Low Shrinkage Silorane Composites

Polymerization shrinkage of methacrylate composites utilizing bisphenol-A glycidal methacylate or urethane dimethacrylate has typically been about 3-3.5% by volume. Though adjustments have been made to filler loading, filler size, filler particle distribution, and improved silanization, the polymerization contraction still creates some significant clinical problems. A new composite utilizing a completely different chemistry has been released, with polymerization shrinkage of less than one percent. This article will review the clinical effects of polymerization contraction of composite resins, the nature and properties of this chemical form of composite, and potential clinical applications.

Repair Versus Replacement of Restorations

Dentists evaluate previously placed restorations every day to determine their acceptability. Many restorations have some defects associated with them. This article will review criteria useful to determine whether a restoration can be repaired, refurbished, or replaced. Methods and materials usefulfor repair will be discussed, as well as the science behind the decision-making.

Amalgam Restorations: To Bond or Not

This article will review the use of various liners used to eliminate microleakage in amalgam restorations. It will review the literature about whether amalgam restorations are improved by using a bonding process and if so specifically how it improves the patient outcome.

Using Multiple Bonding Strategies

There are many ways to bond to tooth structure, some micro-mechanical some chemical, some a combination. Different dentin bonding materials have different bonding strengths to differently prepared surfaces, and because of differences in their nature, different areas of tooth structure present peculiar bonding challenges. This paper will review a variety of material types, elucidating their particular bonding strengths and commenting on improved bonding strategies to increase durability, strength, and favorable pulpal response. In this discussion, resin dentin bonding systems, glass ionomers, Gluma, resin cements, and newer combined products will br reviewed.

The effect of occlusal forces on restorations

This review will focus on the effect occlusal forces, both normal masticatory force and paranormal bruxing and clenching force, have on various restorative materials and their interaction with the teeth through a variety of bonding mechanisms. Salient physical properties of each of the materials will be reviewed, as well as the effect occlusal force has on restoration durability.

Enamel craze lines

Enamel craze lines are a common clinical finding, especially in older patients and in patients who brux. These craze lines frequently are discolored and may present as clear in color, grey, or brown. The clinical question is, when do enamel craze lines need restoration and when should we leave them untreated? This review will look at enamel structure and the effects of occlusion, bruxing, temperature, and restorations on enamel structure. Recommendations will be made on how and when to deal with these cosmetic defects of enamel.

Prevention of dental disease versus surgical treatment

The members of the Minnesota legislature have debated methods by which access to dental care and treatment of dental disease can be improved at a cost lower than that of present delivery systems. This review sheds light on some significant aspects of what the dental profession has learned over the last century that has proven significantly beneficial to the overall health of the American populace. Recommendations are made in the use of cost-effective dental public health interventions that could be used to provide better access and improved dental health at lower cost.

Cementation: methods and materials. Part two

This is a review of the literature of the last 21 years about cementing or luting indirect restorations to tooth structure. Recommendations are made as to the surface preparation of precious metals, non-precious metals, indirect composite materials, and all available porcelain materials including feldspathic, luecite reinforced, lithium di-silicate, slip cast aluminum oxide, densely sintered aluminum oxide, and zirconia prior to luting. Using data from a variety of sources, product categories of materials and various bonding materials and procedures are ranked according to their bond strength and durability.

Clinical uses of glutaraldehyde/2-hydroxyethylmethacrylate (GLUMA)

Glutaraldehyde/2-Hydroxyethylmethacrylate (GLUMA) is a chemical frequenty used for desensitization of teeth and has other uses as suggested in the literature. Some newer recommendations have been made relative to its use during tooth preparation, as a disinfectant, rewetting during bonding, prior to cementation of crowns and bridges, and in dealing with pulpal exposures. This article will explore the science behind these and other applications for this chemical and its effect on the tooth structure and its local environment.

The effect of occlusal forces on restorations

This review will focus on the effect occlusal forces, both normal masticatory force and paranormal bruxing and clenching force, have on various restorative materials and their interaction with the teeth through a variety of bonding mechanisms. Salient physical properties of each of the materials will be reviewed, as well as the effect occlusal force has on restoration durability.

Extension for prevention: margin placement

This article will review the concept of extension for prevention popularized by G.V. Black around the early 1900s. Concepts of extension and prevention have changed over the years with a more informed knowledge of the caries process, improved materials, cutting instruments, and techniques. The reasons for placement of the outline form relative to the tooth morphology, gingival tissue, relationship to adjacent teeth, and the choice of material will be described for all of the materials used in restorative dentistry. Research will be cited to support the scientific basis for outline form placement.

