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Biomedical subjects

G J Livaditis

Publications and source records attributed to G J Livaditis.

At least 19 recordsLinked to original sources
PubMed2001

Comparison of monopolar and bipolar electrosurgical modes for restorative dentistry: a review of the literature.

This review of the literature was undertaken as part of a wider investigation of effective hemostasis in vital pulp therapy. Two general types of electrosurgical units are available: monopolar and bipolar. This review compares the features of both systems. An important hazard referred to as channeling, funneling, or current crowding is described and associated with pulp therapy injury for the first time. Important safety features of bipolar electrocoagulation are identified and applied to dental procedures. Articles were selected by means of a search of MEDLINE, the U.S. National Library of Medicine's bibliographic database, for literature published between 1966 and 2001 on the topics of electrosurgery, electrocautery, electrolysis, and lasers. A search also was completed from a pulp therapy perspective to determine the use of electrosurgery on the pulp. Numerous articles and texts published between 1900 and 1965 had been reviewed previously; their bibliographies were explored and cross-referenced for pertinent reports. Laparoscopic applications of electrosurgery were reviewed for general background information and for clarification of safety and hazard issues; no exclusionary criteria or date limitations were imposed. Beyond the literature review, numerous authors and developers in the field of electrosurgery were contacted for clarification of concepts and controversies. More than 120 articles and texts related to electrosurgery were reviewed, and another 100+ articles were reviewed in the area of pulp therapy.

Dental Pulp↗
PubMed2001

Vital pulp therapy with bipolar electrocoagulation after intentional pulp exposure of fixed prosthodontic abutments: a clinical report.

A clinical protocol is described for the treatment of intentional and unavoidable exposed pulps during crown preparation. The protocol includes a definitive cavity preparation to create space in the exposed dentin for an adhesive pulp barrier; procedures to develop the highly desirable hybrid zone to prevent microleakage; the use of a specific resinous material that serves as a long-term pulp barrier with a relatively neutral and biocompatible impact on the pulp; and the use of precise bipolar electrocoagulation to provide durable hemostasis for restoration of the pulp wall and a relatively clot-free surgical wound to facilitate healing. The protocol involves the application of gentle surgical and restorative procedures to support the inherent healing process to restore the health of the pulp. The patient presented was part of a larger investigation and was selected in an attempt to identify a fixed prosthodontic application of the proposed pulp therapy protocol.

Acrylic Resins↗
PubMed1999

Indexing procedures for converting removable partial dentures after extractions while the patient retains the prosthesis.

A new indexing procedure is described for the conversion of removable partial dentures when extraction of additional teeth is planned. Advantages and disadvantages of the indexing procedure are reviewed and compared with traditional treatment options. The new procedure facilitates the use of dental laboratory expertise and facilities and allows the patient to retain the prosthesis throughout the process. A component that includes teeth, denture base segments, and wire or cast clasps is created by the laboratory and attached by the dentist during the extraction visit as a simple denture repair procedure. The procedure can also be used to convert an existing partial denture to an immediate complete denture. Required clinical and laboratory procedures are described.

Acrylic Resins↗
PubMed1998

Fabricating abutment crowns for existing removable partial dentures using custom resin clasp analogs.

A universal approach for fabricating abutment crowns for existing removable partial dentures is described. A replica (analog) of the clasp assembly is generated and transferred to a traditional working cast, which includes the abutment die. The analog is incorporated into the working cast as a removable component to allow the formation of the crown contours. The article reviews in detail the procedures required to transfer accurately all the essential components and information from the mouth to the working cast while allowing the patient uninterrupted use of the removable partial denture. Prestabilizing the removable partial denture, creating the analog impression, avoiding errors due to soft tissue components, forming a precise analog base, selecting materials, generating a rigid resin analog, and prescribing a path of insertion and withdrawal to the analog are described. The method replicates all types of clasps and can generate all types of fixed prosthodontic retainers to function harmoniously with the existing partial denture.

Acrylic Resins↗
PubMed1998

Comparison of the new matrix system with traditional fixed prosthodontic impression procedures.

This article compares the methods and effectiveness of traditional fixed partial denture impression systems, which includes the matrix impression system, in relation to the registration of the finish lines and sulci of tooth preparations in the formation of a full arch impression. Concepts relating to custom trays, retraction, homeostasis, sulcular cleansing, sulcular flange registration, configuration and strength, viscosity of elastomeric impression materials, and delivering the impression material into the sulcus are reviewed. Several concepts are questioned and alternative procedures are proposed. Forces that impact the gingival tissues and determine the success of the impression are briefly described.

Dental Impression Materials↗
PubMed1998

The matrix impression system for fixed prosthodontics.

