Direct posterior resin composite restorations: new techniques and clinical possibilities. Case reports.

Direct adhesive resin composite restorations in posterior teeth are now a reality thanks to improvements in these restorative materials and adhesive techniques. However, correct selection and application of materials are vastly important to clinical success. Two restorative techniques are described in detail, in one, a low-viscosity resin composite is placed incrementally, and in the other a condensable resin composite is placed in bulk. The former allows for greater security, because it is more traditional and has already proved to have clinical longevity; the latter has the advantage of being a quicker and simpler procedure. However, both techniques provide restorations that faithfully copy the dental tissues and have all the advantages of adhesive procedures.     

Despite all--do we have an appropriate substitute for amalgam?

The ultimate success or failure of a restored tooth is largely dependent on clinical management. Clinicians may choose from a number of restorative materials, different clinical techniques and cavity preparation procedures. Composite resin has been used for nearly 50 years as a restorative material in dentistry. The use of this material has recently increased as a result of patients' demands for esthetic restorations. 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. Higher failure rates were observed in resin-based composite restorations as compares amalgam restorations. Secondary caries was the main reason for failure. Posterior interproximal resin-based composite restorations should be considered with caution, and their limited long-term performance should be kept in mind. Patients should be informed about the potential longevity of restorative treatment for posterior teeth as they make decisions about treatment for their oral restorative needs.     

Composite or amalgam? Not a black or white decision

Amalgam as a restorative material in dentistry is discussed because of believed toxic properties of the material, yet there is no scientific prove for the assumption. Adhesive restorations are a possible alternative for amalgam in restoring posterior teeth. For treatment of primary caries, the direct composite resin restoration has many advantages. When greater defects are to be restored, adhesive composite resin restorations become less favourable. At this moment no long term results are available for indirect adhesive techniques. For the time being it seems necessary to use composite resin as well as amalgam for the restoration of posterior teeth.     

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.     

A nonmechanical etiology: The adhesive design concept.

Advances in restorative material formulations and adhesive technology have expanded and created new treatment possibilities for dental practitioners. Due to this evolution, composite resins are being used with increasing frequency in posterior restorations. In order to successfully place these restorations, the clinician must understand the rationale for restorative material selection, preparation design, adhesive protocol, and composite resin placement. This article illustrates these considerations for placing a Class I posterior composite restoration.     

Direct composite resin restorations in posterior teeth

Direct adhesive composite resin restorations are being used extensively. A proper understanding of the technique and its indications has contributed to the widespread use of this restorative approach. Recent industrial developments brought novel technologies to dentistry including the introduction of nanofillers to the restorative procedures. This article reviews some features of this new type of composite resin, discusses its advantages over other materials, and presents an application technique for restoration of posterior teeth through a clinical case report.     

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     

Direct fiber-reinforced composite restoration in an endodontically-treated molar: a three-year case report

The reconstruction of structurally compromised non-vital posterior teeth may represent one of the most challenging adhesive-based restorative procedures. Several factors may influence the longevity of direct fiber-reinforced resin composite restorations: endodontic procedures prior to post cementation, dentin and/or post surface treatments, selection of the appropriate post design and architecture, resin composite polymerization and layering techniques. Thus, different specialties, such as endodontics and restorative dentistry, should work as a team to improve the longevity of restorations. This article presents three-year clinical results following reconstruction of a severely damaged endodontically-treated molar using direct fiber reinforced resin composite systems.     

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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。     

Direct posterior composite resin restorations: A review. 1. Factors influencing case selection

The principal factors that influence case selection for direct composite resin restorations in posterior teeth are discussed. These include the perceived preference for tooth-coloured aesthetics, survival rate and replacement of posterior composites, clinical problems and concerns such as occlusal surface defects and the numerous effects of the material's polymerization contraction, and the availability of alternative tooth-coloured techniques for restoring posterior teeth. Specific guidelines in case selection are suggested. A subsequent paper reviews controversial aspects of the restorative technique for posterior composites and, on this basis, defines important principles in the clinical technique.     

Achieving optimal aesthetics for direct and indirect restorations with microhybrid composite resins.

In aesthetic dentistry, material science has played a key role in the development of natural-appearing restorations. Despite the progress, there have been challenges in achieving a harmonious integration of direct and indirect posterior restorations. Although porcelain restorations provide natural aesthetics, ceramics cannot be applied via direct techniques. Consequently, composite resins are valuable alternatives for conservative posterior restorations. In addition, because of their differing physical and optical properties, optimal aesthetic blending with porcelain and resin cannot be routinely achieved. This article explores the potential of composite resins as a direct and indirect restorative option in achieving the most favorable natural blend in the posterior region.     

Polymerization contraction stress of resin composite restorations in a model Class I cavity configuration using photoelastic analysis