The clinical significance of marginal fit

Clinical evaluation of restoration acceptability includes marginal adaptation, restoration and preservation of anatomic form, color match, cavosurface discoloration, and presence of marginal caries. This paper will review what is known about marginal fit of all materials relative to their acceptable fit. Some explanation will be given of how material properties affect marginal fit, what the expected longevity of different materials is relative to marginal fit, and how marginal fit affects development of secondary or marginal caries. Marginal fit is assumed to affect restoration longevity by either encouraging or discouraging microleakage and development of secondary or marginal caries. Marginal fit and its effect on the health of the gingival tissues have been reviewed in an earlier paper on polishing and will not be reviewed here. Is there some correlation between marginal fit of the various materials used in restorative dentistry and this assumption? This paper will review the literature found on Medline and present the science behind the clinical significance of marginal fit utilizing in vitro studies where necessary and in vivo studies whenever possible. Numerous authors replicating these studies are used to improve reliability and replicability.

Why do we polish? Part one

What does polishing oral hard tissues and restorations accomplish? The two parts of this review will describe the effect of polishing on various restorative materials and teeth; the development of biofilm and adherence of plaque to teeth and restorations; the effects of unpolished versus polished surfaces on gingival health and longevity of restoration; and techniques for polishing various restorative materials. A listing of available polishing materials is included in Part Two, which will appear in the July-August Northwest Dentistry.

Causes and treatment of root resorption

This article will review what is known about the classification, causes, and treatment of root resorptions that are either internal or external.

Tooth wear: when to treat, why, and how. Part two

Tooth wear has been described in the literature as physiologic--that is, normal, expected over the life span of an individual, and not creating a pathologic condition. It has also been described in pathologic terms as caused by stress, corrosion, and friction, utilizing a variety of mechanisms and affected by a host of endogenous and exogenous factors. From a clinician's point of view, when should we decide to restore a tooth or change the conditions in the mouth to protect the teeth; and what should we consider using to either prevent or restore abnormal--i.e, pathologic--tooth wear? This review in Part One (Northwest Dentistry, September-October 2009) looked at what is normal, non-pathologic tooth wear and etiologies associated with all forms of tooth wear. Part Two will discuss the effects of tooth wear in enamel and dentin, when it may be advisable to intervene in the wear processes diagnosed on specific patients, and what methods of prevention and restoration can be utilized to restore or maintain the dentition. This review will not look at the need for full mouth reconstruction due to wear.

Tooth wear: when to treat, why, and how. Part One

Tooth wear has been described in the literature as physiologic--that is, normal, expected over the life span of an individual, and not creating a pathologic condition. It has also been described in pathologic terms as caused by stress, corrosion, and friction, utilizing a variety of mechanisms and affected by a host of endogenous and exogenous factors. From a clinician's point of view, when should we decide to restore a tooth or change the conditions in the mouth to protect the teeth; and what should we consider using to either prevent or restore abnormal--i.e., pathologic--tooth wear? This review in Part One will look at what is normal, non-pathologic tooth wear and etiologies associated with all forms of tooth wear. Part Two will discuss the effects of tooth wear in enamel and dentin, when it may be advisable to intervene in the wear processes diagnosed on specific patients, and what methods of prevention and restoration can be utilized to restore or maintain the dentition. This review will not look at the need for full mouth reconstruction due to wear.

The therapeutic use of glass ionomer

This article will review the physical properties of glass ionomer restorative materials, their gingival reaction, and their mechanisms of therapeutic action. A description will be given of how glass ionomer materials affect bacteria, and its effectiveness at preventing secondary, or marginal, caries. A summary of in vivo performance, together with descriptions of therapeutic clinical applications and recharging with fluoride to improve clinical performance of glass ionomer restorations will be presented.

Atraumatic tooth preparation

One of the tenets of operative dentistry is to maintain the health and vitality of teeth whenever possible. Methods of tooth preparation can adversely affect the tooth structure and the pulp. This paper will review the research on methods and devices used to prepare teeth, the possible sequelae of tooth preparation, and the best methods that can be recommended from the research to maintain tooth vitality and marginal integrity.

Part one: The restoration of non-vital teeth: structural, biological, and micromechanical issues in maintaining tooth longevity

This manuscript will review research from 1967 to the present to find the best evidence for the reconstruction of non-vital teeth. The paper will review the contention that non-vital teeth are "more brittle" by analyzing the relevant physical properties of vital versus non-vital teeth; describe the structures of the tooth used to manage stress and strain; describe the formation of dentinal cracks and propagation of fracture planes through dentin; and analyze forces placed on human teeth and their effects on the tooth in Part One. In Part Two, the paper will describe the strength of various dowel and core designs relative to strength, retention, and durability and describe the results of testing various dentin bonding materials in strength and retention of dowels in non-vital teeth. The review will conclude with recommendations as to the materials and techniques in specific clinical situations best capable of single tooth reconstruction to ensure tooth longevity together with the scientific basis for their adoption.

