Adhesive systems for tooth-colored restorations. A review

The quality, longevity and the esthetic appearance of tooth-colored restorations are primarily dependent upon the integrity of the bond of the restoration with the enamel and dentin. Consequently, the enamel and dentin adhesives which are increasingly combined in the so-called adhesive systems play key roles in restorative dentistry. This paper describes the components, the clinical technique, the importance of the systems and the relevant adhesive mechanisms.     

Pre-hospitalization management of evolving myocardial infarction. 2d conference of south-eastern region emergency medicine experts

Since the development of advanced adhesive technology, the use of amalgam has declined significantly. The search for amalgam substitutes, i.e., restorative materials which maintain similar clinical function and cost-effectiveness as amalgam, has so far been unsuccessful. It has also become evident that a considerable confusion prevails regarding the objectives of restorative procedures. In absence of national and international standards, the products--the restorations--are assessed according to varied criteria. In placing restorations, three objectives are attained, at most: a) tooth preservation, b) tooth preservation and function, and c) tooth preservation, function, and imperceptible restitution. The learning objective of this article is to discuss the positive effects that could be attained by defining the standards, terminology, and the quality assessment criteria for operative dentistry in regard to the patients and the dental profession.     

The epidemiology of Neisseria gonorrhoeae isolates in Greenland 1979-1990: the emergence, spread and disappearance of non-PPNG strains carrying the conjugative 38.9 kb plasmid

The aim of this study was to compare the clinical performance of an amalgam, a glass polyalkenoate (ionomer) cerment material and a resin-based composite material used in small Class II cavities in permanent teeth. All restorations were inserted under rubber dam. They were examined yearly for 3 years. One clinician continued the study up to 5 years. The clinical examination focused on two criteria: clinically acceptable and failure. In addition, impressions were taken of the prepared cavities immediately before restoration and at each clinical examination using an elastomeric material. The study comprised 274 Class II restorations (88 amalgams, 95 cerments and 91 resin composites) placed in 142 adolescent patients. One hundred and sixty-seven restorations were in molar and 107 in premolar teeth. Patient dropout after 5 years resulted in the loss of 161 restorations, evenly distributed for restorative material and type of tooth involved. Four amalgam restorations, 22 glass ionomer cerment and nine resin composite restorations failed. The glass ionomer cerment and amalgam restorations failed primarily due to bulk fractures, while the resin composite restorations failed due to secondary caries and bulk fractures.     

Selection of restorative materials, reasons for replacement, and longevity of restorations in Florida

The purpose of the present study was to obtain information relating to the types of restorative materials used, the main reason for replacement of restorations, and the age of failed restorations. Dentists in general dental practice in Florida were invited to record details from their own work pertaining to restorations. The diagnostic criteria were described and coded. The clinicians were not calibrated in the use of the criteria but they could call in for further explanation if needed. The 27 clinicians involved placed 2,035 restorations of which 53% were replacements of failed restorations. The increased use of resin based restorative material was clearly evident including posterior composites. The clinical diagnosis secondary caries was the most common reason for replacement of amalgam (56%) and composite (59%) restorations. Only discoloration showed a statistically significant difference in the reason for replacement of the two types of materials. The median age of the replaced amalgam restoration was 15 years and that of composite restoration was 8 years.     

Amalgam at the new millennium

Dental amalgam has served as an excellent and versatile restorative material for many years, despite periods of controversy. The authors review its history, summarize the evidence in regard to its performance and offer predictions for the future of this material. For the present, amalgam should remain the material of choice for economical direct restoration of posterior teeth. When esthetic concerns are paramount, tooth-colored materials, placed meticulously, can provide an acceptable alternative.     

The effect of core translucency on the aesthetics of all-ceramic restorations

Recent advances in ceramic technology have revolutionized aesthetic dentistry. When treating a single anterior tooth in need of a full-coverage restoration, a multitude of options in restorative materials and techniques is available to the clinician. The learning objective of this article is to present and evaluate a selection of all-ceramic dental materials currently available for aesthetic full-coverage crown restorations. When selecting an all-ceramic system, there are several major factors to consider, including the inherent translucency of the ceramic material and of the adjacent dentition, the color of the prepared tooth, and the forces anticipated in that region. Preparation and restoration of discolored and nondiscolored tooth structure are reviewed. The techniques presented can be utilized to obtain predictable results in the anterior region for aesthetic all-ceramic full-coverage restorations.     