PURPOSE: An important factor that contributes to deterioration of resin composite restorations is contraction stress that occurs during polymerization. The purpose of this article is to familiarize the clinician with the characteristics of contraction stress by visualizing the stresses associated with this invisible and complex phenomenon. MATERIALS AND METHODS: Internal residual stresses generated during polymerization of resin composite restorations were determined using micro-photoelastic analysis. Butt-joint preparations simulating Class I restorations (2.0 mm x 5.0 mm, 2.0 mm in depth) were prepared in three types of substrates (bovine teeth, posterior composite resin, and transparent composite resin) and were used to examine contraction stress in and around the preparations. Three types of composite materials (a posterior composite, a self-cured transparent composite, and a light-cured transparent composite) were used as the restorative materials. The self-cured composite is an experimental material, and the others are commercial products. After treatment of the preparation walls with a bonding system, the preparations were bulk-filled with composite. Specimens for photoelastic analysis were prepared by cutting sections perpendicular to the long axis of the preparation. Fringe patterns for directions and magnitudes of stresses were obtained using transmitted and reflected polarized light with polarizing microscopes. Then, the photoelastic analysis was performed to examine stresses in and around the preparations. RESULTS: When cavity preparations in bovine teeth were filled with light-cured composite, a gap was formed between the dentinal wall and the composite restorative material, resulting in very low stress within the restoration. When cavity preparations in the posterior composite models were filled with either self-cured or light-cured composite, the stress distribution in the two composites was similar, but the magnitude of the stress was greater in the light-cured material. When preparations in the transparent composite models were filled with posterior composite and light-cured transparent composite material, significant stress was generated in the preparation models simulating tooth structure, owing to the contraction of both restorative materials. CLINICAL SIGNIFICANCE: Polymerization contraction stress is an undesirable and inevitable characteristic of adhesive restorations encountered in clinical dentistry that may compromise restoration success. Clinicians must understand the concept of polymerization contraction stress and realize that the quality of composite resin restorations depends on successful management of these stresses.     

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.     

Survey on the teaching and use in dental schools of resin-based materials for restoring posterior teeth

A survey was conducted of 100 dental schools worldwide to investigate the current teaching of posterior resin composite restorations. A 20 multi-part question questionnaire was emailed to the selected schools. Schools were selected by ability to understand and respond in English. The questionnaire consisted of four open-ended questions and 16 closed questions on topics such as material selection for restoring posterior teeth, preclinical teaching of resin composite for posterior teeth, restoration size, contraindications, matrix placement methods, lining use, adhesive selection and finishing. Forty-six schools responded. The outcomes showed all schools included the teaching of resin composite for posterior restorations but varied. The majority of schools (63%) no longer taught amalgam as the preferred posterior restorative material. Half of the schools surveyed set numerical clinical requirements for restoration placement. Australian schools had no requirements whilst 92% of Asian schools did. There was a consensus that larger restorations were less suitable for resin composite. Selection of adhesives depended on region. Generally, the schools surveyed showed minor variations philosophically in teaching of the use and placement of resin composite restorations.     

Aesthetic resin onlay restorations: 'rationale and methods'

Resin composite restorations have gained increasing popularity over the past two decades. This has been largely driven by a patient-orientated demand for the use of aesthetic restorative materials. It has occurred concomitantly with an improvement in the mechanical properties of available materials, and advances in our knowledge of resin bonding. Onlay restorations are advocated for a plethora of clinical applications. This paper considers the role of adhesive onlay restorations fabricated in resin composite in contemporary restorative practice, including the presentation of two case reports. Clinical Relevance: This case report describes a minimally invasive, aesthetic solution to provide cuspal coverage by means of either a direct or indirect resin composite onlay restoration, respectively.     

Blending incremental and stratified layering techniques to produce an esthetic posterior composite resin restoration with a predictable prognosis

Composite resin restorations play an ever-increasing role as routine restorations in everyday clinical practice. However, the long-term prognosis of these restorations is still widely debated and open to question. The restorative protocols are still evolving, whether for direct or indirect placement, and little evidence is available in the scientific literature as to the ideal choice of site, technique, and category for placement. This article discusses the problems encountered and suggests a clinical restorative protocol to optimize composite resin placement.     

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.     

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.     

Class I and Class II silver amalgam and resin composite posterior restorations: teaching approaches in Canadian faculties of dentistry

A 10-question survey was mailed to the 10 Canadian faculties of dentistry to determine current approaches to teaching undergraduates about silver amalgam and resin composite for posterior restorations in adults and children. Responses were received from all 10 pedodontic programs and from 8 of the 10 operative and restorative programs. The use of silver amalgam and posterior composite for restorations of primary and permanent teeth is covered in the curricula of all dental schools, but the relative emphasis on the 2 materials varies. In the operative and restorative programs, curriculum time devoted to silver amalgam is either greater than or equal to that devoted to posterior composite. Five of the 8 schools reported greater educational emphasis on silver amalgam for the permanent dentition; however, course directors noted that the preference among patients seen in clinics is tending toward composite restorations. Curricula appear designed to educate students about the optimal use of both materials. Requirements for performance of restorations during training generally do not specify the type of material; these requirements range from 60 restorations to 250 surfaces. Five of the 8 schools conduct clinical competency tests with both materials. The responses from the pedodontic programs were more diverse. The proportion of curriculum time devoted to each type of material in these programs ranged from less than 25% to more than 75%. Five schools reported more emphasis on silver amalgam, 3 schools reported equal emphasis, and 2 schools reported more emphasis on posterior composite. No clinical requirements were specified in any of the undergraduate pedodontic programs. Within some of the faculties, there were differences between the operative and restorative program and the pedodontic program with respect to emphasis on different materials for the posterior dentition.     

Clinical performance of posterior composite resin restorations.

Two formulations of posterior composite resin (P-30 and Bisfil-P) were evaluated and compared to a high-copper, dispersed-phase amalgam (Dispersalloy). One hundred twenty-eight restorations were placed in 27 patients so that each patient received at least one of each material. After 3 years of clinical service, all three restorative materials produced clinically acceptable restorations, according to US Public Health Service and Leinfelder criteria. The amalgam restorations, however, underwent less wear (44 microns) than did the posterior composite resin restorations (60 to 74 microns). Stratification of data by type of tooth, class of restoration, and size of restoration produced the same ranking of wear from lowest to highest: Dispersalloy, Bisfil-P, and P-30. Resin restorations showed 45% more wear in molars than in premolars, and more wear was associated with moderately sized restorations than with conservative restorations. The surface texture of restorations of composite resin with porous strontium glass filler was nearly as smooth as that of enamel and was significantly smoother than that of the restorations of composite resin with zinc glass filler or of unpolished amalgam.