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Biomedical subjects

W H Liebenberg

Publications and source records attributed to W H Liebenberg.

At least 19 recordsLinked to original sources
PubMed2001

Partial-coverage posterior ceramic restorations. Part 1: a return to diligence.

UNLABELLED: The application of multisurfaced tooth-colored restorations in the posterior dentition is an exercise in risk tolerance when dentin occupies the bulk of the tooth substrate. Not only is interfacial integrity capricious, but also a recent in vivo study has confirmed that dentin bond strengths deteriorate with time. Although the literature is replete with esthetic guidelines for posterior restitution, most practicing clinicians appreciate the prime tenet that clinical success involves more than esthetic realism in the posterior dentition. Success with indirect ceramic restorations is dependent on interfacial integrity, which, although multitudinous, is contingently related to operative competence. Innovative clinical techniques are described in this two-part article, along with a discussion of the probationary status of current adhesive options and the need for excellence in all phases of this demanding restorative sequence. CLINICAL SIGNIFICANCE: Restorative success in the posterior dentition is profoundly influenced by the variability of operative competence and diligence. This article discusses the precincts of posterior indirect ceramic restorations and submits a number of innovative solutions to the clinical challenge.

Bicuspid↗
PubMed2001

Partial-coverage posterior ceramic restorations. Part 2: operative innovations.

UNLABELLED: The application of multisurfaced tooth-colored restorations in the posterior dentition is an exercise in risk tolerance when dentin occupies the bulk of the tooth substrate. Part 1 of this article discussed the capricious nature of dentin bonding and acknowledged the prime tenet that clinical success involves more than esthetic realism in the posterior dentition. Success with indirect ceramic restorations is dependent on interfacial integrity, which is contingently related to operative competence. Innovative clinical techniques are described in this article, along with a discussion of the need for excellence in all phases of this demanding restorative sequence. CLINICAL SIGNIFICANCE: Restorative success in the posterior dentition is profoundly influenced by the variability of operative competence and diligence. Part 2 of this two-part article offers innovative solutions to the unique challenges of partial-coverage ceramic restorations.

Bicuspid↗
PubMed2000

Controlling contacts and contours using preformed ceramic inserts.

Current adhesive techniques and materials that seal both enamel and dentin have revolutionized modern restorative dentistry. Unfortunately, the durability problems associated with direct polymeric materials of the past have not been adequately solved. Nevertheless, when cost and esthetics form part of the treatment decision process, patients presenting with Class 2 defects are most often provided with a direct restorative option. Direct composite resin restorations are fraught with problems largely related to the mechanical stresses that accompany polymerization shrinkage. A partial solution is to incorporate prefabricated ceramic inserts into the substance of the composite resin, thereby decreasing the volume of directly cured restorative material and effectively reducing the magnitude of the polymerization stresses. SONICSYS approx is a unique addition to the restorative continuum that takes the insert strategy one step further by using specifically shaped sonically driven diamond-coated preparation tips to adjust the cavity form to fit presized ceramic proximal inlays. The SONICSYS approx system represents a technique intermediate between a direct resin composite and a laboratory fabricated inlay. This article describes the background of this development, and the components and application of the system. In addition, within the presentation of a case study, operative innovations are introduced that improve interfacial integrity and allow for the conveyance of predictable contacts and proper physiological contour.

Adhesives↗
PubMed2000

Direct pressure provisionalization technique: a new open-tray technique for complete-arch rehabilitations.

An innovative direct technique that improves the accuracy of provisional acrylic resin restorations is introduced. A custom impression tray is modified to facilitate complete occlusal closure. This open tray is used to make an accurate overimpression prior to beginning tooth preparation procedures. Following tooth preparation, the acrylic resin-filled overimpression is returned to its intraoral position, and the patient occludes into the previously indexed impression material. The pressure overimpression technique is offered as an expedient technique for improving the accuracy of provisional restorations.

Acrylic Resins↗
PubMed2000

Assuring restorative integrity in extensive posterior resin composite restorations: pushing the envelope.

Clinicians are increasingly being called on to satisfy the restorative demands of patients who request tooth-colored restorations but are unable to afford an optimum indirect restorative option. Consequently, in clinical practice, the limits of the direct posterior resin composite technique are being stretched. There is a need for techniques that will satisfy the complex variables of clinical practice and allow for successful utilization of posterior resin composite in large cavity preparations. The objective of this article is to explain the rationale behind the materials and techniques involved in the delivery of these complicated restorations.

Adolescent↗
PubMed2000

The axial bevel technique: a new technique for extensive posterior resin composite restorations.

The objective of this article is to introduce a new preparation design that utilizes external axial bevels and a resin placement technique that involves selective application of 2 resins of different viscosity to optimize marginal integrity in large Class II restorations. The rationale behind the intricate application of material and procedural manipulations involved in the delivery of these complicated restorations is discussed.

