Trends in material choice for posterior restorations in an Israeli dental school: composite resin versus amalgam

According to a recent American Dental Association survey, posterior composite resin restorations now outnumber amalgam restorations in the United States. Dental schools around the world vary considerably in the extent to which they teach the use of composite resins. We aimed to determine if there has been an increase in the placement of posterior composite restorations in an Israeli dental school and if faculty experience affects the type of posterior restoration placed. In this retrospective study, we recorded and analyzed all the restorations performed by undergraduate students in the last five academic years at the Hebrew University Hadassah School of Dental Medicine in Jerusalem. All clinical records of student treatments between 2004 and 2009 were screened, and direct restorations were registered. Out of 6,094 posterior restorations performed during the study period, 42.3 percent were made of composite resin, increasing from 36.8 percent in 2004-05 to 48.5 percent in 2008-09, an increase of 11.7 percent. When clinical instructors were asked to state their preference if they themselves were to undergo posterior restoration, similar results were obtained. Instructors with less than ten years' experience preferred posterior composite resin restorations in 54.8 percent of the hypothetical situations, compared with 37.2 percent preferred by instructors with ten years of experience or more. It appears that the use of composite resin was influenced mainly by the prevailing trend and was not based on scientific evidence. Dental faculties should define criteria, based on up-to-date clinical studies, for using new materials, taking into consideration differences among instructors regarding treatment concept.     

Marginal adaptation of amalgam and resin composite restorations in Class II conservative preparations.

OBJECTIVE: The purpose of this study was to compare and contrast the performance, in terms of marginal adaptation, of a non-gamma-2 amalgam alloy with a compact-filled light-cured composite in the restoration of Class II preparations of conservative design. METHOD AND MATERIALS: Fifty recently extracted teeth were selected for the study. The teeth were restored with either a non-gamma-2 amalgam alloy, Dispersalloy, or a compact-filled resin composite, Z100, using standard techniques. The marginal adaptation of the restorative materials to the proximal surface outline form of each preparation was assessed at magnification x30. RESULTS: Highly significant differences were demonstrated in the mean percentages of perfect margins in all 3 segments of the proximal boxes of the restorations with the resin composite performing significantly better than the amalgam. The percentages of marginal fissuring were significantly higher in the amalgam restorations, except at the cervical margin, where the incidence of fissuring was almost the same for the amalgam and resin composite restorations. The resin composite restorations had significantly fewer underfilled margins than the amalgam restorations. CONCLUSION: In the conservative Class II preparations, the amalgam restorations were of poor quality with respect to marginal adaptation, compared with the resin composite restorations. It is suggested that the use of amalgam as a control in a clinical evaluation of resin composite restorations in conservative preparations cannot be justified, because it is apparently not possible to compare restorations of equivalent initial quality.     

Posterior composite resin inlays and onlays: a comparison of available systems

With the increasing proliferation of materials and techniques for placement of posterior composite resin restorations, the dentist must have the information to make informed judgements on which to use in various clinical situations. This paper examines the advantages and disadvantages of each of three systems: 1) Direct, 2) Direct/Indirect and 3) Indirect. The increased demand for posterior esthetic restorations has been one of the hallmarks of the eighties. According to a recent American Dental Association survey, the use of resin restorations in posterior teeth is markedly increasing and is the restoration of choice over amalgam for 70 percent of those dentists who responded to the survey. For the restorative dentist who chooses to do posterior esthetic restorations, the biggest challenge lies in acquiring the knowledge and judgement to know which of the three current classes of materials and techniques to apply to each clinical situation. Although the influx of new materials into the marketplace makes it difficult to evaluate and categorize these materials as accurately as would be desired, generally, posterior composite resins can be classified in three general categories based on method of placement. These categories are: a) Direct placement b) Direct/Indirect placement or Direct Composite Inlay (DCI) c) Indirect placement     

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.     

