLUSIONS: Despite widespread use of alternative materials, amalgam rates remained high in circumstances such as replacement restorations and restorations involving more than one surface. Other restorative materials also had specific applications. Both amalgam and composite resins were provided at higher rates to patients with active caries but composite resins were also used at higher rates for aesthetic problems. Glass ionomer restorations were used at higher rates for initial and one-surface restorations, and for conditions such as root caries and dentinal sensitivity.     

A clinical evaluation of posterior composite resin restorations

There is a trend towards manufacturers seeking to provide dentists with a single, all-purpose composite resin, usually of the small particle hybrid type. This three-year clinical study compared the clinical performance of three different types of composite resin used in posterior teeth and identified several modes of failure. Of the 330 restorations (three composite resins and one amalgam control) initially placed in 72 patients, 223 restorations in 48 patients were available for evaluation at three years. Modified clinical criteria for assessing the restorations were able to discriminate among the composite resins. A microfilled composite and a small particle hybrid exhibited increasing evidence of marginal fracture (crevice) with time. In addition, the small particle hybrid showed evidence of wear at the margins more frequently than the other materials. Of the restorations available for assessment, four restorations of each of these two types of composite resin required replacement during the study. Coarse particle hybrid restorations showed evidence of wear but little evidence of marginal fracture.     

Attitudes and use of rubber dam by Irish general dental practitioners

AIM: To investigate the attitudes towards and use of rubber dam by Irish general dental practitioners. METHODOLOGY: A pre-piloted questionnaire was distributed amongst a group of 600 dentists randomly selected from the Irish Register of Dentists. Replies from dentists working in specialist practice or the hospital dental service were excluded. Dentists were surveyed in relation to their use of rubber dam during a variety of operative and root canal treatments, as well as their attitudes to the use of rubber dam in dental practice. RESULTS: A total of 300 replies were considered from a total of 324 that were received. Seventy-seven per cent of respondents (n=231) worked in general dental practice and 23% (n=69) worked in the Irish Health Board/Community Dental Service. Rubber dam was 'never' used by 77% of respondents (n=228) when placing amalgam restorations in posterior teeth, 52% (n=147) when placing composite restorations in posterior teeth, and 59% (n=177) when placing composite restorations in anterior teeth. Rubber dam was 'never' used by 39% of respondents (n=114) when performing root canal treatment on anterior teeth; 32% (n = 84) when performing root canal treatment on premolar teeth; and 26% (n=51) when performing root canal treatment on molar teeth. Fifty-seven per cent (n=171) considered rubber dam 'cumbersome and difficult to apply', and 41% (n=123) considered throat pack 'as good a prevention against inhalation of endodontic instruments as rubber dam'. CONCLUSIONS: Whilst rubber dam is used more frequently for root canal treatment than operative treatment, its use is limited. This presents quality issues, as well as medico-legal and safety concerns for both the profession and patients.     

Amalgam or composite in pediatric dentistry: Analysis of private insurance claims data

BackgroundAdvancements in dental materials and changing parental preferences are modifying the frequency of use of restorative materials. This insurance claims analysis examined the trends in the use of amalgam and resin composite in the United States.MethodsCommercial dental insurance claims were analyzed to compare 505,994 restorations, corresponding with procedure codes for 1-, 2-, and 3-surface amalgam or resin restorations. Paid claims collected nationwide from January 2010 through March 2020 were analyzed. Data for children aged 3 through 12 years were used, resulting in 219,632 unique patient identification numbers. Generalized estimating equation models applied to logistic regression were used. All tests were conducted using a 2-sided 5% significance level.ResultsIn general, girls were less likely to receive amalgam than boys. A $20,000 increase in median household income was associated with a 16% decrease in the odds of amalgam being placed. Pediatric dentists (performing 15.1% of all restorations) were not as likely as general dentists (18.4%) to use amalgam. Having more surfaces in a restoration was associated with higher probability of amalgam placement. The percentage of amalgam restorations was higher for 2010 (26.9%) than for 2011 through 2020, and this pattern recurred in several of the years analyzed. Generally, patient age at time of amalgam restoration increased over time.ConclusionThe use of amalgam is trending down; the sharpest decline was noted in 2014. Pediatric dentists were less likely to use amalgam than general dentists. Girls and patients with higher socioeconomic status were less likely to have amalgam.Practical ImplicationsThe findings of this study can inform and support clinical decisions and the formation of public policies.     

Reasons for Placement of Restorations on Previously Unrestored Tooth Surfaces by Dentists in The Dental Practice-Based Research Network

ObjectiveThe authors conducted a study to identify and quantify the reasons used by dentists in The Dental Practice-Based Research Network (DPBRN) for placing restorations on unrestored permanent tooth surfaces and the dental materials they used in doing so.MethodsA total of 229 DPBRN practitioner-investigators provided data from their practices regarding 9,890 consecutive restorations in 5,810 patients. Information the practitioner-investigators provided included their reasons for restoring the teeth, the specific teeth and surfaces they restored and the restorative materials they used.ResultsPrimary caries (85 percent of teeth, 8,351 of 9,890) and noncarious defects (15 percent, 1,479 of 9,890) were the main reasons participants gave for placing restorations. Participants placed restorations necessitated by caries most frequently on occlusal surfaces (49 percent, 4,091 of 8,351). They used amalgam for 47 percent of the molar restorations and 45 percent of the premolar restorations. They used directly placed resin-based composite (RBC) for 48 percent of the molar restorations, 50 percent of the premolar restorations and 93 percent of the anterior restorations.ConclusionDPBRN practitioner-investigators cited dental caries on occlusal and proximal surfaces of molar teeth as the main reasons for placing restorations on previously unrestored tooth surfaces. RBC was the material they used most commonly for occlusal and anterior restorations. Amalgam remains the material of choice to restore posterior teeth with proximal caries, although the authors noted significant differences in the use of amalgam and RBC by dentists in various regions of the DPBRN.     