Determinants of quality in operative dentistry

The definition of quality in operative dentistry has often, at least in part, been related to how well a cut preparation compares with an ideal preparation. The ideal preparation follows well-defined design principles. These design principles have their roots in empirical dentistry and scientific evaluations, the latter often being conducted in vitro. Because of the complexity of following these design principles practically, a large portion of dental education consists of perfecting cavity preparations. By focusing on how to cut these cavity preparations as closely as possible to the ideal preparation, dentists with high psycho-motor skills have been able to provide the public with restorative procedures of high standards over the years. However, because of the tendency of relating quality in operative dentistry to the ideal preparation, we found it justifiable to review the literature dealing with the cavity design principles of the Class II amalgam preparation. What triggered this review was a request from the International Dental Federation (FDI) to start a process leading to a scientifically based quality definition of dental restorations, a definition that determines how different factors, including cavity design principles, affect the longevity of both tooth and restoration. From our review, we conclude that patient response and restoration performance over time, rather than how closely a cavity preparation compares with the ideal preparation, will be of more significance in determining the longevity of a Class II amalgam restoration.     

Dental practitioners' experiences on the usefulness of restorative materials in Finland 1992-1996

OBJECTIVE: To analyse general dentists' choice of restorative materials in Finland, where the use of amalgam has significantly decreased and the use of composites increased during the past 10 years. DESIGN AND SETTING: Postal survey in 1997 to a random sample of general dental practitioners mainly working with adult patients. MAIN OUTCOME MEASURES: Percentage distribution of dentists' opinions. RESULTS: The response rate was 82%. Tooth-coloured restorations were considered to be more time consuming, technically complicated and to have shorter life spans. Most dentists were not willing to return to the wide-scale use of amalgam restorations. CONCLUSIONS: The rapid changes in the restorative material selection have not resulted in serious problems in restorative therapy.     

Replacements of restorations in the primary and young permanent dentition

The present study focused on the type of restorative material used and the reasons for replacements of restorations in the primary and the young permanent dentition. All patients with restorations and who were 8 and 19 years of age in 1995 and were regularly treated at 11 Public Dental Health clinics in J?nk?ping County, Sweden, participated in the study. Data were extracted from the records for all types of restorations in canines and molars for the preceeding of 5 years for the 8-year-olds (i.e. from 3 to 8 years of age; n = 546) and for approximal restorations in premolars and molars for the preceeding 13 years for the 19-year-olds (i.e. from 6 to 19 years of age; n = 606). In all, 6012 restorations were evaluated. The two most common restorative materials used in the primary dentition were compomer and glass ionomer cement and in the young permanent dentition composite and amalgam. In the primary dentition, 29% of the restorations had been replaced and 4% of the teeth with restorations had been extracted. Thus, 33% of the restorations in the primary dentition failed. The corresponding figure for the young permanent dentition was 13%. The most common reason for replacements in the permanent dentition was secondary caries. That restorations often fail because of caries and that the development of secondary caries is not prevented by replacement of an old restoration indicate that more attention should be paid to preventive dental care for patients with restorations in the primary as well as in the young permanent dentition.     

The aesthetic composite anterior single crown restoration

Achieving natural aesthetics by harmoniously matching the shape and color of a single anterior crown is perhaps one of the greatest challenges in restorative dentistry. The clinician must often rely on the artistic skills of a laboratory technician who has no direct access to the patient. The shade selection process is, therefore, impaired, and the final result may be a restoration which does not emulate the aesthetics of the adjacent natural dentition. The learning objective of this article is to present an innovative technique which utilizes the qualities of high strength laboratory processing in association with the application of light curing and freehand bonding of composite resins. This combination allows the clinician to predictably achieve aesthetic results with single anterior crowns. The direct, indirect, and indirect/direct restorations are discussed, and the laboratory and clinical procedures are reviewed.     