Defective restoration repair or replacement: An American Dental Association Clinical Evaluators Panel survey

BackgroundClinicians often encounter defective restorations and are faced with the difficult decision of whether to repair the existing restoration or replace it.MethodsAn electronic survey on repairing or replacing defective restorations was developed to assess how clinicians are making these decisions and the technical aspects considered when making a repair. E-mails containing the survey link were sent to the American Dental Association Clinical Evaluators (ACE) Panel on August 14, 2019, and the survey remained open for 2 weeks. Nonrespondents were sent reminders 1 week after deployment.ResultsApproximately 4 of every 5 respondents repair defective restorations. The top 3 conditions for making these repairs were noncarious marginal defects (87%), partial loss or fracture of the restoration (79%), and crown margin repair due to carious lesions (73%). Among respondents who repair defective restorations, almost all repair direct resin composite (98%), whereas approximately one-third do not repair the other restorative materials (that is, amalgam, glass ionomer, and fractured indirect all-ceramic crowns). Resin composite is used most often to repair resin direct composite restorations, and likewise, glass ionomer is used most often to repair glass ionomer restorations. Only 54% of respondents use amalgam to repair amalgam restorations. Surface treatments varied among the 3 available restorations types.ConclusionsMany dentists are actively making restoration repairs, but choosing clinical scenarios to make these repairs is material dependent.Practical ImplicationsThe repair of defective restorations is an acceptable and more conservative alternative than restoration replacement, and its success depends on proper case selection, material, and technique.     

Composite veneering of complex amalgam restorations

In large posterior cavities, indirect restorations could provide improved performance when compared to direct restorations, but with higher cost and removal of sound tooth structure. Improved mechanical properties have resulted in good clinical performance for amalgam in large cavities but without an esthetic appearance. Resin composites have become popular for posterior restorations, mainly because of good esthetic results. A restorative technique is presented that combines the esthetic properties of directly bonded resin composite and the wide range of indications for amalgam in stress-bearing areas.     

Posterior amalgam restorations--usage, regulation, and longevity

The use of dental amalgam has declined, but in most of the world, amalgam is the most widely used and widely taught direct restorative material for load-bearing posterior restorations. There are few national regulations on the use of amalgam; however, there are several nations where few amalgam restorations are placed. Long-term studies have shown that under optimum conditions, posterior restorations of amalgam and resin composite last longer than reported previously and that amalgam restorations outlast composite restorations. In general practice settings, posterior amalgam and composite restorations both have lower longevities.     

One-year observations on a composite resin for Class II restorations

A study was conducted to compare the clinical performance of a proprietary composite resin with that of amalgam when used in the restoration of Class II cavities. A total of 124 paired restorations were placed. The restorations were evaluated by a team from the United States Public Health Service, Materials &; Technology Branch, Division of Dental Health, San Francisco, Calif.     

Risk aspects of dental restoratives: From amalgam to tooth-colored materials

Dental materials’ choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today tooth-colored materials like resin-based composites and ceramics are more and more successful. However, are we going to replace a good but biologically questionable material (amalgam) with an equal material (resin composite) being more esthetic but also biologically questionable For amalgam, long-term clinical studies reported some significant hints that in single cases amalgam may be a health hazard for patients, finally Norway banned amalgam completely. The main advantage of a resin-based composite over amalgam is its tooth-like appearance and more or less absence of extensive preparation rules. For many years it was believed that resin-based composites may cause pulpal injury. However, pulpal injury associated with the use of resin-based composites is not correlated with their cytotoxic properties. Nevertheless, resin-based composites and other dental materials require rigorous safety evaluation and continuous monitoring to prevent adverse events similar like with amalgam. Because of non-biocompatible pulp responses to resin-based composites and amalgam, they should not be placed in direct contact with the dental pulp. The less dentin remaining in the floor of preparations between resin-based composites or other dental materials is more likely to cause pulpitis. Percentage of patients and dental practitioners who display allergic reactions is between 0.7% and 2%. The release of cytotoxic monomers from resin-based materials is highest after polymerization and much lower after 1 wk. Substances released from resin-based composites have been shown to be toxic in cytotoxicity tests. Nevertheless, in vitro cytotoxicity assays have shown that amalgam has greater toxic effects than resin-based composites, sometime 100-700-fold higher. Altogether, the risk of side-effects is low, but not zero, especially for dental personnel.     

