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Biomedical subjects

R Grajower

Publications and source records attributed to R Grajower.

53 records · Page 3Linked to original sources
PubMed1977

A temporary space maintainer using acrylic resin teeth and a composite resin.

A one-session technique for preparing a temporary space maintainer has been described. The technique consists of attaching an acrylic resin pontic to etched surfaces of natural adjacent teeth by means of a composite resin. The main advantages of this technique are elimination of premature tooth preparation, good esthetics, fair strength, low cost, and rapid completion of the restoration without the need of a dental laboratory.

Acid Etching, Dental↗
PubMed1977

The construction of a crown for clasp-bearing teeth.

A method is described for the fabrication of clasp-bearing crowns. The technique involves the preparation of a thin gold transfer coping, on to which the bulk of the crown is cast in a later stage.

Acrylic Resins↗
PubMed1976

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.

Adhesiveness↗
PubMed1976

Reflectance spectra of natural and acrylic resin teeth.

A method has been described for determining the reflectance spectra of teeth at various parts of the tooth surface. The shape and size of the teeth were accounted for by appropriate experimental and mathematical techniques. In all instances where a subtle difference in tooth color was discernible, this difference was also apparent on the corresponding spectra. The spectra of acrylic resin teeth showed characteristic absorption shoulders caused by pigmentation. These shoulders did not appear in the spectra of natural teeth where the reflectivity gradually increased with increasing wavelength. Differences were observed in the colors as well as the spectra of teeth from different shade guides which were marked with the same shade number by the manufacturer. The method may be applied for control of the color quality of artificial teeth as well as the selection of pigments in order to obtain an appropriate shade range and to reduce effects of metamerism.

Acrylic Resins↗
PubMedDate not supplied

Temperature ofthe pulp chamber during impression taking of full crown preparations with modelling compound.

Temperature elevations were measured in the pulp chamber of full cast crown preparations during impression taking with modelling compound in copper bands. Uncontrolled flaming, controlled flaming, and water heating of the bands produced temperatures of 53, 44, and 41.5 C, respectively. The time involved in restoring the temperature in the pulp to 37 C was determined. The implications of delayed chilling are discussed.

Copper↗
PubMedDate not supplied

Marginal leakage of Class II glass-ionomer-silver restorations, with and without posterior composite coverage: an in vitro study.

The aims of this in vitro investigation were: 1) to assess marginal leakage around three types of class II restorations, using: a) a composite resin with a glass ionomer lining; b) a glass ionomer cerment with composite resin coverage; c) a glass ionomer cermet without composite resin coverage and 2) to study the effect of thermocycling on marginal defects, by means of radiographs and SEM micrographs of the margins. Fifty-eight class II cavities were prepared in extracted primary molars. The teeth were divided into three groups and restored as follows: Group A--Ketac Bond (liner) and P-30; Group B--Ketac Silver and P-30(sandwich); Group C--Ketac Silver only. The restored teeth were thermocycled and marginal leakage was assessed from the degree of dye penetration on the sections. Dye penetration at the occlusal margins increased in the sequence A less than B less than C. The differences between group C and Groups A and B were statistically significant. Severe penetration of the dye was observed at the cervical margins with no statistically differences between the groups. Deterioration of margins due to thermocycling was observed for all groups, but these defects were not evident on the radiographs. Ketac Silver with and without composite coverage did not prevent marginal leakage when utilized in class II restorations in vitro.

Cermet Cements↗
PubMedDate not supplied

The effect of VLC Scotchbond and an incremental filling technique on leakage around Class II composite restorations.

The object of this study was to determine the effect of VLC Scotchbond and of an incremental filling technique on microleakage around class II composite restoration in vitro. Four groups of 15-16 teeth each, were filled with the resin P-30 by one of the following techniques: A, Scotchbond and incremental filling; B, Scotchbond and bulk filling; C, Enamel Bond and incremental filling; D, Enamel Bond and bulk filling. The teeth were thermocycled, insulated up to 1 mm from the restorations, immersed in 2 percent basic fuchsin, embedded in acrylic resin and ground off to various depths, parallel to the plane through the vertical and the mesiodistal axes. Marginal leakage was assessed from the degree of dye penetration at the sections. Dye penetration at the occlusal margins was similar for all groups. Dye penetration at the cervical margins for the different groups increased in the sequence: A/C/B/D. Incremental filling resulted in a significantly lower dye penetration at cervical margins for both bonding agents. The differences resulting from the use of Scotchbond were not significant, if the same packing technique had been used. Best results were obtained with Scotchbond and incremental filling.

Adhesives↗
PubMedDate not supplied

In vitro assessment of the effect of Scotchbond on the marginal leakage of class II composite restorations in primary molars.

By means of dye penetration, the authors determined the microleakage at the interface of class II composite restorations in thirty-eight extracted or naturally exfoliated primary molars. Scotchbond was used as the bonding agent in half of the prepared cavities' dentin and enamel; the control group (B) used Concise bonding agent in the enamel only. The use of Scotchbond in class II cavities did not prevent marginal leakage under the conditions of this study.

Adhesives↗