Acid Etching, Dental↗
PubMed1999

Flowable resin composites as "filled adhesives": literature review and clinical recommendations.

There is increasing reliance on laboratory testing of new products. The clinical significance of many such studies can be questioned. To function clinically, bond strength must develop more quickly than the shrinkage stress. Oxygen inhibition of extremely thin resin layers prohibits establishment of the bond, perhaps particularly relevant for single-component dentin bonding agents. Use of thicker layers of radiolucent hydrophilic bonding materials can lead to difficulties during subsequent radiographic diagnosis and may contribute to degradation at enamel margins. Shrinkage stress is influenced significantly by many factors. The cavity geometry probably plays the most important role but cannot be controlled to any major extent by the operator. Shrinkage and modulus kinetics are also critical, involving variables such as content and type of monomers, the catalyst system, and the light intensity. In general, a high modulus of elasticity or more rapid polymerization leads to increased shrinkage stress. Combining a single-component adhesive as a dentin primer with a highly radiopaque flowable resin composite as a filled adhesive may help overcome these difficulties.

Composite Resins↗
PubMed1999

Partial coverage indirect tooth-colored restorations: steps to clinical success.

This article provides steps to clinical success with indirect partial coverage tooth-colored restorative options. The focus of this article is more on clinical technique rather than specific materials as there are an array of acceptable tooth-colored indirect materials on the market and each comes with specific and detailed manufacturer recommendations.

Cracked Tooth Syndrome↗
PubMed1999

Interproximal integrity of posterior partial-coverage ceramic restorations: sequence of delivery and finishing.

The conservative, nonretentive cavity design of partial-coverage ceramic restorations provides a number of distinct advantages over traditional cast-metal options. However, unique challenges are associated with precise delivery of the restoration and the cleanup of excess luting resin. Restorative success and long-term gingival health are dependent on interproximal integrity at the restoration-tooth interface. This article examines the variables that affect this integrity and introduces a number of innovative techniques that assure meticulous delivery of posterior partial-coverage ceramic restorations.

Acid Etching, Dental↗
PubMed1999

Intentional pulp capping: a clinical perspective of the adhesive experience.

UNLABELLED: A new standard of biocompatibility has evolved for dental tissues. This paper attempts to trace the extraordinary transformation of composite resin from dissident to healer. Intentional pulp capping is a logical progression of the adhesive era given the fact that current enamel-dentin bonding systems are biologically acceptable and potentially provide a gap-free therapeutic seal at the restorative interface. The probationary status of the adhesive pulp capping procedure is acknowledged; nevertheless, it is abundantly clear that there is a place for this treatment modality in clinical practice. PURPOSE: The objective of the accompanying pictorial essay is to give a clinical perspective of the author's experience with intentional pulp capping over the past seven years. The focus of this paper is the detailed examination of the clinical variables which influence the quality of the "seal" surrounding the exposed pulpal tissues.

Dental Caries↗
PubMed1998

SONICSYS approx: an innovative addition to the restorative continuum.

When cost and aesthetics form part of the treatment decision process, patients with Class II defects are invariably directed toward direct restorative options. Due to the mechanical stresses generated by polymerization shrinkage, direct composite resin restorations can be ineffective treatment modalities. One addition to the restorative continuum utilizes shaped, sonically driven, diamond-coated preparation tips to adjust the cavity form to fit presized ceramic inlay restorations. This article introduces techniques that allow proper contacts and contour to be achieved utilizing this addition to the restorative continuum.

Adult↗
PubMed1998

Dental dam patch: an effective intraoral repair technique using cyanoacrylate.

Secondary dental dam retention is a critical component of successful dental dam isolation and relates to the provision of an effective seal at the dam/tooth junction. Restorative success can be compromised if this seal is inadvertently interrupted during the operative effort. One such periodic mishap is entanglement of the bur and the interdental dam strip during caries or restorative removal. This invariably results in a gaping interproximal defect in the dam. This article discusses the importance of optimum isolation as it relates to current "wet bonding" adhesive procedures, and introduces a repair technique using a patch of dental dam and cyanoacrylate.

Adhesives↗
PubMed1998

Restoring proximal integrity in posterior composite resin restorations: innovations using Ceromers.

Clinicians are increasingly being called upon to satisfy the restorative demands of patients requesting tooth coloured restorations but unable to afford an optimum indirect restorative option. Consequently, in clinical practice the envelope of what was hitherto considered the limit of appropriate application of the direct posterior composite resin technique is increasingly being stretched. Although our aesthetic endeavours are fairly easily accomplished in the posterior dentition, interproximal integrity is in many instances wanting and a major cause of restorative failure. This report highlights some of the authors innovations using Ceromers which satisfy the complex variables of clinical practice optimizing proximal contour, allowing for the successful utilization of posterior composite resin in the posterior dentition.

Ceramics↗