The use of dental amalgam in pediatric dentistry: review of the literature

Dental amalgam is widely used as a restorative material even though it is not esthetic and there has been extensive anti-amalgam rhetoric. Although other materials have improved greatly, amalgam has the proven safety record and best cost-to-benefit ratio. Clinical evidence indicates that, in the posterior permanent dentition--where esthetics is not a primary concern--the small, minimally prepared, amalgam restoration, with its margins and any caries-susceptible fissures sealed with resin fissure sealant, is the restoration with the best survival. Amalgam also remains the best direct restorative option when larger restorations are required. In the primary dentition, the data indicates that resin-based composite and resin-modified glass-ionomer serve very well.     

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.     

Mechanical properties of heat-treated composite resin restorative materials.

Clinical methods for heat treating composite resin restorations have been developed. In this investigation, the effect of heat treatments on the diametral tensile strength of composite resin was determined. The composite resin restorative materials were selected according to the manufacturers' suggested use for anterior or posterior teeth, filler particle composition, and light-cured or chemical polymerization. Samples were prepared according to American Dental Association specification No. 27, and heat treatments were accomplished with a Coltene DI 500 oven for curing at approximately 120 degrees C for 7 minutes. Heat treatment substantially increased the diametral tensile strength tested, with the exception of the anterior hybrid particle (p less than 0.05). Composite resins with fine-particle inorganic fillers were significantly stronger than hybrid and microfilled composite resins.     

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.     

Observations on a composite resin for class II restorations: two-year report

A clinical study was conducted to compare the performance of a commercial composite direct-filling resin with that of amalgam in Class II cavities. Of 124 paired restorations placed in 73 patients, 92 pairs were available at the two-year period. The restorations were subsequently evaluated at one and two years by a team of examiners from the Materials and Technology Branch of the Division of Dental Health, United States Public Health Service, San Francisco.     

The future of dental amalgam

This paper is a comment on 'The enigma of dental amalgam' by Carl Leinfelder published in 2004 in the Journal of Esthetic and Restorative Dentistry. In that paper a warning is stated against a too abrupt change from amalgam towards resin composite, because this will bring a lot of clinical problems due to the limited skills of todays' dentists in placing posterior composite resin restorations. However, the situation in The Netherlands is different since a gradual changeover from amalgam towards resin composites has taken place during the last decades and dental schools have skipped training in placing amalgam restorations out of the curriculum. Clinical studies on the longevity of amalgam and resin composite restorations placed by dental students and dentists who are experienced in both composite resin and amalgam placement show a comparable and acceptable annual failure rate for those restorations. It is concluded that a gradual changeover from amalgam towards composite resin is preferred to avoid clinical problems.     

Fracture resistance of Class II approximal slot restorations

STATEMENT OF PROBLEM: Determination of the fracture resistance of various restorative materials in Class II approximal slot restorations has not been studied. PURPOSE: This study evaluated the effects of retention grooves and different restorative materials in Class II approximal slot restorations. To explore the possibilities for further research, the probable effects of preparation size and loading angle were investigated in a limited manner. MATERIAL AND METHODS: Ninety sound, caries-free human maxillary premolars were divided into 9 groups. The cavities were prepared either by hand or in a computer-controlled CNC machine with or without retention grooves. Four were restored with adhesive amalgam, another 4 with composite, and a single group with Compomer resin. The gingival floor depth was 1.5 mm. The specimens were loaded at an angle of 13. 5 degrees to their longitudinal axes by using a computer-controlled material testing machine until failure occurred. For one specific preparation of adhesive amalgam, loading was applied at 0 and 30 degrees to determine the probable effects of the loading angle. For a specific composite, resin application, the effects of the change in gingival floor depth were analyzed by assigning the depth to 2.0 mm. RESULTS: Composite and Compomer resin and composite exhibited better performance than amalgam. The existence of the retention grooves proved to be effective for adhesive amalgam restorations but did not have any advantageous effect in composite and Compomer restoration. CONCLUSION: For improved fracture resistance in small approximal restorations, the use of composite was the appropriate choice. Compomer also gave satisfactory results. Use of amalgam restoration should be accompanied with retention grooves and an adhesive system to improve its performance.     

Clinical evaluation of a composite resin system with a dentin bonding agent for restoration of permanent posterior teeth: a 3-year study.

