Maya Zalkind

Effect of impression materials and techniques on the marginal fit of metal castings

The effect of two impression materials used in three different techniques was tested for the accuracy of the marginal fit of metal castings. Sixty identically prepared Ivorine teeth were divided into groups of 20. The following methods were selected to make impressions: (1) putty in a metal stock tray with simultaneous elastomeric impression wash, (2) copper band relined with autopolymerizing acrylic resin and subsequent light-body elastomeric impression material, and (3) copper bands with modeling compound. Faciolingual sections of the Ivorine teeth with cemented metal castings were examined by scanning electron microscopy (SEM) at x 100 magnification. Measurements of the thickness of cement layers were calculated both manually and by use of a recently developed computerized method. The differences in the gingival marginal gaps between various impression materials and techniques at both the facial and lingual surfaces were not statistically significant.

Hypersensitivity to methyl methacrylate: Mode of treatment☆☆☆★★★

This article describes the treatment of a patient who experienced a delayed hypersensitivity reaction associated with acrylic resin. Patch testing revealed an allergy to methyl methacrylate monomer. Patients with a known or suspected allergy of this type should be treated by alternative methods. Dental procedures in which negligible contact of the oral mucosa with methyl methacrylate are presented.

New all-ceramic indirect post-and-core system☆☆☆

The increasing demand for highly esthetic, biocompatible posts and cores has led to the development of metal-free, post-and-core systems. This article describes and evaluates an indirect method for the fabrication of an all-ceramic post and core.

Compatibility of a composite resin with pulp insulating materials. A scanning electron microscope study

Abstract A scanning electron microscope investigation of the interface between Adaptic and pulp insulating materials was conducted. The surface roughness, as caused by insulated materials, was observed to decrease in the sequence ZOE, Dycal, ZPC, and Copalite. Uncured Adaptic dissolved a cavity varnish. The clinical significance of these observations has been discussed.

Esthetic considerations in restoring endodontically treated teeth with posts and cores

Posts and cores are often required for the restoration of endodontically treated teeth. Many methods for making post-and-core reconstructions have been described. With the increased use of all-ceramic systems for esthetic tooth restorations, there is a need for esthetic core reconstructions. This article describes several methods for fabricating esthetic posts and cores.

Alternative method of conservative esthetic treatment for gingival recession

The health and appearance of gingival tissue play an essential role in esthetics. The esthetic function of the tissue is enhanced when it frames the restoration. With gingival recession, the effect of natural gingiva is created with pink composites or ceramics on the cervical part of the crown, as described in this clinical report. This goal depends on the absence of adverse effects on the color, shape, and health of the surrounding tissue. The new composites are more color stable and wear resistant, and the latest generation of dental bonding agents allows the bonding of composites to dentin, various metals, and porcelain. The application of soft-tissue colored composite on dentin cementum, enamel, or porcelain is a good solution for correcting gingival recessions.

Mouth-operated devices for handicapped persons

A mouth-operated device designed for paralyzed persons was described. This device enables invalid persons to perform simple, everyday actions. The uses and advantages of the instrument as compared to other types were discussed.

Observations on cavity liners for composite resin restorations

Adhesion or surface roughness and discoloration at the interface between pulpinsulating materials and composite resins were taken as indications for interaction between the resins and the insulating materials. Some interaction occurred between all insulating materials and resins investigated. After separation of the restorative resins, the interaction of Dycal with the different composite resins varied considerably and decreased in the following sequence: Opotow, Natural, and Adaptic. The interactions of ZOE with Natural and with Adaptic were similar and more pronounced than the interaction at the Adaptic-Dycal interface but less pronounced than at the Dycal-Natural interface. A very thin film of Tubulitec was found to adhere to the composite resins in some areas. The adherence of liners containing calcium hydroxide to dentin was found to be generally stronger than the bond between these liners and composite resins. Separation of the composite resins caused tears in the varnishes and frequently in Hydroxyline. Almost completely intact layers of the varnish Copalite were observed on dentin, but Zahnlack apparently dissolved to a great extent in the resins. Among the liners containing calcium hydroxide, Dycal and Tubulitec were found to give rise to a high pH in samples of saliva, but Hydroxyline did not. Porosity and a folded surface were observed for Hydroxyline, indicating the entrapment of the solvent beneath a dry superficial layer.

Direct core buildup using a preformed crown and prefabricated zirconium oxide post

This article describes a procedure that can produce a post and core in a reasonable chair time during a single session. With a preformed crown for core buildup, and being relatively rapid, this is a fairly simple procedure that has good results.

LAMINATE VENEER PROVISIONAL RESTORATIONS : A CLINICAL REPORT

T h e popularity of porcelain laminate veneers has increased since their introduction in the early 1980s for two reasons: a conservative tooth preparation and impressive esthetics with the ultrathin porcelain laminate veneers retained with resinous cement. 1,2 The laminate veneers can be used to restore stained, fractured, or malformed and malpositioned teeth. 3,4 Reduced chair time, increased patient compliance, economic feasibility, minireal discomfort or sensitivity after treatment, and esthetics have all contributed to their increased use. >a,s Glazed porcelain is a biocompatible and esthetic dental restorative material and the material of choice for laminate veneers. The porcelain etching technique with bonding to a composite cement has been confirmed as an acceptable treatment. 2&6 Some dentists routinely place provisional restorations, whereas others do not, mainly because of time constraints or concern about the durability o f the interim restorations. 7 The need for provisional coverage can be justified because of the patients appearance and occlusion. Provisional restorations may be required to prevent drifting of the prepared teeth and the extrusion o f teeth in the opposing arch. ~,8 Patients with high expectations may not be as willing to tolerate the appearance o f the anterior dentit ion without provisionalization. Various procedures are available to facilitate short-term biologically acceptable interim restorations. Direct and indirect venee r t e c h n i q u e s have been desc r ibed ; t hey use autopolymerizing acrylic resin, 9 visible l ight-curing resin, ~° and composites2 ~ This clinical report describes a technique for provisional restoration that uses a clear plastic vacuform matrix or putty matrix system and a preformed polycarbonate crown. The technique is less time consuming and expensive and has a more esthetic result than other techniques do.