The uses of silane and surface treatment in bonding

Silane (gamma-methacryloxypropyltrimethoxysilane) has been used in composite materials since their inception as the coating on filler particles that binds them to a resin matrix. But silane has been found to have other useful purposes. This article will describe clinical techniques utilizing the latest scientific information in repairing or adding to composite restorations, repairing porcelain restoration, and bonding porcelain restorations, posts, and other materials utilizing a resin luting material either alone or in conjunction with other surface treatments such as sandblasting.

The clinical significance and management of microleakage. Part two

This research reviews relevant articles related to microleakage from 1966 to the present. The review discusses what the sensation of microleakage is clinically; how dentin permeability is related to microleakage; how the quality of dentin affects permeability and microleakage; what the effects of bacterial infiltration from microleakage can be, as well as the body's defenses against bacterial infiltration within the tooth complex; how caries and microleakage are related; and how various materials and procedures can be used to limit microleakage. Part Two reviews the use of materials, technique, and procedures to limit microleakage, and specifically how the use of various dentin and enamel bonding materials can be used to limit microleakage.

The clinical significance and management of microleakage. Part one

This research reviews relevant articles related to microleakage from 1966 to the present. The review discusses what the sensation of microleakage is clinically; how dentin permeability is related to microleakage; how the quality of dentin affects permeability and microleakage; what the effects of bacterial infiltration from microleakage can be, as well as the body's defenses against bacterial infiltration within the tooth complex; how caries and microleakage are related; and how various materials and procedures can be used to limit microleakage.

Core restoration for crown preparation

This article will review the relevant literature fom 1991-2003, a period of time when adhesive resin luting materials became available and luting crowns with zinc phosphate cements decreased. The review wtill look at the principles suggesting when a core should be placed, what core materials function best, preparation design with a core, luting material choice with a core, and results of clinical trials. Amalgam cores are regarded as the strongest material, best able to withstand adverse stress and restore teeth having the greatest loss of tooth structure. Composite resins, whether chemically cured or light cured, reinforced or not, appear best capable of core restorationfor moderately broken down teeth. Glass ionomer materials are considered too weak to withstand stress as a core material, but are recommended as a base material tofill in undercuts and improve the accuracy of impression and fit of a crown.

In search of a gold standard

This is a review article of relevant research to offer best-practice advice to the practitioner regarding the choice of intracoronal indirect restorative materials. The paper reviews the use of cast gold, a variety of porcelain materials and indirect composite resin materials as inlay materials. Subjects reviewed are the effects on tooth strength, the effect of bonding the material on tooth strength, stress analysis on teeth using different restorative material choice of luting material, wear of the material and its antagonist surface and clinical research outcomes and conclusions.

25 years of veneering: what have we learned?

This is a review of the research completed over the 25 years in which dentists have been veneering teeth. Recommendations are made relative to the tooth preparation design for composite resin veneers and porcelain veneers. Material differences in a variety of applications are discussed together with recommended applications, indications and contraindications. From the research that has been reviewed, a series of best practices in the application of veneering materials and techniques is listed.

The use of a direct bonded microfilled composite resin veneer

This technique creates a direct bonded microfilled composite resin veneer that replicates the complex color distribution and surface texture of the natural tooth structure. Duplicating the complexity of natural tooth color can be repeated by recording the different layers of color used in their sequence of placement.

Techniques for achieving realistic color distribution in large composite resin restorations

A technique of using macrofilled and microfilled composite resins in conjunction with tints and opaquers has been described. The technique achieves a more realistic color distribution in large composite resin restorations, such as Class IV restorations, diastema closures, veneers, and large Class III restorations. In placing more natural distributions of color in composite resin restorations, a more pleasing appearance can be achieved.

Microleakage of composite resin and amalgam core material under complete cast crowns

Ninety extracted human teeth were used to compare the microleakage of composite resin over, amalgam core, and regular crown preparations under a complete cast gold crown cemented with zinc phosphate cement as determined by 2% fluorescein dye solution. Specimens were compared with and without aging after cementation in a thermal bath by cycling some of them between 4 degrees C and 60 degrees C in a 2% fluorescein dye bath and others in a similar bath held at 37 degrees C. Fluorescein dye (under ultraviolet light) demonstrated microleakage of the specimens between the crown-tooth interface and the core-tooth interface. There were no significant differences in the microleakage due to aging. The specimens held at 37 degrees C in the fluorescein dye bath showed no significant differences between the core preparations and the regular crown preparations. However, when specimens were thermally cycled between 4 degrees C and 60 degrees C, there were significant differences. With thermal cycling, the regular crown preparations were better able to resist microleakage at the crown-tooth interface than either the composite resin core or the amalgam core preparations. The results of this investigation seem to indicate a need for further evaluation of core build-ups under cemented complete gold crowns.