This study evaluated the clinical performance of a visible light-cured small particle bimodally filled hybrid condensable composite resin system that included a dentin bonding agent compared with an amalgam alloy in class II restorations of permanent teeth. A total of 108 restorations were placed in 34 patients. Fifty-three composite resin and 55 amalgam restorations were inserted. Each restoration was evaluated immediately after placement and then on an annual basis for a 3-year period using the Public Health Service (PHS) criteria. In addition, the Moffa-Lugassy scale was used to measure the loss of material on the occlusal surface of these materials. One hundred percent of the resin and amalgam restorations were evaluated, measured, and reasons for replacement were recorded over the 3-year period. There was no significant difference (p greater than 0.05) in the clinical performance of the composite resin and the amalgam when evaluated by the PHS criteria. Analyses of wear at each of the three annual recall periods did not reveal any significant difference (p greater than 0.05) between the two restorative materials when measured by the Moffa-Lugassy scale.     

The clinical performance of a posterior composite resin restorative material, Heliomolar R.O.®: 3-year report

A posterior composite resin restorative material was evaluated over a 3-year period by means of a controlled clinical trial. A total of 52 composite resin restorations and 52 amalgam alloy restorations were included in this trial, and were examined with regard to marginal integrity, surface texture, anatomical form and proximal contact with adjacent teeth. There were no significant differences in clinical performance between test and control materials, which both gave good service over the period of evaluation. Only five restorations (one of amalgam and four of composite resin) failed during the trial. Plastic replica dies were used to support the clinical examinations of the restorations, and such dies were found to be helpful.     

Critical appraisal. Class II composite resin restorations with gingival margins in dentin

The rising demand for esthetic restorations has considerably increased the number of direct composite restorations being placed in private practices. While composite resin is often selected primarily for its esthetic qualities, another significant advantage of direct composite restorations is the ability to perform conservative cavity preparations. The traditional configuration used for amalgam restorations is no longer mandatory; thus, more sound tooth structure can be preserved.
The technique of composite placement is complex when compared to amalgam placement. The use of adhesive systems prior to placement of composite restorations requires not only excellent isolation to avoid contamination, but also precise manipulation of the adhesive system. While stable bonds to enamel are routinely obtained, the heterogeneous composition and intricate morphology of dentin makes this substrate more challenging to restore. In addition, the cavity configuration (C-factor) and inherent polymerization shrinkage of composite resin play an important role in the durability of the composite–dentin interface. Class II preparations often have gingival margins in root surfaces because of the location of the caries lesion. Clinicians are then faced with a preparation that is challenging to isolate, has a relatively high C-factor, and relies on optimal bonding to dentin to secure long-lasting marginal integrity. Various restorative techniques, such as incremental placement or the use of an intermediate layer (flowable composite or resin-modified glass ionomer cements—open sandwich technique), have been some of the methods proposed to increase the longevity of composite restorations, especially those with margins in dentin. This review evaluates some of the published research on Class II composite resin restorations with margins in the dentin/cementum.     

Clinical performance of a packable resin composite for posterior teeth after 3 years

There is a wide range of materials suitable for posterior resin-composite restorations. The objective of this clinical study was to evaluate the clinical performance of a packable resin composite (Solitaire, Heraeus-Kulzer, Hanau, Germany) in stress-bearing posterior cavities according to the Ryge criteria every 6 months over a 3-year period. A total of 250 class I (28%) and II (72%) restorations were placed in 120 patients using adhesive-bonding techniques without the use of rubber dam. After 3 years, 165 restorations (66%) were still in place during the follow-up investigation. Twelve restorations (4.8% out of the baseline number) had to be replaced due to postoperative sensitivity over the 3-year evaluation period. After 3 years, 65.5% of the restorations were scored Alpha for Marginal Adaptation, 18.2% Bravo, 2.4% Charlie, and 13.9% Delta. For the Ryge criteria Anatomic Form 70.9% of the restorations were scored Alpha, 15.2% Bravo, and 13.9% Charlie. Secondary caries was documented in 3.5% of the restorations. A Bravo score for Marginal Discoloration was determined in 26.1% of the restorations; 2.1% were scored Charlie. After 3 years, only 79.0% (summation effect of negative scores) of the restorations were still performing at clinically acceptable levels. Therefore, the packable resin composite Solitaire failed the criteria of the American Dental Association for resin restoratives. Bulk fractures (14 molar and 9 premolar restorations = 9.2% of the baseline number) due to poor physical properties of the material were the main reason for clinical failure.