Posterior composite resin restorations: operative innovations

The adhesive revolution is alleviating reservations regarding posterior composite resin restorations, established by past experience with outdated materials and techniques. Improved materials, instrumentation, and placement techniques have enhanced the performance of current formulations of posterior composite resins over their predecessors. However, it is a clinician's operative skill that ultimately determines the quality of a restorative option. The learning objective of this article is to share the author's experience in attaining adhesive excellence with posterior tooth-colored restorations as well as aesthetic anatomic form, minimal postoperative sensitivity, and a bond which can weather the true test of success-durability. Optimal applications, dental dam requirement, importance of the first increment of composite resin, restitution of occlusal morphology, and the clinical application are discussed.     

The use of a new strain of Vibrio cholerae O139 as a producer of an enteric chemical vaccine

Amalgam remains unchallenged as a posterior restorative material. But its inability to bond to the teeth leads to some amount of microleakage at the restoration-tooth interface with associated problems such as post operative sensitivity, pulpal complications etc. Also a broken amalgam restoration requires replacement which will further weaken the tooth structure. Recently, 4-META has been introduced which can graft amalgam and composite to enamel, dentin and old amalgam restorations. In this study, the bonding and marginal sealing abilities of 4-META was assessed both at the tooth-amalgam interface and old amalgam fresh amalgam interface.     

Effect of organic peroxide additives on wear resistance of composite resin

The wear resistance of four proprietary posterior composite resins and amalgam were evaluated by an in vitro wear-testing system. Direct and indirect composite restorations were placed on occlusally flattened extracted molars. They were subjected to 400,000 cycles of artificial chewing. The vertical distance between the cavosurface margin and the worn occlusal surface, was measured to indicate the wear resistance of the restorative materials. The restorative systems, including a peroxide modifier, exhibited dramatic increases in wear resistance. The heat-treated composite inlay system exhibited minimal wear values compared to all other composite resins in the study. This system exhibited wear values that were less than those of the amalgam control group.     

Artificial caries formation around fluoride-releasing restorations in roots

Secondary caries is one of the most important factors leading to replacement of dental restorations. This investigation assessed the capacity of fluoride-releasing restorative materials to resist caries in vitro when used in roots. Class 5 cavities were prepared in the buccal and lingual surfaces of 30 extracted premolars. The six materials used were: glass-ionomer cement (Fuji), glass-ionomer cement with silver particles added (Ketac-silver), fluoride-containing composite resin (Tetric), composite resin (Silux plus), fluoride-containing amalgam (Fluor-Alloy) and high-copper amalgam (Dispersalloy). After 5 weeks in an acid gel for caries-like lesion formation, the teeth were sectioned longitudinally and examined with polarized light. The results showed that repair with glass-ionomer materials of a carious lesion may be of great importance in the prevention of secondary caries around the restorations in roots.     

Criteria for restoration replacement and restoration life-span estimates in an educational environment

The present survey assessed the subjective estimates of restoration longevity, the relative importance of the reasons to replace a restoration and the proportion of restorative treatment perceived to be carried out to replace previous restorations in a clinical setting where caries experience has been reported to be high. Three hundred and eight-four final-year dental students in Mexico City (64% female, mean age 23.2 years) made subjective longevity estimates (minimum acceptable, 'average' and ideal) for small and large amalgam restorations and cast restorations. Students attributed greater responsibility for restoration failure to patient-related factors than to dentist-related factors. The most important reasons given for the replacement of restorations were the presence of an active carious lesion and the presence of a lesion. The next most important reasons were the presence of fractured restorations, proximal overhangs or proximal marginal defects, and marginal defects. No marked differences could be detected in the restoration longevity appraisals compared either with other subjective estimations or to actual longevity figures, nor in the relative ranking of reasons to replace restorations between the estimates done by participants in this study and reports originating in low-caries settings.     