This article describes the instrumentation, materials, and clinical procedures for the matrix impression system. The matrix impression system uses a custom matrix to control the sulcular environment and to deliver impression material to the subgingival parts to be impressed. It describes the four types of forces involved in gingival displacement during impressions, effective delivery of impression material with simultaneous sulcular cleansing, and simplification of complex impressions with or without segmentation. The application of the matrix impression system is described for making routine impressions and for some atypical problems. The article also provides a detailed description of the formation and design of the matrix.

Dental Impression Materials↗
PubMed1997

Repair with a surveyed cast clasp while patient retains the partial denture.

A technique is described that allows a removable partial denture with a broken clasp or a removable partial denture in which an abutment has been extracted to be restored by the reattachment of a new cast clasp component or a complete surveyed clasp assembly. The technique is applicable to most clasp designs and can include attachment to the acrylic denture base or the metal major connector. The technique is distinguished from other repair techniques by (1) providing a cast clasp replacement, (2) allowing the patient to retain the prosthesis during the repair, (3) generating a precisely formed surveyed clasp assembly by the laboratory, and (4) including an efficient transfer mechanism for the precision clasp created in the laboratory to be attached to the removable partial denture in the dental office. A two-step impression procedure is used to ensure proper relation of the partial denture to the abutments.

Acrylic Resins↗
PubMed1997

Crown foundations with a custom matrix, composites, and reverse carving.

This article describes a restorative technique for the formation of composite cores for artificial crowns. The procedure uses a semirigid matrix with reverse carving to form the cores on substantially compromised teeth. The matrix allows the placement of the composite under pressure to reduce voids and gaps and permits completion of multiple cores simultaneously. Reverse carving enables development of a common axis for multiple cores. The dentist can perform the tooth preparation for the crown at the time of the core restoration. The effort commonly applied to developing tooth morphologic features in the core can be invested instead in the formation of the interim restoration. The remaining tooth structure, pin or post placement, and location of the finish line can be evaluated with the insight of a crown foundation and not merely as a traditional restoration.

Composite Resins↗
PubMed1986

Etched-metal resin-bonded intracoronal cast restorations. Part I: The attachment mechanism.

Numerous attempts have been made to increase the adhesive qualities of the luting medium. Investigators have attempted to modify the metal surface, the tooth surface, the luting material, or combinations. Although investigations have achieved limited success, the adhesive cement remains an elusive goal of restorative dentistry. This article described the etched-metal attachment mechanism as an intermediate phase between luting medium and adhesive medium. However the bond of the resin to the etched enamel and etched metal is not adhesion. Nevertheless, the continuity and microscopic dimension of the mechanical bond mimics the adhesion desired. Until that adhesive material is developed, the bonding mechanism will serve as an effective substitute. The attachment mechanism described is the basis for an improved restoration. Resin-bonded retention can compensate for insufficient frictional retention or may completely substitute for frictional retention prescribed in a resin-bonded retainer prosthesis. Etched-metal procedures for intracoronal restorations permits conservative tooth preparation, greater retention, and improved support of remaining cusps.

Acid Etching, Dental↗
PubMed1986

Etched-metal resin-bonded intracoronal cast restorations. Part II: Design criteria for cavity preparation.

Intracoronal cast restorations can now be designed without dentinal involvement and with minimal alterations of the enamel. Exposure of the dentin is avoided during cavity preparation unless necessitated by disease, trauma, or previous restorations. Bonded retention also compensates for reduced frictional retention and provides support to weakened cusps. This article compared conventional intracoronal cast restorations with a design based on resin-bond retention. The proposed etched-metal resin-bonded restorations were found to be less invasive and more retentive.

Acid Etching, Dental↗
PubMed1986

A chemical etching system for creating micromechanical retention in resin-bonded retainers.

A method of chemically etching selected nonnoble alloys has been developed. This report provided data supporting that an effective attachment is created between resin and etched metal. This system reduces the disadvantages in creating a micromechanical retention by the electrochemical approach. The simplification of the process and reduction in the equipment needed should encourage greater use of etched-metal resin-bonded retainers.

Acid Etching, Dental↗
PubMed1983

Resin-bonded retainers. Part I: Resin bond to electrolytically etched nonprecious alloys.

Nonprecious Ni-Cr casting alloys can be electrolytically etched to yield a highly retentive surface for micromechanical bonding of dental resins. The acid, current density, and etching time to achieve the retentive features are specific for each alloy. Conditions for etching one beryllium-containing and one non-beryllium-containing alloy are described. The tensile strength of a resin system to these alloys has been determined to be over two times the accepted value of the resin bond to acid-etched enamel.

Acid Etching, Dental↗