Reasons for restorative therapy and the longevity of restorations in adults

The aim of this study was to obtain information on the restorative dental care of adults in Finland. A random sample of private dentists was drawn from the register, and in spring 2000 they were sent a questionnaire requesting them to record information for each restoration placed during one ordinary working day. A total of 800 dentists were contacted and 548 responded. The dentists reported placement of 3,455 restorations. Of these, 5% were Class I, 36% were Class II, 13% were Class III, 9% were Class IV, 21% were Class V, and 16% were extensive restorations including 4 or more surfaces. Overall, composite resin was the most common restorative material, and it was used in 79% of the restorations, whereas amalgam was used in 5%, compomers in 4%, and glass ionomers (either conventional or resin‐modified) in 7% of cases. In 5% of the cases, the tooth was restored with indirect restorative methods, using either gold or ceramic materials. Of the treatments, 65% were replacements of previous restorations. Secondary caries was the most common reason for replacement (36%, 52%, and 41% for composite, glass ionomer, and amalgam, respectively). Other common reasons were fractures of the tooth or restoration (23%, 11%, and 22% for composite, glass ionomer, and amalgam, respectively) and lost composite restorations (16%). The median age of failed restorations was 15 years for amalgam, 6 years for composite, and 7 years for conventional glass ionomer. Although the longevity of tooth coloured restorations was shorter than that of amalgam, comparisons with our previous studies indicate improved survival periods for tooth coloured materials.     

Impact of dental restorations and removable prostheses on potentially malignant oral mucosal disorders in the general population

Statement of problemDental restorations and removable dental prostheses have been considered as risk factors for potentially malignant disorders of the oral mucosa. It remains unclear whether amalgam, composite resins, and prosthesis materials can induce potentially malignant disorders.PurposeThe purpose of this clinical study was to determine the relationship between the presence of amalgam and composite resin restorations, crowns and fixed partial dentures, and removable prostheses in potentially malignant disorders.Material and methodsThe data of 6041 participants in the population-based Studies of Health in Pomerania (SHIP) were accessed. Potentially malignant disorders had been clinically diagnosed by calibrated dentists and documented with photographs. Dental treatment was subdivided into restored and replaced teeth. Dental restorations were subclassified as buccal composite resin or amalgam restorations. Prosthetic treatment was subclassified into removable partial or complete prostheses and definitive restorations with crowns and fixed partial dentures.ResultsIn the maxilla, participants with removable prostheses had a higher incidence of potentially malignant disorders than participants not undergoing treatment with removable prostheses (OR 2.12; 95% CI: 1.08-4.18), but not in the mandible (OR 1.30; 95% CI: 0.67-2.53). The surfaces with composite resin restorations were associated with a slightly higher risk of mucosal lesions than those without the restorations (OR 1.04; 95% CI: 1.01-1.07). No significant association was found between amalgam restorations and mucosal lesions.ConclusionsParticipants with removable prostheses have a higher risk of potentially malignant disorders. Composite resin restorations are associated with a higher risk of mucosal lesions, whereas no significant association was found between amalgam restorations and mucosal lesions.     

Reasons for restorative therapy and the longevity of restorations in adults

The aim of this study was to obtain information on the restorative dental care of adults in Finland. A random sample of private dentists was drawn from the register, and in spring 2000 they were sent a questionnaire requesting them to record information for each restoration placed during one ordinary working day. A total of 800 dentists were contacted and 548 responded. The dentists reported placement of 3,455 restorations. Of these, 5% were Class I, 36% were Class II, 13% were Class III, 9% were Class IV, 21% were Class V, and 16% were extensive restorations including 4 or more surfaces. Overall, composite resin was the most common restorative material, and it was used in 79% of the restorations, whereas amalgam was used in 50%, compomers in 4%, and glass ionomers (either conventional or resin-modified) in 7% of cases. In 5%, of the cases, the tooth was restored with indirect restorative methods, using either gold or ceramic materials. Of the treatments, 65% were replacements of previous restorations. Secondary caries was the most common reason for replacement (36%, 52%, and 41% for composite, glass ionomer, and amalgam, respectively). Other common reasons were fractures of the tooth or restoration (23%, 11%, and 22% for composite, glass ionomer, and amalgam, respectively) and lost composite restorations (16%). The median age of failed restorations was 15 years for amalgam, 6 years for composite, and 7 years for conventional glass ionomer. Although the longevity of tooth coloured restorations was shorter than that of amalgam, comparisons with our previous studies indicate improved survival periods for tooth coloured materials.     

Observations in Australia of the use of glass ionomer cement restorative material

The aim of this study was to evaluate, with the aid of a questionnaire distributed to selected groups of dentists, the use of glass ionomer cement in different types of proximal restorations and further to evaluate any complications observed with the use of GIC. Few dentists responded in the 'Often' category regarding the observation of secondary caries or gingival inflammation in association with GIC fillings compared with about three-quarters of the dentists who reported on posterior composite resin restorations. Tunnel cavities had been prepared and restored by 54 per cent of the dentists, simple proximal restorations in primary molars by 89 per cent and 'sandwich' restorations by 69 per cent. Few dentists with at least two years experience with tunnel restorations observed biological complications, but fracture of the marginal ridge was reported in the 'Often' category by 12 per cent. Among the dentists with at least five years experience with proximal restorations in primary molars 59 per cent of the operators mentioned more complications with these than with amalgam restorations. Biological complications were not a great problem with glass ionomer/composite laminates but wear or dissolution of the proximal GIC surface was recorded in the 'Often' section by 14 per cent of those placing them.