Benefits and disadvantages of tooth-coloured alternatives to amalgam

OBJECTIVES: To give the practising dentist scientifically based data to assist him/her in the responsible decision-making process necessary to weigh the options available to the patient if she/he prefers not to have an amalgam placed. DATA SOURCES: Based on the literature and on the research work, which was done in the author's department, the indications and limitations of the known alternatives of amalgam were formulated. DESCRIPTION OF ALTERNATIVES TO AMALGAM: With the exception of cast gold restorations, all alternatives require the strict use of adhesive techniques. When compared with similar amalgam restorations, placing composite restorations (if they are indicated) takes approximately 2.5 times longer because complex incremental techniques are needed. Despite all the efforts, direct composite restorations placed in large cavities still show unacceptable amounts of marginal openings. Tooth-coloured inlays are a better alternative for large restorations. These restorations must be inserted with adhesive techniques. With composite inlays it is difficult to achieve a composite-composite bond. Ceramic inlays may be micromechanically bonded to the luting composite. They all show clinically a good marginal behaviour and the use of ultrasonic energy may further simplify the application technique of aesthetic inlays. STUDY SELECTION: Papers describing the different techniques were used as a base for the corresponding chapter. To assess and compare the longevity of the different restoration types, literature data were used. We limited ourselves to papers reporting at least 5-year clinical data. Longitudinal, clinically controlled studies were preferred. However, to be more complete, retrospective, cross sectional studies were also included. LONGEVITY OF POSTERIOR RESTORATIONS: Amalgam shows excellent longevity data with studies up to 20 years. The average annual failure rate is 0.3-6.9%. Posterior composites are in the same range (0.5-6.6%), however, the study times are much shorter (max. 10 years). For tooth-coloured inlays much less data are available. Longevity is reported up to 6 years with annual failure rates of 0.6-5%. CONCLUSIONS: All aesthetic alternatives to amalgam require more complex procedures and more time. If cost benefit considerations are a concern, amalgam is still the most convenient restorative material for posterior teeth.     

Management of temporomandibular disorders in a restorative practice

Various disorders related to the masticatory muscles or to the temporomandibular joints may be encountered in a restorative dental practice. Most of them can be managed by the restorative dentist whose primary interest may not lie in the area of temporomandibular disorders. The term temporomandibular disorders is used in this discussion to denote the group of diseases of the masticatory system that involves primarily the temporomandibular joints, the masticatory muscles, and the occlusion of the teeth. The learning objective of this article is to describe temporomandibular disorders encountered in general practice. Managing these disorders in the general practice of restorative dentistry is not difficult and adds to the comfort of the patient and possibly to the success of the restorations.     

Biocompatibility of posterior restorative materials

Biocompatibility of dental materials is an important consideration for the patient, clinician, laboratory technician and manufacturer. This paper examines biocompatibility testing methods and the biocompatibility of posterior restorative materials, including amalgam, casting alloys, resin composites, dentin bonding agents, cements, porcelains and ceramics.     

The use of cantilever bridges

Replacement of missing teeth with fixed bridgework often involves producing full crown retainers on teeth on both sides of an edentulous space. Unfortunately, this approach can result in the destruction of much healthy tooth tissue, and the clinician must balance the benefits of replacing missing teeth with the amount of tooth preparation required. Current thinking in restorative dentistry places the preservation of tooth tissue at a premium, and most practitioners are happy to use techniques that embrace this philosophy. Because of this, cantilever bridges have an increasing role in dental practice, where the replacement for a missing tooth or teeth has one or more abutments on only one side of the edentulous space, being unsupported at the other. Cantilever bridges fall into several types, depending on the number of abutments and types of retainers. This article describes the various cantilever bridge designs, considers the biomechanics of these restorations, and provides guidelines for their clinical use.     

Dentoalveolar morphology: evaluation of natural root form versus cylindrical implant fixtures

The function of implant-supported restorations is now routinely achieved. As a result, the emphasis in restorative implant dentistry has shifted from function to aesthetics and the biocompatibility of the materials utilized. The learning objective of this article is to review the three major components essential to achieving natural aesthetics in implant-supported restorations--hard tissue dynamics, soft tissue dynamics, and dental aesthetics. Particular emphasis is directed to the dentoalveolar anatomy and morphology. Analysis of the tooth root morphology and dimensions has resulted in the design and fabrication of restorative components with dimensions that closely resemble the natural tooth anatomy and aesthetics. A system of transmucosal abutments has been designed, and its utilization is presented in this review.